Impurity removal and recovery for electrowon nickel anolyte

Abstract

Provided in the present application is an impurity removal and recovery method for an electrowon nickel anolyte. The impurity removal and recovery method comprises the following steps: (1) mixing an electrowon nickel anolyte with liquid caustic soda, performing solid-liquid separation to obtain nickel hydroxide and a filtrate, evaporating the filtrate to obtain sodium sulfate, and mixing the electrowon nickel anolyte with a nickel source to obtain a mixed solution; (2) mixing the mixed solution with a barium salt to remove lead; (3) using the nickel hydroxide to adjust the pH of a material obtained after the lead removal, so as to obtain a solution to be subjected to arsenic removal, and mixing the solution to be subjected to arsenic removal with polymeric ferric sulfate to remove arsenic; and (4) mixing a material obtained after the arsenic removal with an oxidant to obtain a solution to be subjected to iron removal, performing solid-liquid separation on the solution to be subjected to iron removal to obtain a catholyte with lead, arsenic and iron removed and iron-containing dross, and supplementing said catholyte with sodium sulfate for reuse in electrowinning nickel processes. The method of the present application can efficiently and quickly remove lead, arsenic and iron from electrowon nickel anolytes and recycle same.

Description

A method for removing impurities and recovering electrolytic nickel anolyte Technical Field

[0001] This application belongs to the field of nickel hydrometallurgical technology and relates to a method for removing impurities and recovering electrolytic nickel anolyte. Background Technology

[0002] Electrolytic nickel products are widely used in electroplating, batteries, and high-temperature alloys. To ensure optimal application in these specialized fields, the impurity content of electrolytic nickel products must be strictly controlled. Impurities are typically introduced through the new electrolytic solution and the anode plate. Replacing the anode plate with a titanium-coated anode plate can effectively prevent impurity problems caused by the anode plate; however, titanium-coated anode plates are expensive and have a short service life, limiting their industrial application.

[0003] Currently, electrowinning nickel mainly uses multi-element alloy anode plates. The electrowinning process may introduce impurities such as lead, arsenic, and iron. Therefore, it is inevitable to mix the electrowinning solution and the anode solution and then perform impurity removal treatment before returning them to the electrowinning process to obtain high-purity electrowinning nickel products.

[0004] CN117107341A discloses a method for regenerating and recycling electrolytic nickel anolyte, which uses electrolytic nickel anolyte in the back-extraction section of a nickel sulfate extraction enrichment line for back-extraction of nickel-loaded p507 extractant. Specifically, it includes: (1) First-stage back-extraction: using electrolytic nickel anolyte to back-extract nickel-loaded p507 extractant to obtain a first-stage back-extraction phase and a first-stage p507 organic phase; (2) Second-stage back-extraction: using acid to back-extract the first-stage p507 organic phase to obtain a second-stage back-extraction phase and a second-stage p507 organic phase; (3) Electrolytic deposition: detecting the impurity content in the first-stage back-extraction phase, and when the impurity content meets the control standard, returning the second-stage back-extraction phase to the first-stage back-extraction, mixing it with the electrolytic nickel anolyte to be used as the back-extraction agent for the first-stage back-extraction, and using the first-stage back-extraction phase as the cathode liquid for electrolytic nickel deposition to obtain nickel and electrolytic nickel anolyte.

[0005] CN119194538A discloses a method for removing lead and replenishing nickel in electrolytic nickel anolyte. The method involves mixing the electrolytic anolyte with refined nickel sulfate degreasing solution and nickel carbonate slurry, introducing air, controlling the temperature, and then entering an acid dissolution tank for lead removal. The acid-dissolved solution is then filtered through an acid dissolution filter press. The resulting primary filtrate is pumped into a precision filter, and the resulting secondary filtrate enters a secondary filtrate storage tank. The secondary filtrate is then pumped into a cathode liquid tank via a secondary filtrate transfer pump. The resulting cathode liquid is then used as the cathode liquid in the electrolytic electrodeposition process.

[0006] The above-mentioned method has a long impurity removal time, requires high impurity removal efficiency, and is relatively complicated. As a result, the returned electrowinning solution cannot keep up with the electrowinning consumption, leading to a decrease in production capacity and additional economic losses. Summary of the Invention

[0007] This application provides a method for removing impurities and recovering nickel anolyte by electrowinning. The method described in this application can efficiently and quickly remove lead, arsenic and iron from the nickel anolyte by electrowinning, ensuring the timely supply of the electrowinning solution, guaranteeing the smooth progress of the electrowinning reaction, and avoiding the reduction of production capacity due to the impurity removal process.

[0008] In a first aspect, this application provides a method for removing impurities and recovering nickel anolyte by electrowinning, the method comprising the following steps:

[0009] (1) Take the first electrolytic nickel anolyte and mix it with liquid alkali, and then perform a first solid-liquid separation treatment to obtain nickel hydroxide and filtrate. Evaporate the filtrate to obtain sodium sulfate; take the second electrolytic nickel anolyte and mix it with a nickel source to obtain a mixed solution;

[0010] (2) Mix the mixed solution obtained in step (1) with barium salt and perform lead removal treatment;

[0011] (3) After adjusting the pH of the material obtained after lead removal treatment in step (2) with nickel hydroxide obtained in step (1), the arsenic removal solution is obtained. The arsenic removal solution is then mixed with polyferric sulfate for arsenic removal treatment.

[0012] (4) The material obtained after the arsenic removal treatment in step (3) is mixed with an oxidant to obtain an iron removal solution. The iron removal solution is subjected to a second solid-liquid separation treatment to obtain a catholyte containing lead, arsenic and iron and iron-containing slag. Sodium sulfate obtained in step (1) is added to the catholyte containing lead, arsenic and iron and reused in the nickel electrowinning process.

[0013] In this application, the first solid-liquid separation process and the second solid-liquid separation process each independently employ pressure filtration, vacuum filtration, or filtration, with pressure filtration being an option.

[0014] The nickel anolyte described in this application is the anolyte produced by the anode during the nickel electrolysis process. The first and second nickel anolytes in this application can be selected from the same nickel anolyte or from different nickel anolytes. The amount and ratio of the two are not limited in any way. If the nickel hydroxide and sodium sulfate produced by the first nickel anolyte are in excess, they can be used in the impurity removal and recovery process of the nickel anolyte in the next process.

[0015] The impurity removal and recovery method for electrowinning nickel anolyte described in this application, through the rational allocation of each step, sequentially performs lead, arsenic, and iron precipitation on the electrowinning nickel anolyte. This achieves timely and efficient removal of lead, arsenic, and iron impurities from the electrowinning nickel anolyte, significantly shortening the impurity removal time. It ensures a timely supply of the electrowinning solution, guarantees the smooth progress of the electrowinning reaction, and avoids capacity reduction due to the impurity removal process. The impurity removal and recovery method described in this application achieves cyclical production, realizing the purpose of impurity removal without losing any auxiliary materials required for electrowinning, such as sodium sulfate, thus helping to reduce production costs.

[0016] In one embodiment, the mass concentration of nickel ions in the first and second electrolytic nickel anolytes in step (1) is independently 75 g / L to 85 g / L, for example: 75 g / L, 78 g / L, 80 g / L, 82 g / L or 85 g / L, but not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0017] In one embodiment, the mass concentration of sodium sulfate in the first and second electrolytic nickel anolytes in step (1) is independently 80 g / L to 100 g / L, for example: 80 g / L, 85 g / L, 90 g / L, 95 g / L or 100 g / L, but not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0018] In one embodiment, the pH of the first and second electrolytic nickel anolytes in step (1) is independently 0 to 1.5, for example: 0, 0.1, 0.5, 0.8, 1 or 1.5, etc., but not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0019] In one embodiment, the mass concentration of the liquid alkali in step (1) is 30% to 42%, for example: 30%, 32%, 35%, 40% or 42%, etc., but not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0020] In one embodiment, the molar ratio of sodium hydroxide in the liquid alkali in step (1) to nickel ions in the first electrolytic nickel anolyte is (2 to 2.2):1, for example: 2:1, 2.05:1, 2.1:1, 2.15:1 or 2.2:1, etc., but not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0021] In one embodiment, the nickel source in step (1) includes nickel sulfate crystals and / or nickel sulfate solution.

[0022] In one embodiment, the mass concentration of nickel ions in the nickel sulfate solution in step (1) is 100 g / L to 105 g / L, for example: 100 g / L, 101 g / L, 102 g / L, 103 g / L, 104 g / L or 105 g / L, etc., but not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0023] In one embodiment, the pH of the nickel sulfate solution in step (1) is 3.5 to 4.5, for example: 3.5, 3.8, 4, 4.2 or 4.5, etc., but not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0024] In one embodiment, the mass concentration of nickel ions in the mixed solution in step (1) is 80 g / L to 90 g / L, for example: 80 g / L, 82 g / L, 85 g / L, 88 g / L or 90 g / L, etc., but not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0025] In one embodiment, the mass concentration of sodium sulfate in the mixed solution in step (1) is 60 g / L to 85 g / L, for example: 60 g / L, 65 g / L, 70 g / L, 80 g / L or 85 g / L, but not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0026] In one embodiment, the pH of the mixed solution in step (1) is 0 to 2, for example: 0, 0.5, 1, 1.5 or 2, but not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0027] In one embodiment, the barium salt in step (2) includes barium carbonate.

[0028] In one embodiment, the mass-to-volume ratio of the barium salt to the mixed solution is 0.1 g / L to 0.4 g / L, for example: 0.1 g / L, 0.15 g / L, 0.2 g / L, 0.3 g / L or 0.4 g / L, etc., but not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0029] In one embodiment, the first stirring is performed during the lead removal process described in step (2).

[0030] In one embodiment, the first stirring time is 20 min to 40 min, for example: 20 min, 25 min, 30 min, 35 min or 40 min, etc., but not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0031] In one embodiment, the temperature of the lead removal process in step (2) is 50°C to 70°C, for example: 50°C, 55°C, 60°C, 65°C or 70°C, but not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0032] In one embodiment, the pH in step (3) is 3.5 to 4.5, for example: 3.5, 3.8, 4, 4.2 or 4.5, etc., but not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0033] In one embodiment, the mass concentration of nickel ions in the arsenic removal solution in step (3) is 100 g / L to 105 g / L, for example: 100 g / L, 101 g / L, 102 g / L, 103 g / L, 104 g / L or 105 g / L, etc., but not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0034] In one embodiment, the mass-to-volume ratio of polyferric sulfate to the arsenic removal solution in step (3) is 0.3 g / L to 0.6 g / L, for example: 0.3 g / L, 0.35 g / L, 0.4 g / L, 0.5 g / L or 0.6 g / L, etc., but not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0035] In one embodiment, a second stirring is performed during the arsenic removal process described in step (3).

[0036] In one embodiment, the second stirring time is 20 min to 40 min, for example: 20 min, 25 min, 30 min, 35 min or 40 min, etc., but not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0037] In one embodiment, the temperature of the arsenic removal treatment in step (3) is 50°C to 70°C, for example: 50°C, 55°C, 60°C, 65°C or 70°C, but not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0038] In one embodiment, the oxidant in step (4) includes a hydrogen peroxide solution.

[0039] In one embodiment, the volume ratio of the oxidant in step (4) to the material obtained after arsenic removal treatment is 10 mL / L to 20 mL / L, for example: 10 mL / L, 12 mL / L, 15 mL / L, 18 mL / L or 20 mL / L, etc., but not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0040] In one embodiment, the mass concentration of the hydrogen peroxide solution is 30-42%, for example: 30%, 32%, 35%, 40% or 42%, etc., but not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0041] In one embodiment, the mass-to-volume ratio of sodium sulfate to catholyte for removing lead, arsenic and iron in step (4) is 80 g / L to 100 g / L, for example: 80 g / L, 85 g / L, 90 g / L, 95 g / L or 100 g / L, etc., but not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0042] Compared with the prior art, this application has the following beneficial effects.

[0043] (1) The impurity removal and recovery method described in this application can achieve rapid impurity removal during the nickel electrowinning process, allowing the electrowinning solution to flow more quickly, reducing concentration polarization and ensuring a stable and high liquid level difference between the cathode and anode, effectively preventing hydrogen ions from migrating to the cathode and thus increasing the porosity of the nickel plate. At the same time, the rapid flow of the electrowinning solution can effectively avoid the accumulation of impurities in the electrowinning cell, thereby reducing the precipitation of impurities at the cathode and improving the product quality of the electrowinning nickel.

[0044] (2) The method for removing impurities from the electrolytic nickel anode liquid described in this application can effectively remove lead, arsenic and iron impurities in the same reactor without the need for complicated operating procedures and liquid transfer, thus reducing labor intensity and improving work efficiency.

[0045] (3) The method for removing impurities and recovering nickel anolyte described in this application can achieve a lead concentration of less than 1.9 mg / L, an arsenic concentration of less than 0.2 mg / L, and an iron concentration of less than 1.9 mg / L in the cathode solution. By adjusting the amount of material added during the recovery process, the lead concentration in the cathode solution can be reduced to less than 1.3 mg / L, the arsenic concentration to less than 0.1 mg / L, and the iron concentration to less than 1.2 mg / L. Attached Figure Description

[0046] Figure 1 is a schematic diagram of the process flow of the method for removing impurities and recovering electrolytic nickel anolyte provided in the embodiments of this application. Detailed Implementation

[0047] The technical solution of this application will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely to help understand this application and should not be regarded as specific limitations on this application.

[0048] The specific composition of the electrolytic nickel anode solution used in the embodiments and comparative examples of this application is as follows:

[0049] Ni: 82 g / L, Sodium sulfate: 93.5 g / L, Pb: 3.5 mg / L, As: 0.4 mg / L, Fe: 2.8 mg / L, pH: 0.85.

[0050] Example 1

[0051] This embodiment provides a method for removing impurities and recovering nickel anolyte from electrolytic nickel. The process flow of the method is shown in Figure 1, and the method includes the following steps:

[0052] (1) Mix the electrolytic nickel anolyte with a 35% (w / w) liquid alkali solution (the liquid alkali contains OH-). - The nickel anolyte contains nickel hydroxide in a molar ratio of 2:1 (Ni in the electrolytic nickel anolyte is 2:1). After pressure filtration, nickel hydroxide and filtrate are obtained. The filtrate is evaporated to obtain sodium sulfate. The electrolytic nickel anolyte is then mixed with a nickel sulfate solution with a mass concentration of 102 g / L and a pH of 4 to obtain a mixed solution with a nickel mass concentration of 86 g / L, a sodium sulfate mass concentration of 72 g / L, and a pH of 1.2.

[0053] (2) At 60℃, barium carbonate was mixed with the mixed solution to obtain a barium carbonate mass concentration of 0.1 g / L in the solution, and the solution was stirred for 30 min to remove lead.

[0054] (3) At 60°C, the pH of the material obtained after lead removal treatment was adjusted to 4 using the nickel hydroxide obtained in step (1), and polyferric sulfate (PFS) was added with a mass concentration of 0.3 g / L. The mixture was stirred for 30 min to remove arsenic.

[0055] (4) At 60°C, a 30% hydrogen peroxide solution was added to the material obtained after arsenic removal treatment to obtain an iron removal solution. The volume ratio of the hydrogen peroxide solution to the material obtained after arsenic removal treatment was 10 mL / L. After stirring for 30 min, the solution was filtered to obtain a catholyte containing lead, arsenic and iron and iron-containing slag. The sodium sulfate obtained in step (1) was added to the catholyte containing lead, arsenic and iron. The sodium sulfate concentration was 90 g / L and it was reused in the nickel electrowinning process.

[0056] Example 2

[0057] This embodiment provides a method for removing impurities and recovering nickel anolyte from electrolytic nickel. The process flow of the method is shown in Figure 1, and the method includes the following steps:

[0058] (1) Mix the electrolytic nickel anolyte with a 35% (w / w) liquid alkali solution (the liquid alkali contains OH-). - The nickel anolyte contains nickel hydroxide in a molar ratio of 2.2:1 (Ni in the electrolytic nickel anolyte is 2.2:1). After pressure filtration, nickel hydroxide and filtrate are obtained. The filtrate is evaporated to obtain sodium sulfate. The electrolytic nickel anolyte is then mixed with a nickel sulfate solution with a mass concentration of 105 g / L and a pH of 3.5 to obtain a mixed solution with a nickel mass concentration of 80 g / L, a sodium sulfate mass concentration of 60 g / L, and a pH of 2.

[0059] (2) At 70℃, barium carbonate was mixed with the mixed solution to obtain a barium carbonate mass concentration of 0.4 g / L in the solution, and the solution was stirred to remove lead for 40 min.

[0060] (3) At 70°C, the pH of the material obtained after lead removal treatment was adjusted to 3.5 using the nickel hydroxide obtained in step (1), and polyferric sulfate (PFS) was added with a mass concentration of 0.6 g / L. The mixture was stirred for 30 min to remove arsenic.

[0061] (4) At 70°C, a 35% hydrogen peroxide solution is added to the material obtained after arsenic removal treatment to obtain an iron removal solution. The volume ratio of the hydrogen peroxide solution to the material obtained after arsenic removal treatment is 20 mL / L. After stirring for 30 min, the solution is filtered to obtain a catholyte with lead, arsenic and iron removed and iron-containing slag. The sodium sulfate obtained in step (1) is added to the catholyte with lead, arsenic and iron removed. The sodium sulfate concentration is 100 g / L and it is reused in the nickel electrowinning process.

[0062] Example 3

[0063] This embodiment provides a method for removing impurities and recovering nickel anolyte from electrolytic nickel. The process flow of the method is shown in Figure 1, and the method includes the following steps:

[0064] (1) Mix the electrolytic nickel anolyte with a 42% (w / w) liquid alkali solution (the liquid alkali contains OH-). - The nickel anolyte contains nickel hydroxide in a molar ratio of 2.1:1 (Ni in the electrolytic nickel anolyte is 2.1:1). After pressure filtration, nickel hydroxide and filtrate are obtained. The filtrate is then evaporated to obtain sodium sulfate. The electrolytic nickel anolyte is then mixed with a nickel sulfate solution with a mass concentration of 100 g / L and a pH of 4.5 to obtain a mixed solution with a nickel mass concentration of 90 g / L, a sodium sulfate mass concentration of 80 g / L, and a pH of 0.8.

[0065] (2) At 50℃, barium carbonate was mixed with the mixed solution to obtain a barium carbonate mass concentration of 0.3 g / L in the solution, and the solution was stirred to remove lead for 40 min.

[0066] (3) At 50°C, the pH of the material obtained after lead removal treatment was adjusted to 4.5 using the nickel hydroxide obtained in step (1), and polyferric sulfate (PFS) was added with a mass concentration of 0.6 g / L. The mixture was stirred for 30 min to remove arsenic.

[0067] (4) At 50°C, a hydrogen peroxide solution with a mass concentration of 42% was added to the material obtained after arsenic removal treatment to obtain an iron removal solution. The volume ratio of the hydrogen peroxide solution to the material obtained after arsenic removal treatment was 20 mL / L. After stirring for 30 min, the solution was filtered to obtain a catholyte with lead, arsenic and iron removed and iron-containing slag. The sodium sulfate obtained in step (1) was added to the catholyte with lead, arsenic and iron removed. The sodium sulfate concentration was 80 g / L and it was reused in the nickel electrowinning process.

[0068] Example 4

[0069] This embodiment provides a method for removing impurities and recovering nickel anolyte from electrolytic nickel. The process flow of the method is shown in Figure 1, and the method includes the following steps:

[0070] (1) Mix the electrolytic nickel anolyte with a 35% (w / w) liquid alkali solution (the liquid alkali contains OH-). - The nickel anolyte contains nickel hydroxide in a molar ratio of 2:1 (Ni in the electrolytic nickel anolyte is 2:1). After pressure filtration, nickel hydroxide and filtrate are obtained. The filtrate is evaporated to obtain sodium sulfate. The electrolytic nickel anolyte is then mixed with a nickel sulfate solution with a mass concentration of 102 g / L and a pH of 4 to obtain a mixed solution with a nickel mass concentration of 86 g / L, a sodium sulfate mass concentration of 72 g / L, and a pH of 1.2.

[0071] (2) At 60℃, barium carbonate was mixed with the mixed solution to obtain a barium carbonate mass concentration of 0.4 g / L in the solution, and the solution was stirred to remove lead for 30 min.

[0072] (3) At 60°C, the pH of the material obtained after lead removal treatment was adjusted to 4 using the nickel hydroxide obtained in step (1), and polyferric sulfate was added with a mass concentration of 0.6 g / L. The mixture was stirred for 30 min to remove arsenic.

[0073] (4) At 60°C, a hydrogen peroxide solution with a mass concentration of 32% was added to the material obtained after arsenic removal treatment to obtain an iron removal solution. The volume ratio of the hydrogen peroxide solution to the material obtained after arsenic removal treatment was 20 mL / L. After stirring for 30 min, the solution was filtered to obtain a catholyte with lead, arsenic and iron removed and iron-containing slag. The sodium sulfate obtained in step (1) was added to the catholyte with lead, arsenic and iron removed. The sodium sulfate concentration was 90 g / L and it was reused in the nickel electrowinning process.

[0074] Example 5

[0075] The only difference between this embodiment and Example 1 is that the mass concentration of barium carbonate is 0.05 g / L; all other conditions and parameters are exactly the same as in Example 1.

[0076] Example 6

[0077] The only difference between this embodiment and Example 1 is that the mass concentration of barium carbonate is 0.5 g / L; all other conditions and parameters are exactly the same as in Example 1.

[0078] Example 7

[0079] The only difference between this embodiment and Example 1 is that the mass concentration of polyferric sulfate is 0.2 g / L, while the other conditions and parameters are exactly the same as in Example 1.

[0080] Example 8

[0081] The only difference between this embodiment and Example 1 is that the mass concentration of polyferric sulfate is 0.7 g / L, while the other conditions and parameters are exactly the same as in Example 1.

[0082] Example 9

[0083] The only difference between this embodiment and Embodiment 1 is that the volume concentration of hydrogen peroxide in the solution to be iron removed is 5 mL / L; all other conditions and parameters are exactly the same as in Embodiment 1.

[0084] Example 10

[0085] The only difference between this embodiment and Embodiment 1 is that the volume concentration of hydrogen peroxide in the solution to be iron removed is 30 mL / L. All other conditions and parameters are exactly the same as in Embodiment 1.

[0086] Comparative Example 1

[0087] The only difference between this comparative example and Example 1 is that polyferric sulfate was added first to remove arsenic, followed by barium carbonate to remove lead. All other conditions and parameters are exactly the same as in Example 1.

[0088] Comparative Example 2

[0089] The only difference between this comparative example and Example 1 is that hydrogen peroxide was added first to remove iron, followed by polyferric sulfate to remove arsenic. All other conditions and parameters are exactly the same as in Example 1.

[0090] Comparative Example 3

[0091] The only difference between this comparative example and Example 1 is that hydrogen peroxide was added first to remove iron, followed by barium carbonate to remove lead and polyferric sulfate to remove arsenic. All other conditions and parameters are exactly the same as in Example 1.

[0092] Performance testing:

[0093] The mass concentrations of lead, arsenic, and iron in the catholyte used for lead, arsenic, and iron removal were tested, and the results are shown in Table 1.

[0094] Table 1

[0095] As shown in Table 1, and based on Examples 1-10, the method for removing impurities and recovering the electrolytic nickel anolyte described in this application can achieve a lead concentration of less than 1.9 mg / L, an arsenic concentration of less than 0.2 mg / L, and an iron concentration of less than 1.9 mg / L in the cathode solution. By adjusting the amount of material added during the recovery process, the lead concentration in the cathode solution can be reduced to less than 1.3 mg / L, the arsenic concentration to less than 0.1 mg / L, and the iron concentration to less than 1.2 mg / L.

[0096] A comparison of Examples 1 and 5-6 shows that the amount of barium salt added during the impurity removal and recovery process of the electrolytic nickel anolyte described in this application affects the impurity removal and recovery effect. When the amount of barium salt added is controlled between 0.1 g / L and 0.4 g / L, the lead removal effect is better. If the amount of barium salt added is too large, the lead removal effect is not significant compared to the lead removal effect when the amount of barium salt added is 0.4 g / L. If the amount of barium salt added is too small, the lead removal effect is not significant.

[0097] A comparison of Examples 1 and 7-8 shows that the amount of polyferric sulfate added affects the impurity removal and recovery effect during the impurity removal and recovery process of the electrolytic nickel anolyte described in this application. When the amount of polyferric sulfate added is controlled between 0.3 g / L and 0.6 g / L, the arsenic removal effect is better. If the amount of polyferric sulfate added is too large, the gain is not significant compared to the arsenic removal effect when the amount of polyferric sulfate added is 0.6 g / L. If the amount of polyferric sulfate added is too small, the arsenic removal effect is not significant.

[0098] A comparison of Examples 1 and 9-10 shows that in the impurity removal and recovery process of the electrolytic nickel anolyte described in this application, the amount of oxidant (hydrogen peroxide) added affects the impurity removal and recovery effect. When the amount of oxidant added is controlled at 10 mL / L to 20 mL / L, the iron removal effect is better. If the amount of oxidant added is too large, the gain is not obvious compared with the iron removal effect when the amount of oxidant added is 20 mL / L. If the amount of oxidant added is too small, the iron removal effect is not significant.

[0099] Comparing Example 1 and Comparative Examples 1-3, it can be seen that in the impurity removal and recovery method described in this application, barium carbonate achieves better lead removal effect in a lower pH range, therefore it is added before pH adjustment; while polyferric sulfate has a better arsenic removal effect under conditions closer to neutral, therefore it is added after pH adjustment; finally, hydrogen peroxide is added to remove iron to provide sufficient reaction time for arsenic and iron removal, because the hydrolysis of polyferric sulfate still requires a certain amount of time, so adding hydrogen peroxide first and then adding polyferric sulfate will result in less than ideal arsenic and iron removal effects. The impurity removal and recovery method for electrowinning nickel anolyte described in this application, through the reasonable allocation of each step, sequentially performs lead precipitation, arsenic precipitation, and iron precipitation on the electrowinning nickel anolyte, which can achieve timely and efficient removal of lead, arsenic, and iron impurities in the electrowinning nickel anolyte, greatly shortening the impurity removal time, ensuring timely supply of electrowinning solution, ensuring the smooth progress of the electrowinning reaction, and avoiding capacity reduction due to the impurity removal process.

[0100] The applicant declares that the above description is only a specific implementation of this application, but the protection scope of this application is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application fall within the protection and disclosure scope of this application.

Claims

1. A method for removing impurities and recovering nickel anolyte by electrowinning, comprising the following steps: (1) Take the first electrolytic nickel anolyte and mix it with liquid alkali, and then perform a first solid-liquid separation treatment to obtain nickel hydroxide and filtrate. Evaporate the filtrate to obtain sodium sulfate; take the second electrolytic nickel anolyte and mix it with a nickel source to obtain a mixed solution; (2) Mix the mixed solution obtained in step (1) with barium salt and perform lead removal treatment; (3) After adjusting the pH of the material obtained after lead removal treatment in step (2) with nickel hydroxide obtained in step (1), the arsenic removal solution is obtained. The arsenic removal solution is then mixed with polyferric sulfate for arsenic removal treatment. (4) The material obtained after the arsenic removal treatment in step (3) is mixed with an oxidant to obtain an iron removal solution. The iron removal solution is subjected to a second solid-liquid separation treatment to obtain a catholyte containing lead, arsenic and iron and iron-containing slag. Sodium sulfate obtained in step (1) is added to the catholyte containing lead, arsenic and iron and reused in the nickel electrowinning process.

2. The impurity removal recovery process of claim 1, wherein, In step (1), the mass concentration of nickel ions in the first and second electrolytic nickel anolytes is independently 75 g / L to 85 g / L.

3. The impurity removal recovery method according to claim 1 or 2, wherein, In step (1), the mass concentration of sodium sulfate in the first and second electrolytic nickel anolytes is independently 80 g / L to 100 g / L.

4. The impurity removal recovery process of any one of claims 1-3, wherein, Step (1) The pH of the first electrolytic nickel anolyte and the second electrolytic nickel anolyte are each independently 0 to 1.

5.

5. The impurity removal recovery process of any one of claims 1-4, wherein, The mass concentration of the liquid alkali in step (1) is 30% to 42%; Optionally, the molar ratio of sodium hydroxide in the liquid alkali in step (1) to nickel ions in the first electrolytic nickel anolyte is (2-2.2):

1.

6. The impurity removal recovery process of any one of claims 1-5, wherein, The nickel source in step (1) includes nickel sulfate crystals and / or nickel sulfate solution; Optionally, the mass concentration of nickel ions in the nickel sulfate solution in step (1) is 100 g / L to 105 g / L; Optionally, the pH of the nickel sulfate solution in step (1) is 3.5 to 4.5; Optionally, the mass concentration of nickel ions in the mixed solution in step (1) is 80 g / L to 90 g / L; Optionally, the mass concentration of sodium sulfate in the mixed solution in step (1) is 60 g / L to 85 g / L; Optionally, the pH of the mixed solution in step (1) is 0 to 2.

7. The impurity removal recovery process of any one of claims 1-6, wherein, The barium salt mentioned in step (2) includes barium carbonate; Optionally, the mass-to-volume ratio of the barium salt to the mixed solution is 0.1 g / L to 0.4 g / L.

8. The impurity removal recovery process of any one of claims 1-7, wherein, The first stirring is performed during the lead removal process described in step (2); Optionally, the first stirring time is 20 min to 40 min; Optionally, the temperature of the lead removal process in step (2) is 50℃~70℃.

9. The impurity removal recovery process of any one of claims 1-8, wherein, The pH value in step (3) is 3.5–4.5; Optionally, the mass concentration of nickel ions in the arsenic removal solution in step (3) is 100 g / L to 105 g / L; Optionally, the mass-to-volume ratio of the polyferric sulfate to the arsenic removal solution in step (3) is 0.3 g / L to 0.6 g / L.

10. The impurity removal recovery process of any one of claims 1-9, wherein, A second stirring is performed during the arsenic removal process described in step (3); Optionally, the second stirring time is 20 min to 40 min; Optionally, the temperature of the arsenic removal treatment in step (3) is 50℃~70℃.

11. The impurity removal recovery process of any one of claims 1-10, wherein, The oxidant in step (4) comprises a hydrogen peroxide solution; Optionally, the volume ratio of the oxidant to the material obtained after the arsenic removal treatment in step (4) is 10 mL / L to 20 mL / L. Optionally, the mass concentration of the hydrogen peroxide solution is 30% to 42%.

12. The impurity removal recovery process of any one of claims 1-11, wherein, The mass / volume ratio of the sodium sulfate to the cathode solution after the removal of lead, arsenic and iron in step (4) is 80 g / L to 100 g / L.

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