Method for removing iron and cobalt from liquid chlorine after copper removal through nickel electrolysis

Abstract

The invention discloses a method for removing iron and cobalt from nickel electrolytic copper-removed liquid through chlorine, which comprises the following steps: S1, pH adjustment stage: introducing a nickel carbonate solution into the nickel electrolytic copper-removed liquid to adjust the pH to 4.6-4.9, and the nickel carbonate reaction time is less than or equal to 5 minutes; s2, chlorine ferric cobalt oxide stage: introducing chlorine into the solution prepared in the step S1; s3, an iron-cobalt co-precipitation stage: a sodium carbonate solution is introduced into the solution prepared in the step S2 to precipitate iron and cobalt, the reaction time of sodium carbonate is 10-30 min, and the pH value of the reaction end point is 4.8-5.0; and S4, a filtering stage: pumping the mixed solution prepared in the step S3 into a filtering device through a pump, and carrying out solid-liquid separation. According to the method, traditional segmented treatment of iron and cobalt is combined into one step, segmented adjustment of pH and oxidation-reduction potential is not needed to achieve iron removal and cobalt removal, the solution purification process is shortened, and the purification time cost and the energy consumption cost are saved.

Description

Technical Field

[0001] The invention relates to the technical field of nickel electrolytic purification methods, and in particular to a method for removing iron and cobalt with liquid chlorine gas after nickel electrolysis to remove copper. Background Art

[0002] In the production of electro-nickel, the purification process of nickel electrolytic solution determines the quality of electro-nickel production. At present, enterprises remove impurities through three-stage purification processes of iron removal, copper removal and cobalt removal. Iron removal adopts hydrolysis and iron removal, and the iron in the solution is oxidized by heating, ventilation and adding alkaline reagents to form iron hydroxide or iron-vanadium slag to remove the iron. Cobalt removal adopts chlorine oxidation to remove cobalt or extraction to remove cobalt, and the solution required for the electrolysis process is obtained after filtration. The process is long, the production process control is unstable, the acid and alkali consumption is too large, and the amount of slag produced is large, resulting in large nickel losses. And the existing iron-cobalt co-precipitation process still removes iron and cobalt respectively by controlling different pH and oxidation potentials. Therefore, there is an urgent need for a method to efficiently remove iron and cobalt, shorten the process flow, and reduce nickel losses. Summary of the invention

[0003] In view of the above technical problems, the present invention provides a method for removing iron and cobalt by liquid chlorine gas after copper removal by nickel electrolysis.

[0004] In order to achieve the above object, the technical solution of the present invention is as follows: A method for removing iron and cobalt by liquid chlorine gas after nickel electrolysis and copper removal, comprising the following steps: S1, pH adjustment stage: Add nickel carbonate solution to the nickel electrolytic copper removal solution to adjust the pH to 4.6-4.9, and the nickel carbonate reaction time is ≤5min; S2, chlorine oxidation of iron and cobalt stage: chlorine is introduced into the solution prepared in step S1, the chlorine oxidation end point ORP is 1065-1070 mV, and the chlorine oxidation time is controlled at 22-25 min; S3, iron-cobalt co-precipitation stage: sodium carbonate solution is introduced into the solution prepared in step S2 to precipitate iron-cobalt, wherein the sodium carbonate reaction time is 10-30 min, and the reaction end point pH is 4.8-5.0; S4, filtration stage: the mixed solution prepared in step S3 is pumped into a filtration device for solid-liquid separation.

[0005] Wherein, in step S1, the chemical composition of the solution after nickel electrolysis and copper removal is 64-71 g / L nickel, 0.1-0.3 g / L cobalt, 0.0003-0.0008 g / L copper, 0.2-0.5 g / L iron, 0.0003-0.0006 g / L lead, 0.0002-0.0005 g / L zinc, and 0.0001-0.002 g / L arsenic.

[0006] Wherein, the reaction temperature of steps S1 to S4 is 60-70°C.

[0007] Wherein, in step S4, the solution composition for removing iron and cobalt is Co≤0.01 g / L, Cu≤0.002 g / L, Fe≤0.0004 g / L, Pb≤0.0002 g / L, Zn≤0.0002 g / L, and As≤0.0002 g / L.

[0008] The beneficial effects of the present invention are as follows: the present invention adds nickel carbonate solution, chlorine gas and sodium carbonate solution to the solution after copper removal by nickel electrolysis, so as to precipitate iron and cobalt in the solution. The method combines the traditional segmented treatment of iron and cobalt into one step, and does not require segmented adjustment of pH and redox potential to achieve iron and cobalt removal, shortening the solution purification process, saving purification time cost and energy consumption cost. The present invention combines the traditional segmented treatment of iron and cobalt into one step, and does not require segmented adjustment of pH and redox potential to achieve iron and cobalt removal, shortening the solution purification process, saving purification time cost and energy consumption cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 The invention is a process flow chart. DETAILED DESCRIPTION

[0010] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present invention. In addition, in the following description, the description of known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0011] Example 1 like Figure 1 As shown, a method for removing iron and cobalt by liquid chlorine gas after nickel electrolysis and copper removal comprises the following steps: 1) pH adjustment stage: nickel carbonate solution was introduced into the copper removal solution to adjust the pH. The adjusted pH was 4.71. The nickel carbonate reaction time was 5 min and the reaction temperature was 60 °C. The chemical composition of the copper removal solution was 65.95 g / L nickel, 0.18 g / L cobalt, 0.00078 g / L copper, 0.33 g / L iron, 0.0004 g / L lead, 0.00024 g / L zinc and 0.00014 g / L arsenic. 2) Chlorine oxidation of iron and cobalt stage: chlorine is introduced into the solution prepared in step 1), the chlorine oxidation endpoint ORP is 1066 mV, the chlorine oxidation time is controlled at 24 min, and the reaction temperature is 61.5°C; 3) Iron-cobalt co-precipitation stage: sodium carbonate solution is introduced into the solution prepared in step 2) to precipitate iron and cobalt. The sodium carbonate reaction time is 20 min, the reaction end point pH is 4.87, and the reaction temperature is 62.2°C.

[0012] 4) Filtration stage: The mixed solution prepared in step 3) is pumped into a filtration device for solid-liquid separation. The solution composition after iron and cobalt removal is 64.45 g / L nickel, 0.0045 g / L cobalt, 0.00005 g / L copper, 0.0004 g / L iron, 0.00014 g / L lead, 0.00016 g / L zinc, and 0.00016 g / L arsenic.

[0013] Example 2 like Figure 1 As shown, a method for removing iron and cobalt by liquid chlorine gas after nickel electrolysis and copper removal comprises the following steps: 1) pH adjustment stage: nickel carbonate solution was introduced into the copper removal solution to adjust the pH. The adjusted pH was 4.64. The nickel carbonate reaction time was 5 min and the reaction temperature was 61.5 °C. The chemical composition of the copper removal solution was 69.54 g / L nickel, 0.21 g / L cobalt, 0.00034 g / L copper, 0.33 g / L iron, 0.00035 g / L lead, 0.0004 g / L zinc and 0.0011 g / L arsenic. 2) Chlorine oxidation of iron and cobalt stage: chlorine is introduced into the solution prepared in step 1), the chlorine oxidation endpoint ORP is 1065 mV, the chlorine oxidation time is controlled at 23 min, and the reaction temperature is 63°C; 3) Iron-cobalt co-precipitation stage: sodium carbonate solution is introduced into the solution prepared in step 2) to precipitate iron and cobalt. The sodium carbonate reaction time is 20 min, the reaction end point pH is 4.82, and the reaction temperature is 63.5°C.

[0014] 4) Filtration stage: The mixed solution prepared in step 3) is pumped into a filtration device for solid-liquid separation. The solution composition after iron and cobalt removal is 64.68 g / L nickel, 0.0092 g / L cobalt, 0.0006 g / L copper, 0.0004 g / L iron, 0.000095 g / L lead, 0.0002 g / L zinc, and 0.00018 g / L arsenic.

[0015] Example 3 like Figure 1 As shown, a method for removing iron and cobalt by liquid chlorine gas after nickel electrolysis and copper removal comprises the following steps: S1, pH adjustment stage: nickel carbonate solution is introduced into the nickel electrolytic copper removal solution to adjust the pH to 4.6, and the nickel carbonate reaction time is 5 minutes; S2, chlorine oxidation of iron and cobalt stage: chlorine is introduced into the solution prepared in step S1, the chlorine oxidation end point ORP is 1065mV, and the chlorine oxidation time is controlled at 22 min; S3, iron-cobalt co-precipitation stage: sodium carbonate solution is introduced into the solution prepared in step S2 to precipitate iron and cobalt, wherein the sodium carbonate reaction time is 10 min and the reaction end point pH is 4.8; S4, filtration stage: the mixed solution prepared in step S3 is pumped into a filtration device for solid-liquid separation.

[0016] Wherein, in step S1, the chemical composition of the solution after nickel electrolysis and copper removal is 64 g / L nickel, 0.1 g / L cobalt, 0.0003 g / L copper, 0.2 g / L iron, 0.0003 g / L lead, 0.0002 g / L zinc, and 0.0001 g / L arsenic.

[0017] Wherein, the reaction temperature of steps S1 to S4 is all 60°C.

[0018] Wherein, in step S4, the solution composition for removing iron and cobalt is Co≤0.01 g / L, Cu≤0.002 g / L, Fe≤0.0004 g / L, Pb≤0.0002 g / L, Zn≤0.0002 g / L, and As≤0.0002 g / L.

[0019] Example 4 like Figure 1 As shown, a method for removing iron and cobalt by liquid chlorine gas after nickel electrolysis and copper removal comprises the following steps: S1, pH adjustment stage: nickel carbonate solution is introduced into the nickel electrolytic copper removal solution to adjust the pH to 4.9, and the nickel carbonate reaction time is 5 minutes; S2, chlorine oxidation of iron and cobalt stage: chlorine is introduced into the solution prepared in step S1, the chlorine oxidation end point ORP is 1070 mV, and the chlorine oxidation time is controlled at 25 min; S3, iron-cobalt co-precipitation stage: sodium carbonate solution is introduced into the solution prepared in step S2 to precipitate iron and cobalt, wherein the sodium carbonate reaction time is 30 min and the reaction end point pH is 5.0; S4, filtration stage: the mixed solution prepared in step S3 is pumped into a filtration device for solid-liquid separation.

[0020] Wherein, in step S1, the chemical composition of the solution after nickel electrolysis and copper removal is 71 g / L nickel, 0.3 g / L cobalt, 0.0008 g / L copper, 0.5 g / L iron, 0.0006 g / L lead, 0.0005 g / L zinc, and 0.002 g / L arsenic.

[0021] Wherein, the reaction temperature of steps S1 to S4 is 70°C.

[0022] Wherein, in step S4, the solution composition for removing iron and cobalt is Co≤0.01 g / L, Cu≤0.002 g / L, Fe≤0.0004 g / L, Pb≤0.0002 g / L, Zn≤0.0002 g / L, and As≤0.0002 g / L.

[0023] Example 5 like Figure 1 As shown, a method for removing iron and cobalt by liquid chlorine gas after nickel electrolysis and copper removal comprises the following steps: 1) pH adjustment stage: The pH of the solution after copper removal by nickel electrolysis was adjusted to 4.67 by passing nickel carbonate solution. The reaction time of nickel carbonate was 5 min and the reaction temperature was 62°C. The chemical composition of the solution after copper removal was 70.25 g / L nickel, 0.18 g / L cobalt, 0.00047 g / L copper, 0.35 g / L iron, 0.00058 g / L lead, 0.00049 g / L zinc and 0.00019 g / L arsenic. 2) Chlorine oxidation of iron and cobalt stage: chlorine is introduced into the solution prepared in step S1, the chlorine oxidation endpoint ORP is 1065mV, the chlorine oxidation time is controlled at 24 min, and the reaction temperature is 63.2°C; 3) Iron-cobalt co-precipitation stage: sodium carbonate solution is introduced into the solution prepared in step S2 to precipitate iron and cobalt, wherein the sodium carbonate reaction time is 20 min, the reaction end point pH is 4.86, and the reaction temperature is 64°C; 4) Filtration stage: The mixed solution prepared in step S3 is pumped into a filtration device for solid-liquid separation. The solution composition for removing iron and cobalt is 64.60 g / L nickel, 0.0048 g / L cobalt, 0.0004 g / L copper, 0.0004 g / L iron, 0.000098 g / L lead, 0.00016 g / L zinc, and 0.00018 g / L arsenic.

[0024] Example 6 like Figure 1 As shown, a method for removing iron and cobalt by liquid chlorine gas after nickel electrolysis and copper removal comprises the following steps: 1) pH adjustment stage: The pH of the solution after nickel electrolysis copper removal was adjusted to 4.57 by passing nickel carbonate solution, the nickel carbonate reaction time was 5 min, the reaction temperature was 63.2°C, and the chemical composition of the solution after copper removal was 68.58 g / L nickel, 0.19 g / L cobalt, 0.00055 g / L copper, 0.34 g / L iron, 0.00044 g / L lead, 0.00038 g / L zinc, and 0.00048 g / L arsenic; 2) Chlorine oxidation of iron and cobalt stage: chlorine is introduced into the solution prepared in step S1, the chlorine oxidation endpoint ORP is 1070 mV, the chlorine oxidation time is controlled at 23 min, and the reaction temperature is 63°C; 3) Iron-cobalt co-precipitation stage: sodium carbonate solution is introduced into the solution prepared in step S2 to precipitate iron and cobalt, wherein the sodium carbonate reaction time is 22 min, the reaction end point pH is 4.82, and the reaction temperature is 64°C; 4) Filtration stage: The mixed solution prepared in step S3 is pumped into a filtration device for solid-liquid separation. The solution composition after iron and cobalt removal is 64.33 g / L nickel, 0.009 g / L cobalt, 0.0009 g / L copper, 0.0004 g / L iron, 0.00012 g / L lead, 0.00019 g / L zinc, and 0.00018 g / L arsenic.

[0025] It should be understood that the above specific embodiments of the present invention are only used to illustrate or explain the principles of the present invention, and do not constitute a limitation of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made without departing from the spirit and scope of the present invention should be included in the protection scope of the present invention. In addition, the appended claims of the present invention are intended to cover all changes and modifications that fall within the scope and boundaries of the appended claims, or the equivalent forms of such scope and boundaries.

Claims

1. A method for removing iron and cobalt by liquid chlorine after electrolytic copper removal by nickel, characterized in that: The following steps are involved: S1, pH adjustment stage: Add nickel carbonate solution to the nickel electrolytic copper removal solution to adjust the pH to 4.6-4.9, and the nickel carbonate reaction time is ≤5min; S2, chlorine oxidation of iron and cobalt stage: chlorine is introduced into the solution prepared in step S1, the chlorine oxidation end point ORP is 1065-1070 mV, and the chlorine oxidation time is controlled at 22-25 min; S3, iron-cobalt co-precipitation stage: sodium carbonate solution is introduced into the solution prepared in step S2 to precipitate iron-cobalt, wherein the sodium carbonate reaction time is 10-30 min, and the reaction end point pH is 4.8-5.0; S4, filtration stage: the mixed solution prepared in step S3 is pumped into a filtration device for solid-liquid separation.

2. The method for removing iron and cobalt by liquid chlorine gas after electrolytic copper removal by nickel according to claim 1, characterized in that: In step S1, the chemical composition of the solution after nickel electrolysis and copper removal is 64-71 g / L nickel, 0.1-0.3 g / L cobalt, 0.0003-0.0008 g / L copper, 0.2-0.5 g / L iron, 0.0003-0.0006 g / L lead, 0.0002-0.0005 g / L zinc, and 0.0001-0.002 g / L arsenic.

3. The method for removing iron and cobalt by liquid chlorine gas after electrolytic copper removal by nickel according to claim 1, characterized in that: The reaction temperature of steps S1 to S4 is 60-70°C.

4. The method for removing iron and cobalt by liquid chlorine gas after electrolytic copper removal by nickel according to claim 1, characterized in that: In step S4, the solution composition for removing iron and cobalt is Co≤0.01 g / L, Cu≤0.002 g / L, Fe≤0.0004 g / L, Pb≤0.0002 g / L, Zn≤0.0002 g / L, and As≤0.0002 g / L.

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