Recycling method for synergistically treating lead matte by arsenic sulfide slag

Abstract

The invention discloses a recycling method for synergistically treating lead matte by arsenic sulfide slag. According to the method, the sulfur-loving property of copper in the arsenic sulfide waste residues is utilized, firstly, the arsenic sulfide waste residues are added into oxygen pressure leaching liquid of the pyrogenic process lead smelting by-product lead matte, CuS precipitates are generated to recover copper, and arsenic is converted into arsenic acid to enter a liquid phase; thirdly, arsenic sulfide slag is added into the arsenic leaching solution again, arsenic acid is reduced into arsenious acid through the reducibility of sulfide, and an arsenious acid solution is obtained; sodium sulfite is added into the arsenious acid solution, Sb < 5 + > and Bi < 5 + > in the arsenious acid solution are reduced into Sb < 3 + > and Bi < 3 + >, co-precipitation of AsSbO4, BiSbO4 and BiSbO7 is avoided, and separation of arsenic, antimony and bismuth is effectively achieved. And finally, treating the arsenic-rich liquid through natural cooling crystallization to obtain the electronic-grade white arsenic crystal. The method is easy and convenient to operate, the problems that the arsenic sulfide slag is large in harm and difficult to treat are solved, efficient utilization of dangerous solid waste and resourceful treatment of arsenic are achieved, and the method has important significance and practical value for improving comprehensive recycling of enterprise resources and economic benefits.

Description

Technical Field

[0001] The invention belongs to the field of comprehensive utilization of nonferrous smelting resources, and specifically relates to a resource utilization method for collaboratively processing lead matte with arsenic sulfide slag. Background Art

[0002] my country is a major copper smelting country. More than 60% of copper concentrate needs to be imported from abroad. The proportion of complex materials, especially high-arsenic materials, is increasing. According to statistics, the amount of arsenic entering the copper smelting system in China reaches tens of thousands of tons each year, and most of them are finally produced in the form of arsenic sulfide slag. The mass fraction of As in arsenic sulfide slag is as high as 10%~55%, which has high leaching toxicity and strong corrosiveness. It is a highly toxic substance. If not properly treated, it will cause serious pollution to the environment. At present, arsenic-containing waste slag is mainly landfilled, but it is difficult to achieve stable solidification of arsenic in landfill treatment. Arsenic sulfide slag will gradually oxidize and decompose, releasing arsenic into water or soil, and secondary pollution is extremely serious. It can be seen that the comprehensive recovery and treatment of arsenic sulfide slag is of great significance. At the same time, lead matte is a by-product of pyrometallurgical lead smelting, which contains valuable elements such as copper, lead, and arsenic. It has a large output and a high content of valuable elements, but its chemical composition is complex and difficult to handle. At present, pyrometallurgical process is mostly used for treatment, but its resource recovery rate is low and it has great harm to the environment. Therefore, how to dispose of lead matte cleanly and efficiently is also a major problem currently faced.

[0003] At present, there are two main treatment processes for arsenic sulfide waste residues. One is to stabilize the harmful elements in the arsenic sulfide waste residues and then solidify and landfill them to reduce the pollution risk of the waste residues. The other is to utilize them as resources. Resource utilization is divided into two major processes: pyrometallurgy and hydrometallurgy. Among them, the pyrometallurgy process is mainly roasting: it is divided into oxidation roasting, reduction roasting or vacuum roasting, which oxidizes or reduces arsenic to volatile As2O3 to achieve separation from other elements. Although this method has low cost, simple process and mature technology, the purity of the product is low and it causes serious pollution to the atmosphere. It has been gradually eliminated (CN106756113A). The wet process mainly includes iron salt leaching method (CN110394354A), copper sulfide replacement method (CN109055759A), hydrogen peroxide / oxygen pressure leaching method (CN116065025A), acid leaching method (CN115557533A) and alkaline leaching method (CN107312928A), etc., which mainly produce As2O3, arsenate and metallic arsenic for arsenic fixation. However, there are many shortcomings in general, such as iron salt leaching method and copper sulfide replacement method need to consume a large amount of iron salt and copper powder, and iron and copper recovery is difficult and costly.

[0004] On the other hand, major smelting enterprises at home and abroad usually use lead matte with high copper content (Cu≥30%) as raw material for copper smelting to enter the converter for blowing to produce crude copper, and the lead volatilizes into the gas phase to obtain oxide dust. There are many disadvantages such as long process flow, low metal recovery rate, serious environmental pollution and high production cost. For lead matte with low copper content (Cu<30%), the traditional wet process is to first carry out oxidative roasting desulfurization to convert copper into copper oxide or copper sulfate, and then carry out sulfuric acid leaching. The copper sulfate solution is electrolytically deposited to obtain electrolytic copper, and the lead sulfate leaching slag is returned to the lead system. The main problem of this process is that the low-concentration SO2 flue gas generated by the oxidative roasting process is difficult to produce acid, which seriously pollutes the ecological environment, and improper roasting temperature control can easily lead to material sintering, high roasting sand residue rate, and a significant reduction in metal recovery rate. Enterprises such as Jingui Silver Industry and Huludao Lead and Zinc Smelter use oxygen pressure leaching-extraction-electrolytic deposition to treat lead matte. The process flow is long, the investment is large, and the operating cost is high.

[0005] Therefore, in view of the shortcomings of the existing lead matte and arsenic sulfide slag treatment technology, a resource recovery method for the coordinated treatment of lead matte and arsenic sulfide slag is provided, which is simple to operate, low-cost and environmentally friendly. This method can not only comprehensively recover metal elements, but also effectively solve the problem of resource recovery of arsenic-containing waste and copper-containing materials and safe disposal of arsenic. It has a very important leading and exemplary significance for solving the common problems of green and efficient recovery of lead matte resources, reduction, harmlessness and resource utilization of arsenic-containing materials and copper-containing materials in the non-ferrous metal industry. Summary of the invention

[0006] The present invention is based on the perspective of comprehensive resource utilization and safe disposal of hazardous wastes, and aims to provide a resource recovery method for lead matte by co-processing arsenic sulfide slag. Based on the differences in sulfur / oxygen affinity of valuable elements such as lead, copper, and arsenic, the arsenic sulfide slag and lead matte produced by the enterprise are used for co-processing, arsenic is selectively separated from arsenic-containing materials and copper in lead matte is recovered, copper and lead antimony are separated, and arsenic is produced in the form of As2O3, realizing the resource recovery of arsenic. The method is simple to operate, low in cost, and effectively consumes hazardous solid waste generated in the production process of the enterprise, which meets the requirements of waste management, resource utilization and green sustainable development, and the entire process can realize the full reuse of wastewater, and the resource recovery and reduction of harmful elements, which is suitable for industrial application.

[0007] In order to achieve the above technical purpose, the technical solution adopted by the present invention includes the following steps:

[0008] 1) Lead matte oxygen pressure leaching: the lead matte is dried, crushed and ground, and then passed through a 120-mesh sieve for standby use. An appropriate amount of lead matte powder is added to a pre-prepared sulfuric acid solution, and then the mixture is poured into an autoclave, and oxygen is introduced for oxygen pressure leaching to obtain a copper-containing leaching solution and a lead-containing leaching slag; the lead-containing leaching slag is returned to the lead smelting system;

[0009] 2) Copper precipitation with arsenic sulfide slag: the copper-containing leaching solution obtained in step 1) is added with arsenic sulfide slag at a certain copper-arsenic ratio according to the copper content therein, and the reaction obtains arsenic-containing filtrate and copper sulfide slag; the copper sulfide slag is returned to the copper smelting system;

[0010] 3) Arsenic sulfide slag reduction: The arsenic-containing filtrate obtained in step 2) is added with arsenic sulfide waste slag according to the arsenic content in the filtrate and a certain sulfur-arsenic ratio is used to reduce the arsenic sulfide slag. 2- The reducing property of the arsenic acid is used to reduce the arsenic acid to arsenous acid, and the residual copper in step 2) is further precipitated at the same time. After the reaction is completed, a reduction slag mainly composed of copper sulfide and an arsenous acid solution are obtained; the reduction slag can be returned to step 2) to reduce the copper together with the arsenic sulfide slag;

[0011] 4) Sodium sulfite reduction: Add sodium sulfite to the arsenic acid solution obtained in step 3) to reduce the Sb 5+ 、Bi 5 + Restore to Sb 3+ and Bi 3+ , avoiding the co-precipitation of AsSbO4, BiSbO4 and BiSbO7, and obtaining an arsenic-rich solution with an arsenic content of;

[0012] 5) Cooling and crystallization: the arsenic-rich solution obtained in step 4) is naturally cooled and filtered to obtain white arsenic crystals and a crystallized solution; the crystallized solution is returned to step 1).

[0013] The mechanism of the present invention is briefly described as follows:

[0014] The lead copper matte oxygen pressure leaching solution is rich in Cu 2+ , a large amount of S needs to be added 2- Arsenic sulfide slag can provide enough S 2- To precipitate Cu 2+ , Cu 2+ The sulfur-arsenic bond can be broken, so that the arsenic in the filtrate is converted into arsenic acid; the S 2- Arsenic acid is further reduced to arsenous acid, which is unstable in aqueous solution and easily decomposes into arsenic oxide crystals; Na2SO3 is added to further reduce the remaining arsenic acid to arsenous acid, and the Sb in the solution is 5+ 、Bi 5+ Restore to Sb 3+ and Bi 3 + , to avoid the co-precipitation of AsSbO4, BiSbO4 and BiSbO7, 3+ 、Bi 3+Retained in the solution; after natural cooling, the HAsO2 in the arsenic-rich solution after sodium sulfite reduction decomposes to produce arsenic oxide crystals, while impurity elements such as Sb, Bi and Re remain in the solution, achieving effective separation of arsenic and impurities and improving the purity of white arsenic.

[0015] The chemical reaction equation involved in the present invention is mainly:

[0016] As2S3+3CuSO4+4H2O=2HAsO2+3CuS↓+3H2SO4 (1)

[0017] 3H3AsO4+As2S3=5HAsO2+3S↓+2H2O (2)

[0018] H3AsO4+Na2SO3=HAsO2+Na2SO4+H2O (3)

[0019] 2HAsO2=As2O3↓+H2O (4)

[0020] Compared with the prior art, the advantages of the present invention are:

[0021] 1) The present invention uses arsenic sulfide slag to synergistically treat lead matte. The arsenic sulfide slag and lead matte cooperate with each other, copper arsenic is effectively recovered, and the generated white arsenic meets the electronic grade requirements. At the same time, trace amounts of valuable metals such as antimony, bismuth, and rhenium are efficiently enriched in the post-crystallization liquid, and the entire process achieves comprehensive resource recovery.

[0022] 2) The present invention utilizes the arsenic sulfide slag and lead matte produced by the enterprise for coordinated treatment, effectively consuming the hazardous solid waste slag generated in the production process. The reduced slag obtained after treatment can be used in the copper precipitation process together with the arsenic sulfide slag, and the liquid after crystallization can be used as a leaching solvent to return to the lead matte oxygen pressure leaching process for recycling. This process achieves the goals of waste treatment, slag-free, resource utilization and sustainable development;

[0023] 3) The present invention is simple and efficient to operate, has low raw material cost, low production energy consumption, has strong practicality and significant economic benefits, and meets the requirements of green industrial development. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0025] The following is intended to further illustrate the content of the present invention in combination with the drawings and specific preferred embodiments. It should be clearly pointed out that the protection scope of the present invention is not limited to the following specific embodiments.

[0026] The lead matte used in the embodiment of the present invention is a by-product of lead smelting by pyrometallurgy and arsenic sulfide slag produced by the copper smelting electrolysis process. The specific composition is shown in Table 1 and Table 2.

[0027] Table 1 Lead matte composition (wt.%)

[0028]

[0029] Table 2 Composition of arsenic sulfide slag (wt. %)

[0030]

[0031] Embodiment 1:

[0032] A resource recovery method for co-processing lead matte with arsenic sulfide slag, the process flow chart of which is as follows: Figure 1 As shown, the following steps are included:

[0033] 1) Oxygen pressure leaching of lead matte: Weigh an appropriate amount of dried, crushed, ground and sieved lead matte and add it to a pre-prepared sulfuric acid solution. Then transfer the mixture to an autoclave and introduce oxygen for oxygen pressure leaching. The leaching conditions are: initial sulfuric acid concentration of 180 g / L, temperature of 140 °C, oxygen partial pressure of 0.5 MPa, time of 4 h, liquid-to-solid ratio of 7:1, and obtain a leachate with a copper leaching rate of 99.89%;

[0034] 2) Copper precipitation with arsenic sulfide slag: The leaching solution obtained in step 1) was added with arsenic sulfide slag at a copper-arsenic ratio of 1.5:1 according to the copper content therein. The reaction conditions for copper sulfide precipitation were: temperature 95 °C, solution acidity 65 g / L, stirring speed 300 r / min, and time 2 h. The reaction obtained arsenic-containing filtrate and copper sulfide. The results showed that the arsenic-containing filtrate mainly included the following components: As: 28.46 g / L, As 3+ : 21.23 g / L, Cu: 8.14 g / L, H2SO4: 88.02 g / L; The copper sulfide slag contains Cu: 55.73%, S:32.99%, As: 1.43%, and the precipitation rate of Cu reaches 96.96%;

[0035] 3) Arsenic sulfide slag reduction: The arsenic-containing filtrate obtained in step 2) was added with arsenic sulfide slag at a sulfur-arsenic ratio of 1.5:1 according to the arsenic content therein; the reaction conditions were: temperature 95 °C, stirring speed 300 r / min, and time 2 h; after the reaction, reduction slag mainly composed of copper sulfide and arsenous acid solution were obtained; the analysis results showed that the main components of the arsenous acid solution were: As: 33.51 g / L, As 3+: 30.85 g / L, Cu: 5.17 g / L, H2SO4: 99.5 g / L; the reduced slag contains As: 16.32%, Cu: 15.55%, S: 35.42%, return to step 2), and reduce the copper together with the arsenic sulfide slag;

[0036] 4) Sodium sulfite reduction: Add sodium sulfite to the arsenic acid solution obtained in step 3) to reduce the Sb 5+ 、Bi 5 + Restore to Sb 3+ and Bi 3+ , avoiding the co-precipitation of AsSbO4, BiSbO4 and BiSbO7, and obtaining arsenic-rich solution;

[0037] 5) Cooling and crystallization: the arsenic-rich solution obtained in step 4) is naturally cooled and filtered to obtain white arsenic crystals and a crystallized solution; the white arsenic crystals contain As: 75.56%, Cu: 0.0034%, Sb: 0.0042%, Bi: 0.0040%, Re: 0.002%, and the purity of As2O3 is 99.73%, which is suitable for the requirements of electronic grade white arsenic; the crystallized solution is returned to step 1).

[0038] Embodiment 2:

[0039] A resource recovery method for co-processing lead matte with arsenic sulfide slag, the process flow chart of which is as follows: Figure 1 As shown, the following steps are included:

[0040] 1) Oxygen pressure leaching of lead matte: Weigh an appropriate amount of dried, crushed, ground and sieved lead matte and add it to a pre-prepared sulfuric acid solution. Then transfer the mixture to an autoclave and introduce oxygen for oxygen pressure leaching. The leaching conditions are: initial sulfuric acid concentration of 180 g / L, temperature of 130 °C, oxygen partial pressure of 0.6 MPa, time of 4 h, liquid-to-solid ratio of 8:1, and obtain a leachate with a copper leaching rate of 99.69%;

[0041] 2) Copper precipitation with arsenic sulfide slag: The leaching solution obtained in step 1) was added with arsenic sulfide slag at a copper-arsenic ratio of 1.7:1 according to the copper content therein. The reaction conditions for copper sulfide precipitation were: temperature 95 °C, solution acidity 67 g / L, stirring speed 300 r / min, and time 2 h. The reaction obtained arsenic-containing filtrate and copper sulfide. The results showed that the arsenic-containing filtrate mainly included the following components: As: 26.25 g / L, As 3+ : 20.14 g / L, Cu: 7.55 g / L, H2SO4: 89.23 g / L; The copper sulfide slag contains Cu: 54.45%, S: 32.33%, As: 1.56%, and the precipitation rate of Cu reaches 96.77%;

[0042] 3) Arsenic sulfide slag reduction: The arsenic-containing filtrate obtained in step 2) was added with arsenic sulfide slag at a sulfur-arsenic ratio of 1.6:1 according to the arsenic content therein; the reaction conditions were: temperature 95 °C, stirring speed 300 r / min, and time 2 h; after the reaction, reduction slag mainly composed of copper sulfide and arsenous acid solution were obtained; the analysis results showed that the main components of the arsenous acid solution were: As: 31.46 g / L, As 3+ : 28.97 g / L, Cu: 4.67 g / L, H2SO4: 100.5 g / L; the reduced slag contains As: 17.41%, Cu: 14.34%, S: 37.02%, return to step 2), and reduce the copper together with the arsenic sulfide slag;

[0043] 4) Sodium sulfite reduction: Add sodium sulfite to the arsenic acid solution obtained in step 3) to reduce the Sb 5+ 、Bi 5 + Restore to Sb 3+ and Bi 3+ , avoiding the co-precipitation of AsSbO4, BiSbO4 and BiSbO7, and obtaining arsenic-rich solution;

[0044] 5) Cooling and crystallization: the arsenic-rich solution obtained in step 4) is naturally cooled and filtered to obtain white arsenic crystals and a crystallized solution; the white arsenic crystals contain As: 75.48%, Cu: 0.0035%, Sb: 0.0042%, Bi: 0.0044%, Re: 0.0027%, and the purity of As2O3 is 99.63%, which is suitable for the requirements of electronic grade white arsenic; the crystallized solution is returned to step 1).

[0045] Embodiment 3:

[0046] A resource recovery method for co-processing lead matte with arsenic sulfide slag, the process flow chart of which is as follows: Figure 1 As shown, the following steps are included:

[0047] 1) Oxygen pressure leaching of lead matte: Weigh an appropriate amount of dried, crushed, ground and sieved lead matte and add it to a pre-prepared sulfuric acid solution. Then transfer the mixture to an autoclave and introduce oxygen for oxygen pressure leaching. The leaching conditions are: initial sulfuric acid concentration of 170 g / L, temperature of 140 °C, oxygen partial pressure of 0.5 MPa, time of 4 h, liquid-to-solid ratio of 7:1, and obtain a leachate with a copper leaching rate of 99.55%;

[0048] 2) Copper precipitation with arsenic sulfide slag: The leaching solution obtained in step 1) was added with arsenic sulfide slag at a copper-arsenic ratio of 1.7:1 according to the copper content therein. The reaction conditions for copper sulfide precipitation were: temperature 95 °C, solution acidity 59 g / L, stirring speed 300 r / min, and time 3 h. The reaction obtained arsenic-containing filtrate and copper sulfide. The results showed that the arsenic-containing filtrate mainly included the following components: As: 24.63 g / L, As 3+ : 18.77 g / L, Cu: 9.56 g / L, H2SO4: 98 g / L; The copper sulfide slag contains Cu: 55.73%, S:32.99%, As: 1.43%, and the precipitation rate of Cu reaches 96.82%;

[0049] 3) Arsenic sulfide slag reduction: The arsenic-containing filtrate obtained in step 2) was added with arsenic sulfide slag at a sulfur-arsenic ratio of 1.6:1 according to the arsenic content therein; the reaction conditions were: temperature 95 °C, stirring speed 400 r / min, and time 3 h; after the reaction, reduction slag mainly composed of copper sulfide and arsenous acid solution were obtained; the analysis results showed that the main components of the arsenous acid solution were: As: 30.13 g / L, As 3+ : 27.88 g / L, Cu: 7.10 g / L, H2SO4: 96.6 g / L; the reduced slag contains As: 14.78%, Cu: 13.45%, S: 33.46%, return to step 2), and reduce the copper together with the arsenic sulfide slag;

[0050] 4) Sodium sulfite reduction: Add sodium sulfite to the arsenic acid solution obtained in step 3) to reduce the Sb 5+ 、Bi 5 + Restore to Sb 3+ and Bi 3+ , avoiding the co-precipitation of AsSbO4, BiSbO4 and BiSbO7, and obtaining arsenic-rich solution;

[0051] 5) Cooling and crystallization: the arsenic-rich solution obtained in step 4) is naturally cooled and filtered to obtain white arsenic crystals and a crystallized solution; the white arsenic crystals contain As: 75.41%, Cu: 0.0043%, Sb: 0.0044%, Bi: 0.0057%, Re: 0.0031%, and the purity of As2O3 is 99.54%, which is suitable for the requirements of electronic grade white arsenic; the crystallized solution is returned to step 1).

[0052] Finally, it should be pointed out that the above embodiments are only used to illustrate the technical solution of the present invention, and do not limit it. Those skilled in the art should understand that several improvements can be made without departing from the principle of the present invention, but these improvements should also be regarded as the protection scope of the present invention.

Claims

1. A resource recovery method for the coordinated treatment of lead matte with arsenic sulfide slag, It is characterized in that The specific steps include: 1) Lead matte oxygen pressure leaching: the lead matte is dried, crushed and ground, and then passed through a 120-mesh sieve for standby use. An appropriate amount of lead matte powder is added to a pre-prepared sulfuric acid solution, and then the mixture is poured into an autoclave, and oxygen is introduced for oxygen pressure leaching to obtain a copper-containing leaching solution and a lead-containing leaching slag; the lead-containing leaching slag is returned to the lead smelting system; 2) Copper precipitation with arsenic sulfide slag: the copper-containing leaching solution obtained in step 1) is added with arsenic sulfide slag at a certain copper-arsenic ratio according to the copper content therein, and the reaction obtains arsenic-containing filtrate and copper sulfide slag; the copper sulfide slag is returned to the copper smelting system; 3) Arsenic sulfide slag reduction: The arsenic-containing filtrate obtained in step 2) is added with arsenic sulfide waste slag according to the arsenic content in the filtrate and a certain sulfur-arsenic ratio is used to reduce the arsenic sulfide slag. 2- The reducing property of the arsenic acid is used to reduce the arsenic acid to arsenous acid, and the residual copper in step 2) is further precipitated. After the reaction is completed, a reduction slag mainly composed of copper sulfide and an arsenous acid solution are obtained; the reduction slag can be returned to step 2) to reduce the copper together with the arsenic sulfide slag; 4) Sodium sulfite reduction: Add sodium sulfite to the arsenic acid solution obtained in step 3) to reduce the Sb 5+ 、Bi 5+ Restore to Sb 3+ and Bi 3+ , to avoid the formation of AsSbO 4 、BiSbO 4 and BiSbO 7 co-precipitation to obtain arsenic-rich solution; 5) Cooling and crystallization: the arsenic-rich solution obtained in step 4) is naturally cooled and filtered to obtain white arsenic crystals and a crystallized solution; the crystallized solution is returned to step 1).

2. The method according to claim 1, It is characterized in that Step 1) The lead matte is a byproduct produced during the pyrometallurgical lead smelting process and contains valuable elements such as copper, lead, and arsenic. The lead matte includes the following main components by mass percentage: Cu: 20-50%, Pb: 5-20%, As: 5-15%, Sb: 1-5%; the arsenic sulfide slag is produced in the copper electrolysis process of the copper smelting system and contains mainly As. 2 S 3 The smoke dust of the arsenic sulfide slag includes the following main components according to the mass percentage: As: 10%~55%, S: 15%~45%.

3. The method according to claim 1, It is characterized in that Step 1) Lead matte oxygen pressure leaching The reaction is carried out under the conditions of an initial sulfuric acid concentration of 120 to 200 g / L, a temperature of 120 to 180°C, an oxygen partial pressure of 0.3 to 0.8 MPa, a time of 1 to 5 h, and a liquid-to-solid ratio of 4:1 to 9:

1.

4. The method according to claim 1, It is characterized in that In step 2), arsenic sulfide slag is added at a copper-arsenic ratio of 1:1 to 2:1; the sulfidation reaction is carried out at a temperature of 55 to 95°C, a stirring speed of 200 to 500 r / min, a time of 1 to 3 hours, and a solution acidity of 30 to 120 g / L.

5. The method according to claim 1, It is characterized in that In step 3), arsenic sulfide slag is added at a sulfur-arsenic ratio of 0.5:1 to 2.5:1; the reduction reaction is carried out at a temperature of 55 to 95°C, a stirring speed of 200 to 500 r / min, and a time of 1 to 3 h.

6. The method according to claim 1, It is characterized in that In step 4), the sodium sulfite reduction reaction is carried out at a theoretical value multiple (excess coefficient) of sodium sulfite of 0.5:1 to 2.5:1, a temperature of 25 to 80°C, a stirring speed of 200 to 500 r / min, and a time of 1 to 3 h.

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