Method for preparing high-purity electrodeposited nickel by chlorination leaching of nickel-containing sulfide materials

Abstract

The application discloses a method for preparing high-purity electrodeposited nickel by chlorination leaching of nickel-containing sulfide materials, and belongs to the technical field of hydrometallurgy. The method uses a salting-out mother liquor as a chlorination leaching medium, and chlorination leaching is performed on the nickel-containing sulfide materials by using chlorine gas. Under the condition of an oxidizing agent and a high concentration of chloride ions, copper, iron, cobalt, lead, zinc and other ions are prone to form complex anions, and nickel ions or nickel-chlorine cations are also formed. After the leaching slurry is subjected to solid-liquid separation, a chloride ion regulator is added to the leaching solution, and after temperature rising and holding, temperature dropping and crystallization, and solid-liquid separation, nickel chloride crystals and a crystallization mother liquor are obtained. The method has the advantages of a relatively short process, good impurity separation effect, high product quality, recycling of chlorine resources, and strong industrial applicability, and the obtained electrodeposited nickel meets the requirements of the Ni9999 grade electrolytic nickel in GB / T 6516-2025, and the total nickel recovery rate is not less than 99%.

Description

Technical Field

[0001] This invention belongs to the field of hydrometallurgical technology, specifically relating to a method for preparing high-purity electrolytic nickel by chlorination leaching of nickel-containing sulfide materials. Background Technology

[0002] Nickel is an important non-ferrous metal widely used in stainless steel, alloy materials, electroplating, new energy batteries, and high-temperature alloys. With the development of high-end equipment manufacturing, new energy, and aerospace industries, the market demand for high-purity nickel and high-quality electrolytic nickel is constantly increasing.

[0003] Nickel-containing sulfide materials have a wide range of sources, including nickel sulfide concentrate, nickel matte, nickel sulfide smelting intermediates, and secondary nickel sulfide resources. Compared to pyrometallurgical processes, hydrometallurgical processes have the advantages of milder reaction conditions, greater process selectivity, and stronger controllability, making it easier to leach, separate, and enrich valuable metals. Currently, most hydrometallurgical treatments of nickel-containing sulfide materials use a sulfuric acid system. Although this system is relatively mature, when preparing high-quality cathode nickel, the leachate usually requires multiple stages of neutralization precipitation, solvent extraction, ion exchange, or other deep purification treatments, resulting in a long process flow, a large number of reagents, and high wastewater treatment pressure.

[0004] To overcome the aforementioned shortcomings of the sulfuric acid system, the chlorination system has gradually attracted attention. Compared with the sulfuric acid system, the chlorination system has a stronger oxidative leaching ability for nickel-containing sulfide materials under the action of oxidants such as chlorine gas. The resulting chloride solution has high conductivity and can be effectively connected with the subsequent chlorination electrowinning process. It exhibits better process adaptability to nickel-containing sulfide materials in different occurrence forms and provides favorable conditions for continuous operation of leaching, purification and electrowinning processes as well as the recycling of chlorine resources.

[0005] However, after chlorination leaching, nickel-containing sulfide materials typically leave behind impurities such as iron, copper, and cobalt in the leachate. If the leachate enters the electrowinning process directly without effective purification, these impurities can be entrained, co-deposited, or interfere with the normal growth of nickel grains during cathode deposition, leading to a decrease in the purity of the cathode nickel and problems such as rough surface, nodules, and uneven edge deposition. Existing purification methods for chlorination systems mostly employ precipitation, solvent extraction, ion exchange, or multi-stage deep purification, which generally suffer from drawbacks such as long purification processes, numerous operational steps, and high operating costs. Furthermore, if the chlorine gas generated at the anode during chlorination electrowinning cannot be effectively recovered and utilized, it will further increase the treatment load of chlorine-containing tail gas and the consumption of purchased oxidants.

[0006] Therefore, there is an urgent need to develop a method for treating nickel-containing sulfide materials that has a shorter process, stable purification effect, and is suitable for electrowinning in chlorination systems. This is of great significance for shortening the process flow, reducing purification costs, stabilizing the quality of the pre-electrowinning solution, and improving the quality of the cathode nickel plate. Summary of the Invention

[0007] In view of the defects and shortcomings of the existing technology, the purpose of this invention is to provide a simple, clean and environmentally friendly method for preparing high-purity electrowinning nickel by chlorination leaching of nickel-containing sulfide materials, which is suitable for industrial applications.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] This invention provides a method for preparing high-purity electrolytic nickel by chlorination leaching of nickel-containing sulfide materials, comprising the following steps:

[0010] Step (1): Mix the nickel-containing sulfide material with the chlorine-containing leaching medium to form a suspension, and introduce chlorine gas into the suspension to perform chlorination leaching to obtain a chlorinated leaching slurry;

[0011] Step (2): The chlorinated leaching slurry obtained in step (1) is subjected to solid-liquid separation to obtain primary leaching solution and primary leaching residue; the primary leaching residue is subjected to secondary leaching with hydrochloric acid, and after solid-liquid separation, secondary leaching solution and secondary leaching residue are obtained. The secondary leaching solution is returned to step (1) as a component of the chlorinated leaching medium for recycling.

[0012] Step (3): Add a chloride ion regulator to the first leaching solution obtained in step (2) to obtain a salting-out mixture; heat the salting-out mixture and keep it at a constant temperature, then cool it down for crystallization and solid-liquid separation to obtain nickel chloride crystals and salting-out mother liquor. Return all or part of the salting-out mother liquor to step (1) and use it as a component of the chloride-containing leaching medium.

[0013] Step (4): After washing the nickel chloride crystals obtained in step (3), dissolve them and adjust the nickel ion concentration, chloride ion concentration and acidity in the resulting solution to obtain the nickel chloride electrowinning solution;

[0014] Step (5): The nickel chloride pre-electrodeionization solution obtained in step (4) is sent into the electrodeionization tank for electrodeionization. Electrodeionized nickel is obtained at the cathode and chlorine gas is generated at the anode. The chlorine gas is collected and returned to step (1) for recycling.

[0015] This invention provides a method for preparing high-purity electrowinning nickel by chlorination leaching of nickel-containing sulfide materials. The method primarily uses the salt-out mother liquor obtained from salt-out crystallization as the chlorination leaching medium and chlorine gas as the oxidant to treat the nickel-containing sulfide materials. Chlorine gas can oxidize nickel in its sulfide or other leaching forms, allowing nickel and some associated metals to enter the chlorination system solution. The primary leaching solution obtained after solid-liquid separation contains components such as Ni, Fe, Cu, and Co. In the high-chlorine system, impurities such as iron, copper, and cobalt can form chloride complexes or chloride anions, exhibiting strong solution stability. Although nickel can also form nickel-chloride complexes, the apparent solubility of nickel chloride can be reduced by adding a chloride ion regulator to increase the chloride ion concentration in the mixed solution, utilizing the common ion effect and increased solution ionic strength. Therefore, by heating and homogenizing and controlling cooling for crystallization, nickel chloride is more likely to reach supersaturation and precipitate as nickel chloride crystals during the cooling process. Meanwhile, impurity ions such as Fe, Cu, and Co tend to form chloride complexes or maintain high solubility in the high-chlorine system, thus remaining more in the salting-out mother liquor. This achieves the separation of nickel from impurity elements, resulting in a stable nickel chloride electrowinning solution with low impurity content after dissolution and liquid conditioning. During the chloride electrowinning process, Ni... 2+ At the cathode, electrons are gained and deposited to form metallic nickel, Cl - The titanium-based coated insoluble anode loses electrons and generates chlorine gas. The chlorine gas generated at the anode is returned to the chlorination leaching process and recycled as an oxidant.

[0016] In a preferred embodiment, the nickel-containing sulfide material is selected from at least one of nickel sulfide concentrate, nickel matte, nickel-containing sulfide smelting intermediates, and nickel-containing sulfide secondary resources.

[0017] In a preferred embodiment, the chlorine-containing leaching medium comprises hydrochloric acid and a soluble chloride salt; the soluble chloride salt is selected from at least one of nickel chloride, sodium chloride, potassium chloride, and ammonium chloride, and the chlorine-containing leaching medium contains Cl... - The total chloride ion concentration is 100–450 g / L, preferably 180–350 g / L; the free acid concentration, calculated as HCl, is 0.5–4.0 mol / L, preferably 1.0–3.0 mol / L.

[0018] In the method of this invention, before the salt-out mother liquor produced by this process is formed during initial startup, a pre-prepared chlorine-containing leaching medium is used. This chlorine-containing leaching medium contains at least hydrochloric acid and a soluble chloride salt, preferably hydrochloric acid and nickel chloride, and sodium chloride, potassium chloride, or ammonium chloride may be added according to the composition of the nickel-containing sulfide material and the leaching requirements. Hydrochloric acid is used to provide the acidity required for dissolution, promoting the dissolution of the nickel-containing components; nickel chloride and other soluble chloride salts are used to establish suitable chloride ion concentration and ionic strength, and to keep the main components of the chlorine-containing leaching medium within the aforementioned parameter range during initial startup, approximating the salt-out mother liquor during stable operation.

[0019] During continuous industrial operation, the salting-out mother liquor obtained from the previous batch of salting-out crystallization is used as the base liquid for the chlorine-containing leaching medium. The returned secondary leaching liquid is added together, and at least one of hydrochloric acid, sodium chloride, potassium chloride, or ammonium chloride is added according to the acidity and chloride ion concentration to maintain the conditions required for chlorination leaching and metal chloride complexation reaction.

[0020] In a preferred embodiment, the liquid-solid mass ratio of the chlorine-containing leaching medium to the nickel-containing sulfide material is (4~12):1, and more preferably (6~10):1.

[0021] In a preferred embodiment, the amount of chlorine gas introduced is 1.0 to 2.0 times the theoretical amount of chlorine gas required for chlorination leaching.

[0022] The theoretical chlorine amount described in this invention is based on the content and initial valence state of nickel, iron, copper, cobalt, sulfides and other reducing components that can be leached by chlorination in nickel-containing sulfide materials, as well as the target valence state and preset reaction products reached by each component after leaching. The chlorine stoichiometry is calculated according to the conservation of electrons. The chlorine amount is controlled at 1.0 to 2.0 times the theoretical amount, which can balance the chlorination leaching effect and chlorine utilization efficiency.

[0023] In a preferred embodiment, the chlorination leaching temperature is 60-110℃, more preferably 80-105℃; and the chlorination leaching time is 1-5 h, more preferably 2-5 h.

[0024] In a preferred embodiment, the concentration of nickel chloride (calculated as NiCl2) in the primary leachate is 80-400 g / L, more preferably 150-300 g / L, the concentration of Fe is 0.1-40 g / L, the concentration of Cu is 0.05-20 g / L, and the concentration of Co is 0.05-20 g / L.

[0025] Experiments have shown that unreacted nickel-containing components may remain in the primary leaching residue, and acid-soluble nickel-containing phases may also be present, which are encapsulated by sulfur, silicates or other solid phases. Secondary leaching with hydrochloric acid can further dissolve the residual nickel-containing components and reduce the loss of nickel with the secondary leaching residue. The resulting secondary leaching solution is returned to step (1) to recover the nickel, hydrochloric acid and chloride components.

[0026] Preferably, the concentration of hydrochloric acid used in the secondary leaching is 3–8 mol / L, more preferably 4–6 mol / L. Experiments have shown that using hydrochloric acid of the above concentration for secondary leaching of the primary leaching residue yields the best leaching effect. If the hydrochloric acid concentration is below 3 mol / L, the solution acidity may be insufficient, making it difficult to fully dissolve the residual nickel-containing phases in the primary leaching residue. If the hydrochloric acid concentration is above 8 mol / L, the nickel leaching rate improvement is limited, while increasing hydrochloric acid consumption, equipment corrosion, and the acidity adjustment load of the return solution, and may promote excessive leaching of some impurities.

[0027] Preferably, the liquid-to-solid mass ratio of hydrochloric acid used in the secondary leaching to the primary leaching residue is (4-12):1. Experiments have shown that the above-mentioned liquid-to-solid mass ratio of hydrochloric acid to primary leaching residue results in the best leaching effect. When the liquid-to-solid mass ratio is lower than 4:1, the contact between the primary leaching residue and hydrochloric acid is insufficient, and the slurry flow and mass transfer conditions are poor. When the liquid-to-solid mass ratio is higher than 12:1, although it can improve the solid-liquid contact, it will cause the volume of the secondary leaching solution to be too large, diluting the nickel concentration returned to the leaching system and increasing the solution circulation and subsequent processing load.

[0028] Preferably, the secondary leaching temperature is 60–95°C, and the secondary leaching time is 1–5 h.

[0029] In a preferred embodiment, the chloride ion regulator is selected from at least one of hydrochloric acid, sodium chloride, potassium chloride, and ammonium chloride.

[0030] In a preferred embodiment, the salting-out mixture contains Cl... - The total chloride ion concentration in the liquid phase is calculated to be 80~450 g / L, preferably 320~450 g / L.

[0031] Experiments have shown that it is necessary to effectively control the concentration of chloride ions in the salting-out mixture. If the concentration is too low, the common ion effect and salting-out effect are insufficient, and nickel chloride will not be able to reach supersaturation, resulting in a decrease in crystallization yield. During the cooling process, nickel chloride will not be able to reach supersaturation, resulting in incomplete precipitation. If the concentration is too high, it will lead to the precipitation of other impurities.

[0032] In a preferred embodiment, the salting-out mixture is heated to 45~95℃ and held at that temperature for 10~60 min, and then cooled to 10~35℃ at a cooling rate of 0.2~5.0℃ / min for crystallization.

[0033] As the number of cycles of the salting-out mother liquor increases, impurities such as Fe, Cu, and Co that do not precipitate with nickel chloride crystals will gradually accumulate in the salting-out mother liquor. In actual operation, based on the accumulation of impurities in the salting-out mother liquor obtained from solid-liquid separation, if the impurity concentration reaches the preset open-circuit threshold, a portion of the circulating salting-out mother liquor is extracted for open-circuit impurity removal. After impurity removal, it is returned to step (1) as a component of the chlorine-containing leaching medium for recycling. The portion that is not extracted is returned to step (1) as a component of the chlorine-containing leaching medium for recycling. If the impurity concentration does not reach the preset open-circuit threshold, all of it is returned to step (1) as a component of the chlorine-containing leaching medium for recycling.

[0034] In a preferred embodiment, the nickel chloride crystals are washed with a washing solution, and the washed nickel chloride crystals are dissolved with at least one of water, hydrochloric acid and the nickel chloride electrowinning solution obtained after electrowinning in step (5), and the nickel ion concentration, nickel ion concentration and acidity are adjusted to obtain the nickel chloride pre-electrowinning solution.

[0035] In a further preferred embodiment, the washing solution is selected from at least one of a saturated nickel chloride solution, a hydrochloric acid solution, and a sodium chloride solution, and the liquid-solid mass ratio of the washing solution to the nickel chloride crystals is (0.5~4.0):1.

[0036] In a preferred embodiment, the nickel ion concentration in the nickel chloride pre-electrodeionizing solution is 60–260 g / L, the chloride ion concentration is 100–320 g / L, and the pH is 1.0–2.8. Experiments have shown that controlling the parameters of the nickel chloride pre-electrodeionizing solution within these ranges yields the optimal electrodeionizing effect. When the nickel ion concentration is below 60 g / L, concentration polarization and hydrogen evolution side reactions easily occur, reducing current efficiency and unit tank production capacity. When the concentration is above 260 g / L, the solution viscosity and salt load increase, affecting mass transfer and cathode deposition uniformity, and increasing the risk of solution crystallization or salting out. When the chloride ion concentration is below 100 g / L, the conductivity of the electrodeionizing solution decreases, the tank voltage and energy consumption increase, and the anodic chloride evolution reaction may be affected. When the concentration is above 320 g / L, equipment corrosion and chlorine escape loads increase, and the higher ionic strength may affect the cathode deposition morphology. When the pH is below 1.0, the hydrogen evolution reaction at the cathode is enhanced, which may reduce the nickel current efficiency and affect the compactness of the nickel at the cathode. When the pH is above 2.8, local cathode areas are prone to hydrolysis of nickel and impurity metal ions or formation of basic salts, resulting in cathode inclusions, surface roughness and nodules.

[0037] In a preferred embodiment, during electrodeposition, the electrodeposition temperature is controlled at 50~75 ℃, and the cathode current density is 220~340 A / m. 2 The cell voltage is 3.0~5.2 V, and the electrowinning time is 8~60 h.

[0038] In a preferred embodiment, during electrowinning, the anode is a titanium-based coated insoluble anode, and the cathode is a nickel starting electrode.

[0039] The chlorine gas generated at the anode is collected, washed and / or dried and returned to the chlorination leaching process. The nickel chloride electrowinning solution generated during the electrowinning process is used to dissolve nickel chloride crystals and to prepare the nickel chloride electrowinning solution.

[0040] The preferred scheme yields electrolytic nickel that meets the requirements for Ni9999 grade electrolytic nickel in GB / T 6516-2025, with a total nickel recovery rate of ≥99%.

[0041] Principles and advantages

[0042] This invention uses a chlorine-containing leaching medium containing acidic components and soluble chloride salts to treat nickel-containing sulfide materials, and uses chlorine gas as an oxidant to allow nickel and some associated metals to enter the chlorination system solution.

[0043] The resulting primary leaching solution contains components such as Ni, Fe, Cu, and Co. Adding a chloride ion regulator to the primary leaching solution increases the chloride ion concentration and ionic strength of the system. Under the influence of the common ion effect and salting-out, the apparent solubility of nickel chloride decreases. Heating and maintaining the temperature ensures a homogeneous composition of the salting-out mixture, and controlled cooling causes nickel chloride to reach supersaturation, precipitating as hydrated nickel chloride crystals. Impurities such as iron, copper, and cobalt remain primarily in the salting-out mother liquor as chloride complexes, thus achieving the separation of nickel from associated impurities.

[0044] The obtained nickel chloride crystals, after dissolution and solution conditioning, form a nickel chloride electrowinning solution with stable composition and low impurity content. During the nickel chloride electrowinning process, Ni... 2+ At the cathode, electrons are gained and deposited to form metallic nickel, Cl - The titanium-based coated insoluble anode loses electrons and generates chlorine gas. The chlorine gas generated at the anode is returned to the chlorination leaching process and recycled as an oxidant.

[0045] Compared with existing technologies, the method provided by this invention can effectively separate nickel from impurity elements such as iron, copper, and cobalt, reducing the impact of impurities on the electrodeposition process and the quality of cathode nickel; it can also achieve the recycling of nickel and chlorine resources, reducing reagent consumption and chlorine-containing wastewater discharge. This invention has the advantages of simple process, recyclable chlorine gas, and high product quality. The obtained cathode nickel meets the requirements of Ni9999 grade in GB / T 6516-2025, with a total nickel recovery rate of ≥99%. Attached Figure Description

[0046] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0047] To facilitate understanding of the present invention, the invention will be further described below in conjunction with the accompanying drawings and embodiments, but these embodiments should not be used to interpret any limitation on the scope of patent protection of the present invention.

[0048] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0049] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0050] The nickel-containing sulfide material used in this embodiment of the invention is nickel sulfide concentrate, whose main elemental composition is: Ni 28.60%, Fe 24.35%, Cu 8.75%, Co 0.56%, S 29.80%, MgO 2.15%, SiO2 1.85%. The nickel sulfide concentrate is subjected to chlorination leaching, solid-liquid separation, secondary leaching of primary leaching residue, salting-out purification of primary leaching solution, washing of nickel chloride crystals, crystal dissolution and liquid conditioning, and chlorination electrowinning treatment to obtain high-purity electrowinning nickel.

[0051] Example 1 is an implementation method for the first start-up of the process of the present invention, using a pre-prepared chlorine-containing solution as the chlorine-containing leaching medium; Examples 2 and 3 are implementation methods for the stable operation of the system in a cyclical manner, using the previous batch of salting-out mother liquor and the returned secondary leaching liquid to form the chlorine-containing leaching medium.

[0052] Example 1:

[0053] During the initial startup, a chlorine-containing leaching medium was pre-prepared using nickel chloride hexahydrate, hydrochloric acid, and sodium chloride. The chlorine-containing leaching medium contained nickel chloride at a concentration of 120 g / L (based on NiCl2), hydrochloric acid at 2.0 mol / L, and sodium chloride at 140 g / L. - The calculated total chloride ion concentration in the liquid phase is approximately 220 g / L. During preparation, nickel chloride hexahydrate and sodium chloride are dissolved in water, then hydrochloric acid is added and mixed thoroughly to obtain the chlorine-containing leaching medium for initial startup.

[0054] Take 100 g of nickel sulfide concentrate and add the chlorine-containing leaching medium used for initial start-up, controlling the liquid-to-solid mass ratio at 8:1. Leach under stirring conditions, with chlorine gas introduced at a leaching temperature of 95 ℃ and a leaching time of 4 h. The chlorine gas introduction rate is 1.5 times the theoretical chlorine gas amount. After leaching, perform solid-liquid separation to obtain primary leaching solution and primary leaching residue.

[0055] The primary leaching residue was subjected to a secondary leaching using 5 mol / L hydrochloric acid at a salt-to-solid mass ratio of 6:1, a leaching temperature of 85 ℃, and a leaching time of 2 h. After leaching, solid-liquid separation was performed, and the resulting secondary leachate was recycled to the next batch of chlorination leaching process.

[0056] The concentrations of NiCl2, Fe, Cu, and Co in the obtained primary leachate were 205 g / L, 21.6 g / L, 7.8 g / L, and 0.68 g / L, respectively. Sodium chloride was added to the primary leachate as a chloride ion regulator until the total Cl- concentration in the salting-out mixture was reduced. - When the concentration reaches 430 g / L, the temperature is raised to 82 ℃ and held for 50 min, then cooled to 25 ℃ at a rate of 2.0 ℃ / min and crystallized for 60 min. Solid-liquid separation yields nickel chloride crystals and crystallization mother liquor. The crystallization mother liquor is returned to the next batch of chlorination leaching process for recycling.

[0057] Nickel chloride crystals were washed with a saturated nickel chloride solution, dissolved in water, and adjusted with dilute hydrochloric acid to obtain a Ni concentration of 120 g / L and a Cl concentration of [missing value]. - Nickel chloride pre-electrowinning solution with a concentration of 145 g / L and a pH of 2.0.

[0058] The electrolyte before electrodeposition was fed into the electrodeposition cell, and the electrodeposition was carried out at 60 °C and a cathode current density of 290 A / m. 2 Electrowinning was carried out for 36 hours under a cell voltage of 4.1 V. The resulting electrowinning nickel had a Ni+Co mass fraction of 99.992%, and the contents of Co, Fe, Cu, Zn, As, and Pb were 0.0032%, 0.0015%, 0.0010%, 0.0007%, 0.0005%, and 0.0002%, respectively, meeting the requirements for Ni9999 grade electrolytic nickel in GB / T 6516-2025. The chlorine gas generated at the anode was collected, washed, and returned to the chlorination leaching process. The electrowinning return solution was used for the subsequent dissolution of nickel chloride crystals and the preparation of the pre-electrowinning solution.

[0059] Example 2:

[0060] 100 g of nickel sulfide concentrate was taken, and the mother liquor returned from the previous batch was used as the chlorination leaching medium. The liquid-solid mass ratio of the mother liquor to the nickel sulfide concentrate was controlled at 7:1. The chlorination leaching temperature was 105 ℃, the leaching time was 3 h, and the chlorine gas flow rate was 1.7 times the theoretical requirement. After leaching, the obtained chlorination slurry was subjected to solid-liquid separation to obtain primary leaching solution and primary leaching residue.

[0061] The residue from the first leaching was leached with 6 mol / L hydrochloric acid at 90 °C for 1.5 h, with a liquid-to-solid mass ratio of 5:1. After the second leaching, solid-liquid separation was performed, and the resulting second leaching solution was returned to the chlorination leaching process.

[0062] The concentrations of NiCl2, Fe, Cu, and Co in the primary leachate were 218 g / L, 19.8 g / L, 8.4 g / L, and 0.75 g / L, respectively. Potassium chloride was added as a chloride ion regulator until the total Cl- concentration in the salting-out mixture was reduced. - When the concentration reaches 380 g / L, the temperature is raised to 85 ℃ and held for 60 min, then cooled to 20 ℃ at a rate of 1.5 ℃ / min, and crystallized for 80 min. The resulting mother liquor is returned to the next batch of chlorination leaching process.

[0063] Nickel chloride crystals were washed and dissolved and adjusted with dilute hydrochloric acid to obtain a Ni concentration of 110 g / L and a Cl concentration of [missing value]. - The pre-electrowinning solution had a concentration of 130 g / L and a pH of 1.8. The cathode current density was 300 A / m at 65 °C. 2 Electrowinning was carried out for 40 hours under a cell voltage of 4.3 V. The chlorine gas generated at the anode was collected, washed, and dried before being returned to the chlorination leaching process.

[0064] The obtained electrolytic nickel has a Ni+Co mass fraction of 99.993%, and the contents of Co, Fe, Cu, Zn, As and Pb are 0.0030%, 0.0014%, 0.0009%, 0.0007%, 0.0005% and 0.0002%, respectively, which meets the requirements of Ni9999 grade electrolytic nickel in GB / T 6516-2025, and the total nickel recovery rate is not less than 99.1%.

[0065] Example 3:

[0066] 100 g of nickel sulfide concentrate was taken, and the mother liquor returned from the previous batch was used as the chlorination leaching medium. The liquid-solid mass ratio of the mother liquor to the nickel sulfide concentrate was controlled at 9:1. The chlorination leaching temperature was 90 ℃, the leaching time was 5 h, and the chlorine gas flow rate was 1.4 times the theoretical requirement. After leaching, solid-liquid separation was performed to obtain primary leaching solution and primary leaching residue.

[0067] The primary leaching residue was leached with 4 mol / L hydrochloric acid at 80 °C for 3 h with a liquid-to-solid mass ratio of 8:1. After the secondary leaching, solid-liquid separation was performed to obtain secondary leaching solution and secondary leaching residue. The obtained secondary leaching solution was returned to the chlorination leaching process.

[0068] The concentrations of NiCl2, Fe, Cu, and Co in the primary leachate were 198 g / L, 23.4 g / L, 6.9 g / L, and 0.61 g / L, respectively. Sodium chloride and ammonium chloride were added as a composite chloride ion regulator until the total Cl- concentration in the salting-out mixture was reduced. -When the concentration reaches 320 g / L, the temperature is raised to 80 ℃ and held for 40 min, then cooled to 15 ℃ at a rate of 1.0 ℃ / min, and crystallized for 90 min. The resulting mother liquor is returned to the next batch of chlorination leaching process.

[0069] Nickel chloride crystals were washed and dissolved in the electrodeposition return solution, and then diluted with dilute hydrochloric acid to adjust the solution, yielding a Ni concentration of 115 g / L and a Cl concentration of [missing value]. - The pre-electrowinning solution had a concentration of 140 g / L and a pH of 2.2. The cathode current density was 280 A / m at 58 °C. 2 Electrowinning was carried out for 48 hours under a cell voltage of 4.0 V, and the chlorine gas generated at the anode was returned to the chlorination leaching process.

[0070] The obtained electrolytic nickel has a Ni+Co mass fraction of 99.991%, and the contents of Co, Fe, Cu, Zn, As, and Pb are 0.0035%, 0.0017%, 0.0012%, 0.0008%, 0.0006%, and 0.0003%, respectively, meeting the requirements for Ni9999 grade electrolytic nickel in GB / T 6516-2025. Through continuous operation and cumulative material balance calculations, the total nickel recovery rate is not less than 99%.

[0071] Comparative Example 1:

[0072] Following the method of Example 2, the mother liquor returned from the previous batch was used as the chlorination leaching medium to perform chlorination leaching, solid-liquid separation, and secondary leaching on 100 g of nickel sulfide concentrate. However, the resulting primary leaching solution was not subjected to salting-out purification; instead, the Ni and Cl concentrations were directly adjusted. - The concentration and pH were electrowinning according to the electrowinning conditions of Example 2.

[0073] The resulting electrolytic nickel contained 99.6% Ni+Co by mass, and the contents of Co, Fe, Cu, Zn and Pb were 0.018%, 0.0065%, 0.0048%, 0.0018% and 0.0007%, respectively, which did not meet the requirements for Ni9999 grade electrolytic nickel in GB / T 6516-2025.

[0074] Comparative Example 2:

[0075] Following the method of Example 2, the mother liquor returned from the previous batch was used as the chlorination leaching medium to perform chlorination leaching, secondary leaching, and salting-out purification on 100 g of nickel sulfide concentrate. However, after washing and dissolving the obtained nickel chloride crystals, the Ni concentration in the resulting nickel chloride electrowinning solution was adjusted to 110 g / L and the Cl concentration to 110 g / L. - The concentration was 130 g / L, and the pH was adjusted only to 3.2.

[0076] The electrolyte solution was electrolyzed under the conditions described in Example 2. The resulting electrolyzed nickel contained 99.8% Ni+Co by mass, and 0.0035% Fe and 0.0022% Cu, respectively. This did not meet the requirements for Ni9999 grade electrolytic nickel in GB / T 6516-2025, and the total nickel recovery rate was 96.8%.

[0077] Comparative Example 3:

[0078] 100 g of nickel sulfide concentrate was treated according to the method in Example 2, except that potassium chloride was added to the resulting primary leaching solution as a chloride ion regulator, so that the salting-out mixture contained Cl- ions. - The calculated total chloride ion concentration in the liquid phase reached 500 g / L, which is higher than 380 g / L in Example 2 and exceeds the upper limit of 450 g / L specified in this invention. Except for the total chloride ion concentration in the salting-out mixture, the leaching, secondary leaching, and salting-out crystallization conditions were the same as in Example 2.

[0079] The salting-out mixture was heated to 85 °C and held at that temperature for 60 min, then cooled to 12 °C at a rate of 1.5 °C / min, and crystallized at 12 °C for 80 min. After crystallization, solid-liquid separation was performed to obtain nickel chloride crystals and salting-out mother liquor. The obtained nickel chloride crystals had a finer particle size, and the entrainment of salting-out mother liquor on the crystal surface and in the intercrystalline spaces was more pronounced than in Example 2.

[0080] The obtained nickel chloride crystals were washed with a saturated nickel chloride solution. The washed nickel chloride crystals were then dissolved and adjusted with water and dilute hydrochloric acid to obtain Ni. 2+ Concentration of 110 g / L, Cl - A nickel chloride pre-electrodeionization solution with a concentration of 130 g / L and a pH of 1.8 was prepared. The resulting nickel chloride pre-electrodeionization solution was fed into an electrodeposition cell, and the electrodeposition temperature was 65 °C and the cathode current density was 300 A / m. 2 Electrowinning was carried out for 40 hours under a cell voltage of 4.3 V.

[0081] The obtained electrolytic nickel had a Ni+Co mass fraction of 99.982%, and the contents of Co, Fe, Cu, Zn, As and Pb were 0.0041%, 0.0060%, 0.0036%, 0.0011%, 0.0007% and 0.0004%, respectively. This did not meet the requirements of Ni9999 grade electrolytic nickel in GB / T 6516-2025, and the total nickel recovery rate was 98.8%.

Claims

1. A method for preparing high-purity electrowinning nickel by chlorination leaching of nickel-containing sulfide materials, characterized in that: Includes the following steps: Step (1): Mix the nickel-containing sulfide material with the chlorine-containing leaching medium to form a suspension, and introduce chlorine gas into the suspension to perform chlorination leaching to obtain a chlorinated leaching slurry; Step (2): The chlorinated leaching slurry obtained in step (1) is subjected to solid-liquid separation to obtain primary leaching solution and primary leaching residue; the primary leaching residue is subjected to secondary leaching with hydrochloric acid, and after solid-liquid separation, secondary leaching solution and secondary leaching residue are obtained. The secondary leaching solution is returned to step (1) as a component of the chlorinated leaching medium for recycling. Step (3): Add chloride ion regulator to the first leaching solution obtained in step (2) to obtain salting-out mixture; heat the salting-out mixture and keep it at a constant temperature, then cool it down for crystallization and solid-liquid separation to obtain nickel chloride crystals and salting-out mother liquor. Return all or part of the salting-out mother liquor to step (1) and use it as a component of the chloride-containing leaching medium. Step (4): After washing the nickel chloride crystals obtained in step (3), dissolve them and adjust the nickel ion concentration, chloride ion concentration and acidity in the resulting solution to obtain the nickel chloride electrowinning solution; Step (5): The nickel chloride pre-electrodeionization solution obtained in step (4) is sent into the electrodeionization tank for electrodeionization. Electrodeionized nickel is obtained at the cathode and chlorine gas is generated at the anode. The chlorine gas is collected and returned to step (1) for recycling.

2. The method for preparing high-purity electrowinning nickel by chlorination leaching of nickel-containing sulfide materials according to claim 1, characterized in that: The nickel-containing sulfide material is selected from at least one of nickel sulfide concentrate, nickel matte, nickel-containing sulfide smelting intermediates, and nickel-containing sulfide secondary resources; The chlorine-containing leaching medium comprises hydrochloric acid and a soluble chloride salt, wherein the soluble chloride salt is selected from at least one of nickel chloride, sodium chloride, potassium chloride, and ammonium chloride; In the chlorine-containing leaching medium, Cl - The total chloride ion concentration is 100–450 g / L; the free acid concentration, calculated as HCl, is 0.5–4.0 mol / L. The liquid-solid mass ratio of the chlorine-containing leaching medium to the nickel-containing sulfide material is 4~12:

1.

3. The method for preparing high-purity electrowinning nickel by chlorination leaching of nickel-containing sulfide materials according to claim 1, characterized in that: The amount of chlorine gas introduced is 1.0 to 2.0 times the theoretical amount of chlorine gas required for chlorination leaching; The chlorination leaching temperature is 60~110℃, and the chlorination leaching time is 1~5 h.

4. The method for preparing high-purity electrowinning nickel by chlorination leaching of nickel-containing sulfide materials according to claim 1, characterized in that: In the primary leachate, the concentration of nickel chloride (calculated as NiCl2) is 80~400 g / L, the concentration of Fe is 0.1~40 g / L, the concentration of Cu is 0.05~20 g / L, and the concentration of Co is 0.05~20 g / L.

5. The method for preparing high-purity electrowinning nickel by chlorination leaching of nickel-containing sulfide materials according to claim 1, characterized in that: The concentration of hydrochloric acid used in the secondary leaching is 3~8 mol / L; The liquid-solid mass ratio of the hydrochloric acid used in the secondary leaching to the primary leaching residue is 4~12:1; The temperature of the secondary leaching is 60~95℃, and the leaching time is 1~5 h.

6. The method for preparing high-purity electrowinning nickel by chlorination leaching of nickel-containing sulfide materials according to claim 1, characterized in that: The chloride ion regulator is selected from at least one of hydrochloric acid, sodium chloride, potassium chloride, and ammonium chloride; In the salting-out mixture, Cl - The calculated total chloride ion concentration in the liquid phase is 80~450 g / L.

7. The method for preparing high-purity electrowinning nickel by chlorination leaching of nickel-containing sulfide materials according to claim 1, characterized in that: The salting-out mixture is heated to 45-95°C and held for 10-60 min, then cooled to 10-35°C at a rate of 0.2-5.0°C / min for crystallization.

8. The method for preparing high-purity electrowinning nickel by chlorination leaching of nickel-containing sulfide materials according to claim 1, characterized in that: The nickel chloride crystals are washed with a washing solution. The washed nickel chloride crystals are dissolved with at least one of water, hydrochloric acid and the nickel chloride electrowinning solution obtained after electrowinning in step (5). The nickel ion concentration, nickel ion concentration and acidity are adjusted to obtain the nickel chloride pre-electrowinning solution. The washing solution is selected from at least one of saturated nickel chloride solution, hydrochloric acid solution and sodium chloride solution, and the liquid-solid mass ratio of the washing solution to nickel chloride crystals is 0.5~4.0∶1; The nickel ion concentration in the nickel chloride electrowinning solution is 60~260 g / L, the nickel ion concentration is 100~320 g / L, and the pH is 1.0~2.

8.

9. The method for preparing high-purity electrowinning nickel by chlorination leaching of nickel-containing sulfide materials according to claim 1, characterized in that: During the electrodeposition process, the electrodeposition temperature is controlled at 50~75℃, and the cathode current density is controlled at 220~340 A / m. 2 The cell voltage is 3.0~5.2V, and the electrowinning time is 8~60 h; During the electrowinning process, the anode is a titanium-based coated insoluble anode, and the cathode is a nickel starting electrode.

10. A method for preparing high-purity electrowinning nickel by chlorination leaching of nickel-containing sulfide materials according to any one of claims 1-9, characterized in that: The resulting electrolytic nickel meets the requirements for Ni9999 grade electrolytic nickel in GB / T 6516-2025, with a total nickel recovery rate of ≥99%.

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