RU2824978C2 - Method of processing iron-zinc-containing wastes of metallurgical production - Google Patents

Abstract

FIELD: mining; metallurgy.

SUBSTANCE: invention relates to mining and non-ferrous metallurgy, in which iron-zinc-containing wastes are formed. Universal technology has been developed, which enables to process wastes of ferrous and non-ferrous metallurgy, including iron-zinc-containing sludge and dust, sludge and dust of converter production, sludge and dust of electric smelting production, blast-furnace sludge and dust, oily scale.

EFFECT: invention provides extraction of zinc in the form of oxide and zinc salts from metallurgy wastes, de-oiling of oily scale, production of iron of direct reduction.

1 cl, 5 dwg, 9 ex

Description

The declared technical solution generally relates to metallurgy, metalworking, chemical production, and in more detail to a group of inventions in the field of mining and processing production, non-ferrous metallurgy, in which iron-zinc-containing waste is generated.

In this case, the term “waste” in the declared technical solution by the applicant means iron-containing, zinc-containing, iron-zinc-containing sludge and dust, oily scale.

By the term “solid reducing agent” in the claimed technical solution, the applicant means coke, coal of various grades, coke fines, coal fines, coconut dust, and coal dust.

The claimed method is characterized by its universality and is intended for processing any types of iron-zinc-containing waste from ferrous and non-ferrous metallurgy and mining and processing production, including sludge and dust from converter production, sludge and dust from electric smelting production, blast furnace sludge, and oily scale. The claimed invention is universal due to the fact that it allows processing these wastes both separately and together - depending on the user's requirements, and ensures the implementation of tasks for introducing valuable raw materials contained in waste (dumps) from metallurgical production into production.

The claimed invention ensures an increase in environmental friendliness, a reduction in the cost of production of the metallurgical industry due to the utilization of environmentally harmful by-products, namely, it ensures the purification of zinc oxide from impurities of toxic zinc halides.

At the same time, the declared technical solution also provides the possibility of using standard equipment for the production of ceramic bricks for the purpose of processing waste from ferrous and non-ferrous metallurgy, i.e. to load existing brick factories for waste processing, while maintaining the possibility of serial production of ceramic bricks without any changes in the part affecting changes in equipment.

The level of science and technology examined by the applicant showed that the known methods of processing metallurgical waste, including iron-zinc-containing sludge and dust, sludge and dust from converter production, sludge and dust from electric smelting production, blast furnace sludge and dust, oily scale have certain, sometimes very significant, shortcomings that prevent their effective use for their intended purpose.

At the same time, the technical solutions identified by the applicant from the studied level of technology, known in the field of ceramic brick production, are also not capable in principle of processing metallurgical production waste due to the fact that they are intended for the production of ceramic bricks.

From the studied level of technology, the applicant identified an invention according to Russian patent No. 2283885 “Method for processing iron-zinc-containing waste from metallurgical production”. The essence is the processing of finely dispersed iron-zinc-containing waste from metallurgical production, including thickening and dehydration of the waste to a moisture content of no more than 10%, mixing them with a reducing agent, reductive heat treatment of the resulting mixture in a rotary kiln, distillation of zinc and capture of sublimates with the production of zinc oxides, characterized in that the dehydrated iron-zinc-containing waste is mixed with coal tar in an amount of 10-20% of the mass of the waste, pelletized, and the reductive heat treatment of the pelletized waste is carried out in the presence of a solid carbon-containing reducing agent in an amount of 20-40% of the mass of the processed waste and the resulting coal tar pyrolysis products with the supply of counter-current air blast to the furnace, wherein gaseous fuel is burned in the working volume of the furnace before ignition of the solid reducing agent and the coal tar pyrolysis products.

Thus, the known invention relates to the processing of finely dispersed iron-zinc-containing waste from metallurgical production (for example, dry and wet sludge and dust from gas cleaning systems of steelmaking, sintering and blast-furnace production) and by-products of coke-chemical production (for example, coal tar, sludge from coke batteries, dry coke quenching units, coke breeze) and can be used in ferrous and non-ferrous metallurgy.

The disadvantages of the known technical solution compared to the declared technical solution are:

- impossibility of de-oiling oily scale;

- the impossibility of using standard brick factory equipment, such as a tunnel, and/or chamber, and/or ring, shaft kiln, as high-temperature equipment;

- the impossibility of using standard brick factory equipment (a tunnel, chamber, and/or ring kiln) to purify zinc oxide from zinc halides;

- the impossibility of obtaining briquettes using standard brick factory equipment;

- the impossibility of combining high-temperature firing and drying of raw materials in one unit;

- low energy efficiency of equipment;

- the impossibility of using any type of carbon-containing reducing agent;

- absence of heat recovery from exhaust gases for heating air and drying briquettes;

- requires preliminary drying of raw materials before forming briquettes;

- does not allow the use of cooled flue gases, previously cleaned from zinc-containing dust, for cooling the recovered product;

- the absence of a system for the oxidation of exhaust gases in order to obtain zinc oxide and the oxidation of other components to higher oxides;

- does not allow obtaining dezincification products in the form of reduced iron mixed with the slag component, regulation of the basicity of the slag component;

- there is no possibility to regulate the degree of iron reduction;

- the impossibility of regulating the basicity of the slag component by adding alkaline sintering agents;

- does not apply to the development of a universal complex based on standard equipment for a ceramic brick production plant, which allows for the solution of all the listed problems in combination;

- the impossibility of forming briquettes with dimensions up to 350x350x350 mm;

- the use of briquettes that cannot be placed in standard equipment of a ceramic brick production plant - a tunnel, and/or chamber, and/or ring, and/or shaft furnace without special equipment;

- the presence of contact between the raw material and the furnace lining, which leads to rapid wear and destruction of the lining;

- the impossibility of regulating the duration of the raw material's stay in firing zones or stages with different air/fuel ratios, in firing zones or stages with different degrees of reducing gas environment.

From the studied prior art, the applicant has identified an invention according to patent CN100507031 "High-temperature direct reduction method for zinc-containing dust carbon-containing briquette", the essence of which is to provide a high-temperature method for direct reduction of zinc-containing dust and agglomerates dezincification, which uses a method for increasing the quaternary alkalinity of agglomerates (i.e.: (CaO + MgO) / (SiO ₂ + Al2O ₃ )) to improve the low rate of reduction and removal of zinc in zinc dust, without increasing the consumption of the reduction process. The method consists of the following stages: 1) analysis and determination of the composition of CaO, MgO, SiO ₂ and Al ₂ O ₃ in zinc dust with a zinc content of less than 5% by weight, calculate the quaternary alkalinity value (CaO + MgO) / (SiO ₂ + Al ₂ O ₃ ); 2) adding one or more of slaked lime, lime, limestone powder, dolomite powder and alkali steel slag powder to the zinc-containing dust. After uniform mixing, the alkalinity of the mixture should be controlled within the range of 1.3-2.6; 3) the mixture prepared in step 2) is added to one or more carbonaceous materials coal powder, coke powder, petroleum coke powder and graphite powder, uniformly mixed, and then rolled or pressed into agglomerates with a maximum thickness of not more than 50 mm; 4) the agglomerates obtained in step 3) are heated in the range of 1100-1350 °C for more than 10 minutes to reduce zinc evaporation and reduce iron oxide to metallic iron.

Thus, the known invention relates to the technical field of high-temperature direct reduction based on coal, in particular to a method for high-temperature direct reduction and dezincification of a zinc-containing dust carbon-containing briquette.

The disadvantages of the known technical solution compared to the declared technical solution are:

- impossibility of de-oiling oily scale;

- the impossibility of using standard brick factory equipment, such as a tunnel, and/or chamber, and/or ring, shaft kiln, as high-temperature equipment;

- the impossibility of using standard brick factory equipment - a tunnel, and/or chamber, and/or ring shaft kiln - to purify zinc oxide from zinc halides;

- the impossibility of obtaining briquettes using standard brick factory equipment;

- the impossibility of combining high-temperature firing and drying of raw materials in one unit;

- low energy efficiency of equipment;

- the impossibility of using any type of carbon-containing reducing agent;

- absence of heat recovery from exhaust gases for heating air and drying briquettes;

- requires preliminary drying of raw materials before forming briquettes;

- does not allow the use of cooled flue gases, previously cleaned from zinc-containing dust, for cooling the recovered product;

- the absence of a system for the oxidation of exhaust gases in order to obtain zinc oxide and the oxidation of other components to higher oxides;

- there is no possibility to regulate the degree of iron reduction;

- does not apply to the development of a universal complex based on standard equipment for a ceramic brick production plant, which allows for the solution of all the listed problems in combination;

- the impossibility of forming briquettes with dimensions up to 350x350x350 mm;

- the use of briquettes that cannot be placed in standard equipment of a ceramic brick production plant - a tunnel, and/or chamber, and/or ring, and/or shaft furnace without special equipment;

- the impossibility of regulating the duration of the raw material's stay in firing zones or stages with different air/fuel ratios, in firing zones or stages with different degrees of reducing gas environment;

- low time between repairs and long manufacturing time for replacement parts of the matrix press.

From the studied prior art, the applicant has identified an invention under patent CN113637852 "Method for extracting iron and zinc from dust collection ash and low-carbon sludge of metallurgical production". The essence is: (1) mixing materials: adding dust collection ash and low-carbon sludge of steel plant into the mixer in proportions, mixing with an appropriate amount of powder with reduced carbon content, and adding 1-2% of binder depending on the total amount. The moisture content of the material is 5-10% during mixing; (2) Drying and dehydration of pressure balls: the mixed materials enter the high-pressure ball manufacturing equipment, the diameter of the pressure ball is 30-50 mm, the finished ball is dried on a belt dryer until the humidity is less than 1%, and the compressive strength of the dry ball is 70-100 kN / cm ² ; (3) Rotary kiln iron roasting and dezincification of the material ball: the rotary kiln roasts the material, the roasting temperature of the material is controlled at 1000-1300 °C, and the roasting time is 1-2 hours. Through the optimization of the material ratio, the zinc recovery rate of the material during roasting can reach 95%. Above that, the iron content of the iron-rich slag is more than 62%, and the zinc content is less than 0.15%; (4) Cooling the residual gas of the rotary kiln roasting, removing dust and collecting zinc: the temperature of the residual gas of the rotary kiln roasting is 600-800 °C, and the dust collected at this time is 50-60% zinc oxide powder. After cooling by heat exchange to 200-300 °C, the tail gas of the dust collection is sent to washing.

Thus, the known invention relates to the field of recycling solid waste from metallurgical production, in particular to a method for extracting iron and zinc from dust-collecting and low-carbon sludge from metallurgical enterprises.

The disadvantages of the known technical solution compared to the declared technical solution are:

- impossibility of de-oiling oily scale;

- the impossibility of using standard brick factory equipment, such as a tunnel, and/or chamber, and/or ring, shaft kiln, as high-temperature equipment;

- the impossibility of using standard brick factory equipment - a tunnel, and/or chamber, and/or ring shaft kiln - to purify zinc oxide from zinc halides;

- the impossibility of obtaining briquettes using standard brick factory equipment;

- the impossibility of combining high-temperature firing and drying of raw materials in one unit;

- low energy efficiency of equipment;

- the impossibility of using any type of carbon-containing reducing agent;

- absence of heat recovery from exhaust gases for heating air and drying briquettes;

- does not allow the use of cooled flue gases, previously cleaned from zinc-containing dust, for cooling the recovered product;

- the absence of a system for the oxidation of exhaust gases in order to obtain zinc oxide and the oxidation of other components to higher oxides;

- there is no possibility to regulate the degree of iron reduction;

- does not apply to the development of a universal complex based on standard equipment for a ceramic brick production plant, which allows for the solution of all the listed problems in combination;

- the impossibility of forming briquettes with dimensions up to 350x350x350 mm;

- the use of briquettes that cannot be placed in standard equipment of a ceramic brick production plant - a tunnel, and/or chamber, and/or ring, and/or shaft furnace without special equipment;

- the presence of contact between the raw material and the furnace lining, which leads to rapid wear and destruction of the lining;

- the impossibility of regulating the duration of the raw material's stay in firing zones or stages with different air/fuel ratios, in firing zones or stages with different degrees of reducing gas environment;

- low time between repairs and long manufacturing time for replacement parts of the matrix press.

From the studied prior art, the applicant has identified an invention according to patent CN111575492 "Comprehensive method for cleaning zinc-containing dust sludge and slag from metallurgical production". The essence is a method for cleaning zinc-containing dust sludge and metallurgical slag, which includes the following stages: 1) zinc-containing dust sludge, carbon powder and a quenching additive from metallurgical slag are mixed and a spherical mixture is obtained; 2). the spherical mixture prepared in stage 1 is placed in a rotary hearth furnace for a high-temperature direct reduction reaction. Iron in the spherical mixture forms hot direct reduced iron, and zinc is reduced and volatilizes in the form of steam. After processing by the waste heat recovery system, zinc powder in steam is collected by the dust collection system; 3) the hot direct reduced iron obtained by the reaction in step 2 and the molten metallurgical slag obtained in the steelmaking shop are sent to the electric arc furnace for submerged reduction, mixed and heated, and the molten iron obtained by the reaction is sent to the converter shop to produce steel.

Thus, the known invention relates to the field of processing metallurgical slags and zinc-containing dust and sludge.

The disadvantages of the known technical solution compared to the declared technical solution are:

- impossibility of de-oiling oily scale;

- the impossibility of using standard brick factory equipment, such as a tunnel, and/or chamber, and/or ring, shaft kiln, as high-temperature equipment;

- the impossibility of using standard brick factory equipment - a tunnel, and/or chamber, and/or ring shaft kiln - to purify zinc oxide from zinc halides;

- the impossibility of obtaining briquettes using standard brick factory equipment;

- the impossibility of combining high-temperature firing and drying of raw materials in one unit;

- low energy efficiency of equipment;

- the impossibility of using any type of carbon-containing reducing agent;

- absence of heat recovery from exhaust gases for heating air and drying briquettes;

- does not allow the use of cooled flue gases, previously cleaned from zinc-containing dust, for cooling the recovered product;

- the absence of a system for the oxidation of exhaust gases in order to obtain zinc oxide and the oxidation of other components to higher oxides;

- the impossibility of obtaining products in solid form suitable for transportation by non-specialized transport, obtaining products of dezincification of raw materials and reduced iron in the form of briquettes of any shape and size;

- there is no possibility to regulate the degree of iron reduction;

- does not apply to the development of a universal complex based on standard equipment for a ceramic brick production plant, which allows for the solution of all the listed problems in combination;

- the impossibility of forming briquettes with dimensions up to 350x350x350 mm;

- the use of briquettes that cannot be placed in standard equipment of a ceramic brick production plant - a tunnel, and/or chamber, and/or ring, and/or shaft furnace without special equipment;

- the presence of contact between the raw material and the furnace lining, which leads to rapid wear and destruction of the lining;

- the impossibility of regulating the duration of the raw material's stay in firing zones or stages with different air/fuel ratios, in firing zones or stages with different degrees of reducing gas environment.

From the studied level of technology, the applicant has identified an invention according to Russian Federation Patent No. 2708125 "Method for processing zinc-containing metallurgical sludge", the essence of which is the processing of zinc-containing metallurgical sludge, including their drying, mixing the dried sludge with a carbonaceous reducing agent, high-temperature treatment of the resulting mixture at a temperature of up to 1100 °, reducing iron oxides to metallic iron and evaporating zinc, characterized in that the sludge is dried in a mixer-doser by adsorption dehydration with fine-grained brown coal semi-coke taken in a ratio of 1: 1.5-2, after which the moistened brown coal coke is separated by pneumatic separation and sent to an intermediate bin, and the dried sludge, mixed with a carbonaceous reducing agent in a ratio of 1: 0.5-1, is subjected to thermochemical agglomeration in a rotary hearth furnace, whereby the ferrocox obtained after firing is cooled and sorted into classes.

Thus, the known invention relates to the processing of zinc-containing waste, namely, sludge and dust from wet and dry gas cleaning of blast furnace, open-hearth, converter, electric steelmaking and other industries, and can be used in ferrous and non-ferrous metallurgy.

The disadvantages of the known technical solution compared to the declared technical solution are:

- impossibility of de-oiling oily scale;

- the impossibility of using standard brick factory equipment, such as a tunnel, and/or chamber, and/or ring, shaft kiln, as high-temperature equipment;

- the impossibility of using standard brick factory equipment - a tunnel, and/or chamber, and/or ring shaft kiln - to purify zinc oxide from zinc halides;

- the impossibility of obtaining briquettes using standard brick factory equipment;

- the impossibility of combining high-temperature firing and drying of raw materials in one unit;

- low energy efficiency of equipment;

- the impossibility of using any type of carbon-containing reducing agent;

- absence of heat recovery from exhaust gases for heating air and drying briquettes;

- requires preliminary drying of raw materials before forming briquettes;

- the absence of a system for the oxidation of exhaust gases to obtain zinc oxide and for the oxidation of the remaining components to higher oxides;

- does not allow obtaining dezincification products in the form of reduced iron mixed with the slag component, regulation of the basicity of the slag component;

- there is no possibility to regulate the degree of iron reduction;

- the impossibility of regulating the basicity of the slag component by adding alkaline sintering agents;

- does not apply to the development of a universal complex based on standard equipment for a ceramic brick production plant, which allows for the solution of all the listed problems in combination;

- the impossibility of forming briquettes with dimensions up to 350x350x350 mm;

- the use of briquettes that cannot be placed in standard equipment of a ceramic brick production plant - a tunnel, and/or chamber, and/or ring, and/or shaft furnace without special equipment;

- the presence of contact between the raw material and the furnace lining, which leads to rapid wear and destruction of the lining;

- the impossibility of regulating the duration of the raw material's stay in firing zones or stages with different air/fuel ratios, in firing zones or stages with different degrees of reducing gas environment.

From the studied level of technology, the applicant has identified an invention according to Russian patent No. 2240361 "Method for zinc removal and reduction (metallization) of iron oxide waste". The essence is waste briquetting, heating them in a rotating tubular furnace using a solid carbon-containing substance as a reducing agent, afterburning of furnace gases, cooling and trapping zinc-containing dust. Waste briquetting is carried out together with a solid carbon-containing substance in the form of crushed hard or brown coal. Briquettes are fed into a straight-through tubular furnace heated from the loading side by fuel-oxygen burners. In this case, the temperature of the briquettes at the furnace outlet is maintained in the range of 700-1000°C. The velocity of furnace gases in the straight-through tubular furnace, reduced to normal conditions: temperature of 20°C and pressure of 760 mm Hg, is set at 0.3-1.0 m/s. Before briquetting, the waste is preheated in a heating counter-current tubular furnace to a temperature of 550-1000°C. The invention will improve the efficiency of zinc extraction from waste and the reduction of iron oxides.

Thus, the known invention relates to methods for preparing raw materials in the metallurgical industry.

The disadvantages of the known technical solution compared to the declared technical solution are:

- impossibility of de-oiling oily scale;

- the impossibility of using standard brick factory equipment, such as a tunnel, and/or chamber, and/or ring, shaft kiln, as high-temperature equipment;

- the impossibility of using standard brick factory equipment - a tunnel, and/or chamber, and/or ring shaft kiln - to purify zinc oxide from zinc halides;

- the impossibility of obtaining briquettes using standard brick factory equipment;

- the impossibility of combining high-temperature firing and drying of raw materials in one unit;

- low energy efficiency of equipment;

- absence of heat recovery from exhaust gases for heating air and drying briquettes;

- requires preliminary drying of raw materials before forming briquettes;

- does not allow the use of cooled flue gases, previously cleaned from zinc-containing dust, for cooling the recovered product;

- does not allow obtaining dezincification products in the form of reduced iron mixed with the slag component, regulation of the basicity of the slag component;

- there is no possibility to regulate the degree of iron reduction;

- the impossibility of regulating the basicity of the slag component by adding alkaline sintering agents;

- does not apply to the development of a universal complex based on standard equipment for a ceramic brick production plant, which allows for the solution of all the listed problems in combination;

- the impossibility of forming briquettes with dimensions up to 350x350x350 mm;

- the use of briquettes that cannot be placed in standard equipment of a ceramic brick production plant - a tunnel, and/or chamber, and/or ring, and/or shaft furnace without special equipment;

- the presence of contact between the raw material and the furnace lining, which leads to rapid wear and destruction of the lining;

- the impossibility of regulating the duration of the raw material's stay in firing zones or stages with different air/fuel ratios, in firing zones or stages with different degrees of reducing gas environment;

- low time between repairs and long manufacturing time for replacement parts of the matrix press.

From the studied level of technology, the applicant has identified an invention according to Russian patent No. 2404271 "Method for processing substandard iron- and zinc-containing waste from metallurgical production", the essence of which is the processing of iron- and zinc-containing waste from metallurgical production, including thickening, dehydration and drying to a moisture content of 6-10 wt.% of waste in the form of iron- and zinc-containing sludge, mixing with a carbon-containing reducing agent and pelletizing, counter-current treatment of pellets with combustion products of gaseous or liquid fuel, distillation of zinc and capture of sublimates to obtain zinc oxide, characterized in that the dried iron- and zinc-containing sludge is mixed with iron- and zinc-containing dusts, oil-scale-containing waste from rolling production is added to the mixture in an amount of 0.04-1.00 parts by weight per 1 part by weight. mixture, and to the resulting mixture - dolomite burning waste or lime production waste and bentonite in quantities of 0.03-0.15 parts by weight and 0.006-0.009 parts by weight, respectively, per 1 part by weight of the mixture, the resulting raw material mass is pelletized with the addition of a carbon-containing reducing agent to obtain pellets of 10-25 mm in size, while natural gas, or used motor oils, or liquid oil waste from rolling production are used as gaseous or liquid fuel, and the pellets are processed with an air flow rate coefficient of 0.45-0.95 and a temperature of 1150-1450 ° C with a vacuum in the system of 15-160 Pa and a temperature of the waste processing products of 450-700 ° C.

Thus, the known invention relates to the processing of iron- and zinc-containing waste, dust and sludge from dry and wet gas cleaning systems of sintering, blast furnace, rolling, steelmaking and electric steelmaking production and can be used in ferrous and non-ferrous metallurgy.

The disadvantages of the known technical solution compared to the declared technical solution are:

- the impossibility of using standard brick factory equipment, such as a tunnel, and/or chamber, and/or ring, shaft kiln, as high-temperature equipment;

- the impossibility of using standard brick factory equipment - a tunnel, and/or chamber, and/or ring shaft kiln - to purify zinc oxide from zinc halides;

- the impossibility of obtaining briquettes using standard brick factory equipment;

- the impossibility of combining high-temperature firing and drying of raw materials in one unit;

- low energy efficiency of equipment;

- absence of heat recovery from exhaust gases for heating air and drying briquettes;

- requires preliminary drying of raw materials before forming briquettes;

- does not allow the use of cooled flue gases, previously cleaned from zinc-containing dust, for cooling the recovered product;

- there is no possibility to regulate the degree of iron reduction;

- does not apply to the development of a universal complex based on standard equipment for a ceramic brick production plant, which allows for the solution of all the listed problems in combination;

- the impossibility of forming briquettes with dimensions up to 350x350x350 mm;

- the use of briquettes that cannot be placed in standard equipment of a ceramic brick production plant - a tunnel, and/or chamber, and/or ring, and/or shaft furnace without special equipment;

- the impossibility of regulating the duration of the raw material's stay in firing zones or stages with different air/fuel ratios, in firing zones or stages with different degrees of reducing gas environment;

- the impossibility of using any type of carbon-containing reducing agent;

- the presence of contact between the raw material and the furnace lining, which leads to rapid wear and destruction of the lining.

From the studied level of technology, the applicant has identified an invention according to Russian patent No. 2667949 "Installation for processing zinc-containing raw materials". The essence is the use of an installation for processing zinc-containing raw materials, containing a metal casing in which evaporation and oxidation cyclone chambers and a slag drain with a tap hole for removing slag from the evaporation chamber are placed, and a loading device, characterized in that it is equipped with an induction furnace installed without a gap under the slag drain opening, wherein the ratio of the height of the induction furnace to its diameter is H / D = 0.1-0.5, the ratio of the length of the slag drain generatrix to the diameter is l / d = 0.1-0.5, and the ratio of the internal diameter of the induction furnace to the diameter of the slag drain is d / D = 0.1-0.5.

Thus, the known invention relates to the field of processing dusty waste from metallurgical furnaces containing iron and zinc both in the metallic state and in the form of oxides. The installation allows for the separation of waste to produce black cast iron and commercial zinc oxide used in the rubber, paint and varnish and other industries.

The disadvantages of the known technical solution compared to the declared technical solution are:

- impossibility of de-oiling oily scale;

- the impossibility of using standard brick factory equipment, such as a tunnel, and/or chamber, and/or ring, shaft kiln, as high-temperature equipment;

- the impossibility of using standard brick factory equipment - a tunnel, and/or chamber, and/or ring shaft kiln - to purify zinc oxide from zinc halides;

- the impossibility of obtaining briquettes using standard brick factory equipment;

- the impossibility of combining high-temperature firing and drying of raw materials in one unit;

- low energy efficiency of equipment;

- absence of heat recovery from exhaust gases for heating air and drying briquettes;

- does not allow the use of cooled flue gases, previously cleaned from zinc-containing dust, for cooling the recovered product;

- does not allow obtaining dezincification products in the form of reduced iron mixed with the slag component, regulation of the basicity of the slag component;

- there is no possibility to regulate the degree of iron reduction;

- the impossibility of regulating the basicity of the slag component by adding alkaline sintering agents;

- does not apply to the development of a universal complex based on standard equipment for a ceramic brick production plant, which allows for the solution of all the listed problems in combination;

- the impossibility of forming briquettes with dimensions up to 350x350x350 mm;

- the use of briquettes that cannot be placed in standard equipment of a ceramic brick production plant - a tunnel, and/or chamber, and/or ring, and/or shaft furnace without special equipment;

- the impossibility of regulating the duration of the raw material's stay in firing zones or stages with different air/fuel ratios, in firing zones or stages with different degrees of reducing gas environment.

From the studied level of technology, the applicant has identified an invention according to Russian patent No. 2548840 "Method for processing fine-grained zinc-containing waste from metallurgical production", the essence of which is the processing of fine-grained zinc-containing waste from metallurgical production, including dosing of zinc-containing waste from metallurgical production, solid fuel, binder and fluxing additives, mixing and pelletizing of the resulting charge, drying and heat treatment of pellets, characterized in that the dosing of the charge components is carried out with the provision of a carbon content in the charge of 80-100% of the stoichiometrically required for the direct reduction of iron and zinc in the charge and the melting temperature of gangue and ash of solid fuel in slag not higher than 1400 ° C, while the heat treatment of the pellets is carried out at a temperature of 1350-1450 ° C and a heating rate of 400-500 ° / min, after which the metallized product is separated from slag.

Thus, the known invention relates to the field of ferrous and non-ferrous metallurgy and can be used in the processing of fine-grained zinc-containing waste from metallurgical production to produce granulated cast iron and raw materials for non-ferrous metallurgy.

The disadvantages of the known technical solution compared to the declared technical solution are:

- impossibility of de-oiling oily scale;

- the impossibility of using standard brick factory equipment, such as a tunnel, chamber, and/or ring shaft kiln, as high-temperature equipment;

- the impossibility of using standard brick factory equipment - a tunnel, and/or chamber, and/or ring shaft kiln - to purify zinc oxide from zinc halides;

- the impossibility of obtaining briquettes using standard brick factory equipment;

- the impossibility of combining high-temperature firing and drying of raw materials in one unit;

- low energy efficiency of equipment;

- the impossibility of using any type of carbon-containing reducing agent;

- absence of heat recovery from exhaust gases for heating air and drying briquettes;

- does not allow the use of cooled flue gases, previously cleaned from zinc-containing dust, for cooling the recovered product;

- the absence of a system for the oxidation of exhaust gases in order to obtain zinc oxide and the oxidation of other components to higher oxides;

- does not allow obtaining dezincification products in the form of reduced iron mixed with the slag component, regulation of the basicity of the slag component;

- there is no possibility to regulate the degree of iron reduction;

- the impossibility of regulating the basicity of the slag component by adding alkaline sintering agents;

- does not apply to the development of a universal complex based on standard equipment for a ceramic brick production plant, which allows for the solution of all the listed problems in combination;

- the impossibility of forming briquettes with dimensions up to 350x350x350 mm;

- the use of briquettes that cannot be placed in standard equipment of a ceramic brick production plant - a tunnel, and/or chamber, and/or ring, and/or shaft furnace without special equipment;

- the impossibility of regulating the duration of the raw material's stay in firing zones or stages with different air/fuel ratios, in firing zones or stages with different degrees of reducing gas environment.

From the studied level of technology, the applicant has identified an invention according to Russian Federation Patent No. 2280087 "Method for Continuous Processing of Iron-Zinc-Containing Dusts and Sludges". The essence is reducing roasting in the presence of a reducing agent in a rotating tubular furnace without air access under controlled temperature conditions with the production of a metallized iron-containing product and a zinc product. The mixture of the starting material and reducing agent is pre-treated at a temperature of at least 400°C until the moisture content is no more than 0.05%, after which it is fed into the said furnace. Reducing roasting in the furnace is carried out due to contactless heating by a heat exchanger installed in the furnace by feeding fuel combustion products into it. Zinc condensate is obtained, which is captured and cooled with the production of a zinc product in the form of metallic zinc.

Thus, the known invention relates to the field of ferrous metallurgy and can be used for processing iron-zinc-containing materials that are industrial waste, for example, dust and sludge from gas cleaning of open-hearth and blast furnaces, as well as converters.

The disadvantages of the known technical solution compared to the declared technical solution are:

- impossibility of de-oiling oily scale;

- the impossibility of using standard brick factory equipment, such as a tunnel, and/or chamber, and/or ring, shaft kiln, as high-temperature equipment;

- the impossibility of using standard brick factory equipment - a tunnel, and/or chamber, and/or ring shaft kiln - to purify zinc oxide from zinc halides;

- the impossibility of obtaining briquettes using standard brick factory equipment;

- the impossibility of combining high-temperature firing and drying of raw materials in one unit;

- low energy efficiency of equipment;

- the impossibility of using any type of carbon-containing reducing agent;

- requires preliminary drying of raw materials before forming briquettes;

- does not allow the use of cooled flue gases, previously cleaned from zinc-containing dust, for cooling the recovered product;

- the absence of a system for the oxidation of exhaust gases in order to obtain zinc oxide and the oxidation of other components to higher oxides;

- does not allow obtaining dezincification products in the form of reduced iron mixed with the slag component, regulation of the basicity of the slag component;

- there is no possibility to regulate the degree of iron reduction;

- the impossibility of regulating the basicity of the slag component by adding alkaline sintering agents;

- does not apply to the development of a universal complex based on standard equipment of a ceramic brick production plant, which allows for the solution of all the listed tasks in combination;

- the impossibility of forming briquettes with dimensions up to 350x350x350 mm;

- the use of briquettes that cannot be placed in standard equipment of a ceramic brick production plant - a tunnel, and/or chamber, and/or ring, and/or shaft furnace without special equipment;

- the presence of contact between the raw material and the furnace lining, which leads to rapid wear and destruction of the lining;

the impossibility of regulating the duration of the raw material's stay in firing zones or stages with different air/fuel ratios, in firing zones or stages with different degrees of reducing gas environment.

From the studied prior art, the applicant has identified an invention according to patent CN110016569 "Method for Purifying and Using Secondary Zinc Oxide", the essence of which is the purification of zinc oxide, which includes the following stages: adding technical sulfuric acid to soot containing zinc oxide, granulating using a granulator and firing the particles in a rotary kiln for 3-5 hours at a temperature of 600-800 °C. The use of zinc oxide includes the following stages: adding 3-5 times the volume of the electrolyte residue to the purified secondary zinc oxide, for leaching, adjusting the pH of the final leaching point at a level of 3.3-4.1 by adding technical sulfuric acid, leaching for 4-5 hours and filtering to obtain a leaching liquor; adding hydrogen peroxide and lime milk to the leaching solution, maintaining the pH at 5.0 and the temperature at 45-65 ^o C, holding for 1-2 hours and filtering; and adding CuOH and Ni(OH) ₂ to the leaching solution, maintaining the pH at 2.5-4.8 and the temperature at 35-50 ^o C, holding for 1 hour, filtering and thus obtaining a pure electrolyte.

Thus, the invention relates to the field of metallurgical chemical industry technology, in particular to a method and application for purifying zinc oxide.

The disadvantages of the known technical solution compared to the declared technical solution are:

- impossibility of extracting zinc from waste;

- the impossibility of obtaining metallic iron by the method of direct reduction of iron;

- impossibility of de-oiling oily scale;

- the impossibility of using standard brick factory equipment such as a tunnel and/or chamber and/or ring, shaft kiln as high-temperature equipment;

- it is impossible to use standard brick factory equipment (tunnel and/or chamber and/or ring, shaft kiln) for cleaning zinc oxide from zinc halides;

- the impossibility of obtaining briquettes using standard brick factory equipment;

- the impossibility of combining high-temperature firing and drying of raw materials in one unit;

- low energy efficiency of equipment;

- the impossibility of using any type of carbon-containing reducing agent;

- absence of heat recovery from exhaust gases for heating air and drying briquettes;

- requires preliminary drying of raw materials before forming briquettes;

- does not allow the use of cooled flue gases, previously cleaned from zinc-containing dust, for cooling the recovered product;

- the absence of a system for the oxidation of exhaust gases to obtain zinc oxide and for the oxidation of the remaining components to higher oxides;

- does not allow obtaining dezincification products in the form of reduced iron mixed with a slag component, regulation of the basicity of the slag component;

- there is no possibility to regulate the degree of iron reduction;

- the impossibility of regulating the basicity of the slag component by adding alkaline sintering agents;

- does not apply to the development of a universal complex based on standard equipment for a ceramic brick production plant, which allows for the solution of all the listed problems in combination;

- the impossibility of forming briquettes with dimensions up to 350x350x350 mm;

- the use of briquettes that cannot be placed in the standard equipment of a ceramic brick production plant - a tunnel and/or chamber and/or ring and/or shaft furnace - without special equipment;

- the presence of contact between the raw material and the furnace lining, which leads to rapid wear and destruction of the lining;

- the impossibility of regulating the duration of the raw material's stay in firing zones or stages with different air/fuel ratios, in firing zones or stages with different degrees of reducing gas environment.

From the studied level of technology, the applicant has identified an invention according to Russian patent No. 2280087 "Method for processing zinc-containing dusts of electric arc furnaces". The essence is a method for processing zinc-containing dust of electric arc furnaces, including the operations of mixing, pelletizing, Waelz, hydrometallurgical processing of zinc-containing clinker, characterized in that the dust of electric arc furnaces is mixed before pelletizing with a material containing calcium oxide in an amount that ensures the addition of calcium oxide in an amount of 70-110% of the content of iron oxide (Fe2O3) in the dust, which is part of zinc ferrite (ZnO×Fe2O3), and coke in an amount of 1-2% by weight of the said dust.

Thus, the invention relates to metallurgy and can be used in the processing of zinc-containing dust from electric arc furnaces by Waelz furnaces.

The disadvantages of the known technical solution compared to the declared technical solution are:

- the impossibility of obtaining metallic iron by the method of direct reduction of iron;

- impossibility of de-oiling oily scale;

- the impossibility of using standard brick factory equipment, such as a tunnel, and/or chamber, and/or ring, shaft kiln, as high-temperature equipment;

- the impossibility of using standard brick factory equipment - a tunnel, and/or chamber, and/or ring shaft kiln - to purify zinc oxide from zinc halides;

- the impossibility of obtaining briquettes using standard brick factory equipment;

- the impossibility of combining high-temperature firing and drying of raw materials in one unit;

- low energy efficiency of equipment;

- the impossibility of using any type of carbon-containing reducing agent;

- absence of heat recovery from exhaust gases for heating air and drying briquettes;

- does not allow the use of cooled flue gases, previously cleaned from zinc-containing dust, for cooling the recovered product;

- the absence of a system for the oxidation of exhaust gases to obtain zinc oxide and for the oxidation of the remaining components to higher oxides;

- there is no possibility to regulate the degree of iron reduction;

- does not apply to the development of a universal complex based on standard equipment for a ceramic brick production plant, which allows for the solution of all the listed problems in combination;

- the impossibility of forming briquettes with dimensions up to 350x350x350 mm;

- the use of briquettes that cannot be placed in standard equipment of a ceramic brick production plant - a tunnel, and/or chamber, and/or ring, and/or shaft furnace without special equipment;

- the impossibility of regulating the duration of the raw material's stay in firing zones or stages with different air/fuel ratios, in firing zones or stages with different degrees of reducing gas environment;

- the presence of contact between the raw material and the furnace lining, which leads to rapid wear and destruction of the lining.

From the studied level of technology, the applicant has identified an invention under Russian patent No. 2082692 "Method for producing ceramic bricks". The essence is the preparation of a mixture of clay raw materials, a burnout additive and activated sludge, which is introduced in an amount of 10-50 wt. % on a dry substance in relation to the dry weight of the clay raw materials. Then the blank is formed, dried and fired. Activated sludge formed during the purification of municipal wastewater, or in the production of vitamin protein concentrates, or sludge from irrigation fields can be used.

Thus, the invention relates to the field of production of building products, in particular to the production of ceramic bricks.

The disadvantages of the known technical solution compared to the declared technical solution are:

- impossibility of extracting zinc from waste;

- the impossibility of obtaining metallic iron by the method of direct reduction of iron;

- impossibility of de-oiling oily scale;

- does not allow obtaining dezincification products in the form of reduced iron mixed with the slag component, regulation of the basicity of the slag component;

- there is no possibility to regulate the degree of iron reduction;

- the impossibility of regulating the basicity of the slag component by adding alkaline sintering agents.

From the studied level of technology, the applicant has identified an invention according to the patent of the Russian Federation No. 2052419 "Method for manufacturing bricks and ceramic stone". The essence is that the waste of coal flotation enrichment is divided into two parts, one of which in the amount of 10-20% of the total amount of waste is fed from a belt conveyor to a mixer, and the remaining part is poured onto another conveyor before feeding clay to the mixer, on which a layer of slag from metallurgical production is poured. The specified feeding of components ensures uniformity of the charge composition by volume. The composition of the charge includes, vol. %: waste of coal flotation enrichment 2-3, slag from metallurgical production 7-13, loam and/or clay - the rest. Slag from metallurgical production can be blast furnace, cupola, iron foundry and contain up to 40% CaO by weight. Bricks and ceramic stones are pressed at a specific pressure of 15-31 MPa and a moisture content of the press powder of 9-13%. Pressing can produce either solid bricks or bricks with holes and recesses. The shape of the products can be in the form of a non-equilateral polyhedron, a rectangular parallelepiped, a complex cylinder, a prism, etc. The openings in the bricks can be either through or closed at least at one end, and some of the openings can be made cylindrical at least over most of their length or with a cross-section in the form of an ellipse, or a polyhedron, or an oval, or a combined shape with sections of variable curvature and/or with flat inserts or in the form of their combinations. Moreover, the openings can be located in the body of the brick or stone in various ways. The recesses can also be made in various forms: a fragment of a sphere and/or spheroid, and/or ellipsoid, and/or paraboloid, and/or composite with surface areas of 4 - 2 orders of curvature. Brick, stone have a compressive strength of 26.3 - 27.5 MPa, a bending strength of 3.5 - 4.8 MPa, frost resistance over 100 cycles.

Thus, the invention relates to construction, production of building materials and is intended for the production of clay bricks and ceramic stones.

The disadvantages of the known technical solution compared to the declared technical solution are:

- impossibility of extracting zinc from waste;

- the impossibility of obtaining metallic iron by the method of direct reduction of iron;

- impossibility of de-oiling oily scale;

- does not allow obtaining dezincification products in the form of reduced iron mixed with the slag component, regulation of the basicity of the slag component;

- there is no possibility to regulate the degree of iron reduction;

- the impossibility of regulating the basicity of the slag component by adding alkaline sintering agents.

The level of technology identified by the applicant allows us to make a preliminary conclusion that known technical solutions do not allow us to resolve the full range of problems solved by the claimed technical solution, while a more detailed analysis of analogues is given in Table 3 in Fig. 3, in which the first row contains patent numbers and their names, and the first column presents the entire range of problems identified by the applicant, solved by analogous inventions, identified by the applicant from the level of technology examined on the date of submission of the application materials, which are aimed at solving the following problems.

An analysis of analogues allows us to conclude that they provide the ability to solve various problems only individually, but cannot solve the entire set of problems and technical results set out in the declared technical solution - in general, the applicant has detailed twenty-three basic problems for the method of processing iron-zinc-containing waste.

The fundamental technical results of the claimed invention are the development of a universal technology and a set of equipment that ensure the implementation on the same generally known standard equipment for the production of ceramic bricks (see Examples of specific implementation 1, 2, 3, 4, 5, 6, 7, 8, 9) with parameters of the process mode modified for the claimed technology, to solve a number of problems and obtain technical results, presented below in general.

• extraction of zinc from metallurgical waste,

• de-oiling of oily scale,

• obtaining direct reduced iron,

• purification of the obtained zinc oxide from halides,

• reduction of capital expenditures for the implementation of the process due to the use of a common and modified to perform the tasks of the declared method of standard equipment of a plant for the production of ceramic bricks, including a unit for the preparation and mixing of raw materials, a unit for the formation and drying of briquettes using standard equipment of a brick plant, a firing unit including a chamber and/or tunnel and/or ring and/or shaft furnace. Comparative data on capital expenditures for process units for the processing of iron-zinc-containing sludge with a capacity of 250-300 thousand tons / year by raw material are presented in Fig. 1, from which it can be concluded that the capital expenditures for the declared technical solution are significantly lower than the capital expenditures used on the date of submission of the declared materials for the processing of iron-zinc-containing waste.

The technical results of the declared technical solution as a whole are the obtaining of the above-mentioned results using standard equipment: the complex of such equipment is standard equipment and elements of well-known technology used by brick factories in the production of ceramic bricks.

At the same time, the declared technical solution allows for the processing of waste from ferrous and non-ferrous metallurgy in aggregate, including iron-zinc-containing sludge and dust, sludge and dust from converter production, sludge and dust from electric smelting production, blast furnace sludge and dust, oily scale, while the declared technology is characterized by the features of action on waste from ferrous and non-ferrous metallurgy as a whole, which are given below in more detail.

The declared technical solution is characterized by :

1. the ability to crush waste and solid reducing agent, binders and sintering agents to sizes less than 1 mm (this crushing equipment is part of the equipment of a standard ceramic brick plant);

2. the ability to dose components in accordance with the tasks to be solved (this equipment for dosing components is part of the equipment of a standard plant for producing ceramic bricks);

3. the possibility of mixing ingredients and cold forming briquettes using standard brick factory equipment (this equipment for mixing ingredients is also part of the equipment of a standard ceramic brick factory);

4. the ability to stack briquettes into piles, the dimensions of which allow for their loading into a tunnel, chamber, shaft or ring kiln, placing the pile on a trolley and feeding it into the briquette drying area (this equipment is part of the equipment of a standard ceramic brick manufacturing plant);

5. the ability to dry briquettes to a given strength, including using high-temperature firing equipment (this equipment is part of the equipment of a standard plant for producing ceramic bricks);

6. the ability to regulate the drying zone in order to achieve the highest strength indicators of the raw briquette (included in the equipment of a standard plant for the production of ceramic bricks);

7. the possibility of firing briquettes with a long residence time in a high-temperature zone, including in the flashing zone (the zone of a ring, shaft or tunnel firing kiln, or the firing stage in a chamber kiln with a low excess air ratio and a reducing atmosphere in a gas environment) (this equipment is also part of the equipment of a standard ceramic brick plant, and may differ depending on the type of kiln used in a particular brick plant);

8. the ability to regulate the duration of the raw material’s stay in firing zones or stages with different air/fuel ratios, in firing zones or stages with different degrees of reducing gas environment (this equipment is part of the equipment of a standard ceramic brick production plant);

9. the possibility of using high-temperature equipment for firing ceramic bricks, such as tunnel, chamber, ring, and shaft furnaces, in order to reduce operating and capital costs, which are also included in the equipment of a standard ceramic brick production plant;

10. the possibility of further oxidation of flue gases to higher oxides, including zinc oxide and carbon monoxide (this equipment is part of the equipment of a standard plant for the production of ceramic bricks);

11. the possibility of recovering heat from flue gases (this equipment is part of the equipment of a standard plant for the production of ceramic bricks);

12. the ability to clean flue gases from solid dust, including zinc compounds (included in the equipment of a standard plant for the production of ceramic bricks);

13. the possibility of cooling briquettes in various ways depending on the selected equipment (this equipment is part of the equipment of a standard plant for the production of ceramic bricks);

14. the possibility of calcining zinc oxide with impurities in order to remove zinc halides (this equipment is part of the equipment of a standard plant for the production of ceramic bricks);

15. the possibility of eliminating contact of raw materials and fired products with the furnace lining in order to avoid destruction of the lining; such a possibility is created in the method by changing the technological modes of the declared technical solution in terms of the method (i.e. technological modes), which differs significantly from the modes existing in standard factories for the production of ceramic bricks).

The technical results of the declared technical solution are:

1. extraction of zinc from waste;

2. obtaining metallic iron by direct reduction of iron;

3. de-oiling of oily scale;

4. reduction of capital costs for the implementation of the process due to the use of standard equipment of a plant for the production of ceramic bricks, including a unit for the preparation and mixing of raw materials, a unit for the formation and drying of briquettes using standard equipment of a brick plant, a firing unit, including a chamber and/or tunnel and/or ring and/or shaft kiln;

5. combination of high-temperature firing and additional drying of briquettes in one unit;

6. high energy efficiency of equipment with low heating rate and long stay in the high-temperature zone;

7. use of any type of carbon-containing reducing agent;

8. heat recovery from exhaust gases for heating air and drying briquettes

9. elimination of preliminary drying of raw materials before forming briquettes;

10. the possibility of regulating the duration of the raw material’s stay in the firing zones or stages with different air/fuel ratios and with different degrees of reducing gas environment.

11. to increase the yield of metallized iron and reduce secondary oxidation, use cooled flue gases, previously cleaned of zinc-containing dust, to cool the reduced product;

12. to improve environmental protection, additional oxidation of exhaust gases to obtain zinc oxide, and additional oxidation of the remaining components to higher oxides;

13. obtaining products in solid form, suitable for transportation by non-specialized transport, obtaining products of dezincification of raw materials and reduced iron, in the form of briquettes of any shape and required size;

14. obtaining dezincification products in the form of reduced iron mixed with a slag component, regulating the basicity of the slag component.

15. regulation of the degree of iron reduction;

16. regulation of the basicity of the slag component by adding alkaline sintering agents;

17. formation of briquettes with dimensions not exceeding 350x350x350 mm;

18. development of a universal complex based on standard equipment of a plant for the production of ceramic bricks, which allows for the solution of all the listed problems;

19. purification of zinc oxide from halides using a standard set of equipment at a ceramic brick manufacturing plant;

20. the use of briquettes that cannot be placed in standard equipment of a ceramic brick production plant – a tunnel, and/or chamber, and/or ring, and/or shaft furnace without special equipment;

21. eliminating contact of raw materials with the furnace lining to avoid destruction of the lining;

22. increasing the recovery time to reduce the final process temperature;

23. elimination of low service life between repairs and long manufacturing time of replacement parts of the matrix press.

The essence of the claimed technical solution is a method for processing iron-containing raw materials, zinc-containing raw materials, iron-zinc-containing waste from metallurgical production, including zinc-containing sludge and dust, sludge and dust from converter production, sludge and dust from electric smelting production, blast furnace sludge and dust, oily scale, allowing for the production of direct reduction iron, dezincification of raw materials, deoiling of oily scale, isolation of zinc in the form of oxide and zinc salts, consisting in the fact that during the processing, waste and solid reducing agent are stored, then the waste and solid reducing agent, binding and sintering agents are crushed to sizes less than 1 mm, the quantitative composition of the waste is analyzed to calculate the stoichiometric amount of the required pure carbon of the reducing agent used to reduce iron and zinc, depending on their content in iron-zinc-containing sludge, then the ingredients are dosed, iron-zinc-containing sludge, oily scale, solid reducing agent from the series coal, coke, coke, coal fines and dust in terms of pure carbon no more than 110% of the stoichiometrically required for the reduction of iron and zinc; when the content of iron oxides in iron-zinc-containing sludge is more than 85%, alkaline sintering agents from the series oxides and carbonates of calcium and magnesium are added to the mixture in a stoichiometric ratio; then add a mineral binder required for cold briquette formation, from the series: cement, bentonite, lime, liquid glass, then: mix waste, reducing agent, sintering binder, binder for cold briquette formation, dose water to a mixture consistency allowing the briquette to be formed by extrusion or pressing, then form briquettes, then stack the briquettes into piles, the dimensions of which allow it to be loaded into a tunnel, chamber, shaft or ring kiln, place the pile on a trolley and feed it into the briquette drying zone, then dry the briquettes in the pile with air or purified flue gases, while the drying process is carried out in a separate unit in the drying chamber, while the drying of the briquettes can be combined with the firing process in one apparatus, then fire the briquettes in the pile in the firing furnace, while the composition flue gases formed during fuel combustion are reducing in the main firing zone, whereby iron and zinc are reduced, and the reduced zinc evaporates from the briquettes at the firing temperature, passing into the gas phase and is transferred by the flue gases to the flue gas post-oxidation zone, then the flue gases are further oxidized in order to oxidize CO and zinc to higher oxides, whereby in the flue gas post-oxidation unit and in the flue gas outlet zone from the firing chamber the flue gas composition must be oxidizing, for the post-oxidation of CO to CO2 and zinc vapor to zinc oxide, post-oxidation is carried out by feeding an additional amount of air into this zone; The recovered zinc evaporates from the briquettes at the firing temperature into the gas phase and is transferred by the flue gases to the flue gas oxidation zone, where it is oxidized to zinc oxide, then the flue gases are cooled in recuperative heat exchangers, then the flue gases are cleaned of solid dust - zinc compounds, dust in the filter unit, then the briquettes are cooled in the stack.

The claimed technical solution is illustrated in Fig.1 – Fig.5.

Fig. 1 shows Table 1, which provides comparative data on capital costs for process units for processing iron-zinc-containing sludge with a capacity of 250-300 thousand tons/year of raw materials.

Fig. 2 shows Table 2, which shows the chemical composition of the mixture of iron-zinc-containing waste, the products obtained from the stage of iron reduction and zinc removal, and the purification of zinc oxide from halides according to examples 1-9.

Fig. 3 shows Table 3, which provides a comparative analysis of the problems solved by various known patents in comparison with the claimed technical solution.

Fig. 4 shows a block diagram proposed by the applicant, which allows for the extraction of zinc from waste, the production of metallic iron by direct reduction of iron, deoiling of oily scale, dezincification of raw materials and the isolation of zinc compounds.

Fig. 5 shows a block diagram of element 11 of Fig. 4, proposed by the applicant, which allows for the purification of isolated zinc compounds from zinc halides.

The applicant then provides a description of the claimed technical solution.

To solve the set tasks and achieve the stated technical result, a technology and a universal set of equipment have been developed that allow for the combined processing of ferrous and non-ferrous metallurgy waste, including iron-zinc-containing sludge and dust, converter production sludge and dust, electric smelting production sludge and dust, blast furnace sludge and dust, and oily scale.

The claimed technology and universal equipment complex (claimed group of inventions) allows for the extraction of zinc from waste, the production of metallic iron by direct reduction of iron, and the deoiling of oily scale.

The applicant further provides a set of equipment for implementing the claimed method.

The declared equipment complex includes: a raw material preparation and mixing unit, a briquette formation and drying unit, a briquette firing unit, an afterburning and flue gas cleaning unit, wherein the briquette firing zone is designed with the ability to ensure an excess air to fuel ratio of less than 1 by creating a reducing environment in the gas flow of fuel combustion products.

Further, the applicant presents a detailed sequence of actions of the declared method , with a detailed description of each of the stages of the declared method, depending on both the types of waste and the tasks set by the user of the declared technical solution:

1. Carry out storage of waste (iron-containing, zinc-containing, iron-zinc-containing sludge and dust, oily scale) and solid reducing agent (coke, coal of various grades, coke fines, coal fines, coconut dust, coal dust);

2. Perform grinding of waste and solid reducing agent, binders and sintering agents to sizes less than 1 mm;

3. Perform an analysis of the quantitative composition of waste using known methods to calculate the stoichiometric amount of the required pure carbon - a reducing agent used to reduce iron and zinc, depending on their content in iron-zinc-containing sludge.

4. Next, the ingredients are dosed, for which the following are added to the mixture:

– iron-zinc-containing sludge, oily scale;

– solid reducing agent (coal, coke, coke, coal fines and dust, and other carbon-containing products) in terms of pure carbon – no more than 110% of the stoichiometrically required amount for the reduction of iron and zinc (exceeding the amount of solid reducing agent reduces the economic performance of the process);

– if the iron-zinc-containing sludge contains a high amount of iron oxides – more than 85%, alkaline sintering agents – oxides and carbonates of calcium and magnesium – are added to the mixture (an excess of iron oxides in the sludge leads to a decrease in the strength of the briquettes);

- add a mineral binder required for cold briquette formation from the following series: cement, bentonite, lime, liquid glass, in an amount of no more than 7% of the sum of the mass of iron-zinc-containing sludge and solid reducing agent. (exceeding the amount of mineral binder reduces the economic performance of the process);

– further actions are carried out according to several specific implementation options (4.1 – 4.5) depending on the set of tasks set by the user from the series:

1 – extraction of zinc from waste,

2 – obtaining metallic iron by direct reduction of iron,

3 – de-oiling of oily scale,

4 – combination of tasks performed,

then the dosing of components is carried out in the following variants :

Option 4.1: to solve three problems (1, 2, 3) – extracting zinc from waste, obtaining metallic iron and deoiling oily scale, the following are added to the mixture:

- iron-zinc-containing sludge,

- oily scale,

– solid reducing agent (coal, coke, coke, coal fines and dust, and other carbon-containing products) in terms of pure carbon no more than 110% of the stoichiometric amount required for the reduction of iron and zinc (exceeding the amount of solid reducing agent reduces the economic performance of the process),

– with a high content of iron oxides in iron-zinc-containing sludges – more than 85%, alkaline sintering agents are added to the mixture – oxides and carbonates of calcium and magnesium (an excess of iron oxides in the sludge leads to a decrease in the strength of the briquettes),

– add a mineral binder necessary for cold briquette formation, from the following series: cement, bentonite, lime, liquid glass in an amount of no more than 7% of the sum of the mass of iron-zinc-containing sludge and solid reducing agent (exceeding the amount of mineral binder reduces the economic performance of the process);

Option 4.2: to solve two problems (1, 2) – extracting zinc from waste and obtaining metallic iron, the following is introduced into the mixture:

- iron-zinc-containing sludge,

– solid reducing agent (coal, coke, coke, coal fines and dust, and other carbon-containing products) in terms of pure carbon no more than 110% of the stoichiometric amount required for the reduction of iron and zinc (exceeding the amount of solid reducing agent reduces the economic performance of the process),

– if the iron-zinc sludge contains a high amount of iron oxides – more than 85%, alkaline sintering agents – oxides and carbonates of calcium and magnesium – are added to the mixture (an excess of iron oxides in the sludge leads to a decrease in the strength of the briquettes),

– add a mineral binder necessary for cold briquette formation from the following series: cement, bentonite, lime, liquid glass in an amount of no more than 7% of the sum of the mass of iron-zinc-containing sludge and solid reducing agent (exceeding the amount of mineral binder reduces the economic performance of the process);

Option 4.3: to solve one problem (1) – extracting zinc from waste without obtaining metallic iron, the following is introduced into the mixture:

- iron-zinc-containing sludge,

– solid reducing agent (coal, coke, coke, coal fines and dust, and other carbon-containing products) in terms of pure carbon no more than 110% of the stoichiometric amount required for zinc reduction (exceeding the amount of solid reducing agent reduces the economic performance of the process),

– if the iron-zinc sludge contains a high amount of iron oxides – more than 85%, alkaline sintering agents – oxides and carbonates of calcium and magnesium – are added to the mixture (an excess of iron oxides in the sludge leads to a decrease in the strength of the briquettes),

– add a mineral binder necessary for cold briquette formation from the following series: cement, bentonite, lime, liquid glass in an amount of no more than 7% of the sum of the mass of iron-zinc-containing sludge and solid reducing agent (exceeding the amount of mineral binder reduces the economic performance of the process);

Option 4.4 : to solve two problems (1, 3) – extracting zinc from waste and deoiling oily scale without obtaining metallic iron, the following is introduced into the mixture:

- solid reducing agent (coal, coke, coke, coal fines and dust and other carbon-containing products) in terms of pure carbon no more than 110% of the stoichiometrically required for zinc reduction. Exceeding the amount of solid reducing agent reduces the economic indicators of the process

– if the iron-zinc sludge contains a high amount of iron oxides – more than 85%, alkaline sintering agents – oxides and carbonates of calcium and magnesium – are added to the mixture (an excess of iron oxides in the sludge leads to a decrease in the strength of the briquettes),

– add a mineral binder necessary for cold briquette formation, from the following series: cement, bentonite, lime, liquid glass in an amount of no more than 7% of the sum of the mass of iron-zinc-containing sludge and solid reducing agent (exceeding the amount of mineral binder reduces the economic performance of the process);

Option 4.5 : to solve one problem (3) – de-oiling of oily scale, the following is introduced into the mixture:

– oily scale and slag components – calcium oxide, magnesium oxide, silicon oxide, etc.,

– if the iron-zinc sludge contains a high amount of iron oxides – more than 85%, alkaline sintering agents – oxides and carbonates of calcium and magnesium – are added to the mixture (an excess of iron oxides in the sludge leads to a decrease in the strength of the briquettes),

– add a mineral binder necessary for cold briquette formation, from the following series: cement, bentonite, lime, liquid glass in an amount of no more than 7% of the sum of the mass of iron-zinc-containing sludge and solid reducing agent (exceeding the amount of mineral binder reduces the economic performance of the process).

5. Next, for all types of compositions, perform:

– mixing of waste, reducing agent, then sintering binder, then binder for cold briquette formation,

– dosing water to a mixture consistency that allows the formation of a briquette by extrusion or pressing;

6. Next, the briquettes are formed using known methods, such as extrusion, pressing, and vibration pressing.

7. Next, the briquettes are stacked into piles the dimensions of which allow them to be loaded into a tunnel, chamber, shaft or ring kiln, the piles are placed on a trolley and fed into the briquette drying area.

8. Next, the briquettes are dried in a stack using air or purified flue gases, and the drying process is carried out in a separate unit in a drying chamber, and the drying of the briquettes can be combined with the firing process in one apparatus.

9. Next, the briquettes are fired in a stack in a firing furnace (in a tunnel, chamber or ring, shaft furnace). In this case, the composition of the flue gases formed during combustion of the fuel (solid, liquid or gaseous) is reducing in the main firing zone (since the flue gases do not contain oxygen and contain the maximum amount of CO). In this case, iron and zinc are reduced, and the reduced zinc evaporates from the briquettes at the firing temperature, passing into the gas phase and is transferred by the flue gases to the flue gas oxidation zone.

10. Next, the flue gases undergo post-oxidation to oxidize CO and zinc to higher oxides. In this case, in the flue gas post-oxidation unit and in the flue gas outlet zone from the firing chamber, the flue gas composition must be oxidizing; for post-oxidation of CO to _CO2 and zinc vapor to zinc oxide, post-oxidation is carried out by feeding an additional amount of air into this zone. Reduced zinc evaporates from the briquettes at the firing temperature into the gas phase and is transferred by flue gases to the flue gas post-oxidation zone, where it is oxidized to zinc oxide (ZnO).

11. Next, the flue gases are cooled in recuperative heat exchangers;

12. Next, the flue gases are cleaned of solid dust (zinc compounds, dust) in the filter unit;

13. Next, the briquettes are cooled in the stack, and the actions are carried out according to several specific implementation options (13.1 – 13.5) depending on the set of tasks set by the user:

– option 13.1: cooling of the stack of briquettes after the firing process is performed using the wet method, using water as a cooling agent;

– option 13.2: cooling of the stack of briquettes after the firing process is performed using a dry method using air as a cooling agent;

– option 13.3: cooling of the stack of briquettes after the process of roasting and reduction of iron and zinc is carried out in a dry way, cooled after heat recovery by purified and cooled flue gases; cooling by flue gases is provided to reduce secondary oxidation of iron;

– option 13.4: cooling of the stack of briquettes after the firing process is carried out using a combined method, by injecting sprayed water into the cooling gas flow;

– option 13.5: performed without cooling – the briquettes are transported hot after firing to recover heat in subsequent metallurgical processes (using transport whose cargo platform is equipped with thermal insulation).

14. Next, zinc oxide is purified from impurities (zinc halides) in a separate firing furnace or in the same firing equipment (in a tunnel, chamber or ring, shaft furnace) used for firing and sintering briquettes, while firing takes at least 2 hours, with the possibility of ensuring economical fuel consumption, while zinc halides evaporate at the firing temperature into the gas phase, flue gases are cooled in recuperative heat exchangers, then the flue gases are purified from solid dust - zinc halides in the filter unit, and zinc oxide, purified from halides, is cooled. The mixture of zinc compounds is placed in the firing furnace in ceramic crucibles of a size that allows placement in the firing zone or in the form of briquettes.

Further actions are carried out according to several specific implementation options (14.1 – 14.2) depending on the set of tasks set by the user:

– option 14.1 : the resulting mixture of zinc compounds is placed in a firing furnace in ceramic crucibles of a size that allows them to be placed in the firing zone, in a tunnel, chamber or ring, shaft furnace, while the firing takes place for at least 2 hours, with the possibility of ensuring economical fuel consumption, while zinc halides evaporate at the firing temperature into the gas phase, the flue gases are cooled in recuperative heat exchangers, then the flue gases are cleaned of solid dust - zinc halides in the filter unit, and zinc oxide, cleaned of halides, is cooled.

– option 14.2 : the resulting mixture of zinc compounds is placed in a firing furnace in the form of briquettes, for this purpose the mixture of zinc compounds is mixed with a binder for cold briquette formation, water is dosed to the consistency of the mixture allowing the briquette to be formed by extrusion or pressing, then the briquettes are formed by extrusion or pressing, after which the briquettes are stacked in piles the dimensions of which allow them to be loaded into a tunnel, chamber, shaft or annular firing furnace, the piles are placed on a trolley and fed to the briquette drying zone, while the briquettes are dried in a pile with air or purified flue gases, and the drying process can be carried out in a separate unit in a drying chamber or combined with the firing process in a single firing apparatus in a pile of briquettes of a tunnel, chamber or annular, shaft furnace. For economical fuel consumption, the process of roasting and sintering of briquettes should last at least 2 hours. Zinc halides evaporate from the briquettes at the roasting temperature into the gas phase. Flue gases are cooled in recuperative heat exchangers. Flue gases are cleaned from solid dust (zinc halides) in the filter unit. Zinc oxide briquettes cleaned from halides are cooled.

Fig. 4 shows a block diagram proposed by the applicant, which allows for the extraction of zinc from waste, the production of metallic iron by direct reduction of iron, deoiling of oily scale, dezincification of raw materials and the isolation of zinc compounds.

Fig. 5 shows a block diagram proposed by the applicant, which allows for the purification of isolated zinc compounds from zinc halides.

Further, the applicant provides examples of the implementation of the declared technical solution with different batch compositions and waste ratios.

Example 1.

Preparation for processing. Take a mixture of iron-zinc-containing waste, which consists of the following components: electric steelmaking shop (ESPS) sludge - 14%, converter production sludge - 63%, blast furnace production - 14%, oily scale - 9%. Solid reducing agent (coal, coke, coke, coal fines and dust and other carbon-containing products) is taken in terms of pure carbon no more than 110% of the stoichiometrically required for zinc reduction. Binder - bentonite - is taken 4% of the sum of the mass of iron-zinc-containing sludge and solid reducing agent. The chemical composition of the mixture of iron-zinc-containing waste is shown in Table 2 in Fig. 2.

The process of recovery of iron-zinc-containing waste is carried out according to the block diagram, which is presented in Fig. 4, and consists of the following stages: storage of waste and carbon-containing reducing agent; crushing is performed to a size of less than 1 mm, dosing, mixing of waste and carbon-containing reducing agent, binding sintering agents; molding of briquettes; stacking of briquettes in piles; drying of briquettes in a pile with air or purified flue gases; firing in a pile of briquettes at a temperature of 1050 °C, wherein in the firing zone of the briquettes a reducing environment is created in the gas flow of fuel combustion products, by ensuring an excess air to fuel coefficient of less than 1; cooling of briquettes in a pile; afterburning of flue gases, cooling of flue gases, purification of flue gases from zinc compounds.

The process of additional purification of zinc oxide from halides is carried out according to the block diagram, which is presented in Fig. 5, and consists of the following stages: mixing zinc oxide with impurities with a binding sintering agent; molding of briquettes; stacking of briquettes in stacks; drying of briquettes in a stack with air or purified flue gases; firing in a stack of briquettes at a temperature of 1050 °C, since at lower temperatures evaporation of zinc halides does not occur; cooling of briquettes in a stack; afterburning of flue gases, cooling of flue gases, purification of flue gases from zinc halides.

The composition of the obtained products of the stage of reduction and purification of zinc oxide from impurities is presented in Table 2, Fig. 2.

Example 2.

Preparation for processing. Take a mixture of iron-zinc-containing waste, which consists of the following components: slag components 30%, oily scale 70%. Solid reducing agent (coal, coke, coke, coal fines and dust and other carbon-containing products) is taken in terms of pure carbon no more than 110% of the stoichiometrically required for zinc reduction. Binder - liquid glass - is taken 7% of the sum of the mass of iron-zinc-containing sludge and solid reducing agent. The chemical composition of the mixture of iron-zinc-containing waste is shown in Table 2 Fig. 2.

The process of recovery of iron-zinc-containing waste is carried out according to the block diagram, which is shown in Fig. 4 and consists of the following stages: storage of waste and carbon-containing reducing agent; crushing is performed to a size of less than 1 mm, dosing, mixing of waste and carbon-containing reducing agent, binding sintering agents; molding of briquettes; stacking of briquettes in piles; drying of briquettes in a pile with air or purified flue gases; firing in a pile of briquettes at a temperature of 980 °C, wherein in the firing zone of the briquettes a reducing environment is created in the gas flow of fuel combustion products, by ensuring an excess air to fuel coefficient of less than 1; cooling of briquettes in a pile; afterburning of flue gases, cooling of flue gases, purification of flue gases from zinc compounds.

The process of additional purification of zinc oxide from halides is carried out according to the block diagram, which is presented in Fig. 5 and consists of the following stages: mixing zinc oxide with impurities with a binding sintering agent; molding of briquettes; stacking of briquettes in stacks; drying of briquettes in a stack with air or purified flue gases; firing in a stack of briquettes at a temperature of 980 °C, since at lower temperatures evaporation of zinc halides does not occur; cooling of briquettes in a stack; afterburning of flue gases, cooling of flue gases, purification of flue gases from zinc halides.

The composition of the obtained products of the recovery stage is shown in Table 2, Fig. 2.

Example 3.

Preparation for processing. Take a mixture of iron-zinc-containing waste, which consists of the following components: electric steelmaking shop (ESPS) sludge - 19%, converter production sludge - 59%, blast furnace production - 22%. Solid reducing agent (coal, coke, coke, coal fines and dust and other carbon-containing products) is taken in terms of pure carbon no more than 110% of the stoichiometrically required for zinc reduction. Binder - cement - is taken 5% of the sum of the mass of iron-zinc-containing sludge and solid reducing agent. The chemical composition of the mixture of iron-zinc-containing waste is presented in Table 2 Fig. 2.

The process of recovery of iron-zinc-containing waste is carried out according to the block diagram, which is shown in Fig. 4 and consists of the following stages: storage of waste and carbon-containing reducing agent; crushing is performed to a size of less than 1 mm, dosing, mixing of waste and carbon-containing reducing agent, binding sintering agents; molding of briquettes; stacking of briquettes in piles; drying of briquettes in a pile with air or purified flue gases; firing in a pile of briquettes at a temperature of 1030 °C, wherein in the firing zone of the briquettes a reducing environment is created in the gas flow of fuel combustion products, by ensuring an excess air to fuel coefficient of less than 1; cooling of briquettes in a pile; afterburning of flue gases, cooling of flue gases, purification of flue gases from zinc compounds.

The process of additional purification of zinc oxide from halides is carried out according to the block diagram, which is presented in Fig. 5 and consists of the following stages: mixing zinc oxide with impurities with a binding sintering agent; molding of briquettes; stacking of briquettes in stacks; drying of briquettes in a stack with air or purified flue gases; firing in a stack of briquettes at a temperature above 1030°C, since at lower temperatures evaporation of zinc halides does not occur; cooling of briquettes in a stack; afterburning of flue gases, cooling of flue gases, purification of flue gases from zinc halides.

The composition of the obtained products of the stage of reduction and purification of zinc oxide from impurities is presented in Table 2, Fig. 2.

Example 4.

Preparation for processing. Take a mixture of iron-zinc-containing waste, which consists of the following components: electric steelmaking shop (ESPS) sludge - 15%, converter production sludge - 20%, blast furnace production - 47%, oily scale - 18%. Solid reducing agent (coal, coke, coke, coal fines and dust, and other carbon-containing products) is taken in terms of pure carbon no more than 110% of the stoichiometrically required for zinc reduction. Binder - bentonite - is taken 6% of the sum of the mass of iron-zinc-containing sludge and solid reducing agent. The chemical composition of the mixture of iron-zinc-containing waste is shown in Table 2 Fig. 2.

The process of recovery of iron-zinc-containing waste is carried out according to the block diagram, which is shown in Fig. 4 and consists of the following stages: storage of waste and carbon-containing reducing agent; crushing is performed to a size of less than 1 mm, dosing, mixing of waste and carbon-containing reducing agent, binding sintering agents; molding of briquettes; stacking of briquettes in piles; drying of briquettes in a pile with air or purified flue gases; firing in a pile of briquettes at a temperature of 1400 °C, wherein in the firing zone of the briquettes a reducing environment is created in the gas flow of fuel combustion products, by ensuring an excess air to fuel coefficient of less than 1; cooling of briquettes in a pile; afterburning of flue gases, cooling of flue gases, purification of flue gases from zinc compounds.

The process of additional purification of zinc oxide from halides is carried out according to the block diagram, which is presented in Fig. 5 and consists of the following stages: mixing zinc oxide with impurities with a binding sintering agent; molding of briquettes; stacking of briquettes in stacks; drying of briquettes in a stack with air or purified flue gases; firing in a stack of briquettes at a temperature of 1400 °C, since at lower temperatures evaporation of zinc halides does not occur; cooling of briquettes in a stack; afterburning of flue gases, cooling of flue gases, purification of flue gases from zinc halides.

The composition of the obtained products of the stage of reduction and purification of zinc oxide from impurities is presented in Table 2, Fig. 2.

Example 5.

Preparation for processing. Take a mixture of iron-zinc-containing waste, which consists of the following components: electric steelmaking shop (ESPS) sludge - 17%, converter production sludge - 72%, oily scale - 11%. Solid reducing agent (coal, coke, coke, coal fines and dust, and other carbon-containing products) is taken in terms of pure carbon no more than 110% of the stoichiometrically required for zinc reduction. Binder - cement - is taken 4% of the sum of the mass of iron-zinc-containing sludge and solid reducing agent. The chemical composition of the mixture of iron-zinc-containing waste is shown in Table 2 Fig. 2.

The process of recovery of iron-zinc-containing waste is carried out according to the block diagram, which is shown in Fig. 4 and consists of the following stages: storage of waste and carbon-containing reducing agent; crushing is performed to a size of less than 1 mm, dosing, mixing of waste and carbon-containing reducing agent, binding sintering agents; molding of briquettes; stacking of briquettes in piles; drying of briquettes in a pile with air or purified flue gases; firing in a pile of briquettes at a temperature of 1210 °C, wherein in the firing zone of the briquettes a reducing environment is created in the gas flow of fuel combustion products, by ensuring an excess air to fuel coefficient of less than 1; cooling of briquettes in a pile; afterburning of flue gases, cooling of flue gases, purification of flue gases from zinc compounds.

The process of additional purification of zinc oxide from halides is carried out according to the block diagram, which is presented in Fig. 5 and consists of the following stages: mixing zinc oxide with impurities with a binding sintering agent; molding of briquettes; stacking of briquettes in stacks; drying of briquettes in a stack with air or purified flue gases; firing in a stack of briquettes at a temperature of 1210 °C, since at lower temperatures evaporation of zinc halides does not occur; cooling of briquettes in a stack; afterburning of flue gases, cooling of flue gases, purification of flue gases from zinc halides.

The composition of the obtained products of the stage of reduction and purification of zinc oxide from impurities is presented in Table 2, Fig. 2.

Example 6.

Preparation for processing. Take a mixture of iron-zinc-containing waste, which consists of the following components: electric steelmaking shop (ESPS) sludge - 13%, converter production sludge - 29%, blast furnace production - 53%, oily scale - 5%. Solid reducing agent (coal, coke, coke, coal fines and dust and other carbon-containing products) is taken in terms of pure carbon no more than 110% of the stoichiometrically required for zinc reduction. Binder - liquid glass - is taken 6% of the sum of the mass of iron-zinc-containing sludge and solid reducing agent. The chemical composition of the mixture of iron-zinc-containing waste is shown in Table 2 Fig. 2.

The process of recovery of iron-zinc-containing waste is carried out according to the block diagram, which is shown in Fig. 4 and consists of the following stages: storage of waste and carbon-containing reducing agent; crushing is performed to a size of less than 1 mm, dosing, mixing of waste and carbon-containing reducing agent, binding sintering agents; molding of briquettes; stacking of briquettes in piles; drying of briquettes in a pile with air or purified flue gases; firing in a pile of briquettes at a temperature of 990 °C, wherein in the firing zone of the briquettes a reducing environment is created in the gas flow of fuel combustion products, by ensuring an excess air to fuel coefficient of less than 1; cooling of briquettes in a pile; afterburning of flue gases, cooling of flue gases, purification of flue gases from zinc compounds.

The process of additional purification of zinc oxide from halides is carried out according to the block diagram, which is presented in Fig. 5 and consists of the following stages: mixing zinc oxide with impurities with a binding sintering agent; molding of briquettes; stacking of briquettes in stacks; drying of briquettes in a stack with air or purified flue gases; firing in a stack of briquettes at a temperature of 990°C, since at lower temperatures evaporation of zinc halides does not occur; cooling of briquettes in a stack; afterburning of flue gases, cooling of flue gases, purification of flue gases from zinc halides.

The composition of the obtained products of the stage of reduction and purification of zinc oxide from impurities is presented in Table 2, Fig. 2.

Example 7.

Preparation for processing. Take a mixture of iron-zinc-containing waste, which consists of the following components: electric steelmaking shop (ESPS) sludge - 13%, converter production sludge - 50%, blast furnace production - 37%. Solid reducing agent (coal, coke, coke, coal fines and dust and other carbon-containing products) is taken in terms of pure carbon no more than 110% of the stoichiometrically required for zinc reduction. Binder - cement - is taken 4% of the sum of the mass of iron-zinc-containing sludge and solid reducing agent. The chemical composition of the mixture of iron-zinc-containing waste is shown in Table 2 Fig. 2.

The process of recovery of iron-zinc-containing waste is carried out according to the block diagram, which is shown in Fig. 4 and consists of the following stages: storage of waste and carbon-containing reducing agent; crushing is performed to a size of less than 1 mm, dosing, mixing of waste and carbon-containing reducing agent, binding sintering agents; molding of briquettes; stacking of briquettes in piles; drying of briquettes in a pile with air or purified flue gases; firing in a pile of briquettes at a temperature of 900 °C, wherein in the firing zone of the briquettes a reducing environment is created in the gas flow of fuel combustion products, by ensuring an excess air to fuel coefficient of less than 1; cooling of briquettes in a pile; afterburning of flue gases, cooling of flue gases, purification of flue gases from zinc compounds.

The process of additional purification of zinc oxide from halides is carried out according to the block diagram, which is presented in Fig. 5 and consists of the following stages: mixing zinc oxide with impurities with a binding sintering agent; molding of briquettes; stacking of briquettes in stacks; drying of briquettes in a stack with air or purified flue gases; firing in a stack of briquettes at a temperature of 900 °C, since at lower temperatures evaporation of zinc halides does not occur; cooling of briquettes in a stack; afterburning of flue gases, cooling of flue gases, purification of flue gases from zinc halides.

The composition of the obtained products of the stage of reduction and purification of zinc oxide from impurities is presented in Table 2, Fig. 2.

Example 8.

Preparation for processing. Take a mixture of iron-zinc-containing waste, which consists of the following components: electric steelmaking shop (ESPS) sludge - 3%, converter production sludge - 28%, blast furnace production - 47%, oily scale - 22%. Solid reducing agent (coal, coke, coke, coal fines and dust and other carbon-containing products) is taken in terms of pure carbon no more than 110% of the stoichiometrically required for zinc reduction. Binder - bentonite - is taken 6% of the sum of the mass of iron-zinc-containing sludge and solid reducing agent. The chemical composition of the mixture of iron-zinc-containing waste is shown in Table 2 Fig. 2.

The process of recovery of iron-zinc-containing waste is carried out according to the block diagram, which is shown in Fig. 4 and consists of the following stages: storage of waste and carbon-containing reducing agent; crushing is performed to a size of less than 1 mm, dosing, mixing of waste and carbon-containing reducing agent, binding sintering agents; molding of briquettes; stacking of briquettes in piles; drying of briquettes in a pile with air or purified flue gases; firing in a pile of briquettes at a temperature of 1350 °C, wherein in the firing zone of the briquettes a reducing environment is created in the gas flow of fuel combustion products, by ensuring an excess air to fuel coefficient of less than 1; cooling of briquettes in a pile; afterburning of flue gases, cooling of flue gases, purification of flue gases from zinc compounds.

The process of additional purification of zinc oxide from halides is carried out according to the block diagram, which is presented in Fig. 5 and consists of the following stages: mixing zinc oxide with impurities with a binding sintering agent; molding of briquettes; stacking of briquettes in stacks; drying of briquettes in a stack with air or purified flue gases; firing in a stack of briquettes at a temperature of 1350 °C, since at lower temperatures evaporation of zinc halides does not occur; cooling of briquettes in a stack; afterburning of flue gases, cooling of flue gases, purification of flue gases from zinc halides.

The composition of the obtained products of the reduction stage is presented in Table 2, Fig. 2.

Example 9.

Preparation for processing. Take a mixture of iron-zinc-containing waste, which consists of the following components: electric steelmaking shop (ESPS) sludge - 8%, converter production sludge - 50%, blast furnace production - 39%, oily scale - 3%. Solid reducing agent (coal, coke, coke, coal fines and dust and other carbon-containing products) is taken in terms of pure carbon no more than 110% of the stoichiometrically required for zinc reduction. Binder - liquid glass - is taken 7% of the sum of the mass of iron-zinc-containing sludge and solid reducing agent. The chemical composition of the mixture of iron-zinc-containing waste is shown in Table 2 Fig. 2.

The process of recovery of iron-zinc-containing waste is carried out according to the block diagram, which is shown in Fig. 4 and consists of the following stages: storage of waste and carbon-containing reducing agent; crushing is performed to a size of less than 1 mm, dosing, mixing of waste and carbon-containing reducing agent, binding sintering agents; molding of briquettes; stacking of briquettes in piles; drying of briquettes in a pile with air or purified flue gases; firing in a pile of briquettes at a temperature of 960 °C, wherein in the firing zone of the briquettes a reducing environment is created in the gas flow of fuel combustion products, by ensuring an excess air to fuel coefficient of less than 1; cooling of briquettes in a pile; afterburning of flue gases, cooling of flue gases, purification of flue gases from zinc compounds.

The process of additional purification of zinc oxide from halides is carried out according to the block diagram, which is presented in Fig. 5 and consists of the following stages: mixing zinc oxide with impurities with a binding sintering agent; molding of briquettes; stacking of briquettes in stacks; drying of briquettes in a stack with air or purified flue gases; firing in a stack of briquettes at a temperature of 960°C, since at lower temperatures evaporation of zinc halides does not occur; cooling of briquettes in a stack; afterburning of flue gases, cooling of flue gases, purification of flue gases from zinc halides.

The composition of the obtained products of the stage of reduction and purification of zinc oxide from impurities is presented in Table 2, Fig. 2.

From the above, it can be concluded that the applicant has achieved the stated technical result , namely: a method for processing iron-zinc-containing waste from metallurgical production and a set of equipment for implementing the method have been developed, which make it possible to achieve:

1. extraction of zinc from waste;

2. obtaining metallic iron by direct reduction of iron;

3. de-oiling of oily scale;

4. reduction of capital costs for the implementation of the process due to the use of standard equipment of a plant for the production of ceramic bricks, including a unit for the preparation and mixing of raw materials, a unit for the formation and drying of briquettes using standard equipment of a brick plant, a firing unit, including a chamber and/or tunnel and/or ring and/or shaft kiln;

5. combination of high-temperature firing and additional drying of briquettes in one unit;

6. high energy efficiency of equipment with low heating rate and long stay in the high-temperature zone;

7. use of any type of carbon-containing reducing agent;

8. heat recovery from exhaust gases for heating air and drying briquettes

9. elimination of preliminary drying of raw materials before forming briquettes;

10. the possibility of regulating the duration of the raw material’s stay in the firing zones or stages with different air/fuel ratios and with different degrees of reducing gas environment.

11. to increase the yield of metallized iron and reduce secondary oxidation, use cooled flue gases, previously cleaned of zinc-containing dust, to cool the reduced product;

12. to improve environmental protection, additional oxidation of exhaust gases to obtain zinc oxide, and additional oxidation of the remaining components to higher oxides;

13. obtaining products in solid form, suitable for transportation by non-specialized transport, obtaining products of dezincification of raw materials and reduced iron, in the form of briquettes of any shape and required size;

14. obtaining dezincification products in the form of reduced iron mixed with a slag component, regulating the basicity of the slag component.

15. regulation of the degree of iron reduction;

16. regulation of the basicity of the slag component by adding alkaline sintering agents;

17. formation of briquettes with dimensions not exceeding 350x350x350 mm;

18. development of a universal complex based on standard equipment of a plant for the production of ceramic bricks, which allows for the solution of all the listed problems;

19. purification of zinc oxide from halides using a standard set of equipment at a ceramic brick manufacturing plant;

20. the use of briquettes that cannot be placed in standard equipment of a ceramic brick production plant – a tunnel, and/or chamber, and/or ring, and/or shaft furnace without special equipment;

21. eliminating contact of raw materials with the furnace lining to avoid destruction of the lining;

22. increasing the recovery time to reduce the final process temperature;

23. elimination of low service life between repairs and long manufacturing time of replacement parts of the matrix press.

The claimed technical solution complies with the patentability condition of “novelty” imposed on inventions, since when determining the level of technology, no technical solution was identified that has features identical (i.e., coinciding in the function they perform and the form of execution of these features) to the set of features listed in the invention formula, including the characteristic of the purpose.

The claimed technical solution complies with the patentability condition “inventive step” imposed on inventions, since no technical solutions have been identified that have features that coincide with the distinctive features of the claimed invention, and the influence of the distinctive features on the specified technical result has not been established.

The claimed technical solution meets the patentability requirement of “industrial applicability” imposed on inventions, since it can be manufactured using known materials, components, standard technical devices and equipment.

Claims (1)

A method for processing iron-containing raw materials, zinc-containing raw materials, iron-zinc-containing waste from metallurgical production, including zinc-containing sludge and dust, sludge and dust from converter production, sludge and dust from electric smelting production, blast furnace sludge and dust, oily scale, allowing for the production of direct reduction iron, dezincification of raw materials, deoiling of oily scale, isolation of zinc in the form of oxide and zinc salts, consisting in the fact that during the processing, waste and a solid reducing agent are stored, then the waste and solid reducing agent, binding and sintering agents are crushed to sizes less than 1 mm, the quantitative composition of the waste is analyzed to calculate the stoichiometric amount of the required pure carbon of the reducing agent used to reduce iron and zinc, depending on their content in the iron-zinc-containing sludge, then the ingredients are dosed, iron-zinc-containing sludge is introduced into the composition of the mixture being processed, oily scale, solid reducing agent from the series coal, coke, coke, coal fines and dust in terms of pure carbon not more than 110% of the stoichiometrically required for the reduction of iron and zinc; if the content of iron oxides in iron-zinc-containing sludge is more than 85%, alkaline sintering agents from the series oxides and carbonates of calcium and magnesium are added to the mixture in a stoichiometric ratio; then add a mineral binder required for cold briquette formation, from the series: cement, bentonite, lime, liquid glass, then mix the waste, reducing agent, sintering binder, binder for cold briquette formation, dose water to a mixture consistency that allows the briquette to be formed by extrusion or pressing, then form the briquettes, then stack the briquettes into piles, the dimensions of which allow it to be loaded into a tunnel, chamber, shaft or ring kiln, place the pile on a trolley and feed it into the briquette drying zone, then dry the briquettes in the pile with air or purified flue gases, while the drying process is carried out in a separate unit in the drying chamber, while the drying of the briquettes can be combined with the firing process in one apparatus, then fire the briquettes in the pile in the firing furnace, while the composition flue gases formed during fuel combustion are reducing in the main firing zone, whereby iron and zinc are reduced, and the reduced zinc evaporates from the briquettes at the firing temperature, passing into the gas phase, and is transferred by the flue gases to the flue gas post-oxidation zone, then the flue gases are further oxidized in order to oxidize CO and zinc to higher oxides, whereby in the flue gas post-oxidation unit and in the flue gas outlet zone from the firing chamber the flue gas composition must be oxidizing, for the post-oxidation of CO to _CO2 and zinc vapor to zinc oxide, post-oxidation is carried out by feeding an additional amount of air into this zone; The recovered zinc evaporates from the briquettes at the firing temperature into the gas phase and is transferred by the flue gases to the flue gas oxidation zone, where it is oxidized to zinc oxide, then the flue gases are cooled in recuperative heat exchangers, then the flue gases are cleaned of solid dust - zinc compounds, dust in the filter unit, then the briquettes are cooled in the stack.

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