Process for extracting gallium from vanadium slag based on microwave-enhanced selective precipitation-ion liquid circulation

Abstract

The application discloses a kind of vanadium residue extraction gallium processes based on microwave intensification selective precipitation-ion liquid circulation, belong to metal resource recovery technical field.The present application provides a kind of vanadium residue extraction gallium processes based on microwave intensification selective precipitation-ion liquid circulation to solve the problems such as high energy consumption, low selectivity of existing process, comprising: the gallium-containing vanadium residue is roasted under microwave, then low eutectic solvent is added to leaching, the obtained gallium-containing leaching solution is extracted with hydrophobic ionic liquid as extractant, the obtained gallium-loaded ionic liquid phase is used as electrolyte, and constant potential electrodeposition is carried out to obtain metallic gallium.The present application uses microwave to rapidly and selectively heat the gallium-containing mineral phase, which allows gallium to concentrate at the easily dissociated grain boundaries, then mild leaching is carried out by low eutectic solvent, and green recovery of gallium is achieved by ionic liquid electrodeposition, solving the problems of high temperature and high pressure, high pollution in traditional process.

Description

Technical Field

[0001] This invention belongs to the field of metal resource recycling technology, specifically relating to a gallium extraction process from vanadium slag based on microwave-enhanced selective precipitation-ionic liquid circulation. It is particularly suitable for the resource utilization of gallium in vanadium slag or vanadium extraction tailings with complex multimetallic systems generated during the smelting of vanadium-titanium magnetite. Background Technology

[0002] Gallium (Ga), a strategic rare metal, is associated with vanadium-titanium magnetite, primarily concentrated in vanadium extraction tailings. Existing technologies for extracting gallium from vanadium tailings mainly fall into two categories: pyrometallurgical chlorination roasting and hydrometallurgical pressure leaching. Traditional chlorination roasting (as described in CN88107424.1) typically involves adding chloride salts at high temperatures to volatilize gallium, which suffers from the high corrosiveness of chlorine gas, high tail gas treatment costs, and large equipment investment. Hydrometallurgical processes, such as the "method for extracting gallium from vanadium tailings by alkaline roasting," can achieve high leaching rates, but require high pressure (0.2~2.5MPa) and high temperature (120~250℃), consuming large amounts of alkaline solution and resulting in high wastewater treatment pressure.

[0003] In recent years, although some studies have proposed the use of vacuum melting-chlorination method to extract vanadium and gallium (such as CN202511032795), the core still relies on chlorine chlorination, and the selective separation of gallium requires a complex molecular sieve adsorption system, which is a long process.

[0004] It is evident that existing processes for extracting gallium from vanadium tailings suffer from drawbacks such as high energy consumption, high reagent consumption, and insufficient selectivity. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a gallium extraction process from vanadium slag based on microwave selective precipitation-ionic liquid circulation. This process utilizes microwaves to rapidly and selectively heat the gallium-containing mineral phase, causing gallium to accumulate at easily dissociated grain boundaries. Subsequently, it is gently leached using a eutectic solvent (DES) and achieves green gallium recovery through ionic liquid electrodeposition, thus solving the problems of high temperature, high pressure, and high pollution associated with traditional processes.

[0006] To achieve the above objectives, the present invention provides a gallium extraction process from vanadium slag based on microwave-enhanced selective precipitation-ionic liquid cycle, which includes the following steps:

[0007] A. Microwave selective pretreatment: Gallium-vanadium slag and silicon carbide are mixed evenly at a mass ratio of 100:0~3, and then roasted under microwave power of 2~5kW / kg and temperature of 600~850℃. The microwave utilizes the different dielectric properties of the iron-rich phase and gallium-containing silicate phase in the vanadium slag to induce microcracks in the gallium-containing mineral phase and selectively enrich it at easily dissociated grain boundaries, and then cools.

[0008] B. Euclidean solvent leaching: The microwave-pretreated material is added to an eutectic solvent for leaching. The solid-liquid ratio is 1kg:5~10L, the leaching temperature is 60~120℃, gallium oxide is selectively dissolved, and solid-liquid separation is performed to obtain gallium-containing leachate. The eutectic solvent is a mixture of hydrogen bond acceptor solvent and hydrogen bond donor solvent in a molar ratio of 1:2~4.

[0009] C. Ionic liquid back-extraction and enrichment: Using a hydrophobic ionic liquid as the extractant, the pH of the gallium-containing leaching aqueous phase is adjusted to 2.0~4.0. The gallium-containing leaching solution is mixed with the hydrophobic ionic liquid, and the gallium complex is extracted and separated by utilizing the affinity of the ionic liquid for the gallium complex to obtain the gallium-loaded ionic liquid phase.

[0010] D. Electrodeposition recovery of metallic gallium: Using gallium-loaded ionic liquid phase as electrolyte, constant potential electrodeposition is performed to obtain metallic gallium.

[0011] In the above-mentioned gallium extraction process from vanadium slag based on microwave-enhanced selective precipitation-ionic liquid circulation, in step A, when the mass ratio of gallium-vanadium slag to silicon carbide is 100:0~0.5, the microwave power is controlled at 4~5kW / kg and the temperature at 750~850℃.

[0012] In the above-mentioned gallium extraction process from vanadium slag based on microwave-enhanced selective precipitation-ionic liquid circulation, in step A, the particle size of the gallium-vanadium slag is 100~300 mesh undersize.

[0013] In the above-mentioned process for gallium extraction from vanadium slag based on microwave-enhanced selective precipitation-ionic liquid circulation, step A of the gallium-containing vanadium slag contains 0.012~0.050wt% Ga.

[0014] In the above-mentioned gallium extraction process from vanadium slag based on microwave-enhanced selective precipitation-ionic liquid circulation, in step A, the gallium-containing vanadium slag contains 5.5~12.5wt% V2O5, 20~55wt% FeO, and 10~20wt% SiO2.

[0015] In the above-mentioned process for gallium extraction from vanadium slag based on microwave-enhanced selective precipitation-ionic liquid circulation, the calcination time in step A is 30~90 min.

[0016] In the above-mentioned vanadium slag gallium extraction process based on microwave-enhanced selective precipitation-ionic liquid circulation, in step B, the hydrogen bond acceptor solvent is selected from at least one of choline chloride, betaine, tetraethylammonium chloride, and amino acids.

[0017] In the above-mentioned vanadium slag gallium extraction process based on microwave-enhanced selective precipitation-ionic liquid circulation, in step B, the hydrogen bond donor solvent is selected from at least one of ethylene glycol, glycerol, oxalic acid, diethanolamine, lactic acid, urea, and citric acid.

[0018] In the above-mentioned vanadium slag gallium extraction process based on microwave-enhanced selective precipitation-ionic liquid circulation, the leaching time in step B is 2-4 hours.

[0019] In the above-mentioned vanadium slag gallium extraction process based on microwave-enhanced selective precipitation-ionic liquid cycle, the hydrophobic ionic liquid in step C is [Bmim][PF6] or [C8mim][NTf2].

[0020] In the aforementioned process for gallium extraction from vanadium slag based on microwave-enhanced selective precipitation-ionic liquid circulation, step C involves adjusting the pH using dilute hydrochloric acid.

[0021] In the above-mentioned vanadium slag gallium extraction process based on microwave-enhanced selective precipitation-ionic liquid circulation, in step C, the extraction ratio O / A = 1:1~3.

[0022] In the above-mentioned process for gallium extraction from vanadium slag based on microwave-enhanced selective precipitation-ionic liquid circulation, step C involves extraction and separation at a temperature of 25-40℃ with oscillation for 10-20 minutes.

[0023] In the above-mentioned vanadium slag gallium extraction process based on microwave-enhanced selective precipitation-ionic liquid circulation, step C employs multi-stage countercurrent extraction with 3 to 5 extraction stages; the extraction time for each stage is controlled at 10 to 20 minutes, the temperature is maintained at 25 to 40°C, and the ratio is fixed at O / A = 1:1 to 3.

[0024] In the above-mentioned vanadium slag gallium extraction process based on microwave-enhanced selective precipitation-ionic liquid circulation, in step C, the extraction time for each stage is controlled at 10-20 minutes, the temperature is maintained at 25-40℃, and the ratio is fixed at O / A=1:1-3.

[0025] In the above-mentioned vanadium slag gallium extraction process based on microwave-enhanced selective precipitation-ionic liquid cycle, the electrodeposition temperature in step D is 25~60℃.

[0026] In the above-mentioned vanadium slag gallium extraction process based on microwave-enhanced selective precipitation-ionic liquid circulation, the electrodeposition time in step D is 1~6 hours.

[0027] In the above-mentioned vanadium slag gallium extraction process based on microwave-enhanced selective precipitation-ionic liquid circulation, in step D, the electrodeposition anode is selected from stainless steel 316, stainless steel 316L or platinum, and the anode is selected from stainless steel 316, stainless steel 316L, aluminum, glassy carbon or copper.

[0028] In the above-mentioned vanadium slag gallium extraction process based on microwave-enhanced selective precipitation-ionic liquid cycle, in step D, the constant potential for electrodeposition is -1.0V to -1.5V (vs. Ag / AgCl).

[0029] In the aforementioned process for gallium extraction from vanadium slag based on microwave-enhanced selective precipitation-ionic liquid circulation, gallium metal is deposited on the cathode surface in step D.

[0030] In the above-mentioned vanadium slag gallium extraction process based on microwave-enhanced selective precipitation-ionic liquid recycling, in step D, the electrodeposited ionic liquid is purified and recycled back to step C for use.

[0031] In this invention, "aqueous phase" refers to a solution using "eutectic solvent" as the solvent, while "organic phase" refers to a solution using "hydrophobic ionic liquid" as the solvent.

[0032] The beneficial effects of this invention are:

[0033] This invention first utilizes microwaves to rapidly and selectively heat gallium-containing mineral phases, enriching gallium at easily dissociatable grain boundaries. Subsequently, it employs a gentle leaching process using a eutectic solvent (DES) to selectively dissolve gallium oxides, achieving a gallium leaching rate of over 88%. Furthermore, it achieves green gallium recovery through ionic liquid electrodeposition, with a gallium extraction rate of over 95%, an electrodeposited gallium purity of over 99%, and a yield of over 80%. This invention solves the problems of high temperature, high pressure, and high pollution associated with traditional processes, and realizes the efficient recovery of trace gallium from gallium-vanadium slag. Detailed Implementation

[0034] Specifically, a process for gallium extraction from vanadium slag based on microwave-enhanced selective precipitation-ionic liquid recycling includes the following steps:

[0035] A. Microwave selective pretreatment: After crushing gallium-vanadium slag to a certain particle size, mix it with silicon carbide at a mass ratio of 100:0~3 and place it in a microwave roasting furnace for pretreatment. Control the microwave power density to be 2~5kW / kg, the temperature to be 600~850℃, and the holding time to be 30~90min. Utilize the different dielectric properties of the iron-rich phase and the gallium-containing silicate phase in the vanadium slag by microwave to promote the formation of microcracks in the gallium-containing mineral phase and selective enrichment at easily dissociated grain boundaries.

[0036] B. Eutectic solvent leaching: The microwave-pretreated material is added to a prepared eutectic solvent (DES) for leaching. The eutectic solvent is a mixture of hydrogen bond acceptors (such as choline chloride) and hydrogen bond donors (such as ethylene glycol, urea, citric acid, etc.) in a molar ratio of 1:2~4. The leaching temperature is controlled at 60~120℃, the leaching time is 2~4h, and the solid-liquid ratio is 1kg:5~10L. During this process, DES selectively dissolves gallium oxides, but has poor solubility for impurities such as iron and silicon.

[0037] C. Ionic liquid back-extraction and enrichment: The pH of the aqueous phase of the gallium-containing DES leaching solution is adjusted to 2.0~4.0 using dilute hydrochloric acid, and then contacted with a hydrophobic ionic liquid (such as [Bmim][PF6] or [C8mim][NTf2]). The ionic liquid is used to extract and separate gallium complexes by utilizing its affinity for gallium to obtain a gallium-loaded ionic liquid phase.

[0038] D. Electrodeposition recovery of metallic gallium: Using gallium-loaded ionic liquid phase as electrolyte, constant potential electrodeposition is performed to obtain metallic gallium.

[0039] During the pretreatment of this invention, it is possible to choose not to add or to add only a small amount of silicon carbide. In this case, it is necessary to increase the calcination power and temperature. According to the experiment, in step A, when the mass ratio of gallium-vanadium slag to silicon carbide is 100:0~0.5, the microwave power should be controlled at 4~5kW / kg and the temperature at 750~850℃ to ensure the yield.

[0040] In step A of this invention, the gallium-vanadium-containing slag has a particle size of 100-300 mesh sieve underflow. In step A of this invention, the gallium-vanadium-containing slag is a conventional vanadium slag in the art, which generally contains trace amounts of gallium, Ga 0.012-0.050 wt%; in addition, it also contains V₂O 55.5-12.5 wt%, FeO 20-55 wt%, and SiO₂ 10-20 wt%.

[0041] In step B of this invention, the hydrogen bond acceptor solvent is selected from at least one of choline chloride, betaine, tetraethylammonium chloride, and amino acids; the hydrogen bond donor solvent is selected from at least one of ethylene glycol, glycerol, oxalic acid, diethanolamine, lactic acid, urea, and citric acid. In some cases, the hydrogen bond acceptor solvent and the hydrogen bond donor solvent are mixed and are solid at room temperature, but when mixed in a specific molar ratio and heated to a certain temperature, they form a homogeneous liquid with a melting point much lower than that of each component, which is called a "eutectic solvent." Under this "eutectic solvent," selective dissolution of gallium oxides can be achieved.

[0042] In step B of this invention, the leaching time is 2-4 hours.

[0043] In step C of this invention, the extraction ratio O / A is 1:1~3; the extraction separation is carried out at a temperature of 25~40℃ with shaking for 10~20 minutes.

[0044] In step C of this invention, multi-stage countercurrent extraction is preferably used, with 3 to 5 extraction stages; the extraction time for each stage is controlled at 10 to 20 minutes, the temperature is maintained at 25 to 40°C, and the ratio is fixed at O / A = 1:1 to 3 to ensure that the gallium extraction rate is greater than 95%.

[0045] Multi-stage countercurrent extraction is a standard extraction process in this field. Taking three-stage countercurrent extraction as an example: First, the pH of the gallium-containing leaching solution in the aqueous phase is adjusted to 2-4 with dilute hydrochloric acid. Then, fresh hydrophobic ionic liquid [C8mim][NTf2] is added to the first-stage extractor at a ratio of O / A = 1:1-3. The mixture is stirred and mixed for 10-20 minutes to ensure sufficient contact between the two phases. After standing and phase separation, the raffinate from the first stage is transferred to the second stage and mixed with the organic phase from the third stage for extraction. The raffinate from the second stage is then transferred to the third stage and mixed with the fresh organic phase for extraction. Simultaneously, the loaded organic phase from the third stage is returned to the second stage, and the loaded organic phase from the second stage is returned to the first stage, forming a countercurrent cycle where the aqueous phase flows forward and the organic phase flows backward. The extraction time for each stage is controlled at 10-20 minutes, the temperature is maintained at 25-40℃, and the ratio is fixed at O / A = 1:1-3. After 5-10 cycles to reach steady state, the high-concentration loaded organic phase is continuously collected from the first stage and sent for back-extraction, while the low-concentration raffinate is discharged from the third stage. Throughout the process, pH is adjusted only before mixing the aqueous phase to avoid measurement in the mixed system and ensure accuracy. Multi-stage countercurrent extraction does not discard all liquid after each extraction; instead, it is a cyclical process where "the aqueous phase flows sequentially to the next stage, and the organic phase flows sequentially back to the previous stage." The organic phase output from each stage is the input for the next stage, and the aqueous phase output from each stage is the input for the previous stage. Through this interconnection, utilizing the concentration gradient driving force, solvent consumption is minimized and separation efficiency is maximized. (See Table 1).

[0046] Table 1. Three-stage countercurrent extraction process

[0047]

[0048] In step D of this invention, the electrodeposition temperature is 25~60℃. The electrodeposition time in step D is 1~6 hours. In step D, the anode for electrodeposition is selected from stainless steel 316, stainless steel 316L, or platinum; the cathode is selected from stainless steel 316, stainless steel 316L, aluminum, glassy carbon, or copper; preferably, both the anode and cathode are stainless steel 316 or stainless steel 316L. In step D, the constant potential for electrodeposition is -1.0V~-1.5V (vs. Ag / AgCl). In step D, metallic gallium is deposited on the cathode surface.

[0049] In step D of this invention, the electrodeposited ionic liquid is purified and recycled back to step C for use. Purification of the electrodeposited ionic liquid can be carried out using conventional methods in the art, such as washing and regenerating the electrodeposition residue. Washing operation: After electrodeposition, the gallium-loaded ionic liquid phase (i.e., the electrodeposition residue) is separated from the deposited metallic gallium. The residue is transferred to a separatory funnel or washing vessel, and an equal volume of deionized water or dilute hydrochloric acid solution (pH≈2~3) is added. The mixture is shaken and washed for 5~10 minutes, allowed to stand for phase separation, and repeated 2~3 times to remove gallium salts, trace impurities, and residual electrolyte components from the residue. The washed ionic liquid phase is then subjected to vacuum distillation or vacuum drying to remove residual water. Regeneration operation: The washed ionic liquid is mixed with fresh extractant in a certain ratio (e.g., regenerator:fresh agent = 4~9:1). If necessary, a small amount of dilute hydrochloric acid is added to adjust to the target pH value (e.g., 3.0). After stirring and homogenization, the mixture can be returned to the extraction process for recycling. If the extraction efficiency of ionic liquids decreases significantly (e.g., below 80% of the initial value), activated carbon adsorption, ion exchange resin treatment, or centrifugation can be used to remove accumulated impurities and restore its extraction activity.

[0050] The present invention will be further described in detail below through embodiments, but the scope of protection of the present invention is not limited to the embodiments described herein.

[0051] Example 1

[0052] The vanadium slag produced after smelting vanadium-titanium magnetite from a certain place is used as raw material. Its main components, by weight percentage, are: V2O5 12.5%, FeO 35.2%, SiO2 18.6%, and Ga 0.025%.

[0053] 1. Microwave pretreatment: Take 1000g of the above vanadium slag, crush it to a particle size of less than 0.5mm, and add 20g of silicon carbide (SiC) and mix evenly. Place the mixture in a microwave muffle furnace and calcine it for 60 minutes at a microwave power of 3kW / kg and a temperature of 750℃. After natural cooling, remove it, and obvious microcracks can be seen on the surface of the material.

[0054] 2. Eutectic solvent (DES) leaching: A eutectic solvent with a molar ratio of choline chloride to ethylene glycol of 1:3 was prepared. The microwave-treated vanadium slag was added to a reactor, and the aforementioned eutectic solvent was added at a solid-liquid ratio of 1 kg: 8 L. Leaching was carried out at 100°C with stirring for 3 hours. After leaching, the mixture was filtered and separated to obtain a gallium-containing leaching solution and leaching residue. Testing showed that the gallium leaching rate reached 92.5%, while the iron leaching rate was less than 5%.

[0055] 3. Ionic liquid extraction: The hydrophobic ionic liquid [C8mim][NTf2] was used as the extractant. The pH of the gallium-containing leaching solution was adjusted to 3.0 with dilute hydrochloric acid. The gallium-containing leaching solution and the hydrophobic ionic liquid were mixed at a ratio of O / A = 1:2. Three-stage countercurrent extraction was performed, with each stage of extraction involving shaking for 15 minutes. The temperature was maintained at 25°C, and the ratio was kept constant at O / A = 1:2. After standing and phase separation, the gallium-loaded ionic liquid phase was obtained, and the total gallium extraction rate reached over 98%.

[0056] 4. Electrodeposition: The gallium-loaded ionic liquid phase is transferred to an electrolytic cell. A platinum sheet is used as the anode, and 316L stainless steel as the cathode. Electrodeposition is performed for 4 hours at 50°C and a constant potential of -1.2V (vs. Ag / AgCl). Silvery-white metallic gallium is deposited on the cathode surface. After stripping, the metallic gallium product is obtained with a purity of 99.5% and a yield of 86.7%. The electrodeposition residue can be recycled back to step 3 after washing and regeneration.

[0057] Example 2

[0058] This embodiment focuses on gallium extraction experiments on vanadium extraction tailings with low gallium content (Ga 0.012%). The remaining steps are basically the same as in Embodiment 1.

[0059] The difference lies in the fact that SiC was not added during the microwave pretreatment stage, but the microwave power density was increased to 4.5 kW / kg and the temperature was raised to 800℃. The final gallium leaching rate reached 88.3%, the extraction rate 97.2%, the electrolytic gallium purity 99.2%, and the yield 82.3%.

[0060] Comparative Example 1

[0061] The vanadium slag, which was treated in the same way as in Example 1, was processed using the traditional "alkaline roasting-pressure leaching method".

[0062] The tailings were mixed with lime and sodium hydroxide at a mass ratio of 1:1:2.5, pressed into briquettes, and calcined at 900℃ for 3 hours. Then, leaching was performed with NaOH aqueous solution at a solid-liquid ratio of 1:4, 1.5 MPa, and 200℃. The final gallium leaching rate was 91.0%, but the process suffered from high alkali consumption, demanding leaching equipment requirements, and high wastewater treatment costs. In particular, during the pressurization process, impurities such as silicon and aluminum ions entered the solution, affecting product purity and significantly reducing extraction rate, purity, and yield.

[0063] The comparison shows that, while achieving similar or even higher leaching rates, the present invention uses milder reaction conditions (atmospheric pressure, 100°C) and significantly reduces emissions of waste gas, wastewater, and solid waste through closed-loop circulation of DES and ionic liquid.

Claims

1. A process for gallium extraction from vanadium slag based on microwave-enhanced selective precipitation-ionic liquid recycling, characterized in that: Includes the following steps: A. Microwave selective pretreatment: Gallium-vanadium slag and silicon carbide are mixed evenly at a mass ratio of 100:0~3, and then roasted under microwave power of 2~5kW / kg and temperature of 600~850℃. The microwave utilizes the different dielectric properties of the iron-rich phase and gallium-containing silicate phase in the vanadium slag to induce microcracks in the gallium-containing mineral phase and selectively enrich it at easily dissociated grain boundaries, and then cools. B. Euclidean solvent leaching: The microwave-pretreated material is added to an eutectic solvent for leaching. The solid-liquid ratio is 1kg:5~10L, the leaching temperature is 60~120℃, gallium oxide is selectively dissolved, and solid-liquid separation is performed to obtain gallium-containing leachate. The eutectic solvent is a mixture of hydrogen bond acceptor solvent and hydrogen bond donor solvent in a molar ratio of 1:2~4. C. Ionic liquid back-extraction and enrichment: Using a hydrophobic ionic liquid as the extractant, the pH of the gallium-containing leaching aqueous phase is adjusted to 2.0~4.

0. The gallium-containing leaching solution is mixed with the hydrophobic ionic liquid, and the gallium complex is extracted and separated by utilizing the affinity of the ionic liquid for the gallium complex to obtain the gallium-loaded ionic liquid phase. D. Electrodeposition recovery of metallic gallium: Using gallium-loaded ionic liquid phase as electrolyte, constant potential electrodeposition is performed to obtain metallic gallium.

2. The vanadium slag gallium extraction process based on microwave-enhanced selective precipitation-ionic liquid circulation according to claim 1, characterized in that: In step A, when the mass ratio of gallium-vanadium slag to silicon carbide is 100:0~0.5, the microwave power is controlled at 4~5kW / kg and the temperature at 750~850℃.

3. The vanadium slag gallium extraction process based on microwave-enhanced selective precipitation-ionic liquid circulation according to claim 1, characterized in that: At least one of the following must be met: In step A, the particle size of the gallium-vanadium-containing slag is 100-300 mesh sieve undersize. In step A, the gallium-vanadium slag contains 0.012~0.050 wt% Ga. In step A, the gallium-vanadium slag contains 5.5~12.5 wt% V2O5, 20~55 wt% FeO, and 10~20 wt% SiO2. In step A, the roasting time is 30~90 minutes.

4. The vanadium slag gallium extraction process based on microwave-enhanced selective precipitation-ionic liquid circulation according to claim 1, characterized in that: At least one of the following must be met: In step B, the hydrogen bond acceptor solvent is selected from at least one of choline chloride, betaine, tetraethylammonium chloride, and amino acids; In step B, the hydrogen bond donor solvent is selected from at least one of ethylene glycol, glycerol, oxalic acid, diethanolamine, lactic acid, urea, and citric acid.

5. The vanadium slag gallium extraction process based on microwave-enhanced selective precipitation-ionic liquid circulation according to claim 1, characterized in that: In step B, the leaching time is 2-4 hours.

6. The gallium extraction process from vanadium slag based on microwave-enhanced selective precipitation-ionic liquid circulation according to claim 1, characterized in that: In step C, the hydrophobic ionic liquid is [Bmim][PF6] or [C8mim][NTf2].

7. The vanadium slag gallium extraction process based on microwave-enhanced selective precipitation-ionic liquid circulation according to claim 1, characterized in that: At least one of the following must be met: In step C, dilute hydrochloric acid is used to adjust the pH. In step C, the extraction ratio O / A is 1:1~3; In step C, the extraction and separation is carried out by shaking at a temperature of 25~40℃ for 10~20 minutes.

8. The vanadium slag gallium extraction process based on microwave-enhanced selective precipitation-ionic liquid circulation according to claim 1, characterized in that: In step C, multi-stage countercurrent extraction is used, with 3 to 5 extraction stages; preferably, the extraction time for each stage is controlled at 10 to 20 minutes, the temperature is maintained at 25 to 40°C, and the ratio of O / A is fixed at 1:1 to 3.

9. The vanadium slag gallium extraction process based on microwave-enhanced selective precipitation-ionic liquid circulation according to claim 1, characterized in that: In step D, the electrodeposition temperature is 25~60℃; In step D, the electrodeposition time is 1 to 6 hours; In step D, the electrodeposited anode is selected from stainless steel 316, stainless steel 316L or platinum, and the anode is selected from stainless steel 316, stainless steel 316L, aluminum, glassy carbon or copper. In step D, the electrodeposition potential is constant at -1.0V to -1.5V (vs. Ag / AgCl). In step D, metallic gallium is deposited on the cathode surface.

10. The vanadium slag gallium extraction process based on microwave-enhanced selective precipitation-ionic liquid circulation according to claim 1, characterized in that: In step D, the electrodeposited ionic liquid is purified and recycled back to step C for use.

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