Process for the extraction of impurities from a transition metal solution

Abstract

This invention relates to the field of metal ion purification and refining, specifically to a method for extracting and removing impurities from a transition metal solution. The method involves mixing a transition metal M solution containing impurity element N with an extraction organic phase for extraction, yielding a raffinate enriched with transition metal M and a supported organic phase enriched with impurity element N. Transition metal M includes at least one ion selected from nickel, cobalt, and manganese; impurity element N includes at least one ion selected from Al, F, and Ca. When impurity element N contains F, an extraction aid is pre-added to adjust the Al / F molar ratio in the transition metal M solution to 1-3:1. The extraction active components in the extraction organic phase include extractant A and extractant B in a molar ratio of 1:2-5. This invention enables the selective separation of transition metal M and impurity element N.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of metal ion purification, in particular to the technical field of impurity removal from transition metal solutions. BACKGROUND

[0002] Transition metal solutions such as common nickel-cobalt-manganese salt solutions are core intermediate raw materials in the hydrometallurgical industry, and their purity directly determines the quality and performance of downstream products. However, in actual production processes such as ore smelting and secondary resource recovery, impurities such as calcium, aluminum, and fluorine often coexist and are difficult to achieve deep purification. If these impurities are not effectively removed, not only will they corrode production equipment, but they will also easily interfere with the crystallization of salt products, thereby significantly reducing the chemical performance of end materials such as precursors, and increasing the environmental pressure of wastewater treatment. Therefore, developing an efficient process for deep removal of calcium, aluminum, and fluorine from nickel-cobalt-manganese salt solutions is of great significance for improving the utilization value of nickel-cobalt-manganese resources.

[0003] Existing technologies for removing calcium, aluminum, and fluorine from nickel-cobalt-manganese salt solutions mostly use a step-by-step precipitation method, with an independent removal process for each impurity. For example, Chinese patent document CN118183854A discloses a method for preparing high-purity manganese sulfate from a manganese-containing solution using step-by-step precipitation. First, the pH is adjusted and manganese fluoride is added as a precipitant to remove calcium and magnesium, and then aluminum sulfate and a precipitant accelerator are added to remove fluorine. This method separates the removal of calcium and fluorine into two independent steps, requiring solid-liquid separation in between, which is a high-process flow and equipment investment, and valuable metals are easily lost by mechanical entrainment or physical adsorption during the precipitation process. Chinese patent document CN119706968A discloses a purification and impurity removal method for crude nickel-cobalt-manganese sulfate salt solution. This process also uses a step-by-step impurity removal route: first, use phosphate to adjust the pH to remove titanium, iron, and aluminum, then add a fluorine agent to remove calcium and magnesium, and finally add glacial rock minerals to adsorb fluorine. Although this method covers multiple impurities, it requires the addition of different reagents to precipitate each impurity one by one, resulting in high reagent consumption and the risk of introducing new impurity ions such as phosphorus and iron. In addition, Chinese patent document CN119746510A discloses a method for removing impurities from lithium-ion battery leaching solution. This method uses the route of "first removing aluminum, then adding fluorine to remove calcium, and finally removing fluorine": first, add iron powder and alkali to adjust the pH to remove copper and aluminum, then add an oxidizing agent to remove iron after solid-liquid separation, then add a fluorine-containing reagent to precipitate and remove calcium and magnesium, and finally use a fluorine removal material to adsorb excess fluorine. This process also fails to simultaneously remove calcium, aluminum, and fluorine impurities, and additionally introduces fluorine ions, which then need to be removed in an additional step. This "adding impurities to remove impurities" approach results in waste of reagents and redundancy in operations.

[0004] Furthermore, some technologies have attempted solvent extraction or resin adsorption, but these have still failed to achieve simultaneous removal of calcium, aluminum, and fluorine. For example, Chinese patent document CN117089705A discloses a method for recycling waste lithium battery materials, which uses a mixed extractant (Cy-302 and P204) to extract calcium and zinc. Although this method has good selectivity for specific metal cations such as calcium, it cannot simultaneously remove anionic fluorine. Chinese patent document CN117317428A discloses a resin series adsorption method, first using Hp3500 resin to remove fluorine, and then using Hp4040 resin to remove calcium. This method also divides impurity removal into different steps and requires multi-stage column operation. The resin is easily poisoned by complex solution environments, and regeneration is frequent.

[0005] In summary, the impurity removal efficiency and effectiveness of existing transition metal salt solutions still need to be improved, especially for systems containing multiple heterogeneous ions, where there is still considerable room for improvement in the efficiency and selectivity of one-step separation. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides an extraction and impurity removal method for transition metal solutions, aiming to improve the impurity removal efficiency and selectivity.

[0007] A method for extracting impurities from a transition metal solution involves mixing a transition metal M solution (also known as a transition metal solution) containing impurity element N with an extraction organic phase for extraction, resulting in a raffinate enriched with transition metal M and a loaded organic phase enriched with impurity element N.

[0008] Transition metal M includes at least one ion selected from nickel, cobalt, and manganese;

[0009] Impurity element N includes at least one ion from Al, F and Ca. When impurity element N contains F, an extraction aid is added beforehand to adjust the molar ratio of Al / F in the transition metal M solution to 1~3:1.

[0010] The extractable active ingredient in the extracted organic phase comprises extractant A and extractant B in a molar ratio of 1:2 to 5; wherein extractant A is a compound with the structure of Formula 1; and extractant B is a compound with the structure of Formula 2.

[0011] Formula 1;

[0012] Formula 2;

[0013] In Formula 1, R1 is a C1~C8 alkyl group, C4~C6 ... 10 The alkoxy or phenoxy group; R2 is H, C1~C8 alkyl, C4~C 10 The alkoxy or phenoxy group; M is H, Na, K or NH4;

[0014] In Formula 2, R3 and R4 are individually C1~C8 alkyl groups and C4~C6 alkyl groups. 10 alkoxy or phenoxy groups;

[0015] The extraction process is carried out at a temperature below 45℃ and at a pH of 2.0 to 5.0.

[0016] To address the problem of low separation efficiency and selectivity of transition metal M ions and impurity element N ions in solution, this invention innovatively pre-treats the solution to be treated based on the characteristics of the impurity element N to be separated (e.g., for difficult-to-treat F-containing solutions, the Al / F ratio in the system is pre-adjusted using an extraction aid). Subsequently, extraction is innovatively carried out under the combined extraction agent of Formula 1 and Formula 2 in the special ratio, and further combined with the joint control of pH and temperature during the extraction process. This achieves synergy, enabling selective separation of transition metal M and impurity element N, and improving its impurity removal efficiency and effect.

[0017] In this invention, the transition metal M in the solution exists in ionic form, and more specifically, in divalent ionic form.

[0018] In this invention, the transition metal M in the transition metal M solution can be a single ion, two ions, or three ions. Considering the universality of existing battery systems and the market for recycling battery material elements, the transition metal M includes cations of nickel, cobalt, and manganese.

[0019] In this invention, there are no particular requirements for the concentration of transition metal M in the transition metal M solution. For example, as an optional scheme, the concentration of transition metal M is 10~150 g / L; further, it can be 20~120 g / L.

[0020] In this invention, the anions in the transition metal M solution include at least one of sulfate ions, nitrate ions, and chloride ions.

[0021] In this invention, the impurity elements in the transition metal M solution exist in the form of stable single ions or complex ions.

[0022] In this invention, there are two implementation schemes depending on whether the transition metal M solution contains F. For example, Scheme A: The transition metal M solution is solution A without F (i.e., containing calcium and / or aluminum), and solution A can be directly subjected to the extraction described above. Scheme B: The transition metal M solution is solution B containing F. Solution B (the impurity element N in this solution is either a single F or a mixture of F- (calcium and / or aluminum) ions) can be pre-treated with an extraction aid to strictly control the Al / F molar ratio in the system to be 1~3:1, and then subsequent extraction treatment can be performed.

[0023] In this invention, for solution A, the extractant with the special ratio described in this invention is used, and the pH and temperature are controlled together during the extraction process, so that the selective separation of transition metals and impurity elements (calcium and / or aluminum) can be achieved.

[0024] However, for solution B, by innovatively pre-treating it with an extraction aid (adjusting the molar ratio of Al / F), and then combining it with the combined control of the proportion of the extractant, pH and temperature described in this invention, the selective separation of transition metals and impurity elements (F, and selectively including at least one of calcium and / or aluminum) can be achieved, enabling highly efficient selective separation of complex impurity elements in a single extraction step.

[0025] In this invention, for transition metal M solutions containing impurity elements N including Al, F, and Ca, existing technologies typically require multi-step step-by-step impurity removal. However, this invention, based on the aforementioned pretreatment and extraction with a combined extractant, and through the combined synergistic control of the Al / F ratio in the pretreatment, the ratio of Formula 1 and Formula 2 in the combined extractant, and the pH and temperature of the extraction, achieves a synergistic effect. This allows for the selective separation of transition metal M and multiple types of impurity elements N in a single extraction step, thus possessing greater industrial value.

[0026] Alternatively, in the transition metal M solution, the concentrations of Al and F are ≤5 g / L, ≤3 g / L, and ≤1 g / L. For example, alternatively, the concentrations of Al are 0.1–1 g / L, F are 0.2–1 g / L, and Ca are 0.1–0.5 g / L. Furthermore, for the aforementioned difficult-to-treat system containing high levels of F and Al-Ca, the process described in this invention can also achieve excellent extraction and separation efficiency and selectivity.

[0027] In this invention, the molar ratio of Al / F in the transition metal M solution is adjusted to 1.5~2.5:1 by adding an extraction aid; further, it can be 1.9~2.1:1. By controlling the aforementioned ratio, F and Al in the system can form a composite ion form that is conducive to efficient capture by the combined extractant. This, combined with other process parameters, further enhances the selective separation of transition metal M and impurity element N.

[0028] The extraction aid is at least one of aluminum sulfate, aluminum hydroxide, aluminum chloride, and aluminum nitrate.

[0029] The pH of the system was controlled between 2 and 5 when adjusting the molar ratio of Al / F.

[0030] In this invention, the combination of Formula 1 and Formula 2, combined with the special ratio control of Formula 1 and Formula 2, with Formula 2 as the main component, can address the problem of selective separation of transition metal M and impurity element N in this invention. It can be combined with other operations and parameters to further enhance the separation selectivity of transition metal M and impurity element N.

[0031] In this invention, the extracted organic phase further includes a hydrophobic diluent, including aviation kerosene, sulfonated kerosene, No. 260 solvent oil, GV-18A, Escaid 110, and C8~C. 13 At least one of the higher alcohols.

[0032] In this invention, the concentration of Formula 1 in the extracted organic phase is 0.1~0.8 mol / L; further, it can be 0.2~0.6M; and even further, it can be 0.3~0.5M.

[0033] In this invention, the O / A ratio is 1~3:1 during the extraction process.

[0034] In this invention, the temperature during the extraction process is 5~25℃, further preferably 10~20℃, and even more preferably 14~20℃. Research in this invention shows that at this preferred temperature, it can be further combined synergistically with the extraction conditions described in this invention, potentially leading to an unexpected further enhancement of the separation selectivity between metal M and impurity N.

[0035] Preferably, the pH of the extraction process is 2.5 to 4.5; more preferably 2.8 to 3.6. At this preferred pH, it can be further combined synergistically with the extraction conditions described in this invention, and is expected to unexpectedly further enhance the separation selectivity of metal M and impurity N.

[0036] In this invention, the pH adjuster used in the extraction process can be a conventional alkaline or acidic component.

[0037] In this invention, the extraction method can be single-stage extraction or 2-10 stages of countercurrent extraction. Considering process efficiency, single-stage extraction can be used.

[0038] In this invention, the supported organic phase can be acid-washed and regenerated as needed, and the regenerated organic phase can be recycled as an extraction organic phase.

[0039] Beneficial effects

[0040] 1) This invention, based on a synergistic extraction system and with specific control of component ratios, achieves simultaneous selective separation of aluminum, fluorine, and calcium impurities in nickel-cobalt-manganese salt solutions. Compared to traditional stepwise precipitation methods, this invention reduces reagent usage, simplifies operation steps, and significantly reduces entrainment losses of transition metals such as nickel, cobalt, and manganese. Compared to single-stage extraction systems, this invention not only achieves co-extraction of aluminum, fluorine, and calcium but also exhibits superior separation coefficients, effectively avoiding co-extraction of nickel, cobalt, and manganese.

[0041] 2) In this invention, for systems containing fluorine (F), an extraction aid is added before extraction to regulate the ion distribution in the solution, achieving simultaneous extraction of aluminum and fluorine. Secondly, by controlling the extraction equilibrium conditions, particularly by employing low-temperature control, the selective extraction of impurities from nickel, cobalt, and manganese is significantly improved by utilizing the differential effect of temperature on the extraction behavior of impurities and the main metal. This invention features a short process flow, low chemical reagent consumption, and is easily applicable to industrial applications. Detailed Implementation

[0042] To better understand the present invention, specific embodiments are described below, but the listed embodiments do not limit the scope of protection of the present invention.

[0043] The technical solution of this invention can achieve selective extraction and separation of transition metal M and impurity element N in solution. Considering the advantages of industrial implementation, this solution is also applicable to the selective separation of various complex types of transition metal M and impurity element N.

[0044] For example, as an optional solution, the present invention also provides a method for the simultaneous removal of aluminum, fluorine, and calcium from a nickel-cobalt-manganese salt solution, comprising the following steps:

[0045] An extraction aid is added to a nickel-cobalt-manganese salt solution containing aluminum, fluorine, and calcium impurity ions, and the molar ratio of Al / F in the solution is adjusted to 1~3:1; then it is mixed with the extractant for extraction, thereby obtaining a supported organic phase containing aluminum, fluorine, and calcium and a raffinate containing nickel, cobalt, and manganese.

[0046] The extractant consists of extractant A and extractant B in a molar ratio of 1:2~5;

[0047] The extraction process is carried out at a temperature below 45℃ and at a pH of 2.0 to 5.0.

[0048] The extraction aid is at least one of aluminum sulfate, aluminum hydroxide, aluminum chloride, and aluminum nitrate.

[0049] In this invention, adjusting the molar ratio of aluminum to fluorine in the solution by adding an extraction aid is key to achieving aluminum-fluorine co-extraction. The extraction aid can transform aluminum and fluorine species that are difficult to extract in the solution into forms that are easily bound by the synergistic extractant, thereby achieving simultaneous removal of both.

[0050] This invention has found that the ratio of extractant A to extractant B in the organic phase is key to improving the selectivity of separating impurities from nickel, cobalt, and manganese, and increasing the separation coefficient.

[0051] The diluent in the organic phase is aviation kerosene, sulfonated kerosene, No. 260 solvent oil, GV-18A, Escaid 110, C8~C. 13 At least one of the higher alcohols.

[0052] The concentration of extractant A in the organic phase is 0.1~0.8 mol / L.

[0053] The equilibrium pH of the extraction process is 2.5–4.5; more preferably 2.8–3.6. The equilibrium pH can be controlled by saponifying and converting the organic phase. The saponification solution used in the saponification process is at least one of sodium hydroxide, sodium carbonate, and ammonia water; the saponification rate of the organic phase is 10%–90%; the conversion solution used in the conversion process is one of manganese salt solution, nickel salt solution, and cobalt salt solution, or a mixed salt solution of two or three of the above.

[0054] The temperature of the extraction process is controlled at 10~20℃.

[0055] This invention discovers that extraction temperature is one of the factors contributing to the efficient separation of aluminum, fluorine, and calcium from nickel, cobalt, and manganese. In this synergistic extraction system, temperature affects the extraction behavior of impurities and the main metals nickel, cobalt, and manganese differently. At conventional extraction temperatures of room temperature or higher, the separation of impurities from nickel, cobalt, and manganese is poor, resulting in high co-extraction rates of nickel, cobalt, and manganese. However, under the low-temperature conditions described in this invention, the co-extraction rates of nickel, cobalt, and manganese decrease significantly, while the extraction rates of aluminum, fluorine, and calcium remain essentially unchanged, thereby significantly improving the selectivity for separating impurities from the main metals.

[0056] The extraction operation of this invention can be implemented using existing methods and equipment. The number of extraction stages is greater than or equal to 1 stage; preferably 2 to 10 stages; preferably, when the number of extraction stages is greater than or equal to 2 stages, the extraction method is countercurrent extraction; preferably, during the extraction process, the volume flow ratio of the organic phase to the aqueous phase is 1:10 to 10:1.

[0057] In this invention, a detergent is used to wash the organic phase loaded with impurities in order to recover transition metals such as nickel, cobalt, and manganese that are physically entrained or co-extracted.

[0058] The detergent is an aqueous solution of at least one inorganic acid, such as sulfuric acid, nitric acid, or hydrochloric acid, containing a corresponding nickel-cobalt-manganese salt solution. + The concentration is 0.1~2 mol / L. The number of washing stages is greater than or equal to 1; preferably 2~5 stages. Preferably, when the number of washing stages is greater than or equal to 2, the washing method is countercurrent washing; preferably, during the washing process, the volume ratio of organic phase to aqueous phase is 5:1~30:1.

[0059] In this invention, a back-extraction agent is used to back-extract the washed organic phase to achieve the cyclic regeneration of the loaded organic phase and obtain a blank organic phase.

[0060] The stripping agent is an aqueous solution of at least one inorganic acid selected from hydrochloric acid, nitric acid, and sulfuric acid, and its H+... + The concentration is 0.1~4 mol / L; the number of back-extraction stages in the back-extraction process is greater than or equal to 1 stage; preferably 2~5 stages. Preferably, when the number of back-extraction stages is greater than or equal to 2 stages, the back-extraction method is countercurrent back-extraction; preferably, during the back-extraction process, the volume ratio of the organic phase to the aqueous phase feed liquid is 5:1~20:1.

[0061] In the embodiments, the distribution ratio D, separation coefficient β, and extraction rate E (%) are calculated according to equations (1) to (3), respectively:

[0062] ;

[0063] ;

[0064] ;

[0065] In equation (1), C O C R β represents the concentration of ions in the supported organic phase and the raffinate, respectively; in equation (2), β N / M D represents the separation coefficient between impurity N and transition metal element M (such as nickel, cobalt, and manganese). N D M They represent the distribution ratios of impurities to nickel, cobalt, and manganese, respectively; in equation (3), C F C R V represents the concentration of ions in the feed solution and the raffinate, respectively. F V R These represent the volumes of the feed liquid and the raffinate, respectively.

[0066] Example 1

[0067] Aqueous phase: Nickel-cobalt-manganese sulfate solution containing 58.15 g / L nickel, 21.64 g / L cobalt, 32.44 g / L manganese, 0.34 g / L aluminum, 0.71 g / L fluorine, and 0.26 g / L calcium.

[0068] Organic phase: includes a synergistic extractant and a diluent, wherein extractant A is of formula 1A ( ) ester, concentration of 0.4 mol / L; extractant B is formula 2A ( The concentration was 0.8 mol / L; the diluent was sulfonated kerosene.

[0069] Extraction conditions: The organic phase was contacted with aqueous feed solutions of different Al / F ratios (1#~3#) for single-stage extraction. The experiments were numbered 1#, 2#, and 3#, respectively. Saponification was performed using 10 mol / L sodium hydroxide solution, with the equilibrium pH controlled at 3.2, an O / A ratio of 1:1, a extraction time of 10 min, and a temperature of 15℃.

[0070] Among them, the Al / F molar ratio of the aqueous phase #1 is 0.34:1;

[0071] Phase 2 is an aqueous phase with added extraction aid (aluminum sulfate), and its Al / F molar ratio is 1:1;

[0072] The No. 3 aqueous phase is an aqueous phase with added extraction aid (aluminum sulfate), and its Al / F molar ratio is 2:1;

[0073] The results of the extraction selectivity experiments are shown in Table 1.

[0074] Table 1 Extraction effect of Example 1 ;

[0075] Note: M refers to the total amount of transition metal M (nickel, cobalt, and manganese in this case).

[0076] As shown in Table 1, the extraction rates of aluminum and fluorine were extremely low (only 5.88% and 4.22%, respectively) without the addition of extraction aids (1#), making it difficult to effectively remove impurities. In contrast, the extraction effect was significantly improved after adding extraction aids. The extraction rates of aluminum and fluorine were greatly increased after adding extraction aids, especially when aluminum sulfate was added to adjust the molar ratio of aluminum to fluorine in the solution to 2:1 (3#). The single-stage extraction rates of aluminum and fluorine were significantly increased, reaching 87.65% and 93.66%, respectively, while the separation coefficient β... Al / M and β F / M The values ​​also jumped significantly from 5.09 and 3.59 without the addition to 542.07 and 1129.02, respectively. Therefore, adjusting the Al / F ratio in the feed solution by adding extraction aids is the key to achieving efficient co-extraction of aluminum and fluorine. To ensure excellent impurity removal, the Al / F ratio in the feed solution before extraction should be ≥2.

[0077] Example 2

[0078] Aqueous phase: Nickel cobalt manganese sulfate solution, with the same composition as in Example 1.

[0079] Organic phase: includes synergistic extractant and diluent, wherein extractant A is formula 1A with a concentration of 0.4 mol / L; extractant B is formula 2A with concentrations of 1.2 mol / L and 1.6 mol / L, respectively; and diluent is sulfonated kerosene.

[0080] Extraction conditions: The organic phases with different ratios were contacted with aqueous solutions containing aluminum sulfate (with the addition of extraction aid) to adjust the aluminum to fluorine molar ratio to 2:1 for single-stage extraction. Experiments were numbered 1# and 2#. Saponification was performed using 10 mol / L sodium hydroxide solution, with the equilibrium pH controlled at 3.2, an O / A ratio of 1:1, a extraction time of 10 min, and a temperature of 15℃. The experimental results are shown in Table 2.

[0081] Table 2 Extraction effect of Example 2 ;

[0082] The experimental results in Table 2 show that the ratio of synergistic extractants significantly affects the separation effect. When the molar ratio of extractant A to extractant B is adjusted to 1:2 or higher, the extraction rates of aluminum, fluorine, and calcium all increase to over 80%, while the co-extraction rate of manganese decreases significantly to below 4%. These results indicate that the combined use of extractant A and extractant B produces a significant synergistic effect, enabling the selective separation of aluminum, calcium, and fluorine impurities from nickel, cobalt, and manganese. Therefore, to ensure good separation results, the molar ratio of extractant A to extractant B in the organic phase synergistic extractant should be controlled at 1:2 or higher.

[0083] Example 3

[0084] Aqueous phase: Nickel-cobalt-manganese sulfate solution containing 32.42 g / L nickel, 4.39 g / L cobalt, 4.83 g / L manganese, 0.26 g / L aluminum, 0.52 g / L fluorine, and 0.17 g / L calcium.

[0085] Organic phase: includes a synergistic extractant and a diluent, wherein extractant A is of formula 1B ( The concentration of extractant B is 0.4 mol / L; extractant B is formula 2B ( The concentration was 1.2 mol / L; the diluent was No. 260 solvent oil.

[0086] Extraction conditions: Aluminum sulfate was added as an extraction aid to adjust the aluminum to fluorine molar ratio of the aqueous phase to 2:1. The organic phase was contacted with the aqueous phase for three-stage countercurrent extraction. Saponification was performed using concentrated ammonia. The equilibrium pH was controlled at 2.5, 3.0, 3.5, 4.0, 4.5, 2.0 or 5.0. The experiments were numbered 1#, 2#, 3#, 4#, 5#, 6# and 7#, respectively. The O / A ratio was 1:1, the time was 10 min, and the temperature was 15℃. The experimental results are shown in Table 3.

[0087] Table 3 Extraction effect of Example 3 ;

[0088] As shown in Table 3, the equilibrium pH value has different effects on the extraction behavior of impurities aluminum, fluorine, and calcium, and valuable metals nickel, cobalt, and manganese during the extraction process. With increasing equilibrium pH, the extraction rates of nickel, cobalt, and manganese gradually increase. When the pH is 3.0, the extraction rates of nickel, cobalt, and manganese are only 0.02%, 0.11%, and 3.73%, respectively, with relatively small co-extraction losses. However, when the pH rises to 4.5, the extraction rates of the three increase to 3.45%, 2.05%, and 22.98%, respectively, with significant co-extraction losses. In contrast, when the equilibrium pH is 3.0 and 3.5, the extraction rates of aluminum, fluorine, and calcium all reach over 99%. Further increasing the pH value will not only lead to a significant increase in the co-extraction losses of nickel, cobalt, and manganese, but also cause a decrease in the calcium extraction rate. Therefore, to ensure high recovery rates of nickel, cobalt, and manganese and excellent impurity removal effects, the equilibrium pH value of the aqueous phase during the extraction process should be controlled between 2.8 and 3.6.

[0089] Example 4

[0090] Aqueous phase: a nickel-cobalt-manganese chloride solution containing 21.53 g / L nickel, 3.83 g / L cobalt, 10.42 g / L manganese, 0.75 g / L aluminum, 0.67 g / L fluorine, and 0.38 g / L calcium.

[0091] Organic phase: includes a synergistic extractant and a diluent, wherein extractant A is of formula 1B with a concentration of 0.3 mol / L; extractant B is of formula 2C ( The concentration was 0.6 mol / L; the diluent was aviation kerosene.

[0092] Extraction conditions: Aluminum chloride was added as an extraction aid to adjust the aluminum to fluorine molar ratio of the aqueous phase to 2:1. The organic phase was contacted with the aqueous phase for four-stage countercurrent extraction. Saponification was performed using 10 mol / L sodium hydroxide solution, followed by transfer to saponification using nickel chloride solution. The controlled temperatures were 10℃, 15℃, 20℃, 30℃, and 40℃, and the experiment numbers were 1#, 2#, 3#, 4#, and 5#, respectively. The equilibrium pH was 3.0, the O / A ratio was 2:1, and the extraction time was 10 min. The experimental results are shown in Table 4.

[0093] Table 4 Extraction effect of Example 4 ;

[0094] As shown in Table 4, the extraction temperature significantly affects the separation of impurities aluminum, fluorine, and calcium from nickel, cobalt, and manganese. The extraction rates of each element generally increase with increasing temperature, but differences exist among different elements. The results indicate that the extraction rate of manganese increases significantly with increasing temperature, while the extraction rates of impurities show little change. At 20℃, the extraction rate of manganese is only 2.21%, but when the temperature rises to 30℃, the extraction rate increases sharply to 6.72%, leading to a significant decrease in separation selectivity. In contrast, at lower temperatures of 10–20℃, the extraction rates of impurities aluminum, fluorine, and calcium remain above 99%. Therefore, based on the difference in the extraction behavior of impurities and main metals due to temperature, the extraction temperature should be controlled within the range of 10–20℃.

[0095] Example 5

[0096] Aqueous phase: Nickel-cobalt sulfate solution containing 21.53 g / L nickel, 3.83 g / L cobalt, 0.36 g / L aluminum, 0.37 g / L fluorine, and 0.24 g / L calcium.

[0097] Organic phase: includes a synergistic extractant and a diluent, wherein extractant A is of formula 1A with a concentration of 0.4 mol / L; extractant B is of formula 2A with a concentration of 0.8 mol / L; and the diluent is Escaid110.

[0098] Extraction conditions: Aluminum sulfate was added as an extraction aid to adjust the aluminum to fluorine molar ratio of the aqueous feed to 2:1. The organic phase was contacted with the aqueous feed for a three-stage countercurrent extraction. Saponification was performed using 10 mol / L sodium hydroxide solution, followed by transfer to saponification using nickel sulfate solution. The extraction ratio (O / A) was 1:1, the extraction time was 10 min, the temperature was 20℃, and the outlet equilibrium pH was controlled at 3.5. The extracted loaded organic phase was washed with 0.2 mol / L sulfuric acid for a two-stage countercurrent wash at an O / A ratio of 15:1. The resulting aqueous phase was incorporated into the extraction feed. After washing, the organic phase was back-extracted with 2 mol / L hydrochloric acid for a three-stage countercurrent back-extraction at an O / A ratio of 10:1. The back-extracted organic phase was then saponified with 10 mol / L sodium hydroxide solution and returned to the extraction cycle.

[0099] Once the system reached stable equilibrium, the analysis data showed that the raffinate contained 0.00086 g / L aluminum, 0.0011 g / L fluorine, and 0.0011 g / L calcium; the back-extraction solution contained 10.62 g / L aluminum, 3.78 g / L fluorine, 2.35 g / L calcium, 0.015 g / L nickel, and 0.026 g / L cobalt. The extraction removal rates of aluminum, fluorine, and calcium were 99.76%, 99.70%, and 99.54%, respectively, while the loss rates of nickel and cobalt were only 0.0069% and 0.068%, respectively. This indicates that deep removal of aluminum, fluorine, and calcium impurities from nickel-cobalt sulfate solutions can be achieved with extremely low nickel and cobalt losses.

[0100] Example 6

[0101] Aqueous phase: manganese sulfate solution containing 32.93 g / L manganese, 0.43 g / L aluminum, and 0.31 g / L calcium.

[0102] Organic phase: includes synergistic extractant and diluent, wherein extractant A is formula 1A with a concentration of 0.2 mol / L; extractant B is formula 2A with a concentration of 0.4 mol / L; and diluent is sulfonated kerosene.

[0103] Extraction conditions: The solution is fluorine-free, and no extraction aids are added. The organic phase and aqueous feed are subjected to a three-stage countercurrent extraction, with saponification using 10 mol / L sodium hydroxide solution and subsequent soap transfer using manganese sulfate solution. The extraction ratio (O / A) is 2:1, the extraction time is 10 min, the temperature is 20℃, and the outlet equilibrium pH is controlled at 3.0. The extracted loaded organic phase is then subjected to a two-stage countercurrent wash using 0.2 mol / L sulfuric acid, with a washing ratio (O / A) of 15:1. The resulting aqueous phase is incorporated into the extraction feed. After washing, the organic phase is subjected to a three-stage countercurrent back-extraction using 2 mol / L hydrochloric acid, with a back-extraction ratio (O / A) of 10:1. The back-extracted organic phase is then saponified with 10 mol / L sodium hydroxide solution and returned to the extraction cycle for reuse.

[0104] Once the system reached stable equilibrium, the analysis data showed that the raffinate contained 0.0012 g / L aluminum and 0.0013 g / L calcium; the back-extraction solution contained 4.49 g / L aluminum, 3.28 g / L calcium, and 5.06 g / L manganese. The extraction removal rates of aluminum and calcium were 99.72% and 99.58%, respectively, while the manganese loss rate was only 1.50%, indicating that deep removal of aluminum and calcium impurities from manganese sulfate solution can be achieved with extremely low manganese loss.

[0105] Example 7

[0106] Aqueous phase: Nickel sulfate solution containing 61.88 g / L nickel, 0.12 g / L aluminum, and 0.39 g / L fluorine.

[0107] Organic phase: includes synergistic extractant and diluent, wherein extractant A is formula 1A with a concentration of 0.3 mol / L; extractant B is formula 2B with a concentration of 0.6 mol / L; and diluent is sulfonated kerosene.

[0108] Extraction conditions: Aluminum sulfate, an extraction aid and conversion agent, was added to adjust the aluminum to fluorine molar ratio in the aqueous feed to 2.5:1. The organic phase was subjected to a three-stage countercurrent extraction in contact with the aqueous feed, followed by saponification with 10 mol / L sodium hydroxide solution and subsequent conversion with nickel sulfate solution. The extraction ratio (O / A) was 1:1, the extraction time was 10 min, the temperature was 20℃, and the outlet equilibrium pH was controlled at 3.5. The resulting loaded organic phase was subjected to a two-stage countercurrent washing with 0.1 mol / L sulfuric acid at an O / A ratio of 15:1. The resulting aqueous phase was incorporated into the extraction feed. The washed organic phase was then subjected to a three-stage countercurrent back-extraction with 1 mol / L sulfuric acid at an O / A ratio of 10:1. After back-extraction, the organic phase was saponified with 10 mol / L sodium hydroxide solution and returned to the extraction cycle.

[0109] Once the system reached stable equilibrium, the analysis data showed that the raffinate contained 0.0010 g / L aluminum and 0.0019 g / L fluorine; the back-extraction solution contained 13.86 g / L aluminum, 3.93 g / L fluorine, and 0.010 g / L nickel. The extraction removal rates of aluminum and fluorine were 99.17% and 99.51%, respectively, while the nickel loss rate was only 0.0016%, indicating that deep removal of aluminum and fluorine impurities from nickel sulfate solution can be achieved with extremely low nickel loss.

[0110] Comparative Example 1

[0111] Compared with Example 1, the only difference is that Formula 1A is missing in the extractant, and the missing amount is made up by equimolar use of Formula 2A. All other operations and parameters are the same as in Example 1. The results are shown in Table 5.

[0112] Table 5 Extraction effect of Comparative Example 1 ;

[0113] As shown in Table 5, the extractant B alone has virtually no extraction effect on the elements in the solution. To achieve the desired impurity removal effect, it needs to be used in conjunction with extractant A.

[0114] Comparative Example 2

[0115] Compared with Example 1, the only difference is that Formula 2A is missing from the extractant, and the missing amount is made up by equimolar replacement with Formula 1A. All other operations and parameters are the same as in Example 1. The results are shown in Table 6.

[0116] Table 6 Extraction effect of Comparative Example 2 ;

[0117] As shown in Table 6, replacing extractant B with extractant A in the organic phase improved the extraction rates of all elements, but significantly increased the co-extraction losses of nickel, cobalt, and manganese. Under the condition that the Al / F ratio is greater than 1, the separation coefficient β...Al / M β F / M and β Ca / M The value also decreased significantly, indicating that the reduction of extractant B is not conducive to the extraction and separation of impurities and valuable components.

[0118] Comparative Example 3

[0119] Compared with Example 1, the only difference is that the total amount of Formula 1A and Formula 2A in the extractant is the same as in Example 1, but the molar ratio of Formula 1A to Formula 2A is 1:1; all other operations and parameters are the same as in Example 1. The results are shown in Table 7.

[0120] Table 7 Extraction effect of Comparative Example 3 ;

[0121] As shown in Table 7, under the condition that the molar ratio of extractant A to extractant B is 1:1, the extraction rate of each element is slightly improved, but the separation coefficient β is lower. Al / M β F / M and β Ca / M The decrease indicates that controlling the ratio of extractant A to extractant B is key to achieving the extraction and separation of impurities and valuable components.

[0122] Comparative Example 4

[0123] Compared with Example 3, the only difference is that the equilibrium pH was controlled at 1.5; all other operations and parameters were the same as in Example 3. The results are shown in Table 8.

[0124] Table 8 Extraction effect of Comparative Example 4 ;

[0125] As shown in Table 8, when the equilibrium pH is below 2, the extraction rates of aluminum, fluorine, and calcium are low, and the impurity removal effect cannot be achieved.

Claims

1. A method for extracting and removing impurities from a transition metal solution, characterized in that, The solution of transition metal M containing impurity element N is mixed with the extraction organic phase for extraction to obtain raffinate enriched with transition metal M and supported organic phase enriched with impurity element N. Transition metal M includes at least one ion selected from nickel, cobalt, and manganese; Impurity element N includes at least one ion from Al, F and Ca. When impurity element N contains F, an extraction aid is added beforehand to adjust the molar ratio of Al / F in the transition metal M solution to 1~3:

1. The extractable active ingredient in the extracted organic phase comprises extractant A and extractant B in a molar ratio of 1:2 to 5; wherein extractant A is a compound with the structure of Formula 1; and extractant B is a compound with the structure of Formula 2. Formula 1; Formula 2; In Formula 1, R1 is a C1~C8 alkyl group, C4~C6 ... 10 The alkoxy or phenoxy group; R2 is H, C1~C8 alkyl, C4~C 10 The alkoxy or phenoxy group; M is H, Na, K or NH4; In Formula 2, R3 and R4 are individually C1~C8 alkyl groups and C4~C6 alkyl groups. 10 alkoxy or phenoxy groups; The extraction process is carried out at a temperature below 45℃ and at a pH of 2.0 to 5.

0.

2. The extraction and impurity removal method for transition metal solutions as described in claim 1, characterized in that, In the solution of transition metal M, transition metal M includes cations of nickel, cobalt and manganese; wherein the concentration of transition metal M is 10~150 g / L; The anions in the solution of transition metal M include at least one of sulfate ions, nitrate ions, and chloride ions.

3. The extraction and impurity removal method for transition metal solutions as described in claim 1, characterized in that, Impurity element N includes Al, F and Ca; wherein the concentration of Al is ≤5 g / L, the concentration of F is ≤3 g / L and the concentration of Ca is ≤1 g / L.

4. The extraction and impurity removal method for transition metal solutions as described in claim 3, characterized in that, The molar ratio of Al / F in the transition metal M solution was adjusted to 1.5~2.5:1 by adding extraction aids; The extraction aid is at least one of aluminum sulfate, aluminum hydroxide, aluminum chloride, and aluminum nitrate. The pH of the system was controlled between 2 and 5 when adjusting the molar ratio of Al / F.

5. The extraction and impurity removal method for transition metal solutions as described in claim 1, characterized in that, The extracted organic phase also contains hydrophobic diluents, including aviation kerosene, sulfonated kerosene, No. 260 solvent oil, GV-18A, Escaid 110, and C8~C. 13 At least one of the higher alcohols.

6. The extraction and impurity removal method for transition metal solutions as described in claim 5, characterized in that, In the extracted organic phase, the concentration of Formula 1 is 0.1~0.8 mol / L.

7. The extraction and impurity removal method for transition metal solutions as described in claim 1, characterized in that, The extraction method is either single-stage extraction or countercurrent extraction, where the O / A ratio is 1~3:

1.

8. The extraction and impurity removal method for transition metal solutions as described in claim 1, characterized in that, The temperature during the extraction process is 5~25℃.

9. The extraction and impurity removal method for transition metal solutions as described in claim 1, characterized in that, The pH during the extraction process is 2.8 to 3.

6.

10. The extraction and impurity removal method for transition metal solutions according to any one of claims 1 to 9, characterized in that, The supported organic phase is regenerated by acid washing, and the regenerated organic phase is recycled as the extraction organic phase.

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