A method for recovering acid and copper arsenic nickel from arsenic-reduced solution

Abstract

The present application belongs to the technical field of industrial wastewater treatment, and specifically discloses a method for recovering acid and copper-arsenic-nickel from arsenic-reduced liquid by controlling potential. The method comprises the following steps: first, carrying out one-stage diffusion dialysis deacidification on the arsenic-reduced liquid by using a dialysis tank; then, adding a first sulfidizing agent into the diffusion residual liquid to carry out two-stage sulfidization for removing copper and arsenic; then, adding a second sulfidizing agent into the two-stage sulfidized liquid to carry out three-stage sulfidization for removing arsenic; finally, adding an alkaline neutralizing agent into the three-stage sulfidized liquid to carry out four-stage neutralization for precipitating nickel, so as to obtain neutralized slag containing nickel. The method is simple in operation and easy to be industrialized, and can recover more than 90% of copper, arsenic and nickel in the arsenic-reduced liquid, and provide qualified raw materials for high-quality nickel-containing products. The method realizes efficient recovery of copper, arsenic and nickel, has important economic, environmental and social benefits, and does not produce new wastewater, thereby reducing environmental pollution, being safe and environmentally friendly, and being conducive to wastewater reuse and subsequent treatment.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of industrial wastewater treatment, and particularly relates to a method for recovering acid, copper, arsenic and nickel from arsenic-reduced liquid by controlling electric potential. BACKGROUND

[0002] Currently, liquid SO2 reduction or smelting and purification flue gas reduction is generally used in the existing wet process for producing arsenic trioxide, and the reduced liquid contains a large amount of acid and copper. With the increase of copper smelting treatment capacity, various copper, arsenic and nickel-containing materials enter the wet arsenic production system. If the acid and valuable elements in the arsenic-reduced liquid are not recovered, a large amount of resources will be wasted. Therefore, the acid and valuable elements in the arsenic-reduced liquid must be recovered.

[0003] The existing arsenic-reduced liquid treatment process adopts the treatment method of flocculation, neutralization and precipitation, which not only produces a large amount of neutralization slag, but also causes the loss of valuable components such as copper, nickel and sulfuric acid. Moreover, it can only treat low-concentration arsenic-containing wastewater, and even if chelating resin adsorption is used, the pH needs to be adjusted to neutral. Due to the low nickel grade and the presence of copper and arsenic impurities in the nickel-containing material, the nickel product extraction process is long, the alkali consumption is large, the process is complex, and the direct recovery rate and recovery rate of nickel are greatly reduced.

[0004] For the treatment of arsenic-reduced liquid, the existing technology mainly has the following technical problems:

[0005] (1) High acid cannot be reused and recycled, and the neutralization cost is high;

[0006] (2) The nickel product contains copper and arsenic, and the quality is low, which is not conducive to refining;

[0007] (3) Copper and arsenic cannot be separated in stages, which is not conducive to reuse.

[0008] Therefore, we propose a method for recovering acid, copper, arsenic and nickel from arsenic-reduced liquid by controlling electric potential to solve the above problems, which can realize the recycling of valuable metals and inorganic acid in the arsenic-reduced liquid, and has important economic, environmental and social benefits. SUMMARY

[0009] The purpose of the present application is to provide a method for recovering acid, copper, arsenic and nickel from arsenic-reduced liquid by controlling electric potential, which is simple in operation and easy to industrialize. More than 90% of copper, arsenic and nickel in the arsenic-reduced liquid can be recovered, and qualified raw materials for high-quality nickel-containing products can be provided. The efficient recovery of copper, arsenic and nickel is realized, which has important economic, environmental and social benefits, to solve the problems raised in the above background technology.

[0010] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0011] A method for recovering acid and copper-arsenic-nickel from arsenic-reduced solution by controlling potential, comprising the following steps:

[0012] S1, performing deacidification treatment on the arsenic-reduced solution by one-stage diffusion dialysis through a dialysis tank, so that the acidity value of the diffusion residual liquid in the dialysis tank is reduced to 80 g / L, and diffusion residual liquid and recovered acid are obtained;

[0013] S2, collecting the recovered acid and using it as arsenic filter cake slurry supplement acid for recovery;

[0014] S3, adding a first sulfidizing agent to the diffusion residual liquid to perform a first sulfidation reaction, and filtering the first sulfidation reaction liquid to obtain a second sulfidation post-liquid and a second sulfidation residue containing copper and arsenic;

[0015] S4, smelting and processing the second sulfidation residue for recovery;

[0016] S5, adding a second sulfidizing agent to the second sulfidation post-liquid to perform a second sulfidation reaction, and filtering the second sulfidation reaction liquid to obtain a third sulfidation post-liquid and a third sulfidation residue containing arsenic;

[0017] S6, collecting the third sulfidation residue and processing it for arsenic recovery;

[0018] S7, adding an alkaline neutralizing agent to the third sulfidation post-liquid to perform a neutralization reaction, so that the pH value of the neutralization reaction liquid is 7.5-10.5, and then filtering the neutralization reaction liquid to obtain a neutralization residue containing nickel.

[0019] Preferably, the dialysis tank in step S1 comprises a tank body, the inside of the tank body is composed of three equally spaced tank cavities through two dialysis plates, the three tank cavities are a dialysis cavity and two recovery cavities respectively, the two recovery cavities are located on both sides of the dialysis cavity, one side of the two recovery cavities is communicated with a liquid transmission mechanism, and one side of the dialysis cavity is communicated with a liquid inlet pipe and a liquid outlet pipe.

[0020] Preferably, the bottom of the dialysis cavity and the bottom of the two recovery cavities form a convex structure, and the liquid inlet pipe and the liquid outlet pipe are located on the same horizontal plane.

[0021] Preferably, the liquid transmission mechanism comprises a main water pipe and a branch water pipe, the main water pipe and the branch water pipe are vertically arranged, the two ends of the branch water pipe are respectively communicated with the two recovery cavities, and water valves are installed on the main water pipe, the liquid inlet pipe and the liquid outlet pipe.

[0022] Preferably, the dialysis plate comprises a mouth-shaped fixed frame and a semi-permeable membrane installed on the inner side of the fixed frame, and the outer wall of the fixed frame is fixed with the inner wall of the tank body.

[0023] Preferably, in step S2, when the recovered acid is used, the acid is first volatilized into steam by heating the recovered acid, then the acid liquid is obtained by condensation, and then the acid liquid is filtered to remove impurities in the acid liquid, and the acid liquid is used as a supplement acid, while the metal salt is left in the mother liquor of the recovered acid.

[0024] Preferably, in step S3, the primary vulcanizing agent is solid sodium thiosulfate or liquid sodium thiosulfate, and the diffusion residual liquid needs to be stirred during the primary vulcanization reaction, and the reaction conditions of the primary vulcanization reaction are as follows: the reaction temperature is 50-100 DEG C, the reaction time is 30-180 min, the stirring speed is 100-600 r / min, and the reaction endpoint potential is 200-300 mv.

[0025] Preferably, in step S5, the secondary vulcanizing agent is one or more of sodium sulfide, sodium hydrosulfide and hydrogen sulfide, and stirring is needed during the secondary vulcanization reaction, and the reaction conditions of the secondary vulcanization reaction are as follows: the reaction temperature is 20-80 DEG C, the reaction time is 30-240 min, the stirring speed is 100-600 r / min, and the reaction endpoint potential is 50-180 mv.

[0026] Preferably, in step S6, when the three-stage vulcanization residue is processed for arsenic recovery, the arsenic in the arsenic-containing waste residue is leached by a chemical method, and the arsenic is oxidized to pentavalent arsenic, and the pentavalent arsenic is crystallized and solidified under hydrothermal conditions or under atmospheric pressure heating conditions.

[0027] Preferably, in step S7, the alkaline neutralizing agent is one or more of sodium hydroxide, calcium hydroxide and potassium hydroxide, and the three-stage vulcanized liquid needs to be stirred during the neutralization reaction, and the reaction conditions of the neutralization reaction are as follows: the reaction temperature is 30-90 DEG C, the reaction time is 60-180 min, the stirring speed is 100-600 r / min, and the neutralized liquid after filtration is treated in a wastewater treatment system.

[0028] The method for recovering acid and copper, arsenic and nickel from arsenic-reduced liquid by controlling potential provided by the application has the following advantages compared with the prior art:

[0029] 1. The method provided by the application has the advantages of simple operation, easy industrialization, recovery of more than 90% of copper, arsenic and nickel from arsenic-reduced liquid, provision of qualified raw materials for high-quality nickel-containing products, high-efficiency recovery of copper, arsenic and nickel, and important economic, environmental and social benefits.

[0030] 2. The method provided by the application does not produce new wastewater, reduces environmental pollution, is safe and environmentally friendly, and is conducive to wastewater reuse and subsequent treatment. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 Flow chart of the present application;

[0032] Figure 2 Schematic diagram of the present application;

[0033] Figure 3 Schematic diagram of the present application;

[0034] In the figure: 1, tank body; 2, dialysis cavity; 3, recovery cavity; 4, water supply pipe; 5, main water pipe; 6, liquid inlet pipe; 7, liquid outlet pipe; 8, dialysis plate; 81, fixed frame; 82, semi-permeable membrane. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. The specific embodiments described herein are only used to explain the present application, and are not used to limit the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application. Embodiment 1

[0036] The present application provides a method for recovering acid and copper arsenic nickel from arsenic-reduced solution, as shown in Figures 1-3 The method comprises the following steps:

[0037] S1, performing one-stage diffusion dialysis on the arsenic-reduced solution by a dialysis tank to perform deacidification treatment, so that the acidity value of the diffusion residual solution in the dialysis tank is reduced to 80 g / L, and diffusion residual solution and recovered acid are obtained;

[0038] The dialysis tank comprises a tank body 1, the inside of the tank body 1 is composed of three equally spaced tank cavities by two dialysis plates 8, the three tank cavities are a dialysis cavity 2 and two recovery cavities 3 respectively, the two recovery cavities 3 are located on the two sides of the dialysis cavity 2 respectively, one side of the two recovery cavities 3 is communicated with a liquid transmission mechanism, and one side of the dialysis cavity 2 is communicated with a liquid inlet pipe 6 and a liquid outlet pipe 7.

[0039] During dialysis, the arsenic-reduced solution is added into the dialysis cavity 2 through the liquid inlet pipe 6, ion water or pure water is added into the recovery cavity 3, liquid concentration differences are generated between the dialysis cavity 2 and the recovery cavities 3 on both sides, dialysis is simultaneously performed from both sides of the dialysis tank, the dialysis rate of the liquid in the dialysis cavity 2 can be effectively increased, the dialysis plates 8 on both sides of the dialysis cavity 2 are used to dialyze the arsenic-reduced solution, the arsenic-reduced solution in the dialysis cavity 2 is deacidified, and the liquid in the dialysis cavity 2 after deacidification is the diffusion residual solution, and the liquid in the recovery cavity 3 is the recovered acid.

[0040] The bottom of the dialysis cavity 2 and the bottom of the two recovery cavities 3 form a convex structure, which facilitates the diffusion of the liquid in the dialysis cavity 2 into the recovery cavity 3, improves the dialysis efficiency of the arsenic-reduced liquid, and the liquid inlet pipe 6 and the liquid outlet pipe 7 are located on the same horizontal plane, which facilitates the addition or discharge of the arsenic-reduced liquid in the dialysis cavity 2.

[0041] The liquid transmission mechanism includes a main water pipe 5 and a branch water pipe 4, the main water pipe 5 and the branch water pipe 4 are vertically arranged, and the two ends of the branch water pipe 4 are respectively communicated with the two recovery cavities 3, and water valves are installed on the main water pipe 5, the liquid inlet pipe 6 and the liquid outlet pipe 7, which facilitates the control of the on-off of the liquid inlet pipe 6, the liquid outlet pipe 7 and the main water pipe 5, and the branch water pipe 4 facilitates the collection of the recovered acid in the two recovery tanks to the main water pipe 5, and then discharged through the main water pipe 5, improving the convenience of the transmission of the recovered acid.

[0042] The dialysis plate 8 includes a fixed frame 81 in the shape of a mouth and a semi-permeable membrane 82 installed on the inner side of the fixed frame 81, and the outer wall of the fixed frame 81 is fixed with the inner wall of the tank body 1, and the semi-permeable membrane 82 is supported and fixed by the fixed frame 81, and the semi-permeable membrane 82 is a kind of thin film with selective permeability made of cell membrane, sheepskin paper and artificial cotton film, which can allow some molecules and ions to pass through, while preventing other macromolecules or particles of a certain size from passing through. In the dialysis process, the semi-permeable membrane 82 is used to separate different solute particles such as ions in the solution.

[0043] S2, collect the recovered acid and use it as arsenic filter cake slurry supplement acid for recovery;

[0044] When the recovered acid is used for recovery, the recovered acid is first heated to volatilize into steam, then condensed to obtain acid liquid, and then filtered to remove impurities in the acid liquid, and the acid liquid is used as a supplement acid, while the metal salt is left in the mother liquor of the recovered acid.

[0045] S3, adding a sulfurizing agent to the diffusion residual liquid to perform a first sulfurization reaction, and filtering the first sulfurization reaction liquid to obtain a second sulfurization liquid and a second sulfurization residue containing copper and arsenic;

[0046] The first sulfurizing agent is set as solid sodium thiosulfate or liquid sodium thiosulfate, and the diffusion residual liquid needs to be stirred during the first sulfurization reaction. The reaction conditions of the first sulfurization reaction are as follows: reaction temperature 50-100℃, reaction time 30-180min, stirring speed 100-600r / min, and reaction end potential 200-300mv. The recovery rate of copper in the treated diffusion residual liquid is greater than 90%.

[0047] S4, smelting and processing the second sulfurization residue for recovery; the steps of smelting and processing recovery are as follows:

[0048] Chloride leaching: By using chloride salts, copper and other valuable metals such as bismuth, antimony, silver, etc. can be separated from solid waste through leaching treatment.

[0049] Stepwise hydrolysis: After the leaching process, further processing is carried out through stepwise hydrolysis technology to improve the recovery rate of valuable metals.

[0050] Low-temperature blowing: Using low-temperature blowing technology, copper and other valuable metals can be effectively recovered from arsenic-removed slag.

[0051] Selective arsenic removal: Research on high-selectivity arsenic capture agents, through selective arsenic removal process, reduce the leaching toxicity of arsenic, realize the safe disposal of arsenic.

[0052] S5, adding a secondary sulfidation agent to the two-stage sulfidation liquid to carry out a secondary sulfidation reaction, and filtering the secondary sulfidation reaction liquid to obtain a three-stage sulfidation liquid and a three-stage sulfidation slag containing arsenic;

[0053] The secondary sulfidation agent is set as one or more of sodium sulfide, sodium hydrosulfide, and hydrogen sulfide. Stirring is required during the secondary sulfidation reaction. The reaction conditions for the secondary sulfidation reaction are: reaction temperature 20-80℃, reaction time 30-240min, stirring speed 100-600r / min, and reaction endpoint potential 50-180mv.

[0054] S6, collecting the three-stage sulfidation slag and carrying out arsenic recovery processing;

[0055] When the three-stage sulfidation slag is subjected to arsenic recovery processing, arsenic in the arsenic-containing waste slag is first leached out by a chemical method, and then oxidized to pentavalent arsenic. The pentavalent arsenic is subjected to crystallization and solidification treatment under hydrothermal conditions or under normal pressure heating conditions.

[0056] The steps for crystallization and solidification treatment of pentavalent arsenic are as follows:

[0057] Dissolution: Mix the waste slag containing pentavalent arsenic with water, adjust the pH value of the solution to the acidic range (usually between 2-6), to promote the dissolution of pentavalent arsenic.

[0058] Filtration: Remove the insoluble substances in the waste slag by filtration or centrifugation, etc. to obtain a solution containing pentavalent arsenic.

[0059] Crystallization: Heat the solution containing pentavalent arsenic to boiling, then gradually cool it down, so that pentavalent arsenic precipitates in solid form. The crystallization process can be adjusted by controlling parameters such as cooling speed and stirring speed, to obtain crystals of different shapes and sizes.

[0060] Separation and washing: Separate the precipitated pentavalent arsenic crystals from the mother liquor, then wash them with water or other suitable solvents to remove surface impurities and residual solvents.

[0061] Drying: The washed pentavalent arsenic crystals are dried under appropriate conditions to remove moisture and other volatile substances, resulting in pure pentavalent arsenic crystals.

[0062] Packaging and storage: The dried pentavalent arsenic crystals are packaged and sealed to prevent moisture absorption and oxidation, and stored in a cool, dry place.

[0063] S7, adding an alkaline neutralizing agent to the three-stage sulfurized liquid for neutralization reaction, so that the pH value of the neutralization reaction liquid is 7.5-10.5, and then filtering the neutralization reaction liquid to obtain a neutralization residue containing nickel;

[0064] The alkaline neutralizing agent is set as one or more of sodium hydroxide, calcium hydroxide and potassium hydroxide. The three-stage sulfurized liquid is stirred during the neutralization reaction. The reaction conditions for the neutralization reaction are: reaction temperature 30-90℃, reaction time 60-180min, stirring speed 100-600r / min. After reaction, the neutralization liquid is filtered and treated in a wastewater treatment system. Example 2

[0065] According to the method provided in Example 1, the arsenic reduction liquid is subjected to first actual acid and copper-arsenic-nickel recovery, and the recovery process is as follows:

[0066] 1. The composition of copper (Cu), arsenic (As) and nickel (Ni) in the arsenic reduction liquid is determined, and the results are shown in the following table:

[0067] Element class Cu As Ni H2SO4 Content (g / L) 41.33 23.09 4.06 185.7

[0068] 2. The recovered acid and diffusion residual liquid are obtained by membrane diffusion dialysis, and the composition of the diffusion residual liquid is determined as shown in the following table:

[0069] Element class Cu As Ni H2SO4 Content (g / L) 33.46 17.43 3.01 76.4

[0070] The recovered acid can be reused as arsenic filter cake slurry supplement acid, and the diffusion residual liquid enters the next process.

[0071] 3. A certain proportion of sodium thiosulfate solid is added to the diffusion residual liquid, the reaction temperature is 50℃, the reaction time is 180min, the stirring speed is 400r / min, and the reaction endpoint potential is 300mv. After filtration and washing, a two-stage sulfurization residue containing copper and arsenic and a two-stage sulfurization liquid are obtained, and the composition of the two-stage sulfurization liquid is shown in the following table:

[0072] Element class Cu As Ni Content (g / L) 0.74 14.16 2.92

[0073] The recovery rate of the second-stage sulfurized copper is 97.8%, which is greater than 90%. The second-stage sulfurized residue can be used as high-quality copper-containing material into the smelting production system, and the second-stage sulfurized liquid enters the next process.

[0074] 4. A certain proportion of sodium sulfide is added to the second-stage sulfurized liquid, the reaction temperature is 20°C, the reaction time is 240 min, the stirring speed is 400 r / min, the reaction end potential is 180 mv, and after filtration and washing, the third-stage sulfurized residue and the third-stage sulfurized liquid are obtained. The composition of the third-stage sulfurized liquid is shown in the following table:

[0075] Element class Cu As Ni Content (g / L) 0.013 0.67 2.78

[0076] The recovery rate of the third-stage sulfurized arsenic is 95.3%, which is greater than 90%. The third-stage sulfurized residue can be used as high-quality raw material into the arsenic recovery process, and the third-stage sulfurized liquid enters the next process.

[0077] 5. A certain proportion of sodium hydroxide is added to the third-stage sulfurized liquid, the reaction temperature is 30°C, the reaction time is 180 min, the stirring speed is 400 r / min, the reaction end pH is 7.5, and after filtration and washing, the neutralized residue and the neutralized liquid are obtained. The composition of the neutralized liquid is shown in the following table:

[0078] Element class Cu As Ni Content (g / L) 0.008 0.31 0.045

[0079] The recovery rate of the fourth-stage neutralized nickel is 98.4%, which is greater than 90%. The neutralized residue can be used as high-quality nickel raw material for export, and the neutralized liquid enters the wastewater treatment process.

[0080] In the whole process, the recovery rate of the second-stage copper is 97.8%, the recovery rate of the third-stage arsenic is 95.3%, and the recovery rate of the fourth-stage nickel is 98.4%. Moreover, the valuable metals can be extracted in a step-by-step manner, which has good selectivity and solves the dispersion problem in the process of re-separation and extraction of valuable metals. In addition, most of the inorganic acid is recycled, which effectively reduces the production cost and wastewater treatment cost. Example 3

[0081] According to the method provided in Example 1, the arsenic-reduced liquid is subjected to a second actual acid recovery and copper-arsenic-nickel recovery, and the recovery process is as follows:

[0082] 1. The composition of copper (Cu), arsenic (As), and nickel (Ni) in the arsenic-reduced liquid is confirmed, and the confirmation results are shown in the following table:

[0083] Element class Cu As Ni H2SO4 Content (g / L) 40.82 22.45 3.68 180.9

[0084] 2. The recovered acid and the diffusion residual liquid are obtained by membrane diffusion dialysis, and the composition of the diffusion residual liquid is confirmed as shown in the following table:

[0085] Element class Cu As Ni H2SO4 Content (g / L) 32.17 16.89 2.96 73.2

[0086] The recovered acid can be reused as arsenic filter cake slurry supplement acid, and the diffusion residual liquid enters the next process.

[0087] 3. A certain proportion of sodium thiosulfate liquid is added to the diffusion residual liquid, the reaction temperature is 75°C, the reaction time is 120 min, the stirring speed is 300 r / min, the reaction end potential is 250 mv, and after filtration and washing, the second-stage sulfidation residue containing copper and arsenic and the second-stage sulfidation liquid are obtained. The composition of the second-stage sulfidation liquid is shown in the following table:

[0088] Element class Cu As Ni Content (g / L) 0.54 12.77 2.83

[0089] The recovery rate of the second-stage sulfidation copper is 98.3%, which is greater than 90%. The second-stage sulfidation residue can be used as high-quality copper-containing material into the smelting production system, and the second-stage sulfidation liquid enters the next process.

[0090] 4. A certain proportion of sodium hydrosulfide is added to the second-stage sulfidation liquid, the reaction temperature is 50°C, the reaction time is 120 min, the stirring speed is 300 r / min, the reaction end potential is 110 mv, and after filtration and washing, the third-stage sulfidation residue and the third-stage sulfidation liquid are obtained. The composition of the third-stage sulfidation liquid is shown in the following table:

[0091] Element class Cu As Ni Content (g / L) 0.011 0.59 2.66

[0092] The recovery rate of the third-stage sulfidation arsenic is 95.3%, which is greater than 90%. The third-stage sulfidation residue can be used as high-quality raw material to the arsenic recovery process, and the third-stage sulfidation liquid enters the next process.

[0093] 5. A certain proportion of calcium hydroxide is added to the third-stage sulfidation liquid, the reaction temperature is 60°C, the reaction time is 90 min, the stirring speed is 300 r / min, the reaction end pH is 9, and after filtration and washing, the neutralization residue and the neutralization liquid are obtained. The composition of the neutralization liquid is shown in the following table:

[0094] Element class Cu As Ni Content (g / L) 0.007 0.27 0.038

[0095] The recovery rate of the fourth-stage neutralization nickel is 98.5%, which is greater than 90%. The neutralization residue can be used as high-quality nickel raw material for export, and the neutralization liquid enters the wastewater treatment process.

[0096] In the whole process, the recovery rate of the second-stage copper is 98.3%, the recovery rate of the third-stage arsenic is 95.3%, and the recovery rate of the fourth-stage nickel is 98.5%. Moreover, the valuable metals can be extracted in a gradient and segmented manner, with good selectivity, which solves the dispersion problem in the process of re-separation and extraction of valuable metals. Moreover, most of the inorganic acid is reused, which effectively reduces the production cost and wastewater treatment cost. Example 4

[0097] The third actual recovery of acid and copper arsenic nickel was carried out on the arsenic-reduced solution according to the method provided in Embodiment 1, and the recovery process is as follows:

[0098] 1. The components of Cu, As and Ni in the arsenic-reduced solution were confirmed, and the confirmation results are shown in the following table:

[0099] Element class Cu As Ni H2SO4 Content (g / L) 40.15 22.41 3.85 182.2

[0100] 2. The recovered acid and the diffusion residual liquid were obtained by membrane diffusion dialysis, and the component confirmation of the diffusion residual liquid is shown in the following table:

[0101] Element class Cu As Ni H2SO4 Content (g / L) 31.96 16.63 2.99 72.4

[0102] The recovered acid can be reused as an arsenic filter cake slurry supplement acid, and the diffusion residual liquid enters the next process.

[0103] 3. A certain proportion of sodium thiosulfate solid was added to the diffusion residual liquid, the reaction temperature was 100°C, the reaction time was 30 min, the stirring speed was 200 r / min, and the reaction end potential was 200 mv. After filtration and washing, the second-stage sulfidation residue containing copper and arsenic and the second-stage sulfidation solution were obtained, and the components of the second-stage sulfidation solution are shown in the following table:

[0104] Element class Cu As Ni Content (g / L) 0.45 13.87 2.83

[0105] The recovery rate of the second-stage sulfidation copper is 98.6%, which is greater than 90%. The second-stage sulfidation residue can be used as high-quality copper-containing material into the smelting production system, and the second-stage sulfidation solution enters the next process.

[0106] 4. A certain proportion of hydrogen sulfide was added to the second-stage sulfidation solution, the reaction temperature was 80°C, the reaction time was 30 min, the stirring speed was 200 r / min, the reaction end potential was 50 mv, and the third-stage sulfidation residue and the third-stage sulfidation solution were obtained after filtration and washing. The components of the third-stage sulfidation solution are shown in the following table:

[0107] Element class Cu As Ni Content (g / L) 0.007 0.55 2.68

[0108] The recovery rate of the third-stage sulfidation arsenic is 96.1%, which is greater than 90%. The third-stage sulfidation residue can be used as high-quality raw material into the arsenic recovery process, and the third-stage sulfidation solution enters the next process.

[0109] 5. A certain proportion of potassium hydroxide was added to the third-stage sulfidation solution, the reaction temperature was 90°C, the reaction time was 60 min, the stirring speed was 200 r / min, the reaction end pH was 10.5, and the neutralization residue and the neutralization solution were obtained after filtration and washing. The components of the neutralization solution are shown in the following table:

[0110] Element class Cu As Ni Content (g / L) Element class Cu As Ni Content (g / L) Element class Cu As Ni Content (g / L) Element class Cu As Ni Content (g / L) 0.005 0.26 0.035

[0111] The recovery rate of nickel in the fourth stage is 98.7%, which is greater than 90%. The neutralization slag can be sold as high-quality nickel raw material, and the liquid after neutralization enters the wastewater treatment process.

[0112] The recovery rate of copper in the second stage is 98.6%, the recovery rate of arsenic in the third stage is 96.1%, and the recovery rate of nickel in the fourth stage is 98.7%. Moreover, the valuable metals can be extracted in stages, and the selectivity is good, which solves the dispersion problem in the process of re-separation and extraction of valuable metals. Moreover, most of the inorganic acid is recycled, which effectively reduces the production cost and wastewater treatment cost.

[0113] In summary, by using the dialysis tank to perform one-stage diffusion dialysis deacidification on the arsenic-reduced liquid, adding a first sulfidation agent to the diffusion residual liquid to perform two-stage sulfidation to remove copper and arsenic, adding a second sulfidation agent to the two-stage sulfidation liquid to perform three-stage sulfidation to remove arsenic, and finally adding an alkaline neutralizing agent to the three-stage sulfidation liquid to perform four-stage neutralization to precipitate nickel, the neutralization slag containing nickel is obtained. This method is simple to operate and easy to industrialize. More than 90% of copper, arsenic, and nickel in the arsenic-reduced liquid can be recovered, and qualified raw materials for high-quality nickel-containing products are provided. The efficient recovery of copper, arsenic, and nickel is achieved, which has important economic, environmental, and social benefits. Moreover, this method does not produce new wastewater, reduces environmental pollution, is safe and environmentally friendly, and is conducive to wastewater recycling and subsequent treatment.

[0114] Finally, it should be noted that the above description is only a preferred embodiment of the present application and is not intended to limit the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can modify the technical solutions described in the foregoing embodiments or make equivalent replacements to some technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for recovering acid and copper, arsenic, and nickel from arsenic reduction solution under controlled potential, characterized in that: Includes the following steps: S1. The arsenic reduction solution is subjected to a first-stage diffusion dialysis in a dialysis tank to remove acid, thereby reducing the acidity of the diffusion residue in the dialysis tank to 80 g / L, and obtaining the diffusion residue and recovering acid. S2. Collect the recovered acid and use it as supplementary acid for arsenic filter cake slurry production; S3. Add a sulfiding agent to the diffusion residue to carry out a sulfidation reaction, and filter the sulfidation reaction liquid to obtain the second-stage sulfidation liquid and the second-stage sulfidation slag containing copper and arsenic. The primary vulcanizing agent is set as solid sodium thiosulfate or liquid sodium thiosulfate. During the primary vulcanization reaction, the diffusion residue needs to be stirred. The reaction conditions for the primary vulcanization reaction are: reaction temperature 50-100℃, reaction time 30-180min, stirring speed 100-600r / min, and reaction endpoint potential 200-300mv. S4. The second-stage sulfidation slag is smelted, processed, and recycled. S5. Add a secondary sulfiding agent to the liquid after the second stage of sulfidation to carry out a secondary sulfidation reaction, and filter the secondary sulfidation reaction liquid to obtain the liquid after the third stage of sulfidation and the arsenic-containing third stage sulfidation slag. The secondary vulcanizing agent is set as one or more of sodium sulfide, sodium hydrosulfide and hydrogen sulfide. The secondary vulcanization reaction needs to be stirred. The reaction conditions for the secondary vulcanization reaction are: reaction temperature 20-80℃, reaction time 30-240min, stirring speed 100-600r / min, and reaction endpoint potential 50-180mv. S6. Collect the three sections of sulfide slag and process them for arsenic recovery. S7. Add an alkaline neutralizing agent to the liquid after the three-stage sulfidation to carry out a neutralization reaction, so that the pH value of the neutralization reaction liquid is 7.5-10.

5. Then filter the neutralization reaction liquid to obtain neutralization slag containing nickel.

2. The method for recovering acid and copper-arsenic-nickel from arsenic reduction solution by controlling potential according to claim 1, characterized in that: The dialysis tank in step S1 includes a tank body (1). The interior of the tank body (1) is formed by two dialysis plates (8) to form three equally spaced cavities. The three cavities are a dialysis cavity (2) and two recovery cavities (3). The two recovery cavities (3) are located on both sides of the dialysis cavity (2). One side of the two recovery cavities (3) is connected to a liquid transfer mechanism. One side of the dialysis cavity (2) is connected to an inlet pipe (6) and an outlet pipe (7).

3. The method for recovering acid and copper, arsenic, and nickel from arsenic reduction solution by controlling potential according to claim 2, characterized in that: The bottom of the dialysis chamber (2) and the bottom of the two recovery chambers (3) form a convex structure, and the inlet pipe (6) and outlet pipe (7) are located on the same horizontal plane.

4. The method for recovering acid and copper-arsenic-nickel from arsenic reduction solution by controlling potential according to claim 3, characterized in that: The liquid transfer mechanism includes a main water pipe (5) and a branch water pipe (4). The main water pipe (5) and the branch water pipe (4) are arranged vertically, and the two ends of the branch water pipe (4) are respectively connected to two recovery chambers (3). Water valves are installed on the main water pipe (5), the inlet pipe (6) and the outlet pipe (7).

5. The method for recovering acid and copper-arsenic-nickel from arsenic reduction solution by controlling potential according to claim 4, characterized in that: The dialysis plate (8) includes a square-shaped fixing frame (81) and a semi-permeable membrane (82) installed inside the fixing frame (81). The outer wall of the fixing frame (81) is fixed to the inner wall of the tank (1).

6. The method for recovering acid and copper-arsenic-nickel from arsenic reduction solution by controlling potential according to claim 5, characterized in that: In step S2, when the recovered acid is recycled, it is first heated to evaporate the acid into vapor, and then the acid solution is obtained by condensation. The acid solution is then filtered to remove impurities and used as supplementary acid, while the metal salt remains in the mother liquor of the recovered acid.

7. The method for recovering acid and copper-arsenic-nickel from arsenic reduction solution by controlling potential according to claim 6, characterized in that: In step S6, when the three-stage sulfide slag is processed for arsenic recovery, the arsenic in the arsenic-containing waste slag is first leached out by chemical methods and oxidized into pentavalent arsenic. The pentavalent arsenic is then crystallized and solidified under hydrothermal conditions or atmospheric pressure heating conditions.

8. The method for recovering acid and copper-arsenic-nickel from arsenic reduction solution by controlling potential according to claim 7, characterized in that: In step S7, the alkaline neutralizing agent is one or more of sodium hydroxide, calcium hydroxide, and potassium hydroxide. During the neutralization reaction, the three-stage sulfidation liquid needs to be stirred. The reaction conditions for the neutralization reaction are: reaction temperature 30-90℃, reaction time 60-180min, and stirring speed 100-600r / min. The neutralized liquid filtered after the reaction is sent to the wastewater treatment system for treatment.

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