A method for leaching tin from copper electrolyte using oxygen pressure

Abstract

The present invention relates to the technical field of recycled copper smelting, and specifically to a method for tin precipitation from copper electrolyte by oxygen pressure leaching, comprising adding a pH regulator to a copper electrolyte containing copper, tin, and nickel, stirring and adjusting the pH to 0.5 to 6 to obtain a mixed slurry; adding the mixed slurry to a high-pressure reactor for oxygen pressure stirring leaching, and obtaining a solid-liquid mixture after the oxygen pressure stirring leaching reaction; and subjecting the solid-liquid mixture to solid-liquid separation, whereby the filtrate is a purified copper electrolyte solution containing copper and nickel, and the filter residue is a tin precipitation residue. The method of the present invention achieves efficient precipitation and separation of tin from the copper electrolyte, and the resulting tin-containing precipitate has stable crystal properties and excellent liquid-solid separation performance, thereby resolving the technical problem of colloidal tin-containing hydrates in the copper electrolyte causing solution turbidity and difficulty in liquid-solid separation. The method of the present invention does not use any flocculants or precipitants, and does not introduce harmful impurities, which is conducive to the subsequent recycling of the copper electrolyte. It is simple to operate, highly efficient, and has good prospects for promotion and application.

Description

Technical Field

[0001] One or more embodiments of the present specification relate to the technical field of recycled copper smelting, and in particular to a method for tin precipitation by oxygen pressure leaching of copper electrolyte. Background Art

[0002] Currently, nearly one-third of China's copper consumption comes from the recycling of scrap copper, and my country's scrap copper recycling industry has excellent development prospects. Compared with copper concentrate, producing metallic copper from scrap copper offers advantages such as simpler equipment, lower investment, higher recovery rates, lower energy consumption, lower costs, and less pollution. This not only alleviates the scarcity of primary copper resources in my country and supplements the shortage of mineral resources, but also reduces environmental pollution and promotes the sustainable development of copper enterprises.

[0003] Domestic scrap copper primarily consists of discarded copper parts, waste from copper alloy production or machining, copper slag, copper ash, waste wire and cable, and electroplating alloy waste. In particular, the vast quantity of scrap tin-plated copper represents a highly promising renewable resource, offering significant potential for the production of recycled copper and tin. For low-grade scrap copper, such as scrap tin-plated copper wire, tin-plated scrap, and electroplating alloy waste, domestic recycled copper smelting companies generally employ pyrometallurgical smelting. The electrolytic method involves smelting low-grade scrap copper into black copper anodes (80%-85% copper content), which are then electrolyzed to produce cathode copper. Compared to traditional mineral copper smelting processes, this method's notable feature is the tin-rich copper electrolyte, typically with a Sn concentration of 0.5-10 g / L.

[0004] The copper electrolyte containing tin is easy to become turbid, which has always been a difficult technical problem to solve. This is because the waste tin-plated copper material is processed through the process of fire smelting-electrolytic refining, and the tin is converted into Sn. 2+ 、Sn 4+ The Sn in the acidic electrolyte will continue to accumulate and increase. 2+ Easily oxidized to Sn 4+ Furthermore, Sn(OH)4 is hydrolyzed, which readily polymerizes to form β-stannic acid [β-(SnO2.H2O)5]. β-(SnO2.H2O)5 has colloidal properties and remains suspended in the solution, causing the electrolyte to become increasingly turbid. The main impacts of turbid tin-containing electrolytes on the copper electrolysis process include the appearance of numerous particles at the cathode, a significant increase in anode slime, and severe wall buildup during electrolysis, impacting product quality and significantly reducing current efficiency.

[0005] At present, flocculants such as polyacrylamide are generally added to remove tin and other impurities from copper electrolyte. This is a common electrolyte purification process. However, there are problems such as large flocculant consumption, difficulty in filtering the solution, and poor tin removal effect. In addition, the added polyacrylamide will affect the normal progress of the copper electrolysis process along with the recycling of the electrolyte, and will also lead to problems such as the quality of subsequent evaporation crystallization-nickel sulfate and difficulty in separating gold and silver from anode mud. In addition, domestic and foreign researchers have also developed a copper replacement-neutralization precipitation method to separate tin and copper from copper electrolyte; for example, invention patent CN110499521B discloses a method for the combined treatment of tin-plated copper scrap and copper electrolyte, and invention patent CN110499521B discloses a method for the coordinated purification and treatment of copper electrolyte and copper removal tin slag. The technical principles of these two patents are very similar. First, the metallic tin in the tin-plated copper scrap or copper removal tin slag is used to replace the Cu in the copper electrolyte. 2+ , producing Sn 2+ and sponge copper (very small particle size), and then blow air or oxygen into it to make Sn 2+ Oxidized to Sn 4+ , Sn in solution 4+ Hydrolysis generates β-(SnO2·H2O)5 colloidal precipitate. The disadvantages of this method are that the process is long and the filtration performance of the stannic acid colloidal precipitate in the solution is poor. The high copper content in the copper electrolyte requires a large amount of tin-plated copper scrap or copper-removed tin slag. In addition, the complex composition of tin-plated copper scrap or copper-removed tin slag increases the type and content of impurities in the copper electrolyte.

[0006] In view of the fact that the existing process technology for removing tin from copper electrolyte still has the above-mentioned many problems, the present application now proposes a method for leaching tin from copper electrolyte by oxygen pressure to solve the above-mentioned problems. Summary of the Invention

[0007] The present invention aims to solve the problems raised in the background technology. The purpose of one or more embodiments of this specification is to propose a method for leaching tin from copper electrolyte under oxygen pressure, 2+ Oxidation and hydrothermal decomposition, stannic acid colloid and other flocculants are converted into crystalline tin-containing precipitates. The obtained tin-containing precipitates have stable crystal properties and excellent liquid-solid separation properties, which is beneficial to the subsequent recycling of copper electrolyte.

[0008] Based on the above-mentioned purpose, one or more embodiments of the present specification provide a method for oxygen pressure leaching and tin precipitation of copper electrolyte, comprising: adding a pH regulator to a copper electrolyte containing copper, tin and nickel, stirring and adjusting the pH to 0.5-6 to obtain a mixed slurry; adding the mixed slurry to a high-pressure reactor, introducing an oxygen-containing gas into the high-pressure reactor for oxygen pressure stirring leaching, and obtaining a solid-liquid mixture after the oxygen pressure stirring leaching reaction; performing solid-liquid separation on the solid-liquid mixture, the filtrate being a copper electrolyte purification liquid containing copper and nickel, and the filter residue being a tin precipitation residue.

[0009] According to the method for tin precipitation by oxygen pressure leaching of copper electrolyte of the present invention, the concentration of Cu in the copper electrolyte containing copper, tin and nickel is 10-60 g / L, the concentration of Ni is 20-50 g / L, the concentration of Sn is 0.5-10 g / L, the concentration of As is 0.1-3 g / L, the concentration of Sb is 0-2 g / L, the concentration of Bi is 0-0.5 g / L, the concentration of H2SO4 is 60-200 g / L, and the content of suspended solids is 100-5000 mg / L.

[0010] According to the method for leaching tin from copper electrolyte under oxygen pressure of the present invention, the pH regulator is one or a combination of sodium hydroxide, sodium carbonate and water.

[0011] According to the method for tin precipitation by oxygen pressure leaching of copper electrolyte of the present invention, the oxygen-containing gas is oxygen or air.

[0012] According to the method for leaching tin from copper electrolyte under oxygen pressure of the present invention, the pressure inside the high-pressure reactor in the oxygen pressure stirring leaching reaction is 0.1-2.5 MPa, the reaction temperature is 100-200° C., and the reaction time is 0.5-3 h.

[0013] According to the method for leaching tin from copper electrolyte under oxygen pressure of the present invention, the oxygen pressure stirring leaching reaction is stirred by a mechanical stirrer at a stirring speed of 200-800 r / min.

[0014] According to the method for leaching tin from copper electrolyte with oxygen pressure of the present invention, the solid-liquid separation is performed by a plate-and-frame diaphragm filter press.

[0015] According to the method for leaching tin from copper electrolyte under oxygen pressure of the present invention, the tin slag can be comprehensively recovered by a regeneration and recovery production system for valuable elements.

[0016] According to the method for leaching tin from copper electrolyte under oxygen pressure of the present invention, the filtrate can be sent to the production of copper sulfate and nickel sulfate, and then returned to the copper electrolysis process.

[0017] According to the above, the present invention has the following beneficial effects:

[0018] 1) The present invention utilizes the solution system strengthening conditions such as efficient oxidation and high temperature hydrothermal decomposition provided by high pressure leaching technology to remove Sn from the copper electrolyte. 2+ Oxidation and hydrothermal decomposition, stannic acid colloid and other flocculants are converted into crystalline tin-containing precipitates. The obtained tin-containing precipitates have stable crystal properties and excellent liquid-solid separation performance, which solves the technical problems of colloidal tin-containing hydrates in copper electrolytes causing solution turbidity and difficulty in liquid-solid separation.

[0019] 2) In the process of purifying and removing tin from the copper electrolyte, the present invention does not use any flocculants or add any precipitants, and thus does not introduce any harmful impurities, which is beneficial to the subsequent recycling of the copper electrolyte.

[0020] 3) The present invention achieves the precipitation and slag separation of tin in the copper electrolyte in one step, and components such as copper and nickel remain in the electrolyte. The process is simple, easy to operate, does not generate wastewater and waste residue, and is environmentally friendly. The tin concentration in the copper electrolyte purification solution can be reduced to below 0.05 g / L, and the precipitation tin removal rate is greater than 98%. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate one or more embodiments of this specification or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only one or more embodiments of this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 This is a flow chart of the method for oxygen pressure leaching of tin in copper electrolyte proposed in an embodiment of the present invention. DETAILED DESCRIPTION

[0023] In order to make the objectives, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in conjunction with specific embodiments.

[0024] The following is based on Figure 1 The specific process of the method for tin precipitation by oxygen pressure leaching of copper electrolyte in an embodiment of the present invention is described below.

[0025] The method for leaching tin by oxygen pressure from a copper electrolyte according to an embodiment of the present invention comprises the following steps:

[0026] S1: adding a pH adjuster to a copper electrolyte containing copper, tin and nickel, stirring and adjusting the pH to 0.5-6 to obtain a mixed slurry.

[0027] Optionally, in an embodiment of the present invention, the copper electrolyte containing copper, tin and nickel in step S1 comes from a black copper electrolytic refining process, and the black copper comes from a black copper anode plate (copper content 70%-85%) cast by pyrometallurgical smelting of low-grade miscellaneous copper.

[0028] Optionally, in an embodiment of the present invention, the copper electrolyte containing copper, tin and nickel in step S1, wherein the concentration of Cu is 10-60 g / L, the concentration of Ni is 20-50 g / L, the concentration of Sn is 0.5-10 g / L, the concentration of As is 0.1-3 g / L, the concentration of Sb is 0-2 g / L, the concentration of Bi is 0-0.5 g / L, the concentration of H2SO4 is 60-200 g / L, and the content of suspended solids is 100-5000 mg / L. It should be noted that the above-mentioned substances and element contents are only to meet the need for full disclosure and do not constitute a limitation to the scheme itself. The method provided by the present invention is applicable to copper electrolytes obtained by commercially available and existing processing methods.

[0029] Optionally, in an embodiment of the present invention, the pH adjuster in step S1 is any one of sodium hydroxide, sodium carbonate, and water. From the perspective of production cost, water is preferably used as the pH adjuster. The pH value of the mixed slurry is adjusted to 0.5-6 by stirring. Preferably, controlling the pH value to 2-4 achieves better tin precipitation effect in the copper electrolyte.

[0030] S2: adding the mixed slurry obtained in S1 into a high-pressure reactor, introducing oxygen or air into the high-pressure reactor for oxygen pressure leaching, and stirring the leaching reaction under oxygen pressure for a period of time to obtain a solid-liquid mixture.

[0031] Optionally, in an embodiment of the present invention, the oxygen pressure leaching process of the mixed slurry in step S2 is completed in a high-pressure reactor, and oxygen or air is continuously introduced, the pressure in the reactor is 0.1-2.5 MPa, the reaction temperature is 100-200°C, and the reaction time is 0.5-3 h, so that Sn in the copper electrolyte is reduced to 0.1-2.5 MPa. 2+ After full oxidation and hydrothermal decomposition, flocculants such as stannic acid colloid are converted into crystalline tin-containing precipitates.

[0032] Optionally, in an embodiment of the present invention, oxygen or air is used as the gaseous oxidant in the oxygen pressure leaching process. From the perspective of production cost, air is preferably used as the oxidant.

[0033] Optionally, in an embodiment of the present invention, the pressure inside the reactor is 0.1-2.5 MPa, and the reaction temperature is 100-200°C. The reaction temperature has a significant impact on the tin precipitation effect. As the reaction temperature increases, the particles of the tin-containing precipitate increase in size, and the sedimentation and filtration rates accelerate. That is, the higher the reaction temperature, the better the tin precipitation effect of the copper electrolyte. The pressure inside the reactor can be controlled to meet the reaction temperature. Excessively high pressure is not necessary to avoid production safety hazards.

[0034] Optionally, in an embodiment of the present invention, the reaction time is 0.5 to 3 hours. Preferably, the extension of the reaction time can improve the tin-immersion effect, but after the reaction time exceeds 3 hours, the improvement is not significant.

[0035] Optionally, in an embodiment of the present invention, the mixed slurry is stirred in step S2 to improve reaction efficiency. Optionally, stirring is performed using a mechanical stirrer at a stirring speed of 200 to 800 r / min. Preferably, the stirring speed is 400 to 600 r / min.

[0036] Working principle: In the embodiment of the present invention, oxygen pressure leaching process is used to achieve precipitation and tin removal of copper electrolyte. The main principle of the method of the present invention is: when the pH value is within the range of 0.5 to 6, Sn 4+ Compared with Sn 2+ It is easier to completely hydrolyze into Sn(OH)4; in the process of oxygen pressure leaching, by changing the valence of tin, the continuous introduction of oxygen or air promotes the Sn in the copper electrolyte to 2+ Completely oxidized to more easily hydrolyzed Sn 4+ The special feature of the oxygen pressure leaching process is that the high-pressure and high-temperature conditions provided by the oxygen pressure leaching process can promote the hydrothermal decomposition of Sn(OH)4 into a solid phase of metastannic acid H2SnO3 and / or a solid phase of SnO2, and can also cause flocculants such as undecomposed Sn(OH)4 particles in the solution to flocculate and coagulate, thereby suppressing the formation of β-stannic acid colloid from Sn(OH)4. This avoids the problems of difficulty in filtering and separation caused by the hydrolysis product, colloidal Sn(OH)4, in traditional tin removal methods. The method of the present invention separates tin from the copper electrolyte in the form of SnO2 crystal precipitates and / or Sn(OH)4 flocculent precipitation, while copper and nickel remain in the copper electrolyte in the form of sulfates, thereby efficiently separating tin from copper and nickel in the electrolyte. This method can efficiently remove tin by precipitation without introducing other impurities that affect the copper electrolysis process.

[0037] The reaction process equation is as follows:

[0038] 2Sn 2+ +O2+4H + →2Sn 4+ +2H2O;

[0039] Sn 4+ +H2O→Sn(OH)4+4H + ;

[0040] Sn(OH)4→H2SnO3+H2O;

[0041] Sn(OH)4→SnO2+2H2O.

[0042] S3: The solid-liquid mixture obtained in S2 is subjected to solid-liquid separation, and the filtrate is a purified copper electrolyte solution containing copper and nickel; the filter residue is tin precipitate residue, which is sent to a tin regeneration and recovery production system.

[0043] Optionally, in an embodiment of the present invention, in step S3, the solid-liquid separation of the solid-liquid mixture is performed using a plate-and-frame diaphragm filter press. Compared to conventional tin removal methods for copper electrolytes that employ the addition of flocculants, the present invention utilizes an oxygen pressure leaching process to purify the copper electrolyte. This significantly increases the filtration rate of the resulting solid-liquid mixture, allows for smoother liquid-solid separation, and produces a crystalline tin-containing precipitate.

[0044] Optionally, in an embodiment of the present invention, the filter residue obtained by solid-liquid separation in step S3 has a tin content of more than 40% and is enriched with impurity elements such as arsenic, antimony, and bismuth in the electrolyte, and can be sent to a tin regeneration and recovery production system for comprehensive recovery of valuable elements.

[0045] Optionally, in an embodiment of the present invention, the solid suspended matter content in the filtrate obtained by solid-liquid separation in step S3 is less than 10 mg / L, the tin content is less than 0.05 g / L, and the precipitation tin removal rate is greater than 98%; the copper electrolytic purified liquid after tin removal can be sent to the production of copper sulfate and nickel sulfate, and then returned to the copper electrolysis process.

[0046] The present invention is described below with reference to specific examples. It should be noted that these examples are merely illustrative and do not limit the present invention in any way.

[0047] Example 1

[0048] 500 mL of copper electrolyte with a chemical composition of 45.2 g / L Cu, 31.6 g / L Ni, 6.3 g / L Sn, 1.7 g / L As, 0.8 g / L Sb, 126 g / L H2SO4, and a solid suspended matter content of 4200 mg / L was measured, and sodium hydroxide was added to adjust the pH value to 4.3. A 3L high-pressure reactor was used and oxygen was introduced for pressure leaching. The pressure leaching conditions were as follows: reactor pressure 0.8 MPa, reaction temperature 150°C, reaction time 1 h. After leaching, the mixture was filtered to obtain leached residue (tin precipitate residue) and filtrate (copper electrolyte purification liquid).

[0049] After analysis and detection: the mass concentration of Sn in the copper electrolyte purification liquid is 0.03g / L, the precipitation removal rate of tin is 99.1%, the precipitation loss rates of copper and nickel are 2.1% and 1.7% respectively, and the solid suspended matter content in the purification liquid is 7mg / L.

[0050] Example 2

[0051] 500 mL of copper electrolyte with a chemical composition of 45.2 g / L Cu, 31.6 g / L Ni, 6.3 g / L Sn, 1.7 g / L As, 0.8 g / L Sb, 126 g / L H2SO4, and a solid suspended matter content of 4200 mg / L was measured, and water was added to adjust the pH value to 0.6. A 3L high-pressure reactor was used and oxygen was introduced for pressure leaching. The pressure leaching conditions were as follows: reactor pressure 1.2 MPa, reaction temperature 180°C, reaction time 2 h. After leaching was completed, the solution was filtered to obtain leached residue (tin precipitate residue) and filtrate (copper electrolyte purification liquid).

[0052] After analysis and detection: the mass concentration of Sn in the copper electrolyte purification liquid is 0.02g / L, the precipitation removal rate of tin is 99.7%, the precipitation loss rates of copper and nickel are 1.8% and 1.1% respectively, and the solid suspended matter content in the purification liquid is 5mg / L.

[0053] Example 3

[0054] 500 mL of copper electrolyte with a chemical composition of 45.2 g / L Cu, 31.6 g / L Ni, 6.3 g / L Sn, 1.7 g / L As, 0.8 g / L Sb, 126 g / L H2SO4, and a solid suspended matter content of 4200 mg / L was measured, and sodium carbonate was added to adjust the pH value to 2.3. A 3L high-pressure reactor was used and air was introduced for pressure leaching. The pressure leaching conditions were as follows: reactor pressure 0.7 MPa, reaction temperature 140°C, reaction time 3 h. After leaching, the mixture was filtered to obtain leached residue (tin precipitate residue) and filtrate (copper electrolyte purification liquid).

[0055] After analysis and detection: the mass concentration of Sn in the copper electrolyte purification liquid is 0.04g / L, the precipitation removal rate of tin is 98.3%, the precipitation loss rates of copper and nickel are 2.9% and 1.7% respectively, and the solid suspended matter content in the purification liquid is 9mg / L.

[0056] Example 4

[0057] 500 mL of copper electrolyte with a chemical composition of 32.7 g / L Cu, 41.3 g / L Ni, 3.5 g / L Sn, 0.9 g / L As, 0.4 g / L Sb, 98 g / L H2SO4, and a solid suspended matter content of 2300 mg / L was measured, and sodium hydroxide was added to adjust the pH value to 5.9. A 3L high-pressure reactor was used and oxygen was introduced for pressure leaching. The pressure leaching conditions were as follows: reactor pressure 0.5 MPa, reaction temperature 130°C, reaction time 2 h. After leaching was completed, the solution was filtered to obtain leached residue (tin precipitate residue) and filtrate (copper electrolyte purification liquid).

[0058] After analysis and detection: the mass concentration of Sn in the copper electrolyte purification solution is 0.02g / L, the precipitation removal rate of tin is 99.3%, the precipitation loss rates of copper and nickel are 2.5% and 1.9% respectively, and the solid suspended matter content in the purification solution is 5mg / L.

[0059] Example 5

[0060] 500 mL of copper electrolyte with a chemical composition of 32.7 g / L Cu, 41.3 g / L Ni, 3.5 g / L Sn, 0.9 g / L As, 0.4 g / L Sb, 98 g / L H2SO4, and 2300 mg / L solid suspended matter was measured, and sodium carbonate was added to adjust the pH value to 4.3. A 3L high-pressure reactor was used and air was introduced for pressure leaching. The pressure leaching conditions were as follows: reactor pressure 2.5 MPa, reaction temperature 200°C, reaction time 0.5 h. After leaching, the mixture was filtered to obtain leached residue (tin precipitate residue) and filtrate (copper electrolyte purification liquid).

[0061] After analysis and detection: the mass concentration of Sn in the copper electrolyte purification solution is 0.01g / L, the precipitation removal rate of tin is 99.7%, the precipitation loss rates of copper and nickel are 1.3% and 0.5% respectively, and the solid suspended matter content in the purification solution is 3mg / L.

[0062] Example 6

[0063] 500 mL of copper electrolyte with a chemical composition of 32.7 g / L Cu, 41.3 g / L Ni, 3.5 g / L Sn, 0.9 g / L As, 0.4 g / L Sb, 98 g / L H2SO4, and 2300 mg / L solid suspended matter was measured, water was added to adjust the pH value to 1.2, and pressure leaching was carried out in a 3L high-pressure reactor and air was introduced. The pressure leaching conditions were as follows: pressure in the reactor 0.1 MPa, reaction temperature 100°C, reaction time 3 h, and filtration after leaching to obtain leached residue (tin precipitate residue) and filtrate (copper electrolyte purification liquid).

[0064] After analysis and detection: the mass concentration of Sn in the copper electrolyte purification liquid is 0.04g / L, the precipitation removal rate of tin is 98.2%, the precipitation loss rates of copper and nickel are 3.7% and 1.9% respectively, and the solid suspended matter content in the purification liquid is 9mg / L.

[0065] Comparative Example 1

[0066] Other conditions are the same as those in Example 1, except that the copper electrolyte is purified and tin removed by conventional atmospheric pressure leaching instead of oxygen pressure leaching, with a reaction temperature of 80° C. and a reaction pressure of atmospheric pressure.

[0067] The obtained copper electrolyte purified liquid is turbid and difficult to filter. Analysis and detection show that the solid suspended matter content in the filtrate is 2137 mg / L, the mass concentration of Sn in the copper electrolyte purified liquid is 4.13 g / L, the precipitation tin removal rate is 31.2%, and the precipitation loss rates of copper and nickel are 38.3% and 25.1%, respectively. In other words, if the pressure leaching process purification technology is not adopted, the precipitation tin removal effect of the copper electrolyte is unsatisfactory and the filtrate is turbid, and the subsequent utilization of the copper electrolyte is not utilized.

[0068] Comparative Example 2

[0069] Other conditions were the same as in Example 2, except that oxygen was not introduced during the pressure leaching process to oxidize the copper electrolyte.

[0070] The obtained copper electrolyte purified solution was turbid and difficult to filter. After analysis and detection, the solid suspended matter content in the filtrate was 1259 mg / L, the mass concentration of Sn in the copper electrolyte purified solution was 3.27 g / L, the precipitation removal rate of tin was 47.3%, and the precipitation loss rates of copper and nickel were 24.5% and 17.3%, respectively. That is, no oxygen or air was introduced during the pressure leaching process, and the Sn in the copper electrolyte was 2+ The oxidation effect is poor, which is not conducive to the formation of Sn(OH)4 and its hydrothermal decomposition and flocculation-precipitation. The precipitation tin removal effect is not ideal and the filtrate is turbid.

[0071] Comparative Example 3

[0072] Other conditions were the same as in Example 3, except that sodium carbonate was added to adjust the pH value to 7.7.

[0073] The obtained copper electrolyte purified liquid was slightly turbid and had average filtration performance. Analysis and testing showed that the solid suspended matter content in the filtrate was 879 mg / L, the mass concentration of Sn in the copper electrolyte purified liquid was 1.57 g / L, the precipitation tin removal rate was 61.3%, and the precipitation loss rates of copper and nickel were 64.2% and 43.7%, respectively. In other words, if the pH value of the copper electrolyte was controlled too high to be alkaline, the tin-containing precipitate might have dissolved back, resulting in an unsatisfactory precipitation tin removal effect and also causing precipitation loss of copper ions and nickel ions in the electrolyte.

[0074] The one or more embodiments of this specification are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of one or more embodiments of this specification shall be included within the scope of protection of this disclosure.

Claims

1. A method for leaching tin from copper electrolyte under oxygen pressure, characterized in that: include: Adding a pH regulator to a copper electrolyte containing copper, tin, and nickel, stirring and adjusting the pH to 0.5-6 to obtain a mixed slurry; The mixed slurry is added to a high-pressure reactor, and oxygen-containing gas is introduced into the high-pressure reactor to perform oxygen pressure stirring leaching. A solid-liquid mixture is obtained after oxygen pressure stirring leaching reaction; The solid-liquid mixture is subjected to solid-liquid separation, the filtrate is a copper electrolyte purification liquid containing copper and nickel, and the filter residue is tin precipitation residue; In the oxygen pressure stirring leaching reaction, the pressure inside the high-pressure reactor is 0.1-2.5 MPa, the reaction temperature is 100-200° C., and the reaction time is 0.5-3 h.

2. The method for leaching tin from copper electrolyte under oxygen pressure according to claim 1, wherein: The copper electrolyte containing copper, tin and nickel has a Cu concentration of 10 to 60 g / L, a Ni concentration of 20 to 50 g / L, a Sn concentration of 0.5 to 10 g / L, an As concentration of 0.1 to 3 g / L, an Sb concentration of 0 to 2 g / L, a Bi concentration of 0 to 0.5 g / L, an H2SO4 concentration of 60 to 200 g / L, and a suspended solid content of 100 to 5000 mg / L.

3. The method for leaching tin from copper electrolyte under oxygen pressure according to claim 1, wherein: The pH regulator is one or a combination of sodium hydroxide, sodium carbonate and water.

4. The method for leaching tin from copper electrolyte under oxygen pressure according to claim 1, wherein: The oxygen-containing gas is oxygen or air.

5. The method for leaching tin from copper electrolyte under oxygen pressure according to claim 1, wherein: The oxygen pressure stirring leaching reaction is stirred by a mechanical stirrer at a stirring speed of 200-800 r / min.

6. The method for leaching tin from copper electrolyte under oxygen pressure according to claim 1, wherein: The solid-liquid separation is carried out by a plate-and-frame diaphragm filter press.

7. The method for leaching tin from copper electrolyte under oxygen pressure according to claim 1, wherein: The tin slag can be used to comprehensively recover valuable elements through a regeneration and recovery production system.

8. The method for leaching tin from copper electrolyte under oxygen pressure according to claim 1, wherein: The filtrate can be sent to the production of copper sulfate and nickel sulfate, and then returned to the copper electrolysis process.

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