A kind of all-ionic liquid extraction system and the method for preparing vanadium electrolyte based on all-ionic liquid extraction system short process

Abstract

The application discloses a kind of whole ionic liquid extraction system and the method for preparing vanadium electrolyte based on whole ionic liquid extraction system short process, belongs to vanadium product preparation technical field.Specific scheme is as follows: (1) adding sulfuric acid and leaching aid to vanadium-containing material, after 4-12h reaction, filtering, obtain vanadium-containing mother liquor;(2) vanadium-containing mother liquor is added to whole ionic liquid extraction system, obtain vanadium extraction ionic liquid;(3) adding sulfuric acid to vanadium extraction ionic liquid for stripping, obtain vanadium-containing acid liquor;(4) vanadium-containing acid liquor is added with sulfuric acid again or directly evaporated and concentrated, obtain vanadium electrolyte.The method of the application overcomes the drawbacks that conventional extractant and solvent are volatile and pollute the environment, improves the recovery rate of vanadium, and the prepared vanadium electrolyte has low impurity content, which is a green and sustainable method.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vanadium product preparation, and particularly relates to a full ionic liquid extraction system and a method for preparing vanadium electrolyte based on the full ionic liquid extraction system. BACKGROUND

[0002] With the continuous development of industrial economy, renewable energy is becoming more and more important in modern society, and solar and wind power generation has been widely used. Due to the instability of the electric energy generated by solar and wind power generation, these electric energies cannot be directly integrated into the power grid. Redox flow batteries have the characteristics of energy storage and energy conversion and can be implemented at different locations, and are a promising energy storage system.

[0003] Vanadium battery is a kind of redox flow battery. Vanadium electrolyte is one of the key materials of vanadium battery, and the concentration and electrochemical activity of vanadium ions in vanadium electrolyte determine the energy density of vanadium battery, which plays a crucial role in the development of vanadium battery. The active substance in vanadium electrolyte is vanadyl ion, which is a key material in all-vanadium redox flow battery. High vanadyl ion concentration and purity in electrolyte are the material basis for high comprehensive electrical performance of vanadium battery. Generally, vanadium electrolyte is prepared by using ammonium metavanadate or ammonium polyvanadate as raw material, calcining to obtain high-purity vanadium pentoxide, and then preparing vanadyl sulfate electrolyte through chemical reduction-electrochemical reduction. There are many problems such as complex process, complicated process, high cost and so on.

[0004] Therefore, it is necessary to develop a new and more simplified short process vanadium electrolyte production process to reduce production cost while ensuring the purity of vanadyl sulfate product, and realize efficient and clean production of vanadium electrolyte. SUMMARY

[0005] In view of the deficiencies of the widely used vanadium electrolyte preparation method at present, the purpose of the present application is to provide a full ionic liquid extraction system and a method for preparing vanadium electrolyte based on the full ionic liquid extraction system. The method for preparing vanadium electrolyte provided by the present application has the advantages of green environmental protection, lower cost and higher efficiency compared with the traditional method, and has a good application prospect.

[0006] To achieve the above-mentioned purpose of the application, the technical scheme adopted by the present application is as follows: a full ionic liquid extraction system, comprising an extractant and a diluent; the extractant is one or a mixture of two in any proportion of [TOMA][EHEHP], [TOMA][DEHP], [P 4444 ][EHEHP] or [P 4444 ][DEHP]; the diluent is [C n mim][NTf2], [C n mim][PF6] or [C na mixture of one or both of the following in any ratio: [TOMA][SbF6] and [P44414][SbF6], wherein n = 2-8.

[0007] Further, the above-mentioned all-ionic liquid extraction system has a volume ratio of extractant:diluent = 1:3-5.

[0008] Further, the above-mentioned all-ionic liquid extraction system has a preparation method of the extractant comprising the following steps:

[0009] (1) dissolving sodium hydroxide and methyltrioctylammonium chloride or tetrabutylphosphonium bromide in isopropyl alcohol, stirring at 30-40°C for 24-26 h after uniform mixing, filtering to obtain [TOMA][OH] intermediate or [P44414][OH] intermediate; 4444 [OH] intermediate;

[0010] (2) dissolving 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester or di(2-ethylhexyl)phosphate in isopropyl alcohol, adding [TOMA][OH] intermediate or [P44414][OH] intermediate thereto, stirring at 30-40°C for 24-26 h, and removing isopropyl alcohol by rotary evaporation to obtain [TOMA][EHEHP], [TOMA][DEHP], [P44414][EHEHP] or [P44414][DEHP], respectively. 4444 [OH] intermediate; 4444 [OH] intermediate; 4444 [OH] intermediate;

[0011] A method for preparing vanadium electrolyte based on an all-ionic liquid extraction system short process, which uses the above-mentioned all-ionic liquid extraction system and comprises the following steps:

[0012] (1) adding sulfuric acid and leaching aid to vanadium-containing material, filtering after reacting for 4-12 h to obtain vanadium-containing mother liquor;

[0013] (2) adding the vanadium-containing mother liquor to the all-ionic liquid extraction system to obtain vanadium extraction ionic liquid;

[0014] (3) adding sulfuric acid to the vanadium extraction ionic liquid for stripping to obtain vanadium-containing acid liquor;

[0015] (4) adding sulfuric acid to the vanadium-containing acid liquor again or directly evaporating and concentrating to obtain vanadium electrolyte.

[0016] Further, the above-mentioned method has that in step (1), the leaching aid is a mixture of one or both of the following in any ratio: ammonium sulfate, calcium fluoride or sodium tripolyphosphate.

[0017] Further, the above-mentioned method has that in step (1), the amount of the leaching aid is 1-5% of the mass of the vanadium-containing material.

[0018] Further, in the above method, in step (1), the concentration of the sulfuric acid is 10-25% by mass percentage.

[0019] Further, in the above method, in step (2), the ratio of the vanadium-containing mother liquor to the ionic liquid extraction system is 1:0.2-2 by volume ratio.

[0020] Further, in the above method, in step (3), the ratio of the vanadium extraction ionic liquid to the sulfuric acid is 1-5:1 by volume ratio; the back extraction is carried out at 20-80°C for 10-60 min; and the concentration of the sulfuric acid is 5-25% by mass percentage.

[0021] Further, in the above method, in step (4), sulfuric acid is added again to adjust the vanadium concentration in the obtained vanadium electrolyte to 1.5-2.0 mol / L; and the concentration of the sulfuric acid is 5-25% by mass percentage.

[0022] The present application has the following beneficial effects:

[0023] 1. The method for preparing vanadium electrolyte based on a short process of a full ionic liquid extraction system provided by the present application adopts a full ionic liquid extraction system, thereby avoiding the long process of obtaining high-purity vanadium pentoxide by calcining ammonium metavanadate or ammonium polyvanadate, and then preparing vanadyl sulfate electrolyte through chemical reduction-electrochemical reduction.

[0024] 2. The method provided by the present application has simple preparation method, short process, low production cost, convenient recovery, recyclable use, small environmental pollution, and optimized vanadyl sulfate electrolyte production process, thereby achieving great economic and social benefits.

[0025] 3. The method provided by the present application overcomes the drawbacks of conventional extractants and solvents, such as easy volatilization and environmental pollution, improves the vanadium recovery rate, and prepares vanadium electrolyte with low impurity content, thereby being a green and sustainable method. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is the nuclear magnetic spectrum of [TOMA][EHEHP].

[0027] Figure 2 is the nuclear magnetic spectrum of [TOMA][DEHP].

[0028] Figure 3 is the nuclear magnetic spectrum of [P 4444 ][EHEHP].

[0029] Figure 4 is the nuclear magnetic spectrum of [P 4444 ][DEHP]. DETAILED DESCRIPTION

[0030] In order to better understand the above technical solutions, the technical solutions of the embodiments of the present application are described in detail below through the drawings and specific embodiments. It should be understood that the specific features in the embodiments of the present application and the specific features in the embodiments are detailed descriptions of the technical solutions of the embodiments of the present application, rather than limitations of the technical solutions of the present application. In the case of no conflict, the technical features in the embodiments of the present application and the embodiments can be combined with each other.

[0031] In a first aspect of the embodiments of the present application, a full ionic liquid extraction system is provided, comprising an extractant and a diluent; the extractant is one or a mixture of any proportion of two of [TOMA][EHEHP], [TOMA][DEHP], [P 4444 ][EHEHP] or [P 4444 ][DEHP]; the diluent is one or a mixture of any proportion of two of [C n mim][NTf2], [C n mim][PF6] or [C n mim][SbF6], wherein n=2-8.

[0032] The full ionic liquid extraction system provided by the present application can extract vanadium in a vanadium-containing mother liquor into an ionic liquid. Both the extractant and the diluent used in the full ionic liquid extraction system are ionic liquids, which are environmentally friendly compared to organic or inorganic solvents. Moreover, the full ionic liquid extraction system can be recovered by stripping, which is convenient and can be reused.

[0033] In some possible embodiments, further, in the full ionic liquid extraction system, the extractant:diluent=1:3-5 by volume ratio.

[0034] The concentration of the extractant has a significant impact on the extraction rate. When the extractant:diluent=1:4, the extraction rate is higher. Increasing the amount of the extractant does not significantly improve the extraction rate. Considering the economic cost, the present application is preferably extractant:diluent=1:4.

[0035] In some possible embodiments, further, the preparation method of the extractant in the full ionic liquid extraction system comprises the following steps:

[0036] (1) Dissolve 4 parts of sodium hydroxide and 30-40 parts of methyltrioctylammonium chloride or tetrabutylphosphonium bromide in 200 parts of isopropanol, mix uniformly, and stir at 30-40℃ for 24-26h, filter to obtain the [TOMA][OH] intermediate or the [P 4444 ][OH] intermediate;

[0037] (2) 30-40 parts of 2-ethylhexyl phosphonic acid mono 2-ethylhexyl ester or di(2-ethylhexyl)phosphonate is dissolved in 200 parts of isopropyl alcohol, and [TOMA][OH] intermediate or [P 4444 ][OH] intermediate is added thereto, stirred at 30-40°C for 24-26 h, and isopropyl alcohol is removed by rotary evaporation to obtain [TOMA][EHEHP], [TOMA][DEHP], [P 4444 ][EHEHP], or [P 4444 ][DEHP], respectively.

[0038] In a second aspect of the embodiment of the present application, a method for preparing vanadium electrolyte based on a short process of a full ionic liquid extraction system is provided, and the method comprises the following steps:

[0039] (1) Sulfuric acid and a leaching aid are added to vanadium-containing material, and after reaction for 4-12 h, filtration is performed to obtain a vanadium-containing mother liquor;

[0040] (2) The vanadium-containing mother liquor is added to the full ionic liquid extraction system to obtain a vanadium extraction ionic liquid;

[0041] (3) Sulfuric acid is added to the vanadium extraction ionic liquid for stripping to obtain a vanadium-containing acid liquor;

[0042] (4) Sulfuric acid is added to the vanadium-containing acid liquor or direct evaporation is performed to concentrate the vanadium-containing acid liquor to obtain a vanadium electrolyte.

[0043] The method for preparing vanadium electrolyte based on a short process of a full ionic liquid extraction system provided by the present application extracts vanadium from vanadium-containing material by using sulfuric acid and a leaching aid to obtain a vanadium-containing mother liquor, thereby avoiding the step of obtaining high-purity vanadium pentoxide by calcination, and the method is simple and energy-saving. The vanadium in the vanadium-containing mother liquor is extracted by using a full ionic liquid extraction system, and the vanadium is extracted into sulfuric acid by stripping with sulfuric acid to obtain a vanadium-containing acid liquor, so that the vanadium-containing acid liquor can be obtained only by a simple extraction step, and the method is simple, and the full ionic liquid extraction system can be recovered after stripping and reused, thereby greatly reducing the production cost and not polluting the environment.

[0044] In some possible embodiments, the vanadium-containing material can be commercially available ammonium metavanadate or ammonium polyvanadate crude product (with a purity of less than 80%), or any mineral containing vanadium elements. If any mineral containing vanadium elements is used, the material is first crushed into particles with a particle size of less than 2 mm.

[0045] In some possible embodiments, further, in the above method, in step (1), the leaching aid is one of ammonium sulfate, calcium fluoride or sodium tripolyphosphate, or a mixture of any two thereof in any ratio.

[0046] The application adopts the synergistic effect of ammonium sulfate, calcium fluoride or sodium tripolyphosphate and sulfuric acid, so that vanadium can be quickly leached out.

[0047] In some possible embodiments, further to the above method, in step (1), the amount of the leaching aid is 1-5% of the mass of the vanadium-containing material.

[0048] In some possible embodiments, further to the above method, in step (1), the concentration of the sulfuric acid is 10-25% by mass percentage.

[0049] When the concentration of the sulfuric acid is 10-25%, the leaching rate is relatively high, and the leaching rate does not increase significantly with the further increase of the concentration of the sulfuric acid; considering the economic cost and safety, the application preferably has the concentration of the sulfuric acid being 10-25%.

[0050] In some possible embodiments, further to the above method, in step (2), the vanadium-containing mother liquor: the all-ionic liquid extraction system = 1:0.2-2 by volume ratio.

[0051] In some possible embodiments, further to the above method, in step (3), the vanadium extraction ionic liquid: sulfuric acid = 1-5:1 by volume ratio; the back extraction is carried out at 20-80℃ for 10-60min; and the concentration of the sulfuric acid is 5-25% by mass percentage.

[0052] When the concentration of the sulfuric acid is 5-25%, the back extraction rate is relatively high, and the back extraction rate does not increase significantly with the further increase of the concentration of the sulfuric acid; considering the economic cost and safety, the application preferably has the concentration of the sulfuric acid being 5-25%.

[0053] In some possible embodiments, further to the above method, in step (4), the sulfuric acid is added again to adjust the vanadium concentration in the obtained vanadium electrolyte to be 1.5-3.0mol / L; and the concentration of the sulfuric acid is 5-25% by mass percentage.

[0054] Through the method of the application, the vanadium electrolyte with the vanadium concentration greater than 1.7mol / L can be obtained.

[0055] Example 1

[0056] (I) Preparation of ionic liquid [TOMA][EHEHP]

[0057] 20g of sodium hydroxide and 200g of methyltrioctylammonium chloride were dissolved in 1000g of isopropyl alcohol, uniformly mixed, stirred at 35℃ for 24h, and filtered to remove the generated NaCl by using a sand core filtering device to obtain the [TOMA][OH] intermediate.

[0058] The 150 g 2-ethylhexyl phosphonic acid mono 2-ethylhexyl ester is dissolved in 1000 g isopropyl alcohol, and [TOMA][OH] intermediate is added thereto, stirred at 35°C for 24 h, and isopropyl alcohol is removed by rotary evaporation to obtain a viscous ionic liquid [TOMA][EHEHP], and the nuclear magnetic spectrum is as follows: Figure 1 .

[0059] (II) Preparation of the whole ionic liquid extraction system

[0060] The [TOMA][EHEHP]:[C4mim][NTf2] is taken in a volume ratio of 2:8, mixed uniformly to obtain the whole ionic liquid extraction system ([TOMA][EHEHP]-[C4mim][NTf2]).

[0061] (III) Preparation of the vanadium electrolyte

[0062] (1) 100 g of ammonium metavanadate is taken, 200 mL of 15 wt% sulfuric acid and 2 g of leaching aid ammonium sulfate are added, and the mixture is reacted at room temperature for 6 h, and then filtered to obtain a vanadium-containing mother liquor;

[0063] (2) 180 mL of the vanadium-containing mother liquor is added to 100 mL of [TOMA][EHEHP]-[C4mim][NTf2], and the mixture is extracted at 25°C for 30 min to extract vanadium into the ionic liquid to obtain a vanadium extraction ionic liquid;

[0064] (3) The vanadium extraction ionic liquid is added to 15 wt% sulfuric acid in a volume ratio of 3:1, and the mixture is stripped at 30°C for 30 min to obtain a vanadium-containing acid solution;

[0065] (4) 190 mL of 15 wt% sulfuric acid is added to the vanadium-containing acid solution to obtain a vanadium electrolyte, and the vanadium concentration in the obtained vanadium electrolyte is 1.73 mol / L.

[0066] Example 2

[0067] (I) Preparation of the ionic liquid [TOMA][DEHP]

[0068] 20 g of sodium hydroxide and 200 g of methyltrioctylammonium chloride are dissolved in 1000 g of isopropyl alcohol, and the mixture is stirred at 35°C for 24 h, and then filtered using a sand core filter device to remove the generated NaCl to obtain the [TOMA][OH] intermediate.

[0069] 160 g of di(2-ethylhexyl)phosphate is dissolved in 1000 g of isopropyl alcohol, and the [TOMA][OH] intermediate is added thereto, and the mixture is stirred at 35°C for 24 h, and then isopropyl alcohol is removed by rotary evaporation to obtain a viscous ionic liquid [TOMA][DEHP], and the nuclear magnetic spectrum is as follows:Figure 2 .

[0070] (II) Preparation of the whole ionic liquid extraction system

[0071] Take [TOMA][DEHP] and [C4mim][NTf2] in a volume ratio of 2:8, mix well to obtain the whole ionic liquid extraction system ([TOMA][DEHP]-[C4mim][NTf2]).

[0072] (III) Preparation of the vanadium electrolyte

[0073] (1) Take 100 g of ammonium metavanadate, add 200 mL of 18 wt% concentrated sulfuric acid and 2 g of leaching aid ammonium sulfate, react at room temperature for 6 h, then filter to obtain a vanadium-containing mother liquor;

[0074] (2) Add 180 mL of the vanadium-containing mother liquor to 100 mL of [TOMA][DEHP]-[C4mim][NTf2], extract at 25°C for 30 min, extract the vanadium into the ionic liquid to obtain a vanadium extraction ionic liquid;

[0075] (3) Add 18 wt% concentrated sulfuric acid to the vanadium extraction ionic liquid in a volume ratio of vanadium extraction ionic liquid:sulfuric acid = 4:1, back-extract at 30°C for 20 min to obtain a vanadium-containing acid solution;

[0076] (4) Add 200 mL of 18 wt% concentrated sulfuric acid to the vanadium-containing acid solution to obtain a vanadium electrolyte, and the vanadium concentration in the obtained vanadium electrolyte is 1.72 mol / L.

[0077] Example 3

[0078] (I) Preparation of ionic liquid [P 4444 ][EHEHP]

[0079] Dissolve 20 g of sodium hydroxide and 180 g of tetrabutylphosphonium bromide in 1000 g of isopropyl alcohol, mix well, and stir at 35°C for 24 h. Filter to remove the generated NaBr using a sand core filter device to obtain the [P 4444 ][OH] intermediate.

[0080] Dissolve 150 g of 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester in 1000 g of isopropyl alcohol, add the [P 4444 ][OH] intermediate, stir at 35°C for 24 h, and remove the isopropyl alcohol by rotary evaporation to obtain the viscous ionic liquid [P 4444 ][EHEHP], and the nuclear magnetic resonance spectrum is as follows Figure 3 .

[0081] (II) Preparation of the whole ionic liquid extraction system

[0082] [P 4444 ][EHEHP]-[C4mim][NTf2] = 2:8, take [P 4444 ][EHEHP] and [C4mim][NTf2], mix well, get the whole ionic liquid extraction system ([P 4444 ][EHEHP]-[C4mim][NTf2]).

[0083] (Three) Preparation of vanadium electrolyte

[0084] (1) Take 100g ammonium metavanadate, add 200mL of 20wt% concentration sulfuric acid and 2g of leaching aid sodium tripolyphosphate, react at room temperature for 6h, then filter, get vanadium-containing mother liquor;

[0085] (2) Add 180mL of vanadium-containing mother liquor to 100mL of [P 4444 ][EHEHP]-[C4mim][NTf2], extract for 30min at 25℃, extract vanadium into ionic liquid, get vanadium extraction ionic liquid;

[0086] (3) According to the volume ratio, vanadium extraction ionic liquid: sulfuric acid = 3:1, add 20wt% concentration sulfuric acid to the vanadium extraction ionic liquid, back extraction for 25min at 30℃, get vanadium-containing acid liquor;

[0087] (4) Add 215mL of 20wt% concentration sulfuric acid to the vanadium-containing acid liquor, get vanadium electrolyte, the vanadium concentration in the obtained vanadium electrolyte is 1.71mol / L.

[0088] Example 4

[0089] (I) Preparation of ionic liquid [P 4444 ][DEHP]

[0090] Dissolve 20g of sodium hydroxide and 180g of tetrabutylphosphonium bromide in 1000g of isopropyl alcohol, mix well, then stir at 35℃ for 24h, filter out the generated NaBr using a sand core filter device, get [P 4444 ][OH] intermediate.

[0091] Dissolve 160g of di(2-ethylhexyl) phosphate in 1000g of isopropyl alcohol, add [P 4444 ][OH] intermediate to it, stir at 35℃ for 24h, remove isopropyl alcohol by rotary evaporation, get viscous ionic liquid [[P 4444 ][DEHP], the nuclear magnetic resonance spectrum is as follows Figure 4 .

[0092] (II) Preparation of whole ionic liquid extraction system

[0093] [DEHP] : [C4mim] [NTf2] = 2:8, taking [P 4444 ][DEHP]:[C4mim][NTf2] = 2:8, taking [P 4444 ][DEHP] and [C4mim][NTf2], mixed evenly, to get the whole ionic liquid extraction system ([P 4444 ][DEHP]-[C4mim][NTf2])

[0094] (Three) Preparation of vanadium electrolyte

[0095] (1) Take 100 g of ammonium metavanadate, add 200 mL of 20 wt% concentrated sulfuric acid and 2 mg of leaching aid calcium fluoride, react at room temperature for 6 h, then filter to obtain a vanadium-containing mother liquor;

[0096] (2) Add 180 mL of vanadium-containing mother liquor to 100 mL of [P 4444 ][DEHP]-[C4mim][NTf2], extract for 30 min at 25°C, extract vanadium into ionic liquid to obtain vanadium extraction ionic liquid;

[0097] (3) According to the volume ratio, vanadium extraction ionic liquid: sulfuric acid = 3:1, add 20 wt% concentrated sulfuric acid to the vanadium extraction ionic liquid, and extract at 30°C for 25 min to obtain a vanadium-containing acid solution;

[0098] (4) Add 220 mL of 20 wt% concentrated sulfuric acid to the vanadium-containing acid solution to obtain a vanadium electrolyte, and the vanadium concentration in the obtained vanadium electrolyte is 1.75 mol / L.

[0099] Example 5

[0100] (One) Preparation of vanadium electrolyte

[0101] (1) Take vanadium-containing material (vanadium concentration of 1 wt%), first crush the vanadium-containing material into particles with a particle size of less than 2 mm. Take 500 g of crushed vanadium-containing material, add 800 mL of 15 wt% concentrated sulfuric acid and 10 g of leaching aid ammonium sulfate, react at room temperature for 6 h, then filter to obtain a vanadium-containing mother liquor;

[0102] (2) Add 700 mL of vanadium-containing mother liquor to 500 mL of whole ionic liquid extraction system as shown in Table 1, extract at 25°C for 50 min, extract vanadium into ionic liquid to obtain vanadium extraction ionic liquid;

[0103] (3) According to the volume ratio, vanadium extraction ionic liquid: sulfuric acid = 3:1, add 15 wt% concentrated sulfuric acid to the vanadium extraction ionic liquid, respectively, and extract at 30°C for 30 min to obtain a vanadium-containing acid solution;

[0104] (4) The vanadium-containing solution is evaporated and concentrated to 25 mL to obtain a vanadium electrolyte, and the vanadium concentration in the obtained vanadium electrolyte is shown in Table 1.

[0105] Table 1

[0106] All-ionic liquid extraction system Vanadium concentration in vanadium electrolyte (mol / L) [[TOMA] [EHEHP]: [C4mim] [NTf2] = 2:8] 1.72 [[TOMA][DEHP]: [C4mim][NTf2] = 2:8] 1.71 [[P 4444 ][EHEHP]-[C4mim][NTf2] = 2:8 1.71 [[P 4444 ][DEHP]:[C4mim][NTf2]=2:8]]> 1.72

[0107] As can be seen from Examples 1-4 and Table 1, the vanadium electrolyte prepared in the present application has a vanadium concentration greater than 1.7 mol / L.

[0108] Finally, it should be noted that the above specific embodiments are merely used to illustrate the technical solutions of the present application but not to limit the present application. Although the present application has been described in detail with reference to the examples, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or replaced equivalently without departing from the spirit and scope of the technical solutions of the present application, and all of them should be covered in the scope of the claims of the present application.

Claims

1. A fully ionic liquid extraction system, characterized in that, The all-ionic liquid extraction system includes an extractant and a diluent; the extractant is [TOMA][EHEHP], [TOMA][DEHP], [P] 4444 [EHEHP] and [P] 4444 A mixture of one or two of [DEHP] in any proportion; the diluent is [C n mim][NTf2]、[C n mim][PF6] and [C n A mixture of one or two of the following in any proportion: [mim][SbF6], wherein n = 2 to 8.

2. The all-ionic liquid extraction system according to claim 1, characterized in that, The volume ratio of extractant to diluent is 1:3 to 5.

3. The all-ionic liquid extraction system according to claim 1, characterized in that, The preparation method of the extractant includes the following steps: (1) Dissolve sodium hydroxide and methyltrioctylammonium chloride or tetrabutylphosphine bromide in isopropanol, mix thoroughly, stir at 30-40 °C for 24-26 h, filter, and obtain [TOMA][OH] intermediate or [P 4444 [OH] intermediate; (2) Dissolve 2-ethylhexyl phosphate mono-2-ethylhexyl ester or di(2-ethylhexyl) phosphate in isopropanol, and add [TOMA][OH] intermediate or [P] to it. 4444 The [OH] intermediate was stirred at 30–40 °C for 24–26 h, and isopropanol was removed by rotary evaporation to obtain [TOMA][EHEHP], [TOMA][DEHP], and [P], respectively. 4444 [EHEHP] or [P] 4444 ][DEHP].

4. A method for preparing vanadium electrolyte using a short-process approach based on an all-ionic liquid extraction system, characterized in that, The method using the all-ionic liquid extraction system according to claim 1, 2, or 3 comprises the following steps: (1) Add sulfuric acid and leaching aid to vanadium-containing material, react for 4-12 h, filter to obtain vanadium-containing mother liquor; (2) Add the vanadium-containing mother liquor to the all-ionic liquid extraction system to obtain the vanadium extraction ionic liquid; (3) Add sulfuric acid to the vanadium extraction ionic liquid for back extraction to obtain vanadium-containing acid solution; (4) Add sulfuric acid to the vanadium-containing acid solution again or directly evaporate and concentrate to obtain vanadium electrolyte.

5. The method according to claim 4, characterized in that: In step (1), the leaching aid is one or a mixture of two of the following in any proportion: ammonium sulfate, calcium fluoride, and sodium tripolyphosphate.

6. The method according to claim 5, characterized in that: In step (1), the amount of leaching aid used is 1 to 5% of the mass of the vanadium-containing material.

7. The method according to claim 4, characterized in that: In step (1), the concentration of sulfuric acid is 10-25% by mass percentage.

8. The method according to claim 4, characterized in that: In step (2), the volume ratio of vanadium-containing mother liquor to all-ionic liquid extraction system is 1:0.2-2.

9. The method according to claim 4, characterized in that: In step (3), the volume ratio of vanadium extraction ionic liquid to sulfuric acid is 1 to 5:1; the back-extraction is performed at 20 to 80 °C for 10 to 60 min; and the concentration of sulfuric acid is 5 to 25% by mass percentage.

10. The method according to claim 4, characterized in that: In step (4), sulfuric acid is added again to adjust the vanadium concentration in the resulting vanadium electrolyte to 1.5–2.0 mol / L; the concentration of the sulfuric acid is 5–25% by mass percentage.

Images