Method for preparing battery grade vanadyl sulfate electrolyte by using vanadium leachate

Abstract

The invention discloses a method for preparing a battery-grade vanadyl sulfate electrolyte by using a vanadium leachate, which comprises the following steps: S1, carrying out anion resin adsorption-desorption treatment and reduction treatment by using the vanadium leachate with the vanadium ion concentration of 1.0-20g / L as a stock solution and using a sulfurous acid solution or a saturated SO2 solution as a desorption solution to obtain a vanadyl sulfate solution with the vanadium ion concentration of 20-40g / L; the method comprises the following steps: sequentially performing extraction and back extraction on a vanadyl sulfate solution with the vanadium ion concentration of 20-40g / L to obtain a vanadyl sulfate electrolyte with the vanadium ion concentration of 80-160g / L; and S3, adsorbing the vanadyl sulfate electrolyte with the vanadium ion concentration of 80-160g / L by using an adsorbent, and filtering to obtain the battery-grade vanadyl sulfate electrolyte. According to the method, the removal of impurities in the vanadium leachate and the efficient reduction conversion and enrichment purification of vanadium ions can be simultaneously / synchronously realized, and the technical effects of improving the product quality, shortening the process flow, improving the production efficiency and reducing the production cost are achieved.

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] The electrolyte of vanadium batteries generally uses high-purity VOSO4 (vanadium oxysulfate) as the core raw material. After pre-electrolysis treatment, the positive and negative electrolytes of the required valence states can be obtained. At present, the main method for large-scale production of vanadium oxysulfate electrolytes is through chemical reduction, using reducing substances to dissolve high-purity V2O5 and reduce it to VOSO4. However, the high cost of high-purity V2O5 directly leads to the high production cost of the electrolyte, which restricts the promotion and application of vanadium batteries. In addition, some studies have attempted to use a suspension of V2O5 and sulfuric acid for electrolysis to prepare electrolytes of different valence states. Although this method can effectively control the introduction of impurity elements, its production efficiency is low, the energy consumption is huge, and it is difficult to meet the needs of large-scale production. It is currently limited to small-scale laboratory applications. In order to solve the technical bottleneck of the high cost of vanadium battery electrolytes, it is critical to find low-cost production raw materials and develop stable, mature and large-scale production processes and technologies. Broadening the sources of low-cost vanadium electrolyte raw materials can be traced back to the upstream of the vanadium industry chain. For example, the vanadium extraction leaching solution of 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 the preparation of VOSO4 vanadium battery electrolyte. This requires the enrichment and reduction of vanadium ions in the leaching solution and the removal of impurity ions.

[0003] The 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 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 in steps is long and the steps are relatively complicated.

[0004] Some processes and technologies directly use extraction or ion exchange to enrich vanadium ions and remove impurity ions. However, the concentration of vanadium ions in the vanadium-containing leachate is low. In order to make the vanadium ion concentration in the solution meet the requirements of the vanadium battery electrolyte, the vanadium ion concentration usually needs to be enriched by 20 to 70 times. In order to meet the requirements of the vanadium battery electrolyte for the vanadium ion concentration, the existing technology has to reduce the extraction ratio or significantly reduce the amount of ion exchange resin and desorption solution in order to enrich the concentration of vanadium ions, which will lead to a significant decrease in the recovery rate and enrichment efficiency of vanadium. Therefore, it is difficult for the existing extraction method or ion resin exchange method to simultaneously ensure the concentration and recovery rate of vanadium ions. In addition, the multiple / multi-stage extraction operations 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 battery operation and seriously shorten the battery life.

[0005] Some existing technologies do not use a single ion exchange method or extraction method to prepare vanadium electrolyte. Instead, they combine ion exchange and extraction methods to purify the leaching solution by ion exchange, and then use solvent extraction and back extraction to concentrate it. The applicant found that in this type of technical solution, the ion exchange purification step is carried out step by step. The leaching solution is first adsorbed by wet resin, and then desorbed by sulfuric acid (salt) solution after the resin is saturated. Although this type of technical solution can also purify the leaching solution, its desorption principle is to use SO4 2- The concentration difference makes VO3 - , Cl - 、SiO3 2- There are the following technical problems in the back adsorption of anions from the resin: 1. The obtained solution still inevitably contains a certain amount of impurity anions; 2. The valence state of the vanadium ion is still +5, and it needs to be reduced later, which makes the process steps complicated and the treatment process long; 3. The amount of desorption liquid required is large; 4. For the leachate with more impurity ions, it is still necessary to remove impurities and purify the leachate before ion exchange purification, and then perform ion exchange purification, which undoubtedly limits the types of leachates, increases production time and cost, and reduces production efficiency.

[0006] Therefore, current processes and technologies generally have problems such as long process flow, low efficiency, and low vanadium ion recovery rate. Summary of the invention

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

[0008] In order to solve the above technical problems, the present invention adopts the following technical solutions:

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

[0010] S1, using a vanadium leaching solution with a vanadium ion concentration of 1.0 to 20 g / L as a stock solution, and a sulfurous acid solution or a saturated SO2 solution as a desorption solution, the stock solution is flowed from one end of an anion exchange resin to the other end for adsorption treatment, and the desorption solution is flowed 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 vanadium ion concentration of 20 to 40 g / L vanadyl sulfate solution to obtain a vanadium ion concentration of 80 to 160 g / L vanadyl sulfate electrolyte; extracting with an organic extraction phase, wherein the extractant of the organic extraction phase is one or more of alkyl phosphonic acid, alkyl phosphoric acid, and alkyl phosphinic acid, and stripping with a stripping agent, wherein the stripping agent is a sulfuric acid solution with a concentration of 1.0 to 2.0 mol / L;

[0012] S3. The vanadyl sulfate electrolyte having a vanadium ion concentration of 80 to 160 g / L is adsorbed by an adsorbent and then filtered 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 is 1.0-20 g / L. The vanadium leaching solution is made of vanadium-containing minerals or waste vanadium-containing materials as raw materials, and is obtained by water leaching, acid leaching or alkali leaching, 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 adjuster is one or more of sulfuric acid, sodium hydroxide and sodium carbonate.

[0019] In step S2, the organic extraction phase also includes 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 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 the 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 / ton of electrolyte.

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

[0025] The method for preparing a battery-grade vanadyl sulfate electrolyte by using a vanadium leachate is provided by the present invention. Desorption and reduction are performed simultaneously, and 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 can be achieved. 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 firstly adsorb the vanadate anions in the vanadium leachate by an ion exchange resin, and then use a sulfurous acid solution or a saturated SO2 solution to convert the pentavalent vanadate anions (VO3 - etc.) to tetravalent VO 2+Cations (other anionic impurities still remain on the ion resin, which can more thoroughly remove the impurity ions in the vanadium leachate), and the reduction and desorption of vanadium ions are simultaneously achieved through chemical reactions. Compared with the traditional ion exchange resin adsorption-desorption, the present invention can simultaneously achieve the enrichment and reduction of vanadium ions, and the selectivity of vanadium ions is relatively strong, so that the complete removal of cationic impurities and the majority of anionic impurities can be achieved at the same time. In addition, compared with the existing method of desorption using concentration difference, the desorption process of the present invention only requires the reduction reaction of vanadium atoms to be sufficient to achieve the desorption of vanadium ions from the resin, which can theoretically greatly reduce the amount of desorbent used, and theoretically reduce other impurity anions adsorbed in the resin from being desorbed into the desorption solution, thereby achieving a higher degree of vanadium ion enrichment and purity. The present invention simplifies the process steps, saves production time, and improves production efficiency. It can not only effectively remove ionic impurity elements (removal rate>90%), but also simultaneously enrich and reduce low-concentration (1.0-20 g / L) vanadium leaching solution into a medium-concentration (20-40 g / L) VOSO4 solution.

[0026] The present invention uses vanadium leaching solution to prepare a battery-grade vanadium sulfate electrolyte. For a medium concentration (20-40 g / L) VOSO4 solution, an extraction-stripping process is used to simultaneously / synchronously achieve further enrichment of vanadium ions and further removal of impurity ions. Alkylphosphonic acid, alkyl phosphoric acid, alkyl phosphinate and other types of extractants have good extraction performance for vanadium ions and have no extraction effect on anions. Although Fe 3+ , Mn 2+ The metal cations can also be extracted well, but during the extraction, the raw material is the vanadium leachate after ion exchange resin adsorption + desorption liquid desorption treatment, in which the impurity cations have been effectively removed, and the chemical valence of the vanadium ions has been reduced to +4 valence, so there are fewer impurity cations in the solution after extraction. Even if the extractant has a certain extraction effect on the impurity cations, the impurity cations in the vanadium solution have been effectively removed after ion exchange resin adsorption-desorption liquid desorption pretreatment. The extraction-strip extraction process of the present invention can effectively achieve deep enrichment of vanadium ions. The organic phase after extraction is washed and then stripped with sulfuric acid solution to prepare a high concentration (80-160g / L) VOSO4 electrolyte.

[0027] The invention discloses a method for preparing a battery-grade vanadyl sulfate electrolyte by using a vanadium leaching solution, wherein an adsorbent is used to treat electrically neutral impurities in a stripping solution, and an adsorption effect of the adsorbent is used to remove residual organic phase and other impurities in the electrolyte, thereby finally preparing a battery-grade vanadyl sulfate electrolyte. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

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

[0030] Embodiment 1:

[0031] like Figure 1 As shown, a method for preparing a battery-grade vanadyl sulfate electrolyte using vanadium leaching solution in 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, the vanadium concentration is 3.5 g / L, and the pH is weakly alkaline.

[0034] The ion exchange resin adsorption-desorption pretreatment equipment is a countercurrent regeneration ion exchanger, the ion exchange resin is sulfuric acid type IRA-400, the desorption liquid uses 3mol / L sulfurous acid solution, and the volume ratio of vanadium leaching solution to desorption liquid is 8:1. When the equipment is running, the vanadium leaching liquid flows from top to bottom through the resin layer to adsorb vanadium ions; when the resin is regenerated, the regeneration liquid passes through the resin layer from bottom to top to fully reduce and desorb vanadium ions.

[0035] After desorption, the vanadium ion concentration in the solution reached 28g / L, and all of them had been reduced to VOSO4. All cationic and most anionic impurities in the vanadium leaching solution 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] 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, liquid separation is performed, and the organic phase is washed with a 0.02 mol / L sulfuric acid solution; a 2 mol / L sulfuric acid solution is used for back extraction, the volume 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;

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

[0039] The present invention adopts alkyl phosphonic acid, alkyl phosphoric acid, alkyl phosphinic acid and other types of extractants to extract VO 2+The extraction performance of ions is good, and it has no extraction effect on anions. The extraction ability of P204, P507 and other extractants for +4 valence vanadium ions is stronger than that for +5 valence. The present invention reduces the vanadium ions to +4 valence before extraction, and the extraction efficiency is higher.

[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 of the aqueous phase to the organic phase is 1:1 to 1:5, which is convenient for increasing the concentration of the vanadium solution by about 4 times after extraction and stripping. The extractants P204 and P507 used in this embodiment usually have a better extraction effect when the ratio of the aqueous phase to the organic phase is 1:1 to 3:1. If the organic phase is too little, the vanadium extraction rate often drops significantly, which will cause a large amount of vanadium loss. The ratio of the aqueous phase to the organic phase of the present invention can better ensure the extraction efficiency and recovery rate of vanadium.

[0041] S3: Adsorption by adsorbent

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

[0043] S4: Filter

[0044] The vanadium liquid is filtered by suction to obtain vanadium sulfate electrolyte. After measurement, the vanadium ion concentration of vanadium sulfate electrolyte can reach 140g / L, iron ≤5mg / L, sodium ≤5mg / L, silicon ≤5mg / L, aluminum ≤3mg / L, calcium ≤3mg / L, which is much higher than the national standard first-grade requirements of vanadium battery electrolyte.

[0045] Embodiment 2:

[0046] A method for preparing a battery-grade vanadyl sulfate electrolyte using 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 regeneration ion exchanger, the ion exchange resin is sulfuric acid type IRA-400, the desorption liquid uses 3mol / L sulfurous acid solution, and the volume ratio of vanadium leaching solution to desorption liquid is controlled to be 5:1. When the equipment is running, the vanadium leaching liquid flows from top to bottom through the resin layer to adsorb vanadium ions; when the resin is regenerated, the regeneration liquid passes through the resin layer from bottom to top to fully reduce and desorb vanadium ions.

[0050] After desorption, the vanadium ion concentration in the solution reached 25g / L, and all of them had been reduced to VOSO4. All cationic and most anionic impurities in the vanadium leaching solution were effectively removed, but some SO3 remained 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 a 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, the vanadium ion concentration in the solution reaches 100g / L, and the residual SO3 2- Ions and other impurity ions are effectively removed.

[0054] S3: Adsorption by adsorbent

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

[0056] S4: Filter

[0057] The vanadium liquid is filtered by suction to obtain vanadium sulfate electrolyte. After measurement, the vanadium ion concentration of vanadium sulfate electrolyte can reach 100g / L, iron ≤5mg / L, sodium ≤5mg / L, silicon ≤5mg / L, aluminum ≤3mg / L, calcium ≤3mg / L, which is much higher than the national standard first-grade requirements of vanadium battery electrolyte.

[0058] Embodiment 3:

[0059] A method for preparing a battery-grade vanadyl sulfate electrolyte using 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 about 7.0;

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

[0063] The pretreatment equipment is a countercurrent regeneration ion exchanger, the ion exchange resin is sulfuric acid type IRA-400, the desorption liquid uses 2mol / L sulfurous acid solution, and the ratio of vanadium leaching liquid to desorption liquid is controlled to be 10:1. When the equipment is running, the vanadium leaching liquid flows from top to bottom through the resin layer to adsorb vanadium ions; when the resin is regenerated, the desorption liquid is used as the regeneration liquid to fully reduce and desorb the vanadium ions through the resin layer from bottom to top.

[0064] After desorption, the concentration of vanadium ions in the solution reached 20g / L, and all of them had been reduced to VOSO4. All cationic and most anionic impurities in the vanadium leaching solution were effectively removed, but some SO3 remained in the desorption solution after desorption. 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 a 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, 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: Adsorption by adsorbent

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

[0070] Step 6: Filter

[0071] The vanadium liquid is filtered by suction to obtain vanadium sulfate electrolyte. After measurement, the vanadium ion concentration of vanadium sulfate electrolyte can reach 120g / L, iron ≤5mg / L, sodium ≤5mg / L, silicon ≤5mg / L, aluminum ≤3mg / L, calcium ≤3mg / L, which is much higher than the national standard first-grade requirements of vanadium battery electrolyte.

[0072] Comparative Example 1:

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

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

[0075] The method of ion exchange resin adsorption-sulfuric acid desorption is adopted. The equipment is a countercurrent regeneration ion exchanger, the ion exchange resin is sulfuric acid type IRA-400, and the desorption liquid is a 3mol / L sulfuric acid solution. The volume ratio of vanadium liquid to desorption liquid is controlled to be 2:1. When the equipment is running, the vanadium leaching liquid flows from top to bottom through the resin layer to adsorb vanadium ions; when the resin is regenerated, the regeneration liquid passes through the resin layer from bottom to top to desorb vanadium ions.

[0076] After desorption, the concentration of vanadium ions in the solution reached 7g / L, the recovery rate of vanadium ions was about 90%, and the valence of vanadium ions in the solution was still +5. In addition, the removal rate of impurity ions in the vanadium leaching solution 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 adopts 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 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, the vanadium concentration is 3.5 g / L, and the pH is weakly alkaline.

[0081] The vanadium leaching solution is directly extracted by an extraction-washing-strip extraction method, 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 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 stripping, the ratio of aqueous phase to organic phase in the stripping process is 5:1, the temperature is room temperature, the stripping time is 15 minutes, and three-stage countercurrent stripping is performed.

[0082] After stripping, the vanadium ion concentration 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 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 leaching solution is directly extracted by an extraction-washing-strip extraction method, the extractant composition is 15% P507+kerosene, the ratio of aqueous phase to 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 stripping, the ratio of aqueous phase to organic phase in the stripping process is 5:1, the temperature is room temperature, the stripping time is 15 minutes, and three-stage countercurrent stripping is performed.

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

[0087] It can be seen that, compared with the direct extraction and stripping methods of Comparative Examples 2 and 3, the present invention performs ion resin adsorption and reduction desorption pretreatment before extraction, which can help improve the vanadium ion concentration and recovery rate after extraction. In addition, compared with Comparative Example 2, Comparative Example 3 shows that the vanadium ion concentration in the vanadium leachate can be increased to 60 g / L by only greatly increasing the ratio of the aqueous phase to the organic phase in the extraction process, but the vanadium ion recovery rate is greatly reduced, resulting in a large amount of vanadium ion loss.

[0088] Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any technician familiar with the art can make many possible changes and modifications to the technical solution of the present invention by using the technical content disclosed above without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention should 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 leaching solution, characterized in that: The following steps are involved: S1, using a vanadium leaching solution with a vanadium ion concentration of 1.0 to 20 g / L as a stock solution, and a sulfurous acid solution or a saturated SO2 solution as a desorption solution, the stock solution is flowed from one end of an anion exchange resin to the other end for adsorption treatment, and the desorption solution is flowed 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 vanadium ion concentration of 20 to 40 g / L vanadyl sulfate solution to obtain a vanadium ion concentration of 80 to 160 g / L vanadyl sulfate electrolyte; extracting with an organic extraction phase, wherein the extractant of the organic extraction phase is one or more of alkyl phosphonic acid, alkyl phosphoric acid, and alkyl phosphinic acid, and stripping with a stripping agent, wherein the stripping agent is a sulfuric acid solution with a concentration of 1.0 to 2.0 mol / L; S3. The vanadyl sulfate electrolyte having a vanadium ion concentration of 80 to 160 g / L is adsorbed by an adsorbent and then filtered to obtain a battery-grade vanadyl sulfate electrolyte.

2. The method according to claim 1, characterized in that: In step S1, the volume ratio of the stock solution to the desorption solution is 5 to 10:

1.

3. The method according to claim 1, characterized in that: 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.

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

5. The method according to claim 4, characterized in that: 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.

6. The method according to claim 4, characterized in that: The pH adjuster is one or more of sulfuric acid, sodium hydroxide and sodium carbonate.

7. The method according to any one of claims 1 to 6, characterized in that: In step S2, the organic extraction phase also includes 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; 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 of the aqueous phase is 1.5 to 3.

0.

8. The method according to claim 7, characterized in that: 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.

9. The method according to claim 7, characterized in that: In step S2, during the 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.

10. The method according to any one of claims 1 to 6, 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 / ton of electrolyte.

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