A method for preparing high-purity vanadium products based on electrochemical vanadium precipitation

Abstract

The present invention relates to technologies related to vanadium metallurgy and vanadium purification, specifically a method for preparing high-purity vanadium products based on electrochemical vanadium precipitation, which breaks through the problems existing in traditional industrial production of products such as high-purity vanadium pentoxide, including high cost, low efficiency, and serious environmental pollution. Specifically, using a vanadium-containing leaching solution as a raw material, through the method of electrochemical electrolysis, the instantaneous pH value on the electrode surface is regulated, so that vanadium pentoxide compounds achieve vanadium precipitation at a controllable speed within the confined area of the electrode surface interface, avoiding the co-deposition of impurity ions. After the vanadium deposit is fully washed and then redissolved into a specific aqueous phase, secondary electrolytic vanadium precipitation is carried out. The vanadium precipitate can be directly acid-dissolved to prepare vanadium battery electrolyte, or high-purity vanadium pentoxide can be prepared after sintering. This process directly simplifies the current multi-step process of chemical vanadium precipitation and dissolution for traditional high-purity vanadium purification, thereby reducing the process cost. The method of the present invention is simple, easy to operate, and the raw materials are easily available, suitable for large-scale industrial production.

Description

Technical Field

[0001] The present invention relates to technologies related to vanadium metallurgy and vanadium purification, and specifically to a method for preparing high-purity vanadium products based on electrochemical vanadium precipitation. Background Art

[0002] High-purity vanadium products (such as vanadium pentoxide with a purity greater than 99.9 wt%) have high added value and are widely used in fields such as metallurgy, chemical industry, atomic energy, and aviation. The demand for high-purity vanadium products in strategic emerging industries such as all-vanadium redox flow batteries for large-scale energy storage, lithium vanadate-based lithium-ion batteries, and advanced vanadium-based alloys is increasing strongly. In the production of high-purity vanadium products, vanadium precipitation from vanadium-containing leaching solutions is a key step in purification, and the purity of the vanadium deposit directly determines the cost of subsequent processes and the purity of the finished product. However, in traditional chemical vanadium precipitation processes, the deposition rate is too fast, resulting in impurity ions being incorporated into the deposit, and the purity of the vanadium deposit is low. Multiple stages of vanadium precipitation or multiple extractions are required subsequently to obtain high-purity vanadium products, the process is complex and costly, and the environmental pollution is large.

[0003] Therefore, developing a simple, efficient, low-cost, and environmentally friendly vanadium extraction process will greatly solve the technical limitations of high-purity vanadium products in terms of cost and environmental protection, not only creating huge economic benefits but also bringing significant social benefits. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for precipitating and purifying vanadium by electrochemical means to prepare high-purity vanadium pentoxide, so as to solve the problems such as complex process, high cost, and large environmental pollution in the industrial production of high-purity vanadium products.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] A method for preparing high-purity vanadium products based on electrochemical vanadium precipitation uses a vanadium-containing leaching solution as a raw material, performs vanadium precipitation by electrochemical electrolysis, filters the vanadium deposit, fully washes it and then redissolves it, and performs secondary electrochemical electrolysis for vanadium precipitation; the secondary vanadium deposit is acid-dissolved to directly prepare a vanadium battery electrolyte, or directly sintered to prepare high-purity vanadium pentoxide.

[0007] In the method for preparing high-purity vanadium products based on electrochemical vanadium precipitation, the vanadium-containing leaching solution is the leaching solution generated by traditional vanadium extraction processes, including vanadium-containing leaching solutions generated from low-vanadium steel slag vanadium extraction, stone coal vanadium extraction, waste catalyst vanadium extraction, petroleum coke vanadium extraction, or petroleum ash vanadium extraction, and the vanadium content of the vanadium-containing leaching solution is 1 g / L to 200 g / L.

[0008] In the method for preparing high-purity vanadium products based on electrochemical vanadium precipitation, the adopted electrochemical electrolysis method includes constant current electrolysis, constant voltage electrolysis, or constant current pulse electrolysis, and the electrolysis device uses a single-chamber electrolytic cell or a two-chamber electrolytic cell.

[0009] In the method for producing high-purity vanadium products based on electrochemical vanadium precipitation, when using a single-chamber electrolytic cell for electrolysis, the area ratio of the positive electrode to the negative electrode is 1:10 to 10:1, and the distance between the positive and negative electrodes is 1 mm to 100 mm; when using a two-chamber electrolytic cell for electrolysis, the area ratio of the positive electrode to the negative electrode is 1:5 to 5:1, the distance between the positive and negative electrodes is 5 mm to 50 mm, and a diaphragm is installed between the positive and negative electrodes.

[0010] In the method for producing high-purity vanadium products based on electrochemical vanadium precipitation, the positive electrode is a dimensionally stable electrode, specifically one of a boron-doped diamond thin film electrode, a titanium-based ruthenium-iridium electrode, a titanium-based iridium-tantalum electrode, a titanium-based ruthenium-indium-tin electrode, a titanium-based tin-antimony oxide electrode, a titanium-based sub-titanium oxide electrode, and a titanium-based lead dioxide electrode;

[0011] The negative electrode material includes at least one of a metal material and a carbon material, where: the metal material includes at least one of stainless steel, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, niobium, tantalum, zirconium, tungsten, cerium, aluminum, bismuth, rhenium, barium, osmium, tin, lead, gold, silver, platinum, palladium, iridium, rhodium, molybdenum, and ruthenium; the carbon material includes any one of graphite felt, carbon felt, graphite, glassy carbon, boron-doped diamond, activated carbon, graphene, carbon fiber, carbon nanotube, and carbon sponge;

[0012] The shape of the electrode includes any one of sheet, rod, wire, granular, sponge-like, mesh-like, and porous structures.

[0013] In the method for producing high-purity vanadium products based on electrochemical vanadium precipitation, when using a two-chamber electrolytic cell for electrolysis, the diaphragm is one of the diaphragms made of polybenzothiazole, polybenzimidazole, sulfonated sulfonated polyethylene, polyethersulfone, sulfonated polypropylene, polyimide, polysulfone, perfluorosulfonic acid resin, polyetheretherketone, perfluorocarboxylic acid resin, and polyvinylidene fluoride resin. The perfluorosulfonic acid resin uses the Nafion series perfluorosulfonic acid membranes of DuPont Company, including Nafion212, Nafion115, Nafion211, or Nafion117.

[0014] In the method for producing high-purity vanadium products based on electrochemical vanadium precipitation, when using constant current electrolysis, the current density range is 10 mA / cm 2 ~1000 mA / cm 2 , the electrolysis time is 0.5 to 10 h, and the electrolysis temperature is 25 °C to 70 °C; when using constant voltage electrolysis, the voltage range is 1 V to 50 V, the electrolysis time is 0.5 to 10 h, and the electrolysis temperature is 25 °C to 70 °C; when using constant current pulse electrolysis, the current density range is 10 mA / cm 2 ~1000 mA / cm 2 , the electrolysis time is 0.5 to 10 h, the frequency is 200 to 2000 Hz, the duty cycle is 20% to 80%, and the electrolysis temperature is 25 °C to 70 °C.

[0015] The method for preparing high-purity vanadium products based on electrochemical vanadium precipitation, the substances for washing the vanadium deposit include one or more of the following: water, ethanol, methanol, acetone, ethyl acetate, toluene, glycerol, white oil.

[0016] The method for preparing high-purity vanadium products based on electrochemical vanadium precipitation, the substances for redissolving the vanadium deposit after cleaning include one or more of the following: water, ethylenediamine, ammonia water, hydrogen peroxide, sodium hypochlorite, triethanolamine, urea, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, hydroxyethylethylenediaminetriacetic acid, nitrilotriacetic acid, hydroxyethylethylenediphosphonic acid, aminotrimethylenephosphonic acid, ethylenediaminetetramethylenephosphonic acid, diethylenetriaminepentamethylenephosphonic acid, triethylenetetraminehexamethylenephosphonic acid, polyaminopolyethermethylenephosphonic acid.

[0017] The method for preparing high-purity vanadium products based on electrochemical vanadium precipitation, for the deposit obtained by secondary electrochemical electrolysis for vanadium precipitation, the vanadium battery electrolyte is prepared by acid dissolution, and the acids used include one or more of the following: hydrochloric acid, sulfuric acid, nitric acid, sulfamic acid, formic acid, acetic acid; for the deposit obtained by secondary electrochemical electrolysis for vanadium precipitation, vanadium pentoxide is prepared by sintering, the sintering temperature is 450°C to 1200°C, and the time is 0.5 h to 10 h.

[0018] The design concept of the present invention is:

[0019] Utilize the strong polarization effect of electrochemistry to rapidly change the pH value in the surface area of the electrode, and achieve rapid vanadium precipitation on the electrode surface to avoid impurity inclusion. Specifically: using the vanadium-containing leaching solution as the raw material, through the way of electrochemical electrolysis, regulate the instantaneous pH value on the electrode surface, so that the pentavalent vanadium compound realizes controllable-speed vanadium precipitation in the electrode surface interface confinement area, avoiding the co-deposition of impurity ions. After the vanadium deposit is fully washed and redissolved into a specific aqueous phase, secondary electrolytic vanadium precipitation is carried out. The vanadium precipitate can be directly acid-dissolved to prepare the vanadium battery electrolyte, or can be sintered to prepare high-purity vanadium pentoxide. This process directly simplifies the current traditional multi-step process of chemical vanadium precipitation - dissolution for high-purity vanadium purification, and breaks through the problems of high cost, low efficiency, and large environmental pollution existing in the traditional industrial production of high-purity products such as vanadium pentoxide.

[0020] The advantages and beneficial effects of the present invention are:

[0021] 1. The process method of the present invention is simple, easy to operate, and the raw materials are easily available.

[0022] 2. The present invention has low input cost and is suitable for large-scale industrial production.

[0023] 3. The vanadium products prepared by the present invention have high purity and good stability.

[0024] 4. The implementation of the present invention plays an important leading role in the low-cost green preparation of high-value-added vanadium products in China, the technological upgrading of the vanadium industry, and the development of all-vanadium redox flow batteries. Detailed implementation mode

[0025] In the specific implementation process, the present invention uses a vanadium-containing leaching solution as a raw material, conducts vanadium precipitation through an electrochemical electrolysis method, then filters the vanadium deposit, performs reverse dissolution after sufficient washing, and conducts secondary electrochemical electrolysis vanadium precipitation. The secondary vanadium deposit can be directly acid-dissolved to prepare a vanadium battery electrolyte, or directly sintered to produce high-purity vanadium pentoxide.

[0026] Next, the present invention will be further elaborated in detail through examples.

[0027] Example 1

[0028] Take 500 ml of the leaching solution obtained from extracting vanadium from low-vanadium steel slag, measure its vanadium content to be 40 g / L (calculated as V2O5), perform constant-current electrolysis in a single-chamber electrolytic cell, with the positive electrode being a boron-doped diamond (BDD) thin-film electrode and the negative electrode being a stainless-steel plate, the current density is 300 mA / cm 2 , the area ratio of the positive and negative electrodes is 1:1, the distance between the positive and negative electrodes is 12 mm, the electrolysis time is 1 h, the constant-temperature temperature of the electrolyte is 25 °C, the electrolyte is stirred forward at a speed of 1000 rpm. The vanadium precipitate on the positive electrode is filtered and washed thoroughly, then reverse-dissolved with a saturated urea solution, and secondary constant-voltage electrolysis is carried out in a single-chamber electrolytic cell. The electrolysis voltage is 15 V, the area ratio of the positive and negative electrodes is 1:1, the distance between the positive and negative electrodes is 12 mm, the electrolysis time is 1 h, the constant-temperature temperature of the electrolyte is 25 °C. The secondary vanadium deposit on the positive electrode is filtered and washed thoroughly, sintered at 800 °C for 2 h, obtaining 18.5 g of vanadium pentoxide, with a recovery rate of 92.5%, and its purity is measured to be greater than 99.5 wt%.

[0029] Example 2

[0030] Take 500 ml of the leaching solution obtained from extracting vanadium from stone coal, measure its vanadium content to be 20 g / L (calculated as V2O5), perform constant-current electrolysis in a single-chamber electrolytic cell, with the positive electrode being a titanium-based ruthenium-iridium electrode and the negative electrode being a graphite felt, the current density is 400 mA / cm 2 , the area ratio of the positive and negative electrodes is 1:2, the distance between the positive and negative electrodes is 10 mm, the electrolysis time is 1.5 h, the constant-temperature temperature of the electrolyte is 35 °C, the electrolyte is stirred forward at a speed of 500 rpm. The vanadium precipitate on the positive electrode is filtered and washed thoroughly, then reverse-dissolved with a triethylenetetramine hexamethylenephosphonic acid solution, and secondary constant-voltage electrolysis is carried out in a single-chamber electrolytic cell. The electrolysis voltage is 10 V, the area ratio of the positive and negative electrodes is 1:2, the distance between the positive and negative electrodes is 10 mm, the electrolysis time is 1.5 h, the constant-temperature temperature of the electrolyte is 35 °C. The secondary vanadium deposit on the positive electrode is filtered and washed thoroughly, sintered at 900 °C for 1.5 h, obtaining 9.5 g of vanadium pentoxide, with a recovery rate of 95%, and its purity is measured to be greater than 99.5 wt%.

[0031] Example 3

[0032] Take 500 ml of the leaching solution for vanadium extraction from waste catalyst, and measure its vanadium content to be 15 g / L (calculated as V2O5). Electrolysate at a constant voltage in a single-chamber electrolytic cell. The positive electrode is a titanium-based iridium-tantalum electrode, the negative electrode is a carbon felt, the voltage is 20 V, the area ratio of the positive and negative electrodes is 2:1, the distance between the positive and negative electrodes is 20 mm, the electrolysis time is 2 h, the constant temperature of the electrolyte is 55 °C, and the electrolyte is stirred forward at a speed of 900 rpm. The vanadium deposition on the positive electrode is filtered and washed thoroughly, and then redissolved with an aminotrimethylenephosphonic acid solution. Secondary constant-current electrolysis is carried out in a single-chamber electrolytic cell, and the current density is 400 mA / cm 2 , the area ratio of the positive and negative electrodes is 2:1, the distance between the positive and negative electrodes is 20 mm, the electrolysis time is 1.6 h, the constant temperature of the electrolyte is 55 °C. The secondary vanadium deposit on the positive electrode is filtered and washed thoroughly, and sintered at 950 °C for 1.5 h to obtain 7.2 g of vanadium pentoxide, with a recovery rate of 96%, and its purity is measured to be greater than 99.5 wt%.

[0033] Example 4

[0034] Take 500 ml of the leaching solution for vanadium extraction from petroleum coke (ash), and measure its vanadium content to be 25 g / L (calculated as V2O5). Electrolysate at a constant voltage in a two-chamber electrolytic cell. The positive electrode is a titanium-based ruthenium-indium-tin electrode, the negative electrode is graphite, and a Nafion 212 perfluorosulfonic acid resin membrane is used as the diaphragm. The voltage is 50 V, the area ratio of the positive and negative electrodes is 3:4, the distance between the positive and negative electrodes is 30 mm, the electrolysis time is 1.6 h, the constant temperature of the electrolyte is 65 °C, and the electrolyte is stirred backward at a speed of 500 rpm. The vanadium deposition on the positive electrode is filtered and washed thoroughly, and then redissolved with a triethanolamine solution. Secondary constant-current electrolysis is carried out in a two-chamber electrolytic cell, and the current density is 200 mA / cm 2 , the area ratio of the positive and negative electrodes is 3:4, the distance between the positive and negative electrodes is 20 mm, the electrolysis time is 4 h, the constant temperature of the electrolyte is 65 °C. The secondary vanadium deposit on the positive electrode is filtered and washed thoroughly, and sintered at 850 °C for 2.5 h to obtain 12 g of vanadium pentoxide, with a recovery rate of 96%, and its purity is measured to be greater than 99.5 wt%.

[0035] Example 5

[0036] Take 500 ml of the leaching solution for vanadium extraction from low-vanadium steel slag, and measure its vanadium content to be 35 g / L (calculated as V2O5). Electrolysate with constant-current pulse in a two-chamber electrolytic cell. The positive electrode is a titanium-based titanium suboxide electrode, the negative electrode is carbon fiber, and a polybenzimidazole resin membrane is used as the diaphragm. The area ratio of the positive and negative electrodes is 4:3, the distance between the positive and negative electrodes is 30 mm, and the current density is 900 mA / cm 2, the electrolysis time was 1 h, the frequency was 1000 Hz, the duty cycle was 50%, and the electrolysis temperature was 70 °C. The electrolyte was stirred in the reverse direction at a speed of 700 rpm. The vanadium precipitation on the positive electrode was filtered and thoroughly washed, then redissolved with an ammonia water solution, and secondary constant-current electrolysis was carried out in a two-chamber electrolytic cell with a current density of 500 mA / cm 2 , the area ratio of the positive and negative electrodes was 4:3, the distance between the positive and negative electrodes was 30 mm, the electrolysis time was 1.2 h, the electrolysis temperature was 70 °C. The secondary vanadium deposit on the positive electrode was filtered and thoroughly washed, and then sintered at 1000 °C for 1 h to obtain 17 g of vanadium pentoxide with a recovery rate of 97.1%, and its purity was measured to be greater than 99.5 wt%.

[0037] Example 6

[0038] Take 500 ml of the leaching solution for vanadium extraction from petroleum coke (ash), and measure its vanadium content to be 12 g / L (calculated as V2O5). Carry out constant-current pulse electrolysis in a two-chamber electrolytic cell. The positive electrode is a titanium-based lead dioxide electrode, the negative electrode is glassy carbon, and the polyether ether ketone resin membrane is used as the diaphragm. The area ratio of the positive and negative electrodes is 5:3, the distance between the positive and negative electrodes is 40 mm, and the current density is 1000 mA / cm 2 , the electrolysis time was 1.2 h, the frequency was 800 Hz, the duty cycle was 70%, and the electrolysis temperature was 60 °C. The electrolyte was stirred in the forward direction at a speed of 800 rpm. The vanadium precipitation on the positive electrode was filtered and thoroughly washed, then redissolved with a hydroxyethyl ethylenediamine triacetic acid solution, and secondary constant-current electrolysis was carried out in a two-chamber electrolytic cell with a current density of 400 mA / cm 2 , the area ratio of the positive and negative electrodes was 5:3, the distance between the positive and negative electrodes was 40 mm, the electrolysis time was 5 h, the electrolysis temperature was 60 °C. The secondary vanadium deposit on the positive electrode was filtered and thoroughly washed, and then sintered at 920 °C for 0.8 h to obtain 5.4 g of vanadium pentoxide with a recovery rate of 90%, and its purity was measured to be greater than 99.5 wt%.

[0039] Example 7

[0040] Take 500 ml of the leaching solution for vanadium extraction from waste catalysts, and measure its vanadium content to be 22 g / L (calculated as V2O5). Carry out constant-current pulse electrolysis in a two-chamber electrolytic cell. The positive electrode is a titanium-based ruthenium-iridium electrode, the negative electrode is graphite, and the polyimide resin membrane is used as the diaphragm. The area ratio of the positive and negative electrodes is 3:5, the distance between the positive and negative electrodes is 20 mm, and the current density is 800 mA / cm 2, the electrolysis time was 2.2 h, the frequency was 1200 Hz, the duty cycle was 60%, and the electrolysis temperature was 50 °C. The electrolyte was stirred forward at a speed of 900 rpm. The vanadium deposition on the positive electrode was filtered and washed thoroughly, redissolved with ethylenediamine solution, and subjected to secondary constant voltage electrolysis in a two-compartment electrolytic cell. The voltage was 20 V, the area ratio of the positive and negative electrodes was 3:5, the distance between the positive and negative electrodes was 40 mm, the electrolysis time was 1.8 h, the electrolysis temperature was 50 °C. The secondary vanadium deposit on the positive electrode was filtered and washed thoroughly, sintered at 980 °C for 0.9 h, and 10.6 g of vanadium pentoxide was obtained with a recovery rate of 96.4%. Its purity was measured to be greater than 99.5 wt%.

[0041] Example 8

[0042] Take 500 ml of the leaching solution for vanadium extraction from stone coal, and measure its vanadium content to be 18 g / L (calculated as V2O5). Constant current pulse electrolysis was carried out in a two-compartment electrolytic cell. The positive electrode was a boron-doped diamond thin film electrode, the negative electrode was sponge carbon, and the sulfonated polyethylene resin membrane was used as the diaphragm. The area ratio of the positive and negative electrodes was 3:1, the distance between the positive and negative electrodes was 10 mm, and the current density was 700 mA / cm 2 , the electrolysis time was 1.8 h, the frequency was 1100 Hz, the duty cycle was 50%, and the electrolysis temperature was 50 °C. The electrolyte was stirred forward at a speed of 700 rpm. The vanadium deposition on the positive electrode was filtered and washed thoroughly, redissolved with nitrilotriacetic acid solution, and subjected to secondary constant voltage electrolysis in a two-compartment electrolytic cell. The voltage was 30 V, the area ratio of the positive and negative electrodes was 3:1, the distance between the positive and negative electrodes was 30 mm, the electrolysis time was 2.8 h, the electrolysis temperature was 50 °C. The secondary vanadium deposit on the positive electrode was filtered and washed thoroughly, sintered at 930 °C for 0.9 h, and 8.5 g of vanadium pentoxide was obtained with a recovery rate of 94.4%. Its purity was measured to be greater than 99.5 wt%.

[0043] Example 9

[0044] Take 500 ml of the leaching solution for vanadium extraction from low-vanadium steel slag, and measure its vanadium content to be 42 g / L (calculated as V2O5). Constant current electrolysis was carried out in a single-compartment electrolytic cell. The positive electrode was a boron-doped diamond (BDD) thin film electrode, the negative electrode was a stainless steel plate, and the current density was 600 mA / cm 2 , the area ratio of the positive and negative electrodes was 4:1, the distance between the positive and negative electrodes was 8 mm, the electrolysis time was 3 h, the constant temperature of the electrolyte was 50 °C, and the electrolyte was stirred forward at a speed of 800 rpm. The vanadium deposition on the positive electrode was filtered and washed thoroughly, redissolved with saturated urea solution, and subjected to secondary constant voltage electrolysis in a single-compartment electrolytic cell. The electrolysis voltage was 20 V, the area ratio of the positive and negative electrodes was 4:1, the distance between the positive and negative electrodes was 8 mm, the electrolysis time was 1 h, the constant temperature of the electrolyte was 25 °C. The secondary vanadium deposit on the positive electrode was filtered and washed thoroughly, and acid dissolution was carried out with sulfuric acid (concentration 4 mol / L) to prepare vanadium battery electrolyte, and the concentration of the vanadium battery electrolyte was 1.8 mol / L.

[0045] Example 10

[0046] 500 ml of the leaching solution for extracting vanadium from stone coal was taken, and its vanadium content was determined to be 25 g / L (calculated as V2O5). Constant-current electrolysis was carried out in a single-chamber electrolytic cell. The positive electrode was a titanium-based ruthenium-iridium electrode, and the negative electrode was a graphite felt. The current density was 350 mA / cm 2 , the area ratio of the positive and negative electrodes was 5:1, the distance between the positive and negative electrodes was 15 mm, the electrolysis time was 2.0 h, the constant temperature of the electrolyte was 40 °C, and the electrolyte was stirred forward at a speed of 600 rpm. The vanadium deposited on the positive electrode was fully washed after filtration and then redissolved with a solution of triethylenetetramine hexamethylenephosphonic acid. Secondary constant-voltage electrolysis was carried out in a single-chamber electrolytic cell. The electrolysis voltage was 12 V, the area ratio of the positive and negative electrodes was 5:1, the distance between the positive and negative electrodes was 15 mm, the electrolysis time was 2.0 h, the constant temperature of the electrolyte was 40 °C. The vanadium deposit on the positive electrode after the second electrolysis was fully washed after filtration, and acid dissolution was carried out with hydrochloric acid (concentration: 5 mol / L) to prepare the vanadium battery electrolyte, and the concentration of the vanadium battery electrolyte was 1.7 mol / L.

[0047] The results of the examples show that the present invention is based on the application background of high-purity vanadium products, aiming to reduce the cost of vanadium extraction, improve the product purity, and reduce wastewater discharge. Using the vanadium-containing leaching solution as the raw material, an electrochemical method is proposed to regulate the instantaneous pH value on the electrode surface, so that pentavalent vanadium compounds can deposit vanadium at a controllable speed on the electrode surface, avoiding the co-deposition of impurity ions, directly simplifying the process steps for purifying high-purity vanadium, and thus reducing the process cost.

Claims

1. A method for preparing high-purity vanadium products based on electrochemical vanadium precipitation, characterized in that, Using the vanadium-containing leaching solution as raw material, vanadium is precipitated through electrochemical electrolysis, then the vanadium deposit is filtered, thoroughly washed and then redissolved, and secondary electrochemical electrolysis is carried out for vanadium precipitation; the secondary vanadium deposit is acid-dissolved to directly prepare the vanadium battery electrolyte, or directly sintered to produce high-purity vanadium pentoxide; The vanadium-containing leaching solution is the leaching solution generated by traditional vanadium extraction processes, including the vanadium-containing leaching solution generated by extracting vanadium from low-vanadium steel slag, extracting vanadium from stone coal, extracting vanadium from waste catalysts, extracting vanadium from petroleum coke or extracting vanadium from petroleum ash, and the vanadium content of the vanadium-containing leaching solution is 1 g / L to 200 g / L; The electrochemical electrolysis methods adopted include constant current electrolysis, constant voltage electrolysis or constant current pulse electrolysis, and the electrolysis device adopts a single-chamber electrolytic cell or a two-chamber electrolytic cell; When using a single-chamber electrolytic cell for electrolysis, the area ratio of the positive and negative electrodes is 1:10 to 10:1, and the distance between the positive and negative electrodes is 1 mm to 100 mm; when using a two-chamber electrolytic cell for electrolysis, the area ratio of the positive and negative electrodes is 1:5 to 5:1, the distance between the positive and negative electrodes is 5 mm to 50 mm, and a diaphragm is installed between the positive and negative electrodes; When constant current electrolysis is adopted, the current density range is 10 mA / cm 2 ~1000 mA / cm 2 , the electrolysis time is 0.5 - 10 h, and the electrolysis temperature is 25°C - 70°C; when constant voltage electrolysis is adopted, the voltage range is 1 V - 50 V, the electrolysis time is 0.5 - 10 h, and the electrolysis temperature is 25°C - 70°C; when constant current pulse electrolysis is adopted, the current density range is 10 mA / cm 2 ~1000 mA / cm 2 , the electrolysis time is 0.5 - 10 h, the frequency is 200 - 2000 Hz, the duty cycle is 20% - 80%, and the electrolysis temperature is 25°C - 70°C.

2. The method for preparing high-purity vanadium products based on electrochemically depositing vanadium as claimed in claim 1, characterized in that, The positive electrode is a dimensionally stable electrode, specifically one of a boron-doped diamond thin film electrode, a titanium-based ruthenium-iridium electrode, a titanium-based iridium-tantalum electrode, a titanium-based ruthenium-indium-tin electrode, a titanium-based tin-antimony oxide electrode, a titanium-based sub-titanium oxide electrode, and a titanium-based lead dioxide electrode; The negative electrode material includes at least one of a metal material and a carbon material, where: the metal material includes at least one of stainless steel, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, niobium, tantalum, zirconium, tungsten, cerium, aluminum, bismuth, rhenium, barium, osmium, tin, lead, gold, silver, platinum, palladium, iridium, rhodium, molybdenum, ruthenium; the carbon material includes any one of graphite felt, carbon felt, graphite, glassy carbon, boron-doped diamond, activated carbon, graphene, carbon fiber, carbon nanotube, carbon sponge; The electrode shape includes any one of sheet shape, rod shape, filament shape, granular shape and porous structure.

3. The method for preparing high-purity vanadium products based on electrochemically precipitating vanadium according to claim 1, characterized in that, When using a two-chamber electrolytic cell for electrolysis, the diaphragm is one of the diaphragms made of polybenzothiazole, polybenzimidazole, sulfonated sulfonated polyethylene, polyethersulfone, sulfonated polypropylene, polyimide, polysulfone, perfluorosulfonic acid resin, polyetheretherketone, perfluorocarboxylic acid resin, polyvinylidene fluoride resin, and the perfluorosulfonic acid resin adopts the Nafion series perfluorosulfonic acid membranes of DuPont Company, including Nafion212, Nafion115, Nafion211 or Nafion117.

4. The method for preparing high-purity vanadium products based on electrochemical vanadium precipitation according to claim 1, wherein The substances for washing the vanadium deposit include one or more of the following: water, ethanol, methanol, acetone, ethyl acetate, toluene, glycerol, white oil.

5. The method for preparing high-purity vanadium products based on electrochemical vanadium precipitation according to claim 1, wherein, The substances for redissolving the vanadium deposit after cleaning include one or more of the following: ethylenediamine, ammonia water, hydrogen peroxide, sodium hypochlorite, triethanolamine, urea, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, hydroxyethylethylenediaminetriacetic acid, aminotriacetic acid, hydroxyethylidene diphosphonic acid, aminotrimethylenephosphonic acid, ethylenediaminetetramethylenephosphonic acid, diethylenetriaminepentamethylenephosphonic acid, triethylenetetraminehexamethylenephosphonic acid, polyaminopolyetherylenetetramethylenephosphonic acid; 6. The method for preparing high-purity vanadium products based on electrochemical vanadium precipitation according to claim 1, characterized in that, The sediment obtained by the secondary electrochemical electrolysis method for vanadium precipitation is used to prepare the vanadium battery electrolyte by acid dissolution. The acids used include one or more of the following: hydrochloric acid, sulfuric acid, nitric acid, sulfamic acid, formic acid, acetic acid. The sediment obtained by the secondary electrochemical electrolysis method for vanadium precipitation is used to prepare vanadium pentoxide by sintering. The sintering temperature is 450°C to 1200°C, and the time is 0.5 h to 10 h.