A method for preparing a battery-grade vanadyl sulfate electrolyte solution by using vanadium leaching solution

Abstract

The application discloses a method for preparing battery-grade vanadyl sulfate electrolyte by using vanadium leaching solution, and comprises the following steps: S1, using vanadium leaching solution with a vanadium ion concentration of 1.0-20 g / L as a raw solution, using sulfurous acid solution or saturated SO2 solution as a desorption solution, carrying out anion resin adsorption-desorption treatment and reduction treatment, and obtaining vanadyl sulfate solution with a vanadium ion concentration of 20-40 g / L; sequentially carrying out extraction and reverse extraction on the vanadyl sulfate solution with a vanadium ion concentration of 20-40 g / L, and obtaining vanadyl sulfate electrolyte with a vanadium ion concentration of 80-160 g / L; and S3, filtering the vanadyl sulfate electrolyte with a vanadium ion concentration of 80-160 g / L after adsorption by an adsorbent, and obtaining battery-grade vanadyl sulfate electrolyte. The application can simultaneously / synchronously realize removal of impurities in the vanadium leaching solution, efficient reduction conversion and enrichment and purification of vanadium ions, and achieves the technical effects of improving product quality, shortening a process flow, improving production efficiency and reducing production cost.

Description

Technical Field

[0001] The invention relates to the technical fields of metallurgical engineering and chemical engineering, and in particular to a method for preparing a battery-grade vanadyl sulfate electrolyte by utilizing a vanadium leaching solution. Background Art

[0002] Vanadium battery electrolytes generally use high-purity VOSO4 (vanadium oxysulfate) as their core raw material. After a pre-electrolysis treatment, cathode and anode electrolytes with the desired valence states can be obtained. Currently, the main method for large-scale production of vanadyl sulfate electrolytes is chemical reduction, using a reducing agent to dissolve and reduce high-purity V2O5 to VOSO4. However, the high cost of high-purity V2O5 directly leads to high production costs for the electrolyte, thus hindering the promotion and application of vanadium batteries. In addition, some studies have attempted to prepare electrolytes with different valence states by electrolyzing a suspension of V2O5 and sulfuric acid. While this method effectively controls the introduction of impurities, its production efficiency is low and its energy consumption is high, making it difficult to meet the needs of large-scale production. Currently, its application is limited to small-scale laboratory applications. To overcome the technical bottleneck of the high cost of vanadium battery electrolytes, finding low-cost raw materials and developing stable, mature, and scalable production processes and technologies are crucial. Broadening the sources of low-cost vanadium electrolyte raw materials can be traced back to the upstream of the vanadium industry chain. For example, vanadium extraction leachate from vanadium-containing minerals such as stone coal, vanadium slag, vanadium-titanium magnetite, and waste vanadium-based catalysts can be directly used to enrich and reduce VOSO4 vanadium battery electrolyte. This requires the enrichment and reduction of vanadium ions in the leachate and the removal of impurity ions.

[0003] Current processes and technologies generally have problems such as long process flow, low efficiency, and low vanadium ion recovery rate. Some processes or technologies use vanadium leaching solution to enrich and reduce vanadium ions after impurity removal and purification. However, the mineral composition of vanadium extraction raw materials is relatively complex. In addition to the dissolution of pentavalent vanadate anions during the leaching process, it also contains a large amount of SiO3. 2- ,AlO2 - ,Mg 2+ ,Fe 3+ ,Ca 2+ ,Mg 2+ The impurity ions such as ions are dissolved into the vanadium leaching solution, and the process of removing impurities from the vanadium leaching solution by chemical reaction is long and the steps are relatively complicated.

[0004] Some processes and technologies directly use extraction or ion exchange method to enrich vanadium ions and remove impurity ions. However, the concentration of vanadium ions in the vanadium-containing leaching solution is low. In order to make the concentration of vanadium ions in the solution meet the requirements of vanadium battery electrolyte, it is usually necessary to enrich the concentration of vanadium ions by 20-70 times. In order to meet the requirements of vanadium battery electrolyte on the concentration of vanadium ions, the existing technology has to reduce the phase ratio of extraction or greatly reduce the amount of ion exchange resin and desorption solution in order to enrich the concentration of vanadium ions, which will result in a large decrease in the recovery rate and enrichment efficiency of vanadium. Therefore, the existing extraction method or ion exchange method is difficult to ensure the concentration and recovery rate of vanadium ions at the same time. In addition, the multiple / multi-stage extraction operation used in the existing process will cause a certain amount of organic phase to remain in the electrolyte product, which will damage the proton exchange membrane during the operation of the battery and seriously shorten the service life of the battery.

[0005] Some existing technologies do not use a single ion exchange method or extraction method to prepare vanadium electrolyte. They combine ion exchange method and extraction method, purify the leaching solution by ion exchange, and then concentrate by solvent extraction and back extraction. The applicant finds that in such technical solutions, the ion exchange purification step is carried out in steps. First, the wet resin is used to adsorb the leaching solution. After the resin is saturated, sulfuric acid (salt) solution is used for desorption. Although this kind of technical solution can also purify the leaching solution, the desorption principle is to use the concentration difference of SO4 2- to cause VO3 - , Cl - , SiO3 2- and other anions to desorb from the resin. The following technical problems exist: 1. The obtained solution still inevitably contains a certain amount of impurity anions; 2. The valence of vanadium ions is still +5, and subsequent reduction treatment is still needed, which leads to a complex process and a long processing flow; 3. A large amount of desorption solution is needed; 4. For leaching solutions with more impurity ions, the leaching solution still needs to be purified before ion exchange purification, which undoubtedly limits the types of leaching solutions, increases the production time and cost, and reduces the production efficiency.

[0006] Therefore, the existing processes and technologies generally have problems of long process flow, low efficiency, and low recovery rate of vanadium ions. SUMMARY

[0007] The technical problem to be solved by the present application is to overcome the shortcomings of the prior art and provide a method for preparing battery-grade vanadyl sulfate electrolyte from vanadium leaching stock solution, which can simultaneously / synchronously realize the removal of impurities in the vanadium leaching solution, efficient reduction conversion and enrichment purification of vanadium ions, and achieve the technical effects of improving product quality, shortening process flow, improving production efficiency and reducing production cost.

[0008] To solve the above technical problems, the following technical solutions are adopted in the present application:

[0009] A method for preparing a battery-grade vanadyl sulfate electrolyte using a vanadium leachate comprises the following steps:

[0010] S1. Using a vanadium ion concentration of 1.0 to 20 g / L vanadium leachate as a stock solution and a sulfurous acid solution or a saturated SO2 solution as a desorption solution, the stock solution is allowed to flow from one end of an anion exchange resin to the other end for adsorption treatment, and the desorption solution is allowed to flow from the ion exchange resin in the opposite direction for elution reduction desorption treatment to obtain a vanadyl sulfate solution with a vanadium ion concentration of 20 to 40 g / L;

[0011] S2, extracting and stripping a vanadyl sulfate solution having a vanadium ion concentration of 20 to 40 g / L to obtain a vanadyl sulfate electrolyte having a vanadium ion concentration of 80 to 160 g / L; extracting with an organic extraction phase, wherein the extractant of the organic extraction phase is one or more of alkylphosphonic acid, alkylphosphoric acid, and alkylphosphinic acid; stripping with a stripping agent, wherein the stripping agent is a sulfuric acid solution having a concentration of 1.0 to 2.0 mol / L;

[0012] S3. Adsorbing the vanadyl sulfate electrolyte having a vanadium ion concentration of 80 to 160 g / L with an adsorbent and then filtering to obtain a battery-grade vanadyl sulfate electrolyte.

[0013] As a further improvement to the above technical solution:

[0014] In step S1, the volume ratio of the stock solution to the desorption solution is 5 to 10:1.

[0015] In step S1, the anion exchange resin is a sulfate-type anion exchange resin; the type of the sulfate-type anion exchange resin includes one or more of IRA-400, IRA-401, IRA-402, IRA-410, D317, D201, 717, and 312.

[0016] In step S1, the vanadium ion concentration of the vanadium leaching solution is 1.0-20 g / L, which is obtained by using vanadium-containing minerals or waste vanadium-containing materials as raw materials, leaching by water, acid or alkali, and then adjusting the pH value to neutral with a pH regulator.

[0017] The vanadium-containing minerals are one or more of stone coal, vanadium slag, vanadium-titanium magnetite, vanadium-lead-zinc ore and vanadium-containing uranium ore, and the waste vanadium-containing substances are one or both of waste vanadium-based catalysts and vanadium-containing smelting slag.

[0018] The pH regulator is one or more of sulfuric acid, sodium hydroxide and sodium carbonate.

[0019] In step S2, the organic extraction phase further comprises TBP and kerosene, the volume content of the extractant is 10% to 20%, the volume content of TBP is 0% to 5%, and the rest is kerosene;

[0020] During extraction, the volume ratio of the aqueous phase to the organic phase is 1:1 to 3:1, the temperature is room temperature, the extraction time is 5 to 30 minutes, and the pH value of the aqueous phase is 1.5 to 3.0.

[0021] In step S2, the extractant is one or more of di-2-ethylhexyl phosphoric acid, 2-ethylhexyl phosphoric acid-mono-2-ethylhexyl ester, and bis-2,4,4-trimethylpentylphosphonic acid.

[0022] In step S2, during back extraction, the ratio of the aqueous phase to the organic phase is 1:1 to 1:5, the temperature is room temperature, and the back extraction time is 5 to 30 minutes.

[0023] In step S3, the adsorbent is one or more of activated carbon, silica gel, and molecular sieve; the adsorption time is 5 to 2 hours, and the amount of the adsorbent is 100 to 500 g per ton of electrolyte.

[0024] Compared with the prior art, the advantages of the present invention are:

[0025] The present invention uses a vanadium leachate to prepare a battery-grade vanadyl sulfate electrolyte. Desorption and reduction are carried out simultaneously, which can achieve the purpose of simultaneously / synchronously achieving the removal of cationic impurities in the leachate, partial removal of anionic impurities, reduction of pentavalent vanadium and enrichment of vanadium ions. Compared with the steps of first completely adsorbing, then completely desorbing and then reducing in the prior art, the main technical idea of ​​the present invention is to first adsorb the vanadate anions in the vanadium leachate by ion exchange resin, and then use sulfurous acid solution or saturated SO2 solution to reduce the pentavalent vanadate anions (VO3 - etc.) are reduced to tetravalent VO 2+Cations (other anion impurities still remain on the ion resin, can more thoroughly remove the impurity ions in vanadium leaching solution), through chemical reaction, the reduction and desorption of vanadium ions are realized at the same time. Compared with the traditional ion exchange resin adsorption-desorption, the present application can realize the enrichment and reduction of vanadium ions at the same time, and the selectivity of vanadium ions is stronger, so that the complete removal of cation impurities and the removal of most of the anion impurities can be realized at the same time. In addition, compared with the existing desorption method using concentration difference, the desorption process of the present application only needs the reduction reaction of vanadium atoms to be sufficient to realize the desorption of vanadium ions from the resin, which can greatly reduce the amount of desorbent in theory, and can reduce the other impurity anions adsorbed in the resin to be desorbed into the desorption solution in theory, so that higher enrichment degree and purity of vanadium ions can be realized. The present application simplifies the step process, saves the production time, and improves the production efficiency. Not only can the effective removal of ion impurity elements be realized (removal rate > 90%), but also low-concentration (1.0-20g / L) vanadium leaching solution can be enriched and reduced to convert into medium-concentration (20-40g / L) VOSO4 solution at the same time.

[0026] The present application is a method for preparing battery-grade vanadyl sulfate electrolyte from vanadium leaching solution. For medium-concentration (20-40g / L) VOSO4 solution, the extraction-back extraction process is used to realize the further enrichment of vanadium ions and the further removal of impurity ions at the same time / synchronously. Alkyl phosphonic acid, alkyl phosphoric acid, alkyl phosphinic acid and other types of extractants have good extraction performance for vanadium ions and no extraction effect for anions. Although they can achieve good extraction for metal cations such as Fe 3+ , Mn 2+ , etc., since the raw material for extraction is the vanadium leaching solution treated by ion exchange resin adsorption + desorption solution desorption, the impurity cations have been effectively removed, and the chemical valence state of vanadium ions has been reduced to +4, so there are few impurity cations in the solution after extraction, even if the extractant has a certain extraction effect for impurity cations. However, the impurity cations in the vanadium solution have been effectively removed after the pretreatment of ion exchange resin adsorption-desorption solution desorption. The extraction-back extraction process of the present application can effectively realize the deep enrichment of vanadium ions. After the organic phase after extraction is washed, it is back extracted with sulfuric acid solution to prepare high-concentration (80-160g / L) VOSO4 electrolyte.

[0027] The present application is a method for preparing battery-grade vanadyl sulfate electrolyte from vanadium leaching solution. The neutral impurities in the back extraction solution are treated by using adsorbents, and the residual organic phase and other impurities in the electrolyte are removed by using the adsorption of the adsorbents, so as to finally prepare the battery-grade vanadyl sulfate electrolyte. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is the process flow chart of the present application. DETAILED DESCRIPTION

[0029] The present invention will be described in further detail below. Unless otherwise specified, the instruments and materials used in the present invention are commercially available.

[0030] Example 1:

[0031] like Figure 1 As shown, a method of preparing a battery-grade vanadyl sulfate electrolyte using a vanadium leaching solution according to this embodiment includes the following steps:

[0032] S1: Ion exchange resin adsorption-desorption pretreatment

[0033] The raw material is vanadium-extracted water extract from vanadium-titanium magnetite, with a vanadium concentration of 3.5 g / L and a weakly alkaline pH.

[0034] The ion exchange resin adsorption-desorption pretreatment equipment is a countercurrent regenerative ion exchanger. The ion exchange resin is sulfuric acid-type IRA-400. The desorption solution is a 3 mol / L sulfurous acid solution, and the volume ratio of vanadium leachate to desorption solution is 8:1. During operation, the vanadium leachate flows from top to bottom through the resin layer, adsorbing vanadium ions. During resin regeneration, the regeneration solution flows from bottom to top through the resin layer, fully reducing and desorbing the vanadium ions.

[0035] After desorption, the concentration of vanadium ions in the solution reached 28g / L, and all of them had been reduced to VOSO4. All cationic and most anionic impurities in the vanadium leachate were effectively removed, but some SO3 remained in the desorption solution after desorption. 2- The ions are processed in the next step.

[0036] S2: Extraction-Washing-Stripping

[0037] The extraction was performed using a multi-stage extraction tank, with an extractant composition of 15% P507 + kerosene, an aqueous phase to organic phase ratio of 1:1, an extraction temperature of room temperature, an extraction time of 15 minutes, an aqueous phase pH of 2.0, and three-stage countercurrent extraction. After the extraction was completed, the liquids were separated, and the organic phase was washed with a 0.02 mol / L sulfuric acid solution. The back extraction used a 2 mol / L sulfuric acid solution, and the back extraction process had an aqueous phase to organic phase volume ratio of 5:1, a temperature of room temperature, a back extraction time of 15 minutes, and three-stage countercurrent back extraction.

[0038] After stripping, the vanadium ion concentration in the solution reaches 140g / L, and the residual SO3 2- Ions and other impurity ions are effectively removed.

[0039] The present invention adopts alkylphosphonic acid, alkylphosphoric acid, alkylphosphinic acid and other types of extractants to extract VO 2+The extraction performance of ions is good, but it has no extraction effect on anions. Extractants such as P204 and P507 have stronger extraction capabilities for +4 valence vanadium ions than +5 valence vanadium ions. The present invention reduces the vanadium ions to +4 valence before extraction, which improves the extraction efficiency.

[0040] During extraction, the volume ratio of the aqueous phase to the organic phase is 1:1 to 3:1, and during stripping, the volume ratio is 1:1 to 1:5. This facilitates a four-fold increase in the concentration of the vanadium solution after extraction and stripping. The extractants P204 and P507 used in this embodiment generally achieve optimal extraction efficiency when the aqueous phase to organic phase ratio is 1:1 to 3:1. Too little organic phase often significantly reduces the vanadium extraction rate, resulting in significant vanadium loss. The aqueous phase to organic phase ratio of the present invention better ensures vanadium extraction efficiency and recovery.

[0041] S3: Adsorbent adsorption

[0042] Activated carbon was used for adsorption, and the adsorption time was 60 min;

[0043] S4: Filter

[0044] The vanadium solution was filtered using suction to obtain a vanadyl sulfate electrolyte. Measurements showed that the vanadium ion concentration in the vanadyl sulfate electrolyte reached 140g / L, with iron ≤5mg / L, sodium ≤5mg / L, silicon ≤5mg / L, aluminum ≤3mg / L, and calcium ≤3mg / L, far exceeding the national standard for first-grade vanadium battery electrolyte.

[0045] Example 2:

[0046] A method of preparing a battery-grade vanadyl sulfate electrolyte using a vanadium leaching solution according to this embodiment includes the following steps:

[0047] S1: Ion exchange resin adsorption-desorption pretreatment

[0048] The raw material is vanadium slag vanadium extraction water solution, the vanadium concentration is 5.1g / L, and the pH is weakly alkaline.

[0049] The ion exchange resin adsorption-desorption pretreatment equipment is a countercurrent regenerative ion exchanger using sulfuric acid-type IRA-400 ion exchange resin. A 3 mol / L sulfurous acid solution is used as the desorption solution, with a controlled volume ratio of vanadium leachate to desorption solution of 5:1. During operation, the vanadium leachate flows from top to bottom through the resin layer, adsorbing vanadium ions. During resin regeneration, the regeneration solution flows from bottom to top through the resin layer, fully reducing and desorbing the vanadium ions.

[0050] After desorption, the concentration of vanadium ions in the solution reaches 25g / L, and all of them have been reduced to VOSO4. All cationic and most anionic impurities in the vanadium leachate are effectively removed, but some SO3 remains in the desorption solution after desorption. 2-The ions are processed in the next step.

[0051] S2: Extraction-Washing-Stripping

[0052] A multi-stage extraction tank is used for extraction, the extractant composition is 15% P507 + kerosene, the ratio of aqueous phase to organic phase in the extraction process is 1:1, the extraction temperature is room temperature, the extraction time is 15 minutes, the pH of the aqueous phase is 2.0, and three-stage countercurrent extraction is performed; after the extraction is completed, the liquid is separated, and the organic phase is washed with 0.02 mol / L sulfuric acid solution; 2 mol / L sulfuric acid solution is used for back extraction, the ratio of aqueous phase to organic phase in the back extraction process is 4:1, the temperature is room temperature, the back extraction time is 15 minutes, and three-stage countercurrent back extraction is performed.

[0053] After stripping is completed, the concentration of vanadium ions in the solution reaches 100g / L, and the residual SO3 2- Ions and other impurity ions are effectively removed.

[0054] S3: Adsorbent adsorption

[0055] Activated carbon was used for adsorption, and the adsorption time was 60 min;

[0056] S4: Filter

[0057] The vanadium solution was filtered using suction to obtain a vanadyl sulfate electrolyte. Measurements showed that the vanadium ion concentration in the vanadyl sulfate electrolyte reached 100g / L, with iron ≤5mg / L, sodium ≤5mg / L, silicon ≤5mg / L, aluminum ≤3mg / L, and calcium ≤3mg / L, far exceeding the national standard for first-grade vanadium battery electrolyte.

[0058] Example 3:

[0059] A method of preparing a battery-grade vanadyl sulfate electrolyte using a vanadium leaching solution according to this embodiment includes the following steps:

[0060] S1: Neutralization

[0061] The raw material is vanadium acid leaching solution extracted from low-grade vanadium ore, with a vanadium concentration of 2.5g / L and a pH of 0.5. The vanadium acid leaching solution is neutralized with NaOH, and the pH of the vanadium solution after neutralization is around 7.0;

[0062] S2: Ion exchange resin adsorption-desorption pretreatment

[0063] The pretreatment equipment is a countercurrent regenerative ion exchanger, using sulfuric acid-type IRA-400 ion exchange resin. A 2 mol / L sulfurous acid solution is used as the desorption solution, with a controlled ratio of vanadium leachate to desorption solution of 10:1. During operation, the vanadium leachate flows from top to bottom through the resin layer, adsorbing vanadium ions. During resin regeneration, the desorption solution, acting as the regeneration solution, flows from bottom to top through the resin layer, fully reducing and desorbing the vanadium ions.

[0064] After desorption, the concentration of vanadium ions in the solution reaches 20g / L, and all of them have been reduced to VOSO4. All cationic and most anionic impurities in the vanadium leachate are effectively removed, but some SO3 2- The ions are processed in the next step.

[0065] S3: Extraction-Washing-Stripping

[0066] A multi-stage extraction tank is used for extraction, the extractant composition is 15% P507 + kerosene, the ratio of aqueous phase to organic phase in the extraction process is 1:1, the extraction temperature is room temperature, the extraction time is 15 minutes, the pH of the aqueous phase is 2.0, and three-stage countercurrent extraction is performed; after the extraction is completed, the liquid is separated, and the organic phase is washed with 0.02 mol / L sulfuric acid solution; 2 mol / L sulfuric acid solution is used for back extraction, the ratio of aqueous phase to organic phase in the back extraction process is 5:1, the temperature is room temperature, the back extraction time is 15 minutes, and three-stage countercurrent back extraction is performed.

[0067] After stripping is completed, the vanadium ion concentration in the solution reaches 120g / L, and the residual SO3 2- Ions and other impurity ions are effectively removed.

[0068] S4: Adsorbent adsorption

[0069] Activated carbon was used for adsorption, and the adsorption time was 60 min;

[0070] Step 6: Filter

[0071] The vanadium solution was filtered using suction to obtain a vanadyl sulfate electrolyte. Measurements showed that the vanadium ion concentration in the vanadyl sulfate electrolyte reached 120g / L, with iron ≤5mg / L, sodium ≤5mg / L, silicon ≤5mg / L, aluminum ≤3mg / L, and calcium ≤3mg / L, far exceeding the national standard for first-grade vanadium battery electrolyte.

[0072] Comparative Example 1:

[0073] A method for preparing a battery-grade vanadyl sulfate electrolyte using a vanadium leaching solution in this comparative example is substantially the same as that in Example 1, except that step S1 is different. Step S1 includes the following steps:

[0074] The raw material is vanadium-extracted water extract from vanadium-titanium magnetite, with a vanadium concentration of 3.5 g / L and a weakly alkaline pH.

[0075] The process utilizes ion exchange resin adsorption followed by sulfuric acid desorption. The equipment utilizes a countercurrent regenerative ion exchanger, sulfuric acid-type IRA-400 ion exchange resin, and a 3 mol / L sulfuric acid solution as the desorption solution. The volume ratio of vanadium solution to desorption solution is controlled at 2:1. During operation, the vanadium leachate flows from top to bottom through the resin layer, adsorbing vanadium ions. During resin regeneration, the regenerated solution flows from bottom to top through the resin layer, desorbing vanadium ions.

[0076] After desorption, the vanadium ion concentration in the solution reached 7g / L, the vanadium ion recovery rate was about 90%, and the vanadium ion valence in the solution was still +5. In addition, the removal rate of impurity ions in the vanadium leachate reached more than 95%, but some impurity ions still remained, especially SiO3 2- The ion content exceeds 120 mg / L.

[0077] It can be seen that, compared with Comparative Example 1 in which the desorption liquid uses sulfuric acid solution and the volume ratio of vanadium liquid to desorption liquid is 2:1, the desorption liquid of the present invention, as well as the ratio of vanadium liquid to desorption liquid, can better improve the concentration of vanadium ions after desorption, improve the recovery rate of vanadium ions, and have a better impurity removal effect.

[0078] Comparative Example 2:

[0079] A method for preparing a battery-grade vanadyl sulfate electrolyte using a vanadium leaching solution in this comparative example is substantially the same as that in Example 1, except that step S1 is not present, and step S2 includes the following steps:

[0080] The raw material is vanadium-extracted water extract from vanadium-titanium magnetite, with a vanadium concentration of 3.5 g / L and a weakly alkaline pH.

[0081] The vanadium leachate is directly extracted by an extraction-washing-strip extraction method, wherein the extractant composition is 15% P507+kerosene, the ratio of the aqueous phase to the organic phase in the extraction process is 1:1, the extraction temperature is room temperature, the extraction time is 15 minutes, the pH value of the aqueous phase is 2.0, and three-stage countercurrent extraction is performed; after the extraction is completed, the liquid is separated, and the organic phase is washed with a 0.02 mol / L sulfuric acid solution; 2 mol / L sulfuric acid solution is used for back extraction, the ratio of the aqueous phase to the organic phase in the back extraction process is 5:1, the temperature is room temperature, the back extraction time is 15 minutes, and three-stage countercurrent back extraction is performed.

[0082] The vanadium ion concentration after stripping was about 17 g / L, and the vanadium ion recovery rate was 93.5%.

[0083] Comparative Example 3:

[0084] A method for preparing a battery-grade vanadyl sulfate electrolyte using a vanadium leaching solution in this comparative example is substantially the same as that in Example 1, except that step S1 is not present, and step S2 includes the following steps:

[0085] The vanadium leachate is directly extracted by an extraction-washing-strip extraction method, wherein the extractant composition is 15% P507+kerosene, the ratio of the aqueous phase to the organic phase in the extraction process is 5:1, the extraction temperature is room temperature, the extraction time is 15 minutes, the pH value of the aqueous phase is 2.0, and three-stage countercurrent extraction is performed; after the extraction is completed, the liquid is separated, and the organic phase is washed with a 0.02 mol / L sulfuric acid solution; 2 mol / L sulfuric acid solution is used for back extraction, the ratio of the aqueous phase to the organic phase in the back extraction process is 5:1, the temperature is room temperature, the back extraction time is 15 minutes, and three-stage countercurrent back extraction is performed.

[0086] After stripping, the vanadium ion concentration was about 60 g / L, and the vanadium ion recovery rate was only 68%.

[0087] This demonstrates that, compared to the direct extraction and stripping methods of Comparative Examples 2 and 3, the present invention, which performs ion resin adsorption and reduction desorption pretreatment prior to extraction, can advantageously improve the vanadium ion concentration and recovery rate after extraction. Furthermore, Comparative Example 3 demonstrates that, compared to Comparative Example 2, the vanadium ion concentration in the vanadium leachate can be increased to 60 g / L simply by significantly increasing the ratio of the aqueous phase to the organic phase during the extraction process. However, the vanadium ion recovery rate is significantly reduced, resulting in a significant loss of vanadium ions.

[0088] Although the present invention has been disclosed above with reference to preferred embodiments, this is not intended to limit the present invention. Any person skilled in the art can, without departing from the scope of the technical solution of the present invention, utilize the technical content disclosed above to make many possible changes and modifications to the technical solution of the present invention, or modify it into an equivalent embodiment with equivalent changes. Therefore, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for preparing a battery-grade vanadyl sulfate electrolyte using a vanadium leachate, characterized in that: The following steps are involved: S1. Using a vanadium ion concentration of 1.0 to 20 g / L vanadium leachate as a stock solution and a sulfurous acid solution or a saturated SO2 solution as a desorption solution, the stock solution is allowed to flow from one end of an anion exchange resin to the other end for adsorption treatment, and the desorption solution is allowed to flow from the ion exchange resin in the opposite direction for elution reduction desorption treatment to obtain a vanadyl sulfate solution with a vanadium ion concentration of 20 to 40 g / L; S2, extracting and stripping a vanadyl sulfate solution having a vanadium ion concentration of 20 to 40 g / L to obtain a vanadyl sulfate electrolyte having a vanadium ion concentration of 80 to 160 g / L; extracting with an organic extraction phase, wherein the extractant of the organic extraction phase is one or more of alkylphosphonic acid, alkylphosphoric acid, and alkylphosphinic acid; stripping with a stripping agent, wherein the stripping agent is a sulfuric acid solution having a concentration of 1.0 to 2.0 mol / L; S3, filtering a vanadyl sulfate electrolyte having a vanadium ion concentration of 80 to 160 g / L after adsorption by an adsorbent to obtain a battery-grade vanadyl sulfate electrolyte; In step S1, the volume ratio of the stock solution to the desorption solution is 5 to 10:1; In step S1, the anion exchange resin is a sulfate anion exchange resin; the type of the sulfate anion exchange resin includes one or more of IRA-400, IRA-402, IRA-410, D201, and 717; In step S2, in the organic extraction phase, the volume content of the extractant is 10% to 20%, the volume content of TBP is 0% to 5%, and the rest is kerosene; During extraction, the volume ratio of the aqueous phase to the organic phase is 1:1 to 3:1, the temperature is room temperature, the extraction time is 5 to 30 minutes, and the pH value of the aqueous phase is 1.5 to 3.

0.

2. The method according to claim 1, wherein: In step S1, the vanadium ion concentration of the vanadium leaching solution is 1.0-20 g / L, which is obtained by using vanadium-containing minerals or waste vanadium-containing materials as raw materials, leaching by water, acid or alkali, and then adjusting the pH value to neutral with a pH regulator.

3. The method according to claim 2, wherein: The vanadium-containing minerals are one or more of stone coal, vanadium-titanium magnetite, vanadium-lead-zinc ore and vanadium-containing uranium ore, and the waste vanadium-containing substances are one or both of waste vanadium-based catalysts and vanadium-containing smelting slag.

4. The method according to claim 2, wherein: The pH regulator is one or more of sulfuric acid, sodium hydroxide and sodium carbonate.

5. The method according to any one of claims 1 to 4, characterized in that: In step S2, the extractant is one or more of di(2-ethylhexyl)phosphoric acid, 2-ethylhexyl phosphate-mono-2-ethylhexyl ester, and bis(2,4,4-trimethylpentyl)phosphonic acid.

6. The method according to any one of claims 1 to 4, characterized in that: In step S2, during back extraction, the ratio of the aqueous phase to the organic phase is 1:1 to 1:5, the temperature is room temperature, and the back extraction time is 5 to 30 minutes.

7. The method according to any one of claims 1 to 4, characterized in that: In step S3, the adsorbent is one or more of activated carbon, silica gel, and molecular sieve; the adsorption time is 5 to 2 hours, and the amount of the adsorbent is 100 to 500 g per ton of electrolyte.

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