A method for separating and recovering nickel and cobalt from ternary smut

Abstract

The application provides a method for separating and recovering nickel and cobalt from ternary smut, and the method comprises the following steps: performing acid leaching treatment on the ternary smut to obtain a leaching solution, adjusting the pH of the leaching solution to obtain a solution from which iron and aluminum are removed; mixing the solution from which iron and aluminum are removed with an oxidizing agent to perform a precipitation reaction to obtain a solution from which manganese is removed; performing extraction treatment on the solution from which manganese is removed by using an organic phase of an oxime extractant to obtain a nickel-cobalt-containing organic phase and a raffinate; and performing stripping treatment on the nickel-cobalt-containing organic phase to obtain a nickel-cobalt-rich solution. According to the method, most of the impurity ions in the leaching solution of the ternary smut can be removed by simple pH adjustment and oxidation, and then a suitable oxime extractant is selected to efficiently extract the nickel and cobalt ions in the solution, so that efficient separation of nickel and cobalt from other impurity ions is realized, and the loss of nickel and cobalt in the recovery process is small, and a high-purity nickel-cobalt solution can be obtained at a high recovery rate.

Description

Technical Field

[0001] This invention belongs to the field of resource recycling technology and relates to a method for separating and recovering nickel and cobalt from ternary black powder. Background Technology

[0002] With the rapid development of the new energy power battery industry, the production and scrap volume of ternary lithium batteries have been increasing year by year. Waste ternary lithium battery black powder is rich in precious metals such as nickel and cobalt, and has extremely high resource recycling value. The efficient, low-cost, and high-purity recovery of nickel and cobalt metals from ternary black powder can not only realize resource recycling and reduce mineral resource consumption, but is also a core link in the green and sustainable development of the power battery industry, and has important economic value and environmental significance.

[0003] Currently, the mainstream nickel-cobalt recycling process for ternary lithium batteries in the industry is mainly based on hydrometallurgy. The conventional process route is as follows: ternary lithium batteries are leached with sulfuric acid to obtain a mixed leachate containing nickel, cobalt, manganese, iron, aluminum, and lithium. After removing iron and aluminum impurities by pH adjustment and precipitation, a phosphorus-based extraction system is used for deep impurity removal and metal separation. Specifically, manganese impurities in the system are removed using P204 extractant, and nickel and cobalt are separated stepwise using phosphorus-based extractants such as P507 and Cyanex 272. Finally, nickel and cobalt salt products are obtained through back-extraction, concentration, and crystallization. This process technology is mature and suitable for industrial production, and is a common technical solution for recycling waste ternary lithium battery resources at this stage. However, there are still many unavoidable technical defects in practical applications.

[0004] First, traditional phosphorus extraction systems suffer from poor selectivity and high metal loss. Conventional phosphorus extractants such as P204 and P507 have low selectivity for metal ions, and are prone to nickel and cobalt co-extraction during manganese extraction, resulting in nickel and cobalt metal loss and generally low overall metal recovery rates. At the same time, these extractants cannot achieve simultaneous nickel and cobalt co-extraction, requiring multi-stage stepwise extraction processes. This results in numerous extraction stages, a lengthy process flow, large equipment investment, and high energy consumption, significantly increasing the production cost of nickel and cobalt recovery.

[0005] Secondly, traditional manganese removal processes have significant drawbacks. The industry commonly uses P204 extraction for manganese removal. This method is not only complex, but also prone to emulsification and the formation of three-phase compounds due to trace amounts of colloidal and suspended impurities in the feed solution, resulting in substantial loss of the organic phase and poor production stability. While some processes use oxidation precipitation of manganese, these often employ oxidants such as hydrogen peroxide and sodium chlorate. Hydrogen peroxide has poor stability and is prone to decomposition and gas generation, making phase separation difficult. Sodium chlorate introduces chloride ion impurities, corroding production equipment and degrading the extractant, severely impacting the purity of the final battery-grade nickel-cobalt product and failing to meet the production requirements of high-end lithium battery raw materials.

[0006] Furthermore, traditional extraction systems suffer from insufficient adaptability and stability. In existing technologies, oxime extractants are primarily used in copper metal extraction, leading to a technical bias among those skilled in the art that "nickel-cobalt recovery must use phosphorus extractants," with few records of their application in the recovery of ternary black powder nickel-cobalt. Conventional phosphorus extractants exhibit weak oxidation resistance and resistance to impurity interference. Faced with trace amounts of residual oxidizing substances in the system after manganese precipitation, they are prone to hydrolysis and degradation, resulting in short organic phase cycle life and high reagent replenishment costs. Simultaneously, single-extractant systems exhibit poor phase separation and are prone to emulsification, making them unsuitable for continuous industrial production.

[0007] Furthermore, traditional processes result in low product preparation efficiency and limited quality. The nickel-cobalt solution obtained from conventional phosphorus extraction and back-extraction has a low metal concentration, requiring an additional evaporation and concentration process, which is energy-intensive and cumbersome. Moreover, the system suffers from severe impurity entrainment, resulting in a high impurity content in the back-extraction solution, necessitating an additional deep refining process. This further prolongs the production process, reduces production efficiency, and makes it difficult to efficiently prepare high-purity battery-grade nickel-cobalt solutions.

[0008] In summary, existing ternary nickel-cobalt recovery processes generally suffer from problems such as lengthy processes, low metal recovery rates, high reagent consumption, poor production stability, insufficient product purity, and high overall production costs, making it difficult to simultaneously meet the industrial demands for efficient recovery, low-cost operation, and high-quality product output. Therefore, developing a simplified, highly selective, stable, and efficient ternary nickel-cobalt separation and recovery method suitable for continuous industrial production has become a pressing technical problem for those skilled in the art. Summary of the Invention

[0009] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a method for separating and recovering nickel and cobalt from ternary black powder. The method of this invention not only achieves efficient separation of nickel and cobalt from other impurity ions, but also minimizes the loss of nickel and cobalt during the recovery process, and can obtain a high-purity nickel and cobalt solution with a high recovery rate.

[0010] To achieve this objective, the present invention adopts the following technical solution: This invention provides a method for separating and recovering nickel and cobalt from ternary black powder, the method comprising the following steps: The ternary black powder was subjected to acid leaching to obtain a leachate. The pH of the leachate was adjusted to obtain an iron and aluminum removal solution. The iron and aluminum removal solution is mixed with an oxidant to carry out a precipitation reaction, thereby obtaining a manganese removal solution; The organic phase containing nickel and cobalt was extracted using an oxime extractant to remove manganese from the solution, yielding the nickel-cobalt organic phase and the raffinate. The nickel-cobalt-containing organic phase was back-extracted to obtain a nickel-cobalt-rich solution.

[0011] This invention first leaches valuable metals from ternary black powder using acid leaching. Iron and aluminum impurities are removed simply by adjusting the pH, achieving preliminary impurity removal. Then, manganese is efficiently removed from the solution through oxidation and precipitation in an aqueous phase, without introducing organic matter, thus protecting the activity of the subsequent oxime extractant and extending its lifespan. Next, an oxime extractant with high selectivity for nickel and cobalt is used to extract the manganese-removed solution, without extracting impurity ions such as Mn, Ca, Mg, and Li. This allows for efficient extraction of nickel and cobalt ions in the solution without requiring deep manganese removal, achieving efficient separation of nickel and cobalt from other impurity ions. Finally, a high-purity nickel-cobalt-rich solution is obtained through back-extraction.

[0012] Preferably, the leaching agent used in the acid leaching treatment includes sulfuric acid with a molar concentration of 1.8 mol / L to 2.2 mol / L, such as 1.8 mol / L, 1.9 mol / L, 2 mol / L, 2.1 mol / L, or 2.2 mol / L, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0013] Preferably, the acid leaching temperature is 55℃~65℃, for example: 55℃, 58℃, 60℃, 62℃ or 65℃, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0014] Preferably, the acid leaching time is 2h to 3h, for example: 2h, 2.2h, 2.5h, 2.8h or 3h, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0015] Preferably, the pH of the leachate is adjusted to be 4.5 to 5.5, for example: 4.5, 4.8, 5, 5.2 or 5.5, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0016] Preferably, the pH adjuster for adjusting the leachate includes calcium carbonate.

[0017] Preferably, the oxidant includes sodium persulfate.

[0018] This invention uses sodium persulfate as an oxidant. Sodium persulfate has a high standard oxidation potential and can completely oxidize divalent manganese into solid manganese dioxide precipitate at room temperature without heating or additional temperature adjustment. The manganese removal rate can reach over 99.5%, and the residual manganese content in the feed solution is extremely low. This prevents trace amounts of manganese from entering the subsequent oxime extraction system from the source, thus eliminating manganese co-extraction and organic phase poisoning.

[0019] Preferably, the molar ratio of the oxidant to manganese in the iron and aluminum removal solution is (3~5):1, for example: 3:1, 3.5:1, 4:1, 4.5:1 or 5:1, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0020] Preferably, the pH of the precipitation reaction is 5 to 6, for example: 5, 5.2, 5.5, 5.8 or 6, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0021] Preferably, the precipitation reaction time is 40 min to 60 min, for example: 40 min, 45 min, 50 min, 55 min or 60 min, etc., not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0022] Preferably, the oxime extractant includes LIX84-I.

[0023] The LIX84-I oxime extractant used in this invention is a highly efficient extractant for nickel and cobalt. It is suitable for use in weakly acidic to near-neutral feed solutions, and its pH range is perfectly matched with that of the feed solution after iron and aluminum removal and manganese precipitation. There is no need for significant acid / alkali adjustment. Moreover, since an oxidant was added in the previous steps, there is residual oxidant in the system. Conventional extractants may become ineffective due to residual oxidant. However, LIX84-I has good chemical stability and is not easily oxidized and degraded by residual oxidant. It does not release harmful ions into the aqueous phase. The nickel-cobalt rich solution obtained after back-extraction has extremely low impurity content, which directly meets the requirements of battery-grade nickel and cobalt and ternary precursor raw materials, without the need for subsequent deep refining.

[0024] Preferably, the organic phase of the oxime extractant further includes a modifier and a diluent.

[0025] Preferably, the modifier includes TBP (tributyl phosphate).

[0026] The LIX84-I used in this invention has a relatively high viscosity. In ternary feed solutions containing trace amounts of colloids and residual fine solids, it is prone to slow phase separation, interfacial emulsification, and the formation of flocculent three-phase substances. This invention reduces the overall viscosity of the organic phase and increases the interfacial tension between the oil and water phases by adding TBP as a modifier, thereby accelerating sedimentation and stratification. Moreover, LIX84-I has low solubility in diluents. TBP, being a polar co-solvent, can increase the solubility of LIX84-I in diluents, improve the stability of the extractant, and increase extraction efficiency.

[0027] Preferably, the diluent comprises sulfonated kerosene.

[0028] Preferably, the volume percentage of the oxime extractant in the organic phase of the oxime extractant is 8% to 12%, for example: 8%, 9%, 10%, 11% or 12%, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0029] Preferably, the volume percentage of the modifier in the organic phase of the oxime extractant is 5% to 8%, for example: 5%, 5.5%, 6%, 7% or 8%, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0030] This invention uses an organic phase system of LIX84-I compounded with TBP and sulfonated kerosene, which has strong selectivity for nickel and cobalt, good anti-emulsification and phase separation effects, high chemical stability of organic phase, and long cycle life.

[0031] Preferably, the pH of the extraction process is 5 to 5.5, for example: 5, 5.1, 5.2, 5.3, 5.4 or 5.5, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0032] Preferably, the extraction temperature is 35℃~40℃, for example: 35℃, 36℃, 37℃, 38℃, 39℃ or 40℃, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0033] Preferably, the extraction time is 6 min to 10 min, for example: 6 min, 7 min, 8 min, 9 min or 10 min, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0034] Preferably, the stripping agent in the stripping treatment includes sulfuric acid with a molar concentration of 1 mol / L to 1.5 mol / L, such as 1 mol / L, 1.1 mol / L, 1.2 mol / L, 1.4 mol / L or 1.5 mol / L, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0035] Preferably, the O / A ratio of the back-extraction process is (2.5~3.5):1, for example: 2.5:1, 2.8:1, 3:1, 3.2:1 or 3.5:1, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0036] Preferably, the temperature of the back-extraction process is 35℃~45℃, for example: 35℃, 38℃, 40℃, 42℃ or 45℃, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0037] Preferably, the back-extraction process takes 8 to 12 minutes, for example, 8 minutes, 9 minutes, 10 minutes, 11 minutes or 12 minutes, etc., and is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0038] 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.

[0039] Compared with the prior art, the present invention has the following beneficial effects: (1) The method described in this invention can remove most of the impurity ions in the ternary black powder leachate by simply adjusting the pH and oxidizing. Then, a suitable oxime extractant is selected to efficiently extract nickel and cobalt ions from the solution. This not only achieves efficient separation of nickel and cobalt from other impurity ions, but also results in less loss of nickel and cobalt during the recovery process, and a high purity nickel and cobalt solution can be obtained with a high recovery rate.

[0040] (2) The method for separating and recovering nickel and cobalt from ternary black powder described in this invention can obtain a nickel-cobalt rich solution with a concentration of 107.8 g / L or more, a nickel recovery rate of 92.4% or more, and a cobalt recovery rate of 89.9% or more. By adjusting the recovery conditions, the concentration of the nickel-cobalt rich solution can be obtained to be 118.9 g / L or more, with a nickel recovery rate of 97.9% or more and a cobalt recovery rate of 92.4% or more. Detailed Implementation

[0041] 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.

[0042] The scope of this invention can be defined by lower and upper limits. The selected lower and upper limits define the boundaries of a specific range. The range defined in this way can be defined by the inclusion or exclusion of endpoints. Any endpoint can be independently selected for inclusion or exclusion, and all lower and upper limits can be arbitrarily combined to form new ranges. That is, any lower limit can be combined with any upper limit to form an effective range. For example, if the ranges of 60~120 and 80~110 are listed for specific parameters, it should be understood that the ranges of 60~110 and 80~120 also fall within the scope of this invention. In addition, if the minimum range values ​​1 and 2 are listed, and the maximum range values ​​3, 4 and 5 are also listed, then all ranges of 1~3, 1~4, 1~5, 2~3, 2~4 and 2~5 fall within the scope of this invention. In this invention, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "0~5" means that all real numbers between 0 and 5 have been fully listed in this document, and "0~5" is only a shortened representation of this set of numerical combinations. When a parameter is expressed as an integer ≥2, it is equivalent to listing positive integers that meet the requirements, such as 2, 3, 4, 5, 6, 7, 8, 9, 10, etc. When a parameter is expressed as an integer selected from "2~10", it is equivalent to listing any integer among 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0043] In this invention, "a combination of at least two" refers to a quantity greater than or equal to 2 unless otherwise specified. For example, "any one or a combination of at least two" means that any one of the listed items can be selected, or a combination of at least two of the listed items formed in a manner that does not conflict and enables the implementation of this invention. In this invention, unless otherwise specified, the features or solutions corresponding to "and / or" cover any one of two or more related listed items, as well as any and all combinations of the related listed items. The arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. For example, "A and / or B" means a set consisting of A, B, and combinations of A and B, where "containing A and / or B" can be understood, depending on the context of the statement, as containing A, containing B, or simultaneously containing both A and B. In this invention, "optional" means that the corresponding feature, component, step or solution is not necessary, that is, it is selected from either "with" or "without". If there are multiple "optional" limitations in a technical solution, unless otherwise specified and there is no technical conflict or mutual constraint, each "optional" limitation is independent and does not affect the others.

[0044] In this invention, technical features or solutions described using open-ended terms such as "comprising" or "including" do not exclude additional non-conflicting elements beyond the listed elements unless otherwise specified. They are considered to disclose both closed-ended features or solutions consisting solely of the listed elements and open-ended features or solutions that may include additional non-conflicting elements beyond the listed elements. For example, if A includes a1, a2, and a3, unless otherwise specified, this means that A can consist only of a1, a2, and a3, or it can include other non-conflicting elements based on a1, a2, and a3. This corresponds to the disclosure of technical solutions such as "A consists of a1, a2, and a3," "A is selected from a1, a2, and a3," and "A not only includes a1, a2, and a3, but may also include other non-conflicting elements." All embodiments and optional embodiments of this invention, unless otherwise specified and without technical conflict, can be combined to form new technical solutions, and such combinations fall within the scope of this invention. The term "embodiment" as used in this invention means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment or implementation of the invention. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. Those skilled in the art can understand, explicitly and implicitly, that the embodiments described in this invention can be combined with other embodiments that do not conflict with the technology.

[0045] In this invention, the order in which the steps are written in the methods described in each embodiment does not imply a strict execution order. The actual execution order of each step should be determined according to its function and possible internal logic. Unless otherwise specified, all steps of this invention can be executed in the order in which they are written or in any order that does not conflict with the technology.

[0046] The mass percentage of various elements in the ternary black powder used in the embodiments and comparative examples of this invention is shown in Table 1: Table 1 Example 1 This embodiment provides a method for separating and recovering nickel and cobalt from ternary black powder, the method comprising the following steps: The ternary black powder was acid-leached at 60°C for 2.5 h using sulfuric acid with a molar concentration of 2 mol / L to obtain a leachate. The pH of the leachate was adjusted to 5 using calcium carbonate to obtain an iron and aluminum removal solution. The iron and aluminum removal solution was mixed with sodium persulfate (the molar ratio of manganese in sodium persulfate to that in the iron and aluminum removal solution was 4:1), and a precipitation reaction was carried out for 50 min at pH 5.5 to obtain a manganese removal solution. The manganese removal solution was extracted with an oxime-based organic phase (10% LIX84-I, 5% TBP, and the remainder sulfonated kerosene) at pH 5.2 and 38°C for 8 min, followed by standing for 5 min to obtain a nickel-cobalt-containing organic phase and raffinate. Using sulfuric acid with a molar concentration of 1.2 mol / L and controlling the O / A ratio to 3:1, the nickel-cobalt-containing organic phase was back-extracted at 40 °C for 10 min to obtain a nickel-cobalt-rich solution.

[0047] Example 2 This embodiment provides a method for separating and recovering nickel and cobalt from ternary black powder, the method comprising the following steps: The ternary black powder was acid-leached at 65°C for 3 hours using sulfuric acid with a molar concentration of 1.8 mol / L to obtain a leachate. The pH of the leachate was adjusted to 5.5 using calcium carbonate to obtain an iron and aluminum removal solution. The iron and aluminum removal solution was mixed with sodium persulfate (the molar ratio of manganese in sodium persulfate to that in the iron and aluminum removal solution was 3:1), and a precipitation reaction was carried out for 60 minutes at pH 6 to obtain a manganese removal solution. The manganese removal solution was extracted using an oxime-based organic phase (12% LIX84-I by volume, 8% TBP by volume, and the remainder sulfonated kerosene) at pH 5.5 and 35°C for 10 min, followed by standing for 5 min to obtain a nickel-cobalt-containing organic phase and raffinate. Using sulfuric acid with a molar concentration of 1 mol / L and controlling the O / A ratio at 2.5:1, the nickel-cobalt-containing organic phase was back-extracted at 45°C for 8 min to obtain a nickel-cobalt-rich solution.

[0048] Example 3 This embodiment provides a method for separating and recovering nickel and cobalt from ternary black powder, the method comprising the following steps: The ternary black powder was acid-leached at 55°C for 2 hours using sulfuric acid with a molar concentration of 2.2 mol / L to obtain a leachate. The pH of the leachate was adjusted to 4.5 using calcium carbonate to obtain an iron and aluminum removal solution. The iron and aluminum removal solution was mixed with sodium persulfate (the molar ratio of manganese in sodium persulfate to that in the iron and aluminum removal solution was 5:1), and a precipitation reaction was carried out for 40 minutes at pH 5 to obtain a manganese removal solution. The manganese removal solution was extracted with an oxime-based organic phase (8% LIX84-I, 6% TBP, and the remainder sulfonated kerosene) at pH 5 and 40°C for 6 min, followed by standing for 5 min to obtain a nickel-cobalt-containing organic phase and raffinate. Using sulfuric acid with a molar concentration of 1.5 mol / L and controlling the O / A ratio at 3.5:1, the nickel-cobalt-containing organic phase was back-extracted at 35°C for 12 min to obtain a nickel-cobalt-rich solution.

[0049] Example 4 The only difference between this embodiment and Example 1 is that the pH of the extraction treatment is 4.5, while the other conditions and parameters are exactly the same as in Example 1.

[0050] Example 5 The only difference between this embodiment and Example 1 is that the pH of the extraction treatment is 6, while the other conditions and parameters are exactly the same as in Example 1.

[0051] Example 6 The only difference between this embodiment and Example 1 is that the volume percentage of LIX84-I in the organic phase of the oxime extractant is 5%, while the other conditions and parameters are exactly the same as in Example 1.

[0052] Example 7 The only difference between this embodiment and Example 1 is that the volume percentage of LIX84-I in the organic phase of the oxime extractant is 15%, while the other conditions and parameters are exactly the same as in Example 1.

[0053] Comparative Example 1 The only difference between this comparative example and Example 1 is that after removing manganese with P204, nickel and cobalt are separated by stepwise extraction with P507 and Cyanex 272. All other conditions and parameters are exactly the same as in Example 1.

[0054] Performance testing: The purity of the nickel-cobalt-rich solutions obtained from the test examples and comparative examples was determined, and the nickel-cobalt recovery rate was calculated. The test results are shown in Table 2. Table 2 As can be seen from Table 2, as obtained from Examples 1 to 7, the method for separating and recovering nickel and cobalt from ternary black powder described in this invention can achieve a nickel-cobalt rich solution concentration of over 107.8 g / L, a nickel recovery rate of over 92.4%, and a cobalt recovery rate of over 89.9%. By adjusting the recovery conditions, the concentration of the nickel-cobalt rich solution can reach over 118.9 g / L, with a nickel recovery rate of over 97.9% and a cobalt recovery rate of over 92.4%.

[0055] A comparison of Examples 1 and 4-5 shows that in the method for separating and recovering nickel and cobalt from ternary black powder described in this invention, the pH of the extraction process affects the recovery effect. Controlling the pH of the extraction process between 5 and 5.5 results in better separation and recovery. The pH value of the extraction process needs to be strictly controlled. If the pH is too high, nickel and cobalt ions are prone to hydrolysis, leading to a decrease in recovery rate and an increased risk of impurity co-extraction, thus worsening the separation effect. If the pH is too low, oxime functional groups are protonated, losing their chelating and coordinating abilities, significantly reducing the nickel and cobalt extraction rate, worsening separation selectivity, leaving a large amount of valuable metals in the aqueous phase, decreasing the recovery rate, and long-term high-acid environment accelerates the hydrolytic degradation of LIX84-I, shortening the organic phase lifetime and increasing reagent consumption.

[0056] A comparison of Examples 1 and 6-7 shows that in the method for separating and recovering nickel and cobalt from ternary black powder described in this invention, the volume percentage of the oxime extractant in the organic phase of the extraction process affects the recovery effect. Controlling the volume percentage of the oxime extractant in the organic phase to 8%-12% results in better separation and recovery. The volume percentage of the oxime extractant in the organic phase needs to be properly controlled. If the percentage is too high, due to the limited solubility of LIX84-I in sulfonated kerosene, it is prone to crystallization at high concentrations. Simultaneously, the viscosity of the organic phase increases sharply, leading to a slower oil-water phase transition, which easily triggers emulsification, entrainment, and increases the formation of three phases. If the percentage is too low, there is insufficient effective chelating component in the organic phase, reducing the saturated loading capacity of nickel and cobalt. This increases the number of extraction stages when processing the same feed solution, and consequently increases the organic phase circulation volume and operating losses.

[0057] As can be seen from the comparison between Example 1 and Comparative Example 1, the LIX84-I extractant used in this invention has a significantly stronger chelation selectivity for nickel and cobalt than the P204 extractant. It hardly extracts any impurity ions and can obtain a high-purity nickel and cobalt solution. The P204 extractant can play a certain role in removing impurities, but it is not suitable as the main extractant for nickel and cobalt. It needs to be combined with subsequent stepwise extraction with P507 and Cyanex272. The extraction effect is similar to that of LIX84-I used in this application, but the process flow is more complicated and the pH of the system needs to be adjusted. The process difficulty and cost are significantly increased. Moreover, the extraction effect of extractants such as P204 is greatly reduced under the condition of oxides, and the adaptability is poor.

[0058] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for separating and recovering nickel and cobalt from ternary black powder, characterized in that, The method includes the following steps: The ternary black powder was subjected to acid leaching to obtain a leachate. The pH of the leachate was adjusted to obtain an iron and aluminum removal solution. The iron and aluminum removal solution is mixed with an oxidant to carry out a precipitation reaction, thereby obtaining a manganese removal solution; The organic phase containing nickel and cobalt was extracted using an oxime extractant to remove manganese from the solution, yielding the nickel-cobalt organic phase and the raffinate. The nickel-cobalt-containing organic phase was back-extracted to obtain a nickel-cobalt-rich solution.

2. The method as described in claim 1, characterized in that, The leaching agent used in the acid leaching treatment includes sulfuric acid with a molar concentration of 1.8 mol / L to 2.2 mol / L.

3. The method as described in claim 1 or 2, characterized in that, The acid leaching treatment temperature is 55℃~65℃; Preferably, the acid leaching treatment time is 2h to 3h.

4. The method according to any one of claims 1-3, characterized in that, The pH of the leachate is adjusted to 4.5-5.5; Preferably, the pH adjuster for adjusting the leachate includes calcium carbonate.

5. The method according to any one of claims 1-4, characterized in that, The oxidant includes sodium persulfate; Preferably, the molar ratio of the oxidant to the manganese in the iron and aluminum removal solution is (3~5):

1.

6. The method according to any one of claims 1-5, characterized in that, The pH of the precipitation reaction is 5-6; Preferably, the precipitation reaction takes 40 to 60 minutes.

7. The method according to any one of claims 1-6, characterized in that, The oxime extractant includes LIX84-I; Preferably, the organic phase of the oxime extractant further includes a modifier and a diluent; Preferably, the modifier includes TBP; Preferably, the diluent comprises sulfonated kerosene; Preferably, the volume percentage of the oxime extractant in the organic phase of the oxime extractant is 8% to 12%; Preferably, the volume percentage of the modifier in the organic phase of the oxime extractant is 5% to 8%.

8. The method according to any one of claims 1-7, characterized in that, The pH of the extraction process is 5-5.5; Preferably, the extraction temperature is 35℃~40℃; Preferably, the extraction process takes 6 to 10 minutes.

9. The method according to any one of claims 1-8, characterized in that, The stripping agent in the stripping process includes sulfuric acid with a molar concentration of 1 mol / L to 1.5 mol / L.

10. The method according to any one of claims 1-9, characterized in that, The O / A ratio for the back-extraction process is (2.5~3.5):1; Preferably, the temperature of the back-extraction treatment is 35℃~45℃; Preferably, the back-extraction process takes 8 to 12 minutes.

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