A method and system for extracting scandium from a cobalt-nickel hydroxide solution containing scandium

Abstract

This application provides a method and system for extracting scandium from a scandium-containing cobalt-nickel hydroxide solution, belonging to the field of heavy metal recovery technology. The method includes the following steps: extracting the scandium-containing cobalt-nickel hydroxide solution with an organic extractant to obtain a scandium-containing organic phase; washing the scandium-containing organic phase to obtain a purified organic phase; back-extracting the purified organic phase with hydrochloric acid to obtain a scandium-containing back-extract and a back-extracted organic phase; performing scandium extraction treatment on the scandium-containing back-extract to obtain scandium oxide; and regenerating the back-extracted organic phase sequentially with sodium carbonate and dilute sulfuric acid to obtain a regenerated organic extractant, which is then reused. This application first sequentially washes the chlorine with sodium carbonate and sulfuric acid solutions, solving the emulsification problem in the extraction, washing, and back-extraction stages caused by washing with sodium carbonate solution. Furthermore, compared to directly using sulfuric acid solution for washing, this application uses less sulfuric acid in the regeneration stage, preventing phase miscibility during the washing process.

Description

Technical Field

[0001] This invention relates to the field of heavy metal recovery technology, specifically to a method and system for extracting scandium from a scandium-containing cobalt-nickel hydroxide solution. Background Technology

[0002] In the hydrometallurgical refining of scandium, amine extractants are a good choice. CN117701920A discloses a method for recovering scandium. This patent utilizes a secondary amine extractant to recover scandium from laterite nickel ore. The extractant has high selectivity for scandium and can be back-extracted using weak acids and weak bases. Long-chain primary amine extractants also have high selectivity for scandium, and back-extraction can be achieved using weak acids and weak bases. They are also less prone to emulsification and are already suitable for large-scale application in scandium extraction and purification.

[0003] However, during the back-extraction process, using a weak base can cause a three-phase problem, leading to difficulties in phase separation. In production lines, long-chain primary amine extractants are back-extracted in a slightly acidic environment. Sulfuric acid solution is ineffective, while hydrochloric acid solution is more effective and yields a higher extraction rate. However, when back-extracting long-chain primary amine extractants in acidic systems, they may form ion-pair complexes or amine salt complexes (such as R-NH3Cl) with chloride ions, causing chloride ions to be entrained into the organic phase. The hazards of chloride ions to the extraction system include: 1. Residual Cl in the organic phase... - Or the complex may compete with the target metal ions for the active sites of the extractant, leading to a decrease in the metal extraction rate in subsequent cycles; 2. The extraction capacity of the extractant depends on the pH of the system, Cl... - Accumulation may alter local acidity and disrupt the extraction equilibrium. Summary of the Invention

[0004] In view of the technical problems existing in the background art, this application provides a method and system for extracting scandium from a scandium-containing cobalt-nickel hydroxide solution, aiming to solve the problem of Cl in the organic phase being extracted during hydrochloric acid back-extraction. - Remaining technical issues.

[0005] In a first aspect, embodiments of this application provide a method for extracting scandium from a scandium-containing cobalt-nickel hydroxide solution, comprising the following steps:

[0006] (1) The scandium-containing cobalt-nickel hydroxide solution was extracted with an organic extractant to obtain a cobalt-nickel solution and a scandium-containing organic phase;

[0007] (2) The scandium-containing organic phase was washed with a detergent to obtain washing waste liquid and purified organic phase;

[0008] (3) Hydrochloric acid was used as the back-extraction agent to back-extract the purified organic phase, resulting in a scandium-containing back-extraction solution and a back-extracted organic phase;

[0009] (4) Scandium extraction is performed on the scandium-containing back-extraction solution to obtain scandium oxide;

[0010] The back-extracted organic phase is regenerated sequentially using sodium carbonate and dilute sulfuric acid to obtain a regenerated organic extractant. The regenerated organic extractant is then reused in step (1) to extract a solution containing scandium-containing cobalt-nickel hydroxide.

[0011] In the technical solution of this application embodiment, due to the large amount of Cl remaining in the back-extracted organic phase... - Directly reusing the back-extracted organic phase would lead to a decrease in the metal extraction rate in subsequent cycles, so the back-extracted organic phase was regenerated.

[0012] Chlorine is removed by washing with a sulfuric acid solution that has a higher concentration than hydrochloric acid. - In the initial stage, the extraction system operates stably. However, after a long period of operation, the acidity increases due to the continuous operation of the chlorine washing section. This causes organic miscibility during the chlorine washing process, resulting in the regenerated organic extractant carrying some sulfuric acid, which affects the stability of the entire extraction system. On the other hand, using a sulfuric acid solution with lower acidity for chlorine washing will lead to insufficient chlorine washing.

[0013] Chlorine is removed by washing with sodium carbonate solution alone. - In this case, compared to the sulfuric acid system for chlorine washing, CO3... 2- The polarity ratio of Cl - High, making it easier to extract Cl from the organic phase. - It washes off, but prolonged operation can lead to the accumulation of carbonate ions in the regenerated organic extractant. Furthermore, the extraction of scandium-containing cobalt-nickel hydroxide solution using the regenerated organic extractant is carried out under weakly acidic conditions. + It will react with CO3 in the regenerated organic extractant 2- The reaction generates bubbles, causing emulsification in the extraction, washing, and back-extraction sections, affecting the entire extraction process.

[0014] This application first uses sodium carbonate to wash the chlorine from the back-extracted organic phase, and then uses sulfuric acid solution to remove CO3. 2- This method solves the problem of emulsification in the extraction, washing, and back-extraction sections caused by using sodium carbonate solution for chlorine washing. At the same time, the method uses less sulfuric acid solution, which will not cause phase mixing during the chlorine washing process.

[0015] In some embodiments, the step of regenerating the back-extracted organic phase includes:

[0016] (41) The back-extracted organic phase was washed with sodium carbonate solution to obtain a dechlorinated organic phase and chlorine-containing waste liquid;

[0017] In step (41), the concentration of sodium carbonate solution is 0.4~1.5 mol / L, and the flow rate ratio of sodium carbonate solution to the back-extracted organic phase is (0.45~1.2):(1.2~1.5).

[0018] (42) CO3 was washed off the dechlorinated organic phase using dilute sulfuric acid. 2- This yields a regenerated organic extractant and a regenerated waste liquid;

[0019] In step (42), the concentration of dilute sulfuric acid is 2.25~2.5 mol / L, and the flow rate ratio of dilute sulfuric acid to dechlorinated organic phase is (0.3~0.35):(1.2~1.5).

[0020] In the technical solution of this application embodiment, under the condition of satisfying chlorine washing, the concentration of sodium carbonate solution is reduced as much as possible, thereby reducing the chlorine washing stage and the CO3 washing process. 2- The cost of auxiliary materials for this stage. Excessive CO3. 2- It will accumulate in organic matter, increasing the CO3 concentration during washing. 2- Difficulty.

[0021] This application uses high-concentration, low-flow-rate dilute sulfuric acid to wash CO3 from the dechlorinated organic phase. 2- High concentrations of dilute sulfuric acid affect CO3. 2- It has a good washing effect and will not cause emulsification in the extraction section. The low flow rate of dilute sulfuric acid can reduce the amount of sulfuric acid used and avoid sulfuric acid being carried in the organic extractant.

[0022] In some embodiments, during extraction in step (1), sulfuric acid is used to adjust the pH to 0.3-1.

[0023] In some embodiments, the scandium extraction process includes the following steps: adding oxalic acid to a scandium-containing back-extraction solution to obtain scandium oxalate precipitate, and filtering, washing, and calcining the scandium oxalate precipitate to obtain scandium oxide.

[0024] In some embodiments, the organic extractant includes a scandium extractant and a diluent, wherein the scandium extractant is a long-chain primary amine extractant, the diluent is n-dodecane, and the concentration of the organic extractant is 15% to 30%.

[0025] In some embodiments, the flow rate ratio of the scandium-containing cobalt-nickel hydroxide solution to the organic extractant in step (1) is (3.5~5.5):(1.2~1.5);

[0026] In step (2), the ratio of detergent flow rate to scandium-containing organic phase flow rate is (0.3~0.5):(1.2~1.5);

[0027] In step (3), the concentration of hydrochloric acid is 3.5~5 mol / L, and the ratio of hydrochloric acid to purified organic phase flow rate is (0.2~0.25):(1.2~1.5).

[0028] In the technical solution of this application embodiment, the washing section uses high-concentration, low-flow-rate sulfuric acid for washing, which can solve the emulsification problem in the washing section; in the back-extraction section, by increasing the flow rate of the back-extraction agent hydrochloric acid and ensuring that the volume ratio of the organic phase (O) and the aqueous phase (A) in the back-extraction section is O / A < 6.5, emulsification in the back-extraction section can be avoided.

[0029] In some embodiments, the detergent is dilute sulfuric acid with a concentration of 1.5~2.5 mol / L.

[0030] In some embodiments, H in the detergent + The concentration of H in the stripping agent is higher than that in the stripping agent. + concentration.

[0031] In the technical solution of this application embodiment, a high concentration of sulfuric acid is used in the detergent to prevent carbon dioxide from being generated in the back-extraction section, thus preventing emulsification.

[0032] Secondly, embodiments of this application provide a system for extracting scandium from a scandium-containing cobalt-nickel hydroxide solution, comprising:

[0033] An extraction unit is used to extract a solution containing scandium-containing cobalt-nickel hydroxide.

[0034] The washing unit is connected to the discharge end of the extraction unit and is used to wash the scandium-containing organic phase obtained by the extraction unit.

[0035] The back-extraction unit is connected to the discharge end of the washing unit and is used to back-extract the purified organic phase obtained from the washing unit.

[0036] The scandium extraction unit is connected to the aqueous phase outlet of the back-extraction unit and is used to extract scandium from the scandium-containing back-extraction solution obtained from the back-extraction unit.

[0037] The regeneration unit, connected to the organic phase outlet of the back-extraction unit, is used to sequentially wash the back-extracted organic phase obtained from the back-extraction unit with chlorine and CO3. 2- This yields a regenerated organic extractant;

[0038] The organic phase outlet of the regeneration unit is connected to the organic extractant inlet of the extraction unit.

[0039] In the technical solution of this application embodiment, the regeneration unit includes a chlorine washing unit and a CO3 washing unit arranged sequentially along the material flow direction. 2- The unit, the chlorine washing unit, is connected to the organic phase outlet of the back-extraction unit to wash CO3. 2- The unit is connected to the organic phase discharge end of the chlorine washing unit.

[0040] The advantages of this application, which differ from existing technical solutions, include:

[0041] 1. This application first uses sodium carbonate to wash the back-extracted organic phase with chlorine, and then uses sulfuric acid solution to remove CO3. 2- This solves the problem of emulsification in the extraction, washing, and back-extraction sections caused by using sodium carbonate solution for chlorine washing; at the same time, compared with directly using sulfuric acid solution for chlorine washing, the regeneration section in this application uses less sulfuric acid, which will not cause phase mixing during the chlorine washing process, and allows the entire scandium extraction system to maintain stable operation for a long time.

[0042] 2. This application uses high-concentration, low-flow-rate dilute sulfuric acid to wash CO3 from the dechlorinated organic phase. 2- High concentrations of dilute sulfuric acid affect CO3. 2- It has a good washing effect and will not cause emulsification in the extraction section. The low flow rate of dilute sulfuric acid can reduce the amount of sulfuric acid used and avoid sulfuric acid being carried in the organic extractant.

[0043] 3. This application uses dilute sulfuric acid to wash CO3. 2- The process involved saponifying the weakly alkaline long-chain primary amine extractant, which reduced the cost of adjusting the scandium-containing cobalt-nickel hydroxide solution.

[0044] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0045] To more clearly illustrate the technical solutions of this application, the accompanying drawings used in this application will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort.

[0046] Figure 1 This is a process flow diagram for this application. Detailed Implementation

[0047] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0049] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0050] A system for extracting scandium from a scandium-containing cobalt-nickel hydroxide solution includes an extraction unit, a washing unit, a back-extraction unit, a scandium extraction unit, and a regeneration unit connected sequentially along the material flow direction, each of which consists of several stages of reaction tanks.

[0051] The extraction unit comprises a two-stage extraction reaction tank, equipped with an organic extractant inlet, a cobalt-nickel solution outlet, and a scandium-containing organic phase outlet. The organic extractant and the scandium-containing cobalt-nickel hydroxide solution are mixed in the extraction unit. The scandium-containing cobalt-nickel hydroxide solution is then subjected to scandium extraction using the long-chain primary amine extractant N1923 to obtain both the cobalt-nickel solution and the scandium-containing organic phase. The two-stage scandium extraction process demonstrates good extraction efficiency.

[0052] The washing unit comprises four washing reaction tanks. The inlet of each washing reaction tank is connected to the outlet of the scandium-containing organic phase. Each washing reaction tank is equipped with a detergent inlet, a washing wastewater outlet, and a purified organic phase outlet. Dilute sulfuric acid is used as the detergent to wash the scandium-containing organic phase, removing impurities such as Co, Ni, Ti, and Cu, resulting in a purified organic phase and washing wastewater. The washing wastewater is discharged from the washing wastewater outlet.

[0053] The back-extraction unit comprises five back-extraction reaction tanks. The feed end of each back-extraction reaction tank is connected to the outlet of the purified organic phase, and the back-extraction reaction tank is equipped with an outlet for scandium-containing back-extraction solution and an outlet for the back-extracted organic phase. Hydrochloric acid is used to back-extract the purified organic phase, extracting the scandium element from the organic phase into the aqueous phase, yielding a scandium-containing back-extraction solution and the back-extracted organic phase.

[0054] The scandium extraction unit includes a sedimentation tank, a filtration mechanism, and a calcination furnace. In the sedimentation tank, oxalic acid is mixed with scandium-containing back-extraction solution to obtain scandium oxalate precipitate. The scandium oxalate precipitate is filtered and dried by the filtration mechanism, and then calcined in the calcination furnace to obtain scandium oxide.

[0055] The regeneration unit includes a 6-stage chlorine washing reaction tank and a 2-stage CO3 washing tank. 2- The reaction tank, specifically the chlorine washing reaction tank, is connected at its inlet to the outlet of the back-extracted organic phase. The chlorine washing reaction tank also includes an outlet for the dechlorinated organic phase and an outlet for chlorine-containing wastewater. Sodium carbonate solution is used to wash the back-extracted organic phase, producing CO3. 2- The polarity is greater than that of Cl.- It can remove Cl from the organic phase - The chlorine is displaced, resulting in a dechlorinated organic phase and chlorine-containing waste liquid, thus achieving chlorine washing. The chlorine-containing waste liquid is then discharged. The dechlorinated organic phase also contains a large amount of CO3. 2- Wash CO3 2- The feed end of the reaction tank is connected to the outlet of the dechlorinated organic phase to wash CO3. 2- The reaction tank also includes a regenerated organic extractant outlet and a regenerated wastewater outlet. Dilute sulfuric acid is used to remove CO3 from the dechlorinated organic phase. 2- The H+ and CO3 in dilute sulfuric acid are removed. 2- The reaction produces CO2, which is then released, avoiding the release of CO3. 2- The mixture carried to the subsequent extraction reaction tank causes phase mixing in the extraction section, ultimately resulting in regenerated organic extractant and regenerated waste liquid. The regenerated waste liquid is discharged, and the outlet of the regenerated organic extractant is connected to the inlet of the organic extractant in the extraction unit. The regenerated organic extractant is then returned to the extraction unit for recycling.

[0056] The following are some specific embodiments. All of these embodiments use the aforementioned system for extracting scandium from a scandium-containing cobalt-nickel hydroxide solution. It should be noted that the embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0057] I. Preparation Method

[0058] Example 1

[0059] A method for extracting scandium from a scandium-containing cobalt-nickel hydroxide solution, such as Figure 1 As shown, it includes the following steps:

[0060] (1) A two-stage extraction was performed on the scandium-containing cobalt-nickel hydroxide solution using an organic extractant. The flow rate of the scandium-containing cobalt-nickel hydroxide solution was 3.5 m. 3 The organic extractant, consisting of N1923 as a scandium extractant and n-dodecane as a diluent, has a concentration of 15% and a flow rate of 1.5 m³ / h. 3 / h, a cobalt-nickel solution and a scandium-containing organic phase are obtained; the scandium-containing cobalt-nickel hydroxide solution is sourced from the primary washing water of the iron-aluminum removal process in the laterite nickel ore treatment, and the nickel-cobalt solution after scandium removal is used for the next process to extract cobalt and nickel.

[0061] (2) A 2.25 mol / L dilute sulfuric acid was used as the detergent to perform a four-stage washing of the scandium-containing organic phase. The flow rate of the dilute sulfuric acid was 0.4 m³ / s. 3 The flow rate of the scandium-containing organic phase is 1.5 m³ / h.3 / h, yielding washing waste liquid and purified organic phase;

[0062] (3) The purified organic phase was back-extracted using 4 mol / L hydrochloric acid as the back-extraction agent at a flow rate of 0.2 m. 3 The flow rate of the purified organic phase is 1.5 m³ / h. 3 / h, to obtain scandium-containing back-extraction solution and back-extraction organic phase;

[0063] (4) Add oxalic acid precipitant to the scandium-containing back-extraction solution, and after precipitation, filtration and calcination, scandium oxide is obtained;

[0064] The back-extracted organic phase was washed with sodium carbonate solution to obtain a dechlorinated organic phase and chlorine-containing waste liquid; the concentration of the sodium carbonate solution was 0.4 mol / L, and the flow rate of the sodium carbonate solution was 0.6 m³ / L. 3 / h, the flow rate of the organic phase back-extraction is 1.5 m³ / h. 3 / h. Chlorine-containing wastewater is discharged, and the dechlorinated organic phase is used for washing with CO3. 2- deal with.

[0065] CO3 was washed off the dechlorinated organic phase using dilute sulfuric acid. 2- The resulting regenerated organic extractant and regenerated waste liquid were obtained; the concentration of the dilute sulfuric acid was 2.25 mol / L, and the flow rate of the dilute sulfuric acid was 0.35 m³ / L. 3 The flow rate of the dechlorinated organic phase is 1.5 m³ / h. 3 / h. The regenerated waste liquid is discharged, and the regenerated organic extractant is reused in step (1).

[0066] Example 2

[0067] A method for extracting scandium from a scandium-containing cobalt-nickel hydroxide solution includes the following steps:

[0068] (1) A two-stage extraction was performed on the scandium-containing cobalt-nickel hydroxide solution using an organic extractant. The organic extractant included N1923 as the scandium extractant and n-dodecane as the diluent. The concentration of the organic extractant was 30%, and the flow rate of the scandium-containing cobalt-nickel hydroxide solution was 5 m³ / s. 3 / h, the organic extractant flow rate is 1.2 m 3 / h, a cobalt-nickel solution and a scandium-containing organic phase were obtained;

[0069] (2) A 2.5 mol / L dilute sulfuric acid solution was used as the detergent to perform a four-stage washing process on the scandium-containing organic phase. The flow rate of the dilute sulfuric acid was 0.4 m³ / s. 3 The flow rate of the scandium-containing organic phase is 1.2 m³ / h. 3 / h, yielding washing waste liquid and purified organic phase;

[0070] (3) The purified organic phase was back-extracted using 4 mol / L hydrochloric acid as the back-extraction agent at a flow rate of 0.25 m³ / L. 3 The flow rate for purifying the organic phase is 1.2 m³ / h. 3 / h, to obtain scandium-containing back-extraction solution and back-extraction organic phase;

[0071] (4) Add oxalic acid precipitant to the scandium-containing back-extraction solution, and after precipitation, filtration and calcination, scandium oxide is obtained;

[0072] The back-extracted organic phase was washed with sodium carbonate solution to obtain a dechlorinated organic phase and chlorine-containing waste liquid; the concentration of the sodium carbonate solution was 0.4 mol / L, and the flow rate of the sodium carbonate solution was 0.7 m³ / L. 3 / h, the flow rate of the organic phase back-extraction is 1.2 m³ / h. 3 / h. Chlorine-containing wastewater is discharged, and the dechlorinated organic phase is used for washing with CO3. 2- deal with.

[0073] CO3 was washed off the dechlorinated organic phase using dilute sulfuric acid. 2- The resulting regenerated organic extractant and regenerated waste liquid were obtained; the concentration of the dilute sulfuric acid was 2.25 mol / L, and the flow rate of the dilute sulfuric acid was 0.35 m³ / L. 3 The flow rate of the dechlorinated organic phase is 1.2 m³ / h. 3 / h. The regenerated waste liquid is discharged, and the regenerated organic extractant is reused in step (1).

[0074] Example 3

[0075] A method for extracting scandium from a scandium-containing cobalt-nickel hydroxide solution includes the following steps:

[0076] (1) A two-stage extraction was performed on the scandium-containing cobalt-nickel hydroxide solution using an organic extractant. The organic extractant included N1923 as the scandium extractant and n-dodecane as the diluent. The concentration of the organic extractant was 20%, and the flow rate of the scandium-containing cobalt-nickel hydroxide solution was 5 m³ / s. 3 / h, the organic extractant flow rate is 1.3 m 3 / h, a cobalt-nickel solution and a scandium-containing organic phase were obtained;

[0077] (2) A 2.5 mol / L dilute sulfuric acid was used as the detergent to perform a four-stage washing of the scandium-containing organic phase. The flow rate of the dilute sulfuric acid was 0.35 m³ / L. 3 The flow rate of the scandium-containing organic phase is 1.3 m³ / h. 3 / h, yielding washing waste liquid and purified organic phase;

[0078] (3) The purified organic phase was back-extracted using 4 mol / L hydrochloric acid as the back-extraction agent at a flow rate of 0.25 m³ / L. 3 The flow rate of the purified organic phase is 1.3 m³ / h. 3 / h, to obtain scandium-containing back-extraction solution and back-extraction organic phase;

[0079] (4) Add oxalic acid precipitant to the scandium-containing back-extraction solution, and after precipitation, filtration and calcination, scandium oxide is obtained;

[0080] The back-extracted organic phase was washed with sodium carbonate solution to obtain a dechlorinated organic phase and chlorine-containing waste liquid; the concentration of the sodium carbonate solution was 0.4 mol / L, and the flow rate of the sodium carbonate solution was 0.7 m³ / L. 3 / h, the flow rate of the organic phase back-extraction is 1.3 m³ / h. 3 / h. Chlorine-containing wastewater is discharged, and the dechlorinated organic phase is used for washing with CO3. 2- deal with.

[0081] CO3 was washed off the dechlorinated organic phase using dilute sulfuric acid. 2- The resulting regenerated organic extractant and regenerated waste liquid were obtained; the concentration of the dilute sulfuric acid was 2.5 mol / L, and the flow rate of the dilute sulfuric acid was 0.3 m³ / L. 3 The flow rate of the dechlorinated organic phase is 1.2 m³ / h. 3 / h. The regenerated waste liquid is discharged, and the regenerated organic extractant is reused in step (1).

[0082] Comparative Example 1

[0083] A method for extracting scandium from a scandium-containing cobalt-nickel hydroxide solution includes the following steps:

[0084] (1) A two-stage extraction was performed on a scandium-containing cobalt-nickel hydroxide solution using the long-chain primary amine organic extractant N1923. The concentration of the organic extractant was 30%, and the flow rate of the scandium-containing cobalt-nickel hydroxide solution was 4 m³ / s. 3 / h, the organic extractant flow rate is 1.2 m 3 / h, a cobalt-nickel solution and a scandium-containing organic phase were obtained;

[0085] (2) A 1.5 mol / L dilute sulfuric acid solution was used as the detergent to perform a four-stage washing of the scandium-containing organic phase. The flow rate of the dilute sulfuric acid was 0.5 m³ / s. 3 The flow rate of the scandium-containing organic phase is 1.2 m³ / h. 3 / h, yielding washing waste liquid and purified organic phase;

[0086] (3) The purified organic phase was back-extracted using 5 mol / L hydrochloric acid as the back-extraction agent at a flow rate of 0.35 m³ / L. 3 The flow rate for purifying the organic phase is 1.2 m³ / h. 3 / h, to obtain scandium-containing back-extraction solution and back-extraction organic phase;

[0087] (4) Add oxalic acid precipitant to the scandium-containing back-extraction solution, and after precipitation, filtration and calcination, scandium oxide is obtained;

[0088] The back-extracted organic phase was washed with sodium carbonate solution to obtain a dechlorinated organic phase and chlorine-containing waste liquid; the concentration of the sodium carbonate solution was 0.4 mol / L, and the flow rate of the sodium carbonate solution was 0.7 m³ / L. 3 / h, the flow rate of the organic phase back-extraction is 1.2 m³ / h. 3 / h. Chlorine-containing wastewater is discharged, and the dechlorinated organic phase is used for washing with CO3. 2- deal with.

[0089] CO3 was washed off the dechlorinated organic phase using dilute sulfuric acid. 2- The resulting regenerated organic extractant and regenerated waste liquid were obtained; the concentration of the dilute sulfuric acid was 1.5 mol / L, and the flow rate of the dilute sulfuric acid was 0.4 m³ / L. 3 The flow rate of the dechlorinated organic phase is 1.2 m³ / h. 3 / h. The regenerated waste liquid is discharged, and the regenerated organic extractant is reused in step (1).

[0090] Comparative Example 2

[0091] A method for extracting scandium from a scandium-containing cobalt-nickel hydroxide solution includes the following steps:

[0092] (1) A two-stage extraction was performed on a scandium-containing cobalt-nickel hydroxide solution using the long-chain primary amine organic extractant N1923. The concentration of the organic extractant was 20%, and the flow rate of the scandium-containing cobalt-nickel hydroxide solution was 3.5 m. 3 / h, the organic extractant flow rate is 1.3 m 3 / h, a cobalt-nickel solution and a scandium-containing organic phase were obtained;

[0093] (2) A 1.5 mol / L dilute sulfuric acid solution was used as the detergent to perform a four-stage washing process on the scandium-containing organic phase. The flow rate of the dilute sulfuric acid was 0.4 m³ / s. 3 The flow rate of the scandium-containing organic phase is 1.3 m³ / h. 3 / h, yielding washing waste liquid and purified organic phase;

[0094] (3) The purified organic phase was back-extracted using 3.5 mol / L hydrochloric acid as the back-extraction agent at a flow rate of 0.25 m³ / L. 3 The flow rate of the purified organic phase is 1.3 m³ / h. 3 / h, to obtain scandium-containing back-extraction solution and back-extraction organic phase;

[0095] (4) Add oxalic acid precipitant to the scandium-containing back-extraction solution, and after precipitation, filtration and calcination, scandium oxide is obtained;

[0096] The back-extracted organic phase was washed with sodium carbonate solution to obtain a dechlorinated organic phase and chlorine-containing waste liquid; the concentration of the sodium carbonate solution was 0.4 mol / L, and the flow rate of the sodium carbonate solution was 0.6 m³ / L. 3 / h, the flow rate of the organic phase back-extraction is 1.3 m³ / h.3 / h. Chlorine-containing wastewater is discharged, and the dechlorinated organic phase is used for washing with CO3. 2- deal with.

[0097] CO3 was washed off the dechlorinated organic phase using dilute sulfuric acid. 2- The resulting regenerated organic extractant and regenerated waste liquid were obtained; the concentration of the dilute sulfuric acid was 1.5 mol / L, and the flow rate of the dilute sulfuric acid was 0.2 m³ / L. 3 The flow rate of the dechlorinated organic phase is 1.3 m³ / h. 3 / h. The regenerated waste liquid is discharged, and the regenerated organic extractant is reused in step (1).

[0098] Comparative Example 3

[0099] The difference between Comparative Example 3 and Comparative Example 1 is that only dilute sulfuric acid was used to wash the back-extracted organic phase with chlorine. The concentration of the dilute sulfuric acid was 3 mol / L, and the flow rate was 0.8 m³ / L. 3 / h, organic phase flow rate is 1.2 m³ / h. 3 / h.

[0100] Comparative Example 4

[0101] The difference between Comparative Example 4 and Comparative Example 1 is that only sodium carbonate was used to wash the back-extracted organic phase with chlorine. The concentration of the sodium carbonate solution was 1.2 mol / L, and the flow rate of the sodium carbonate solution was 1 m³ / L. 3 / h, the flow rate of the organic phase is 1.2 m³ / h. 3 / h.

[0102] II. Testing Methods

[0103] 1. Using ICP to analyze Sc 3+ Cl - The concentration was measured.

[0104] III. Analysis of Test Results for Each Embodiment and Comparative Example

[0105] For untreated scandium-containing cobalt-nickel hydroxide solution Sc 3+ Cl - Concentration and Cl in the regenerated organic extractant obtained in each example and comparative example - Concentration, Scandium-containing back-extraction solution of Sc 3+ The concentration and Sc enrichment factor were detected, and the detection data are shown in Table 1 below.

[0106] Table 1. Scandium Extraction System: Sc Sections 3+ Cl - Concentration test results

[0107]

[0108] In Examples 1 and 2, the back-extracted organic phase was washed with chlorine using 0.4 mol / L sodium carbonate and 2.25 mol / L dilute sulfuric acid. The resulting regenerated organic extractant contained Cl. - With a concentration below 100 mg / L, the chlorine washing effect was good, and no miscibility or emulsification was observed in either the extraction or back-extraction sections. In Example 3, 0.4 mol / L sodium carbonate and 2.5 mol / L dilute sulfuric acid were used to wash the back-extracted organic phase with chlorine, which improved the CO3 washing efficiency. 2- The concentration of dilute sulfuric acid was reduced, and the flow rate of dilute sulfuric acid was decreased. No miscibility or emulsification problems occurred in the extraction, washing, and back-extraction sections. - With a concentration below 100 mg / L, the chlorine washing effect is good, the scandium enrichment factor can reach 14~18 times, and the scandium extraction efficiency is high.

[0109] In Comparative Examples 1 and 2, 0.4 mol / L sodium carbonate and 1.5 mol / L dilute sulfuric acid were used to wash the back-extracted organic phase, resulting in good chlorine washing. However, due to the washing of CO3... 2- The low acidity of dilute sulfuric acid leads to CO3... 2- Poor washing results in bubble emulsification in the extraction and back-extraction sections, leading to a decrease in the Sc enrichment factor.

[0110] In Comparative Example 3, only dilute sulfuric acid was used for chlorine washing, which required a high concentration of dilute sulfuric acid. Prolonged operation would lead to emulsification in the extraction section, reducing the stability of the extraction system. In Comparative Example 4, only sodium carbonate was used for chlorine washing, which would lead to emulsification in the extraction, washing, and back-extraction sections, affecting the Sc extraction effect and reducing the Sc enrichment factor.

[0111] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A method for extracting scandium from a scandium-containing cobalt-nickel hydroxide solution, characterized in that, Includes the following steps: (1) The scandium-containing cobalt-nickel hydroxide solution was extracted with an organic extractant to obtain a cobalt-nickel solution and a scandium-containing organic phase; (2) The scandium-containing organic phase is washed with a detergent to obtain a purified organic phase; (3) The purified organic phase was back-extracted with hydrochloric acid to obtain a scandium-containing back-extraction solution and a back-extracted organic phase; (4) The scandium-containing back-extraction solution is subjected to scandium extraction treatment to obtain scandium oxide; The back-extracted organic phase is regenerated by sequentially using sodium carbonate and dilute sulfuric acid to obtain a regenerated organic extractant, which is then reused in step (1). The step of regenerating the back-extracted organic phase includes: (41) The back-extracted organic phase was washed with sodium carbonate solution to obtain a dechlorinated organic phase and chlorine-containing waste liquid; In step (41), the concentration of sodium carbonate solution is 0.4~1.5 mol / L, and the flow rate ratio of sodium carbonate solution to the back-extracted organic phase is (0.45~1.2):(1.2~1.5). (42) CO3 was washed off the dechlorinated organic phase using dilute sulfuric acid. 2- This yields a regenerated organic extractant and a regenerated waste liquid; In step (42), the concentration of dilute sulfuric acid is 2.25~2.5 mol / L, and the flow rate ratio of dilute sulfuric acid to dechlorinated organic phase is (0.3~0.35):(1.2~1.5).

2. The method for extracting scandium from a scandium-containing cobalt-nickel hydroxide solution according to claim 1, characterized in that, In step (1), sulfuric acid is used to adjust the pH to 0.3~1 during extraction.

3. The method for extracting scandium from a scandium-containing cobalt-nickel hydroxide solution according to claim 1, characterized in that, The scandium extraction process includes the following steps: adding oxalic acid to the scandium-containing back-extraction solution to obtain scandium oxalate precipitate, and filtering, washing, and calcining the scandium oxalate precipitate to obtain scandium oxide.

4. The method for extracting scandium from a scandium-containing cobalt-nickel hydroxide solution according to claim 1, characterized in that, The organic extractant includes a scandium extractant and a diluent, wherein the scandium extractant is a long-chain primary amine extractant, the diluent is n-dodecane, and the concentration of the organic extractant is 15% to 30%.

5. The method for extracting scandium from a scandium-containing cobalt-nickel hydroxide solution according to claim 1, characterized in that, In step (1), the flow rate ratio of the scandium-containing cobalt-nickel hydroxide solution to the organic extractant is (3.5~5.5):(1.2~1.5). In step (2), the ratio of detergent flow rate to scandium-containing organic phase flow rate is (0.3~0.5):(1.2~1.5); In step (3), the concentration of hydrochloric acid is 3.5~5 mol / L, and the ratio of hydrochloric acid to the flow rate of the purified organic phase is (0.2~0.25):(1.2~1.5).

6. The method for extracting scandium from a scandium-containing cobalt-nickel hydroxide solution according to claim 1, characterized in that, The detergent is dilute sulfuric acid with a concentration of 1.5~2.5 mol / L.

7. The method for extracting scandium from a scandium-containing cobalt-nickel hydroxide solution according to claim 6, characterized in that, H in the detergent + The concentration of H in the stripping agent is higher than that in the stripping agent. + concentration.

8. A system for extracting scandium from a solution containing scandium-containing cobalt-nickel hydroxide, characterized in that, include: An extraction unit is used to extract a solution containing scandium-containing cobalt-nickel hydroxide. A washing unit is connected to the discharge end of the extraction unit and is used to wash the scandium-containing organic phase obtained by the extraction unit. A back-extraction unit is connected to the discharge end of the washing unit and is used to back-extract the purified organic phase obtained from the washing unit. A scandium extraction unit is connected to the aqueous phase outlet of the back-extraction unit and is used to extract scandium from the scandium-containing back-extraction solution obtained from the back-extraction unit. The regeneration unit, connected to the organic phase outlet of the back-extraction unit, is used to sequentially wash the back-extracted organic phase obtained from the back-extraction unit with chlorine and CO3. 2- This yields a regenerated organic extractant; The organic phase outlet of the regeneration unit is connected to the organic extractant inlet of the extraction unit. The regeneration unit includes a chlorine washing unit and a CO3 washing unit arranged sequentially along the material flow direction. 2- The unit, wherein the chlorine washing unit is connected to the organic phase outlet end of the back-extraction unit, and the CO3 washing unit... 2- The unit is connected to the organic phase discharge end of the chlorine washing unit.

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