RU2692390C1 - Method of metallurgical units lining and device for its implementation - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: group of inventions refers to metallurgy, namely to technologies of lining of metallurgical and other thermal units by shotcrete method and its hardware design. Method of lining metallurgical units involves depositing on their inner surfaces using a nozzle of a compressed air-saturated stream of a prepared composition based on a water-wetted refractory mixture, which is prepared by wetting the dry refractory mixture with water in a turbulent compressed air flow. Further, the stream of the composition is diluted and saturated with a curing agent in an additional stream of compressed air. Prior to application of prepared composition on internal surfaces of units its flow is compacted. Device for lining of metallurgical units includes nozzle with housing. Adapter of inlet for supply of dry refractory mixture and water supply branch pipe are arranged in the flow of compressed air to the inlet end of the case. Nozzle body comprises vacuum chamber equipped with nozzle for feeding mixture of hardener with compressed air. Outlet end of nozzle is convergent.

EFFECT: improved quality of preparation, uniformity and stability of composition of lining mixture, density, porosity and strength of which approximated by properties to filling refractory concrete, simplified design of lining device and reduced its dimensions, as well as reduced time for installation of lining.

9 cl, 4 dwg, 6 ex

Description

The group of inventions relates to the field of metallurgy, namely to the technology of lining of metallurgical and other thermal units by the method of gunning and its hardware design.

In the general case, the method of lining by gunning the surfaces of various units and the design of the device for its implementation are given in the reference literature [A brief polytechnical dictionary. - M .: State publishing house of technical and theoretical literature. (Editorial Council: Yu.A. Stepanov, F.S. Demyanyuk, A.A. Znamensky, and others.) 1956, p. 954, the term “gunning”]. The method involves applying a special cement mortar (for metallurgical units - refractory mixture) under the action of compressed air, carried out by means of a cement gun (device for lining). The dry mixture is loaded into a cement gun, from which it enters under pressure of air into a hose, ending with a nozzle tip. Before entering the nozzle the mixture is automatically wetted. The resulting shotcrete (pneumatic concrete) has great strength, density, water and airtightness.

The most complete level of technology in the field of flare gunning of refractory materials and its analysis are described in detail in the RF patent for the invention “Device for gunning of refractory material and nozzle for gunning” [Description of the invention to the RF patent №2363543 of January 22, 2004, IPC W05B 7/14 , ВВВ 13/00, publ. 08/10/2009 Bull. # 22]: Two widely used gunning methods for creating and repairing refractory linings are known: gunning by nozzles and gunning of dense concrete (density above 2.4 kg / cm ³ ) by a pump. Unlike other casting methods, these gunning methods do not require the creation of formwork for casting refractory linings and their use provides easy application of linings even on irregular shapes or in those cases where formwork is difficult to construct. Accordingly, gunning methods have become widely used in the creation and repair of refractory linings, especially in furnaces, such as blast furnaces, blast stoves, electric furnaces, casting ladles, troughs, oxygen converters, reheating furnaces, etc.

In the nozzle gunning method (the “dry” gunning method), the dry powdered material to be gunned is pneumatically fed through a transporting hose to the nozzle unit, where water is added to form a wet, very viscous guncrete mass with good adhesion properties. The gunning mass is ejected from the nozzle so that it adheres and hardens on the section of the furnace wall, thereby creating or restoring the refractory lining of the furnace.

The method of gunning with a nozzle does not require preliminary mixing of the material with water and, therefore, its use can quickly and within a short period of time after the notification, produce work, and minimal equipment cleaning is required. Also, its use does not require the mandatory use of the form for casting the lining, thereby reducing the cost of work and increasing labor efficiency, as well as the possibility of producing, for example, repairing both hot and cold linings of furnaces.

However, in the method of gunning with a nozzle, it is difficult to completely wet and thoroughly mix the material and the water jet when they are transported in a pipe or nozzle. This is especially true when using short, less than 1.5 m long shotcrete tubes. In these cases, the disadvantage related to the thoroughness of mixing results in less than optimal and desired homogeneity of the applied mass, less density and increased open porosity, as well as an increase in material waste due to rebound of aggregated particles and poor adhesion of the mass, and to excessive dripping of material from the pipe. The problem with the great dryness or poor wettability of the shotcrete material that is applied to the desired location is that some of the material does not adhere to the substrate, and this leads to the loss of deviated particles (known as “rebound”), which leads to a decrease in the proportion adhered to the wall of the unit applied material, thereby deteriorating the quality and durability of its refractory lining. The density of such a lining in practice does not exceed 1.8-2.3 kg / cm ³ .

These drawbacks are deprived of pump-masking methods (“wet” gunning methods), which create refractory linings with greater uniformity of properties and better physical properties than those obtained by the method of gunning with a nozzle, they are usually used to create monolithic structures of high density. When applying the method of gunning with a pump, the shotcrete mass is obtained by mixing the dry material with water in a separate mixer before being supplied to the gun concrete device. Dry powdered material is pre-mixed with water in a mixer and then pumped through a feed hose to a concrete device (pump), which throws the shotcrete mass onto the surface of the formation. Usually, a reagent is added to the gunned mass to improve the setting at the nozzle before the gunned material is applied to the surface of the furnace wall. This method is used for the application of dense refractory mixtures with high strength. This type of mixtures cannot be applied using dry shotcrete equipment.

The disadvantages of this method are that it is necessary to mix the dry material with water in a separate container before reaching the appropriate consistency. Thus, the material for the gunning method is mixed before it is supplied by the injection pump into the concrete device, which requires additional equipment, such as a mixer, and costly means for delivery and considerable labor costs, compared to the method of gunning by a nozzle. In addition, it is important to accurately control the amount of water supplied to the shotcrete material when using the pumping method to maintain the correct consistency. This requires a qualified operator in the application of the lining method of gunning pump to maintain the correct amount of water to obtain the desired composition. If too little water is used, it may set or prematurely harden the shotcrete material in the pump or supply hose. Conversely, if an excess amount of water is used, then the accumulation of solid particles and fine powder contained in the shotcrete material, which should be sprayed, can occur, with the formation of uneven and poor quality layers of refractory material.

An additional disadvantage of the method of shotcrete pump is the complexity of the interaction of the mixer and the pump. A certain amount of the shotcrete material remains in the supply hose and nozzle, which leads to waste material and an increase in the cost of labor for operating and cleaning the equipment. Also, the equipment for this method of shotcrete is cumbersome and requires a larger number of service personnel.

In addition, unlike the method of gunning by nozzles, which can be used to repair the furnace walls at temperatures above 1000 ° C, attempts to use the method of gunning with a pump to repair refractory linings at high temperatures were not considered successful.

To eliminate the above disadvantages, the corresponding devices were created - see the description of the invention to the patent of the Russian Federation No. 2363543.

One version of the device for gunning a refractory material comprises a nozzle with an internal channel having an inlet end into which the wetted material is introduced, and an outlet end from which the material is sprayed. The inner tubular element contains one through hole and a plurality of through grooves located around the circumference. The outer channel is located around the inner channel and communicates with it, and has an inlet end for introducing gas into it, which is passed through the outer channel and pushes the wetted material passing through the inner channel.

The device according to the second variant contains a hose for feeding the material, where water is supplied through a special inlet to wet the material. The inlet connects the hollow flange to the inlet end of the outer tubular member. The wetted material through the nozzle out, with the mixing chamber located in an intermediate position and communicated with the hose for feeding the material and contains an inlet for the introduction of the mixing gas.

Among the drawbacks of the listed options for devices, it should be noted that work exclusively with a “wet” composition, which was finally prepared for gunning, is formed only by a working jet for applying quality lining layers on the surface of various aggregates. As a result, the design of the nozzle is complicated and its dimensions increase, which makes it difficult to work in limited volumes and cramped conditions. In addition, when working with injection pumping equipment, all, to a lesser extent, characteristic disadvantages of this method of gunning remain — a certain amount of gunned material still remains in the supply hose and nozzle, which leads to waste material and increased labor costs for operation and cleaning equipment.

In addition, in a number of other technologies of gunning known method of vortex (flare) gunning of cylindrical lining and device for its implementation [Description of the invention to the patent of Russian Federation №2108397 from 28.08.1995, IPC S21S 5/44, F27D 1/16, publ. 04/10/1998]. The method includes feeding the lining of the gunning components of the gunning installed along the axis of the lining of the gunning tuyere, flowing from the gunning nozzle in the form of a swirling single vortex flow, adhesion of the supplied gunite mixture particles simultaneously on the entire cylindrical surface of the gunned lining section and forming a layer of gunstones on it simultaneously -covers, while the components of gunning to the lining are supplied from the end nozzle of the gunning tuyere, which has an outer round edge, and twist into a single vortex flow in a hollow cone with an external opening angle of at least 45 °, and the adhesion of the gunning mixture particles simultaneously over the entire cylindrical surface of the gunned lining site is ensured by creating the necessary values of the radial and tangential velocity components of the gunning mixture particles by adjusting the degree of twisting of the single vortex flow or its components in one direction or another.

A device for implementing this method contains a tank with a gunning mixture, fitted with each other, a pneumatic transport unit, pipelines for supplying components of gunning, associated with the corresponding gunning channels with a nozzle, a swirler of at least one gunning component fed through This gunning lance is made with an end nozzle having an outer circular edge, with the possibility of feeding from it to the lining of the components of gunning in the form of a swirling single vortex lumen output, provided with a mechanism for its vertical movement mounted on the mobile chassis, and a protective screen, and the swirler docked at least one channel gunning lance.

The disadvantages of the method include the large dimensions of the device for its implementation. In addition, the creation of a single swirling vortex flow is relevant and possible for implementation only with mixing of the components of shotcrete and ends at the stage of the mixture exit from the nozzle, where there are straight-line inertial forces. Large external angles of opening the flow of the shotcrete mixture make it possible to apply it on a high-quality cylindrical (horizontal) surface of a small diameter of the units under repair, however, in the vertical plane, large angles lead to traditional losses of the shotcrete mixture due to its rebound. As a result, the known method and device do not have the versatility of application for the lining of many metallurgical units and their elements, with the exception of those including spherical and cylindrical surfaces. It should also be borne in mind that the torch application of the gunning mixture is used primarily for the hot repair of metallurgical units and is rarely used in the manufacture of linings of newly built units, as well as large-volume linings.

Full automation of the process of applying the sprayed mixture to the unheated, unprepared surface of the unit (the so-called "hot" repair) often leads to an unpredictable result.

The problem to be solved by the group of claimed inventions and the technical result achieved is to create a new method of lining metallurgical and other thermal units and its constructive implementation, which allows to improve the quality of preparation, uniformity and stability of the composition of the lining mixture, such properties as density, porosity and strength approaching bulk refractory concrete with a density above 2.4 kg / cm ³ while simplifying the design of the device for lining and reducing its dimensions. In addition, significantly, the installation time of the lining is reduced to 1.5-2.0 times.

To solve the problem and achieve the stated technical result in the method of lining metallurgical units, including applying to their internal surfaces using a nozzle of a stream saturated with compressed air of the prepared composition based on a refractory mixture moistened with water, the composition is prepared by wetting the dry refractory mixture with water in a turbulent flow compressed air, after which the composition stream is discharged and saturated with hardener in an additional compressed air flow, and before bearing of the prepared composition to the internal surface of its flow compacted aggregates.

Besides:

- saturation of the air flow of the refractory mixture with water and its subsequent saturation with a hardener are carried out uniformly over the cross section of the flow;

- the flow of the prepared composition is applied to the inner surfaces of the metallurgical aggregates at a distance of 0.2-4.0 m and at an angle to the normal, not exceeding 60 °;

- the prepared composition is applied to the internal surfaces of the metallurgical aggregates sequentially in several layers, while the composition has the same or different chemical composition for each layer.

Also, to solve the task and achieve the stated technical result in the device for lining metallurgical units, including a nozzle with a body, to the inlet end of which is suitable a supply pipe in the compressed air dry refractory mixture and a water supply connection, while the nozzle body contains a vacuum chamber, equipped with a pipe for supplying a mixture of hardener with compressed air, and the outlet end of the nozzle is made tapering.

Besides:

- the supply pipe in the compressed air flow of the dry refractory mixture is installed coaxially with the nozzle body;

- the water inlet pipe to the nozzle body includes a perpendicularly placed collector with a number of holes evenly distributed around the body perimeter;

- a pipe for supplying a mixture of hardener with compressed air to the discharge chamber of the nozzle body includes a perpendicularly placed collector with a number of holes uniformly distributed around the perimeter of the body;

- the pipe for supplying the mixture of hardener with compressed air includes a channel for supplying compressed air, perpendicular to which there is a channel for supplying the hardener.

The group of inventions is illustrated by drawings, where:

- in fig. 1 shows a general view of the most significant fragment of the construction of a device for lining metallurgical and other thermal units — a nozzle with a housing — in an axonometric projection;

- in fig. 2 is a longitudinal sectional view of the liner of FIG. one;

- in fig. 3 shows section A-A of FIG. 2 - collector design for the supply and uniform distribution of water into the flow of a dry mixture saturated with compressed air on the basis of a refractory composition;

- in fig. 4 - section BB of FIG. 2 - a collector design for supplying a mixture of a hardener with compressed air to a stream of a wetted refractory composition.

A device for lining metallurgical units includes a traditional, fairly common (commercially available) set of equipment, which includes, for example, most of the equipment of a typical installation for dry gunning (conventionally not shown), whose function is to feed into the transport pipeline (line) 1 under the action compressed air dry refractory mixture, and further - the nozzle 2 with the housing 3, to the inlet end 4 which coaxially suited to it the pipe 5 supply in the compressed air flow dry refractory mixture and a pipe 6 for supplying water, wherein the nozzle body 3 comprises a vacuum chamber 7 equipped with a pipe 8 for supplying a mixture of hardener with compressed air, and the outlet end 9 of the nozzle 2 is tapered. Since the outlet end 9 is made as a separate part from special wear-resistant materials, such as polyamide, it is called “nozzles”.

The pipe 6 for supplying water to the body 3 of the nozzle 2 includes a perpendicularly placed collector 10 with a series of holes 11 uniformly distributed around the perimeter of the body 3.

The pipe 8 supplying a mixture of hardener with compressed air to the chamber 7 discharging the housing 3 of the nozzle 2 includes a perpendicularly placed collector 12 with a number of holes 13 uniformly distributed around the body perimeter. The pipe 8 supplying the mixture of hardener with compressed air is made in the form of a channel 14 of compressed air, which is perpendicular to the channel 15 for supplying hardener.

The method implemented by the present device for lining metallurgical aggregates involves applying to the inner surfaces through the outlet end 9 of the nozzle 2 a stream of compressed air saturated with compressed air based on a refractory mixture moistened with water, while the composition is prepared by wetting the dry refractory mixture with water in a turbulent stream of compressed air, after which the composition stream is discharged and saturated with hardener in an additional stream of compressed air, and before applying the prepared composition to the morning surfaces of the aggregates are compacted by narrowing the cross section of the outlet end 9 of the nozzle 2.

Saturation of the air flow of the refractory mixture with water and its subsequent saturation with a hardener is carried out uniformly over the flow section, while the flow of the prepared composition is applied to the inner surfaces of the metallurgical units at a distance of 0.2-4.0 m and at an angle to the normal not exceeding 60 °, successively in several layers, while the composition has the same or different chemical composition for each layer, which is determined by the technological requirements for the qualitative composition of the lining.

Let us analyze the essential features of the group of inventions.

Wetting a dry refractory mixture with water in a turbulent stream of compressed air is known from the "dry" method of gunning. However, in the inventive method, the flow of the mixture obtained is not applied to the surfaces of the metallurgical units, but is discharged in a conditionally closed volume (chamber 7) of the housing 3, which results in a more complete and uniform wetting of the dry refractory mixture. Something similar, but more pronounced dilution of the moistened mixture can be observed with the "dry" method of gunning at the nozzle exit, only this process is associated with a nonnormable redistribution of the amount of water over the cross section of the wetted flow, resulting, in particular, the local fluidity not provided by the lining technology fragments. After discharging in a closed volume of the housing 3 wetted with a stream of refractory mixture saturated with air, a hardener is introduced into it in the form of an independent stream of mixture saturated with air bubbles. Unlike the final stage of the “wet” shotcrete method - saturation of a dense airless flow of a moist refractory mixture with air bubbles, - a turbulent flow of a dry refractory mixture moistened with water does not require additional preparation, and its natural saturation with a hardener occurs. After that, a composition of the required chemical composition and physical properties is obtained, ready for application on the surface of metallurgical aggregates. Next, the flow of the prepared composition is compressed by pushing it towards the tapering outlet end 9 of the nozzle 2. As a result, the flow rate increases and at the exit of the nozzle 2 a compact jet of a saturated air bubble filled with a uniform mixture of refractory mixture, water and a hardener is formed. The discharge of the flow at the outlet seals the working composition, freeing it from the now unnecessary air bubbles. On the surface of the unit lies a layer of composition similar in properties to the bulk concrete.

Obtaining such a result becomes possible as a result of successive saturation of the air flow of the refractory mixture with water and its subsequent saturation with a hardener evenly over the cross section of the flow, which is facilitated by its forced turbulence.

The flow of the prepared composition is recommended to be applied to the inner surfaces of metallurgical aggregates at a distance of 0.2–4.0 m and at an angle to the normal, not exceeding 60 °. Distances shorter than 0.2 meters do not fully ensure the removal of air bubbles, the lining is more porous, which reduces its performance. A distance of more than 4.0 meters contributes to the formation during the flight of particles of a composition of unreasonably large conglomerates, which create irregularities on the surface of the aggregate — unnecessary protrusions (ripples) and, as a result, influxes and drips that require subsequent stripping and / or calibration. This also contributes to the application to the internal surfaces of metallurgical aggregates of the stream of the prepared composition at an angle to the normal exceeding 60 °. Significantly larger 60 ° angles of attack contribute to the rebound of a part of the composition and its transfer to waste.

The prepared composition is applied to the inner surfaces of metallurgical aggregates in one layer or successively in several layers, while the composition has the same or different chemical composition for each layer. Obviously, depending on the type of metallurgical equipment - blast furnaces, blast furnace heaters, electric furnaces, casting ladles, casting troughs, oxygen converters, reheating furnaces, etc., lay the thickness of the lining, the number of layers for its formation and design the composition including for each layer. For example, in a blast furnace, the outer layer of the lining should have greater wear resistance compared to the inner layers, which is ensured by the appropriate composition of the refractory mixture being applied.

As a result, the claimed lining method provides the ability to work with a wide range of geometrical dimensions of metallurgical aggregates, similar to the “dry” gunning method, but with the quality of the lining that is inherent in the “wet” method and, as can be seen from the above information, with significantly lower implementation costs and simpler design.

A typical device for lining metallurgical units includes a nozzle 2 with a housing 3, to the inlet end 4 of which is suitable a pipe 5 for supplying a dry refractory mixture in a stream of compressed air and a pipe 6 for supplying water. However, in the claimed device, the body 3 of the nozzle 2 contains a vacuum chamber 7 (i.e., a guaranteed cavity, the length of which conditionally reaches the outlet of the openings 13 of the collector 12 to the inside of the body 3), which contributes to additional turbulence in the flow of moistened refractory mixture and creates favorable conditions for its additional mixing and saturation with hardener. After the holes 13, the flows are summed up, and the turbulence mode weakens and is maintained due to the forced mixing of the mixtures through a plurality of holes 13 that are evenly distributed around the circumference, similar to the water supply through the holes 11 of the collector 10.

It should be noted that the hardener is introduced into the flow of moistened mixture in the form of a pre-prepared air mixture. This is served by the corresponding pipe 8 on the housing 3, which includes a channel 14 for compressed air supply, which is perpendicular to the channel 15 for supplying the hardener. Preliminary preparation of an air mixture with, predominantly, a liquid hardener is ensured by the fact that a stream of hardener is brought perpendicularly or close to this to the air flow, and due to, inter alia, the ejection mode, they are pre-mixed. The thoroughly mixed air mixture of the refractory mixture, water and hardener continues along the body 3 to the nozzle 2, the discharge end 9 of which is made tapering. The narrowing of the nozzle 2 smoothly compresses the flow of the prepared composition and increases its speed, which at the exit is drawn up into a compact working jet. Thus, a fairly simple constructive means is provided for the implementation of the claimed method.

Additional structural solutions of the device for lining metallurgical aggregates enhance the effect obtained. These solutions include the technological coaxial arrangement of the nozzle 5 for supplying a dry refractory mixture to the casing 3 of the nozzle 2 in the compressed air flow and the presence on the casing 3 and in its discharge chamber 7, preferably two perpendicularly placed collectors 10 and 12, one of which is water inlet nozzle 6 and the other with an air supply nozzle 8 nozzle 8 for supplying a mixture of hardener with compressed air. Both manifolds 10 and 12 are provided with rows of holes 11 and 13 uniformly distributed around the perimeter of the casing. These design features contribute to obtaining a working composition at a much shorter length of the casing 3 of the nozzle 2, unlike the brushless design. This also contributes to the implementation of the nozzle 8 for supplying a mixture of hardener with compressed air in the form of a channel 14 for compressed air supply, which is perpendicular to the channel 15 for supplying a hardener, although this is not necessary. However, the best effect and maximum versatility of equipment can be obtained by using all the design features of the device.

Of course, setting up such a device requires the special knowledge and practical experience typical of setting up well-known commercially produced equipment for gunning.

It should be noted that the result of the implementation of the group of inventions is the creation of a new class of special equipment - shotgun-installations for shotgun-creting. The etymology of the term comes from the English. "Gunning" - "dry" gunning and eng. "Shot" - shotcrete ("wet" gunning). The result is “Shotgun (shotgun)”, a technology and installation consisting mainly of elements of equipment for “dry” shotcrete with properties and the resulting effect of equipment for “wet” shotcreting.

The implementation of a group of inventions can be illustrated by the following examples:

Example 1. Creating an original device for lining metallurgical units.

It should be noted that for the manufacture of the device, you can use elements of standard lining equipment, mainly for "dry" gunning. Thus, the shotgun installation includes, for example, a piece of equipment of a standard gunning machine (conventionally not shown) with a receiving hopper for a dry refractory mixture, a revolving rotor equipped with a plurality of batch chambers, a unit for their unloading with supply air for unloading, an exhaust chamber equipped air supply for transportation and the main pipeline. Additionally, a compressor is mounted (in case of a lack of transport pneumatic supply) and a container for curing additive is hung.

The transport pipeline (line) 1 ends with a nozzle 5 for supplying a dry refractory mixture in the compressed air flow. This pipe 5 is connected to the housing 3 of the nozzle 2 through its inlet end 4.

In addition, the shotgun installation is equipped with a set of feed pipes and hoses for the refractory mixture, curing additive, air and water.

To the main pipeline connect the working body, made according to the invention and including, in particular, the nozzle 2 with the housing 3, to the inlet end 4 of which fits the pipe 5 supply in the compressed air dry refractory mixture and the pipe 6 water supply, while the body 3 of the nozzle 2 contains a discharge chamber 7, equipped with a nozzle 8 for supplying a mixture of hardener with compressed air, and the outlet end 9 of the nozzle 2 is made tapering.

To achieve the maximum technical result, the nozzle 2 with the housing 3 is equipped with all or part of the essential structural features:

- the pipe 5 for supplying a dry refractory mixture in the compressed air flow is set coaxially with the body 3 of the nozzle 2;

- pipe 6 supplying water to the body 3 of the nozzle 2 includes a perpendicularly placed collector 10 with a number of evenly distributed along the perimeter (section perpendicular to the longitudinal axis) of the body 3 of the holes 11, the axes of which, for example, are inclined to the axis of the body 3 of the nozzles 2 and away from it (although it is not necessary);

- pipe 8 supplying a mixture of hardener with compressed air to the chamber 7 discharging the housing 3 of the nozzle 2 includes a perpendicularly placed collector 12 with a number of holes 13 uniformly distributed around the perimeter of the housing 3, the axes of which are also, for example, inclined to the axis of the housing 3 of the nozzles 2 and to the side from him (although this is also not necessary);

- nozzle 8 for supplying a mixture of hardener with compressed air is made in the form of a channel 14 for compressed air supply, perpendicular to which a channel 15 for supplying a hardener is located, which allows for the mode of its ejection, and, therefore, to obtain a better-quality fine mixture of hardener with air.

The assembled shotgun installation is additionally equipped with a control system, tested, labeled accordingly and delivered to the consumer in this form.

The installation works as follows.

Through the receiving bunker (hereinafter, the work of typical technological conversions is not conventionally illustrated) the gunning mixture enters the chambers of the revolving rotor. Due to the rotation of the rotor, the chamber with the material enters the unloading point. With the help of compressed air, the chamber is unloaded with the material. Through the outlet chamber, the mixture enters the initial part of the line and then with the help of compressed air, i.e. in the air flow (so-called pneumatic supply) the mixture is transported at high speed to its final section - to the nozzle 5 for supplying a dry refractory mixture to the body 3 of the nozzle 2.

Through the collector 10 of the nozzle 6, the refractory mixture is moistened with water and in this form enters the discharge chamber 7 on the housing 3, where the wetted mixture is mixed with the hardener through the collector 12 of the nozzle 8. Next, the prepared composition is compacted due to the narrowing of the nozzle 2 and is pulled out to the outside - towards the lined surface of the metallurgical unit.

The composition is applied to the lined surface in one or several layers.

Example 2. Refinement of a commercially available unit for "dry" gunning.

A certain enterprise or its specialized service, professionally engaged in the lining of metallurgical units, has a working gunning machine, for example, the AC1-AC6 series, the SSB series (SSB 02, 05, 14 and 24), MPCS 4 or other installations.

To expand the technological capabilities of the machine, it was decided to modernize it and bring it to the level of specialized shotgun installations.

Modernization is reduced to dismantling its own working body (nozzle) and equipping the machine with a working body made according to Example 1. If necessary, appropriate changes are made to the control system of the installation.

Example 3. The lining of the blast furnace under construction.

A furnace casing was built on the working site, on the inner surface of which tubular heat exchangers were mounted, a forge and a shoulder were erected. The latter are covered with technological flooring. There is an eyeliner for energy resources - an electrical network of 380 V; 0.64 MPa compressed air network and a water supply system. The working pressure in the gunning unit, depending on the machine design, the distance from the gunning unit to the gunned surface and the length of the material hoses, should be in the range of 0.2 to 0.6 MPa. The pressure in the water tank should be 0.05-0.1 MPa more than the working pressure in the gunning installation. During gunning, the air pressure in the shotcrete unit and the water pressure in the water tank should be constant.

It is necessary to make the lining of the steam, the shaft and the top of the blast furnace. To do this, develop and make technological regulations of work performed.

Available materials for shotgun-crete are a fire-resistant dry mixture, for example, based on silicon carbide (for the lining of the first layer) and an aluminosilicate composition (for the lining of subsequent layers); drinking water quality and curing additive, for example, based on liquid glass.

Inside the furnace casing they deliver the installation for shotgun-kretirovaniya, which is placed on the technological flooring, connected to the power grid and filled with the appropriate materials for the lining of the first layer. The installation is started and, using a special stand, they are brought to a predetermined mode of operation.

In accordance with the regulations, the installation operator begins the process of applying the first layer of the prepared lining composition using the nozzle 2 on the inner surface of the furnace casing. In one or several passes, the first layer of lining is applied on the perimeter of the inner surface of the casing to the height of the operator’s growth (so-called lining spacing), which also bricks the tubular heat exchangers. After raising the flooring to the next step, the lining process is repeated and so on the entire height of the casing.

At the end of the application of the first layer of lining the flooring is lowered to the level of the shoulders. The equipment is washed and filled with materials for lining the next layer. The installation is restarted and, using a special test bench, is brought to the specified mode of operation.

Also, in accordance with the technological regulations, the installation operator begins the application process using the same nozzle 2 on the first, dried naturally or forcibly, layer of the lining of the next layer of the prepared lining composition. In one or several passes, another lining layer is applied along the perimeter of the inner surface of the lined with the first layer of the jacket, which has, for example, different operational properties as compared to the properties of the first layer, for example, more durable, dense, heat-resistant, etc. and corresponding thickness. After lifting the flooring to the next step, the lining process continues. If necessary, in accordance with the regulations, the refractory mixture is changed to a mixture with other operational properties - special, for example, for steam, mine, and furnace top.

After applying the lining on the walls of the metallurgical unit, it is kept until it is completely dry, the formed surface is cleaned (calibrated) and, if necessary, polished.

This technology makes it possible to reduce the installation time of the lining by 1.5-2.0 times compared to the “wet” method of shotcrete. As a result, construction costs have been significantly reduced.

After completion of the work, the device is washed, purged with air and left as such for later use.

Example 4. Recovery installation of the refractory lining of the main gutter and blast furnace transport chute system (intermediate repair).

Make a technological map of the upcoming repairs.

The installation of the lining begins with the preparation of the surface on which the concrete will be applied. The surface must be cleared of residues of smelting products (slag, cast iron), oxidized concrete must also be removed. All "unbound", poorly adhered concrete must also be dismantled.

The required amount of refractory material has been prepared at the work site.

The equipment is connected to energy carriers (air, water, electricity) and tested in idle mode (no load).

With the help of compressed air they blow the working surface from dust and small third-party garbage.

Depending on the area of work, refractory materials of various density and various purposes can be used (from installation of insulation materials to dense working materials with a density above 2.4 kg / cm ³ containing Al ₂ O ₃ , SiC base material).

According to the technical specification, the operator, using the device for lining, namely the nozzle 2 with the body 3, proceeds to work on applying (restoring) the refractory lining to the geometric dimensions described in the technical specification.

This technology allows at one time to apply concrete with a thickness of more than 100 mm, since this technology uses a binder material. During dry gunning, concrete of such thickness must be applied in layers, which creates a certain, undesirable lamination of the lining.

At present, the main method of restoring the working lining of the main gutter is exclusively the method of dry gunning.

When using the technology of installation of refractory lining by the method of shotgun-kretirovaniya - "SHOTGAN" (or "SHOTGUN"), - the resistance (throughput of the main groove) is increased by 25-30%.

Example 5. Lining of a blast furnace during its overhaul.

There is a need for scheduled repair of a blast furnace, the lining of which is lined with refractory bricks, partially worn out from time to time, and the resource of which has not yet been worked out.

The stove is stopped and its internal surface is blown out to reduce the temperature to the level of provision of conditions for repairs, including the removal of poisonous gases. The shoulders and horn with the remnants of liquid metal and slag are covered with insulating flooring.

The inner surface of the blast furnace is prepared for repair - remove potentially dangerous areas of the brickwork and smooth out. Pick up the composition of materials for lining. Make a technological map of the upcoming repairs.

The installation for shotgun-cracking is delivered, it is connected to the power supply systems, the materials for the upcoming lining are delivered and the installation is filled with them, which is started and using a special stand is brought to the specified mode of operation.

In accordance with the technological map of repair work, the installation operator begins the process of applying with the help of a nozzle 2 on the inner surface of the furnace or on its individual sections of the refractory composition, which is firmly seized with the brickwork or with its previous layer. So continue until the specified thickness of the lining is restored. Due to the heated walls, the process of drying the composition is accelerated.

After the restoration of the lining of the furnace, its internal surface, if necessary, cleaned (calibrated). Next, the inner space of the furnace is freed from imported equipment and materials. Remove thermal insulation flooring. Next, perform routine maintenance to start the blast furnace, in particular, the lining is dried and heated to 700-800 ° C.

After completion of the work, the device for lining is washed, blown with air and, in this form, is left for later use.

Thanks to the use of shotgun-cratering technology, the repair process of the blast furnace was significantly accelerated, and the costs of its implementation were reduced.

Example 6. The lining of a small metallurgical unit - a typical 50-ton casting ladle.

A feature of the lining of the inner surface of such a bucket is extremely constrained conditions for work - this is a conventional cone with a height of 2800 mm and diameters of 2620 mm and 2340 mm.

As is known, fireclay bricks, as well as rammed or refractory masses are widely used for lining newly built or repaired steel casting ladles. Their installation is quite time-consuming and lengthy process. The lining durability of steel-teeming ladles is, as a rule, 7-15 heats.

As is known, intermediate repairs of the lining by gunning allow to increase its durability by 30-50%.

The problem of high-quality and sufficiently fast lining of the above-mentioned steel casting ladle is solved by using an appropriate lining device made according to the invention. In contrast to the equipment for “wet” gunning, the dimensions of the working body of this device - nozzle 2 with body 3 and nozzle 5 for supplying dry refractory mixture, is about 1 m. With corrections for the length of the jet of the prepared refractory composition and bending radius of the supply hoses, about 1 is required 5 m of free space. The main working equipment is located outside the bucket.

For the lining of the internal space of the new steel-teeming ladle, all actions are performed according to Example 3 with forces, for example, of one operator.

In order to restore the lining of the steel-teeming ladle, during scheduled maintenance, actions are performed according to Example 5, adjusted for much smaller dimensions of the ladle and the absence of a bath with molten metal and slag — also by the forces of one operator.

After completion of the work, the device for lining is washed, blown with air and, in this form, is left for later use.

The newly lined or repaired steel teeming ladle is dried, heated to 700-800 ° C and transferred to work.

The durability of the mounted lining of a steel-teeming ladle made according to the technology of shotgun-cratering before intermediate repair is comparable to the service life of the lining, including its refurbishment, carried out according to the traditional technology - at least 20 heats. Intermediate repair using the technology of shotgun-kretirovania allows you to raise the resistance of the bucket up to 30 heats or more.

The above Examples 1-6 do not exhaust the possibilities of implementing the claimed group of inventions. Other ways of implementation are possible, the feature of which will be the use of essential features of inventions in various combinations and on various metallurgical and thermal units.

As a result of the solution of the task, a new method of lining metallurgical and other thermal units and a device for its implementation have been created, resulting in improved preparation quality, uniformity and stability of the composition of the lining mixture, the density, porosity and strength of which approached bulk refractory concrete with a density higher than 2 , 4 kg / cm ³ , simplified design of the device for lining and decreased its dimensions. In addition, significantly, the installation time of the lining was reduced to 1.5-2.0 times.

Claims (9)

1. A method of lining metallurgical aggregates, including applying a compressed air-saturated stream on their inner surfaces using a prepared composition based on a refractory mixture moistened with water, characterized in that the composition is prepared by wetting a dry refractory mixture with water in a turbulent stream of compressed air, after which the stream the compositions are diluted and saturated with hardener in an additional stream of compressed air, and before applying the prepared composition to the internal surfaces of the unit her stream is compacted. 2. The method according to p. 1, characterized in that the saturation of the air flow of the refractory mixture with water and its subsequent saturation with a hardener is carried out uniformly over the cross section of the stream. 3. The method according to p. 1, characterized in that the flow of the prepared composition is applied to the inner surfaces of the metallurgical units at a distance of 0.2-4.0 m and at an angle to the normal, not exceeding 60 °. 4. The method according to p. 1, characterized in that the prepared composition is applied to the inner surfaces of the metallurgical units in succession in several layers, while the composition has the same or different chemical composition for each layer. 5. Device for lining metallurgical units, including a nozzle with a housing, to the inlet end of which is suitable a supply nozzle in the compressed air flow of a dry refractory mixture and a water supply nozzle, characterized in that the nozzle body contains a vacuum chamber equipped with a nozzle for supplying a mixture of hardener with compressed air , while the outlet end of the nozzle is made tapering. 6. The device according to claim 5, characterized in that the supply pipe in the compressed air flow of the dry refractory mixture is installed coaxially with the nozzle body. 7. The device according to claim 5, characterized in that the water inlet pipe to the nozzle body includes a perpendicularly arranged collector with a number of holes uniformly distributed around the body perimeter. 8. The device according to p. 5, characterized in that the pipe for supplying a mixture of hardener with compressed air to the vacuum chamber of the nozzle body includes a perpendicularly placed collector with a number of holes evenly distributed around the perimeter of the body. 9. The device according to p. 5, characterized in that the pipe for supplying the mixture of hardener with compressed air is made in the form of a channel for supplying compressed air, perpendicular to which is a channel for supplying the hardener.

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