A process for the production of nickel by chloridizing electrodeposition

Abstract

The present application relates to the field of hydrometallurgy, and particularly relates to a production method of chlorination electrowinning nickel to solve the problems of long production process, high production cost, limitation of purification and electrolysis process, bottleneck of product quality improvement, and the influence on the demand of high-quality electrowinning nickel in the fields of aerospace, high-end battery and high-temperature alloy in the prior art. The production method of electrowinning nickel takes nickel concentrate as raw material, and through processes such as nickel concentrate slurry, displacement leaching, iron removal, copper removal, solvent extraction, lead removal, electrowinning and chlorine recovery, the method has the characteristics of low processing cost, high product quality, recyclable chlorine and environmental friendliness, and produces electrowinning nickel containing 99.99% of nickel, which meets the demand of high-quality electrowinning nickel in the fields of aerospace, high-end plating and the like.

Description

Technical Field

[0001] This invention relates to the field of hydrometallurgical technology, specifically to a method for producing nickel by electrowinning with chloride. Background Technology

[0002] The current nickel market is experiencing increasingly diversified product demands, with manufacturers continuously striving to meet the personalized needs of niche markets such as aerospace, electroplating, batteries, and traditional stainless steel. Traditional nickel sulfide production employs a three-stage purification and soluble anode diaphragm electrolysis process. Solution purification primarily relies on chemical precipitation for impurity removal. Existing technologies cannot meet the requirements for producing high-quality electrolytic nickel, and electrolytic nickel products fail to satisfy the quality demands of aerospace, high-end batteries, and high-temperature alloys. Furthermore, traditional electrolytic nickel production suffers from lengthy processes, high production costs, and limitations imposed by purification and electrolysis processes, hindering product quality improvement. Therefore, a new electrolytic nickel production method is needed that offers low processing costs, high product quality, recyclability, and environmental friendliness to address the problems inherent in traditional electrolytic nickel production. Summary of the Invention

[0003] This invention provides a method for producing electrolytic nickel chloride to solve the problems mentioned above.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: A method for producing electrolytic nickel chloride includes the following steps: Step 1: Using nickel concentrate as raw material, slurry is prepared by adding dechlorinated anolyte and nickel concentrate to a mechanically stirred slurry tank. The liquid-to-solid ratio is 3-4:1. The nickel concentrate has a particle size of -280 mesh and a particle size greater than 90%. The mixture is slurryed together and stirred for 30 minutes.

[0005] Step 2: The displacement leaching is a two-stage continuous leaching process. The first stage leaching has an oxidation-reduction potential of 400-450 mV and a temperature of 90-115℃. The second stage leaching has an oxidation-reduction potential of 450-520 mV and a temperature of 90-105℃. The reaction time is 4 hours. The displacement leaching solution enters the iron removal process, producing the pre-iron removal solution. The displacement residue enters the leaching process. The leaching solution requires a nickel ion concentration >200 g / L and a chloride ion concentration >260 g / L.

[0006] Step 3: Use 16 g / L NaClO3 as an oxidant, adding 0.2 times the volume of the liquid before iron removal, controlling the pH at 2.5-3.0, and reacting for 4 hours. The resulting liquid after iron removal is then subjected to solvent extraction. Because the leachate is a chloride system with a low sulfate content, the pyrite method only produces a small amount of pyrite slag, with most of the iron forming ferric hydroxide colloid. This results in poor slag filtration performance and high nickel content. The hematite method for iron removal requires high-pressure equipment, leading to high investment costs. The goethite method was chosen because the pyrite contains Fe... 3+The content is less than 1g / L, and the iron in the nickel concentrate leaching solution is mainly in the form of Fe. 2+ In the form of iron removal, goethite removal shows better advantages.

[0007] Step 4: Chlorine leaching. After the leaching residue from step 2 is slurried with copper slag, chlorine recovered from electrowinning and the obtained copper slag slurry are added to the leaching tank. The leaching potential is controlled at 400-450mV and the temperature at 90-115℃. Continuous leaching is carried out to achieve a three-phase reaction of gas, liquid, and solid. The copper leaching solution enters the copper electrowinning process to produce copper powder, and the copper leaching residue enters the precious metal enrichment process. The chlorine-containing waste gas is absorbed by alkaline solution and discharged in compliance with standards.

[0008] Step 5: Extract the iron-removed liquid from Step 3 using a combined P204 and N235 extraction method. The pre-extraction solution should have a pH of 3.5-4.0 and a temperature of 40-50℃. During the N235 nickel-cobalt separation process, the N235 extractant ratio is (20-30)% N235 + (20-10)15% isooctanol + 60% light white oil, with a 1:1 ratio of N235 extractant to the iron-removed liquid. Acidify the iron-removed liquid with 5 mol / L hydrochloric acid. The Cl content in the iron-removed liquid... - Concentration ≥270g / L.

[0009] The principle of P204 extraction of impurity ions is that the order in which metal ions can transfer from aqueous solution to organic phase is consistent with the order in which they hydrolyze. P204 has different extraction equilibrium pH values ​​for various metal cations, so metal separation can be achieved by controlling different pH values. Under certain conditions, the greater the difference in extraction equilibrium pH values ​​between two metals, the easier they are to separate.

[0010] N235 can extract complex anions formed with chloride ions in chloride solutions, but it does not extract cations. Furthermore, the resulting extracts have low solubility in the organic phase, easily forming a third phase and reducing the extraction yield of metal ions. Therefore, isooctanol, a modifier, must be added, with light white oil as a diluent. During N235 extraction, acidification with hydrochloric acid should be performed first, followed by extraction of the metal complex anions. The metal extraction effect of N235 gradually increases with increasing chloride ion concentration in the solution.

[0011] Step 6: The raffinate from Step 5 is oxidized with recovered chlorine to remove lead. The reaction temperature is 60-80℃, the reaction time is 2.5h, the oxidation-reduction potential is (1000-1050) mV, and the pH of the raffinate is 3.5-4.0. This further removes impurities such as copper, iron, cobalt, and manganese. Pb is then removed using chlorine. 2+ Oxidation to Pb 4+ Lead dioxide precipitates out, and nickel carbonate is added during the process to neutralize the acid produced in the reaction, causing Pb to... 2 ++Cl 2+2NiCO3=PbO2↓+2Ni 2 ++2Cl – The reaction +2CO2↑ continues in the forward direction.

[0012] Step 7: Mix the lead-removed solution obtained in Step 6 with the evaporated dechlorination anolyte, and then perform electrowinning in an electrowinning cell. Control the pH value to be 1.0-2.5 and the current density to be 250-330 A / m². Electrowinning produces electrowinning nickel containing 99.99% nickel. The overflow anolyte from the electrowinning cell and the gas-liquid mixture in the anode cover are then subjected to evaporation dechlorination.

[0013] Furthermore, the mixture of chlorine gas generated by the titanium-coated ruthenium anode reaction in step 7 and the anolyte, along with the anolyte from the electrowinning cell, is heated to 80°C via a plate heat exchanger and then enters a high-efficiency vacuum evaporation dechlorination unit to achieve evaporation concentration and dechlorination of the anolyte. After one evaporation and dechlorination, the chlorine content in the anolyte is less than 20 mg / L, and after the second dechlorination, the chlorine content in the anolyte is less than 5 mg / L. The chlorine gas is recovered and reused in processes such as chlorine leaching and chlorine oxidation to remove lead, achieving recycling.

[0014] The present invention has the following beneficial effects: This invention provides a method for producing high-quality electrolytic nickel with a nickel content of 99.99% through processes such as slurrying, leaching, copper precipitation, iron removal, solvent extraction, lead removal, electrowinning, and chlorine recovery. This method features low processing costs, high product quality, recyclability, and environmental friendliness. It effectively addresses the problems of lengthy traditional electrolytic nickel production processes, high production costs, and limitations imposed by purification and electrolysis processes, which hinder product quality improvement and thus affect the demand for high-quality electrolytic nickel in aerospace, high-end batteries, and high-temperature alloys. Attached Figure Description

[0015] Figure 1 This is a flowchart of the nickel chloride electrowinning production method in this invention. Detailed Implementation

[0016] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0017] like Figure 1 As shown, a method for producing electrolytic nickel chloride includes the following process: Step 1: Using nickel concentrate as raw material, slurry is prepared by adding dechlorinated anolyte and nickel concentrate to a mechanically stirred slurry tank with a liquid-to-solid ratio of 3-4:1. The nickel concentrate has a particle size of -280 mesh and a particle size greater than 90%. The mixture is slurryed together and stirred for 30 minutes. The main chemical composition of the nickel concentrate is shown in Table 1.

[0018] Table 1 Step 2: The displacement leaching is a two-stage continuous leaching process. The first stage leaching has an oxidation-reduction potential of 400-450mV and a temperature of 90-115℃. The second stage leaching has an oxidation-reduction potential of 450-520mV and a temperature of 90-105℃. The reaction time is 4 hours. The displacement leaching solution enters the iron removal process, producing the pre-iron removal solution. The displacement residue enters the chlorine leaching process.

[0019] Step 3: Use 16 g / L NaClO3 as an oxidant, add 0.2 times the volume of the liquid before iron removal, control the pH at 2.5-3.0, and react for 4 hours to obtain the liquid after iron removal.

[0020] Step 4: After the leaching residue from step 2 is slurried with copper slag, chlorine gas and copper slag slurry are added to the leaching tank. The leaching potential is controlled at 400-450mV and the temperature at 90-115℃. Continuous leaching is carried out to achieve a gas-liquid-solid three-phase reaction.

[0021] Step 5: Extract the iron-removed liquid from Step 3 using a combined P204 and N235 extraction method. The pre-extraction solution should have a pH of 3.5-4.0 and a temperature of 40-50℃. During the N235 nickel-cobalt separation process, the N235 extractant ratio is (20-30)% N235 + (20-10)% isooctanol + 60% light white oil, with a 1:1 ratio between the N235 extractant and the iron-removed liquid. Acidify the iron-removed liquid with 5 mol / L hydrochloric acid. The Cl content in the iron-removed liquid... - Concentration ≥270g / L.

[0022] Step 6: Oxidize the raffinate from Step 5 with chlorine to remove lead. The reaction temperature is 60-80℃, the reaction time is 2.5h, the oxidation-reduction potential is (1000-1050)mV, and the pH of the raffinate is 3.5-4.0 to further remove impurities.

[0023] Step 7: Mix the lead-removed solution obtained in Step 6 with the anolyte and perform electrowinning in an electrowinning cell. Control the pH value to be 1.0-2.5 and the current density to be 250-330 A / m². Electrowinning produces electrowinning nickel containing 99.99% nickel. The overflow anolyte from the electrowinning cell and the gas-liquid mixture in the anode cover are subjected to evaporative dechlorination treatment.

[0024] Furthermore, the mixture of chlorine gas and anolyte generated by the titanium-coated ruthenium anode reaction in step 7, along with the anolyte from the electrodeposition cell, is heated to 80°C via a plate heat exchanger and then fed into a high-efficiency vacuum evaporation dechlorinator to achieve evaporation, concentration, and dechlorination of the anolyte. After dechlorination, the anolyte contains less than 5 mg / L of chlorine.

[0025] Example 1 The following process is used in the production of electrolytic nickel via the chloride process: Step 1: Using nickel concentrate as raw material, slurry is prepared by adding dechlorinated anolyte and nickel concentrate to a mechanically stirred slurry tank. The liquid-to-solid ratio is 3.5:1. The nickel concentrate has a particle size of -280 mesh and a particle size greater than 90%. The mixture is slurryed together and stirred for 30 minutes.

[0026] Step 2: The displacement leaching is a two-stage continuous leaching process. The first stage leaching has an oxidation-reduction potential of 425 mV and a temperature of 105 ℃, while the second stage leaching has an oxidation-reduction potential of 490 mV and a temperature of 95 ℃. The reaction time is 4 h. The displacement leaching solution enters the iron removal stage, and the displacement residue enters the chlorine leaching stage.

[0027] Step 3: Use 16 g / L NaClO3 as an oxidant, add it in a volume that is 0.2 times the volume of the liquid before iron removal, control the pH at 2.7, and react for 4 hours to obtain the liquid after iron removal.

[0028] Step 4: After the leaching residue from step 2 is slurried with copper slag, chlorine gas and the obtained slurry are added to the leaching tank. The leaching potential is controlled at 425mV and the temperature at 105℃, and leaching is carried out continuously to allow the gas, liquid and solid three-phase reaction to occur. The chemical composition of the obtained nickel leaching solution is shown in Table 2.

[0029] Table 2 Step 5: Extract the iron-removed liquid from Step 3 using a combination of P204 and N235 extraction. The pre-extraction liquid has a pH of 3.8 and a temperature of 45℃. During the N235 nickel-cobalt separation process, the N235 extractant ratio is N235 (20%) + isooctanol 20% + light white oil 60%, and the N235 extractant to iron-removed liquid flow ratio is 1:1. The iron-removed liquid is acidified with 5 mol / L hydrochloric acid. The Cl in the iron-removed liquid... - Concentration ≥270g / L.

[0030] Step 6: The extract from Step 5 is oxidized with chlorine gas to remove lead. The reaction temperature is 75℃, the reaction time is 2.5h, the oxidation-reduction potential is 1000mV, and the pH of the extract is 3.9. Impurities such as copper, iron, cobalt, and manganese are further removed.

[0031] Step 7: After mixing the lead-removed solution obtained in Step 6 with the anolyte, perform electrowinning in an electrowinning cell, controlling the pH value to 2.0 and the current density to 290 A / m². Electrowinning produces electrowinning nickel containing 99.99% nickel. The overflow anolyte from the electrowinning cell and the gas-liquid mixture in the anode cover are subjected to dechlorination treatment. After extraction and lead removal, the liquid phase obtained has a Ni ion concentration of 225.06 g / L and a Pb ion concentration of 0.000095 g / L, with an extraction rate of 2.53% and a lead removal rate of 99.6%. The composition of the obtained new electrowinning solution is shown in Table 3.

[0032] Table 3 Furthermore, the mixture of chlorine gas and anolyte generated by the titanium-coated ruthenium anode reaction in step 7, along with the anolyte from the electrodeposition cell, is heated to 80°C via a plate heat exchanger and then fed into a high-efficiency vacuum evaporation dechlorinator to achieve evaporation, concentration, and dechlorination of the anolyte. After dechlorination, the anolyte contains less than 5 mg / L of chlorine.

[0033] Example 2 The following process is used in the production of electrolytic nickel via the chloride process: Step 1: Using nickel concentrate as raw material, slurry is prepared by adding dechlorinated anolyte and nickel concentrate to a mechanically stirred slurry tank. The liquid-to-solid ratio is 3.5:1. The nickel concentrate has a particle size of -280 mesh and a particle size greater than 90%. The mixture is slurryed together and stirred for 30 minutes.

[0034] Step 2: The displacement leaching is a two-stage continuous leaching process. The first stage leaching has an oxidation-reduction potential of 425 mV and a temperature of 105 ℃, while the second stage leaching has an oxidation-reduction potential of 490 mV and a temperature of 95 ℃. The reaction time is 4 h. The displacement leaching solution enters the iron removal stage, and the displacement residue enters the chlorine leaching stage.

[0035] Step 3: Use 16 g / L NaClO3 as an oxidant, add it in a volume that is 0.2 times the volume of the liquid before iron removal, control the pH at 2.7, and react for 4 hours to obtain the liquid after iron removal.

[0036] Step 4: After the leaching residue from step 2 is slurried with copper slag, chlorine gas and the obtained slurry are added to the leaching tank. The leaching potential is controlled at 425mV and the temperature at 105℃, and leaching is carried out continuously to achieve a gas-liquid-solid three-phase reaction.

[0037] Step 5: Extract the iron-removed liquid from Step 3 using a combination of P204 and N235 extraction. The pre-extraction liquid has a pH of 3.8 and a temperature of 45℃. During the N235 nickel-cobalt separation process, the N235 extractant ratio is N235 (30)% + isooctanol 10% + light white oil 60%, and the N235 extractant to iron-removed liquid flow ratio is 1:1. The iron-removed liquid is acidified with 5mol / L hydrochloric acid. The Cl in the iron-removed liquid... - Concentration ≥270g / L.

[0038] Step 6: The extract from Step 5 is subjected to chlorine oxidation to remove lead. The reaction temperature is 75℃, the reaction time is 2.5h, the oxidation-reduction potential is 1050mV, and the pH of the extract is 3.9. Impurities such as copper, iron, cobalt, and manganese are further removed.

[0039] Step 7: The lead-removed solution obtained in Step 6 is mixed with the anolyte and then electrowinning is performed in an electrowinning cell. The pH value is controlled at 2.0 and the current density is 290 A / m². Electrowinning produces electrowinning nickel with a nickel content of 99.99%. The overflow anolyte from the electrowinning cell and the gas-liquid mixture in the anode cover are subjected to dechlorination treatment. After extraction and lead removal, the Ni ion concentration in the liquid phase is 229.52 g / L, the Pb ion concentration is 0.00009 g / L, the extraction rate is 2.36%, and the lead removal rate is 99.8%.

[0040] Furthermore, the mixture of chlorine gas and anolyte generated by the titanium-coated ruthenium anode reaction in step 7, along with the anolyte from the electrodeposition cell, is heated to 80°C via a plate heat exchanger and then fed into a high-efficiency vacuum evaporation dechlorinator to achieve evaporation, concentration, and dechlorination of the anolyte. After dechlorination, the anolyte contains less than 5 mg / L of chlorine.

[0041] Example 3 The following process is used in the production of electrolytic nickel via the chloride process: Step 1: Using nickel concentrate as raw material, slurry is prepared by adding dechlorinated anolyte and nickel concentrate to a mechanically stirred slurry tank. The liquid-to-solid ratio is 3.5:1. The nickel concentrate has a particle size of -280 mesh and a particle size greater than 90%. The mixture is slurryed together and stirred for 30 minutes.

[0042] Step 2: The displacement leaching is a two-stage continuous leaching process. The first stage leaching has an oxidation-reduction potential of 425 mV and a temperature of 105 ℃, while the second stage leaching has an oxidation-reduction potential of 490 mV and a temperature of 95 ℃. The reaction time is 4 h. The displacement leaching solution enters the iron removal stage, and the displacement residue enters the chlorine leaching stage.

[0043] Step 3: Use 16 g / L NaClO3 as an oxidant, add it in a volume that is 0.2 times the volume of the liquid before iron removal, control the pH at 2.7, and react for 4 hours to obtain the liquid after iron removal.

[0044] Step 4: After the leaching residue from step 2 is slurried with copper slag, chlorine gas and the obtained slurry are added to the leaching tank. The leaching potential is controlled at 425mV and the temperature at 105℃, and leaching is carried out continuously to achieve a gas-liquid-solid three-phase reaction.

[0045] Step 5: Extract the iron-removed liquid from Step 3 using a combination of P204 and N235 extraction. The pre-extraction liquid has a pH of 3.8 and a temperature of 45℃. During the N235 nickel-cobalt separation process, the N235 extractant ratio is N235 (25%) + isooctanol 15% + light white oil 60%, and the N235 extractant to iron-removed liquid flow ratio is 1:1. The iron-removed liquid is acidified with 5mol / L hydrochloric acid. The Cl in the iron-removed liquid... - Concentration ≥270g / L.

[0046] Step 6: The extract from Step 5 is oxidized with chlorine to remove lead. The reaction temperature is 75℃, the reaction time is 2.5h, the oxidation-reduction potential is 1025mV, and the pH of the extract is 3.9. Impurities such as copper, iron, cobalt, and manganese are further removed.

[0047] Step 7: The lead-removed solution obtained in Step 6 is mixed with the anolyte and then electrowinning is performed in an electrowinning cell. The pH value is controlled at 2.0 and the current density is 290 A / m². Electrowinning produces electrowinning nickel with a nickel content of 99.99%. The overflow anolyte from the electrowinning cell and the gas-liquid mixture in the anode cover are subjected to dechlorination treatment. After extraction and lead removal, the Ni ion concentration in the liquid phase is 231.83 g / L, the Pb ion concentration is 0.000086 g / L, the extraction rate is 2.06%, and the lead removal rate is 99.79%.

[0048] Furthermore, the mixture of chlorine gas and anolyte generated by the titanium-coated ruthenium anode reaction in step 7, along with the anolyte from the electrodeposition cell, is heated to 80°C via a plate heat exchanger and then fed into a high-efficiency vacuum evaporation dechlorinator to achieve evaporation, concentration, and dechlorination of the anolyte. After dechlorination, the anolyte contains less than 5 mg / L of chlorine.

[0049] Comparative Example 1 The following process is used in the production of electrolytic nickel via the chloride process: Step 1: Using nickel concentrate as raw material, slurry is prepared by adding dechlorinated anolyte and nickel concentrate to a mechanically stirred slurry tank. The liquid-to-solid ratio is 3.5:1. The nickel concentrate has a particle size of -280 mesh and a particle size greater than 90%. The mixture is slurryed together and stirred for 30 minutes.

[0050] Step 2: The displacement leaching is a two-stage continuous leaching process. The first stage leaching has an oxidation-reduction potential of 425 mV and a temperature of 105 ℃, while the second stage leaching has an oxidation-reduction potential of 490 mV and a temperature of 95 ℃. The reaction time is 4 h. The displacement leaching solution enters the iron removal stage, and the displacement residue enters the chlorine leaching stage.

[0051] Step 3: Use 16 g / L NaClO3 as an oxidant, add it in a volume that is 0.2 times the volume of the liquid before iron removal, control the pH at 2.7, and react for 4 hours to obtain the liquid after iron removal.

[0052] Step 4: After the leaching residue from step 2 is slurried with copper slag, chlorine gas and the obtained slurry are added to the leaching tank. The leaching potential is controlled at 425mV and the temperature at 105℃, and leaching is carried out continuously to achieve a gas-liquid-solid three-phase reaction.

[0053] Step 5: Extract the iron-removed liquid from Step 3 using a combination of P204 and N235 extraction. The pre-extraction liquid has a pH of 3.8 and a temperature of 45℃. During the N235 nickel-cobalt separation process, the N235 extractant ratio is N235 (35%) + isooctanol 5% + light white oil 60%, and the N235 extractant to iron-removed liquid flow ratio is 1:1. The iron-removed liquid is acidified with 5mol / L hydrochloric acid. The Cl in the iron-removed liquid... - Concentration ≥270g / L.

[0054] Step 6: The extract from Step 5 is subjected to chlorine oxidation to remove lead. The reaction temperature is 75℃, the reaction time is 2.5h, the oxidation-reduction potential is 1070mV, and the pH of the extract is 3.9. Impurities such as copper, iron, cobalt, and manganese are further removed.

[0055] Step 7: The lead-removed solution obtained in Step 6 is mixed with the anolyte and then electrowinning is performed in an electrowinning cell. The pH value is controlled at 2.0 and the current density is 290 A / m². Electrowinning produces electrowinning nickel with a nickel content of 99.99%. The overflow anolyte from the electrowinning cell and the gas-liquid mixture in the anode cover are subjected to dechlorination treatment. After extraction and lead removal, the Ni ion concentration in the liquid phase is 215.43 g / L, the Pb ion concentration is 0.00015 g / L, the extraction rate is 2.79%, and the lead removal rate is 99.81%.

[0056] Furthermore, the mixture of chlorine gas and anolyte generated by the titanium-coated ruthenium anode reaction in step 7, along with the anolyte from the electrodeposition cell, is heated to 80°C via a plate heat exchanger and then fed into a high-efficiency vacuum evaporation dechlorinator to achieve evaporation, concentration, and dechlorination of the anolyte. After dechlorination, the anolyte contains less than 5 mg / L of chlorine.

[0057] The electrolytic nickel prepared by the chlorination method has the chemical composition of Ni + Co, with a Ni mass fraction of not less than 99.99%, a Co mass fraction of not more than 0.005%, and impurity contents of Fe, Cu, Zn, and As not more than 0.002%, 0.0015%, 0.001%, and 0.0008%, respectively. Impurity contents of Cd, Sn, Sb, Pb, and Bi are all not more than 0.0003%.

Claims

1. A method for producing electrolytic nickel chloride, characterized in that, The process includes the following steps: Step 1: Using nickel concentrate as raw material, slurry is made by adding dechlorinated anolyte and nickel concentrate to a mechanically stirred slurry tank. The liquid-to-solid ratio is 3-4:

1. The nickel concentrate has a particle size of -280 mesh and a particle size greater than 90%. The mixture is slurryed together and stirred for 30 minutes. Step 2: The displacement leaching is a two-stage continuous leaching process. The first stage leaching has an oxidation-reduction potential of 400-450mV and a temperature of 90-115℃. The second stage leaching has an oxidation-reduction potential of 450-520mV and a temperature of 90-105℃. The reaction time is 4 hours. The displacement leaching solution enters the iron removal process to produce the iron removal pre-liquid. The displacement residue enters the chlorine leaching process. Step 3: Use 16 g / L NaClO3 as an oxidant, add 0.2 times the volume of the liquid before iron removal, control the pH at 2.5-3.0, and react for 4 hours to obtain the liquid after iron removal; Step 4: After the leaching residue from step 2 is slurried with copper slag, chlorine gas and copper slag slurry are added to the leaching tank. The leaching potential is controlled at 400-450mv and the temperature at 90-115℃. Continuous leaching is carried out to allow the gas, liquid and solid three-phase reaction to occur. Step 5: Extract the iron-removed liquid from Step 3 using a combined P204 and N235 extraction method. The pre-extraction solution should have a pH of 3.5-4.0 and a temperature of 40-50℃. During the N235 nickel-cobalt separation process, the N235 extractant ratio is (20-30)% N235 + (20-10)% isooctanol + 60% light white oil, with a 1:1 ratio between the N235 extractant and the iron-removed liquid. Acidify the iron-removed liquid with 5 mol / L hydrochloric acid. The Cl content in the iron-removed liquid... - Concentration ≥270g / L; Step 6: Oxidize the raffinate from Step 5 with chlorine gas to remove lead. The reaction temperature is 60-80℃, the reaction time is 2.5h, the oxidation-reduction potential is (1000-1050) mV, and the pH of the raffinate is 3.5-4.0 to further remove impurities. Step 7: Mix the lead-removed solution obtained in Step 6 with the anolyte and perform electrowinning in an electrowinning cell. Control the pH value to be 1.0-2.5 and the current density to be 250-330 A / m². Electrowinning produces electrowinning nickel containing 99.99% nickel. The overflow anolyte from the electrowinning cell and the gas-liquid mixture in the anode cover are subjected to evaporative dechlorination treatment.

2. The method for producing electrolytic nickel chloride according to claim 1, characterized in that: The mixture of chlorine gas and anolyte generated by the titanium-coated ruthenium anode reaction in step 7, along with the anolyte from the electrodeposition cell, is heated to 80°C via a plate heat exchanger and then enters a high-efficiency vacuum evaporation dechlorinator to achieve evaporation, concentration, and dechlorination of the anolyte. After dechlorination, the anolyte contains less than 5 mg / L of chlorine.

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