Vanadium oxysulfate electrolyte based on shale vanadium-rich liquid and preparation method thereof

Abstract

The invention relates to a vanadyl sulfate electrolyte based on shale vanadium-rich liquid and a preparation method of the vanadyl sulfate electrolyte. According to the technical scheme, the shale vanadium-rich liquid is subjected to reduced pressure evaporation, and high-concentration vanadium-rich liquid is obtained; standing the high-concentration vanadium-rich liquid in a low-temperature environment for cooling crystallization, and carrying out solid-liquid separation for the first time to obtain a high-purity vanadium-rich liquid; according to the solid-to-liquid ratio of 1-15 Kg / t, seed crystals and the high-purity vanadium-rich liquid are mixed and stirred, and turbid liquid is obtained; crystallizing the turbid liquid in a constant-temperature environment; carrying out secondary solid-liquid separation to obtain vanadyl sulfate crystals; and dissolving the vanadyl sulfate crystal in a dilute sulfuric acid solution according to a solid-to-liquid ratio of 400-575 Kg / t to prepare the vanadyl sulfate electrolyte based on the shale vanadium-rich liquid. The method has the characteristics of being simple in process, low in medicament consumption, environment-friendly, high in safety and convenient to adjust the vanadium concentration of the electrolyte, the prepared vanadyl sulfate electrolyte based on the shale vanadium-rich liquid is high in purity, and separation of vanadium and impurities in the shale vanadium-rich liquid is effectively achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of vanadyl sulfate electrolytes. Specifically, it relates to a vanadyl sulfate electrolyte based on shale rich in vanadium and a preparation method thereof. Background Art

[0002] All-vanadium redox flow batteries have become a large-scale energy storage technology with a fast development process due to advantages such as large storage capacity, long service life, high charge and discharge efficiency, and fast response speed. The electrolyte of the vanadium battery stores the active substances of the battery and is the core of battery energy storage and conversion. As a basic electrolyte, vanadyl sulfate has a direct impact on the performance and service life of the battery. Currently, the mainstream preparation process of vanadyl sulfate is to dissolve high-purity vanadium pentoxide in sulfuric acid aqueous solution by heating activation, and then add a reducing agent to reduce pentavalent vanadium to tetravalent vanadium to obtain vanadyl sulfate. However, using high-purity vanadium pentoxide as a raw material results in high production costs. The valence of vanadium in the acidic vanadium-rich solution obtained by the mainstream vanadium extraction process from vanadium shale is +4, and the solution has the characteristics of high acidity and many impurities. It needs to go through processes such as pH adjustment, oxidation, vanadium precipitation, alkali dissolution, re-vanadium precipitation, and calcination to obtain high-purity vanadium pentoxide. This process flow is long, the consumption of reagents is large, and waste water and waste gas are generated during the production process, polluting the environment.

[0003] The patented technology of "A Method for Producing Vanadyl Sulfate Battery Electrolyte Using Vanadium-Containing Acid Leaching Solution" (CN113998735A) uses stone coal vanadium ore acid leaching solution or vanadium-containing acidic waste liquid as raw materials, and realizes the separation of vanadium and impurity ions through reduction - pH adjustment and two-stage multi-stage countercurrent extraction - multi-stage countercurrent stripping, and then removes oil to obtain high-purity vanadyl sulfate electrolyte. Although this process avoids the intermediate process of vanadium precipitation, it still has the problems of complex process flow and large consumption of reagents.

[0004] The patented technology of "A Method for Preparing 3.5-Valence Vanadyl Sulfate Electrolyte by Gas-Based Reduction of Ammonium Polyvanadate" (CN117832565A) uses ammonium polyvanadate as a raw material, passes a reducing mixed gas, and sets the temperature at 480 °C for reduction calcination. The obtained vanadium oxide is dissolved in sulfuric acid aqueous solution, and after vanadium adjustment, vanadyl sulfate electrolyte is obtained. This process flow is short, but it involves the use of mixed gas, is not easy to operate, has potential safety hazards, and waste gas is generated during the calcination process, which is not beneficial to the environment.

[0005] The patented technology of "A Method for Preparing High-Purity Vanadyl Sulfate Solution" (CN114772642A) mixes vanadium pentoxide, oxalic acid, dilute sulfuric acid, and a purification agent for heating reaction to obtain high-purity vanadyl sulfate solution. To ensure the complete conversion of pentavalent vanadium to tetravalent vanadium in this process, a large amount of oxalic acid is added as a reducing agent, which will remain in the solution and reduce the product purity, and further treatment is required.

[0006] In summary, the existing methods for preparing vanadyl sulfate electrolyte have disadvantages such as complex processes, high consumption of chemicals, low safety, and environmental pollution. The purity of the prepared vanadium electrolyte is not high. Summary of the Invention

[0007] The present invention aims to overcome the defects of the prior art and provides a method for preparing vanadyl sulfate electrolyte based on shale vanadium-rich liquid with simple process, low chemical consumption, environmental friendliness, and high safety. The vanadyl sulfate electrolyte prepared by this method has high purity and can realize the immediate preparation and use of the vanadyl sulfate electrolyte based on shale vanadium-rich liquid and the free regulation of vanadium concentration.

[0008] To achieve the above object, the specific steps of the technical solution adopted by the present invention are as follows:

[0009] Step 1: Subject the shale vanadium-rich liquid to vacuum evaporation to obtain a high-concentration vanadium-rich liquid.

[0010] In the shale vanadium-rich liquid: the pH is -0.6 to -0.1, and the valence state of V is +4; the chemical composition of the shale vanadium-rich liquid is: V is 15 to 45 g / L, Al is 3 to 8 g / L, Zn ≤ 2 g / L, Fe ≤ 1 g / L, K ≤ 2 g / L, Na ≤ 2 g / L, Ca ≤ 1 g / L, Mg ≤ 1 g / L.

[0011] Step 2: Let the high-concentration vanadium-rich liquid stand in a low-temperature environment for cooling crystallization, and perform the first solid-liquid separation to obtain a high-purity vanadium-rich liquid.

[0012] Step 3: According to a solid-liquid ratio of 1 to 15 Kg / t, mix the seed crystal with the high-purity vanadium-rich liquid, stir to obtain a suspension; place the suspension in a constant-temperature environment for crystallization; perform the second solid-liquid separation to obtain vanadyl sulfate crystals.

[0013] Step 4: According to a solid-liquid ratio of 400 to 575 Kg / t, dissolve the vanadyl sulfate crystals in a dilute sulfuric acid solution to prepare a vanadyl sulfate electrolyte based on shale vanadium-rich liquid.

[0014] The chemical composition of the vanadyl sulfate electrolyte based on shale vanadium-rich liquid is: V is 85 to 115 g / L, Al ≤ 41 mg / L, Zn ≤ 46 mg / L, Fe ≤ 34 mg / L, K ≤ 86 mg / L, Na ≤ 67 mg / L, Ca ≤ 24 mg / L, Mg ≤ 21 mg / L.

[0015] The pressure of the vacuum evaporation is -0.08 to -0.1 MPa, and the temperature of the vacuum evaporation is 90 to 120 °C.

[0016] In the high-concentration vanadium-rich liquid: the concentration of V is 75 to 90 g / L, and the concentration of Al is 10 to 20 g / L.

[0017] The temperature for cooling crystallization in the low-temperature environment is 4 to 15 °C, and the time for cooling crystallization in the low-temperature environment is 2 to 12 h.

[0018] In the high-purity vanadium-rich solution: the concentration of vanadium is 85 to 100 g / L, and the concentration of Al is 0.5 to 2 g / L.

[0019] The seed crystal is VOSO 4 ·5H 2 O, and the purity of the seed crystal is ≥99.9%.

[0020] The stirring time is 0.5 to 2 h.

[0021] The temperature for crystallization in the constant-temperature environment is 10 to 40 °C, and the time for crystallization in the constant-temperature environment is 6 to 30 h.

[0022] The concentration of the dilute sulfuric acid solution is 2 to 4 mol / L.

[0023] Due to the adoption of the above technical solution, the present invention has the following positive effects compared with the prior art:

[0024] 1. The present invention uses shale vanadium-rich solution as the raw material and adopts a process for preparing vanadyl sulfate by vacuum evaporation - two-stage crystallization. Compared with the traditional process of "pH adjustment - oxidation - vanadium precipitation - alkali dissolution - re-vanadium precipitation - calcination - reduction", the present invention does not require processes such as adjusting the solution pH, changing the valence state of vanadium, vanadium precipitation, and calcination. It not only shortens the process flow but also avoids the corresponding reagent consumption and high-temperature calcination reaction. Therefore, the present invention has the characteristics of simple process, low reagent consumption, and clean and efficient.

[0025] 2. The raw material of the present invention is a high-acid and high-salt solution. There are differences in the solubility and crystallization properties between the impurity sulfate and vanadyl sulfate in the high-acid and high-salt solution. Through vacuum evaporation, the first-stage crystallization removes the main impurity element aluminum, and the second-stage crystallization is vanadyl sulfate, effectively realizing the deep separation of vanadium and impurities. The vacuum evaporation adopted by the present invention can reduce the evaporation temperature, accelerate the evaporation rate, and reduce energy consumption compared with the existing atmospheric evaporation; the process adopted by the present invention does not produce wastewater, does not use gas, and does not generate gas. Therefore, the present invention not only has good vanadium and impurity separation effect, high purity of the vanadyl sulfate electrolyte prepared based on shale vanadium-rich solution, but also has the characteristics of environmental friendliness and high safety.

[0026] 3. The process for preparing vanadyl sulfate by vacuum evaporation - two-stage crystallization adopted by the present invention has good vanadium and impurity separation effect, low content of impurity ions in the prepared vanadyl sulfate, and the composition of the prepared vanadium electrolyte meets the requirements of the first-class product of the national standard (GB / T - 37204 - 2018); the vanadyl sulfate crystal prepared by the present invention is convenient for storage and transportation. According to needs, the vanadyl sulfate crystal is dissolved in the dilute sulfuric acid solution, and it can realize the immediate preparation and use of the vanadyl sulfate electrolyte based on shale vanadium-rich solution and the free regulation of vanadium concentration.

[0027] Therefore, the present invention has the characteristics of simple process, less reagent consumption, environmental friendliness, high safety, and convenient adjustment of the vanadium concentration in the electrolyte. The prepared vanadyl sulfate electrolyte based on shale vanadium-rich liquid has high purity, effectively realizing the separation of vanadium and impurities in the shale vanadium-rich liquid. Specific Embodiments

[0028] The following specific embodiments further describe the present invention, and do not limit its protection scope.

[0029] A vanadyl sulfate electrolyte based on shale vanadium-rich liquid and a preparation method thereof. The steps of the preparation method described in this specific embodiment are as follows:

[0030] Step 1: Subject the shale vanadium-rich liquid to vacuum evaporation to obtain a high-concentration vanadium-rich liquid.

[0031] In the shale vanadium-rich liquid: the pH is -0.6 to -0.1; the chemical composition of the shale vanadium-rich liquid is: V is 15 to 45 g / L, Al is 3 to 8 g / L, Zn ≤ 2 g / L, Fe ≤ 1 g / L, K ≤ 2 g / L, Na ≤ 2 g / L, Ca ≤ 1 g / L, Mg ≤ 1 g / L.

[0032] Step 2: Let the high-concentration vanadium-rich liquid stand in a low-temperature environment for cooling crystallization, and perform the first solid-liquid separation to obtain a high-purity vanadium-rich liquid.

[0033] Step 3: According to a solid-liquid ratio of 1 to 15 Kg / t, mix the seed crystals with the high-purity vanadium-rich liquid, stir to obtain a suspension; place the suspension in a constant-temperature environment for crystallization; perform the second solid-liquid separation to obtain vanadyl sulfate crystals.

[0034] Step 4: According to a solid-liquid ratio of 400 to 575 Kg / t, dissolve the vanadyl sulfate crystals in a dilute sulfuric acid solution to prepare a vanadyl sulfate electrolyte based on shale vanadium-rich liquid.

[0035] The chemical composition of the vanadyl sulfate electrolyte based on shale vanadium-rich liquid is: V is 85 to 115 g / L, Al ≤ 41 mg / L, Zn ≤ 46 mg / L, Fe ≤ 34 mg / L, K ≤ 86 mg / L, Na ≤ 67 mg / L, Ca ≤ 24 mg / L, Mg ≤ 21 mg / L.

[0036] The pressure of the vacuum evaporation is -0.08 to -0.1 MPa, and the temperature of the vacuum evaporation is 90 to 120 °C.

[0037] In the high-concentration vanadium-rich liquid: the concentration of V is 75 to 90 g / L, and the concentration of Al is 10 to 20 g / L.

[0038] The temperature of cooling crystallization in the low-temperature environment is 4-15 °C, and the time of cooling crystallization in the low-temperature environment is 2-12 h.

[0039] In the high-purity vanadium-rich solution: the concentration of vanadium is 85-100 g / L, and the concentration of Al is 0.5-2 g / L.

[0040] The time of stirring is 0.5-2 h.

[0041] The temperature of crystallization in the constant-temperature environment is 10-40 °C, and the time of crystallization in the constant-temperature environment is 6-30 h.

[0042] The concentration of the dilute sulfuric acid solution is 2-4 mol / L.

[0043] In this specific embodiment:

[0044] In the shale vanadium-rich solution: the valence state of V is +4;

[0045] The seed crystal is VOSO 4 ·5H 2 O, and the purity of the seed crystal is ≥99.9%.

[0046] Details are not described again in the examples.

[0047] Example 1

[0048] A vanadyl sulfate electrolyte based on shale vanadium-rich solution and its preparation method. The steps of the preparation method described in this example are as follows:

[0049] Step 1: Subject the shale vanadium-rich solution to vacuum evaporation to obtain a high-concentration vanadium-rich solution.

[0050] In the shale vanadium-rich solution: the pH is -0.6; the chemical composition of the shale vanadium-rich solution is: V is 45 g / L, Al is 5 g / L, Zn is 2 g / L, Fe is 1 g / L, K is 2 g / L, Na is 2 g / L, Ca is 1 g / L, and Mg is 1 g / L.

[0051] Step 2: Let the high-concentration vanadium-rich solution stand in a low-temperature environment for cooling crystallization, and perform the first solid-liquid separation to obtain a high-purity vanadium-rich solution.

[0052] Step 3: Mix the seed crystal with the high-purity vanadium-rich solution according to a solid-liquid ratio of 15 Kg / t, stir to obtain a suspension; place the suspension in a constant-temperature environment for crystallization; perform the second solid-liquid separation to obtain vanadyl sulfate crystals.

[0053] Step 4: Dissolve the vanadyl sulfate crystals in a dilute sulfuric acid solution according to a solid-liquid ratio of 575 Kg / t to prepare a vanadyl sulfate electrolyte based on shale vanadium-rich solution.

[0054] The chemical composition of the vanadyl sulfate electrolyte based on shale vanadium-rich solution is as follows: V is 115 g / L, Al is 41 mg / L, Zn is 46 mg / L, Fe is 34 mg / L, K is 86 mg / L, Na is 67 mg / L, Ca is 24 mg / L, and Mg is 21 mg / L.

[0055] The pressure of the vacuum evaporation is -0.1 MPa, and the temperature of the vacuum evaporation is 90 °C.

[0056] In the high-concentration vanadium-rich solution: the concentration of V is 90 g / L, and the concentration of Al is 10 g / L.

[0057] The temperature of cooling crystallization in the low-temperature environment is 4 °C, and the time of cooling crystallization in the low-temperature environment is 2 h.

[0058] In the high-purity vanadium-rich solution: the concentration of vanadium is 100 g / L, and the concentration of Al is 1.1 g / L.

[0059] The time of stirring is 0.5 h.

[0060] The temperature of crystallization in the constant-temperature environment is 10 °C, and the time of crystallization in the constant-temperature environment is 6 h.

[0061] The concentration of the dilute sulfuric acid solution is 2 mol / L.

[0062] Example 2

[0063] A vanadyl sulfate electrolyte based on shale vanadium-rich solution and its preparation method. The steps of the preparation method described in this example are as follows:

[0064] Step 1: Perform vacuum evaporation on the shale vanadium-rich solution to obtain a high-concentration vanadium-rich solution.

[0065] In the shale vanadium-rich solution: the pH is -0.1; the chemical composition of the shale vanadium-rich solution is as follows: V is 15 g / L, Al is 3 g / L, Zn is 0.5 g / L, Fe is 0.2 g / L, K is 0.6 g / L, Na is 0.5 g / L, Ca is 0.2 g / L, and Mg is 0.3 g / L.

[0066] Step 2: Let the high-concentration vanadium-rich solution stand in a low-temperature environment for cooling crystallization, and perform the first solid-liquid separation to obtain a high-purity vanadium-rich solution.

[0067] Step 3: Mix the seed crystal with the high-purity vanadium-rich solution according to a solid-liquid ratio of 1 Kg / t, stir to obtain a suspension; place the suspension in a constant-temperature environment for crystallization; perform the second solid-liquid separation to obtain vanadyl sulfate crystals.

[0068] Step 4: Dissolve the vanadyl sulfate crystals in a dilute sulfuric acid solution according to a solid-liquid ratio of 400 Kg / t to prepare a vanadyl sulfate electrolyte based on shale vanadium-rich solution.

[0069] The chemical composition of the vanadyl sulfate electrolyte based on shale vanadium-rich liquid is as follows: V is 85 g / L, Al is 28 mg / L, Zn is 31 mg / L, Fe is 20 mg / L, K is 56 mg / L, Na is 46 mg / L, Ca is 15 mg / L, and Mg is 14 mg / L.

[0070] The pressure of the vacuum evaporation is -0.08 MPa, and the temperature of the vacuum evaporation is 120 °C.

[0071] In the high-concentration vanadium-rich liquid: the concentration of V is 75 g / L, and the concentration of Al is 15 g / L.

[0072] The temperature of cooling crystallization in the low-temperature environment is 6 °C, and the time of cooling crystallization in the low-temperature environment is 6 h.

[0073] In the high-purity vanadium-rich liquid: the concentration of vanadium is 85 g / L, and the concentration of Al is 0.5 g / L.

[0074] The time of stirring is 2 h.

[0075] The temperature of crystallization in the constant-temperature environment is 20 °C, and the time of crystallization in the constant-temperature environment is 12 h.

[0076] The concentration of the dilute sulfuric acid solution is 4 mol / L.

[0077] Example 3

[0078] A vanadyl sulfate electrolyte based on shale vanadium-rich liquid and a preparation method thereof. The steps of the preparation method described in this example are as follows:

[0079] Step 1: Vacuum evaporate the shale vanadium-rich liquid to obtain a high-concentration vanadium-rich liquid.

[0080] In the shale vanadium-rich liquid: the pH is -0.3; the chemical composition of the shale vanadium-rich liquid is as follows: V is 25 g / L, Al is 4 g / L, Zn is 1.2 g / L, Fe is 0.6 g / L, K is 1.3 g / L, Na is 1.3 g / L, Ca is 0.5 g / L, and Mg is 0.5 g / L.

[0081] Step 2: Let the high-concentration vanadium-rich liquid stand in a low-temperature environment for cooling crystallization, and perform the first solid-liquid separation to obtain a high-purity vanadium-rich liquid.

[0082] Step 3: According to a solid-liquid ratio of 9 Kg / t, mix the seed crystal with the high-purity vanadium-rich liquid, stir to obtain a suspension; place the suspension in a constant-temperature environment for crystallization; perform the second solid-liquid separation to obtain vanadyl sulfate crystals.

[0083] Step 4: Dissolve the vanadyl sulfate crystals in a dilute sulfuric acid solution according to a solid-liquid ratio of 480 Kg / t to prepare a vanadyl sulfate electrolyte based on shale-rich vanadium solution.

[0084] The chemical composition of the vanadyl sulfate electrolyte based on shale-rich vanadium solution is: V is 96 g / L, Al is 32 mg / L, Zn is 36 mg / L, Fe is 27 mg / L, K is 67 mg / L, Na is 52 mg / L, Ca is 19 mg / L, and Mg is 17 mg / L.

[0085] The pressure of the vacuum evaporation is -0.09 MPa, and the temperature of the vacuum evaporation is 100 °C.

[0086] In the high-concentration vanadium-rich solution: the concentration of V is 79.2 g / L, and the concentration of Al is 12.8 g / L.

[0087] The temperature for cooling crystallization in the low-temperature environment is 15 °C, and the time for cooling crystallization in the low-temperature environment is 9 h.

[0088] In the high-purity vanadium-rich solution: the concentration of vanadium is 88.1 g / L, and the concentration of Al is 1.6 g / L.

[0089] The stirring time is 1.5 h.

[0090] The temperature for crystallization in the constant-temperature environment is 30 °C, and the time for crystallization in the constant-temperature environment is 25 h.

[0091] The concentration of the dilute sulfuric acid solution is 2.5 mol / L.

[0092] Example 4

[0093] A vanadyl sulfate electrolyte based on shale-rich vanadium solution and a preparation method thereof. The steps of the preparation method in this example are:

[0094] Step 1: Perform vacuum evaporation on the shale-rich vanadium solution to obtain a high-concentration vanadium-rich solution.

[0095] In the shale-rich vanadium solution: the pH is -0.5; the chemical composition of the shale-rich vanadium solution is: V is 35 g / L, Al is 8 g / L, Zn is 1.3 g / L, Fe is 0.8 g / L, K is 1.5 g / L, Na is 1.4 g / L, Ca is 0.7 g / L, and Mg is 0.6 g / L.

[0096] Step 2: Let the high-concentration vanadium-rich solution stand in a low-temperature environment for cooling crystallization, and perform the first solid-liquid separation to obtain a high-purity vanadium-rich solution.

[0097] Step 3: Mix the seed crystals with the high-purity vanadium-rich solution according to a solid-liquid ratio of 5 Kg / t, stir to obtain a suspension; place the suspension in a constant-temperature environment for crystallization; perform a second solid-liquid separation to obtain vanadyl sulfate crystals.

[0098] Step 4: Dissolve the vanadyl sulfate crystals in a dilute sulfuric acid solution according to a solid-liquid ratio of 540 Kg / t to prepare a vanadyl sulfate electrolyte based on shale vanadium-rich solution.

[0099] The chemical composition of the vanadyl sulfate electrolyte based on shale vanadium-rich solution is: V is 108 / L, Al is 37 mg / L, Zn is 42 mg / L, Fe is 31 mg / L, K is 77 mg / L, Na is 59 mg / L, Ca is 22 mg / L, and Mg is 19 mg / L.

[0100] The pressure of the vacuum evaporation is -0.084 MPa, and the temperature of the vacuum evaporation is 110 °C.

[0101] In the high-concentration vanadium-rich solution: the concentration of V is 85.7 g / L, and the concentration of Al is 20 g / L.

[0102] The temperature for cooling crystallization in the low-temperature environment is 9 °C, and the time for cooling crystallization in the low-temperature environment is 12 h.

[0103] In the high-purity vanadium-rich solution: the concentration of vanadium is 94.2 g / L, and the concentration of Al is 2 g / L.

[0104] The stirring time is 1 h.

[0105] The temperature for crystallization in the constant-temperature environment is 40 °C, and the time for crystallization in the constant-temperature environment is 30 h.

[0106] The concentration of the dilute sulfuric acid solution is 3 mol / L.

[0107] This specific embodiment has the following positive effects compared with the prior art:

[0108] 1. This specific embodiment uses shale vanadium-rich solution as the raw material and adopts a vanadyl sulfate preparation process of vacuum evaporation - two-stage crystallization. Compared with the traditional process flow of "pH adjustment - oxidation - vanadium precipitation - alkali dissolution - re-vanadium precipitation - calcination - reduction", this specific embodiment does not require processes such as adjusting the solution pH, changing the valence state of vanadium, vanadium precipitation, and calcination. It not only shortens the process flow but also avoids the corresponding reagent consumption and high-temperature calcination reaction. Therefore, this specific embodiment has the characteristics of simple process, less reagent consumption, and clean and efficient.

[0109] 2. The raw material of this specific embodiment is a high-acid and high-salt solution. There are differences in the solubility and crystallization properties of the impurity sulfate and vanadyl sulfate in the high-acid and high-salt solution. Through vacuum evaporation, the first-stage crystallization removes the main impurity element aluminum, and the second-stage crystallization of vanadyl sulfate effectively realizes the deep separation of vanadium and impurities. The vacuum evaporation adopted in this specific embodiment can reduce the evaporation temperature, accelerate the evaporation rate, and reduce energy consumption compared with the existing atmospheric evaporation; the process adopted in this specific embodiment does not produce wastewater, and does not use or generate gases. Therefore, this specific embodiment not only has good vanadium-impurity separation effect, but also the prepared vanadyl sulfate electrolyte based on shale-rich vanadium solution has high purity, and has the characteristics of environmental friendliness and high safety.

[0110] 3. The vanadium-impurity separation effect of the vanadyl sulfate preparation process with vacuum evaporation - two-stage crystallization adopted in this specific embodiment is good, the content of impurity ions in the prepared vanadyl sulfate is low, and the composition of the prepared vanadium electrolyte meets the requirements of the first-class product in the national standard (GB / T - 37204 - 2018); the vanadyl sulfate crystals prepared in this specific embodiment are convenient for storage and transportation. Then, according to needs, the vanadyl sulfate crystals are dissolved in dilute sulfuric acid solution, and the vanadyl sulfate electrolyte based on shale-rich vanadium solution can be prepared and used immediately, and the vanadium concentration can be freely adjusted.

[0111] Therefore, this specific embodiment has the characteristics of simple process, less reagent consumption, environmental friendliness, high safety, and convenient adjustment of the vanadium concentration in the electrolyte. The prepared vanadyl sulfate electrolyte based on shale-rich vanadium solution has high purity, and effectively realizes the separation of vanadium and impurities in the shale-rich vanadium solution.

Claims

1. A method for preparing a vanadyl sulfate electrolyte based on shale vanadium-rich liquid, characterized in that The specific steps of the preparation method are: Step 1, decompressing and evaporating the vanadium-rich liquid from shale to obtain a high-concentration vanadium-rich liquid; The shale vanadium-rich liquid has a pH of -0.6 to -0.1 and a valence of V of +4. The chemical composition of the shale vanadium-rich liquid is: V is 15 to 45 g / L, Al is 3 to 8 g / L, Zn≤2 g / L, Fe≤1 g / L, K≤2 g / L, Na≤2 g / L, Ca≤1 g / L, and Mg≤1 g / L. Step 2, placing the high-concentration vanadium-rich liquid in a low-temperature environment for cooling and crystallization, performing a first solid-liquid separation to obtain a high-purity vanadium-rich liquid; Step 3, according to a solid-liquid ratio of 1 to 15 kg / t, the seed crystals are mixed with the high-purity vanadium-rich liquid, and stirred to obtain a suspension; the suspension is placed in a constant temperature environment for crystallization; a second solid-liquid separation is performed to obtain vanadyl sulfate crystals; Step 4, dissolving the vanadyl sulfate crystals in a dilute sulfuric acid solution at a solid-liquid ratio of 400 to 575 kg / t to prepare a vanadyl sulfate electrolyte based on shale vanadium-rich liquid; The vanadyl sulfate electrolyte based on shale vanadium-rich liquid has: V of 85-115 g / L, Al≤41 mg / L, Zn≤46 mg / L, Fe≤34 mg / L, K≤86 mg / L, Na≤67 mg / L, Ca≤24 mg / L, and Mg≤21 mg / L.

2. The method for preparing vanadyl sulfate electrolyte based on shale vanadium-rich liquid according to claim 1, characterized in that: The pressure of the reduced pressure evaporation is -0.08 to -0.1 MPa, and the temperature of the reduced pressure evaporation is 90 to 120°C.

3. The method for preparing vanadyl sulfate electrolyte based on shale vanadium-rich liquid according to claim 1, characterized in that: In the high-concentration vanadium-rich solution, the concentration of V is 75-90 g / L, and the concentration of Al is 10-20 g / L.

4. The method for preparing vanadyl sulfate electrolyte based on shale vanadium-rich liquid according to claim 1, characterized in that: The temperature of the cooling crystallization in the low temperature environment is 4 to 15° C., and the time of the cooling crystallization in the low temperature environment is 2 to 12 hours.

5. The method for preparing vanadyl sulfate electrolyte based on shale vanadium-rich liquid according to claim 1, characterized in that: In the high-purity vanadium-rich solution, the concentration of vanadium is 85-100 g / L, and the concentration of Al is 0.5-2 g / L.

6. The method for preparing vanadyl sulfate electrolyte based on shale vanadium-rich liquid according to claim 1, characterized in that: The seed crystal is VOSO4·5H2O, and the purity of the seed crystal is ≥99.9%.

7. The method for preparing vanadyl sulfate electrolyte based on shale vanadium-rich liquid according to claim 1, characterized in that: The stirring time is 0.5 to 2 hours.

8. The method for preparing vanadyl sulfate electrolyte based on shale vanadium-rich liquid according to claim 1, characterized in that: The crystallization temperature in the constant temperature environment is 10-40° C., and the crystallization time in the constant temperature environment is 6-30 hours.

9. The method for preparing vanadyl sulfate electrolyte based on shale vanadium-rich liquid according to claim 1, characterized in that: The concentration of the dilute sulfuric acid solution is 2-4 mol / L.

10. A vanadyl sulfate electrolyte based on shale vanadium-rich liquid, characterized in that: The vanadyl sulfate electrolyte based on shale vanadium-rich liquid is a vanadyl sulfate electrolyte based on shale vanadium-rich liquid prepared by the method for preparing a vanadyl sulfate electrolyte based on shale vanadium-rich liquid according to any one of claims 1 to 9.