Vanadium electrolyte based on vanadium shale acid leachate and preparation method thereof

Abstract

The invention relates to a vanadium electrolyte based on vanadium shale acid leachate and a preparation method of the vanadium electrolyte. According to the technical scheme, the method comprises the following steps: adjusting the pH value of the vanadium shale acid leaching solution to 1.8-2.0 to obtain an extraction stock solution; mixing the extraction organic phase with the extraction stock solution, and performing countercurrent positive extraction to obtain raffinate and a loaded organic phase; washing the loaded organic phase, and performing oxidation and reverse extraction by using a hydrogen peroxide solution and a sodium hypochlorite solution to obtain a first-section reverse extraction solution and a first-section lean organic phase; the first-stage strip liquor is reduced to obtain reduced strip liquor, the reduced strip liquor is subjected to second-stage extraction, and an obtained loaded organic phase is subjected to reverse extraction with sulfuric acid; and removing oil from a second-stage strip liquor obtained by reverse extraction to obtain the vanadium electrolyte based on the vanadium shale acid leaching solution. Therefore, the method has the advantages of being low in cost, environmentally friendly, simple in process and low in agent consumption and energy consumption, the prepared vanadium electrolyte based on the vanadium shale acid leaching solution is high in concentration and purity, and impurity separation and vanadium enrichment in the vanadium shale acid leaching solution are effectively achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of vanadium electrolyte, and specifically relates to a vanadium electrolyte based on vanadium shale acid leaching solution and a preparation method thereof. Background Art

[0002] Vanadium batteries have the advantages of rapid response, deep discharge, easy detection of charge and discharge status, high energy conversion efficiency and long service life. They are a large-scale energy storage technology with great potential. The components of vanadium batteries are bipolar plates, electrodes, proton exchange membranes and electrolytes. The properties of the electrolyte determine the energy density and electrochemical properties of the battery. At present, the mainstream process for the preparation of vanadium electrolytes is to use high-purity solid vanadium pentoxide as raw material, and reduce V2O5 through chemical reducing agents such as SO2, oxalic acid, V2O3 or electrolysis to dissolve it in sulfuric acid, but high-purity vanadium pentoxide will lead to high preparation costs.

[0003] Vanadium shale is an important vanadium source in China. Its mainstream vanadium extraction process, direct acid leaching, produces acidic vanadium-rich liquid, which is mainly V(IV), accompanied by the leaching and enrichment of impurities such as iron and aluminum. It has the characteristics of high vanadium and high impurities, which brings difficulties in deep impurity removal and enrichment for the subsequent preparation of vanadium electrolyte. The preparation of high-purity V2O5 from acidic vanadium-rich liquid requires oxidation, vanadium precipitation, alkaline dissolution and impurity removal, re-vanadium precipitation, calcination and other steps, which produces sewage and waste gas during the process, and the production process is long.

[0004] The patented technology of "A method for preparing vanadium pentoxide for metal vanadium liquid flow battery" (CN117658210A) is to first prepare crude ammonium metavanadate from vanadium ore, then react with calcium oxide and filter to obtain a filtrate, add a sulfiding agent, filter, add aluminum sulfate and then filter to obtain a filtrate after secondary impurity removal, add hydrogen peroxide solution and ammonium sulfate to react and filter to obtain a filter cake, wash, dry and calcine to obtain vanadium pentoxide, then add sulfuric acid to dissolve the vanadium pentoxide, and obtain the vanadium ion electrolyte of the metal vanadium liquid flow battery through electrolysis. The preparation of vanadium pentoxide from vanadium ore requires steps such as sulfidation and filtration, which generates sewage, affects the environment, and has a long production process.

[0005] The patented technology of "A method for preparing vanadium electrolyte from vanadium-chromium leaching solution" (CN116590544A) is to add desiliconization and reducing agent to vanadium-chromium leaching solution to obtain reduced leaching solution; adjust the pH of reduced leaching solution to preliminarily remove Cr(III) precipitation to obtain preliminarily chromium-removed filtrate; then add chromium-removing agent to remove chromium deeply to obtain deep chromium-removed filtrate; adjust the pH of deep chromium-removed filtrate, extract, wash and strip to obtain vanadium electrolyte. However, this process still requires multiple additions of reagents, with complex process flow, high reagent consumables, serious pollution and high cost.

[0006] The patented technology of "A vanadium electrolyte based on acidic vanadium-rich solution and its preparation method" (CN116314991A) is to crystallize and remove aluminum through pretreatment of acidic vanadium-rich solution, obtain clear solution after solid-liquid separation, and then obtain extraction stock solution through reduction and pH adjustment; extract vanadium from the extraction stock solution with saponified organic phosphonic acid extractant, wash the loaded organic phase with dilute acid and then strip with sulfuric acid; remove oil from the stripping solution obtained by stripping to obtain vanadium electrolyte. Although this technology is environmentally friendly and has a low extraction pH value, it has the problems of front-end impurity removal process and incomplete separation of vanadium and impurities.

[0007] The patented technology of "A method for preparing a commercial vanadium battery electrolyte" (CN103606694A) uses a chemical method to prepare a vanadium electrolyte in one step. After the vanadium-containing raw material is dissolved with alkali, the pH value is adjusted with acid and alkali, and vanadium is repeatedly precipitated to remove impurity elements. Then, vanadium oxide is obtained by roasting, and finally, the vanadium oxide is dissolved with concentrated sulfuric acid to obtain a vanadium electrolyte. Although this method can effectively remove impurities such as iron, chromium, silicon, and manganese, reduce the impurity content, and improve the purity of the product, it requires repeated vanadium precipitation, which has a complicated process flow and high reagent and energy consumption.

[0008] The patented technology of "A method for preparing high-purity electrolyte for vanadium batteries from stone coal" (CN101126124B) uses stone coal alkaline roasting and water leaching to obtain a vanadium electrolyte through impurity removal, reduction, vanadium precipitation and sulfuric acid dissolution. This technology still requires multiple reduction and oxidation vanadium precipitation and dissolution intermediate links, and the process is complicated, with high reagent and energy consumption, serious pollution and high cost.

[0009] In summary, the existing vanadium electrolyte preparation process has the problems of high preparation cost, environmental pollution, complex process, high reagent consumption and energy consumption, and the prepared vanadium electrolyte product has the problem of high concentration of impurity ions. Summary of the invention

[0010] The present invention aims to overcome the existing technical defects and aims to provide a method for preparing a vanadium electrolyte based on vanadium shale acidic leaching solution with low cost, cleanliness and high efficiency, simple process, low reagent consumption and low energy consumption. The prepared vanadium electrolyte based on vanadium shale acidic leaching solution has high concentration and high purity, and can effectively separate impurities in the vanadium shale acidic leaching solution and enrich vanadium.

[0011] To achieve the above object, the technical solution adopted by the present invention is:

[0012] Step 1: Adjust pH

[0013] A pH regulator is added to the vanadium shale acid leaching solution to adjust the pH to 1.8-2.0 to obtain an extraction stock solution.

[0014] The chemical composition of the vanadium shale acid leaching solution is: V is 1600-2000 mg / L, Al is 5000-8000 mg / L, Fe is 5000-8000 mg / L, Mg is 1000-3000 mg / L, Na is 1000-3000 mg / L, K is 1000-3000 mg / L, and Ca is 200-500 mg / L.

[0015] The pH of the vanadium shale acidic leaching solution is 0-1.

[0016] Step 2: Primary extraction and stripping

[0017] Step 2.1, according to the volume ratio of the extracted organic phase to the extracted stock solution of 1: (1 to 3), the extracted organic phase and the extracted stock solution are mixed, and countercurrent extraction is performed at 10 to 50° C. The countercurrent extraction stage is 3 to 6, and the countercurrent extraction time is 8 to 12 min. Phase separation is performed to obtain a raffinate and a loaded organic phase.

[0018] The extraction organic phase is a mixture prepared by mixing 15-30 vol% of vanadium extractant, 5 vol% of tributyl phosphate and 65-80 vol% of sulfonated kerosene.

[0019] Step 2.2, according to the volume ratio of the loaded organic phase to the detergent being 1:(1-3), the loaded organic phase and the detergent are mixed, stirred at 10-30° C. for 10-40 min, and phase separated to obtain washing water and a washed loaded organic phase.

[0020] The detergent is 0.01-0.05 mol / L dilute sulfuric acid or deionized water.

[0021] Step 2.3, according to the volume ratio of the washed loaded organic phase to the first-stage stripping agent of (1-4):1, the washed loaded organic phase is mixed with the first-stage stripping agent, and single-stage stripping is carried out at 40-60°C for 8-12 minutes, and the phases are separated to obtain a first-stage stripping liquid and a first-stage lean organic phase.

[0022] The first-stage stripping agent is a mixture prepared by mixing the sodium hypochlorite solution and the hydrogen peroxide solution according to a volume ratio of sodium hypochlorite solution to hydrogen peroxide solution of (0.081-0.143):1; wherein the mass concentration of the hydrogen peroxide solution is 1.5-6%, and the mass concentration of the sodium hypochlorite is 6-10%.

[0023] Step 3: Reduction and pH adjustment

[0024] Step 3.1, according to the ratio of the amount of reducing agent: vanadium in the first stripping solution of (1.2-2):1; add the reducing agent to the first stripping solution, stir at 10-30° C. for 10-30 minutes, and obtain a reduced stripping solution.

[0025] Step 3.2, adding 3% by volume of dilute sulfuric acid to the reduced stripping solution, adjusting the pH to 1.5-3, and obtaining a vanadium-rich solution after adjusting the pH.

[0026] Step 4: Secondary extraction and stripping

[0027] Step 4.1, according to the volume ratio of the extracted organic phase to the vanadium-rich solution after adjusting the pH being 1: (1-3), the extracted organic phase and the vanadium-rich solution after adjusting the pH are mixed, and countercurrent extraction is performed at 10-50° C., the countercurrent extraction stage is 3-6, the countercurrent extraction time is 8-12 min, and the phases are separated to obtain a raffinate and a loaded organic phase.

[0028] The organic phase extracted in this step is the same as the organic phase extracted in step 2.1.

[0029] Step 4.2, according to the volume ratio of the loaded organic phase to the second-stage stripping agent of (1-8):1, the loaded organic phase and the second-stage stripping agent are mixed, countercurrent stripping is performed at 10-30°C, the countercurrent stripping stage is 3-6, the countercurrent stripping time is 30-50min, and the phases are separated to obtain a second-stage stripping liquid and a second-stage lean organic phase.

[0030] Step 5: Degreasing

[0031] Step 5.1: Deoil the second-stage stripping solution to obtain a vanadium electrolyte V(IV) based on a vanadium shale acidic leaching solution.

[0032] The vanadium electrolyte V(IV): V concentration is 90-135.0 g / L, Al concentration is ≤5 mg / L, Fe concentration is ≤5 mg / L, Mg concentration is ≤3 mg / L, Na concentration is ≤10 mg / L, K concentration is ≤10 mg / L, and Ca concentration is ≤30 mg / L.

[0033] The vanadium shale acidic leaching solution has a valence state of tetravalent vanadium and a valence state of divalent iron.

[0034] The pH adjuster is sodium hydroxide or sodium bicarbonate.

[0035] The vanadium extractant is di(2-ethylhexyl) phosphate or 2-ethylhexylphosphonic acid mono(2-ethylhexyl) ester.

[0036] The reducing agent is one of oxalic acid, ascorbic acid, citric acid and sulfurous acid.

[0037] The second-stage stripping agent is 2-6 mol / L sulfuric acid.

[0038] The oil removal treatment is carried out by using one of clarification tank clarification, resin flotation column adsorption and activated carbon adsorption.

[0039] Due to the adoption of the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0040] 1. The present invention has low preparation cost, clean and efficient, simple process, less consumables and low energy consumption.

[0041] The present invention uses vanadium shale acid leachate as raw material, and realizes the preparation of vanadium electrolyte based on vanadium shale acid leachate through "pretreatment-one-stage extraction-reduction-two-stage extraction". Compared with the existing "extraction-oxidation-vanadium precipitation-alkali dissolution-vanadium precipitation-calcination-reduction and dissolution in sulfuric acid" process, it reduces oxidation, multiple vanadium precipitation, alkali dissolution, and high-temperature calcination links, avoids the use of a large number of reagents and high-temperature reactions, thereby reducing the cost of reagent consumables and streamlining the process. Therefore, the present invention has less reagent consumables, low energy consumption, low preparation cost, short process flow, and is clean and efficient.

[0042] 2. The present invention has good impurity separation effect, high electrolyte concentration and high purity

[0043] The invention utilizes a hydrogen peroxide solution and a sodium hypochlorite solution to oxidize and strip the vanadium (IV) and iron (II) in the vanadium shale acid leaching solution to oxidize to vanadium (V) and iron (III), respectively, and the high-valent impurity ions are more closely complexed with the organic phase; the hydrogen peroxide solution is mixed with the sodium hypochlorite solution to increase the pH of the first stripping agent, and the H + The concentration is reduced, making the complex formed by the vanadium extractant and impurities more stable, making it difficult to react with H + At the same time, the existence form of vanadium oxide is changed by oxidation, which reduces the degree of complexation of vanadium with the extraction organic phase, making it easier to fall off from the loaded organic phase, thereby improving the selectivity of vanadium in the vanadium shale acidic leachate, leaving most of the impurity ions in the lean organic phase, and removing more than 95wt% of aluminum, iron and other impurity ions in the vanadium shale acidic leachate. Therefore, the present invention has a good impurity separation effect, and the vanadium electrolyte based on the vanadium shale acidic leachate has a high concentration and high purity.

[0044] The vanadium electrolyte prepared by the present invention based on the vanadium shale acidic leaching solution is tested: the V (IV) concentration is 90-135.0 g / L; the metal impurity ion concentration is much lower than the concentration specified in the first-class product of the national standard (GB / T-37204-2018), among which: Al concentration is ≤5 mg / L, Fe concentration is ≤5 mg / L, Mg concentration is ≤3 mg / L, Na concentration is ≤10 mg / L, K concentration is ≤10 mg / L, and Ca concentration is ≤30 mg / L.

[0045] Therefore, the present invention has the characteristics of low cost, environmental friendliness, simple process, low reagent consumption and energy consumption. The prepared vanadium electrolyte based on vanadium shale acidic leaching solution has high concentration and high purity, and effectively realizes the separation of impurities and the enrichment of vanadium in the vanadium shale acidic leaching solution. Specific implementation methods

[0047] The present invention is further described below in conjunction with specific implementation modes, but is not intended to limit the protection scope thereof.

[0048] A vanadium electrolyte based on vanadium shale acidic leaching solution and a preparation method thereof. The steps of the preparation method described in this specific embodiment are:

[0049] Step 1: Adjust pH

[0050] A pH regulator is added to the vanadium shale acid leaching solution to adjust the pH to 1.8-2.0 to obtain an extraction stock solution.

[0051] The chemical composition of the vanadium shale acid leaching solution is: V is 1600-2000 mg / L, Al is 5000-8000 mg / L, Fe is 5000-8000 mg / L, Mg is 1000-3000 mg / L, Na is 1000-3000 mg / L, K is 1000-3000 mg / L, and Ca is 200-500 mg / L.

[0052] The pH of the vanadium shale acidic leaching solution is 0-1.

[0053] Step 2: Primary extraction and stripping

[0054] Step 2.1, according to the volume ratio of the extracted organic phase to the extracted stock solution of 1: (1 to 3), the extracted organic phase and the extracted stock solution are mixed, and countercurrent extraction is performed at 10 to 50° C. The countercurrent extraction stage is 3 to 6, and the countercurrent extraction time is 8 to 12 min. Phase separation is performed to obtain a raffinate and a loaded organic phase.

[0055] The extraction organic phase is a mixture prepared by mixing 15-30 vol% of vanadium extractant, 5 vol% of tributyl phosphate and 65-80 vol% of sulfonated kerosene.

[0056] Step 2.2, according to the volume ratio of the loaded organic phase to the detergent being 1:(1-3), the loaded organic phase and the detergent are mixed, stirred at 10-30° C. for 10-40 min, and phase separated to obtain washing water and a washed loaded organic phase.

[0057] The detergent is 0.01-0.05 mol / L dilute sulfuric acid or deionized water.

[0058] Step 2.3, according to the volume ratio of the washed loaded organic phase to the first-stage stripping agent of (1-4):1, the washed loaded organic phase is mixed with the first-stage stripping agent, and single-stage stripping is carried out at 40-60°C for 8-12 minutes, and the phases are separated to obtain a first-stage stripping liquid and a first-stage lean organic phase.

[0059] The first-stage stripping agent is a mixture prepared by mixing the sodium hypochlorite solution and the hydrogen peroxide solution according to a volume ratio of sodium hypochlorite solution to hydrogen peroxide solution of (0.081-0.143):1; wherein the mass concentration of the hydrogen peroxide solution is 1.5-6%, and the mass concentration of the sodium hypochlorite is 6-10%.

[0060] Step 3: Reduction and pH adjustment

[0061] Step 3.1, according to the ratio of the amount of reducing agent: vanadium in the first stripping solution of (1.2-2):1; add the reducing agent to the first stripping solution, stir at 10-30° C. for 10-30 minutes, and obtain a reduced stripping solution.

[0062] Step 3.2, adding 3% by volume of dilute sulfuric acid to the reduced stripping solution, adjusting the pH to 1.5-3, and obtaining a vanadium-rich solution after adjusting the pH.

[0063] Step 4: Secondary extraction and stripping

[0064] Step 4.1, according to the volume ratio of the extracted organic phase to the vanadium-rich solution after adjusting the pH being 1: (1-3), the extracted organic phase and the vanadium-rich solution after adjusting the pH are mixed, and countercurrent extraction is performed at 10-50° C., the countercurrent extraction stage is 3-6, the countercurrent extraction time is 8-12 min, and the phases are separated to obtain a raffinate and a loaded organic phase.

[0065] The organic phase extracted in this step is the same as the organic phase extracted in step 2.1.

[0066] Step 4.2, according to the volume ratio of the loaded organic phase to the second-stage stripping agent of (1-8):1, the loaded organic phase and the second-stage stripping agent are mixed, countercurrent stripping is performed at 10-30°C, the countercurrent stripping stage is 3-6, the countercurrent stripping time is 30-50min, and the phases are separated to obtain a second-stage stripping liquid and a second-stage lean organic phase.

[0067] Step 5: Degreasing

[0068] Step 5.1: Deoil the second-stage stripping solution to obtain a vanadium electrolyte V(IV) based on a vanadium shale acidic leaching solution.

[0069] The vanadium electrolyte V(IV): V concentration is 90-135.0 g / L, Al concentration is ≤5 mg / L, Fe concentration is ≤5 mg / L, Mg concentration is ≤3 mg / L, Na concentration is ≤10 mg / L, K concentration is ≤10 mg / L, and Ca concentration is ≤30 mg / L.

[0070] The vanadium shale acidic leaching solution has a valence state of tetravalent vanadium and a valence state of divalent iron.

[0071] The pH adjuster is sodium hydroxide or sodium bicarbonate.

[0072] The vanadium extractant is di(2-ethylhexyl) phosphate or 2-ethylhexylphosphonic acid mono(2-ethylhexyl) ester.

[0073] The reducing agent is one of oxalic acid, ascorbic acid, citric acid and sulfurous acid.

[0074] The second-stage stripping agent is 2-6 mol / L sulfuric acid.

[0075] The oil removal treatment is carried out by using one of clarification tank clarification, resin flotation column adsorption and activated carbon adsorption.

[0076] Example 1

[0077] A vanadium electrolyte based on vanadium shale acidic leaching solution and a preparation method thereof. The steps of the preparation method described in this embodiment are:

[0078] Step 1: Adjust pH

[0079] A pH regulator is added to the vanadium shale acidic leaching solution to adjust the pH to 1.9 to obtain an extraction stock solution.

[0080] The chemical composition of the vanadium shale acidic leaching solution is: V is 1988 mg / L, Al is 5070 mg / L, Fe is 6490 mg / L, Mg is 2986 mg / L, Na is 2293 mg / L, K is 1927 mg / L, and Ca is 458.3 mg / L.

[0081] The pH value of the vanadium shale acidic leaching solution is 0.04.

[0082] Step 2: Primary extraction and stripping

[0083] Step 2.1, according to the volume ratio of the extracted organic phase to the extracted stock solution of 1:2, the extracted organic phase and the extracted stock solution are mixed, and countercurrent extraction is performed at 10°C, the countercurrent extraction stage is 6, the countercurrent extraction time is 8 minutes, and the phases are separated to obtain a raffinate and a loaded organic phase.

[0084] The extraction organic phase is a mixture prepared by mixing 15 vol% of a vanadium extractant, 5 vol% of tributyl phosphate and 80 vol% of sulfonated kerosene.

[0085] Step 2.2, according to the volume ratio of the loaded organic phase to the detergent being 1:1, the loaded organic phase and the detergent are mixed, stirred at 10° C. for 10 min, and phase separated to obtain washing water and a washed loaded organic phase.

[0086] The detergent is deionized water.

[0087] Step 2.3, according to the volume ratio of the washed loaded organic phase to the first-stage stripping agent of 1:1, the washed loaded organic phase and the first-stage stripping agent are mixed, and single-stage stripping is carried out at 40°C for 8 minutes, and the phases are separated to obtain a first-stage stripping liquid and a lean organic phase.

[0088] The first-stage stripping agent is a mixture prepared by mixing the sodium hypochlorite solution and the hydrogen peroxide solution at a volume ratio of 0.081:1; wherein the mass concentration of the hydrogen peroxide solution is 1.5%, and the mass concentration of the sodium hypochlorite is 6%.

[0089] Step 3: Reduction and pH adjustment

[0090] Step 3.1, according to the ratio of the amount of reducing agent to the amount of vanadium in the first stripping solution of 1.2:1; adding the reducing agent to the first stripping solution, stirring at 10° C. for 10 minutes, to obtain a reduced stripping solution.

[0091] Step 3.2, adding 3% by volume of dilute sulfuric acid to the reduced stripping solution, adjusting the pH to 3, and obtaining a vanadium-rich solution after adjusting the pH.

[0092] Step 4: Secondary extraction and stripping

[0093] Step 4.1, according to the volume ratio of the extracted organic phase to the vanadium-rich solution after adjusting the pH being 1:1, the extracted organic phase and the vanadium-rich solution after adjusting the pH are mixed, and countercurrent extraction is performed at 10° C. The countercurrent extraction stage is 3, the countercurrent extraction time is 8 min, and the phases are separated to obtain a raffinate and a loaded organic phase.

[0094] The organic phase extracted in this step is the same as the organic phase extracted in step 2.1.

[0095] Step 4.2, according to the volume ratio of the loaded organic phase to the second-stage stripping agent being 1:1, the loaded organic phase and the second-stage stripping agent are mixed, countercurrent stripping is performed at 10°C, the countercurrent stripping stage is 3, the countercurrent stripping time is 30 minutes, and the phases are separated to obtain a second-stage stripping liquid and a second-stage lean organic phase.

[0096] Step 5: Degreasing

[0097] Step 5.1: Deoil the second-stage stripping solution to obtain a vanadium electrolyte V(IV) based on a vanadium shale acidic leaching solution.

[0098] The vanadium electrolyte V(IV): V concentration is 91.18 g / L, Al concentration is 1.091 mg / L, Fe concentration is 0.782 mg / L, Mg concentration is 0.68 mg / L, Na concentration is 1.791 mg / L, K concentration is 1.03 mg / L, and Ca concentration is 5.21 mg / L.

[0099] The vanadium shale acidic leaching solution has a valence state of tetravalent vanadium and a valence state of divalent iron.

[0100] The pH regulator is sodium hydroxide.

[0101] The vanadium extractant is di(2-ethylhexyl) phosphate.

[0102] The reducing agent is sulfurous acid.

[0103] The second-stage stripping agent is 2 mol / L sulfuric acid.

[0104] The oil removal treatment is carried out by using a clarification tank.

[0105] Example 2

[0106] A vanadium electrolyte based on vanadium shale acidic leaching solution and a preparation method thereof. The steps of the preparation method described in this embodiment are:

[0107] Step 1: Adjust pH

[0108] A pH regulator is added to the vanadium shale acidic leaching solution to adjust the pH to 2.0 to obtain an extraction stock solution.

[0109] The chemical composition of the vanadium shale acidic leaching solution is: V is 1604 mg / L, Al is 7940 mg / L, Fe is 7934 mg / L, Mg is 1534 mg / L, Na is 1052 mg / L, K is 2314 mg / L, and Ca is 324 mg / L.

[0110] The pH value of the vanadium shale acidic leaching solution is 0.4.

[0111] Step 2: Primary extraction and stripping

[0112] Step 2.1, according to the volume ratio of the extracted organic phase to the extracted stock solution of 1:1, the extracted organic phase and the extracted stock solution are mixed, and countercurrent extraction is performed at 25°C, the countercurrent extraction stage is 3, the countercurrent extraction time is 10 min, and the phases are separated to obtain a raffinate and a loaded organic phase.

[0113] The extraction organic phase is a mixture prepared by mixing 20 vol% of vanadium extractant, 5 vol% of tributyl phosphate and 75 ol% of sulfonated kerosene.

[0114] Step 2.2, according to the volume ratio of the loaded organic phase to the detergent being 1:2, the loaded organic phase and the detergent are mixed, stirred at 20° C. for 20 min, and phase separated to obtain washing water and a washed loaded organic phase.

[0115] The detergent is 0.01 mol / L dilute sulfuric acid.

[0116] Step 2.3, according to the volume ratio of the washed loaded organic phase to the first-stage stripping agent of 2:1, the washed loaded organic phase is mixed with the first-stage stripping agent, and single-stage stripping is carried out at 50°C for 10 minutes, and the phases are separated to obtain a first-stage stripping liquid and a lean organic phase.

[0117] The first-stage stripping agent is a mixture prepared by mixing the sodium hypochlorite solution and the hydrogen peroxide solution at a volume ratio of 0.09:1; wherein the mass concentration of the hydrogen peroxide solution is 3%, and the mass concentration of the sodium hypochlorite is 8%.

[0118] Step 3: Reduction and pH adjustment

[0119] Step 3.1, according to the ratio of the amount of reducing agent to the amount of vanadium in the first stripping solution of 1.4:1; adding the reducing agent to the first stripping solution, stirring at 20° C. for 20 minutes, to obtain a reduced stripping solution.

[0120] Step 3.2, adding 3% by volume of dilute sulfuric acid to the reduced stripping solution, adjusting the pH to 1.5, and obtaining a vanadium-rich solution after adjusting the pH.

[0121] Step 4: Secondary extraction and stripping

[0122] Step 4.1, according to the volume ratio of the extracted organic phase to the vanadium-rich solution after adjusting the pH being 1:2, the extracted organic phase and the vanadium-rich solution after adjusting the pH are mixed, and countercurrent extraction is performed at 20° C. The countercurrent extraction stage is 5 and the countercurrent extraction time is 9 minutes. Phase separation is performed to obtain a raffinate and a loaded organic phase.

[0123] The organic phase extracted in this step is the same as the organic phase extracted in step 2.1.

[0124] Step 4.2, according to the volume ratio of the loaded organic phase to the second-stage stripping agent of 3:1, the loaded organic phase and the second-stage stripping agent are mixed, countercurrent stripping is performed at 20°C, the countercurrent stripping stage is 5, the countercurrent stripping time is 35min, and the phases are separated to obtain the second-stage stripping liquid and the second-stage lean organic phase.

[0125] Step 5: Degreasing

[0126] Step 5.1: Deoil the second-stage stripping solution to obtain a vanadium electrolyte V(IV) based on a vanadium shale acidic leaching solution.

[0127] The vanadium electrolyte V(IV): V concentration is 134.7 g / L, Al concentration is 4.98 mg / L, Fe concentration is 1.573 mg / L, Mg concentration is 1.32 mg / L, Na concentration is 3.68 mg / L, K concentration is 3.951 mg / L, and Ca concentration is 13.73 mg / L.

[0128] The vanadium shale acidic leaching solution has a valence state of tetravalent vanadium and a valence state of divalent iron.

[0129] The pH regulator is sodium hydroxide.

[0130] The vanadium extractant is di(2-ethylhexyl) phosphate.

[0131] The reducing agent is ascorbic acid.

[0132] The second-stage stripping agent is 3 mol / L sulfuric acid.

[0133] The oil removal treatment is carried out by activated carbon adsorption.

[0134] Example 3

[0135] A vanadium electrolyte based on vanadium shale acidic leaching solution and a preparation method thereof. The steps of the preparation method described in this embodiment are:

[0136] Step 1: Adjust pH

[0137] A pH regulator is added to the vanadium shale acidic leaching solution to adjust the pH to 1.8 to obtain an extraction stock solution.

[0138] The chemical composition of the vanadium shale acid leaching solution is: V is 1735 mg / L, Al is 6535 mg / L, Fe is 5032 mg / L, Mg is 1043 mg / L, Na is 1823 mg / L, K is 1009 mg / L, and Ca is 201 mg / L.

[0139] The pH value of the vanadium shale acidic leaching solution is 0.8.

[0140] Step 2: Primary extraction and stripping

[0141] Step 2.1, according to the volume ratio of the extracted organic phase to the extracted stock solution of 1:3, the extracted organic phase and the extracted stock solution are mixed, and countercurrent extraction is performed at 30°C, the countercurrent extraction stage is 5, the countercurrent extraction time is 12 minutes, and the phases are separated to obtain a raffinate and a loaded organic phase.

[0142] The extraction organic phase is a mixture prepared by mixing 25 vol% of a vanadium extractant, 5 vol% of tributyl phosphate and 70 vol% of sulfonated kerosene.

[0143] Step 2.2, according to the volume ratio of the loaded organic phase to the detergent being 1:3, the loaded organic phase and the detergent are mixed, stirred at 25° C. for 30 min, and phase separated to obtain washing water and a washed loaded organic phase.

[0144] The detergent is 0.03 mol / L dilute sulfuric acid.

[0145] Step 2.3, according to the volume ratio of the washed loaded organic phase to the first-stage stripping agent of 3:1, the washed loaded organic phase and the first-stage stripping agent are mixed, and single-stage stripping is carried out at 55°C for 12 minutes, and the phases are separated to obtain a first-stage stripping liquid and a lean organic phase.

[0146] The first-stage stripping agent is a mixture prepared by mixing the sodium hypochlorite solution and the hydrogen peroxide solution at a volume ratio of 0.143:1; wherein the mass concentration of the hydrogen peroxide solution is 4.5%, and the mass concentration of the sodium hypochlorite is 10%.

[0147] Step 3: Reduction and pH adjustment

[0148] Step 3.1, according to the ratio of the amount of reducing agent to the amount of vanadium in the first stripping solution of 1.7:1; adding the reducing agent to the first stripping solution, stirring at 25° C. for 25 minutes, to obtain a reduced stripping solution.

[0149] Step 3.2, adding 3% by volume of dilute sulfuric acid to the reduced stripping solution, adjusting the pH to 2.5, and obtaining a vanadium-rich solution after adjusting the pH.

[0150] Step 4: Secondary extraction and stripping

[0151] Step 4.1, according to the volume ratio of the extracted organic phase to the vanadium-rich solution after adjusting the pH being 1:3, the extracted organic phase and the vanadium-rich solution after adjusting the pH are mixed, and countercurrent extraction is performed at 40° C. The countercurrent extraction stage is 4, the countercurrent extraction time is 12 min, and the phases are separated to obtain a raffinate and a loaded organic phase.

[0152] The organic phase extracted in this step is the same as the organic phase extracted in step 2.1.

[0153] Step 4.2, according to the volume ratio of the loaded organic phase to the second-stage stripping agent of 5:1, the loaded organic phase and the second-stage stripping agent are mixed, countercurrent stripping is performed at 25°C, the countercurrent stripping stage is 4, the countercurrent stripping time is 40min, and the phases are separated to obtain the second-stage stripping liquid and the second-stage lean organic phase.

[0154] Step 5: Degreasing

[0155] Step 5.1: Deoil the second-stage stripping solution to obtain a vanadium electrolyte V(IV) based on a vanadium shale acidic leaching solution.

[0156] The vanadium electrolyte V(IV): V concentration is 118.56 g / L, Al concentration is 2.78 mg / L, Fe concentration is 2.898 mg / L, Mg concentration is 1.962 mg / L, Na concentration is 6.63 mg / L, K concentration is 6.342 mg / L, and Ca concentration is 22.327 mg / L.

[0157] The vanadium shale acidic leaching solution has a valence state of tetravalent vanadium and a valence state of divalent iron.

[0158] The pH regulator is sodium hydroxide.

[0159] The vanadium extractant is 2-ethylhexylphosphonic acid mono(2-ethylhexyl) ester.

[0160] The reducing agent is oxalic acid.

[0161] The second-stage stripping agent is 5 mol / L sulfuric acid.

[0162] The oil removal treatment is carried out by activated carbon adsorption.

[0163] Example 4

[0164] A vanadium electrolyte based on vanadium shale acidic leaching solution and a preparation method thereof. The steps of the preparation method described in this embodiment are:

[0165] Step 1: Adjust pH

[0166] A pH regulator is added to the vanadium shale acid leaching solution to adjust the pH to 1.8-2.0 to obtain an extraction stock solution.

[0167] The chemical composition of the vanadium shale acidic leaching solution is: V is 1845 mg / L, Al is 7121 mg / L, Fe is 5941 mg / L, Mg is 2367 mg / L, Na is 2921 mg / L, K is 2986 mg / L, and Ca is 498.4 mg / L.

[0168] The pH of the vanadium shale acidic leaching solution is 1.0.

[0169] Step 2: Primary extraction and stripping

[0170] Step 2.1, according to the volume ratio of the extracted organic phase to the extracted stock solution of 1:2.5, the extracted organic phase and the extracted stock solution are mixed, and countercurrent extraction is performed at 50°C, the countercurrent extraction stage is 4, the countercurrent extraction time is 9 minutes, and the phases are separated to obtain a raffinate and a loaded organic phase.

[0171] The extraction organic phase is a mixture prepared by mixing 30 vol% of a vanadium extractant, 5 vol% of tributyl phosphate and 65 vol% of sulfonated kerosene.

[0172] Step 2.2, according to the volume ratio of the loaded organic phase to the detergent being 1:3, the loaded organic phase and the detergent are mixed, stirred at 30° C. for 40 min, and phase separated to obtain washing water and a washed loaded organic phase.

[0173] The detergent is 0.05 mol / L dilute sulfuric acid.

[0174] Step 2.3, according to the volume ratio of the washed loaded organic phase to the first-stage stripping agent of 4:1, the washed loaded organic phase is mixed with the first-stage stripping agent, and single-stage stripping is carried out at 60°C for 11 minutes, and the phases are separated to obtain a first-stage stripping liquid and a lean organic phase.

[0175] The first-stage stripping agent is a mixture prepared by mixing the sodium hypochlorite solution and the hydrogen peroxide solution at a volume ratio of 0.112:1; wherein the mass concentration of the hydrogen peroxide solution is 6%, and the mass concentration of the sodium hypochlorite is 9%.

[0176] Step 3: Reduction and pH adjustment

[0177] Step 3.1, according to the ratio of the amount of reducing agent to the amount of vanadium in the first stripping solution of 2:1; adding the reducing agent to the first stripping solution, stirring at 30° C. for 30 minutes, to obtain a reduced stripping solution.

[0178] Step 3.2, adding 3% by volume of dilute sulfuric acid to the reduced stripping solution, adjusting the pH to 2, and obtaining a vanadium-rich solution after adjusting the pH.

[0179] Step 4: Secondary extraction and stripping

[0180] Step 4.1, according to the volume ratio of the extracted organic phase to the vanadium-rich solution after adjusting the pH being 1:2.5, the extracted organic phase and the vanadium-rich solution after adjusting the pH are mixed, and countercurrent extraction is performed at 50° C. The countercurrent extraction stage is 6 and the countercurrent extraction time is 10 min. Phase separation is performed to obtain a raffinate and a loaded organic phase.

[0181] The organic phase extracted in this step is the same as the organic phase extracted in step 2.1.

[0182] Step 4.2, according to the volume ratio of the loaded organic phase to the second-stage stripping agent being 8:1, the loaded organic phase and the second-stage stripping agent are mixed, countercurrent stripping is performed at 30°C, the countercurrent stripping stage is 6, the countercurrent stripping time is 50min, and the phases are separated to obtain a second-stage stripping liquid and a second-stage lean organic phase.

[0183] Step 5: Degreasing

[0184] Step 5.1: Deoil the second-stage stripping solution to obtain a vanadium electrolyte V(IV) based on a vanadium shale acidic leaching solution.

[0185] The vanadium electrolyte V(IV): V concentration is 109.44 g / L, Al concentration is 4.52 mg / L, Fe concentration is 4.963 mg / L, Mg concentration is 2.965 mg / L, Na concentration is 9.812 mg / L, K concentration is 9.963 mg / L, and Ca concentration is 29.823 mg / L.

[0186] The vanadium shale acidic leaching solution has a valence state of tetravalent vanadium and a valence state of divalent iron.

[0187] The pH regulator is sodium bicarbonate.

[0188] The vanadium extractant is 2-ethylhexylphosphonic acid mono(2-ethylhexyl) ester.

[0189] The reducing agent is citric acid.

[0190] The second-stage stripping agent is 6 mol / L sulfuric acid.

[0191] The oil removal treatment is carried out by using resin flotation column adsorption.

[0192] Compared with the prior art, this specific implementation has the following beneficial effects:

[0193] 1. This specific implementation method has low preparation cost, clean and efficient, simple process, less pharmaceutical consumables and low energy consumption.

[0194] This specific implementation method uses vanadium shale acid leachate as raw material, and realizes the preparation of vanadium electrolyte based on vanadium shale acid leachate through "pretreatment-one-stage extraction-reduction-two-stage extraction". Compared with the existing "extraction-oxidation-vanadium precipitation-alkali dissolution-vanadium precipitation-calcination-reduction and dissolution in sulfuric acid" process, it reduces oxidation, multiple vanadium precipitation, alkali dissolution, and high-temperature calcination, avoids the use of a large number of reagents and high-temperature reactions, thereby reducing the cost of reagent consumables and streamlining the process. Therefore, this specific implementation method has less reagent consumables, low energy consumption, low preparation cost, short process flow, and clean and efficient.

[0195] 2. This specific implementation method has good impurity separation effect, high electrolyte concentration and high purity

[0196] In this specific embodiment, hydrogen peroxide solution and sodium hypochlorite solution are used for oxidative stripping to oxidize vanadium (IV) and iron (II) in the vanadium shale acidic leachate to vanadium (V) and iron (III), respectively, and the high-valent impurity ions are more closely complexed with the organic phase; the hydrogen peroxide solution is mixed with the sodium hypochlorite solution to increase the pH of the first stripping agent, H + The concentration is reduced, making the complex formed by the vanadium extractant and impurities more stable, making it difficult to react with H + At the same time, the existence form of vanadium oxide is changed by oxidation, which reduces the degree of complexation of vanadium with the extraction organic phase, making it easier to fall off from the loaded organic phase, thereby improving the selectivity of vanadium in the vanadium shale acidic leachate, leaving most of the impurity ions in the lean organic phase, and removing more than 95wt% of aluminum, iron and other impurity ions in the vanadium shale acidic leachate. Therefore, the impurity separation effect of this specific embodiment is good, and the vanadium electrolyte based on the vanadium shale acidic leachate is high in concentration and purity.

[0197] The vanadium electrolyte based on vanadium shale acidic leaching solution prepared in this specific embodiment is tested: the V (IV) concentration is 90-135.0 g / L; the concentration of metal impurity ions is much lower than the concentration specified in the first-class national standard (GB / T-37204-2018), among which: Al concentration ≤5 mg / L, Fe concentration ≤5 mg / L, Mg concentration ≤3 mg / L, Na concentration ≤10 mg / L, K concentration ≤10 mg / L, Ca concentration ≤30 mg / L.

[0198] Therefore, this specific embodiment has the characteristics of low cost, environmental friendliness, simple process, low reagent consumption and energy consumption. The prepared vanadium electrolyte based on vanadium shale acidic leaching solution has high concentration and high purity, and effectively realizes the separation of impurities and the enrichment of vanadium in the vanadium shale acidic leaching solution.

Claims

1. A method for preparing a vanadium electrolyte based on vanadium shale acidic leaching solution, characterized in that The steps of the preparation method are: Step 1: Adjust pH Adding a pH regulator to the vanadium shale acidic leaching solution to adjust the pH to 1.8-2.0 to obtain an extraction stock solution; The chemical composition of the vanadium shale acidic leaching solution is: V is 1600-2000 mg / L, Al is 5000-8000 mg / L, Fe is 5000-8000 mg / L, Mg is 1000-3000 mg / L, Na is 1000-3000 mg / L, K is 1000-3000 mg / L, and Ca is 200-500 mg / L; The pH of the vanadium shale acidic leaching solution is 0-1; Step 2: Primary extraction and stripping Step 2.1, according to the volume ratio of the extracted organic phase to the extracted stock solution of 1: (1-3), the extracted organic phase and the extracted stock solution are mixed, and countercurrent extraction is performed at 10-50° C., the countercurrent extraction stage is 3-6 stages, the countercurrent extraction time is 8-12 min, and phase separation is performed to obtain a raffinate and a loaded organic phase; The extraction organic phase is a mixture prepared by mixing 15-30 vol% of a vanadium extractant, 5 vol% of tributyl phosphate and 65-80 vol% of sulfonated kerosene; Step 2.2, according to the volume ratio of the loaded organic phase to the detergent being 1:(1-3), the loaded organic phase and the detergent are mixed, stirred at 10-30° C. for 10-40 min, and phase separated to obtain washing water and a washed loaded organic phase; The detergent is 0.01-0.05 mol / L dilute sulfuric acid or deionized water; Step 2.3, according to the volume ratio of the washed loaded organic phase to the first stripping agent of (1-4):1, the washed loaded organic phase and the first stripping agent are mixed, and single-stage stripping is performed at 40-60° C. The single-stage stripping time is 8-12 min, and phases are separated to obtain a first stripping solution and a lean organic phase; The first-stage stripping agent is a mixture prepared by mixing the sodium hypochlorite solution and the hydrogen peroxide solution in a volume ratio of sodium hypochlorite solution to hydrogen peroxide solution of (0.081-0.143):1; wherein the mass concentration of the hydrogen peroxide solution is 1.5-6%, and the mass concentration of the sodium hypochlorite is 6-10%; Step 3: Reduction and pH adjustment Step 3.1, according to the ratio of the amount of reducing agent to the amount of vanadium in the first stripping solution of (1.2-2):1; adding the reducing agent to the first stripping solution, stirring at 10-30° C. for 10-30 minutes, to obtain a reduced stripping solution; Step 3.2, adding 3% by volume of dilute sulfuric acid to the reduced stripping solution, adjusting the pH to 1.5-3, and obtaining a vanadium-rich solution after adjusting the pH; Step 4: Secondary extraction and stripping Step 4.1, according to the volume ratio of the extracted organic phase to the vanadium-rich solution after adjusting the pH being 1: (1-3), the extracted organic phase and the vanadium-rich solution after adjusting the pH are mixed, and countercurrent extraction is performed at 10-50° C., the countercurrent extraction stage is 3-6, the countercurrent extraction time is 8-12 min, and the phases are separated to obtain a raffinate and a loaded organic phase; The organic phase extracted in this step is the same as the organic phase extracted in step 2.1; Step 4.2, according to the volume ratio of the loaded organic phase to the second-stage stripping agent being (1-8):1, the loaded organic phase and the second-stage stripping agent are mixed, countercurrent stripping is performed at 10-30°C, the countercurrent stripping stage is 3-6, the countercurrent stripping time is 30-50min, and phase separation is performed to obtain a second-stage stripping liquid and a second-stage lean organic phase; Step 5: Degreasing Step 5.1, deoiling the second-stage stripping solution to obtain a vanadium electrolyte V(IV) based on a vanadium shale acidic leaching solution; The vanadium electrolyte V(IV): V concentration is 90-135.0 g / L, Al concentration is ≤5 mg / L, Fe concentration is ≤5 mg / L, Mg concentration is ≤3 mg / L, Na concentration is ≤10 mg / L, K concentration is ≤10 mg / L, and Ca concentration is ≤30 mg / L.

2. The method for preparing a vanadium electrolyte based on a vanadium shale acidic leaching solution according to claim 1, characterized in that The vanadium shale acidic leaching solution has a valence state of tetravalent vanadium and a valence state of divalent iron.

3. The method for preparing a vanadium electrolyte based on a vanadium shale acidic leaching solution according to claim 1, characterized in that The pH adjuster is sodium hydroxide or sodium bicarbonate.

4. The method for preparing a vanadium electrolyte based on a vanadium shale acidic leaching solution according to claim 1, characterized in that The vanadium extractant is di(2-ethylhexyl) phosphate or 2-ethylhexylphosphonic acid mono(2-ethylhexyl) ester.

5. The method for preparing a vanadium electrolyte based on vanadium shale acidic leaching solution according to claim 1, characterized in that The reducing agent is one of oxalic acid, ascorbic acid, citric acid and sulfurous acid.

6. The method for preparing a vanadium electrolyte based on a vanadium shale acidic leaching solution according to claim 1, characterized in that The second-stage stripping agent is 2-6 mol / L sulfuric acid.

7. The method for preparing a vanadium electrolyte based on vanadium shale acidic leaching solution according to claim 1, characterized in that The oil removal treatment is carried out by using one of clarification tank clarification, resin flotation column adsorption and activated carbon adsorption.

8. A vanadium electrolyte based on vanadium shale acidic leaching solution, characterized in that The vanadium electrolyte based on vanadium shale acidic leaching solution is a vanadium electrolyte based on vanadium shale acidic leaching solution prepared by the method for preparing a vanadium electrolyte based on vanadium shale acidic leaching solution according to any one of claims 1 to 7.