Method and system for extracting scandium from scandium-containing cobalt nickel hydroxide solution

Abstract

The invention provides a method and a system for extracting scandium from a scandium-containing cobalt-nickel hydroxide solution, and belongs to the technical field of heavy metal recovery, and the method comprises the following steps: extracting the scandium-containing cobalt-nickel hydroxide solution by adopting an organic extraction agent to obtain a scandium-containing organic phase; washing the scandium-containing organic phase to obtain a purified organic phase; hydrochloric acid is adopted for back extraction of the purified organic phase, and scandium-containing back extraction liquid and a back extraction organic phase are obtained; the scandium-containing strip liquor is subjected to scandium extraction treatment, and scandium oxide is obtained; the reverse extraction organic phase is regenerated through sodium carbonate and dilute sulphuric acid in sequence, a regenerated organic extraction agent is obtained, and the regenerated organic extraction agent is recycled. Sodium carbonate and a sulfuric acid solution are sequentially adopted for chlorine washing, and the problem of emulsification of an extraction section, a washing section and a reverse extraction section caused by chlorine washing with a sodium carbonate solution is solved; meanwhile, compared with a mode that a sulfuric acid solution is directly adopted for chlorine washing, little sulfuric acid is adopted in the regeneration section, and phase mixing in the chlorine washing process cannot be caused.

Description

Technical Field

[0001] The present invention relates to the technical field of heavy metal recovery, and in particular to a method and system for extracting scandium from a scandium-containing cobalt nickel hydroxide solution. Background Art

[0002] Amine extractants are a promising choice for the hydrometallurgical extraction of scandium. CN117701920A discloses a method for recovering scandium from laterite nickel ore using a secondary amine extractant. This extractant has high selectivity for scandium and can be stripped using weak acids and bases. Long-chain primary amine extractants are highly selective for scandium and can be stripped using weak acids and bases. They are also non-emulsifiable and are already suitable for large-scale scandium extraction and purification.

[0003] However, in the stripping process, stripping with a weak base will produce a three-phase problem, which will lead to difficulties in phase separation. During the production process of the production line, the long-chain primary amine extractant is stripped in a slightly acidic environment. The stripping effect of sulfuric acid solution is not good, while the stripping effect of hydrochloric acid is better and the stripping rate is high. However, when the long-chain primary amine extractant is stripped in an acidic system, it may form ion association complexes or amine salt complexes (such as R-NH3Cl) with chloride ions, causing chloride ions to be entrained into the organic phase. The harm of chloride ions to the extraction system: 1. Residual Cl in the organic phase - Or the complex will compete with the target metal ions for the active sites of the extractant, resulting in a decrease in the metal extraction rate in subsequent cycles; 2. The extraction capacity of the extractant depends on the system pH, Cl - Accumulation may change the local acidity and disrupt the extraction balance. Summary of the Invention

[0004] In view of the technical problems existing in the background technology, the present application provides a method and system for extracting scandium from a scandium-containing cobalt nickel hydroxide solution, aiming to solve the problem of using hydrochloric acid to strip the Cl in the organic phase. - Remaining technical issues.

[0005] In a first aspect, an embodiment of the present application provides a method for extracting scandium from a scandium-containing cobalt nickel hydroxide solution, comprising the following steps: (1) extracting the scandium-containing cobalt-nickel hydroxide solution with an organic extractant to obtain a cobalt-nickel solution and a scandium-containing organic phase; (2) washing the scandium-containing organic phase with a detergent to obtain a washing waste liquid and a purified organic phase; (3) using hydrochloric acid as a stripping agent to strip the purified organic phase to obtain a scandium-containing stripping solution and a stripping organic phase; (4) extracting scandium from the scandium-containing stripping solution to obtain scandium oxide; The stripping organic phase is regenerated in sequence with sodium carbonate and dilute sulfuric acid to obtain a regenerated organic extractant, which is then reused in step (1) to extract the scandium-containing cobalt nickel hydroxide solution.

[0006] In the technical solution of the embodiment of the present application, since a large amount of Cl - Directly reusing the stripping organic phase will result in a decrease in the metal extraction rate in subsequent cycles, so the stripping organic phase was regenerated.

[0007] Use sulfuric acid solution with higher concentration than hydrochloric acid to wash chlorine and remove Cl - In this case, the extraction system operates stably in the initial stage, but after a long period of operation, the acidity increases due to the continuous operation of the chlorine washing section, resulting in organic miscibility during the chlorine washing process, which causes some sulfuric acid to be entrained in the regenerated organic extractant, affecting the stability of the entire extraction system; and using a sulfuric acid solution with lower acidity to wash chlorine will result in insufficient chlorine washing.

[0008] Use sodium carbonate solution alone to wash chlorine and remove Cl - In the case of sulfuric acid system, compared with chlorine washing, CO3 2- The polarity of Cl - High, easier to strip Cl in the organic phase - However, long-term operation will lead to the accumulation of carbonate in the regenerated organic extractant, and the extraction of scandium-containing cobalt hydroxide nickel solution with the regenerated organic extractant is carried out under weak acidic conditions. + Will react with CO3 in the regenerated organic extractant 2- The reaction produces bubbles, which leads to emulsification of the extraction section, washing section and stripping section, affecting the entire extraction process.

[0009] This application first uses sodium carbonate to wash the chlorine from the stripping organic phase, and then uses sulfuric acid solution to remove CO3 2- , which solves the problem of emulsification in the extraction section, washing section and stripping section caused by using sodium carbonate solution to wash chlorine. At the same time, the solution uses less sulfuric acid solution, which will not cause miscibility during the chlorine washing process.

[0010] In some embodiments, the step of regenerating the stripped organic phase comprises: (41) using a sodium carbonate solution to wash the stripping organic phase with chlorine to obtain a dechlorinated organic phase and a chlorine-containing waste liquid; In the step (41), the concentration of the sodium carbonate solution is 0.4-1.5 mol / L, and the flow rate ratio of the sodium carbonate solution to the stripping organic phase is (0.45-1.2):(1.2-1.5); (42) Use dilute sulfuric acid to wash the dechlorinated organic phase with CO3 2- , obtaining a regenerated organic extractant and a regenerated waste liquid; In the step (42), the concentration of dilute sulfuric acid is 2.25-2.5 mol / L, and the flow rate ratio of the dilute sulfuric acid to the dechlorinated organic phase is (0.3-0.35):(1.2-1.5).

[0011] In the technical solution of the embodiment of the present application, the concentration of the sodium carbonate solution is reduced as much as possible under the conditions of chlorine washing, thereby reducing the chlorine washing section and the CO3 washing section. 2- The cost of auxiliary materials in this stage. Excessive CO3 2- It will be enriched in organic matter and increase the amount of CO3 washed 2- Difficulty.

[0012] This application uses high-concentration, low-flow dilute sulfuric acid to wash the dechlorinated organic phase with CO3 2- , high concentration of dilute sulfuric acid to CO3 2- It has a good washing effect and will not cause emulsification in the extraction section. The low flow of dilute sulfuric acid can reduce the amount of sulfuric acid used and avoid the entrainment of sulfuric acid in the organic extractant.

[0013] In some embodiments, during the extraction in step (1), sulfuric acid is used to adjust the pH to 0.3-1.

[0014] In some embodiments, the scandium extraction process comprises the following steps: adding oxalic acid to a scandium-containing stripping solution to obtain a scandium oxalate precipitate; filtering, washing, and calcining the scandium oxalate precipitate to obtain scandium oxide.

[0015] In some embodiments, the organic extractant includes a scandium extractant and a diluent, 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%.

[0016] 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); In step (2), the ratio of the flow rate of the detergent to the scandium-containing organic phase is (0.3-0.5):(1.2-1.5); In the 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).

[0017] In the technical solution of the embodiment of the present application, the washing section uses high-concentration, low-flow sulfuric acid for washing, which can solve the emulsification problem of the washing section; the stripping section can avoid emulsification in the stripping section by increasing the flow rate of the stripping agent hydrochloric acid to ensure that the volume ratio O / A of the organic phase (O) and the aqueous phase (A) in the stripping section is less than 6.5.

[0018] In some embodiments, the detergent is dilute sulfuric acid with a concentration of 1.5-2.5 mol / L.

[0019] In some embodiments, the H in the detergent + The concentration is higher than H in the stripping agent + concentration.

[0020] In the technical solution of the embodiment of the present application, a relatively high concentration of sulfuric acid is used in the detergent to prevent the generation of carbon dioxide in the stripping stage from producing bubbles and emulsification.

[0021] In a second aspect, an embodiment of the present application provides a system for extracting scandium from a scandium-containing cobalt nickel hydroxide solution, comprising: An extraction unit, used for extracting the scandium-containing cobalt nickel hydroxide solution; A washing unit connected to the discharge end of the extraction unit and used to wash the scandium-containing organic phase extracted by the extraction unit; a stripping unit connected to the discharge end of the washing unit and used to strip the purified organic phase obtained from the washing unit; A scandium extraction unit is connected to the water outlet of the stripping unit and is used to extract scandium from the scandium-containing stripping solution obtained from the stripping unit; The regeneration unit is connected to the organic phase discharge end of the stripping unit and is used to sequentially wash chlorine and CO3 from the stripping organic phase obtained in the stripping unit. 2- , obtaining a regenerated organic extractant; The organic phase discharge end of the regeneration unit is connected to the organic extractant feed end of the extraction unit.

[0022] In the technical solution of the embodiment of the present application, the regeneration unit includes a chlorine washing unit and a CO3 washing unit arranged in sequence along the material flow direction. 2- Unit, the chlorine washing unit is connected to the organic phase discharge end of the stripping unit to wash CO3 2- The unit is connected to the organic phase discharge end of the chlorine washing unit.

[0023] Different from the existing technical solutions, the beneficial effects of this application include: 1. This application first uses sodium carbonate to wash the chlorine from the stripping organic phase, and then uses sulfuric acid solution to remove CO3 2- , which solves the problem of emulsification in the extraction section, washing section and stripping section caused by using sodium carbonate solution to wash chlorine; at the same time, compared with directly using sulfuric acid solution to wash chlorine, the regeneration section in this application uses less sulfuric acid, which will not cause mixed phases during the chlorine washing process, allowing the entire scandium extraction system to maintain long-term stable operation.

[0024] 2. This application uses high-concentration, low-flow dilute sulfuric acid to wash the dechlorinated organic phase with CO3 2- , high concentration of dilute sulfuric acid to CO3 2-It has a good washing effect and will not cause emulsification in the extraction section. The low flow of dilute sulfuric acid can reduce the amount of sulfuric acid used and avoid the entrainment of sulfuric acid in the organic extractant.

[0025] 3. This application uses dilute sulfuric acid to wash CO3 2- The weakly alkaline long-chain primary amine extractant was saponified, which reduced the cost of adjusting the scandium-containing cobalt nickel hydroxide solution.

[0026] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] To more clearly illustrate the technical solution of this application, the following is a brief introduction to the drawings used in this application. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be derived from these drawings without inventive effort.

[0028] Figure 1 This is the process flow chart for this application. DETAILED DESCRIPTION

[0029] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0031] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0032] A system for extracting scandium from a scandium-containing cobalt nickel hydroxide solution comprises an extraction unit, a washing unit, a back-extraction unit, a scandium extraction unit and a regeneration unit which are sequentially connected along the material flow direction. Each of the above units is composed of several stages of reaction tanks.

[0033] The extraction unit includes a two-stage extraction reaction tank equipped with an organic extractant feed, 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 a cobalt-nickel solution and a scandium-containing organic phase. This two-stage scandium extraction process provides excellent extraction results.

[0034] The washing unit comprises four washing reaction tanks, the feed end of which is connected to the outlet of the scandium-containing organic phase. The washing reaction tanks are also equipped with a detergent feed, a washing waste liquid outlet, and a purified organic phase outlet. Dilute sulfuric acid is used as a detergent to wash the scandium-containing organic phase, removing impurities such as Co, Ni, Ti, and Cu. This produces a purified organic phase and a washing waste liquid, which is discharged through the washing waste liquid outlet.

[0035] The stripping unit includes a five-stage stripping reaction tank. The feed end of the stripping reaction tank is connected to the outlet of the purified organic phase. The stripping reaction tank is also equipped with an outlet for the scandium-containing stripping solution and an outlet for the stripped organic phase. The purified organic phase is stripped with hydrochloric acid to strip the scandium from the organic phase into the aqueous phase, producing a scandium-containing stripping solution and a stripped organic phase.

[0036] The scandium extraction unit includes a sedimentation tank, a filtering mechanism and a calcining furnace. Oxalic acid and scandium-containing stripping liquid are mixed in the sedimentation tank to obtain scandium oxalate precipitate. The scandium oxalate precipitate is filtered and dried using the filtering mechanism, and then calcined in a calcining furnace to obtain scandium oxide.

[0037] The regeneration unit includes a 6-stage chlorine washing reaction tank and a 2-stage CO3 washing tank. 2- The feed end of the chlorine-washing reaction tank is connected to the outlet of the stripping organic phase, and the chlorine-washing reaction tank also includes a dechlorinated organic phase outlet and a chlorine-containing waste liquid outlet. Sodium carbonate solution is used to wash the stripping organic phase with chlorine, CO3 2- The polarity is greater than Cl - , the Cl in the organic phase can be - The dechlorinated organic phase and chlorine-containing waste liquid are replaced to obtain dechlorinated organic phase and chlorine-containing waste liquid, so as to achieve chlorine washing and discharge of chlorine-containing waste liquid. The dechlorinated organic phase also contains a large amount of CO3 2- , washing CO3 2- The feed end of the reaction tank is connected to the outlet of the dechlorinated organic phase, and the CO3 2- The reaction tank also includes a regeneration organic extractant outlet and a regeneration waste liquid outlet. Dilute sulfuric acid is used to remove CO3 in the dechlorinated organic phase.2- To remove H+ and CO3 in dilute sulfuric acid 2- The reaction generates CO2 and discharges it to avoid CO3 2- The mixed phase of the extraction section caused by being carried to the subsequent extraction reaction tank finally obtains the regenerated organic extractant and the regenerated waste liquid. The regenerated waste liquid is discharged, and the outlet of the regenerated organic extractant is connected to the organic extractant feed port of the extraction unit. The regenerated organic extractant is refluxed to the extraction unit for recycling.

[0038] Some specific examples are listed below. The following examples all use the above-mentioned system for extracting scandium from a scandium-containing cobalt nickel hydroxide solution to extract scandium. It should be noted that the examples described below are exemplary and are only used to explain this application and should not be understood as limiting this application. If no specific techniques or conditions are specified in the examples, the techniques or conditions described in the literature in this field or the product instructions are used. The reagents or instruments used without indicating the manufacturer are all conventional products that can be purchased commercially.

[0039] 1. Preparation method Example 1 A method for extracting scandium from a scandium-containing cobalt nickel hydroxide solution, such as Figure 1 As shown, the following steps are included: (1) The scandium-containing cobalt-nickel hydroxide solution was subjected to a two-stage extraction using an organic extractant. The flow rate of the scandium-containing cobalt-nickel hydroxide solution was 3.5 m 3 / h, the organic extractant includes N1923 as the scandium extractant, n-dodecane as the diluent, the organic extractant concentration is 15%, and the organic extractant flow rate is 1.5 m 3 / h, to obtain a cobalt-nickel solution and a scandium-containing organic phase; the scandium-containing cobalt-nickel hydroxide solution comes from a slag wash water in the iron and aluminum removal process during laterite nickel ore processing, and the nickel-cobalt solution after scandium removal is used for the next step of cobalt and nickel extraction.

[0040] (2) Using 2.25 mol / L dilute sulfuric acid as a detergent, the organic phase containing scandium was washed in four stages, with a dilute sulfuric acid flow rate of 0.4 m 3 / h, the flow rate of the organic phase containing scandium is 1.5 m 3 / h, to obtain washing waste liquid and purified organic phase; (3) 4 mol / L hydrochloric acid was used as the stripping agent to strip the purified organic phase. The hydrochloric acid flow rate was 0.2 m 3 / h, the flow rate of the purified organic phase is 1.5 m 3 / h, to obtain a stripping solution containing scandium and a stripping organic phase; (4) adding oxalic acid precipitant to the scandium-containing stripping solution, and obtaining scandium oxide after precipitation, filtration, and calcination; The stripping organic phase was dechlorinated with sodium carbonate solution to obtain a dechlorinated organic phase and a 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 m 3 / h, the flow rate of the stripping organic phase is 1.5 m 3 / h. Chlorine-containing waste liquid is discharged, and the dechlorinated organic phase is used to wash CO3 2- deal with.

[0041] Use dilute sulfuric acid to wash the dechlorinated organic phase with CO3 2- , to obtain a regenerated organic extractant and a regenerated waste liquid; the concentration of dilute sulfuric acid is 2.25 mol / L, and the dilute sulfuric acid flow rate is 0.35 m 3 / h, the flow rate of the dechlorinated organic phase is 1.5 m 3 / h. The regenerated waste liquid is discharged, and the regenerated organic extractant is reused in step (1).

[0042] Example 2 A method for extracting scandium from a scandium-containing cobalt nickel hydroxide solution comprises the following steps: (1) The scandium-containing cobalt-nickel hydroxide solution was subjected to a two-stage extraction using an organic extractant, wherein the organic extractant included N1923 as a scandium extractant, n-dodecane as a diluent, the organic extractant concentration was 30%, and the flow rate of the scandium-containing cobalt-nickel hydroxide solution was 5m 3 / h, the organic extractant flow rate is 1.2 m 3 / h, to obtain a cobalt-nickel solution and a scandium-containing organic phase; (2) Using 2.5 mol / L dilute sulfuric acid as a detergent, the organic phase containing scandium was washed in four stages, with a dilute sulfuric acid flow rate of 0.4 m 3 / h, the flow rate of the organic phase containing scandium is 1.2 m 3 / h, to obtain washing waste liquid and purified organic phase; (3) 4 mol / L hydrochloric acid was used as the stripping agent to strip the purified organic phase. The hydrochloric acid flow rate was 0.25 m 3 / h, the flow rate of the purified organic phase is 1.2 m 3 / h, to obtain a stripping solution containing scandium and a stripping organic phase; (4) adding oxalic acid precipitant to the scandium-containing stripping solution, and obtaining scandium oxide after precipitation, filtration, and calcination; The stripping organic phase was dechlorinated with sodium carbonate solution to obtain a dechlorinated organic phase and a 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 m 3 / h, the flow rate of the stripping organic phase is 1.2 m 3 / h. Chlorine-containing waste liquid is discharged, and the dechlorinated organic phase is used to wash CO3 2- deal with.

[0043] Use dilute sulfuric acid to wash the dechlorinated organic phase with CO3 2- , to obtain a regenerated organic extractant and a regenerated waste liquid; the concentration of dilute sulfuric acid is 2.25 mol / L, and the dilute sulfuric acid flow rate is 0.35 m 3 / h, the flow rate of the dechlorinated organic phase is 1.2 m 3 / h. The regenerated waste liquid is discharged, and the regenerated organic extractant is reused in step (1).

[0044] Example 3 A method for extracting scandium from a scandium-containing cobalt nickel hydroxide solution comprises the following steps: (1) The scandium-containing cobalt-nickel hydroxide solution was subjected to a two-stage extraction using an organic extractant, wherein the organic extractant included N1923 as a scandium extractant, n-dodecane as a diluent, the organic extractant concentration was 20%, and the flow rate of the scandium-containing cobalt-nickel hydroxide solution was 5m 3 / h, the organic extractant flow rate is 1.3 m 3 / h, to obtain a cobalt-nickel solution and a scandium-containing organic phase; (2) Using 2.5 mol / L dilute sulfuric acid as a detergent, the organic phase containing scandium was washed in four stages, with a dilute sulfuric acid flow rate of 0.35 m 3 / h, the flow rate of the organic phase containing scandium is 1.3 m 3 / h, to obtain washing waste liquid and purified organic phase; (3) 4 mol / L hydrochloric acid was used as the stripping agent to strip the purified organic phase. The hydrochloric acid flow rate was 0.25 m 3 / h, the flow rate of the purified organic phase is 1.3 m 3 / h, to obtain a stripping solution containing scandium and a stripping organic phase; (4) adding oxalic acid precipitant to the scandium-containing stripping solution, and obtaining scandium oxide after precipitation, filtration, and calcination; The stripping organic phase was dechlorinated with sodium carbonate solution to obtain a dechlorinated organic phase and a 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 m 3 / h, the flow rate of the stripping organic phase is 1.3 m 3 / h. Chlorine-containing waste liquid is discharged, and the dechlorinated organic phase is used to wash CO3 2- deal with.

[0045] Use dilute sulfuric acid to wash the dechlorinated organic phase with CO3 2- , to obtain a regenerated organic extractant and a regenerated waste liquid; the concentration of dilute sulfuric acid is 2.5 mol / L, and the dilute sulfuric acid flow rate is 0.3 m 3 / h, the flow rate of the dechlorinated organic phase is 1.2 m 3 / h. The regenerated waste liquid is discharged, and the regenerated organic extractant is reused in step (1).

[0046] Comparative Example 1 A method for extracting scandium from a scandium-containing cobalt nickel hydroxide solution comprises the following steps: (1) The scandium-containing cobalt-nickel hydroxide solution was subjected to a two-stage extraction using a long-chain primary amine organic extractant N1923. The organic extractant concentration was 30%, and the flow rate of the scandium-containing cobalt-nickel hydroxide solution was 4 m 3 / h, the organic extractant flow rate is 1.2 m 3 / h, to obtain a cobalt-nickel solution and a scandium-containing organic phase; (2) Using 1.5 mol / L dilute sulfuric acid as a detergent, the organic phase containing scandium was washed in four stages, with a dilute sulfuric acid flow rate of 0.5 m 3 / h, the flow rate of the organic phase containing scandium is 1.2 m 3 / h, to obtain washing waste liquid and purified organic phase; (3) 5 mol / L hydrochloric acid was used as the stripping agent to strip the purified organic phase. The hydrochloric acid flow rate was 0.35 m 3 / h, the flow rate of the purified organic phase is 1.2 m 3 / h, to obtain a stripping solution containing scandium and a stripping organic phase; (4) adding oxalic acid precipitant to the scandium-containing stripping solution, and obtaining scandium oxide after precipitation, filtration, and calcination; The stripping organic phase was dechlorinated with sodium carbonate solution to obtain a dechlorinated organic phase and a 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 m 3 / h, the flow rate of the stripping organic phase is 1.2 m 3 / h. Chlorine-containing waste liquid is discharged, and the dechlorinated organic phase is used to wash CO3 2- deal with.

[0047] Use dilute sulfuric acid to wash the dechlorinated organic phase with CO3 2- , to obtain a regenerated organic extractant and a regenerated waste liquid; the concentration of dilute sulfuric acid is 1.5 mol / L, and the dilute sulfuric acid flow rate is 0.4 m 3 / h, the flow rate of the dechlorinated organic phase is 1.2 m 3 / h. The regenerated waste liquid is discharged, and the regenerated organic extractant is reused in step (1).

[0048] Comparative Example 2 A method for extracting scandium from a scandium-containing cobalt nickel hydroxide solution comprises the following steps: (1) The scandium-containing cobalt-nickel hydroxide solution was subjected to a two-stage extraction using a long-chain primary amine organic extractant N1923. The organic extractant concentration 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 m3 / h, to obtain a cobalt-nickel solution and a scandium-containing organic phase; (2) Using 1.5 mol / L dilute sulfuric acid as a detergent, the organic phase containing scandium was washed in four stages, with a dilute sulfuric acid flow rate of 0.4 m 3 / h, the flow rate of the organic phase containing scandium is 1.3 m 3 / h, to obtain washing waste liquid and purified organic phase; (3) 3.5 mol / L hydrochloric acid was used as the stripping agent to strip the purified organic phase. The hydrochloric acid flow rate was 0.25 m 3 / h, the flow rate of the purified organic phase is 1.3 m 3 / h, to obtain a stripping solution containing scandium and a stripping organic phase; (4) adding oxalic acid precipitant to the scandium-containing stripping solution, and obtaining scandium oxide after precipitation, filtration, and calcination; The stripping organic phase was dechlorinated with sodium carbonate solution to obtain a dechlorinated organic phase and a 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 m 3 / h, the flow rate of the stripping organic phase is 1.3 m 3 / h. Chlorine-containing waste liquid is discharged, and the dechlorinated organic phase is used to wash CO3 2- deal with.

[0049] Use dilute sulfuric acid to wash the dechlorinated organic phase with CO3 2- , to obtain a regenerated organic extractant and a regenerated waste liquid; the concentration of dilute sulfuric acid is 1.5 mol / L, and the dilute sulfuric acid flow rate is 0.2 m 3 / h, the flow rate of the dechlorinated organic phase is 1.3 m 3 / h. The regenerated waste liquid is discharged, and the regenerated organic extractant is reused in step (1).

[0050] Comparative Example 3 The difference between Comparative Example 3 and Comparative Example 1 is that only dilute sulfuric acid is used to wash the chlorine from the stripping organic phase. The concentration of dilute sulfuric acid is 3 mol / L and the flow rate is 0.8 m 3 / h, the organic phase flow rate is 1.2 m 3 / h.

[0051] Comparative Example 4 The difference between Comparative Example 4 and Comparative Example 1 is that only sodium carbonate is used to wash the chlorine from the stripping organic phase, the concentration of the sodium carbonate solution is 1.2 mol / L, and the flow rate of the sodium carbonate solution is 1 m 3 / h, the flow rate of the organic phase is 1.2 m 3 / h.

[0052] 2. Test Method 1. Use ICP to detect Sc 3+、Cl - The concentration was tested.

[0053] 3. Analysis of test results of various embodiments and comparative examples Untreated scandium-containing cobalt nickel hydroxide solution Sc 3+ 、Cl - Concentration and Cl in the regenerated organic extractant obtained in each embodiment and comparative example - concentration, Sc containing stripping solution 3+ The concentration and Sc enrichment multiple were tested, and the test data were shown in Table 1 below.

[0054] Table 1 Sc in each section of the scandium extraction system 3+ 、Cl - Concentration test results

[0055] In Examples 1 and 2, 0.4 mol / L sodium carbonate and 2.25 mol / L dilute sulfuric acid were used to wash chlorine from the stripping organic phase, and the Cl content in the obtained regenerated organic extractant was - The chlorine removal effect is good, and there is no mixed phase or emulsification in the extraction section and the stripping section. In Example 3, 0.4 mol / L sodium carbonate and 2.5 mol / L dilute sulfuric acid are used to remove chlorine from the stripping organic phase, which improves the CO3 removal efficiency. 2- The concentration of dilute sulfuric acid in the extraction section was reduced, and the flow rate of dilute sulfuric acid was reduced. There was no miscible phase or emulsification problem in the extraction section, washing section and stripping section. - The concentration of scandium is below 100 mg / L, the chlorine washing effect is good, the enrichment multiple of scandium can reach 14 to 18 times, and the scandium extraction efficiency is relatively high.

[0056] 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 stripping organic phase for chlorine. The chlorine washing effect was good, but due to the washing of CO3 2- The acidity of dilute sulfuric acid is low, resulting in CO3 2- The washing effect is poor, resulting in bubble emulsification in the extraction and stripping sections, and a decrease in the Sc enrichment multiple.

[0057] In Comparative Example 3, only dilute sulfuric acid was used for chlorine scrubbing, which required the use of a relatively high concentration of dilute sulfuric acid. Long-term operation would cause emulsification in the extraction section, thereby reducing the stability of the extraction system. In Comparative Example 4, only sodium carbonate was used for chlorine scrubbing, which would cause emulsification in the extraction section, the washing section, and the stripping section, thereby affecting the Sc extraction effect and reducing the Sc enrichment multiple.

[0058] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and any embodiments having substantially the same structure and effect as the technical concept within the scope of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the present application, any other embodiments that can be conceived by those skilled in the art and that combine some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A method for extracting scandium from a scandium-containing cobalt nickel hydroxide solution, characterized in that: The process includes the following steps: (1) extracting the scandium-containing cobalt-nickel hydroxide solution with an organic extractant to obtain a cobalt-nickel solution and a scandium-containing organic phase; (2) washing the scandium-containing organic phase with a detergent to obtain a purified organic phase; (3) stripping the purified organic phase with hydrochloric acid to obtain a stripping solution containing scandium and a stripping organic phase; (4) extracting scandium from the scandium-containing stripping solution to obtain scandium oxide; The stripping organic phase is regenerated in sequence using sodium carbonate and dilute sulfuric acid to obtain a regenerated organic extractant, which is then reused in step (1).

2. The method for extracting scandium from a scandium-containing cobalt-nickel hydroxide solution according to claim 1, wherein The step of regenerating the stripping organic phase comprises: (41) using a sodium carbonate solution to wash the stripping organic phase with chlorine to obtain a dechlorinated organic phase and a chlorine-containing waste liquid; In the step (41), the concentration of the sodium carbonate solution is 0.4-1.5 mol / L, and the flow rate ratio of the sodium carbonate solution to the stripping organic phase is (0.45-1.2):(1.2-1.5); (42) Use dilute sulfuric acid to wash the dechlorinated organic phase with CO3 2- , obtaining a regenerated organic extractant and a regenerated waste liquid; In the step (42), the concentration of dilute sulfuric acid is 2.25-2.5 mol / L, and the flow rate ratio of the dilute sulfuric acid to the dechlorinated organic phase is (0.3-0.35):(1.2-1.5).

3. The method for extracting scandium from a scandium-containing cobalt-nickel hydroxide solution according to claim 1, wherein: During the extraction in step (1), sulfuric acid is used to adjust the pH to 0.3-1.

4. The method for extracting scandium from a scandium-containing cobalt-nickel hydroxide solution according to claim 2, wherein: The scandium extraction process comprises the following steps: adding oxalic acid to the scandium-containing stripping solution to obtain a scandium oxalate precipitate; filtering, washing, and calcining the scandium oxalate precipitate to obtain scandium oxide.

5. The method for extracting scandium from a scandium-containing cobalt-nickel hydroxide solution according to claim 1, wherein: The organic extractant includes a scandium extractant and a diluent. 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%.

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

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

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

9. A system for extracting scandium from a scandium-containing cobalt nickel hydroxide solution, characterized in that: include: An extraction unit, used for extracting the scandium-containing cobalt nickel hydroxide solution; A washing unit connected to the discharge end of the extraction unit and used to wash the scandium-containing organic phase extracted by the extraction unit; a stripping unit connected to the discharge end of the washing unit and used to strip the purified organic phase obtained by the washing unit; A scandium extraction unit connected to the water outlet of the stripping unit and used to extract scandium from the scandium-containing stripping solution obtained from the stripping unit; The regeneration unit is connected to the organic phase discharge end of the stripping unit and is used to sequentially wash chlorine and CO3 from the stripping organic phase obtained in the stripping unit. 2- , obtaining a regenerated organic extractant; The organic phase discharge end of the regeneration unit is connected to the organic extractant feed end of the extraction unit.

10. The system for extracting scandium from a scandium-containing cobalt-nickel hydroxide solution according to claim 9, characterized in that: The regeneration unit includes a chlorine washing unit and a CO3 washing unit arranged in sequence along the material flow direction. 2- Unit, the chlorine washing unit is connected to the organic phase discharge end of the stripping unit, the CO3 washing 2- The unit is connected to the organic phase discharge end of the chlorine washing unit.

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