CN118406874B - Recycling method for cooperatively disposing lead-containing waste residues through steel dust and mud - Google Patents

Abstract

The invention discloses a resource utilization method for the coordinated treatment of lead-containing waste slag with steel dust, including: washing, desalting, dehydrating and drying the steel dust to obtain dechlorinated dust; batching, mixing and block-making the dechlorinated dust, lead-containing waste slag, waste glass and high-iron materials to obtain mixed bricks; sending the mixed bricks, reducing agent and returned slag to a roasting device, evenly distributing the materials, roasting in a reducing atmosphere, and obtaining crude lead, water-quenched slag and low-grade matte after smelting. The invention can avoid the pollution problem caused by the large-scale storage of steel dust and lead-containing waste slag, and realize the harmless treatment of smelting waste slag; and can utilize the complementarity between steel dust and lead-containing waste slag to simultaneously realize the resource treatment of steel dust and lead-containing waste slag, with a short process flow, wide adaptability of raw materials, and greatly reducing the disposal cost of lead-containing waste slag, achieving the dual goals of economic benefits and environmental protection.

Description

A resource utilization method for co-disposing lead-containing waste slag by steel dust and mud

Technical Field

The invention relates to the field of solid waste resource utilization and nonferrous metallurgy technology, and in particular to a resource utilization method for co-disposing lead-containing waste slag with steel dust and mud.

Background Art

Copper, lead and zinc smelting enterprises will produce lead-containing waste slag during the smelting process, such as smoke and smelting slag produced by pyrometallurgical enterprises, leaching slag, replacement slag, lead-silver slag, lead mud, etc. produced by hydrometallurgical enterprises. The composition and physical phase of different smelting waste slags vary greatly, and they also contain a variety of valuable metals such as Cu, Sn, Bi, Au, Ag, etc.; due to the toxicity and harmfulness of the rich non-ferrous metals themselves, these waste slags are mostly hazardous wastes. The current lead smelting process can only process a single type of material. It is difficult to centrally process all types of lead-containing waste slags in the same furnace. At the same time, the lead content in these lead-containing waste slags is generally less than 15%. The comprehensive utilization of these lead-containing waste slags with low lead content has always been a problem.

The flue gas pollutants and environmental dust powder generated during the production process of steel enterprises are collectively referred to as steel dust sludge. In addition to iron and carbon, steel dust sludge also contains valuable metal elements such as lead, zinc, and silver, and is a valuable secondary resource. Currently, only a small amount of steel dust sludge is returned to sintering for internal circulation within steel enterprises. Most of the steel dust sludge can only be accumulated in the factory due to the high mass fraction of potassium, sodium, chlorine, and zinc, which not only causes waste of resources, but also damages the surrounding ecological environment.

Based on the above situation, lead-containing waste slag and steel dust mud are both difficult to dispose of solid wastes in their respective industries. Is there a way to synergistically dispose of the two solid wastes, while recovering the valuable elements in the two solid wastes without increasing additional disposal costs, and realizing the synergistic resource utilization of the two types of solid wastes? This is the core problem that the present invention needs to solve.

Summary of the invention

In view of the deficiencies in the prior art, the present invention provides a resource utilization method for the coordinated disposal of steel dust and lead-containing waste slag, which can avoid the pollution problem caused by the large-scale storage of steel dust and lead-containing waste slag and realize the harmless treatment of smelting waste slag; it can also utilize the complementarity between steel dust and lead-containing waste slag to simultaneously realize the resource treatment of steel dust and lead-containing waste slag, with a short process flow and a wide adaptability of raw materials, which greatly reduces the disposal cost of lead-containing waste slag and achieves the dual goals of economic benefits and environmental protection.

The invention discloses a resource utilization method for co-disposing lead-containing waste slag with steel dust and mud, comprising:

The steel dust sludge is subjected to water washing, desalting, dehydration and drying to obtain dechlorinated dust sludge;

The dechlorinated dust sludge, lead-containing waste slag, waste glass and high-iron materials are batched, mixed and block-formed to obtain mixed brick materials;

The mixed brick material, reducing agent and returned slag are sent to the roasting equipment, evenly distributed and roasted in a reducing atmosphere. After smelting, crude lead, water-quenched slag and low-grade matte are obtained respectively.

As a further improvement of the present invention, the water content of the dechlorinated dust sludge is lower than 10%, the carbon grade is not lower than 10%, and the iron grade is not lower than 55%.

As a further improvement of the present invention, before batching, the raw materials with large particle sizes are crushed so that the particle size of each raw material is not greater than 5 mm.

As a further improvement of the present invention, the waste glass is discarded lead-containing glass, and the proportion of lead-containing glass is 5-10wt%.

As a further improvement of the present invention, the high-iron material includes at least one of pyrite slag, iron-rich slag from hydrometallurgy, iron powder, and iron-rich tailings, and the iron grade of the high-iron material is not less than 55%, and the sulfur grade is not higher than 8%.

As a further improvement of the present invention, the ratio of the dechlorinated dust sludge and the high-iron material is 20-40wt%, and the proportion of the dechlorinated dust sludge in the dechlorinated dust sludge and the high-iron material is not more than 80%.

As a further improvement of the present invention, the lead grade in the mixture after the dechlorinated dust sludge, lead-containing waste slag, waste glass and high-iron material are mixed is 10-20%, the copper grade is less than 10%, and the sulfur grade is not higher than 10%.

As a further improvement of the present invention, the calcination temperature is 1200-1400°C.

As a further improvement of the present invention, the flue gas generated during the roasting process is dusted, the collected self-produced ash is used for batching, and the flue gas after dust collection is desulfurized and then discharged in compliance with the emission standards.

As a further improvement of the present invention, the obtained crude lead, water-quenched slag and low-grade matte are reprocessed or sold.

Compared with the prior art, the present invention has the following beneficial effects:

The present invention performs synergistic treatment on steel dust and lead-containing waste slag. Impurities such as Fe, Si, Ca, and Al in the steel dust can be used as flux or slag-making agent for smelting the lead-containing waste slag. Carbon is used as fuel and reducing agent to participate in the reduction reaction of materials in the furnace. The raw materials have high synergy, and the purpose of treating waste with waste is achieved.

The raw material cost of the present invention is low, and the use of steel dust sludge to replace part of the additives and reducing agents can greatly reduce the disposal cost of lead-containing waste slag, with significant economic benefits;

The crude lead, low-grade matte and water-quenched slag produced by the present invention can all be used as products, no additional solid waste is generated, and complete comprehensive utilization of solid waste is achieved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a flow chart of the resource utilization method for the coordinated disposal of lead-containing waste slag by steel dust and mud disclosed in the present invention.

DETAILED DESCRIPTION

In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

The present invention is further described in detail below in conjunction with the accompanying drawings:

As shown in FIG1 , the present invention provides a resource utilization method for co-disposing lead-containing waste slag with steel dust and mud, comprising:

Step 1, washing and desalting the steel dust mud, so that the chloride ion content of the pretreated steel dust mud is ≤1.5%; dehydrating and drying the washed steel dust mud, so that the water content of the pretreated steel dust mud is less than 10%, so as to obtain dechlorinated dust mud; wherein the carbon grade of the dechlorinated dust mud is not less than 10%, and the iron grade is not less than 55%;

Step 2: batching, mixing and block-making the dechlorinated dust sludge, lead-containing waste slag, waste glass and high-iron materials to obtain mixed brick materials; wherein:

Before batching, the raw materials with large particle size (at least one of dechlorinated dust sludge, lead-containing waste slag, waste glass, and high-iron materials) are crushed to make the particle size of each raw material no larger than 5mm;

The waste glass is the commonly used waste glass, and preferably waste leaded glass is used, with the proportion of 5-10wt%;

The proportion of lead-containing waste slag is 50~75wt%;

The high-iron material includes at least one of pyrite slag, iron-rich slag of hydrometallurgy, iron powder, and iron-rich tailings. The iron grade of the high-iron material is not less than 55%, and the sulfur grade is not higher than 8%; wherein, the proportion of dechlorinated dust sludge and high-iron material is 20-40wt%, and the proportion of dechlorinated dust sludge in the dechlorinated dust sludge and high-iron material is not more than 80%, that is, the proportion of dechlorinated dust sludge replacing high-iron material is 0-80%, preferably, the proportion of dechlorinated dust sludge is 10-20wt%, and the proportion of high-iron material is 10-20wt%, and the mass ratio of dechlorinated dust sludge to high-iron material is more preferably 1:1;

The lead grade of the mixture after mixing dechlorinated dust mud, lead-containing waste slag, waste glass and high-iron materials is 10-20%, the copper grade is less than 10%, the sulfur grade is not higher than 10%, and the preferred sulfur grade is not higher than 8%.

After the raw materials are mixed evenly, the mixture is sent to a fully automatic hydraulic brick-making machine to form mixed bricks for stand-alone use; during the brick-making process, the materials are pre-watered to maintain appropriate humidity and directly pressed into shape (such as controlling the moisture content to 12-20%, preferably 15%), without adding other binders.

Step 3: Send the mixed brick material, reducing agent and returned slag to the roasting equipment, evenly distribute the materials, and roast them in a reducing atmosphere at a roasting temperature of 1200-1400°C. After smelting, crude lead, water-quenched slag and low-grade matte are obtained respectively. The crude lead, water-quenched slag and low-grade matte are reprocessed or sold. The flue gas generated during the roasting process is dusted, and the collected self-produced ash is used for batching. The flue gas after dust collection is desulfurized and then meets the emission standards; wherein,

Self-produced soot is mixed with dechlorinated dust sludge, lead-containing waste residue, waste glass, and high-iron materials to achieve zero discharge of solid waste;

The processing amount of reducing agent and returned slag is controlled according to the actual roasting demand. The reducing agent can be a commonly used reducing agent, such as coke. In addition, because steel dust contains carbon, the amount of coke (reducing agent) added can be appropriately reduced. For example, during the roasting process, the addition ratio of coke (reducing agent) can be reduced from 20% to 17%. Coke can also be added to the mixture to participate in brick making.

Example

A resource utilization method for co-disposing lead-containing waste slag with steel dust and mud, comprising:

S1. Raw material preparation: pre-treated steel dust (dechlorinated dust after washing), lead-containing waste slag, waste glass, iron powder, coke. The waste materials need to be crushed before mixing, and the materials should be ground to a sufficient particle size, preferably below 5mm. If the particle size is too large after screening, it needs to be crushed and ground again.

Taking the smelting white smoke produced by a copper smelter as raw material, its main chemical composition is as follows:

Copper 5.50%, lead 32.13%, zinc 4.50%, arsenic 6.82%, sulfur 6.35%. The main phases contained in the smelting white smoke are lead sulfate, zinc sulfate, copper sulfate, etc.

The blast furnace bag ash and converter dust ash pretreated in a steel plant were used as raw materials. The steel dust sludge was washed and desalted to obtain washed steel dust sludge raw materials. The washed steel dust sludge raw materials were dried in a vacuum drying oven to a moisture content of 8% to obtain pretreated dechlorinated dust sludge.

Its main chemical components are as follows.

Blast furnace bag ash: carbon 26.01%, total iron 38.54%, ferric oxide 46.80%, ferrous oxide 7.43%, zinc oxide 3.94%, silicon dioxide 5.65%, calcium oxide 1.82%, magnesium oxide 1.59%, aluminum oxide 3.19%, sodium oxide 0.29%, potassium oxide 0.19%, etc.

Converter dust removal ash: carbon 1.02%, total iron 52.20%, ferric oxide 70.44%, ferrous oxide 3.72%, zinc oxide 2.57%, silicon dioxide 0.91%, calcium oxide 11.44%, magnesium oxide 1.01%, aluminum oxide 0.11%, sodium oxide 0.36%, potassium oxide 0.49%, etc.

The main ingredient of steel dust is iron, and the mass ratio of converter dust: blast furnace bag ash is 7:3~8:2.

S2. Pre-treated steel dust, lead-containing waste slag, waste glass, self-produced fly ash, and high-speed iron materials are mixed into various materials in a certain proportion using the mass batching method to form a mixture.

S3. The mixed material is sent to a fully automatic hydraulic forming brick making machine to form mixed bricks for standby use. During the brick making process, the material is pre-watered to maintain appropriate humidity and is directly pressed into shape without adding other adhesives.

S4, bricks, reducing agents, and returned slag are sent to the roasting equipment, and after uniform distribution, they are roasted in a reducing atmosphere. Impurities such as Fe, Si, Ca, and Al in the steel dust can be used as flux or slag-making agents. Carbon is used as fuel and reducing agent to participate in the reduction smelting process of the materials in the furnace. Iron can also be used as a sulfur-making agent to reduce the sulfur content of the floating slag. The returned slag plays a role in stabilizing the furnace condition. The roasting temperature is 1200~1400℃. After the smelting is completed, the reaction materials in the furnace form molten liquid in a layered state at the bottom of the furnace body. The crude lead is located in the lower layer, and the slag floats on the upper layer and is stored after water cooling. The intermediate transition zone is low-grade matte. The flue gas is discharged after dust collection and desulfurization. Crude lead, water-quenched slag, and low-grade matte can all be sold as products, and no new solid waste is generated.

Embodiment 1:

As a comparative example, without adding steel dust, iron powder is used as raw material to co-dispose of lead-containing waste slag, smelting white smoke, waste glass, iron powder, and various materials are added into a mixture in a certain proportion, and the adding proportions of smelting white smoke, waste glass, and iron powder are 65%, 5%, and 30% respectively. The lead grade of the mixed brick material is 18%, the copper grade is 6%, and the sulfur grade is 8%; the mixed brick material is returned to the roasting furnace, the roasting temperature in the tuyere zone is 1200~1400℃, the oxygen enrichment concentration is 25%, and the coke ratio is optimized and adjusted so that the furnace condition and product indicators meet the requirements. Under this condition, the coke ratio is 20%, the crude lead yield is 18%, the lead grade of the water-quenched slag is less than 1%, and the copper grade of the water-quenched slag is less than 0.5%.

Embodiment 2:

The pretreated converter dust is used to replace part of the iron powder at a ratio of 1:1. The pretreated converter dust, smelting white smoke, waste glass and iron powder are added into various materials in a certain proportion to form a mixture. The addition ratios are 15%, 65%, 5% and 15%. The lead grade of the mixed bricks is 18%, the copper grade is 6% and the sulfur grade is 8%. The mixed bricks are returned to the roasting furnace, the roasting temperature in the tuyere zone is 1200~1400℃, the oxygen enrichment concentration is 25%, and the coke ratio is optimized and adjusted to make the furnace condition and product indicators meet the requirements. Under this condition, the crude lead yield is 18%, the lead grade of the water-quenched slag is less than 1%, the copper grade of the water-quenched slag is less than 0.5%, and the coke ratio remains at 20% without change.

Under this condition, the annual additional benefits are estimated as follows:

Taking the lead smelting annual disposal scale of 150,000 tons/year as an example, the iron powder addition ratio is 30%. According to the 15% after replacement, it is estimated that 22,500 tons of iron powder can be saved each year. The average purchase price of iron powder is 1,000 yuan/ton, and the annual iron powder purchase cost can be saved by 22.5 million yuan;

Embodiment 3:

The converter dust removal ash and blast furnace bag ash are mixed in a ratio of 7:3. The chemical composition of the mixture is 9.77% carbon, 58.16% ferric oxide, 4.39% ferrous oxide, 2.69% zinc oxide, 2.33% silicon dioxide, 8.13% calcium oxide, 1.08% magnesium oxide, 1.13% aluminum oxide, 0.34% sodium oxide, 0.38% potassium oxide, etc. 50% of the iron powder is replaced by the mixed material, and the pre-treated converter dust and blast furnace bag ash, smelting white smoke, waste glass, and iron powder are added into various materials in a certain proportion to form a mixture. The adding proportions are 15%, 65%, 5%, and 15%. The lead grade of the mixed brick material is 18%, the copper grade is 6%, and the sulfur grade is 8%. The mixed brick material is returned to the roasting furnace, the roasting temperature in the tuyere zone is 1200~1400℃, the oxygen enrichment concentration is 25%, and the coke ratio is optimized and adjusted to make the furnace condition and product indicators meet the requirements. Under this condition, the crude lead yield is 18%, the lead grade of the water-quenched slag is less than 1%, the copper grade of the water-quenched slag is less than 0.5%, and the coke ratio is reduced to 17% under stable conditions.

Under this condition, the annual additional benefits are estimated as follows:

① Taking the lead smelting annual disposal scale of 150,000 tons/year as an example, the coke addition ratio is 20%. According to the 17% after replacement, 4,500 tons of coke can be saved each year. The average purchase price of coke is 2,000 yuan/ton, and the annual coke purchase cost is saved by 9 million yuan;

② Taking the annual lead smelting scale of 150,000 tons/year as an example, the iron powder addition ratio is 30%. According to the 15% after replacement, it is estimated that 22,500 tons of iron powder can be saved each year. The average purchase price of iron powder is 1,000 yuan/ton, and the annual iron powder purchase cost is saved by 22.5 million yuan;

③After replacement, the direct procurement cost can be saved by (900+2250)=31.5 million yuan.

The advantages of the present invention are:

1. The raw materials required by the present invention are hazardous wastes and general industrial solid wastes. The cost of using a single disposal method is high. If not disposed of in time, the environmental damage is relatively large;

2. The resource utilization method provided by the present invention has an annual output of more than 10 million tons of steel dust and lead-containing waste slag, and the source of raw materials is very wide;

3. The present invention performs synergistic treatment on steel dust and lead-containing waste slag. Impurities such as Fe, Si, Ca, and Al in the steel dust can be used as flux or slag-making agent for smelting lead-containing waste slag. Carbon is used as fuel and reducing agent to participate in the reduction reaction of materials in the furnace. The synergy between the raw materials is high, and the purpose of treating waste with waste is achieved.

4. The raw material cost of the present invention is relatively low, and the use of steel dust to replace part of the additives and reducing agents can greatly reduce the disposal cost of lead-containing waste slag, with significant economic benefits;

5. The crude lead, low-grade matte and water-quenched slag produced by the present invention can all be used as products, without generating any new solid waste, thus achieving complete comprehensive utilization of solid waste.

The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims (4)

1. A resource utilization method for the coordinated disposal of lead-containing waste slag by steel dust and mud, characterized by comprising: The steel dust sludge is subjected to water washing, desalting, dehydration and drying to obtain dechlorinated dust sludge; wherein the water content of the dechlorinated dust sludge is less than 10%, the carbon grade is not less than 10%, and the iron grade is not less than 55%; Dechlorinated dust sludge, lead-containing waste slag, waste glass and high-iron materials are batched, mixed and block-formed to obtain mixed brick materials; wherein the waste glass is discarded lead-containing glass, and the proportion of the waste glass is 5-10wt%; the high-iron materials include at least one of pyrite slag, iron-rich slag of hydrometallurgy, iron powder and iron-rich tailings, and the iron grade of the high-iron materials is not less than 55%, and the sulfur grade is not higher than 8%; the proportion of the dechlorinated dust sludge and high-iron materials is 20-40wt%, and the proportion of the dechlorinated dust sludge in the dechlorinated dust sludge and high-iron materials is not more than 80%; the lead grade of the mixed material after the dechlorinated dust sludge, lead-containing waste slag, waste glass and high-iron materials is 10-20%, the copper grade is less than 10%, and the sulfur grade is not higher than 10%; The mixed brick material, reducing agent and returned slag are sent to the roasting equipment, evenly distributed, and roasted at 1200-1400℃ in a reducing atmosphere. After smelting, crude lead, water-quenched slag and low-grade matte are obtained respectively. 2. The resource utilization method of lead-containing waste slag by co-disposing of steel dust and mud as described in claim 1 is characterized in that before batching, the raw materials with large particle sizes are crushed so that the particle size of each raw material is not more than 5 mm. 3. The resource utilization method of lead-containing waste slag by coordinated treatment of steel dust and mud as described in claim 1 is characterized in that the flue gas generated during the roasting process is dust collected, the collected self-produced ash is used for batching, and the flue gas after dust collection is desulfurized and then discharged in compliance with the emission standards. 4. The resource utilization method of lead-containing waste slag co-processed with steel dust and mud as described in claim 1 is characterized in that the obtained crude lead, water-quenched slag and low-grade matte are reprocessed or sold.