Method for intensively extracting and purifying 5N-grade high-purity cobalt and nickel by using ionic liquid

Abstract

The invention provides a method for intensively extracting and purifying 5N-grade high-purity cobalt and nickel through ionic liquid, and belongs to the technical field of non-ferrous metal separation and purification. According to the method, the specific ionic liquid is selected as the extraction medium, matched with the synergistic extraction agent and combined with the micro-channel reactor to achieve efficient mass transfer, the Co / Ni and Mn / Cu separation coefficient can be remarkably increased, the ionic liquid recovery rate is increased, the 5N-grade high-purity cobalt-nickel product is finally obtained, and the process is easy for large-scale continuous production and has a wide application prospect. The defects of poor Mn and Cu impurity separation selectivity, high solvent loss rate and low process efficiency in the existing Co / Ni paragenic ore extraction and purification process are overcome. And meanwhile, the impurity separation selectivity is remarkably improved, the solvent loss is reduced, the process is efficient and environmentally friendly, the method is suitable for large-scale industrial production of high-purity cobalt and nickel, and key raw material guarantee is provided for the fields of new energy, electronic information and the like. The result of the embodiment shows that the cobalt and the nickel obtained by the invention both meet the 5N-level requirement.

Description

Technical Field

[0001] This invention relates to the field of non-ferrous metal separation and purification technology, and in particular to a method for purifying 5N grade high-purity cobalt and nickel by ionic liquid-enhanced extraction. Background Technology

[0002] Cobalt and nickel, as important strategic non-ferrous metals, are widely used in new energy power batteries (such as lithium-ion battery cathode materials), aerospace high-temperature alloys, electronic information materials (such as precision resistors and connectors), and catalytic materials. With the rapid development of the new energy industry, the market demand for high-purity cobalt and nickel (especially 5N grade and above) has exploded. However, cobalt and nickel often exist in nature as symbiotic minerals (such as nickel-cobalt sulfide ores, and cobalt associated with laterite nickel ore), and these ores often contain impurities such as manganese and copper. The presence of these impurities can severely affect the performance of cobalt and nickel products. For example, in lithium-ion battery cathode materials, manganese and copper impurities can lead to decreased battery cycle life and capacity decay; in high-temperature alloys, impurities can reduce the alloy's strength and corrosion resistance. Therefore, the efficient separation and purification of cobalt and nickel from Co / Ni symbiotic ores, removing impurities such as manganese and copper, is a crucial step in the preparation of high-purity cobalt and nickel. Currently, the main industrial methods for separating and purifying cobalt and nickel from Co / Ni symbiotic ores include precipitation, ion exchange, and extraction. Among these, extraction is one of the most widely used processes due to its advantages such as high separation efficiency, good selectivity, and ease of large-scale continuous production. Traditional extraction processes often use organophosphorus extractants (such as P204 and P507) or carboxylic acid extractants, with kerosene or sulfonated kerosene as diluents to form the organic phase, which is then contacted with the Co / Ni-containing aqueous phase for extraction. However, traditional extraction processes have the following significant drawbacks when processing Co / Ni symbiotic ores: Poor selectivity for separating Mn and Cu impurities: Traditional organic extractants are less effective against Co. 2+ Ni 2+ With Mn 2+ Cu 2+ The low selectivity of the extraction process results in a separation coefficient β of less than 10 for Co / Ni and Mn / Cu. To achieve the required purity, multiple extraction-back-extraction cycles are required, which not only increases the complexity and operating cost but also reduces the recovery rate of cobalt and nickel. For example, when using P507 extraction to separate Co / Ni and Mn / Cu, the removal rate of Mn and Cu after a single extraction is less than 50%, requiring 3 to 5 multi-stage extractions to reduce the impurity content to the ppm level, with a process cycle of 12 to 24 hours.

[0003] High solvent loss rate: Traditional organic extractants (such as P204 and P507) and diluents (such as kerosene) are prone to emulsification during extraction, making it difficult to completely separate the organic phase from the aqueous phase, resulting in solvent loss. Furthermore, these organic solvents are volatile, and losses occur during stirring and separation operations due to evaporation. According to industrial data, the annual solvent loss rate in traditional extraction processes can reach 5-8%, which not only increases raw material costs but also pollutes the environment due to the toxicity and volatility of organic solvents, contradicting the trend of green chemistry.

[0004] Low process efficiency: Traditional extraction methods often use stirred tank reactors, where mass transfer between the two phases relies on mechanical stirring, resulting in low mass transfer efficiency and long residence times (typically 10-30 minutes). This leads to large equipment footprints and difficulty in improving production efficiency. Furthermore, stirring easily generates a large number of bubbles, further exacerbating emulsification and affecting separation performance.

[0005] To address these issues, researchers have attempted to improve traditional extraction processes. For example, they have used composite extractants (such as a combination of P204 and TBP) to enhance separation selectivity, but the effect is limited, and the separation coefficients of Co / Ni and Mn / Cu remain difficult to exceed 50. Alternatively, they have used novel diluents (such as environmentally friendly vegetable oil-based diluents) to reduce solvent volatility, but the emulsification problem has not been fundamentally solved, and the solvent loss rate remains at 3-4%.

[0006] Ionic liquids, as a novel type of green solvent, possess advantages such as extremely low vapor pressure, good thermal stability, strong solubility, and designable structure, showing broad application prospects in the field of separation and purification. In recent years, research has applied ionic liquids to the extraction and separation of cobalt and nickel; for example, imidazole-based ionic liquids have been used to extract Co. 2+ Ni 2+ However, existing technologies mostly use ionic liquids alone as extraction media without considering their use in conjunction with synergistic extractants, resulting in unsatisfactory selectivity for Mn and Cu impurities. The separation coefficient is usually between 30 and 50, which is difficult to meet the requirements for the preparation of 5N grade high-purity cobalt and nickel. At the same time, existing processes still use traditional stirred tank reactors, which have low contact efficiency between ionic liquids and the aqueous phase, long residence time (>5 min), and are difficult to recover, with recovery rates usually below 95%, which limits their industrial application.

[0007] Therefore, developing a high-purity cobalt-nickel preparation process that can significantly improve the separation selectivity of Co / Ni and Mn / Cu, reduce the loss rate of ionic liquids, and achieve efficient continuous production has become an urgent technical problem to be solved in this field. Summary of the Invention

[0008] The purpose of this invention is to provide a method for ion liquid-enhanced extraction and purification of 5N grade high-purity cobalt and nickel. The method provided by this invention can reduce the loss rate of ion liquid, realize an efficient and continuous production process for high-purity cobalt and nickel, and the obtained cobalt and nickel meet the requirements of 5N grade.

[0009] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for purifying 5N grade high-purity cobalt and nickel using ionic liquid-enhanced extraction, comprising the following steps: (1) After mixing the Co / Ni symbiotic ore and sulfuric acid solution, filter to obtain leachate, and then adjust the pH value of the leachate to 2.0~3.0 to obtain pretreated aqueous raw material; (2) The pretreated aqueous raw material and organic phase obtained in step (1) are mixed in a microchannel reactor and then extracted to obtain a loaded organic phase and raffinate; the organic phase is composed of [BMIM]PF6 ionic liquid and DNNSA; the volume flow ratio of the pretreated aqueous raw material and the organic phase is (1~3):1; (3) The loaded organic phase and the back-extraction agent obtained in step (2) are mixed in a back-extraction microchannel reactor and then back-extracted to obtain back-extraction liquid and regenerated organic phase; (4) The back-extraction solution obtained in step (3) is purified and concentrated by evaporation to obtain a cobalt-nickel electrolyte, which is then electrolytically deposited to obtain a high-purity cobalt-nickel alloy. Alternatively, the back-extraction solution obtained in step (3) can be purified and concentrated by evaporation, and then cobalt and nickel can be separated by ion exchange resin to obtain a cobalt-containing electrolyte and a nickel-containing electrolyte. Finally, the cobalt-containing electrolyte and the nickel-containing electrolyte can be electrolytically deposited to obtain high-purity cobalt and high-purity nickel.

[0010] Preferably, the Co / Ni symbiotic ore in step (1) has a particle size ≤74μm.

[0011] Preferably, the concentration of the sulfuric acid solution in step (1) is 1.5~2.5 mol / L; the ratio of the volume of the sulfuric acid solution to the mass of the Co / Ni symbiotic ore is (3~5) mL:1g.

[0012] Preferably, the Co in the pretreated aqueous raw material in step (1) is... 2+ The concentration is 10~20g / L, Ni 2+ The concentration is 20~30g / L, Mn 2+ The concentration is 1~5 g / L, Cu 2+ The concentration is 0.5~2g / L.

[0013] Preferably, the mass of DNNSA in step (2) is 5-15% of the mass of the [BMIM]PF6 ionic liquid.

[0014] Preferably, the extraction temperature in step (2) is 30~45℃ and the extraction time is 10~30s; the contact mode between the pretreated aqueous raw material and the organic phase in the microchannel reactor is cross-flow contact mode, counter-flow contact mode or co-flow contact mode.

[0015] Preferably, in step (3), the back-extraction agent is hydrochloric acid, and the concentration of hydrochloric acid is 1~2 mol / L; the volume flow ratio of the back-extraction agent to the supported organic phase is (2~4):1.

[0016] Preferably, the temperature of back-extraction in step (3) is 40~55℃ and the time of back-extraction is 15~40s.

[0017] Preferably, in step (3), the regenerated organic phase is subjected to vacuum distillation; the vacuum degree of the vacuum distillation is 0.08~0.1MPa, the temperature of the vacuum distillation is 60~80℃, and the time of the vacuum distillation is 10~20min.

[0018] Preferably, in step (4), the anode for electrolytic deposition is a titanium plate, the cathode for electrolytic deposition is a stainless steel plate, the electrolytic deposition temperature is 50~60℃, and the electrolytic deposition current density is 200~300A / m. 2 The electrolytic deposition time is 8~12h.

[0019] This invention provides a method for purifying 5N grade high-purity cobalt-nickel by ionic liquid enhanced extraction, comprising the following steps: (1) mixing Co / Ni symbiotic ore and sulfuric acid solution and filtering to obtain a leachate, then adjusting the pH of the leachate to 2.0~3.0 to obtain a pretreated aqueous raw material; (2) mixing the pretreated aqueous raw material obtained in step (1) and an organic phase in a microchannel reactor and then extracting to obtain a loaded organic phase and a raffinate; the organic phase is composed of [BMIM]PF6 ionic liquid and DNNSA; the volume flow ratio of the pretreated aqueous raw material to the organic phase is (1~3):1; 3) The loaded organic phase and the back-extractant obtained in step (2) are mixed in a back-extraction microchannel reactor and then back-extracted to obtain back-extraction liquid and regenerated organic phase; (4) The back-extraction liquid obtained in step (3) is purified and concentrated by evaporation to obtain a cobalt-nickel electrolyte, and then electrolytic deposition is performed to obtain a high-purity cobalt-nickel alloy; or, the back-extraction liquid obtained in step (3) is purified and concentrated by evaporation, and then cobalt and nickel are separated by ion exchange resin to obtain a cobalt-containing electrolyte and a nickel-containing electrolyte, and finally electrolytic deposition is performed on the cobalt-containing electrolyte and the nickel-containing electrolyte to obtain high-purity cobalt and high-purity nickel. This invention utilizes a specific ionic liquid as the extraction medium, combined with a synergistic extractant and a microchannel reactor to achieve efficient mass transfer. This significantly improves the separation coefficients of Co / Ni and Mn / Cu, increases the ionic liquid recovery rate, and ultimately yields 5N-grade high-purity cobalt and nickel products. The process is easily scalable for continuous production, overcoming the shortcomings of existing Co / Ni symbiotic ore extraction and purification processes, such as poor selectivity for Mn and Cu impurities, high solvent loss rates, and low process efficiency. Furthermore, this invention significantly improves impurity separation selectivity, reduces solvent consumption, and is highly efficient and environmentally friendly, making it suitable for large-scale industrial production of high-purity cobalt and nickel, providing a crucial raw material guarantee for fields such as new energy and electronic information. The results of the examples show that the cobalt and nickel obtained by the method provided by this invention both meet the 5N grade requirements. Detailed Implementation

[0020] This invention provides a method for purifying 5N grade high-purity cobalt and nickel using ionic liquid-enhanced extraction, comprising the following steps: (1) After mixing the Co / Ni symbiotic ore and sulfuric acid solution, filter to obtain leachate, and then adjust the pH value of the leachate to 2.0~3.0 to obtain pretreated aqueous raw material; (2) The pretreated aqueous raw material and organic phase obtained in step (1) are mixed in a microchannel reactor and then extracted to obtain a loaded organic phase and raffinate; the organic phase is composed of [BMIM]PF6 ionic liquid and DNNSA; the volume flow ratio of the pretreated aqueous raw material and the organic phase is (1~3):1; (3) The loaded organic phase and the back-extraction agent obtained in step (2) are mixed in a back-extraction microchannel reactor and then back-extracted to obtain back-extraction liquid and regenerated organic phase; (4) The back-extraction solution obtained in step (3) is purified and concentrated by evaporation to obtain a cobalt-nickel electrolyte, which is then electrolytically deposited to obtain a high-purity cobalt-nickel alloy. Alternatively, the back-extraction solution obtained in step (3) can be purified and concentrated by evaporation, and then cobalt and nickel can be separated by ion exchange resin to obtain a cobalt-containing electrolyte and a nickel-containing electrolyte. Finally, the cobalt-containing electrolyte and the nickel-containing electrolyte can be electrolytically deposited to obtain high-purity cobalt and high-purity nickel.

[0021] Unless otherwise specified, the raw materials used in this invention are all commercially available products well known to those skilled in the art or products prepared by preparation methods well known to those skilled in the art.

[0022] This invention involves mixing Co / Ni symbiotic ore and sulfuric acid solution, filtering the mixture to obtain a leachate, and then adjusting the pH of the leachate to 2.0-3.0 to obtain a pretreated aqueous raw material.

[0023] In this invention, the particle size of the Co / Ni symbiotic ore is preferably ≤74μm. When the particle size of the Co / Ni symbiotic ore does not meet the above requirement, the Co / Ni symbiotic ore is preferably subjected to crushing, grinding, and sieving sequentially. This invention does not impose special limitations on the specific operations of crushing, grinding, and sieving, as long as the particle size of the Co / Ni symbiotic ore meets the requirements.

[0024] In this invention, the concentration of the sulfuric acid solution is preferably 1.5~2.5 mol / L; the volume ratio of the sulfuric acid solution to the mass of the Co / Ni symbiotic ore is preferably (3~5) mL:1g. As one embodiment of this invention, the concentration of the sulfuric acid solution can be 1.5 mol / L, 1.6 mol / L, 1.8 mol / L, 2 mol / L, 2.2 mol / L, 2.4 mol / L, or 2.5 mol / L; the volume ratio of the sulfuric acid solution to the mass of the Co / Ni symbiotic ore can be 3 mL:1g, 3.2 mL:1g, 3.4 mL:1g, 3.5 mL:1g, 3.6 mL:1g, 3.8 mL:1g, 4 mL:1g, 4.2 mL:1g, 4.4 mL:1g, 4.5 mL:1g, 4.6 mL:1g, 4.8 mL:1g, or 5 mL:1g. This invention removes insoluble impurities such as SiO2 by treating the Co / Ni symbiotic ore with sulfuric acid.

[0025] In this invention, the mixing temperature is preferably 80-95°C; the mixing time is preferably 2-4 hours; the mixing is preferably carried out under stirring conditions; and the stirring rate is preferably 300-500 rpm. As one embodiment of this invention, the mixing temperature can be 80°C, 85°C, 90°C, or 95°C; the mixing time can be 2 hours, 2.5 hours, 3 hours, 3.5 hours, or 4 hours; and the stirring rate can be 300 rpm, 350 rpm, 400 rpm, 450 rpm, or 500 rpm. By controlling the mixing parameters, this invention allows the Co / Ni symbiotic ore and sulfuric acid solution to react fully.

[0026] The present invention does not impose any special limitations on the specific operation of the filtration, as long as it can achieve solid-liquid separation.

[0027] In this invention, the leachate is a Co-containing solution. 2+ Ni 2+ Mn 2+ and Cu 2+ The leachate.

[0028] In this invention, the pH value of the leachate is preferably adjusted by using a sulfuric acid solution or a NaOH solution; the concentration of the sulfuric acid solution or NaOH solution is preferably 0.5~2 mol / L, more preferably 1~1.5 mol / L.

[0029] In this invention, the Co in the pretreated aqueous raw material 2+ The preferred concentration is 10-20 g / L; the Ni content in the pretreated aqueous raw material is... 2+ The preferred concentration of Mn is 20-30 g / L; the Mn content in the pretreated aqueous raw material is... 2+ The preferred concentration is 1~5 g / L; the Cu in the pretreated aqueous raw material 2+ The preferred concentration is 0.5~2 g / L. In one embodiment of the present invention, the Co concentration in the pretreated aqueous raw material is... 2+ The concentration can be 10 g / L, 11 g / L, 12 g / L, 13 g / L, 14 g / L, 15 g / L, 16 g / L, 17 g / L, 18 g / L, 19 g / L, or 20 g / L; the Ni content in the pretreated aqueous raw material... 2+ The concentration can be 20 g / L, 21 g / L, 22 g / L, 23 g / L, 24 g / L, 25 g / L, 26 g / L, 27 g / L, 28 g / L, 29 g / L, or 30 g / L; the Mn content in the pretreated aqueous raw material... 2+ The concentration can be 1 g / L, 2 g / L, 3 g / L, 4 g / L, or 5 g / L; the Cu in the pretreated aqueous raw material 2+The concentration can be 0.5 g / L, 0.8 g / L, 1 g / L, 1.2 g / L, 1.5 g / L, 1.8 g / L or 2 g / L.

[0030] After obtaining the pretreated aqueous raw material, the present invention mixes the pretreated aqueous raw material and the organic phase in a microchannel reactor and then extracts them to obtain the loaded organic phase and the raffinate.

[0031] In this invention, the pretreated aqueous raw material and organic phase are preferably delivered to the feed inlet of the microchannel reactor by metering pumps, and then mixed in the microchannel reactor.

[0032] In this invention, the specific surface area of ​​the microchannel reactor is preferably 5000~8000 m². 2 / m 3 The volume of the microchannel reactor is preferably 10-50 mL. In one embodiment of the invention, the specific surface area of ​​the microchannel reactor can be 5000 m². 2 / m 3 5500m 2 / m 3 6000m 2 / m 3 6500m 2 / m 3 7000m 2 / m 3 7500m 2 / m 3 or 8000m 2 / m 3 The volume of the microchannel reactor is 10 mL, 15 mL, 20 mL, 25 mL, 30 mL, 35 mL, 40 mL, 45 mL or 50 mL.

[0033] In this invention, the organic phase is composed of a mixture of [BMIM]PF6 ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate) and DNNSA (dinonylnaphthalenesulfonic acid); the mass of DNNSA is preferably 5-15% of the mass of [BMIM]PF6 ionic liquid; the preferred method for preparing the organic phase is to add DNNSA to [BMIM]PF6 ionic liquid and stir at a temperature of 40-50°C; the preferred stirring rate is 200-300 rpm; and the preferred stirring time is 30-60 min. In one embodiment of the present invention, the mass of DNNSA can be 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, or 15% of the mass of the [BMIM]PF6 ionic liquid; the stirring rate can be 200 rpm, 210 rpm, 220 rpm, 230 rpm, 240 rpm, 250 rpm, 260 rpm, 270 rpm, 280 rpm, 290 rpm, or 300 rpm; and the stirring time can be 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, or 60 min. The present invention uses [BMIM]PF6 ionic liquid as the extraction medium and adds DNNSA as a synergistic extractant to form an organic phase. By controlling the preparation method, DNNSA can be completely dissolved in the [BMIM]PF6 ionic liquid, resulting in a homogeneous and stable organic phase (extraction system). The reason for choosing [BMIM]PF6 ionic liquid as the extraction medium in this invention is that [BMIM]PF6 ionic liquid has good chemical and thermal stability (decomposition temperature > 300℃) and extremely low vapor pressure (vapor pressure < 10 at 25℃). -6 Pa), which can effectively avoid solvent evaporation loss; at the same time, [BMIM]PF6 ionic liquid has a good effect on Co 2+ and Ni 2+ It has strong dissolving power, and its cation ([BMIM]) + ) can be with Co 2+ and Ni 2+ The formation of a stable coordination structure provides a basis for selective extraction. DNNSA was chosen as the co-extractant because, as an acidic extractant, its sulfonic acid group (-SO3H) can react with [BMIM]. + It forms ion pairs, and the hydrophobic long chains of DNNSA (nonyl, naphthyl) can enhance the hydrophobicity of the organic phase, reducing the miscibility between the organic and aqueous phases; at the same time, DNNSA has a positive effect on Mn 2+ and Cu 2+ The extraction capacity is far lower than that for Co. 2+ and Ni 2+ The extraction capability of [BMIM]PF6 ionic liquid can significantly enhance the extraction efficiency of Co. 2+ Ni2+ With Mn 2+ Cu 2+ Separation selectivity.

[0034] In this invention, the volumetric flow rate ratio (A / O) of the pretreated aqueous feedstock and the synergistic extractant is (1~3):1. As one embodiment of this invention, the volumetric flow rate ratio of the pretreated aqueous feedstock and the synergistic extractant is 1:1, 1.2:1, 1.5:1, 1.8:1, 2:1, 2.2:1, 2.5:1, 2.8:1, or 3:1.

[0035] In this invention, the extraction temperature is preferably 30-45℃; the extraction time is preferably 10-30s; the contact mode between the pretreated aqueous raw material and the organic phase in the microchannel reactor is preferably cross-flow contact, counter-flow contact, or co-flow contact, more preferably cross-flow contact; the extraction time is calculated from the total flow rate of the pretreated aqueous raw material and the organic phase and the microchannel volume of the microchannel reactor; the total flow rate of the pretreated aqueous raw material and the organic phase is preferably 20-300mL / min; the microchannel volume of the microchannel reactor is preferably 10-50mL. In one embodiment of the present invention, the extraction temperature can be 30℃, 35℃, 40℃, or 45℃; the extraction time can be 10s, 15s, 20s, 25s, or 30s; the total flow rate of the pretreated aqueous raw material and organic phase can be 20mL / min, 30mL / min, 40mL / min, 50mL / min, 60mL / min, 70mL / min, 80mL / min, 90mL / min, 100mL / min, 120mL / min, 140mL / min, 150mL / min, 160mL / min, 180mL / min, 200mL / min, 220mL / min, 240mL / min, 250mL / min, 260mL / min, 280mL / min, or 300mL / min; and the microchannel volume of the microchannel reactor can be 10mL, 15mL, 20mL, 25mL, 30mL, 35mL, 40mL, 45mL, or 50mL. This invention achieves efficient mass transfer by controlling the contact mode between the pretreated aqueous raw material and the organic phase, thus enabling Co... 2+ Ni 2+ Mn is preferentially extracted by the organic phase. 2+ and Cu 2+ It mainly remains in the aqueous phase, yielding a product containing Co. 2+ Ni 2+ Supported organic phase and Mn-containing 2+ Cu 2+ The residual extract.

[0036] The advantages of using a microchannel reactor in this invention are: the microchannels have a large specific surface area, which can significantly increase the contact area between the aqueous and organic phases; at the same time, the flow within the microchannels is laminar or enhanced turbulent, with a high mass transfer coefficient (up to 5-10 times that of traditional stirred tanks), enabling the rapid deposition of Co in a short time (<30s). 2+ Ni 2+ It achieves efficient extraction and avoids emulsification caused by stirring in traditional stirred tanks, thus reducing the loss of organic phase.

[0037] After obtaining the supported organic phase, the present invention mixes the supported organic phase and the back-extraction agent in a microchannel reactor and then performs back-extraction to obtain the back-extraction solution and the regenerated organic phase.

[0038] In this invention, the supported organic phase and the back-extractant are preferably delivered to the feed inlet of the microchannel reactor via metering pumps, and then mixed in the microchannel reactor.

[0039] In this invention, the back-extraction agent is preferably hydrochloric acid; the concentration of the hydrochloric acid is preferably 1-2 mol / L; and the volumetric flow rate ratio (A / O) of the back-extraction agent to the supported organic phase is preferably (2-4):1. As one embodiment of this invention, the concentration of the hydrochloric acid can be 1 mol / L, 1.2 mol / L, 1.4 mol / L, 1.5 mol / L, 1.6 mol / L, 1.8 mol / L, or 2 mol / L; and the volumetric flow rate ratio of the back-extraction agent to the supported organic phase can be 2:1, 2.2:1, 2.5:1, 2.8:1, 3:1, 3.2:1, 3.5:1, 3.8:1, or 4:1. The reason for controlling the hydrochloric acid concentration in this invention is that too low a concentration will lead to insufficient back-extraction efficiency (Co). 2+ Ni 2+ If the resolution is less than 90%, and the concentration is too high, the protonation degree of DNNSA will be too high, which will affect the recycling performance of the regenerated organic phase.

[0040] In this invention, the back-extraction temperature is preferably 40-55°C; the back-extraction time is preferably 15-40 seconds. As one embodiment of this invention, the back-extraction temperature can be 40°C, 45°C, 50°C, or 55°C; the back-extraction time can be 15 seconds, 20 seconds, 25 seconds, 30 seconds, 35 seconds, or 40 seconds. During the back-extraction process, Co in the supported organic phase... 2+ Ni 2+ It was desorbed by hydrochloric acid solution and entered the aqueous phase, yielding a product containing Co. 2+ Ni 2+ The back-extraction solution and the regenerated organic phase (mainly composed of [BMIM]PF6 ionic liquid and DNNSA).

[0041] After obtaining the back-extraction solution and the regenerated organic phase, the present invention purifies and removes impurities from the back-extraction solution and evaporates and concentrates it to obtain a cobalt-nickel electrolyte, and then performs electrolytic deposition to obtain a high-purity cobalt-nickel alloy.

[0042] In this invention, the preferred method for purification and impurity removal is to mix the back-extraction solution and sodium sulfide solution, precipitate the mixture, and then filter it. In this invention, the concentration of the sodium sulfide solution is preferably 0.5~1 mol / L; the pH value of the mixture of the back-extraction solution and sodium sulfide solution is preferably 4.0~5.0; the precipitation temperature is preferably 50~60℃; the precipitation time is preferably 30~60 min; and the precipitation is preferably carried out under stirring conditions. In one embodiment of the present invention, the concentration of the sodium sulfide solution can be 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, or 1 mol / L; the pH value of the mixture of the back-extraction solution and the sodium sulfide solution can be 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, or 5.0; the precipitation temperature can be 50℃, 52℃, 54℃, 55℃, 56℃, 58℃, or 60℃; and the precipitation time can be 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, or 60 min. The present invention does not impose any special limitations on the stirring rate and filtration operation; based on the technical knowledge of those skilled in the art, it is sufficient to achieve uniform stirring and solid-liquid separation. The present invention, through purification and impurity removal, can remove trace amounts of Mn remaining in the back-extraction solution. 2+ Cu 2+ Sulfide precipitates (MnS, CuS) are formed, and then the precipitates are removed by filtration.

[0043] In this invention, the preferred temperature for evaporation and concentration is 80-95°C; the preferred vacuum degree for evaporation and concentration is 0.06-0.08 MPa; and the product of evaporation and concentration contains Co. 2+ and Ni 2+ The total concentration is preferably 80-100 g / L. In one embodiment of the invention, the evaporation and concentration temperature can be 80°C, 85°C, 90°C, or 95°C; the vacuum degree of the evaporation and concentration can be 0.06 MPa, 0.07 MPa, or 0.08 MPa; the Co content in the evaporation and concentration product is... 2+ and Ni 2+ The total concentration can be 80 g / L, 85 g / L, 90 g / L, 95 g / L, or 100 g / L. This invention removes excess solvent through evaporation and concentration, facilitating subsequent electrolytic deposition.

[0044] In this invention, the anode for electrolytic deposition is preferably a titanium plate; the cathode for electrolytic deposition is preferably a stainless steel plate; the electrolyte for electrolytic deposition is preferably a cobalt-nickel-containing electrolyte; the temperature for electrolytic deposition is preferably 50-60°C; and the current density for electrolytic deposition is preferably 200-300 A / m. 2 The preferred electrolytic deposition time is 8-12 hours. In one embodiment of the invention, the electrolytic deposition temperature can be 50°C, 52°C, 54°C, 55°C, 56°C, 58°C, or 60°C; the electrolytic deposition current density can be 200 A / m. 2 210A / m 2 220A / m 2 230A / m 2 240A / m 2 250A / m 2 260A / m 2 270A / m 2 280A / m 2 290A / m 2 Or 300A / m 2 The electrolytic deposition time can be 8h, 9h, 10h, 11h or 12h.

[0045] After obtaining the back-extraction solution and the regenerated organic phase, the back-extraction solution is purified and concentrated by evaporation in sequence. Then, cobalt and nickel are separated by ion exchange resin to obtain a cobalt-containing electrolyte and a nickel-containing electrolyte. Finally, the cobalt-containing electrolyte and the nickel-containing electrolyte are electrolytically deposited to obtain high-purity cobalt and high-purity nickel.

[0046] In this invention, the specific parameters for purification, impurity removal, and evaporation concentration are preferably the same as those described above, and will not be repeated here.

[0047] In this invention, the ion exchange resin is preferably D851 chelating resin. This invention does not impose any specific limitation on the amount of ion exchange resin used; based on the technical knowledge of those skilled in the art, it is sufficient to achieve cobalt-nickel separation.

[0048] In this invention, the specific operation of the electrolytic deposition is preferably the same as described above, and will not be repeated here.

[0049] In this invention, the regenerated organic phase is preferably subjected to vacuum distillation to obtain a purified organic phase; the purified organic phase is preferably used for extraction of pretreated aqueous raw materials. In this invention, the vacuum degree of the vacuum distillation is preferably 0.08~0.1 MPa; the temperature of the vacuum distillation is preferably 60~80℃; and the time of the vacuum distillation is preferably 10~20 min. As one embodiment of this invention, the vacuum degree of the vacuum distillation can be 0.08 MPa, 0.09 MPa, or 0.1 MPa; the temperature of the vacuum distillation can be 60℃, 65℃, 70℃, 75℃, or 80℃; and the time of the vacuum distillation can be 10 min, 12 min, 14 min, 15 min, 16 min, 18 min, or 20 min. This invention removes trace amounts of water and hydrochloric acid (water content reduced to <0.1%) that may remain in the regenerated organic phase through vacuum distillation, yielding a purified organic phase that is an ionic liquid extraction system ([BMIM]PF6 ionic liquid + DNNSA). This purified organic phase can be used for the extraction of pretreated aqueous raw materials, enabling the recycling of the organic phase and the recovery of the ionic liquid. Testing showed that the organic phase recovery rate was ≥99%, and after 50 cycles, the performance of the organic phase (such as separation coefficient and extraction capacity) did not significantly decrease (the separation coefficient remained >180).

[0050] This invention utilizes a specific ionic liquid as the extraction medium, combined with a synergistic extractant and a microchannel reactor to achieve efficient mass transfer. This significantly improves the separation coefficients of Co / Ni and Mn / Cu, increases the ionic liquid recovery rate, and ultimately yields 5N-grade high-purity cobalt-nickel products. Furthermore, the process is easily scalable for continuous production, overcoming the shortcomings of existing Co / Ni symbiotic ore extraction and purification processes, such as poor selectivity for Mn and Cu impurities, high solvent loss rates, and low process efficiency. Simultaneously, this invention significantly improves impurity separation selectivity, reduces solvent consumption, and is highly efficient and environmentally friendly, making it suitable for large-scale industrial production of high-purity cobalt-nickel, providing a crucial raw material guarantee for new energy and electronic information fields.

[0051] The present invention has the following significant technical effects: Significantly improved separation selectivity: Through the combined use of [BMIM]PF6 ionic liquid and DNNSA synergistic extractant, as well as the efficient mass transfer effect of the microchannel reactor, the separation coefficient β of Co / Ni and Mn / Cu is increased from <10 in the traditional process to >200. A single extraction can improve the removal rate of Mn and Cu impurities to over 99%, eliminating the need for multiple extraction-back-extraction cycles, greatly simplifying the process and reducing operating costs.

[0052] Low ionic liquid loss rate: [BMIM]PF6 ionic liquid has an extremely low vapor pressure, and the microchannel reactor avoids the emulsification problem of traditional stirred tank reactors, reducing the dispersion loss of organic phase; at the same time, the organic phase is recovered and regenerated by vacuum distillation, and the ionic liquid recovery rate is ≥99%, which is much higher than <95% of the existing ionic liquid extraction process, significantly reducing solvent costs and reducing environmental pollution.

[0053] High process efficiency: The microchannel reactor has high mass transfer efficiency, with a two-phase residence time of <30s, which is much lower than the 10~30min of the traditional stirred tank. The process cycle is shortened to 1 / 20~1 / 50 of the traditional process. At the same time, the microchannel reactor has a small volume (single reactor volume <100mL), and the equipment occupies only 1 / 100 of the area of ​​the traditional stirred tank, making it easy to achieve large-scale continuous production.

[0054] High product purity: The cobalt-nickel alloy, cobalt products and nickel products obtained by this invention have a purity of 5N grade (99.999%), in which the content of Mn and Cu impurities is <0.5ppm, which meets the stringent requirements for high-purity cobalt and nickel in the fields of new energy power batteries, high-temperature alloys and electronic information.

[0055] The process is green and environmentally friendly: [BMIM]PF6 ionic liquid is non-volatile, DNNSA has low toxicity, and the entire process has no harmful gas emissions. The organic phase can be recycled, which meets the requirements of green chemical industry and sustainable development.

[0056] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0057] Example 1 A method for purifying 5N grade high-purity cobalt and nickel using ionic liquid-enhanced extraction comprises the following steps: (1) The Co / Ni symbiotic ore (composed of: Co 3.2%, Ni 6.5%, Mn 1.1%, Cu 0.3%, SiO2 45.2%, particle size ≤74μm by mass percentage) and sulfuric acid solution were mixed under stirring and then filtered to obtain a Co-containing ore. 2+ Ni 2+ Mn 2+ and Cu 2+ The leachate was then subjected to a 1 mol / L NaOH solution to adjust the pH of the leachate to 2.5, resulting in a pretreated aqueous raw material. Analysis revealed that the composition of the pretreated aqueous raw material was: Co... 2+ 15.2g / L, Ni 2+25.6 g / L, Mn 2+ 3.2 g / L and Cu 2+ 0.8 g / L; the concentration of the sulfuric acid solution is 2 mol / L; the volume ratio of the sulfuric acid solution to the mass of the Co / Ni symbiotic ore is 5 mL: 1 g; the mixing temperature is 90 °C, the time is 3 h, and the stirring speed is 400 rpm; (2) The pretreated aqueous phase and organic phase obtained in step (1) are respectively pumped to the feed inlet of the microchannel reactor through metering pumps, and then mixed and extracted in the microchannel reactor to obtain the loaded organic phase and raffinate. After detection, the composition of the raffinate is: Co 2+ 0.07g / L, Ni 2+ 0.12g / L, Mn 2+ 3.18 g / L and Cu 2+ 0.79 g / L, the separation coefficient β between Co / Ni and Mn / Cu was calculated to be 225; the specific surface area of ​​the microchannel reactor is 7500 m². 2 / m 3 The volume of the organic phase is 30 mL. The organic phase is prepared by adding DNNSA to [BMIM]PF6 ionic liquid at 45℃ and 250 rpm for 45 min, with the mass of DNNSA being 10% of the mass of [BMIM]PF6 ionic liquid. The volume ratio of the pretreated aqueous phase to the organic phase is 2:1. The extraction temperature is 40℃ and the extraction time is 15 s. The contact mode between the pretreated aqueous phase and the organic phase in the microchannel reactor is cross-flow contact. The extraction time is calculated from the total flow rate of the pretreated aqueous phase and the organic phase and the microchannel volume of the microchannel reactor. The total flow rate of the pretreated aqueous phase and the organic phase is 120 mL / min, the microchannel volume is 30 mL, and 30 mL / 120 mL / min = 15 s. (3) The loaded organic phase and back-extraction agent obtained in step (2) are respectively pumped to the inlet of the microchannel reactor (the same model as the microchannel reactor in step (2)) by metering pumps, and then mixed in the microchannel reactor for back-extraction to obtain back-extraction liquid and regenerated organic phase. After detection, the composition of the back-extraction liquid is: Co 2+ 59.8g / L, Ni 2+ 101.5g / L, Mn 2+ 0.02 g / L and Cu 2+ 0.01g / L, Co 2+ Ni 2+The resolution was >99.5%; the back-extraction agent was 1.5 mol / L hydrochloric acid, and the volumetric flow rate ratio (A / O) of the back-extraction agent to the supported organic phase was 3:1; the back-extraction temperature was 50℃, the time was 15s, the total flow rate was 150mL / min, the microchannel volume was 30mL, and 30mL / 150mL / min = 12s. In actual operation, there were slight fluctuations, so the time was set to 15s. (4) The back-extraction solution obtained in step (3) is mixed with a sodium sulfide solution with a concentration of 0.8 mol / L (the pH value of the mixture is 4.5), and then precipitated under stirring. After filtration, the solution is evaporated and concentrated to Co at 90°C and a vacuum of 0.07 MPa. 2+ and Ni 2+ The total concentration was 90 g / L. Cobalt and nickel were then separated using D851 chelating resin to obtain cobalt-containing and nickel-containing electrolytes. Finally, the cobalt-containing and nickel-containing electrolytes were electrolytically deposited to obtain high-purity cobalt and high-purity nickel, respectively. The anode for the electrolytic deposition was a titanium plate, the cathode was a stainless steel plate, and the electrolytes were the cobalt-containing and nickel-containing electrolytes, respectively. The electrolytic deposition temperature was 55℃, and the current density was 250 A / m. 2 The time was 10 hours; the regenerated organic phase was subjected to vacuum distillation to obtain a purified organic phase (recovery rate of 99.3%). The vacuum distillation process was carried out at a vacuum degree of 0.09 MPa, a temperature of 70°C, and a time of 15 minutes.

[0058] The purity of the high-purity cobalt and high-purity nickel obtained in Example 1 was analyzed by GD-MS (glow discharge mass spectrometry). The purity of the high-purity cobalt was 99.9992% (Mn 0.3ppm, Cu 0.2ppm), and the purity of the high-purity nickel was 99.9991% (Mn 0.4ppm, Cu 0.3ppm), both meeting the requirements of 5N grade.

[0059] Example 2 A method for purifying 5N grade high-purity cobalt and nickel using ionic liquid-enhanced extraction comprises the following steps: (1) The Co / Ni symbiotic ore (composed of: Co 2.8%, Ni 5.9%, Mn 0.8%, Cu 0.2%, SiO2 48.5%, particle size ≤74μm by mass percentage) and sulfuric acid solution were mixed under stirring and then filtered to obtain a Co-containing ore. 2+ Ni 2+ Mn 2+ and Cu 2+ The leachate was then treated with 1 mol / L sulfuric acid solution to adjust the pH to 2.2, yielding a pretreated aqueous raw material. Analysis revealed the following composition of the pretreated aqueous raw material: Co 2+ 12.1 g / L, Ni2+ 23.5g / L, Mn 2+ 2.1 g / L and Cu 2+ 0.5 g / L; the concentration of the sulfuric acid solution is 1.8 mol / L; the volume ratio of the sulfuric acid solution to the mass ratio of the Co / Ni symbiotic ore is 3 mL: 1 g; the mixing temperature is 85 °C, the time is 2.5 h, and the stirring speed is 350 rpm; (2) The pretreated aqueous phase and organic phase obtained in step (1) are respectively pumped to the feed inlet of the microchannel reactor through metering pumps, and then mixed and extracted in the microchannel reactor to obtain the loaded organic phase and raffinate. After detection, the composition of the raffinate is: Co 2+ 0.05g / L, Ni 2+ 0.09 g / L, Mn 2+ 2.08 g / L and Cu 2+ 0.49 g / L, the separation coefficient β between Co / Ni and Mn / Cu was calculated to be 208; the specific surface area of ​​the microchannel reactor is 6000 m². 2 / m 3 The volume of the organic phase is 20 mL. The organic phase is prepared as follows: DNNSA is added to [BMIM]PF6 ionic liquid at 40℃ and a stirring rate of 200 rpm for 30 min, with the mass of DNNSA being 5% of the mass of [BMIM]PF6 ionic liquid. The volumetric flow ratio of the pretreated aqueous phase to the organic phase is 1:1. The extraction temperature is 35℃, and the extraction time is 25 s. The contact mode between the pretreated aqueous phase and the organic phase in the microchannel reactor is a cross-flow contact mode. The extraction time is calculated from the total flow rate of the pretreated aqueous phase and the organic phase and the microchannel volume of the microchannel reactor. The total flow rate of the pretreated aqueous phase and the organic phase is 80 mL / min, the microchannel volume is 20 mL, and 20 mL / 80 mL / min = 15 s. (3) The loaded organic phase and back-extraction agent obtained in step (2) are respectively pumped to the inlet of a microchannel reactor (the same model as the microchannel reactor in step (2)) by metering pumps, and then mixed in the microchannel reactor for back-extraction to obtain back-extraction solution and regenerated organic phase. After detection, the Co in the back-extraction solution is... 2+ Ni 2+ The resolution was >99.2%; the back-extraction agent was hydrochloric acid with a concentration of 1.2 mol / L, and the volumetric flow rate ratio (A / O) of the back-extraction agent to the supported organic phase was 2:1; the back-extraction temperature was 45℃, the back-extraction time was 12s, the total flow rate was 80mL / min, the microchannel volume was 20mL, and 20mL / 80mL / min=12s; (4) The back-extraction solution obtained in step (3) is mixed with a sodium sulfide solution with a concentration of 0.8 mol / L (the pH value of the mixture is 4.5), and then precipitated under stirring. After filtration, the solution is evaporated and concentrated to Co at 90°C and a vacuum of 0.07 MPa. 2+ and Ni 2+ The total concentration was 90 g / L. Cobalt and nickel were then separated using D851 chelating resin to obtain cobalt-containing and nickel-containing electrolytes. Finally, the cobalt-containing and nickel-containing electrolytes were electrolytically deposited to obtain high-purity cobalt and high-purity nickel, respectively. The anode for the electrolytic deposition was a titanium plate, the cathode was a stainless steel plate, and the electrolytes were the cobalt-containing and nickel-containing electrolytes, respectively. The electrolytic deposition temperature was 55℃, and the current density was 250 A / m. 2 The time was 10 hours; the regenerated organic phase was subjected to vacuum distillation to obtain a purified organic phase (recovery rate of 99.1%). The vacuum distillation process was carried out at a vacuum degree of 0.08 MPa, a temperature of 65°C, and a time of 12 minutes.

[0060] The purity of the high-purity cobalt and high-purity nickel obtained in Example 2 was analyzed by GD-MS (glow discharge mass spectrometry). The purity of the high-purity cobalt was 99.9990% (Mn 0.4ppm, Cu 0.3ppm), and the purity of the high-purity nickel was 99.9989% (Mn 0.5ppm, Cu 0.4ppm), both meeting the requirements of 5N grade.

[0061] Example 3 A method for purifying 5N grade high-purity cobalt and nickel using ionic liquid-enhanced extraction comprises the following steps: (1) The Co / Ni symbiotic ore (composed of: Co 3.5%, Ni 7.2%, Mn 1.5%, Cu 0.4%, SiO2 42.8%, particle size ≤74μm by mass percentage) and sulfuric acid solution were mixed under stirring and then filtered to obtain a Co-containing ore. 2+ Ni 2+ Mn 2+ and Cu 2+ The leachate was then subjected to a 1 mol / L NaOH solution to adjust the pH of the leachate to 2.8, resulting in a pretreated aqueous raw material. Analysis revealed that the composition of the pretreated aqueous raw material was: Co... 2+ 18.3g / L, Ni 2+ 28.7g / L, Mn 2+ 4.8 g / L and Cu 2+ 1.2 g / L; the concentration of the sulfuric acid solution is 2.2 mol / L; the volume ratio of the sulfuric acid solution to the mass ratio of the Co / Ni symbiotic ore is 4 mL: 1 g; the mixing temperature is 95 °C, the time is 4 h, and the stirring speed is 500 rpm; (2) The pretreated aqueous phase and organic phase obtained in step (1) are respectively pumped to the feed inlet of the microchannel reactor through metering pumps, and then mixed and extracted in the microchannel reactor to obtain the loaded organic phase and raffinate. After detection, the composition of the raffinate is: Co 2+ 0.08g / L, Ni 2+ 0.15g / L, Mn 2+ 4.78 g / L and Cu 2+ 1.19 g / L, the separation coefficient β of Co / Ni and Mn / Cu was calculated to be 232; the specific surface area of ​​the microchannel reactor is 8000 m². 2 / m 3 The volume of the organic phase is 50 mL. The organic phase is prepared by adding DNNSA to [BMIM]PF6 ionic liquid at 50℃ and 300 rpm for 60 min, with the mass of DNNSA being 15% of the mass of [BMIM]PF6 ionic liquid. The volume flow ratio of the pretreated aqueous phase to the organic phase is 3:1. The extraction temperature is 45℃ and the extraction time is 10 s. The contact mode between the pretreated aqueous phase and the organic phase in the microchannel reactor is cross-flow contact. The extraction time is calculated from the total flow rate of the pretreated aqueous phase and the organic phase and the microchannel volume of the microchannel reactor. The total flow rate of the pretreated aqueous phase and the organic phase is 300 mL / min, the microchannel volume is 50 mL, and 50 mL / 300 mL / min = 10 s. (3) The loaded organic phase and back-extraction agent obtained in step (2) are respectively pumped to the inlet of a microchannel reactor (the same model as the microchannel reactor in step (2)) by metering pumps, and then mixed in the microchannel reactor for back-extraction to obtain back-extraction liquid and regenerated organic phase. After detection, the Co content in the back-extraction liquid is found to be... 2+ Ni 2+ The resolution was >99.6%; the back-extraction agent was hydrochloric acid with a concentration of 1.8 mol / L, and the volumetric flow rate ratio (A / O) of the back-extraction agent to the supported organic phase was 4:1; the back-extraction temperature was 55℃, the time was 12s, the total flow rate was 250mL / min, the microchannel volume was 50mL, and 50mL / 250mL / min=12s; (4) The back-extraction solution obtained in step (3) is mixed with a sodium sulfide solution with a concentration of 0.8 mol / L (the pH value of the mixture is 4.5), and then precipitated under stirring. After filtration, the solution is evaporated and concentrated to Co at 90°C and a vacuum of 0.07 MPa. 2+ and Ni 2+The total concentration was 90 g / L. Cobalt and nickel were then separated using D851 chelating resin to obtain cobalt-containing and nickel-containing electrolytes. Finally, the cobalt-containing and nickel-containing electrolytes were electrolytically deposited to obtain high-purity cobalt and high-purity nickel, respectively. The anode for the electrolytic deposition was a titanium plate, the cathode was a stainless steel plate, and the electrolytes were the cobalt-containing and nickel-containing electrolytes, respectively. The electrolytic deposition temperature was 55℃, and the current density was 250 A / m. 2 The time was 10 hours; the regenerated organic phase was subjected to vacuum distillation to obtain a purified organic phase (recovery rate of 99.3%). The vacuum distillation process was carried out at a vacuum degree of 0.1 MPa, a temperature of 80°C, and a time of 20 minutes.

[0062] The purity of the high-purity cobalt and high-purity nickel obtained in Example 3 was analyzed by GD-MS (glow discharge mass spectrometry). The purity of the high-purity cobalt was 99.9993% (Mn 0.2ppm, Cu 0.1ppm), and the purity of the high-purity nickel was 99.9992% (Mn 0.3ppm, Cu 0.2ppm), both meeting the requirements of 5N grade.

[0063] Comparative Example 1 A method for purifying cobalt and nickel comprises the following steps: (1) The Co / Ni symbiotic ore (composed of: Co 3.2%, Ni 6.5%, Mn 1.1%, Cu 0.3%, SiO2 45.2%, particle size ≤74μm by mass percentage) and sulfuric acid solution were mixed under stirring and then filtered to obtain a Co-containing ore. 2+ Ni 2+ Mn 2+ and Cu 2+ The leachate was then subjected to a 1 mol / L NaOH solution to adjust the pH of the leachate to 2.5, resulting in a pretreated aqueous raw material. Analysis revealed that the composition of the pretreated aqueous raw material was: Co... 2+ 15.2g / L, Ni 2+ 25.6 g / L, Mn 2+ 3.2 g / L and Cu 2+ 0.8 g / L; the concentration of the sulfuric acid solution is 2 mol / L; the volume ratio of the sulfuric acid solution to the mass of the Co / Ni symbiotic ore is 5 mL: 1 g; the mixing temperature is 90 °C, the time is 3 h, and the stirring speed is 400 rpm; (2) The pretreated aqueous raw material and organic phase obtained in step (1) are mixed in a stirred tank and then extracted to obtain a loaded organic phase and raffinate. After testing, the composition of the raffinate is: Co 2+ 1.5g / L, Ni 2+ 2.6g / L, Mn 2+ 2.8 g / L and Cu2+ 0.7 g / L, the separation coefficient β of Co / Ni and Mn / Cu was calculated to be 8.5; the preparation method of the organic phase is as follows: P507 and sulfonated kerosene are mixed and stirred for 30 min, and the mass percentage of P507 in the organic phase is 15%; the volume flow ratio of the pretreated aqueous raw material to the organic phase is 2:1; the stirring speed during mixing is 300 rpm, the extraction temperature is 40℃, and the extraction time is 20 min; (3) The loaded organic phase and the back-extraction agent obtained in step (2) are mixed in a stirred tank for back-extraction to obtain a back-extraction solution and a regenerated organic phase. After testing, the Co content in the back-extraction solution is found to be... 2+ Ni 2+ The resolution was >92.3%; the back-extraction agent was hydrochloric acid with a concentration of 1.5 mol / L, and the volumetric flow rate ratio (A / O) of the back-extraction agent to the supported organic phase was 3:1; the mixing speed was 200 rpm, the back-extraction temperature was 50℃, and the time was 15 min; (4) The back-extraction solution obtained in step (3) is mixed with a sodium sulfide solution with a concentration of 0.8 mol / L (the pH value of the mixture is 4.5), and then precipitated under stirring. After filtration, the solution is evaporated and concentrated to Co at 90°C and a vacuum of 0.07 MPa. 2+ and Ni 2+ The total concentration was 90 g / L. Cobalt and nickel were then separated using D851 chelating resin to obtain cobalt-containing and nickel-containing electrolytes. Finally, the cobalt-containing and nickel-containing electrolytes were electrolytically deposited to obtain high-purity cobalt and high-purity nickel, respectively. The anode for the electrolytic deposition was a titanium plate, the cathode was a stainless steel plate, and the electrolytes were the cobalt-containing and nickel-containing electrolytes, respectively. The electrolytic deposition temperature was 55℃, and the current density was 250 A / m. 2 The time is 10 hours; the regenerated organic phase is allowed to stand to remove the aqueous phase, and the purified organic phase is obtained (the recovery rate is 92.5%, and some organic phase is lost due to emulsification).

[0064] The purity of the high-purity cobalt and high-purity nickel obtained from Comparative Example 1 was analyzed by GD-MS (glow discharge mass spectrometry). The purity of high-purity cobalt was 99.99% (Mn 5.2ppm, Cu 4.8ppm), and the purity of high-purity nickel was 99.99% (Mn 6.1ppm, Cu 5.3ppm), neither of which met the requirements of 5N grade.

[0065] Comparative Example 2 A method for purifying 5N grade high-purity cobalt and nickel using ionic liquid-enhanced extraction comprises the following steps: (1) The Co / Ni symbiotic ore (composed of: Co 3.2%, Ni 6.5%, Mn 1.1%, Cu 0.3%, SiO2 45.2%, particle size ≤74μm by mass percentage) and sulfuric acid solution were mixed under stirring and then filtered to obtain a Co-containing ore. 2+ Ni 2+ Mn 2+ and Cu 2+ The leachate was then subjected to a 1 mol / L NaOH solution to adjust the pH of the leachate to 2.5, resulting in a pretreated aqueous raw material. Analysis revealed that the composition of the pretreated aqueous raw material was: Co... 2+ 15.2g / L, Ni 2+ 25.6 g / L, Mn 2+ 3.2 g / L and Cu 2+ 0.8 g / L; the concentration of the sulfuric acid solution is 2 mol / L; the volume ratio of the sulfuric acid solution to the mass of the Co / Ni symbiotic ore is 5 mL: 1 g; the mixing temperature is 90 °C, the time is 3 h, and the stirring speed is 400 rpm; (2) The pretreated aqueous phase and organic phase obtained in step (1) are respectively pumped to the feed inlet of the microchannel reactor through metering pumps, and then mixed and extracted in the microchannel reactor to obtain the loaded organic phase and raffinate. After detection, the composition of the raffinate is: Co 2+ 0.5g / L, Ni 2+ 0.8g / L, Mn 2+ 2.9 g / L and Cu 2+ 0.6 g / L, the separation coefficient β between Co / Ni and Mn / Cu was calculated to be 45; the specific surface area of ​​the microchannel reactor is 7500 m². 2 / m 3 The volume is 30 mL; the organic phase is [BMIM]PF6 ionic liquid; the volume flow ratio of the pretreated aqueous phase to the organic phase is 2:1; the extraction temperature is 40℃, and the extraction time is 15 s; the contact mode of the pretreated aqueous phase and the organic phase in the microchannel reactor is cross-flow contact; the extraction time is calculated from the total flow rate of the pretreated aqueous phase and the organic phase and the microchannel volume of the microchannel reactor; the total flow rate of the pretreated aqueous phase and the organic phase is 120 mL / min, the microchannel volume is 30 mL, and 30 mL / 120 mL / min = 15 s; (3) The loaded organic phase and the back-extractant obtained in step (2) are respectively delivered to the inlet of the microchannel reactor (the same model as the microchannel reactor in step (2)) by metering pumps, and then mixed in the microchannel reactor for back-extraction to obtain back-extraction liquid and regenerated organic phase; the back-extractant is hydrochloric acid with a concentration of 1.5 mol / L, and the volume flow ratio (A / O) of the back-extractant to the loaded organic phase is 3:1; the back-extraction temperature is 50℃ and the time is 15s; (4) The back-extraction solution obtained in step (3) is mixed with a sodium sulfide solution with a concentration of 0.8 mol / L (the pH value of the mixture is 4.5), and then precipitated under stirring. After filtration, the solution is evaporated and concentrated to Co at 90°C and a vacuum of 0.07 MPa. 2+ and Ni 2+ The total concentration was 90 g / L. Cobalt and nickel were then separated using D851 chelating resin to obtain cobalt-containing and nickel-containing electrolytes. Finally, the cobalt-containing and nickel-containing electrolytes were electrolytically deposited to obtain high-purity cobalt and high-purity nickel, respectively. The anode for the electrolytic deposition was a titanium plate, the cathode was a stainless steel plate, and the electrolytes were the cobalt-containing and nickel-containing electrolytes, respectively. The electrolytic deposition temperature was 55℃, and the current density was 250 A / m. 2 The time is 10 hours; the regenerated organic phase is subjected to vacuum distillation to obtain a purified organic phase. The vacuum distillation process is carried out at a vacuum degree of 0.09 MPa, a temperature of 70°C, and a time of 15 minutes.

[0066] The purity of the high-purity cobalt and high-purity nickel obtained in Comparative Example 2 was analyzed by GD-MS (glow discharge mass spectrometry). The purity of high-purity cobalt was 99.995% (Mn 2.1ppm, Cu 1.8ppm), and the purity of high-purity nickel was 99.995% (Mn 2.5ppm, Cu 2.2ppm), neither of which met the requirements of 5N grade.

[0067] Comparative Example 3 A method for purifying 5N grade high-purity cobalt and nickel using ionic liquid-enhanced extraction comprises the following steps: (1) The Co / Ni symbiotic ore (composed of: Co 3.2%, Ni 6.5%, Mn 1.1%, Cu 0.3%, SiO2 45.2%, particle size ≤74μm by mass percentage) and sulfuric acid solution were mixed under stirring and then filtered to obtain a Co-containing ore. 2+ Ni 2+ Mn 2+ and Cu 2+ The leachate was then subjected to a 1 mol / L NaOH solution to adjust the pH of the leachate to 2.5, resulting in a pretreated aqueous raw material. Analysis revealed that the composition of the pretreated aqueous raw material was: Co... 2+15.2g / L, Ni 2+ 25.6 g / L, Mn 2+ 3.2 g / L and Cu 2+ 0.8 g / L; the concentration of the sulfuric acid solution is 2 mol / L; the volume ratio of the sulfuric acid solution to the mass of the Co / Ni symbiotic ore is 5 mL: 1 g; the mixing temperature is 90 °C, the time is 3 h, and the stirring speed is 400 rpm; (2) The pretreated aqueous raw material and organic phase obtained in step (1) are mixed in a stirred tank and then extracted to obtain a loaded organic phase and raffinate. After testing, the composition of the raffinate is: Co 2+ 0.2g / L, Ni 2+ 0.3g / L, Mn 2+ 3.1 g / L and Cu 2+ 0.75 g / L, the separation coefficient β of Co / Ni and Mn / Cu was calculated to be 85; the organic phase was prepared by adding DNNSA to [BMIM]PF6 ionic liquid at 45℃ and 250 rpm for 45 min, the mass of DNNSA being 10% of the mass of [BMIM]PF6 ionic liquid; the volumetric flow ratio of the pretreated aqueous phase to the organic phase was 2:1; the stirring rate was 300 rpm, the extraction temperature was 40℃, and the extraction time was 20 min; (3) The loaded organic phase and back-extraction agent obtained in step (2) are respectively pumped to the inlet of the microchannel reactor (the same model as the microchannel reactor in step (2)) by metering pumps, and then mixed in the microchannel reactor for back-extraction to obtain back-extraction liquid and regenerated organic phase. After detection, the composition of the back-extraction liquid is: Co 2+ 59.8g / L, Ni 2+ 101.5g / L, Mn 2+ 0.02 g / L and Cu 2+ 0.01g / L, Co 2+ Ni 2+ The resolution was >99.5%; the back-extraction agent was 1.5 mol / L hydrochloric acid, and the volumetric flow rate ratio (A / O) of the back-extraction agent to the supported organic phase was 3:1; the back-extraction temperature was 50℃, the time was 15s, the total flow rate was 150mL / min, the microchannel volume was 30mL, and 30mL / 150mL / min = 12s. In actual operation, there were slight fluctuations, so the time was set to 15s. (4) The back-extraction solution obtained in step (3) is mixed with a sodium sulfide solution with a concentration of 0.8 mol / L (the pH value of the mixture is 4.5), and then precipitated under stirring. After filtration, the solution is evaporated and concentrated to Co at 90°C and a vacuum of 0.07 MPa.2+ and Ni 2+ The total concentration was 90 g / L. Cobalt and nickel were then separated using D851 chelating resin to obtain cobalt-containing and nickel-containing electrolytes. Finally, the cobalt-containing and nickel-containing electrolytes were electrolytically deposited to obtain high-purity cobalt and high-purity nickel, respectively. The anode for the electrolytic deposition was a titanium plate, the cathode was a stainless steel plate, and the electrolytes were the cobalt-containing and nickel-containing electrolytes, respectively. The electrolytic deposition temperature was 55℃, and the current density was 250 A / m. 2 The time is 10 hours; the regenerated organic phase is allowed to stand and separate into layers, and the aqueous phase is removed to obtain the purified organic phase (the solvent recovery rate is 94.2% due to organic phase loss caused by emulsification).

[0068] The purity of the high-purity cobalt and high-purity nickel obtained in Comparative Example 3 was analyzed by GD-MS (glow discharge mass spectrometry). The purity of high-purity cobalt was 99.998% (Mn 1.2ppm, Cu 1.0ppm), and the purity of high-purity nickel was 99.998% (Mn 1.5ppm, Cu 1.3ppm), neither of which met the requirements of 5N grade.

[0069] By comparing Examples 1-3 with Comparative Examples 1-3, it can be seen that the method provided by the present invention, by using ([BMIM]PF6+DNNSA+microchannel reactor), is significantly superior to traditional processes and single improved processes in terms of separation coefficient, solvent recovery rate and product purity, and can stably prepare 5N grade high-purity cobalt nickel products.

[0070] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for purifying 5N grade high-purity cobalt-nickel using ionic liquid-enhanced extraction, characterized in that, Includes the following steps: (1) After mixing the Co / Ni symbiotic ore and sulfuric acid solution, filter to obtain leachate, and then adjust the pH value of the leachate to 2.0~3.0 to obtain pretreated aqueous raw material; (2) The pretreated aqueous raw material and organic phase obtained in step (1) are mixed in a microchannel reactor and then extracted to obtain a loaded organic phase and raffinate; the organic phase is composed of [BMIM]PF6 ionic liquid and DNNSA; the volume flow ratio of the pretreated aqueous raw material and the organic phase is (1~3):1; (3) The loaded organic phase and the back-extraction agent obtained in step (2) are mixed in a back-extraction microchannel reactor and then back-extracted to obtain back-extraction liquid and regenerated organic phase; (4) The back-extraction solution obtained in step (3) is purified and concentrated by evaporation to obtain a cobalt-nickel electrolyte, which is then electrolytically deposited to obtain a high-purity cobalt-nickel alloy. Alternatively, the back-extraction solution obtained in step (3) can be purified and concentrated by evaporation, and then cobalt and nickel can be separated by ion exchange resin to obtain a cobalt-containing electrolyte and a nickel-containing electrolyte. Finally, the cobalt-containing electrolyte and the nickel-containing electrolyte can be electrolytically deposited to obtain high-purity cobalt and high-purity nickel.

2. The method according to claim 1, characterized in that, The particle size of the Co / Ni symbiotic ore in step (1) is ≤74μm.

3. The method according to claim 1, characterized in that, In step (1), the concentration of the sulfuric acid solution is 1.5~2.5 mol / L; the ratio of the volume of the sulfuric acid solution to the mass of the Co / Ni symbiotic ore is (3~5) mL:1g.

4. The method according to claim 1, characterized in that, In step (1), the pretreated aqueous raw material contains Co 2+ The concentration is 10~20g / L, Ni 2+ The concentration is 20~30g / L, Mn 2+ The concentration is 1~5 g / L, Cu 2+ The concentration is 0.5~2g / L.

5. The method according to claim 1, characterized in that, In step (2), the mass of DNNSA is 5-15% of the mass of the [BMIM]PF6 ionic liquid.

6. The method according to claim 1, characterized in that, The extraction temperature in step (2) is 30~45℃ and the extraction time is 10~30s; the contact mode between the pretreated aqueous raw material and the organic phase in the microchannel reactor is cross-flow contact mode, counter-flow contact mode or co-flow contact mode.

7. The method according to claim 1, characterized in that, In step (3), the back-extraction agent is hydrochloric acid, and the concentration of hydrochloric acid is 1~2 mol / L; the volume flow rate ratio of the back-extraction agent to the supported organic phase is (2~4):

1.

8. The method according to claim 1, characterized in that, In step (3), the temperature for back-extraction is 40~55℃ and the time for back-extraction is 15~40s.

9. The method according to claim 1, characterized in that, In step (3), the regenerated organic phase is subjected to vacuum distillation. The vacuum degree of the vacuum distillation is 0.08~0.1MPa, the temperature of the vacuum distillation is 60~80℃, and the time of the vacuum distillation is 10~20min.

10. The method according to claim 1, characterized in that, In step (4), the anode for electrolytic deposition is a titanium plate, the cathode for electrolytic deposition is a stainless steel plate, the electrolytic deposition temperature is 50~60℃, and the electrolytic deposition current density is 200~300A / m. 2 The electrolytic deposition time is 8~12h.