Method for recovering valuable metals in ternary black powder

Abstract

The invention provides a method for recovering valuable metals in ternary black powder. The recovery method comprises the following steps: carrying out slurrying, acid leaching and impurity removal on ternary black powder to obtain an impurity-removed solution; performing manganese extraction on the impurity removal liquid to obtain a manganese-loaded organic phase and first raffinate; the first raffinate comprises cobalt, magnesium, nickel and lithium; performing cobalt extraction on the first raffinate to obtain a cobalt-loaded organic phase and second raffinate; pre-removing impurities from the second raffinate, and then performing nickel extraction on the second raffinate subjected to pre-impurity removal by adopting a DY319 organic phase to obtain a nickel-loaded organic phase and third raffinate; and carrying out magnesium precipitation reaction on the third raffinate, and carrying out solid-liquid separation to obtain a lithium-enriched solution. According to the method, the DY319 organic phase with high selectivity on nickel and lithium is adopted for nickel extraction, so that the nickel / lithium separation efficiency is improved, and the lithium recovery rate is increased; meanwhile, acid-base adjustment does not need to be repeatedly carried out in the nickel extraction step to compensate for insufficient nickel-lithium separation, and the cost and the environmental protection pressure are reduced.

Description

Technical Field

[0001] This invention belongs to the technical field of waste lithium-ion battery recycling methods, specifically relating to a method for recovering valuable metals from ternary lithium black powder. Background Technology

[0002] my country faces a relative scarcity of lithium resources, relying heavily on imports for its supply. In recent years, the persistently high price of imported lithium has significantly increased the manufacturing cost of ternary lithium-ion batteries. Simultaneously, the rapid development of the ternary lithium battery industry consumes substantial amounts of strategic metals such as nickel, cobalt, manganese, and copper, which cannot be met solely by domestic primary mineral resources. Retired ternary lithium batteries are often referred to as "urban mines," containing significantly higher levels of valuable metals like lithium, nickel, cobalt, and copper than natural ores. Therefore, developing efficient and environmentally friendly recycling technologies to achieve the recycling of valuable metal components is crucial for reducing my country's dependence on foreign sources for key mineral resources and ensuring the security of the new energy industry supply chain.

[0003] Currently, the industrial recovery of ternary lithium-ion battery black powder mainly employs hydrometallurgical processes. A typical process includes: discharging, crushing, and sorting the batteries to obtain ternary lithium-ion black powder; subsequently, acid leaching is performed using concentrated acid (such as concentrated sulfuric acid) in the presence of a reducing agent to transfer valuable metals into the solution; then, metal separation is achieved through multi-step extraction, commonly using P204 to remove manganese, P507 to extract cobalt, and C272 or P507 for nickel-magnesium co-extraction and separation; finally, lithium carbonate is obtained by precipitation from the lithium-containing solution. However, this traditional process has significant drawbacks: the key extractant P507 has a low separation coefficient for cobalt, magnesium, and lithium, while C272 also has a relatively low separation coefficient for magnesium, nickel, and lithium. This results in the entire extraction stage requiring large amounts of alkali and acid for pH adjustment and back-extraction, making the process lengthy and reagent costs high. More seriously, due to the low selectivity of the extractants for lithium, lithium is easily lost during extraction, ultimately leading to a decrease in lithium recovery rate.

[0004] Therefore, how to reduce the alkali and acid consumption in the extraction section while avoiding lithium loss and improving lithium recovery rate is a technical problem that urgently needs to be solved. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a method for recovering valuable metals from ternary black powder. This invention significantly improves nickel / lithium separation efficiency by employing a nickel extraction step using the DY319 organic phase, which exhibits high selectivity for both nickel and lithium. This fundamentally avoids lithium-ion entrainment losses caused by low separation coefficients in traditional processes, thereby increasing lithium recovery rates. This nickel extraction step eliminates the need for repeated acid-base adjustments to compensate for insufficient separation throughout the extraction stage, significantly reducing alkali and acid consumption. Furthermore, the process route is simple and orderly, efficiently recovering valuable metals such as nickel, cobalt, and manganese while ensuring efficient enrichment and recovery of lithium in subsequent stages. Overall, this improves the comprehensive resource recovery rate and reduces process operating costs and environmental impact.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] This invention provides a method for recovering valuable metals from ternary black powder, the recovery method comprising the following steps:

[0008] The ternary black powder is pulped, acid-leached, and impurity-removed to obtain a purification solution;

[0009] The impurity removal solution is subjected to manganese extraction to obtain a manganese-supported organic phase and a first raffinate; the first raffinate includes cobalt, magnesium, nickel and lithium;

[0010] The first raffinate was subjected to cobalt extraction to obtain a cobalt-supported organic phase and a second raffinate;

[0011] The second raffinate is pre-purified, and then nickel is extracted from the pre-purified second raffinate using a DY319 organic phase to obtain a nickel-supported organic phase and a third raffinate.

[0012] The third raffinate was subjected to a magnesium precipitation reaction, and after solid-liquid separation, a lithium-enriched solution was obtained.

[0013] This invention significantly improves nickel / lithium separation efficiency by employing a nickel extraction step using the DY319 organic phase, which exhibits high selectivity for both nickel and lithium. This fundamentally avoids lithium-ion entrainment losses caused by low separation coefficients in traditional processes, thereby increasing lithium recovery rates. This nickel extraction step eliminates the need for repeated acid-base adjustments to compensate for insufficient separation throughout the extraction process, significantly reducing alkali and acid consumption. Furthermore, the process route is simple and orderly, efficiently recovering valuable metals such as nickel, cobalt, and manganese while ensuring efficient enrichment and recovery of lithium in subsequent stages. Overall, this improves the comprehensive resource recovery rate and reduces process operating costs and environmental impact.

[0014] Preferably, during the pulping process, the mass ratio of ternary black powder to water is 1:(2-5), for example, it can be 1:2, 1:3, 1:4 or 1:5, etc.

[0015] Preferably, the acid leaching step includes: mixing the slurry of ternary black powder, acid solution and reducing agent, and carrying out a reduction leaching reaction.

[0016] Preferably, the impurity removal step includes: adjusting the pH of the ternary black powder leachate obtained after acid leaching to 4.8-5.3, and performing precipitation to remove impurities. For example, the pH may be 4.8, 4.9, 5, 5.1, 5.2, or 5.3, etc.

[0017] Preferably, the total concentration of nickel, cobalt and manganese in the impurity removal solution is 60-80 g / L, for example, it can be 60 g / L, 65 g / L, 70 g / L, 75 g / L or 80 g / L.

[0018] Preferably, the acid solution includes sulfuric acid.

[0019] Preferably, the concentration of the acid solution is 2-4 mol / L, for example, it can be 2 mol / L, 2.5 mol / L, 3.0 mol / L, 3.5 mol / L, or 4 mol / L.

[0020] Preferably, the reducing agent includes hydrogen peroxide and / or sodium metabisulfite.

[0021] Preferably, the temperature of the reduction leaching reaction is 70-80℃, for example, 70℃, 75℃ or 80℃, and the reaction time is 3-5h, for example, 3h, 4h or 5h.

[0022] Preferably, during the reduction leaching reaction, the pH of the solution system is 1-1.5, for example, it can be 1, 1.1, 1.2, 1.3, 1.4 or 1.5, etc.

[0023] Preferably, the manganese extractant used in the manganese extraction process includes P2O4.

[0024] Preferably, the manganese extraction method is multi-stage countercurrent extraction, with 8-9 extraction stages, for example, 8 or 9 stages.

[0025] Preferably, the concentrations of calcium, copper, zinc and manganese in the first raffinate are all less than 1.5 mg / L, for example, they can be 1.4 mg / L, 1.3 mg / L, 1.2 mg / L, 1.1 mg / L, 1 mg / L or 0.5 mg / L, etc.

[0026] Preferably, the cobalt extractant used in the cobalt extraction process includes P507.

[0027] Preferably, the cobalt extraction method is multi-stage countercurrent extraction, with 10-11 extraction stages, such as 10 or 11 stages.

[0028] Preferably, the concentration of cobalt in the second raffinate is less than 200 mg / L, for example, it can be 180 mg / L, 160 mg / L, 140 mg / L, 120 mg / L or 100 mg / L.

[0029] Preferably, before using DY319 organic phase to extract nickel from the second raffinate, the pH of the second raffinate is adjusted to 5-5.5, for example, it can be 5, 5.1, 5.2, 5.3, 5.4 or 5.5, etc.

[0030] In this invention, before using the DY319 organic phase to extract nickel from the second raffinate, the pH of the second raffinate is adjusted to a suitable range. The purpose is to optimize the selective extraction environment of nickel by the DY319 organic phase: on the one hand, it improves the complexation reaction efficiency between nickel ions and DY319, significantly increasing the nickel extraction rate; on the other hand, it inhibits the co-extraction of metal ions such as magnesium and lithium in the second raffinate, reducing the difficulty of subsequent purification of the nickel-loaded organic phase, and finally obtaining a high-purity nickel product, ensuring the efficient recovery and quality of nickel resources.

[0031] Preferably, the DY319 organic phase includes a DY319 extractant and a diluent.

[0032] Preferably, the diluent comprises sulfonated kerosene and / or butyl acetate.

[0033] Preferably, the volume concentration of DY319 in the DY319 organic phase is 30-45%, for example, it can be 30%, 35%, 40% or 45%, etc.

[0034] In this invention, a suitable volume concentration of DY319 is beneficial to improving the loading capacity and extraction rate of nickel ions in the organic phase, ensuring efficient enrichment of nickel; enhancing the selectivity for separating nickel and lithium, reducing co-extraction of impurities; avoiding the increase in viscosity of the organic phase and difficulty in phase separation due to excessively high concentration, or the incomplete extraction caused by excessively low concentration, thus ensuring the stability and economy of the nickel extraction process, and finally obtaining a high-purity nickel-loaded organic phase.

[0035] Preferably, the DY319 organic phase also includes a co-extractant.

[0036] Preferably, in the DY319 organic phase, the mass ratio of DY319 extractant to co-extractant is (8-12):1, for example, it can be 8:1, 9:1, 10:1, 11:1 or 12:1, etc.

[0037] Preferably, the co-extractant comprises any one or a combination of at least two of tributyl phosphate, 2-octanol, or 2-ethylhexanol.

[0038] This invention employs the aforementioned co-extractants in combination with DY319 extractant at a specific mass ratio. This significantly improves the complexation stability of nickel ions with the extraction system, enhances the separation coefficient of nickel and lithium, and further suppresses the co-extraction of impurity ions. Simultaneously, it optimizes the flowability and phase separation efficiency of the organic phase, reduces extractant emulsification, and lowers reagent consumption during the extraction process. Furthermore, it broadens the operating pH window for nickel extraction, improves the process's adaptability to fluctuations in the composition of the feed solution, and ultimately achieves efficient enrichment and high-purity recovery of nickel, ensuring the accuracy and economy of subsequent valuable metal separation.

[0039] Preferably, during the nickel extraction process, the volume ratio of the DY319 organic phase to the second raffinate is (1-10):(10-1), wherein the selection range of the DY319 organic phase "1-10" can be, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, and the selection range of the second raffinate "10-1" can be, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10.

[0040] Preferably, the nickel extraction is carried out using a multi-stage countercurrent extraction method, with 11-13 extraction stages, such as 11, 12, or 13 stages.

[0041] Preferably, during the nickel extraction process, the temperature of the solution system is 25-40°C, for example, 25°C, 30°C, 35°C or 40°C, and the mixing and stirring time is 5-8 minutes, for example, 5 minutes, 6 minutes, 7 minutes or 8 minutes.

[0042] Preferably, in the nickel-supported organic phase, the lithium concentration is less than 1.5 mg / L, for example, it can be 1 mg / L, 0.8 mg / L or 0.5 mg / L, etc.

[0043] Preferably, the concentration of nickel in the third raffinate is less than 1 mg / L, for example, it can be 1 mg / L, 0.8 mg / L or 0.5 mg / L.

[0044] Preferably, the recycling method includes the following steps:

[0045] (1) Provide ternary black powder;

[0046] The ternary black powder and water are mixed at a mass ratio of 1:(2-5) to obtain a slurry of ternary black powder.

[0047] Under stirring conditions, the slurry of the ternary black powder, acid solution, and reducing agent are mixed and subjected to a reduction leaching reaction at 70-80℃ for 3-5 hours to obtain a ternary black powder leaching slurry; the acid solution includes sulfuric acid; the reducing agent includes hydrogen peroxide and / or sodium metabisulfite; during the reduction leaching reaction, the pH of the solution system is 1-1.5.

[0048] A calcium hydroxide aqueous slurry with a solidification content of 20-25% (e.g., 20%, 21%, 22%, 23%, 24%, or 25%) is added dropwise at a uniform rate to the ternary black powder leachate slurry. The pH is adjusted to 4.8-5.2, and the stirring speed is controlled at 200-400 rpm (e.g., 200 rpm, 300 rpm, or 400 rpm) and the temperature is controlled at 60-65℃ (e.g., 60℃, 61℃, 62℃, or 63℃). The mixture is subjected to precipitation at ℃, 64℃, or 65℃, etc., for 0.5-1.5h (e.g., 0.5h, 1h, or 1.5h, etc.). After solid-liquid separation, a purified liquid and a filter residue are obtained. In the purified liquid, the total concentration of nickel, cobalt, and manganese is 60-80g / L, and the concentration of iron and aluminum is ≤0.1mg / L (e.g., 0.1mg / L, 0.05mg / L, or 0.01mg / L, etc.). The filter residue includes graphite, iron-aluminum hydroxide, and calcium salt.

[0049] (2) Control the pH of the impurity removal solution to 4.9-5.3 (e.g., 4.9, 5, 5.1, 5.2 or 5.3, etc.), and then use a manganese extractant to extract the impurity removal solution to obtain a manganese extract and a first raffinate; the first raffinate includes cobalt, magnesium, nickel and lithium; the concentrations of calcium, copper, zinc and manganese in the first raffinate are all less than 1.5 mg / L; the extraction method of the manganese extraction is multi-stage countercurrent extraction, with 8-9 extraction stages; the manganese extractant includes P2O4.

[0050] (3) The manganese-supported organic phase is back-extracted with hydrochloric acid to obtain waste copper-manganese liquid; after removing copper and zinc from the waste copper-manganese liquid with sodium sulfide, it is extracted and back-extracted with C272 extractant to obtain battery-grade manganese sulfate product.

[0051] The pH of the first raffinate is controlled to 3.7-4.1 (e.g., 3.7, 3.8, 3.9, 4, or 4.1, etc.), and then cobalt extraction is performed on the first raffinate using a cobalt extractant to obtain a cobalt-supported organic phase and a second raffinate; the second raffinate includes magnesium, nickel, and lithium; the concentration of cobalt in the second raffinate is less than 200 mg / L; the cobalt extraction method is multi-stage countercurrent extraction with 10-11 extraction stages; the cobalt extractant includes P507.

[0052] (4) The cobalt extract is back-extracted using a sulfuric acid solution with a concentration of 5-6N (e.g., 5N, 5.5N, or 6N, etc. It should be noted that the unit "N" is the equivalent concentration, which characterizes the number of gram equivalents of solute in a unit volume of solution. For sulfuric acid solution, the conversion formula between its equivalent concentration N and molar concentration c is c=2N, which is the hydrogen ion concentration when completely dissociated; for example, 5N sulfuric acid corresponds to a sulfuric acid molar concentration of 2.5 mol / L and a hydrogen ion concentration of 5 mol / L. The same applies below) to obtain a back-extract. Then, the back-extract is purified using P204 extractant to obtain battery-grade cobalt sulfate product.

[0053] The second raffinate is treated with a resin (exemplarily, such as HP3500 resin) to remove phosphorus and fluoride. The pH of the second raffinate is then adjusted to 5-5.5. Next, nickel is extracted from the second raffinate using a DY319 organic phase, yielding a nickel-loaded organic phase and a third raffinate. The DY319 organic phase includes a DY319 extractant and a diluent, the diluent comprising sulfonated kerosene and / or butyl acetate. The volume concentration of DY319 in the DY319 organic phase is... The concentration of nickel in the solution is 30-45%; during the nickel extraction process, the volume ratio of the DY319 organic phase to the second raffinate is (1-10):(10-1); the nickel extraction is carried out using a multi-stage countercurrent extraction method, with 11-13 extraction stages; during the nickel extraction process, the temperature of the solution system is 20-25℃, and the mixing and stirring time is 5-8 min; the concentration of nickel in the third raffinate is less than 1 mg / L; the concentration of lithium in the nickel-supported organic phase is less than 1.5 mg / L.

[0054] (5) The nickel-supported organic phase is back-extracted using a sulfuric acid solution with a concentration of 5-6N (e.g., 5N, 5.5N, or 6N) to obtain a back-extract. The back-extract is then purified using P204 extractant to obtain battery-grade nickel sulfate product.

[0055] Under stirring conditions, a precipitant is added to the third raffinate to adjust the pH to 11.0-11.5 (e.g., 11, 11.1, 11.2, or 11.5, etc.), and the reaction temperature is 40-50℃ (e.g., 40℃, 45℃, or 50℃, etc.) to carry out a magnesium precipitation reaction. After solid-liquid separation, a lithium-enriched solution with a magnesium concentration ≤0.05mg / L (e.g., 0.05mg / L, 0.03mg / L, or 0.01mg / L, etc.) is obtained. Then, a precipitant is added to the lithium-enriched solution to carry out a lithium precipitation reaction at a reaction temperature of 90-95℃ (e.g., 90℃, 92℃, or 95℃, etc.). After aging, filtration, washing, and drying, the lithium product is obtained.

[0056] For example, when performing a magnesium precipitation reaction, the precipitant used may be sodium hydroxide, sodium carbonate, or calcium hydroxide. When performing a lithium precipitation reaction, the precipitant used may be sodium carbonate, sodium bicarbonate, or disodium hydrogen phosphate.

[0057] In this invention, the calcium hydroxide slurry is added at a uniform rate to prevent the loss of valuable metals such as nickel and cobalt due to a sudden increase in local pH, thereby improving the repeatability of the process.

[0058] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0059] Compared with the prior art, the present invention has the following beneficial effects:

[0060] This invention significantly improves nickel / lithium separation efficiency by employing a nickel extraction step using the DY319 organic phase, which exhibits high selectivity for both nickel and lithium. This fundamentally avoids lithium-ion entrainment losses caused by low separation coefficients in traditional processes, thereby increasing lithium recovery rates. This nickel extraction step eliminates the need for repeated acid-base adjustments to compensate for insufficient separation throughout the extraction process, significantly reducing alkali and acid consumption. Furthermore, the process route is simple and orderly, efficiently recovering valuable metals such as nickel, cobalt, and manganese while ensuring efficient enrichment and recovery of lithium in subsequent stages. Overall, this improves the comprehensive resource recovery rate and reduces process operating costs and environmental impact. Attached Figure Description

[0061] Figure 1 This is a process flow diagram of the recycling method provided in Embodiment 1 of the present invention. Detailed Implementation

[0062] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0063] It should be noted that the main components of the ternary black powder used below are shown in Table 1:

[0064] Table 1

[0065]

[0066] Example 1

[0067] This embodiment provides a method for recovering valuable metals from ternary black powder, and its process flow diagram is as follows: Figure 1 As shown, the recycling method includes the following steps:

[0068] (1) Mix ternary black powder and water at a mass ratio of 1:3.5 to obtain ternary black powder slurry.

[0069] Under stirring conditions, the slurry of the ternary black powder, acid solution, and reducing agent are mixed and subjected to a reduction leaching reaction at 75°C for 4 hours to obtain a ternary black powder leaching slurry; the acid solution is sulfuric acid with a concentration of 2 mol / L; the reducing agent is hydrogen peroxide, and the amount added is 8% of the mass of the ternary black powder; during the reduction leaching reaction, the pH of the solution system is 1.3.

[0070] A calcium hydroxide aqueous slurry with a solid content of 23% was added dropwise at a uniform rate to the ternary black powder leaching slurry. The pH was adjusted to 5, the stirring speed was controlled at 300 rpm, and the temperature was controlled at 63°C. The sedimentation and impurity removal were carried out for 1 hour. After solid-liquid separation, impurity-removed liquid and filter residue were obtained. In the impurity-removed liquid, the total concentration of nickel, cobalt and manganese was 70 g / L, and the concentration of iron and aluminum was ≤0.1 mg / L. The filter residue included graphite, iron-aluminum hydroxide and calcium salt.

[0071] (2) Control the pH of the impurity removal solution to 5.1, and then use a manganese extractant to extract the impurity removal solution with manganese to obtain a manganese extract and a first raffinate; the first raffinate contains cobalt, magnesium, nickel and lithium; the concentrations of calcium, copper, zinc and manganese in the first raffinate are all less than 1.5 mg / L; the extraction method of the manganese extraction is multi-stage countercurrent extraction, with 8 extraction stages; the manganese extractant is P204 (volume concentration 25%, diluent is sulfonated kerosene).

[0072] (3) The manganese-supported organic phase was back-extracted with 2 mol / L hydrochloric acid to obtain waste copper-manganese liquid; after removing copper and zinc from the waste copper-manganese liquid with sodium sulfide, it was extracted and back-extracted with C272 extractant to obtain battery-grade manganese sulfate product.

[0073] The pH of the first raffinate is controlled to 3.9, and then cobalt extraction is performed on the first raffinate using a cobalt extractant to obtain a cobalt-loaded organic phase and a second raffinate; the second raffinate includes magnesium, nickel and lithium; the concentration of cobalt in the second raffinate is less than 190 mg / L; the cobalt extraction method is multi-stage countercurrent extraction with 10 extraction stages; the cobalt extractant is P507 (volume concentration 25%, diluent is sulfonated kerosene).

[0074] (4) The cobalt extract was back-extracted with a sulfuric acid solution of 5.5N to obtain a back-extracted solution, and then the back-extracted solution was purified with P204 extractant to obtain battery-grade cobalt sulfate product.

[0075] The second raffinate was treated with HP3500 resin to remove phosphorus and fluoride.

[0076] The pH of the second raffinate after phosphorus and fluoride removal was adjusted to 5, and then nickel extraction was performed on the second raffinate using a DY319 organic phase to obtain a nickel-loaded organic phase and a third raffinate. The DY319 organic phase included DY319 extractant and butyl acetate. The volume concentration of DY319 in the DY319 organic phase was 35%. During the nickel extraction, the volume ratio of the DY319 organic phase to the second raffinate was 5:5. The nickel extraction was carried out using a multi-stage countercurrent extraction method with 11 extraction stages. During the nickel extraction, the temperature of the solution system was 25°C, and the mixing time was 7 min. The concentration of nickel in the third raffinate was less than 1 mg / L. The concentration of lithium in the nickel-loaded organic phase was less than 1.3 mg / L.

[0077] (5) The nickel-supported organic phase is back-extracted with a sulfuric acid solution of concentration of 5.5N to obtain a back-extracting solution, and then the back-extracting solution is purified with P204 extractant to obtain battery-grade nickel sulfate product.

[0078] Sodium hydroxide was added to the third raffinate under stirring conditions to adjust the pH to 11.2. The reaction temperature was 45°C, and a magnesium precipitation reaction was carried out for 30 minutes. After solid-liquid separation, a lithium enrichment solution with a magnesium concentration ≤0.05 mg / L was obtained. Then, sodium carbonate was added to the lithium enrichment solution to carry out a lithium precipitation reaction at a reaction temperature of 92°C. After aging for 2 hours, the lithium carbonate product was obtained after filtration, washing, and drying.

[0079] Example 2

[0080] This embodiment provides a method for recovering valuable metals from ternary black powder, the recovery method comprising the following steps:

[0081] (1) Mix ternary black powder and water at a mass ratio of 1:2 to obtain ternary black powder slurry.

[0082] Under stirring conditions, the slurry of the ternary black powder, acid solution, and reducing agent are mixed and subjected to a reduction leaching reaction at 70°C for 5 hours to obtain a ternary black powder leaching slurry; the acid solution is sulfuric acid with a concentration of 3 mol / L; the reducing agent is hydrogen peroxide, and the amount added is 8% of the mass of the ternary black powder; during the reduction leaching reaction, the pH of the solution system is 1.

[0083] A calcium hydroxide slurry with a solid content of 20% was added dropwise to the ternary black powder leaching slurry at a uniform rate. The pH was adjusted to 4.8, and the stirring speed was controlled at 200 rpm and the temperature at 65°C. The mixture was allowed to settle and remove impurities for 0.5 hours. After solid-liquid separation, a purified liquid and a filter residue were obtained. The total concentration of nickel, cobalt, and manganese in the purified liquid was 60 g / L, and the concentration of iron and aluminum was ≤0.1 mg / L. The filter residue contained graphite, iron-aluminum hydroxide, and calcium salts.

[0084] (2) Control the pH of the impurity removal solution to 4.9, and then use a manganese extractant to extract the impurity removal solution with manganese to obtain a manganese extract and a first raffinate; the first raffinate contains cobalt, magnesium, nickel and lithium; the concentrations of calcium, copper, zinc and manganese in the first raffinate are all less than 1.5 mg / L; the extraction method of the manganese extraction is multi-stage countercurrent extraction, with 8 extraction stages; the manganese extractant is P204 (volume concentration 25%, diluent is sulfonated kerosene).

[0085] (3) The manganese-supported organic phase was back-extracted with 2 mol / L hydrochloric acid to obtain waste copper-manganese liquid; after removing copper and zinc from the waste copper-manganese liquid with sodium sulfide, it was extracted and back-extracted with C272 extractant to obtain battery-grade manganese sulfate product.

[0086] The pH of the first raffinate is controlled to 3.7, and then cobalt extraction is performed on the first raffinate using a cobalt extractant to obtain a cobalt-loaded organic phase and a second raffinate; the second raffinate includes magnesium, nickel and lithium; the concentration of cobalt in the second raffinate is less than 195 mg / L; the cobalt extraction method is multi-stage countercurrent extraction with 10 extraction stages; the cobalt extractant is P507 (volume concentration 25%, diluent is sulfonated kerosene).

[0087] (4) The cobalt extract is back-extracted with a sulfuric acid solution of concentration 5N to obtain a back-extracted solution, and then the back-extracted solution is purified with P204 extractant to obtain battery-grade cobalt sulfate product.

[0088] The second raffinate was treated with HP3500 resin to remove phosphorus and fluoride.

[0089] The pH of the second raffinate after phosphorus and fluoride removal was adjusted to 5.1. Then, nickel extraction was performed on the second raffinate using a DY319 organic phase to obtain a nickel-loaded organic phase and a third raffinate. The DY319 organic phase included DY319 extractant and butyl acetate. The volume concentration of DY319 in the DY319 organic phase was 30%. During the nickel extraction, the volume ratio of the DY319 organic phase to the second raffinate was 5:5. The nickel extraction was performed using a multi-stage countercurrent extraction method with 11 extraction stages. During the nickel extraction, the solution temperature was 30°C, and the mixing time was 6 minutes. The nickel concentration in the third raffinate was less than 1.2 mg / L. The lithium concentration in the nickel-loaded organic phase was less than 1.5 mg / L.

[0090] (5) The nickel-supported organic phase is back-extracted using a sulfuric acid solution with a concentration of 5N to obtain a back-extracting solution. Then, the back-extracting solution is purified using P204 extractant to obtain battery-grade nickel sulfate product.

[0091] Sodium hydroxide was added to the third raffinate under stirring conditions to adjust the pH to 11. The reaction temperature was 40°C, and a magnesium precipitation reaction was carried out for 30 minutes. After solid-liquid separation, a lithium enrichment solution with a magnesium concentration ≤0.05 mg / L was obtained. Then, sodium carbonate was added to the lithium enrichment solution to carry out a lithium precipitation reaction at a reaction temperature of 90°C. After aging for 2 hours, the lithium carbonate product was obtained after filtration, washing, and drying.

[0092] Example 3

[0093] This embodiment provides a method for recovering valuable metals from ternary black powder, the recovery method comprising the following steps:

[0094] (1) Mix ternary black powder and water at a mass ratio of 1:5 to obtain ternary black powder slurry.

[0095] Under stirring conditions, the slurry of the ternary black powder, acid solution, and reducing agent are mixed and subjected to a reduction leaching reaction at 80°C for 3 hours to obtain a ternary black powder leaching slurry; the acid solution is sulfuric acid with a concentration of 4 mol / L; the reducing agent is hydrogen peroxide, and the amount added is 8% of the mass of the ternary black powder; during the reduction leaching reaction, the pH of the solution system is 1.5.

[0096] A calcium hydroxide slurry with a solid content of 25% was added dropwise to the ternary black powder leaching slurry at a uniform rate. The pH was adjusted to 5.2, and the stirring speed was controlled at 400 rpm and the temperature at 60°C. The mixture was allowed to settle and remove impurities for 1.5 hours. After solid-liquid separation, a purified liquid and a filter residue were obtained. The total concentration of nickel, cobalt, and manganese in the purified liquid was 80 g / L, and the concentration of iron and aluminum was ≤0.1 mg / L. The filter residue contained graphite, iron-aluminum hydroxide, and calcium salts.

[0097] (2) Control the pH of the impurity removal solution to 5.3, and then use a manganese extractant to extract the impurity removal solution with manganese to obtain a manganese extract and a first raffinate; the first raffinate contains cobalt, magnesium, nickel and lithium; the concentrations of calcium, copper, zinc and manganese in the first raffinate are all less than 1.5 mg / L; the extraction method of the manganese extraction is multi-stage countercurrent extraction, with 8 extraction stages; the manganese extractant is P204 (volume concentration 25%, diluent is sulfonated kerosene).

[0098] (3) The manganese-supported organic phase was back-extracted with 2 mol / L hydrochloric acid to obtain waste copper-manganese liquid; after removing copper and zinc from the waste copper-manganese liquid with sodium sulfide, it was extracted and back-extracted with C272 extractant to obtain battery-grade manganese sulfate product.

[0099] The pH of the first raffinate is controlled to 4.1, and then cobalt extraction is performed on the first raffinate using a cobalt extractant to obtain a cobalt-loaded organic phase and a second raffinate; the second raffinate includes magnesium, nickel and lithium; the concentration of cobalt in the second raffinate is less than 180 mg / L; the cobalt extraction method is multi-stage countercurrent extraction with 10 extraction stages; the cobalt extractant is P507 (volume concentration 25%, diluent is sulfonated kerosene).

[0100] (4) The cobalt extract was back-extracted with a sulfuric acid solution of concentration 6N to obtain a back-extracted solution, and then the back-extracted solution was purified with P204 extractant to obtain battery-grade cobalt sulfate product.

[0101] The second raffinate was treated with HP3500 resin to remove phosphorus and fluoride.

[0102] The pH of the second raffinate after phosphorus and fluoride removal was adjusted to 5.2. Then, nickel extraction was performed on the second raffinate using a DY319 organic phase to obtain a nickel-loaded organic phase and a third raffinate. The DY319 organic phase included DY319 extractant and butyl acetate. The volume concentration of DY319 in the DY319 organic phase was 40%. During the nickel extraction, the volume ratio of the DY319 organic phase to the second raffinate was 5:5. The nickel extraction was performed using a multi-stage countercurrent extraction method with 12 extraction stages. During the nickel extraction, the solution temperature was 40°C, and the mixing time was 8 minutes. The nickel concentration in the third raffinate was less than 0.8 mg / L. The lithium concentration in the nickel-loaded organic phase was less than 1 mg / L.

[0103] (5) The nickel-supported organic phase is back-extracted using a sulfuric acid solution with a concentration of 6N to obtain a back-extracting solution. Then, the back-extracting solution is purified using P204 extractant to obtain battery-grade nickel sulfate product.

[0104] Sodium hydroxide was added to the third raffinate under stirring conditions to adjust the pH to 11.5. The reaction temperature was 55°C, and a magnesium precipitation reaction was carried out for 30 minutes. After solid-liquid separation, a lithium enrichment solution with a magnesium concentration ≤0.05 mg / L was obtained. Then, sodium carbonate was added to the lithium enrichment solution to carry out a lithium precipitation reaction at a reaction temperature of 95°C. After aging for 2 hours, the lithium carbonate product was obtained after filtration, washing, and drying.

[0105] Example 4

[0106] The difference between this embodiment and embodiment 1 is that, in step (4), the DY319 organic phase also includes a co-extractant, which is tributyl phosphate, and the mass ratio of DY319 extractant to tributyl phosphate is 10:1.

[0107] The remaining preparation methods and parameters are consistent with those in Example 1.

[0108] Example 5

[0109] The difference between this embodiment and embodiment 1 is that in step (4), the pH of the second raffinate is not adjusted, but nickel extraction is performed directly on the second raffinate (pH 4.8) after phosphorus and fluorine removal using the DY319 organic phase.

[0110] The remaining preparation methods and parameters are consistent with those in Example 1.

[0111] Example 6

[0112] The difference between this embodiment and embodiment 1 is that the volume concentration of DY319 in the organic phase of DY319 in step (4) is 15%.

[0113] The remaining preparation methods and parameters are consistent with those in Example 1.

[0114] Example 7

[0115] The difference between this embodiment and embodiment 1 is that the volume concentration of DY319 in the organic phase of DY319 in step (4) is 60%.

[0116] The remaining preparation methods and parameters are consistent with those in Example 1.

[0117] Example 8

[0118] The difference between this embodiment and embodiment 1 is that the nickel extraction in step (4) is carried out by single-stage countercurrent extraction.

[0119] The remaining preparation methods and parameters are consistent with those in Example 1.

[0120] Example 9

[0121] The difference between this embodiment and embodiment 1 is that the temperature of the solution system is 15°C during the nickel extraction process in step (4).

[0122] The remaining preparation methods and parameters are consistent with those in Example 1.

[0123] Example 10

[0124] The difference between this embodiment and embodiment 1 is that the temperature of the solution system is 65°C during the nickel extraction process described in step (4).

[0125] The remaining preparation methods and parameters are consistent with those in Example 1.

[0126] Comparative Example 1

[0127] The difference between this comparative example and Example 1 is that in step (4), the DY319 organic phase is replaced with P507 extractant.

[0128] The remaining preparation methods and parameters are consistent with those in Example 1.

[0129] Comparative Example 2

[0130] The difference between this comparative example and Example 1 is that in step (4), the DY319 organic phase is replaced with C272 extractant.

[0131] The remaining preparation methods and parameters are consistent with those in Example 1.

[0132] Performance testing

[0133] The purity of the battery-grade nickel sulfate and lithium carbonate products obtained in the above examples and comparative examples was tested using inductively coupled plasma optical emission spectrometry (ICP-OES), and the lithium recovery rate was calculated.

[0134] The results are shown in Table 2.

[0135] Table 2

[0136]

[0137] analyze:

[0138] As shown in Table 2, this invention significantly improves the nickel / lithium separation efficiency by employing the DY319 organic phase, which has high selectivity for both nickel and lithium, for the nickel extraction step. This fundamentally avoids lithium ion entrainment losses caused by low separation coefficients in traditional processes, thereby increasing lithium recovery rates. This nickel extraction step eliminates the need for repeated acid-base adjustments to compensate for insufficient separation throughout the extraction process, significantly reducing alkali and acid consumption. Furthermore, the process route is simple and orderly, efficiently recovering valuable metals such as nickel, cobalt, and manganese while ensuring efficient enrichment and recovery of lithium in subsequent stages. Overall, this improves the comprehensive resource recovery rate and reduces process operating costs and environmental pressure.

[0139] As can be seen from the comparison between Example 1 and Example 5, if the pH of the second raffinate is not adjusted, and nickel extraction is performed directly using the DY319 organic phase after obtaining the second raffinate in step (3), the complexation reaction efficiency of the DY319 extractant with nickel ions will decrease significantly, and the nickel extraction rate will decrease significantly. At the same time, the co-extraction behavior of impurities such as magnesium ions cannot be suppressed, resulting in the impurity content in the nickel-loaded organic phase exceeding the standard and the purity being difficult to meet the standard. Furthermore, the nickel ions that are not effectively extracted and the co-extracted impurities will remain in the subsequent lithium enrichment process, competing with lithium ions for reaction sites or forming co-precipitates, resulting in a significant decrease in the purity of lithium carbonate products, a significant decline in the lithium recovery rate, a waste of lithium resources, and a weakening of the economic benefits of the entire recovery process.

[0140] A comparison of Examples 1 and 6-7 shows that if the volume concentration of DY319 in the organic phase is too low, the residual magnesium and lithium impurities in the nickel-loaded organic phase will exceed the standard, reducing the purity of the battery-grade nickel sulfate product. Furthermore, unextracted nickel ions and residual magnesium ions will enter the subsequent lithium extraction process, forming co-precipitates or impurity phases with lithium ions, leading to a decrease in the purity of the lithium carbonate product and a reduction in lithium recovery rate. If the volume concentration of DY319 in the organic phase is too high, the viscosity of the organic phase will increase, and the fluidity will deteriorate, making oil-water phase separation difficult and prone to emulsification. The co-extraction phenomenon of impurities such as magnesium ions will intensify, affecting the purity of the nickel sulfate product. Moreover, the impurities will enter the lithium extraction process, resulting in a decrease in the purity of the lithium carbonate product and a reduction in recovery rate.

[0141] A comparison of Examples 1 and 8 shows that if nickel extraction is carried out using a single-stage countercurrent extraction method, the separation efficiency is limited and the purity of nickel sulfate is difficult to meet battery-grade requirements; magnesium-nickel co-precipitation occurs during lithium carbonate precipitation, resulting in excessive impurity content, and magnesium-nickel impurities affect the precipitation reaction of lithium ions, thus reducing the lithium recovery rate.

[0142] A comparison of Examples 1 and 9-10 shows that if the temperature of the solution system is too low during nickel extraction, the kinetic rate of the extraction reaction will be significantly slowed down, and the mass transfer process between the organic phase and the aqueous phase will be insufficient, resulting in the DY319 extractant failing to fully complex with nickel ions. Simultaneously, low temperature will slightly increase the viscosity of the organic phase, slow down the phase separation rate, and easily produce a small amount of entrainment, thus increasing the amount of magnesium and lithium co-extracted, reducing the purity of battery-grade nickel sulfate and lithium carbonate products, and lowering the recovery rate. Conversely, if the temperature of the solution system is too high during nickel extraction, the equilibrium of the complexation reaction between nickel and DY319 will shift in the reverse direction, simultaneously reducing the separation coefficient between nickel and magnesium and lithium, and significantly exacerbating the co-extraction of impurities. Furthermore, high temperature will decrease the viscosity of the organic phase but cause more vigorous molecular motion, easily leading to emulsification and entrainment problems, increasing the volatility and loss of the extractant, further affecting the separation effect of nickel and impurities, and resulting in a decrease in the purity of the nickel sulfate product. Furthermore, residual organic impurities from emulsification and co-extracted metallic impurities will enter the subsequent lithium enrichment process, competing with lithium ions for precipitant and forming co-precipitates, resulting in excessive impurity content and decreased purity in lithium carbonate products. High temperatures will also affect the kinetic balance of the lithium precipitation reaction, potentially causing reaction imbalance and preventing lithium ions from being fully converted into lithium carbonate. Combined with the interference of impurities, this ultimately leads to a significant decrease in lithium recovery rate.

[0143] A comparison of Example 1 and Comparative Examples 1-2 shows that if the DY319 organic phase is replaced with P507 extractant, the co-extraction of magnesium and lithium impurities during nickel extraction increases significantly due to the small separation coefficient of P507 for cobalt, magnesium, and lithium. This leads to excessive impurities in the nickel-loaded organic phase, preventing the nickel sulfate product from reaching battery-grade purity. Furthermore, P507's poor separation effect on magnesium and lithium causes residual magnesium impurities to enter the lithium extraction process and co-precipitate with lithium carbonate, resulting in decreased product purity and reduced recovery rate. If the DY319 organic phase is replaced... Using P507 as the extractant, C272 has a low separation coefficient for magnesium, nickel, and lithium, making it unable to effectively distinguish the three. A large amount of magnesium and lithium impurities remain in the nickel-loaded organic phase, which is difficult to remove subsequently, resulting in nickel sulfate products with purity lower than battery-grade standards. Furthermore, the unseparated magnesium and nickel impurities enter the lithium extraction process, forming impurity-containing lithium carbonate precipitates, leading to a decrease in the purity of lithium carbonate products. Simultaneously, C272 strongly interferes with lithium separation, and the co-precipitation of magnesium, nickel, and lithium is severe, making it difficult to efficiently enrich and recover lithium ions, resulting in a waste of lithium resources.

[0144] It should be noted that the present invention is illustrated through the above embodiments, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, additions of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for recovering valuable metals from ternary black powder, characterized in that, The recycling method includes the following steps: The ternary black powder is pulped, acid-leached, and impurity-removed to obtain a purification solution; The impurity removal solution is subjected to manganese extraction to obtain a manganese-supported organic phase and a first raffinate; the first raffinate includes cobalt, magnesium, nickel and lithium; The first raffinate was subjected to cobalt extraction to obtain a cobalt-supported organic phase and a second raffinate; The second raffinate was pre-purified, and then nickel was extracted from the pre-purified second raffinate using a DY319 organic phase to obtain a nickel-supported organic phase and a third raffinate. The third raffinate was subjected to a magnesium precipitation reaction, and after solid-liquid separation, a lithium-enriched solution was obtained.

2. The recycling method according to claim 1, characterized in that, During the pulping process, the mass ratio of ternary black powder to water is 1:(2-5); And / or, the acid leaching step includes: mixing the slurry of ternary black powder, acid solution and reducing agent, and carrying out a reduction leaching reaction; And / or, the impurity removal step includes: adjusting the pH of the ternary black powder leachate obtained after acid leaching to 4.8-5.2, and performing precipitation to remove impurities; And / or, the total concentration of nickel, cobalt and manganese in the impurity removal solution is 60-80 g / L.

3. The recycling method according to claim 2, characterized in that, The acid solution includes sulfuric acid; And / or, the reducing agent includes hydrogen peroxide and / or sodium metabisulfite; And / or, the temperature of the reduction leaching reaction is 70-80℃, and the reaction time is 3-5h; And / or, during the reduction leaching reaction, the pH of the solution system is 1-1.

5.

4. The recycling method according to any one of claims 1-3, characterized in that, In the process of manganese extraction, the manganese extractant used includes P2O4; And / or, the extraction method for manganese extraction is multi-stage countercurrent extraction, with 8-9 extraction stages; And / or, in the first raffinate, the concentrations of calcium, copper, zinc and manganese are all less than 1.5 mg / L.

5. The recycling method according to any one of claims 1-4, characterized in that, In the cobalt extraction process, the cobalt extractant used includes P507; And / or, the cobalt extraction method is multi-stage countercurrent extraction, with 10-11 extraction stages; And / or, in the second raffinate, the concentration of cobalt is less than 200 mg / L.

6. The recycling method according to any one of claims 1-5, characterized in that, Before using DY319 organic solvent to extract nickel from the second raffinate, the pH of the second raffinate is adjusted to 5-5.

5.

7. The recycling method according to any one of claims 1-6, characterized in that, The DY319 organic phase includes a DY319 extractant and a diluent; The diluent includes sulfonated kerosene and / or butyl acetate; And / or, in the DY319 organic phase, the volume concentration of DY319 is 30-45%.

8. The recycling method according to claim 7, characterized in that, The organic phase of DY319 also includes a co-extractant; In the DY319 organic phase, the mass ratio of DY319 extractant to co-extractant is (8-12):1; The co-extractant includes any one or a combination of at least two of the following: tributyl phosphate, 2-octanol, or 2-ethylhexanol.

9. The recycling method according to any one of claims 1-8, characterized in that, During the nickel extraction process, the volume ratio of the DY319 organic phase to the second raffinate is (1-10):(10-1); And / or, the nickel extraction is carried out using a multi-stage countercurrent extraction method, with 11-13 extraction stages; And / or, during the nickel extraction process, the temperature of the solution system is 25-40℃, and the mixing and stirring time is 5-8 min; And / or, in the nickel-supported organic phase, the lithium concentration is less than 1.5 mg / L; And / or, in the third raffinate, the concentration of nickel is less than 1 mg / L.

10. The recycling method according to any one of claims 1-9, characterized in that, The recycling method includes the following steps: (1) Provide ternary black powder; The ternary black powder and water are mixed at a mass ratio of 1:(2-5) to obtain a slurry of ternary black powder; Under stirring conditions, the slurry of the ternary black powder, acid solution, and reducing agent are mixed and subjected to a reduction leaching reaction at 70-80℃ for 3-5 hours to obtain a ternary black powder leaching slurry; the acid solution includes sulfuric acid; the reducing agent includes hydrogen peroxide and / or sodium metabisulfite; during the reduction leaching reaction, the pH of the solution system is 1-1.5; A calcium hydroxide aqueous slurry with a solid content of 20-25% is added dropwise to the ternary black powder leaching slurry at a uniform rate. The pH is adjusted to 4.8-5.2, and the stirring speed is controlled at 200-400 rpm and the temperature at 60-65℃. Precipitation and impurity removal are carried out for 0.5-1.5 hours. After solid-liquid separation, impurity-removed liquid and filter residue are obtained. In the impurity-removed liquid, the total concentration of nickel, cobalt and manganese is 60-80 g / L, and the concentration of iron and aluminum is ≤0.1 mg / L. The filter residue includes graphite, iron-aluminum hydroxide and calcium salt. (2) The pH of the impurity removal solution is controlled to 4.9-5.3, and then the impurity removal solution is extracted with manganese extractant to obtain a manganese-loaded organic phase and a first raffinate; the first raffinate includes cobalt, magnesium, nickel and lithium; the concentrations of calcium, copper, zinc and manganese in the first raffinate are all less than 1.5 mg / L; the extraction method of manganese extraction is multi-stage countercurrent extraction, with 8-9 extraction stages; the manganese extractant includes P2O4; (3) The manganese-supported organic phase is back-extracted with hydrochloric acid to obtain waste copper-manganese liquid; after removing copper and zinc from the waste copper-manganese liquid with sodium sulfide, it is extracted and back-extracted with C272 extractant to obtain battery-grade manganese sulfate product. The pH of the first raffinate is controlled to 3.7-4.1, and then cobalt extraction is performed on the first raffinate using a cobalt extractant to obtain a cobalt-supported organic phase and a second raffinate; the second raffinate includes magnesium, nickel, and lithium; the concentration of cobalt in the second raffinate is less than 200 mg / L; the cobalt extraction method is multi-stage countercurrent extraction, with 10-11 extraction stages; the cobalt extractant includes P507; (4) The cobalt-supported organic phase is back-extracted with a sulfuric acid solution of concentration 5-6N to obtain a back-extract, and then the back-extract is purified with P204 extractant to obtain battery-grade cobalt sulfate product. The second raffinate is treated with resin to remove phosphorus and fluoride, and then the pH of the second raffinate is adjusted to 5-5.

5. Nickel extraction is then performed on the second raffinate using a DY319 organic phase to obtain a nickel-loaded organic phase and a third raffinate. The DY319 organic phase includes a DY319 extractant and a diluent, the diluent comprising sulfonated kerosene and / or butyl acetate. The volume concentration of DY319 in the DY319 organic phase is 30-45%. During the nickel extraction, the volume ratio of the DY319 organic phase to the second raffinate is (1-10):(10-1). The nickel extraction is performed using a multi-stage countercurrent extraction method, with 11-13 extraction stages. During the nickel extraction, the solution temperature is 20-25℃, and the mixing time is 5-8 minutes. The nickel concentration in the third raffinate is less than 1 mg / L. The lithium concentration in the nickel-loaded organic phase is less than 1.5 mg / L. (5) The nickel-supported organic phase is back-extracted with a sulfuric acid solution of concentration 5-6N to obtain a back-extract, and then the back-extract is purified with P204 extractant to obtain battery-grade nickel sulfate product. Under stirring conditions, a precipitant is added to the third raffinate to adjust the pH to 11-11.

5. The reaction temperature is 40-50℃ to carry out a magnesium precipitation reaction. After solid-liquid separation, a lithium-enriched solution with a magnesium concentration ≤0.05mg / L is obtained. Then, a precipitant is added to the lithium-enriched solution to carry out a lithium precipitation reaction at a reaction temperature of 90-95℃. After aging, the solution is filtered, washed, and dried to obtain the lithium product.

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