Method for extracting gallium from gallium arsenide leaching solution in hydrogen fluoride and nitric acid mixed system

Abstract

This application provides a method for extracting gallium from gallium arsenide leaching solution in a mixed system of hydrofluoric acid and nitric acid, belonging to the field of rare metal metallurgy technology. The method includes the following steps: adding sodium salt to the gallium arsenide leaching solution to obtain a fluoride-containing filter residue and a defluorinated filtrate; adjusting the pH of the defluorinated filtrate to 5.0-5.5 using liquid alkali to obtain a gallium-containing filter residue; acid washing the fluoride-containing filter residue to obtain a first acid washing solution, which is then mixed with the gallium arsenide leaching solution from step S1; dissolving the gallium-containing filter residue with a strong acid solution to obtain a gallium-containing solution; adding sodium sulfide to remove arsenic to obtain an arsenic-containing filter residue and an arsenic-removed filtrate; adjusting the pH of the arsenic-removed filtrate to greater than 12 using liquid alkali, filtering, and obtaining a gallium-rich filtrate; and performing electrodeposition to obtain gallium metal. This invention utilizes the amphoteric nature of gallium hydroxide to transfer gallium from a complex leaching solution system to a single system for gallium extraction, greatly reducing gallium loss during the removal of arsenic and other impurities.

Description

Technical Field

[0001] This invention relates to the field of rare metal metallurgy, specifically to a method for extracting gallium from gallium arsenide leaching solution under a mixed system of hydrofluoric acid and nitric acid. Background Technology

[0002] Gallium (Ga) is one of the important rare and dispersed metals. Gallium arsenide (GaAs) has become one of the most important compound semiconductor materials due to its high frequency, high electron mobility, low noise, high output power, low power consumption, high efficiency, good linearity, and low distortion. In my country, gallium consumption areas include semiconductors and optoelectronic materials, solar cells, alloys, medical devices, and magnetic materials. The semiconductor industry accounts for 80% to 85% of total gallium consumption, making it the main application area for gallium. With the rapid development of downstream gallium application industries, especially the semiconductor and solar cell industries, the demand for gallium is expected to grow steadily in the future. Years of economic development have resulted in a large amount of gallium-containing waste from semiconductors and other sources. Currently, GaAs waste is the largest category of gallium-containing electronic waste to be recycled, mainly including GaAs thin-film solar cell waste and wastewater generated during the fabrication of GaAs chips in the semiconductor industry.

[0003] The presence of asphalt (As) in GaAs poses an environmental threat and is difficult to separate, making direct recycling challenging. Currently, the main recycling processes are hydrometallurgy, pyrometallurgy, and bioleaching. Pyrometallurgy's development is limited by high equipment and energy costs, while bioleaching remains uncommon due to its low leaching efficiency. Chinese patent CN111440955B discloses a method for extracting gallium from gallium-containing smelting slag, using alkaline solution and calcium source to remove impurities, followed by electrolysis to obtain high-purity gallium. However, gallium smelting slag also contains a large amount of fluoride ions, which combine with gallium ions and, to some extent, hinder the formation of gallium hydroxide precipitate, affecting the gallium ion extraction rate. Furthermore, the removal of metal ion impurities such as As also leads to gallium ion loss, thus affecting the gallium ion recovery rate. Summary of the Invention

[0004] In view of the technical problems existing in the background art, this application provides a method for extracting gallium from gallium arsenide leaching solution under a mixed system of hydrofluoric acid and nitric acid, aiming to solve the technical problem of low gallium recovery rate in the process of wet leaching and recycling gallium.

[0005] In a first aspect, embodiments of this application provide a method for extracting gallium from a gallium arsenide leaching solution in a mixed system of hydrofluoric acid and nitric acid, comprising the following steps: S1. Add sodium salt to gallium arsenide leaching solution, react and filter to obtain fluorine-containing filter residue and defluorinated filtrate; S2. The pH of the defluorination filtrate is adjusted to 5.0~5.5 using liquid alkali, and after stirring and reaction, it is filtered to obtain gallium-containing filter residue; The fluorine-containing filter residue is acid-washed to obtain a first acid washing solution, which is then mixed with the gallium arsenide leaching solution in step S1. S3. Dissolve the gallium-containing filter residue with a strong acid solution to obtain a gallium-containing solution. Add sodium sulfide to the gallium-containing solution to remove arsenic. After filtration, obtain arsenic-containing filter residue and arsenic-removed filtrate. S4. Adjust the pH of the arsenic-removed filtrate to be greater than 12 using liquid alkali, and then filter to obtain gallium-rich filtrate. S5. Electrodeposit gallium-rich filtrate to obtain gallium metal.

[0006] In some embodiments, the molar ratio of sodium salt to fluoride ions in gallium arsenide leaching solution in step S1 is (2~3):1; Sodium salts include at least one of sodium chloride, sodium carbonate, sodium sulfate, and sodium bicarbonate.

[0007] In some embodiments, the concentration of the sulfuric acid solution used for pickling in step S2 is 0.1~2 mol / L; The volume ratio of sulfuric acid solution to fluoride-containing filter residue is (2~3):1.

[0008] In some embodiments, the strong acid solution in step S3 includes a sulfuric acid solution; The volume ratio of the strong acid solution to the gallium-containing filter residue is (1~4):1.

[0009] In some embodiments, the molar ratio of sodium sulfide to arsenic ions in the gallium-containing solution in step S3 is (2~5):1.

[0010] In some embodiments, the concentration of liquid alkali in step S4 is 100~150g / L.

[0011] In some embodiments, the electrodeposition voltage in step S5 is 2~5V.

[0012] In some embodiments, in step S3, the arsenic-containing filter residue is acid-washed to obtain a second acid washing solution, which is then mixed with a gallium-containing solution.

[0013] In some embodiments, the electrolyte obtained after electrodeposition is mixed with the arsenic removal filtrate.

[0014] In some embodiments, the gallium arsenide leaching solution includes SiO3. 2- 7~25g / L, F - 30~100g / L, Ga 2+ 10~60g / L, AsO4 3- 10~60g / L, NO3 - 120~350g / L, Fe 3+<1g / L.

[0015] The advantages of this application, which differ from existing technical solutions, include: This invention first uses sodium salt to remove fluoride ions, thus eliminating the interference of fluorosilicate ions on subsequent gallium extraction. Then, it uses an alkaline solution to precipitate gallium ions and remove nitrate ions. Next, it dissolves the gallium-containing filter residue with sulfuric acid solution, then adds sodium sulfide to remove arsenic, obtaining a relatively pure arsenic-free filtrate. The pH is then adjusted to above 12 to remove impurities such as iron ions, resulting in a gallium-rich filtrate. Finally, the gallium-rich filtrate is electrodeposited to obtain gallium metal. This invention utilizes the amphoteric nature of gallium hydroxide to transfer gallium from a complex leaching solution system to a single system for gallium extraction, significantly reducing gallium loss during arsenic and other impurity removal. The process is simple, improves gallium metal recovery, and greatly reduces operating costs in industrial production.

[0016] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of this application, the accompanying drawings used in this application will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort.

[0018] Figure 1 This is a process flow diagram of an embodiment of this application. Detailed Implementation

[0019] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0021] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0022] Gallium smelting slag also contains a large amount of fluoride ions, which can combine with gallium ions and, to some extent, hinder the formation of gallium hydroxide precipitate, thus affecting the gallium ion extraction rate. Furthermore, the removal of metal ion impurities such as As can also lead to the loss of gallium ions, thereby affecting the gallium ion recovery rate.

[0023] To address the technical problem of low gallium recovery rate in the wet leaching process for gallium recovery, this application provides a method for extracting gallium from gallium arsenide leaching solution using a mixed system of hydrofluoric acid and nitric acid, such as... Figure 1 As shown, it includes the following steps: S1. Add sodium salt to the gallium arsenide leaching solution, and after the reaction, filter to obtain fluorine-containing filter residue and defluorinated filtrate. Sodium salt can react with fluorosilicate ions to form sodium fluorosilicate precipitate, and the reaction equation is shown in equation (1) below. If fluorosilicate ions are not preferentially removed, they will hinder the formation of gallium hydroxide precipitate by gallium ions and hydroxide ions. Therefore, sodium salt is added in the first step to remove the interference of fluorosilicate ions on subsequent processes.

[0024] H2SiF6+2Na→Na2SiF6↓+2HCl↑(1).

[0025] S2. The pH of the defluorination filtrate is adjusted to 5.0-5.5 using liquid alkali. After stirring and reacting, the solution is filtered to obtain gallium-containing filter residue and gallium-precipitated liquid. Gallium ions form gallium hydroxide precipitate under pH conditions of 5.0-5.5, which can remove nitrate ions from the gallium arsenide leaching solution.

[0026] The fluorine-containing filter residue is acid-washed and filtered to obtain a first acid washing solution and acid-washed fluorine-removed residue. The first acid washing solution is mixed with the gallium arsenide leaching solution in step S1. During the precipitation process, sodium hexafluorosilicate will carry some gallium ions. The fluorine-containing filter residue is acid-washed. Sodium hexafluorosilicate is insoluble in acid, which can dissolve the gallium ions in it. The gallium-containing first acid washing solution is mixed with the gallium arsenide leaching solution to recover the gallium ions, thereby ensuring that the gallium loss is <0.5%.

[0027] S3. The gallium-containing filter residue is dissolved in a strong acid solution to obtain a gallium-containing solution. Sodium sulfide is added to the gallium-containing solution to remove arsenic. After filtration, arsenic-containing filter residue and arsenic-removed filtrate are obtained. After dissolving the gallium-containing filter residue in a strong acid solution, sodium sulfide is added to it to generate arsenic sulfide precipitate, thereby removing arsenic from the gallium arsenide leaching solution and separating arsenic and gallium.

[0028] S4. Adjust the pH of the arsenic-removed filtrate to a level greater than 12 using liquid alkali, and then filter to obtain a gallium-rich filtrate. Gallium hydroxide is soluble in both strong acids and strong alkalis. When the pH of the arsenic-removed filtrate is adjusted to a level greater than 12, gallium hydroxide remains in a dissolved state, while iron ions and other metal ions form hydroxide precipitates, thus separating impurities such as iron. After filtration, a high-purity gallium-rich filtrate is obtained.

[0029] S5. Electrodeposit gallium metal onto the gallium-rich filtrate. Use a stainless steel plate as the electrode and electrodeposit metallic gallium onto the cathode at a voltage of 2-5V.

[0030] In some embodiments, the molar ratio of sodium salt to fluoride ions in gallium arsenide leaching solution in step S1 is (2~3):1; Sodium salts include at least one of sodium chloride, sodium carbonate, sodium sulfate, and sodium bicarbonate.

[0031] In some embodiments, the concentration of the sulfuric acid solution used for pickling in step S2 is 0.1~2 mol / L; The volume ratio of sulfuric acid solution to fluorine-containing filter residue is (2~3):1.

[0032] In some embodiments, the strong acid solution in step S3 includes a sulfuric acid solution; The volume ratio of the strong acid solution to the gallium-containing filter residue is (1~4):1.

[0033] In the technical solution of this application embodiment, the strong acid solution used does not include strong acid solutions containing chloride ions, so as to avoid the corrosion of the electrode plate by chloride ions during the subsequent electrodeposition process.

[0034] In some embodiments, the molar ratio of sodium sulfide to arsenic ions in the gallium-containing solution in step S3 is (2~5):1.

[0035] In some embodiments, the concentration of liquid alkali in step S4 is 100~150g / L.

[0036] In some embodiments, the electrodeposition voltage in step S5 is 2~5V.

[0037] In some embodiments, in step S3, the arsenic-containing filter residue is acid-washed to obtain a second acid washing solution, which is then mixed with a gallium-containing solution.

[0038] In the technical solution of this application embodiment, after the arsenic-containing filter residue is acid-washed, the arsenic sulfide is insoluble in sulfuric acid solution, which can dissolve the gallium ions therein and improve the gallium recovery rate.

[0039] In some embodiments, the electrolyte obtained after electrodeposition is mixed with the arsenic removal filtrate.

[0040] In the technical solution of this application embodiment, the electrolyte still contains a certain amount of unreacted gallium ions. Mixing the electrolyte with the arsenic removal filtrate and then performing electrodeposition can improve the gallium recovery rate.

[0041] In some embodiments, the gallium arsenide leaching solution includes SiO3. 2- 7~25g / L, F - 30~100g / L, Ga 2+ 10~60g / L, AsO4 3- 10~60g / L, NO3 - 120~350g / L, Fe 3+ <1g / L.

[0042] The following are some specific embodiments. It should be noted that the embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0043] I. Preparation Method Example 1 A method for extracting gallium from gallium arsenide leaching solution in a mixed system of hydrofluoric acid and nitric acid includes the following steps: S1. Add 115g of sodium chloride to 500mL of gallium arsenide leaching solution, react at room temperature for 1h to remove fluoride, and filter to obtain fluoride-containing filter residue and defluorinated filtrate.

[0044] S2. Add liquid alkali to the defluorinated filtrate, adjust the pH to 5.36, stir to react and precipitate gallium, and filter to obtain gallium-containing filter residue.

[0045] The fluorine-containing filter residue was washed with dilute sulfuric acid in a water bath at 70°C for 1 hour. After filtration, the acid-washed fluorine-containing filter residue and the first acid washing solution were obtained. The first acid washing solution was returned to be mixed with the gallium arsenide leaching solution in step S1.

[0046] S3. Add the gallium-containing filter residue to the sulfuric acid solution and stir at 70°C to completely dissolve it to obtain a gallium-containing solution. Add 105g of sodium sulfide to the gallium-containing solution and react at room temperature for 2 hours. After filtration, obtain the arsenic-containing filter residue and the arsenic-removed filtrate. S4. Adjust the pH of the arsenic-removed filtrate to 13 using liquid alkali, and then filter to obtain gallium-rich filtrate. S5. The arsenic-containing filter residue is washed with sulfuric acid solution to obtain a second acid washing solution and acid-washed arsenic-containing filter residue. The second acid washing solution is mixed with a gallium-containing solution to recover gallium. Gallium-rich filtrate was electrolyzed at 40℃. Both the anode and cathode were made of stainless steel. The electrolysis voltage was 5V and the electrolysis time was 32h. Pure gallium was obtained on the cathode plate.

[0047] Comparative Example 1 Add 15g of sodium sulfide to 300mL of gallium arsenide leaching solution, allow the precipitation reaction to proceed for 2 hours, and then filter to obtain arsenic-containing filter residue and arsenic-removed liquid.

[0048] Comparative Example 2 S1. Add 12g of sodium chloride to 150mL of gallium arsenide leaching solution, react at room temperature for 1h to remove fluoride, and obtain fluoride-containing filter residue and defluorinated filtrate after filtration.

[0049] S2. Add 30g of sodium sulfide to the defluorinated filtrate and react at room temperature for 1 hour to remove arsenic. Filter to obtain arsenic-containing filter residue and arsenic-removed liquid.

[0050] II. Testing Methods 1. Fluorine (F) - Detection method Fluorine exists in solution primarily as free fluoride ions (F⁻). - It exists in the form of fluoride or fluoride, and is measured by spectrophotometry (alizarin sulfonate colorimetric method).

[0051] Principle: Under acidic conditions, F - The reaction with the α-alizarin sulfonate complex causes the solution color to change from reddish-purple to yellow, and the F is quantified by the change in absorbance. - concentration.

[0052] 2. Detection methods for silicon (Si) Silicon in solution is mostly in the form of silicates (SiO3). 2- It exists in the form of silicic acid (H2SiO3) or colloidal silicon, and is usually measured using molybdenum blue spectrophotometry.

[0053] Principle: Under acidic conditions, silicate ions (SiO3) 2- It reacts with ammonium molybdate to form yellow silicomolybdate heteropoly acid (silicomolybdate yellow); a reducing agent (such as ascorbic acid or ferrous ammonium sulfate) is added to reduce it to blue silicomolybdate blue, and the silicon concentration is quantified by absorbance at 660 nm.

[0054] 3. Methods for detecting arsenic (As) Arsenic may exist in solution as As 3+ As 5+ Arsenic exists in the form of organic arsenic (such as methyl arsenic) and needs to be pretreated (such as acidification or reduction) to be converted into inorganic arsenic before detection. Inductively coupled plasma mass spectrometry (ICP-MS) is usually used.

[0055] Principle: Arsenic ions are ionized in plasma, separated by mass spectrometry, and their mass-to-charge ratio is detected. 75 As), quantification is achieved through ion counting.

[0056] 4. Gallium (Ga) Detection Methods Gallium is a rare dispersed metal, and it mostly exists as Ga in solution. 3+ It exists in a form, but the concentration is usually low, and it is usually detected by inductively coupled plasma mass spectrometry (ICP-MS).

[0057] Principle: Ga 3+ In plasma, it ionizes into Ga. + Its mass-to-charge ratio was detected by mass spectrometry. 69 Ga、 71 Ga), quantitative concentration.

[0058] III. Analysis of Test Results for Each Embodiment and Comparative Example The concentrations and contents (content = concentration × volume) of F, Si, As and Ga elements in the filtrate and filter residue obtained in each step of Example 1 were detected, and the removal rate and recovery rate of each element were calculated. The specific detection data are shown in Tables 1 to 7 below.

[0059] The content of each element in the gallium arsenide leaching solution and the defluorination filtrate in step S1 was detected, and the detection data are shown in Table 1 below.

[0060] Table 1. Data on sodium chloride defluorination detection

[0061] As can be seen from Table 1, adding sodium chloride (to the gallium arsenide leaching solution containing F) to the gallium arsenide leaching solution... - The defluorination process was carried out using 2.46 times the molar amount of sodium chloride, achieving a defluorination rate of over 95%. However, about 15% of the Ga was lost because the sodium fluorosilicate precipitate formed by the reaction of sodium chloride and fluorosilicate ions would carry some gallium ions with it.

[0062] The mass fraction and content of each element in the acid-washed defluorinated residue obtained after acid washing of the fluorine-containing filter residue in step S2 are shown in Table 2 below.

[0063] Table 2. Detection data of acid pickling defluorination residue

[0064] The acid-washed defluorinated residue obtained after acid washing of fluorine-containing filter residue has a Ga content of less than 0.5% and the Ga loss is controlled below 100 mg, indicating that the Ga recovery rate can be significantly improved after acid washing.

[0065] In step S2, the pH of the defluorination filtrate was adjusted to 5.36 using an alkaline solution to precipitate gallium. The filtrate was then filtered to obtain gallium-containing filter residue and a post-precipitation solution, which was used to remove nitrate. The elements in the post-precipitation solution were analyzed, and the results are shown in Table 3 below.

[0066] Table 3. Detection data of gallium-deposited liquid

[0067] As can be seen from Table 3, when the pH is adjusted to 5-6, the gallium precipitation rate reaches 99.9%, and the gallium concentration in the solution after precipitation is below 30 mg / L.

[0068] In step S3, the gallium-containing filter residue is dissolved with sulfuric acid solution to obtain a gallium-containing solution. The concentration and content of each element in the gallium-containing solution are detected, and the detection results are shown in Table 4 below.

[0069] Table 4 Monitoring data of gallium-containing solutions

[0070] As can be seen from Table 4, the solubility of gallium is 89.03%, and the solubility of arsenic is 95.03%.

[0071] In step S3, sodium sulfide (1.56 times the molar amount of arsenic) was added to the gallium-containing solution to obtain arsenic-containing filter residue and arsenic-removed filtrate. The content and concentration of each element were detected, and the detection data are shown in Table 5 below.

[0072] Table 5. Detection data of arsenic-containing filter residue and arsenic-removed filtrate

[0073] As can be seen from Table 5, after adding 1.56 times the amount of sodium sulfide to remove arsenic, the arsenic removal rate was 100%, but gallium was also lost.

[0074] In step S5, gallium is recovered after acid washing of the arsenic-containing filter residue. The recovery rate is above 96%, and the gallium content in the acid-washed arsenic-containing filter residue is controlled below 1%. The test data are shown in Table 6 below.

[0075] Table 6. Detection data of arsenic-containing filter residue from pickling

[0076] In steps S4-S5, the pH of the arsenic-removing filtrate is adjusted to 12-13 to obtain gallium-rich filtrate, which is then electrolyzed to obtain the electrolyte. The content of each element in the electrolyte is then detected, and the results are shown in Table 7 below.

[0077] Table 7. Detection data of gallium-rich filtrate and post-electrolyte

[0078] As can be seen from Table 7, a gallium hydroxide solution was obtained by adjusting the pH to 12-13 without any loss of gallium. After electrolysis of the gallium-rich filtrate, 14.6 g of pure gallium was obtained, with an electrolysis rate of 93.00%.

[0079] In Comparative Example 1, sodium sulfide (1.25 times the molar amount of arsenic) was directly added to the gallium arsenide leaching solution to obtain the arsenic-removed solution. The content of each element in the solution was then determined, as shown in Table 8 below.

[0080] Table 8 Detection data of the arsenic-removed solution from Comparative Example 1

[0081] As can be seen from Table 8, after the gallium arsenide leaching solution was directly treated with sodium sulfide to remove arsenic, the arsenic removal rate was only 12.23%, which is far lower than the 100% arsenic removal rate in Example 1, and resulted in a gallium loss of 6.4%.

[0082] In Comparative Example 2, sodium chloride was first used to remove fluoride, and then sodium sulfide, with a molar amount of arsenic, was added to remove arsenic. The contents of each element in the resulting liquid were then tested and are shown in Table 9 below.

[0083] Table 9. Detection data of the arsenic-removed solution in Comparative Example 2

[0084] As can be seen from Table 9, after adding sodium chloride, the fluoride removal rate was 97.03%, the arsenic removal rate was 13.81%, and there was no gallium loss. After adding sodium sulfide to remove arsenic, the arsenic removal rate was 71.48%, the gallium loss was 46.4%, and the nitrate removal rate was 99.79%, with a relatively large gallium loss rate.

[0085] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A method for extracting gallium from a gallium arsenide leaching solution in a mixed system of hydrofluoric acid and nitric acid, characterized in that, Includes the following steps: S1. Add sodium salt to gallium arsenide leaching solution, react and filter to obtain fluorine-containing filter residue and defluorinated filtrate; S2. The pH of the defluorination filtrate is adjusted to 5.0~5.5 using liquid alkali, and after stirring and reaction, it is filtered to obtain gallium-containing filter residue; The fluorine-containing filter residue is acid-washed to obtain a first acid washing solution, which is then mixed with the gallium arsenide leaching solution in step S1. S3. Dissolve the gallium-containing filter residue with a strong acid solution to obtain a gallium-containing solution. Add sodium sulfide to the gallium-containing solution to remove arsenic. After filtration, obtain arsenic-containing filter residue and arsenic-removed filtrate. S4. Adjust the pH of the arsenic-removing filtrate to be greater than 12 using liquid alkali, and then filter to obtain gallium-rich filtrate. S5. Electrodeposit the gallium-rich filtrate to obtain gallium metal; The gallium arsenide leaching solution includes SiO3. 2- 7~25g / L, F - 30~100g / L, Ga 2+ 10~60g / L, AsO4 3- 10~60g / L, NO3 - 120~350g / L, Fe 3+ <1g / L.

2. The method for extracting gallium from gallium arsenide leaching solution in a mixed system of hydrofluoric acid and nitric acid according to claim 1, characterized in that, The molar ratio of sodium salt to fluoride ions in gallium arsenide leaching solution in step S1 is (2~3):1; The sodium salt includes at least one of sodium chloride, sodium carbonate, sodium sulfate, and sodium bicarbonate.

3. The method for extracting gallium from gallium arsenide leaching solution in a mixed system of hydrofluoric acid and nitric acid according to claim 1, characterized in that, The concentration of the sulfuric acid solution used for pickling in step S2 is 0.1~2 mol / L; The volume ratio of the sulfuric acid solution to the fluorine-containing filter residue is (2~3):

1.

4. The method for extracting gallium from gallium arsenide leaching solution in a mixed system of hydrofluoric acid and nitric acid according to claim 1, characterized in that, The strong acid solution mentioned in step S3 includes a sulfuric acid solution; The volume ratio of the strong acid solution to the gallium-containing filter residue is (1~4):

1.

5. The method for extracting gallium from gallium arsenide leaching solution in a mixed system of hydrofluoric acid and nitric acid according to claim 1, characterized in that, The molar ratio of sodium sulfide to arsenic ions in the gallium-containing solution in step S3 is (2~5):

1.

6. The method for extracting gallium from gallium arsenide leaching solution in a mixed system of hydrofluoric acid and nitric acid according to claim 1, characterized in that, The concentration of the liquid alkali in step S4 is 100~150g / L.

7. The method for extracting gallium from gallium arsenide leaching solution in a mixed system of hydrofluoric acid and nitric acid according to claim 1, characterized in that, The electrodeposition voltage in step S5 is 2~5V.

8. The method for extracting gallium from gallium arsenide leaching solution in a mixed system of hydrofluoric acid and nitric acid according to claim 1, characterized in that, In step S3, the arsenic-containing filter residue is acid-washed to obtain a second acid washing solution, which is then mixed with the gallium-containing solution.

9. The method for extracting gallium from gallium arsenide leaching solution in a mixed system of hydrofluoric acid and nitric acid according to claim 1, characterized in that, The electrolyte obtained after electrodeposition is mixed with the arsenic removal filtrate.

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