CN111733325A - A method for comprehensive recovery of valuable metals from copper-based solid waste - Google Patents

Abstract

The invention discloses a method for comprehensively recovering valuable metals from copper-based solid waste, comprising the following steps: uniformly mixing and batching copper-based solid waste, coal and flux, and performing reduction smelting to produce blister copper, reduction slag and smoke dust. 1; the output blister copper is subjected to anode refining, the fuel rate is 5-15%, and the slagging rate is 3-30% to obtain copper anode plates, refining slag, and soot 2; the output refining slag is acid leached to obtain electricity; Copper, leaching residue 1. The invention can not only separate copper in copper-based solid waste efficiently, but also treat heavy metal solid waste such as waste copper, secondary zinc oxide smoke and tin slag, and realize the purpose of comprehensive and efficient recovery of copper, zinc, lead and tin in the whole process.

Description

A method for comprehensive recovery of valuable metals from copper-based solid waste

technical field

The invention relates to the recovery of copper-based solid waste, in particular to a method for comprehensively recovering valuable metals from copper-based solid waste.

Background technique

The sources of copper-based solid waste are wide, mainly including various waste residues produced by non-ferrous smelting, such as copper soot, black copper mud, anode mud, lead matte, polymetallic matte, etc. Recycled copper, such as copper-containing electroplating sludge, copper in scrap wire and cable or circuit boards, etc. These copper-based solid wastes are complex in composition, not only containing high-value copper, but also high-value impurity metals such as lead, zinc and tin. Improper handling will cause huge damage to the environment; and the copper content in copper-based solid waste varies greatly , the copper grade of copper powder, sponge copper and copper mud is 60-90%, while the copper content of electroplating sludge and environmental protection mud is mostly below 15% or even lower. At present, the recovery of valuable metals from copper-based solid waste has attracted widespread attention at home and abroad. In 2016, the global production of recycled copper can meet 47.5% of the market demand. my country is the world's largest producer and consumer of refined copper, but my country's consumption of copper produced from copper-based solid waste accounts for only 28.57%, which is significantly lower than the world's advanced level. Therefore, no matter from the perspective of environmental protection or resources, the proper treatment of copper-based solid waste can not only alleviate the tension of copper, zinc, lead and tin metals in my country, but also has important strategic significance for the development of the national economy, and is also the sustainable development of my country's heavy non-ferrous metal industry. the only way.

At present, there are two main methods for treating copper-containing solid waste at home and abroad, hydrometallurgy and pyrometallurgy. The American Outfront Company uses a full wet process to treat copper-containing waste residues, and the recovery of copper, gold and silver can reach 99%. However, the all-wet process has a long process flow and poor adaptability to raw materials. Pyrometallurgy can realize the coordinated smelting of copper-based solid waste and copper concentrate. For example, Belgian Umicore and Japan Dowa Co., Ltd. respectively use Isa furnace and Osmelt furnace to treat scrap copper, waste circuit boards and other wastes. The smelting efficiency is high, but the investment is expensive. In order to reduce costs, domestic research on pyrometallurgical processing of copper-containing wastes mainly focuses on the development of secondary copper smelting equipment suitable for national conditions and the transformation of traditional smelting equipment. For example, Ruilin Engineering Technology Co., Ltd. combines the characteristics of tilting furnace and rotary anode furnace to develop an NGL furnace suitable for copper-containing waste treatment, which has simple structure, high thermal efficiency, and convenient feeding and slag removal. However, the NGL furnace is currently mainly used to treat copper-containing waste with a grade of more than 80%, and it is difficult to treat low-grade copper-based solid waste.

Few patents in the prior art adopt the combination of hydrometallurgy and pyrometallurgy, and the patent publication number CN1093756A proposes a combination of wet and dry processes to recover tin, copper and lead from copper smelting waste slag. , zinc and other metals, using submerged arc furnace to reduce and smelt copper slag at high temperature to produce zinc oxide powder and alloys of tin, lead, copper and iron, which are oxidized roasting and selective sulfuric acid leaching to produce two Tin oxide, lead sulfate mixed slag and copper sulfate, ferric sulfate mixed solution, tin and lead slag are desulfurized and then reduced and smelted to obtain solder, and the mixed solution is subjected to iron removal by jarosite method and then sent to electrolysis to obtain electrolytic copper. The patent adopts electric furnace oxidation smelting to bring all valuable metals into the alloy in one step. Electric furnace smelting does not separate copper from other metals, and electric furnace consumes high energy. In this patent, the alloy is first smelted, and then all metals are leached by sulfation roasting and leaching, and the equipment requires anti-corrosion, which has high requirements for equipment, is not suitable for industrial application, and has high energy consumption. The obtained mixed solution contains copper sulfate and Ferric sulfate, the leaching rate of copper is 96.5%, and the leaching rate of iron is 65%, and further separation is required in the follow-up. At the same time, this patent can only deal with copper slag alone, and cannot recover other metals simultaneously, and is only suitable for dealing with low-grade copper-containing materials.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is: to solve the problems existing in the above-mentioned prior art, and to provide a method for comprehensively recovering valuable metals from copper-based solid waste, adopting the combination of hydrometallurgy and pyrometallurgy, first by reducing Smelting preferentially enriches copper, then carries out anode refining, directly leaches copper with acid, gives priority to copper recovery, reduces energy consumption, and avoids the use of equipment with high anti-corrosion requirements, which is suitable for industrial applications.

The technical scheme adopted in the present invention is:

A method for comprehensively recovering valuable metals from copper-based solid waste is characterized in that comprising the following steps:

Reduction smelting: The copper-based solid waste, coal and flux with a mass ratio of 100:10-20:2-20 are uniformly mixed and batched for reduction smelting. The oxygen-enriched concentration is 30%-75%, and the oxygen-to-material ratio is 100-200Nm3/ t, the oxygen-to-coal ratio is expressed by the combustion coefficient, the oxygen-to-coal ratio is controlled at 0.5-0.9, the reduction temperature is 1150-1350°C, and the reduction time is 1-3h, producing blister copper, reduction slag, and soot 1;

Anode refining: blister copper is subjected to anode refining, the fuel rate is 5-15%, and the slagging rate is 3-30% to obtain copper anode plate, refining slag, and soot 2;

Copper hydrometallurgy: acid leaching is used for the produced refining slag, the liquid-solid ratio is controlled to be 1-5L/kg, the acid concentration is 50-200g/L, the leaching temperature is 30-90°C, and the leaching time is 1-4h. Copper Leachate and Leaching Residue 1.

In the invention, copper is preferentially recovered through reduction smelting in a side-blown furnace. After anode refining, the refining slag contains 30-35% copper, and the refining slag contains 1-3% iron. Most of the copper in the refining slag exists in the form of oxides, which are easily destroyed by Acid leaching is efficient for recovery, without the need to use equipment with high anti-corrosion requirements, and is suitable for industrial applications. At the same time, lead and tin are enriched in the leaching slag 1, which is convenient for subsequent recycling of lead and tin.

Preferably, the oxygen-enriched concentration of reduction smelting is 40-75%, the oxygen-to-material ratio is 100-150Nm ³ /t material, the oxygen-to-coal ratio is expressed by the combustion coefficient, controlled at 0.75-0.9, and the reduction temperature is controlled at 1250-1350°C. Further preferably, the oxygen-enriched concentration of reduction smelting is 60-75%.

Preferably, copper scrap is also added in the anode refining step, the fuel rate is controlled by 6-10%, and the slagging rate is controlled by 3-20%. Further preferably, scrap copper is added in the anode refining step, the fuel rate is controlled by 6-8%, and the slagging rate is controlled by 3-15%. The scrap copper is purchased from outside, and the scrap copper is treated together to increase the output of refining slag and improve the utilization rate of copper.

Further, the step of smelting the reducing slag is also included after the reduction smelting: the reducing slag is smelted with vulcanizing agent, tin slag, pulverized coal, and flux, and the mass ratio of the reducing slag and vulcanizing agent, tin slag, pulverized coal, and flux is: 70-80: 10-20: 10-30: 20-30: 10-20, the sulfur content of the vulcanizing agent is 25%-40%, the tin slag content is 1%-8%, and the oxygen concentration is 21%-45%, the oxygen-to-coal ratio is expressed by the combustion coefficient, controlled at 0.5-0.8, the temperature is 1250-1350°C, and the fuming time is 1-3h to obtain smelting slag, matte and soot 3. Preferably, in the step of smelting the reduced slag, the oxygen-enriched concentration is 21%-30%, and the oxygen-to-coal ratio is represented by a combustion coefficient, which is controlled at 0.65-0.75.

Further, after the reduction smelting, the zinc hydrometallurgy is also included: the soot 1, the soot 2 and the soot 3 are recovered by acid leaching, and the liquid-solid ratio is controlled to be 1-5L/kg, the acid concentration is 30-100g/L, and the leaching temperature The temperature is 20-80°C, and the leaching time is 1-4h, to obtain electrozinc and leaching residue 2. Preferably, the liquid-solid ratio is controlled to be 1-4L/kg, the sulfuric acid concentration is 30-80g/L, the leaching temperature is 40-80°C, and the leaching time is 1-3h.

Further, after the zinc hydrometallurgy also includes a step of smelting the leaching slag 1 and the leaching slag 2: adding the leaching slag 1 and the leaching slag 2 to a reducing agent and a flux for smelting, and the amount of the reducing agent exceeds 1%-5% of the theoretical amount, The flux rate is 5%-15%, the melting temperature is 1300 DEG C-1500 DEG C, and the melting temperature is 3-5 hours to obtain lead-tin alloy and electric furnace slag. High-grade tin-containing and lead slag can be directly obtained by smelting lead-tin alloy. Preferably, the smelting control reducing agent dosage exceeds the theoretical dosage by 1%-3%, the flux rate is 10%-15%, and the smelting temperature is 1300°C-1400°C.

Further, before the copper hydrometallurgy process, the refining slag is crushed and then passed through a 200-mesh sieve, and the particle size is controlled to be above 98%.

Further, the flue gas 3 is obtained from the reduction slag smelting flue gas through the dedusting step, and the dedusted reducing slag smelting flue gas is used for leaching refining slag, flue dust 1, flue dust 2 and flue dust 3 after acid production.

Further, the mass percentages of Cu, Pb, Zn and Sn in the copper-based solid waste are respectively 3%-40%, 1%-10%, 2%-30%, 1%-8%, and copper Copper exists in the form of oxides in the base solid waste.

Among them, copper-based solid waste side-blown furnace reduction smelting, the main reactions are (1)-(3):

2C+O ₂ =2CO (1)

MeO+C=Me+CO (2)

MeO+CO=Me+CO ₂ (3)

Me refers to metals such as Cu, Zn, Sn, Pb, etc.

Side-blown sulfidation smelting of reducing slag, the main reactions are (4)-(6):

4SnO+3S ₂ =4SnS+2SO ₂ (4)

PbO+C=Pb+CO (5)

ZnO+C=Zn+CO (6)

The SnS volatilized by the fumigation and vulcanization of the side-blown furnace is oxidized at the secondary combustion point of the flue gas rising flue, and the main reaction is (7):

2SnS+3O ₂ =2SnO+2SO ₂ (7)

For blister copper anode refining, the main reactions are (8)-(9):

2Me+O ₂ =2MeO (8)

MeO+SiO ₂ =MeO·SiO ₂ (9)

Me refers to metals such as Cu, Zn, Sn, Pb, etc.

Wet leaching of copper from refining slag, the main reaction is (10):

CuO+H ₂ SO ₄ =CuSO ₄ +H ₂ O (10)

Soot 1, Soot 2, Soot 3 Wet leaching of zinc, the main reaction is (11): ZnO+H ₂ SO ₄ =ZnSO ₄ +H ₂ O (11)

Electric furnace smelting, the main reactions are (12)-(13):

SnO+C=Sn+CO (12)

PbO+C=Pb+CO (13)

The raw material of the invention has strong applicability, can handle low, medium and high grade copper-based solid waste, and can treat different grades of waste miscellaneous copper at the same time. The reduction smelting can be carried out first to effectively enrich and separate copper.

The advantages of the invention are that the oxygen-enriched side-blown reduction furnace is used to preferentially recover copper, and the oxygen-enriched side-blown fume furnace co-processes the reduction slag, and the tin slag is fumed, sulfurized and volatilized to obtain high-grade tin-containing fume, and the copper in the refining slag and various soots Most of the zinc in it exists in the form of oxides, which are easily recovered by sulfuric acid leaching and efficiently recovered. At the same time, lead and tin are further enriched in the leaching slag. The SO ₂ flue gas can be used for leaching copper from refining slag and leaching zinc from smoke dust after acid making, which reduces the leaching cost. The generated fumed slag is sent to the cement plant, and the matte is sold out. The cascade comprehensive and efficient recycling of copper, zinc, lead and tin in the whole process.

Description of drawings

FIG. 1 is a flowchart of Embodiment 1. FIG.

specific implementation

In order to better understand the above technical solutions, the above technical solutions will be described in detail below with reference to the accompanying drawings and specific embodiments.

Example 1

The mass percentage content of Cu in the copper-based solid waste selected in this embodiment is 19.5%, Pb 3.2%, Zn 3.5%, Sn 3.5%; the mass percentage content of carbon in the coal is 75%, and the ash content is less than 10%; The flux includes quartz stone and limestone, of which more than 90% are quartz stone, the mass percentage content of _SiO2 in the quartz stone is 85.5%, and the CaO content in the limestone is 51.3%; the purchased scrap copper contains Cu 80%, Pb 2.5%, Zn 6%, Sn 10%, vulcanizing agent contains S 31.3%, Zn 1.3%, FeO 61.5%, tin dross contains Sn 4.5%, Pb 2.6%, Cu 3.5%, Zn 2.5%, zinc oxide dust contains 55% Zn , Pb2.5%, FeO 20.2%.

As shown in Figure 1, 100kg of copper-based solid waste, 15kg of coal, and 5kg of flux are evenly mixed and added to the oxygen-enriched side-blown furnace for reduction and smelting. The oxygen-enriched concentration with an oxygen concentration of 65% is blown in. The oxygen-enriched concentration is the concentration ratio of oxygen to the entire gas. The oxygen-to-material ratio is controlled at 130Nm ³ /t material, the oxy-coal combustion coefficient is controlled at 0.75, and the reduction smelting temperature is controlled at 1250 ° C , smelting for 2.5h, producing 20.1kg of blister copper, which contains Cu 89%, Pb 4.7%, Zn 2.1%, Sn 2.8%, and reduced slag 79.9kg, which contains Cu 1.8%, Pb 1.5%, Zn 0.6%, Sn 3.3%, the mass of soot 1 is 11.0kg, which contains Cu 4.3%, Pb 5.5%, Zn 23.9%, Sn 4.8%.

79.9kg of reduced slag in hot state enters the oxygen-enriched side-blown smoke furnace. The top of the oxygen-enriched side-blown smoker is provided with a vulcanizing agent port and a tin slag port. Add 15kg of vulcanizing agent, 14.8kg of flux, infuse oxygen-rich with an oxygen concentration of 21%, inject 25kg of pulverized coal for fumigation, vulcanization, volatilization and smelting. 3h, 110kg of smelting slag is produced, which contains Cu 0.4%, Pb 0.3%, Sn 0.26%, and matte 13.5kg, which contains Cu 15%, Fe35.9%, S 25%, reducing slag smelting flue gas is dedusted by cloth bag Soot 3 is obtained, and the dedusted reducing slag smelting flue gas is used for leaching refining slag, soot 1, soot 2 and soot 3 after acid production. The mass of the soot 3 is 19.6 kg, which contains Cu 0.4%, Pb 7.0%, Sn 16.5%, and Zn 5%.

Blister copper and purchased scrap copper are used for anode refining, heavy oil is used as fuel, SiO and CaO are added to make slag, and copper anode plates, refining slag, and soot 2 are obtained. The proportion of the total weight, the fuel rate is 7%, the slagging rate is the proportion of the obtained refining slag to the total weight of the blister copper and the purchased scrap copper, the slagging rate is 10%, and the outputted anode copper contains copper The amount is more than 98.5%, the refining slag contains 30% copper, and the refining slag contains 1% iron; after the refining slag is crushed, the particle size is controlled to be more than 98% and passes through a 200-mesh sieve. After crushing, the slag is leached with sulfuric acid. /kg refining slag, sulfuric acid concentration 80g/L, leaching temperature 60°C, leaching time 4h, copper leaching rate 99.5%, electrolytic copper was obtained after electrolysis, and lead and tin were enriched in leaching slag 1.

Soot 1, soot 2, soot 3 are combined with secondary zinc oxide soot and then leaching zinc with sulfuric acid. The rate is 99.8%, and lead and tin are enriched in the leaching residue 2.

The leaching slag 1 and leaching slag 2 are mixed and then smelted in an electric furnace. The total mass percentage of lead and tin in the leaching slag is 45%. Anthracite or coke is used as the reducing agent. 2% of the dosage, the flux rate is the proportion of the flux to the total weight of leaching slag 1 and leaching slag 2, the flux rate is 12%, the smelting temperature is 1300 ° C, smelting for 4 hours, the total mass percentage of the lead-tin alloy produced is 98%, and the recovery rate is 98%. It is 95%, and the electric furnace slag contains 2.5% tin, which is returned to the smoke furnace for ingredients.

Claims (10)

1. a method for comprehensive recovery of valuable metals from copper-based solid waste, is characterized in that comprising the following steps: Reduction smelting: The copper-based solid waste, coal and flux with a mass ratio of 100: 10-20: 2-20 are uniformly mixed and batched for reduction smelting. The oxygen-enriched concentration is 30%-75%, and the oxygen-to-material ratio is 100-200Nm ³ /t, the oxygen-coal ratio is expressed by the combustion coefficient, the oxygen-coal ratio is controlled at 0.5-0.9, the reduction temperature is 1150-1350°C, and the reduction time is 1-3h, producing blister copper, reduction slag, and soot 1; Anode refining: blister copper is subjected to anode refining, the fuel rate is 5-15%, and the slagging rate is 3-30% to obtain copper anode plate, refining slag, and soot 2; Copper hydrometallurgy: the refining slag produced is acid leached, the liquid-solid ratio is controlled to be 1-5L/kg, the acid concentration is 50-200g/L, the leaching temperature is 30-90°C, and the leaching time is 1-4h. Copper Leachate and Leaching Residue 1. 2. the method for comprehensive recovery of valuable metals from copper-based solid waste as claimed in claim 1, is characterized in that after reduction smelting, also comprises the step of smelting reduction slag: reducing slag and vulcanizing agent, tin slag, powder Coal and flux are smelted, and the mass ratio of reducing slag to vulcanizing agent, tin slag, pulverized coal, and flux is 70-80:10-20:10-30:20-30:10-20, and the mass percentage of sulfur in the vulcanizing agent is 25%-40%, the mass percentage of tin in tin slag is 1%-8%, the oxygen-enriched concentration is 21%-45%, the oxygen-to-coal ratio is expressed by the combustion coefficient, controlled at 0.5-0.8, the temperature is 1250-1350 ℃, the smoke The melting time is 1-3h to obtain smelting slag, matte and smoke 3. 3. the method for comprehensively reclaiming valuable metals from copper-based solid waste as claimed in claim 2, is characterized in that after reduction smelting also comprises zinc hydrometallurgy: soot 1, soot 2 and soot 3 adopt acid leaching to reclaim zinc , the liquid-solid ratio is controlled to be 1-5L/kg, the acid concentration is 30-100g/L, the leaching temperature is 20-80°C, and the leaching time is 1-4h to obtain electrozinc and leaching residue 2. 4. the method for comprehensively recovering valuable metals from copper-based solid waste as claimed in claim 3, is characterized in that after the zinc hydrometallurgy also comprises the smelting steps to leaching slag 1 and leaching slag 2: leaching slag 1, leaching Slag 2 is smelted by adding reducing agent and flux. The amount of reducing agent exceeds 1%-5% of the theoretical amount, and the flux rate is 5%-15%. slag. 5. the method for comprehensively recovering valuable metals from copper-based solid waste as claimed in any one of claims 1-4, is characterized in that before the copper hydrometallurgy also comprises 200 mesh sieves after the refining slag is broken, particle size Control over 98%. 6. The method for comprehensively recovering valuable metals from copper-based solid waste as claimed in claim 2, wherein the soot 3 is obtained through the dedusting step for reducing slag smelting flue gas, and the reducing slag smelting flue gas after dedusting is processed After acid, it is used for leaching refining slag, soot 1, soot 2 and soot 3. 7. The method for comprehensively recovering valuable metals from copper-based solid waste according to any one of claims 1-4, wherein the mass percentages of Cu, Pb, Zn, Sn in the copper-based solid waste are respectively It is 3%-40%, 1%-10%, 2%-30%, 1%-8%, and copper exists in the form of oxides in copper-based solid waste. 8. The method for comprehensively recovering valuable metals from copper-based solid waste as claimed in any one of claims 1-4, characterized in that: the oxygen-rich concentration of reduction smelting is 40-75%, and the oxygen-to-material ratio is ^100-150Nm /t material, the oxygen-coal ratio is expressed by the combustion coefficient, which is controlled at 0.75-0.9, and the reduction temperature is controlled at 1250-1350 °C. 9. The method for comprehensively recovering valuable metals from copper-based solid waste according to any one of claims 2-4, wherein the oxygen-enriched concentration is 21%-30% in the step of smelting the reduced slag, and the oxygen-rich concentration is 21%-30%. The coal ratio is expressed by the combustion coefficient, which is controlled at 0.65-0.75. 10. The method for comprehensively recovering valuable metals from copper-based solid waste as claimed in any one of claims 1-4, characterized in that: in the anode refining step, copper scrap is also added, and the fuel rate is controlled by 6-10% , Control the slag making rate 15-25%.

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