Electrolytic separation device and electrolytic separation method for separating arsenic and gallium from gallium arsenide waste residue

Abstract

The present invention discloses an electrolytic separation device for separating arsenic and gallium from gallium arsenide waste residue, comprising an electrolytic cell, wherein an anode plate, a cathode plate, a first diaphragm and a second diaphragm are arranged in the electrolytic cell, wherein the first diaphragm and the second diaphragm are arranged between the anode plate and the cathode plate; the anode plate, the cathode plate, the first diaphragm and the second diaphragm separate the electrolytic cell into an anode region, an arsenic removal region and a cathode region which are independent of each other, wherein the anode region is located between the anode plate and the first diaphragm, the arsenic removal region is located between the first diaphragm and the second diaphragm, and the cathode region is located between the second diaphragm and the cathode plate. The present invention also provides an electrolytic separation method for separating arsenic and gallium from gallium arsenide waste residue using the electrolytic separation device. The present invention adopts a combination of slurry electrolysis and cyclone electrowinning to achieve efficient leaching of gallium arsenide waste, avoids contamination of the cathode electrolyte, and the purity of the cathode product gallium is high, thereby achieving efficient separation of gallium and arsenic.

Description

Technical Field

[0001] The invention belongs to the field of waste recycling, and in particular relates to a device and method for treating gallium arsenide waste residue. Background Art

[0002] Gallium is known as the "backbone of the electronics industry" and has a wide range of applications in the electronics field, solar cell field, metallurgy field, medical field and emerging fields. Gallium is a rare metal, mainly present in bauxite, sphalerite, chalcopyrite, germanium stone and coal mines in an isomorphous manner. In the past, the extraction of gallium mainly relied on primary minerals. However, as the contradiction between the global supply and demand of gallium metal has become increasingly intensified, the output of gallium extracted from gallium-containing waste has increased year by year. Gallium arsenide accounts for about 80% of the total gallium consumption. The global consumption of gallium metal for the production of gallium arsenide exceeds 200 tons each year. However, due to the harsh and complex production process, the yield of gallium arsenide is less than 15%, and a large amount of high-grade gallium-containing waste is generated each year, becoming the main secondary resource for recycled gallium.

[0003] At present, the recycling process of gallium arsenide waste mainly includes acid leaching, alkaline leaching, vacuum high-temperature decomposition and biological method. The above methods all have obvious defects, such as environmental pollution and equipment abrasion in the acid leaching method, high equipment requirements in the vacuum high-temperature decomposition method, and a relatively long treatment cycle in the biological method, which cannot be applied industrially. Patent CN108707927A discloses a method for recovering arsenic and gallium from waste containing gallium arsenide. The method uses waste containing gallium arsenide as an anode and electrolyzes it in an alkaline electrolyte containing gallium to obtain metallic gallium and an electrolytic residue containing arsenate. The method is simple in process, safe and environmentally friendly, and has a high metal recovery rate. However, the method has obvious defects. The presence of impurity ions such as arsenic will reduce the current efficiency of the electrolytic process, reduce the purity of the product, aggravate the side reaction of hydrogen evolution and aggravate the corrosion of the plate. In addition, the electrolyte of the method is difficult to recycle and needs to go through a large number of purification processes before it can be reused. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the above background technology, and to provide an electrolytic separation device and electrolytic separation method for separating arsenic and gallium from gallium arsenide waste slag with less catholyte pollution and less influence of impurity ions. In order to solve the above technical problems, the technical solution proposed by the present invention is:

[0005] An electrolytic separation device for separating arsenic and gallium from gallium arsenide waste residue comprises an electrolytic cell, wherein an anode plate, a cathode plate, a first diaphragm and a second diaphragm are arranged in the electrolytic cell, wherein the first diaphragm and the second diaphragm are arranged between the anode plate and the cathode plate; the anode plate, the cathode plate, the first diaphragm and the second diaphragm separate the electrolytic cell into a mutually independent anode region, an arsenic removal region and a cathode region, wherein the anode region is located between the anode plate and the first diaphragm, the arsenic removal region is located between the first diaphragm and the second diaphragm, and the cathode region is located between the second diaphragm and the cathode plate; and a power source is connected to the anode plate and the cathode plate.

[0006] The first diaphragm and the second diaphragm are anion diaphragms, which prevent solid slurry and impurity cations from entering the cathode while allowing anions to pass through.

[0007] In the above-mentioned electrolytic separation device, preferably, the anode region is connected to an anode feeding system for circulating anode slurry containing gallium arsenide waste in the anode region, the cathode region is connected to a cathode feeding system for circulating cathode electrolyte in the cathode region, and the arsenic removal region is provided with an arsenic removal agent addition port.

[0008] In the above-mentioned electrolytic separation device, preferably, the anode feeding system includes an anode liquid circulation tank, an anode liquid circulation pump, an anode liquid output pipe and an anode liquid return pipe, the anode slurry in the anode liquid circulation tank is pumped into one side of the anode area through the anode liquid circulation pump and the anode liquid output pipe, and the other side of the anode area is connected to the anode liquid circulation tank through the anode liquid return pipe to realize the circulation flow of the anode slurry.

[0009] In the above-mentioned electrolytic separation device, preferably, the cathode feeding system includes a cathode liquid circulation tank, a cathode liquid circulation pump, a cathode liquid output pipe and a cathode liquid return pipe, the cathode electrolyte in the cathode liquid circulation tank is pumped into one side of the cathode area through the cathode liquid circulation pump and the cathode liquid output pipe, and the other side of the cathode area is connected to the cathode liquid circulation tank through the cathode liquid return pipe to realize the circulation flow of the cathode electrolyte.

[0010] In the above-mentioned electrolytic separation device, preferably, the electrolytic cell is barrel-shaped, the anode plate is arranged at the center of the electrolytic cell, the cathode plate is arranged around the side wall of the electrolytic cell, and the first diaphragm and the second diaphragm are tubular diaphragms of different sizes, which are spaced between the anode plate and the cathode plate.

[0011] As a general technical concept, the present invention also provides an electrolytic separation method for separating arsenic and gallium from gallium arsenide waste slag using the above-mentioned electrolytic separation device, comprising the following steps:

[0012] (1) crushing gallium arsenide waste residue and mixing it with sodium hydroxide solution to obtain anode slurry;

[0013] (2) adding anode slurry to the anode region through the anode feeding system, adding arsenic removal agent to the arsenic removal region through the arsenic removal agent addition port, adding cathode electrolyte to the cathode region through the cathode feeding system, and circulating the anode slurry and cathode electrolyte in the anode region and cathode region respectively through the anode feeding system and the cathode feeding system; the use of a double-layer anion diaphragm (i.e., the first diaphragm and the second diaphragm) can effectively prevent impurity ions from entering the cathode, reduce electrolyte contamination, and ensure the purity of cathode gallium; and the interlayer space formed by the double-layer membrane can complete the collection of arsenic removal and arsenate precipitation;

[0014] (3) Turn on the power supply, adjust the current and voltage, and perform electrolysis. After the electrolysis is completed, collect the electrolytic product gallium in the cathode area, and collect arsenic in the arsenic removal area.

[0015] In the above electrolytic separation method, preferably, the gallium arsenide waste residue is crushed to less than 0.5 mm and fully mixed with 20-60g / L sodium hydroxide solution, and the solid-liquid ratio of the gallium arsenide waste residue to the sodium hydroxide solution is controlled to be 1: (4-8) g / mL. The above-mentioned gallium arsenide particle size control can make the gallium arsenide waste residue fully contact with the sodium hydroxide solution, improve the leaching rate, and improve the reaction efficiency; too high sodium hydroxide concentration and too low liquid-solid ratio will affect the solution viscosity, which is not conducive to the flow and filtration of the solution; too low sodium hydroxide concentration is not conducive to the leaching of gallium arsenide waste; and the concentration of sodium hydroxide will also affect the leaching of silicon and aluminum in the raw materials. When controlled at the above concentration, less impurities are leached and alkali consumption is reduced. Taking all factors into consideration, the concentration of sodium hydroxide is controlled to be 20-60g / L, and the solid-liquid ratio is 1: (4-8) g / mL.

[0016] In the electrolytic separation method, preferably, the cathode electrolyte is a sodium hydroxide solution with a concentration of 40-120 g / L, and the arsenic removal agent is a soluble calcium salt solution and / or a soluble barium salt solution. The amount of the arsenic removal agent is sufficient.

[0017] In the above electrolytic separation method, preferably, the circulation flow rate of the anode slurry and the cathode electrolyte in the anode region and the cathode region is controlled to be 200-400 L / h. When the circulation flow rate is too low, the current efficiency is low; when the circulation flow rate is too large, on the one hand, it has little effect on improving the current efficiency, and may even reduce the current efficiency; on the other hand, increasing the circulation flow rate will further increase the energy consumption of the circulation pump.

[0018] In the above electrolytic separation method, preferably, during electrolysis, the pH value of the electrolyte in the electrolytic cell is controlled to be 8.8-14, the temperature of the electrolyte in the electrolytic cell is 20-60°C, and constant current density electrolysis is adopted, and the current density is 500-1000A / m 2. Under the above conditions, arsenic enters the solution in the form of arsenate ions, passes through the first diaphragm into the arsenic removal area, forms arsenate precipitates with calcium ions or barium ions, and is deposited in this area; gallium enters the solution in the form of gallate ions, passes through two layers of diaphragms into the cathode area, and finally forms gallium liquid in the cathode area. This process can effectively achieve efficient leaching of gallium arsenide and separation of arsenic and gallium, and finally achieve selective recovery of gallium. Moreover, experiments have shown that under the above conditions, gallium and arsenic can be leached efficiently, while impurities such as aluminum and silicon are hardly leached, reducing the influence of impurity ions. In addition, as the current density increases, the cell voltage will increase accordingly. In the process of gallium electrowinning, since the reduction potential of gallium is more negative than the reduction potential of hydrogen precipitation, increasing the current density can increase the cell voltage, thereby increasing the reaction overpotential, which is conducive to the deposition of gallium. However, if the current density is too high, it will cause concentration polarization, which will reduce the current efficiency. Therefore, the current density should not be too low or too high.

[0019] In the above electrolytic separation method, preferably, the electrolytic product gallium is acid-washed, water-washed and vacuum-dried to obtain high-purity cathode gallium, and the cathode electrolyte can be reused without purification.

[0020] Compared with the prior art, the advantages of the present invention are:

[0021] 1. The electrolytic separation device for separating arsenic and gallium from gallium arsenide waste residue of the present invention adopts a special double-layer diaphragm electrolytic cell structure, which avoids the contamination of the cathode electrolyte by impurities, saves the step of cathodic electrolyte purification in the traditional process, and shortens the process flow. At the same time, an arsenic removal agent is added between the arsenic removal areas to achieve selective precipitation of arsenate ions, avoid arsenic contamination of the cathode, which is beneficial to improve the purity of arsenic in the cathode product, and reduce the effects of low current efficiency, hydrogen evolution side reaction and severe plate corrosion caused by impurity ions such as arsenic.

[0022] 2. The electrolytic separation method for separating arsenic and gallium from gallium arsenide waste slag of the present invention adopts a combination of slurry electrolysis and cyclone electrowinning to achieve efficient leaching of gallium arsenide under the action of anodic oxidation and oxidants such as oxygen. The use of cyclone electrowinning eliminates the concentration polarization phenomenon in the gallium electrolysis process and improves the current efficiency.

[0023] 3. The electrolytic separation device and method for separating arsenic and gallium from gallium arsenide waste slag of the present invention have good adaptability to raw materials and can process low-grade gallium arsenide waste slag.

[0024] 4. The electrolytic separation device and method for separating arsenic and gallium from gallium arsenide waste slag of the present invention are simple to operate, short in process, clean and pollution-free, with high recovery efficiency and easy to industrialize, thus providing a reliable technical guarantee for the efficient recovery of gallium arsenide waste slag.

[0025] In general, the present invention adopts a combination of slurry electrolysis and cyclone electrowinning to achieve efficient leaching of gallium arsenide waste, and adopts a double-layer diaphragm electrolytic cell to prevent solid slurry and impurities from diffusing to the cathode, and the double-layer diaphragm constructs a special arsenic removal area, and adopts an arsenic removal agent to precipitate arsenic, thereby avoiding the pollution of the cathode electrolyte. The purification workload of the cathode electrolyte is small, and it can be reused, and the purity of the cathode product gallium is high. Gallium is electrolyzed and collected at the cathode to obtain a high-purity gallium product, and arsenic products can be obtained by collecting in the arsenic removal area, thereby achieving efficient separation of gallium and arsenic. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 It is a schematic structural diagram of the electrolytic separation device for separating arsenic and gallium in gallium arsenide waste slag according to the present invention.

[0028] Figure 2 This is the SEM spectrum of the gallium arsenide waste slag raw material used in Example 1 ((a) and (b) represent different magnifications, respectively; the main component of point A in (b) is aluminum oxide, point B represents gallium arsenide, and the main component of point C is silicon and zirconium oxides).

[0029] Figure 3 This is the EDS test result of the gallium arsenide waste slag raw material used in Example 1.

[0030] Figure 4 This is the XRD phase analysis result of the gallium arsenide waste slag raw material used in Example 1.

[0031] Figure 5 The SEM images of the leached residue obtained in Example 1 ((a) and (b) represent different magnifications, respectively).

[0032] Legend:

[0033] 1. Electrolytic cell; 2. Anode plate; 3. Cathode plate; 4. First diaphragm; 5. Second diaphragm; 6. Anode area; 7. Arsenic removal area; 8. Cathode area; 9. Anode liquid circulation tank; 10. Anode liquid circulation pump; 11. Anode liquid output pipe; 12. Anode liquid return pipe; 13. Cathode liquid circulation tank; 14. Cathode liquid circulation pump; 15. Cathode liquid output pipe; 16. Cathode liquid return pipe. DETAILED DESCRIPTION

[0034] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with the accompanying drawings and preferred embodiments of the present invention, but the protection scope of the present invention is not limited to the following specific embodiments.

[0035] Unless otherwise defined, all the professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0036] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0037] The XRF analysis results and ICP analysis results of the gallium arsenide waste slag used in the following examples are shown in Table 1 and Table 2 respectively.

[0038] Table 1: XRF analysis results of GaAs waste

[0039]

[0040] Table 2: ICP analysis results of GaAs waste

[0041]

[0042] Figure 2 This is the SEM spectrum of gallium arsenide waste slag raw material. Figure 3 This is the EDS test result of gallium arsenide waste slag raw material. Figure 4 This is the XRD phase analysis result of gallium arsenide waste slag raw material. Figure 2-Figure 4 It can be seen that there are mainly three phases in gallium arsenide waste, which intuitively reflects that the distribution areas of gallium and arsenic elements almost overlap, the distribution areas of zirconium and silicon elements overlap, and the aluminum element is distributed alone, that is, gallium arsenide is distributed independently from aluminum oxide and zirconium silicate, and there is no interweaving and embedding phenomenon between the three phases.

[0043] Embodiment 1:

[0044] like Figure 1 As shown, the electrolytic separation device for separating arsenic and gallium in gallium arsenide waste slag of this embodiment includes an electrolytic cell 1, in which an anode plate 2, a cathode plate 3, a first diaphragm 4 and a second diaphragm 5 are arranged, and the first diaphragm 4 and the second diaphragm 5 are spaced between the anode plate 2 and the cathode plate 3; the anode plate 2, the cathode plate 3, the first diaphragm 4 and the second diaphragm 5 separate the electrolytic cell 1 into a mutually independent anode region 6, an arsenic removal region 7 and a cathode region 8, the anode region 6 is located between the anode plate 2 and the first diaphragm 4, the arsenic removal region 7 is located between the first diaphragm 4 and the second diaphragm 5, and the cathode region 8 is located between the second diaphragm 5 and the cathode plate 3; the anode plate 2 and the cathode plate 3 are connected to a power source.

[0045] Specifically, in this embodiment, the electrolytic cell 1 is barrel-shaped, the anode plate 2 is arranged at the center of the electrolytic cell 1, the cathode plate 3 is arranged around the side wall of the electrolytic cell 1, and the first diaphragm 4 and the second diaphragm 5 are tubular diaphragms of different sizes, which are spaced between the anode plate 2 and the cathode plate 3.

[0046] In this embodiment, the anode region 6 is connected to an anode feeding system for circulating the anode slurry containing gallium arsenide waste in the anode region 6, the cathode region 8 is connected to a cathode feeding system for circulating the cathode electrolyte in the cathode region 8, and the arsenic removal region 7 is provided with an arsenic removal agent addition port.

[0047] In this embodiment, the anode feeding system includes an anode liquid circulation tank 9, an anode liquid circulation pump 10, an anode liquid output pipe 11 and an anode liquid return pipe 12. The anode slurry in the anode liquid circulation tank 9 is pumped into one side of the anode area 6 through the anode liquid circulation pump 10 and the anode liquid output pipe 11, and the other side of the anode area 6 is connected to the anode liquid circulation tank 9 through the anode liquid return pipe 12 to realize the circulation flow of the anode slurry.

[0048] In this embodiment, the cathode feeding system includes a cathode liquid circulation tank 13, a cathode liquid circulation pump 14, a cathode liquid output pipe 15 and a cathode liquid return pipe 16. The cathode electrolyte in the cathode liquid circulation tank 13 is pumped into one side of the cathode area 8 through the cathode liquid circulation pump 14 and the cathode liquid output pipe 15, and the other side of the cathode area 8 is connected to the cathode liquid circulation tank 13 through the cathode liquid return pipe 16 to realize the circulation flow of the cathode electrolyte.

[0049] An electrolytic separation method for separating arsenic and gallium from gallium arsenide waste slag using the electrolytic separation device comprises the following steps:

[0050] (1) After drying, crushing, grinding and screening the gallium arsenide waste residue, a material with a particle size of less than 0.5 mm was obtained; the ground gallium arsenide waste residue was gray-black, and after mixing evenly, XRF detection and ICP detection were performed, and the results were shown in Table 1 and Table 2 above, respectively. It can be seen from the table that the contents of gallium and arsenic in the raw material were 3.03% and 3.39% respectively, and the main impurities were aluminum, zirconium, silicon, etc. 100g of the gallium arsenide powder obtained after grinding was fully mixed with 20g / L sodium hydroxide solution at a liquid-to-solid ratio of 1:4g / mL to obtain an anode slurry.

[0051] (2) The anode slurry obtained in step (1) is injected into the anode region 6, a sufficient amount of a mixture of calcium chloride and barium chloride is introduced into the arsenic removal region 7, and a certain volume of 40 g / L sodium hydroxide solution is introduced into the cathode region 8, and the pH value in the electrolytic cell 1 is adjusted to 10; the electrolytic cell 1 is connected to the cathode liquid circulation tank and the cathode liquid circulation pump (for specific connection methods, see Figure 1); control the temperature in the electrolytic cell 1 to 30°C, turn on the cathode and anode liquid circulation pumps to circulate the anode slurry and cathode electrolyte, and control the circulation flow rate to 200L / h.

[0052] (3) After the anode slurry and cathode electrolyte in step (2) are stably circulated, turn on the power supply and charge the electrolyte at a current density of 500 A / m 2 The gallium electrolysis starts at the following time. After the electrolysis reaction is finished, the power supply and the cathode liquid circulation pumps are turned off, and the cathode electrolysis product gallium is collected; arsenic is deposited in the arsenic removal area 7 under the action of the arsenic removal agent.

[0053] (4) The gallium product obtained in step (3) is washed with 0.5 mol / L hydrochloric acid and pure water at 50° C. for multiple times with stirring, and then vacuum dried to obtain cathode gallium.

[0054] The SEM spectrum of the leached slag obtained after electrolysis in this embodiment is as follows: Figure 5 As shown by Figure 4 It can be seen that the white particles representing gallium arsenide in the leached slag have basically disappeared, while the morphology of the other two particles has basically not changed, indicating that the leaching effect of gallium arsenide is better during the leaching process, and the leaching rate of other impurities is lower.

[0055] According to calculation, 2.721g of gallium was finally collected in this embodiment, the recovery rate was 89.8%, the current efficiency was above 41%, and the purity of cathode gallium was 99.991% after testing. In addition, the cathode electrolyte in this embodiment has less impurities, fewer purification steps, and is easy to recycle.

[0056] Embodiment 2:

[0057] An electrolytic separation method for separating arsenic and gallium from gallium arsenide waste slag using the electrolytic separation device in the above-mentioned embodiment 1 comprises the following steps:

[0058] (1) After drying, crushing, grinding and screening the gallium arsenide waste residue, a material with a particle size of less than 0.5 mm was obtained; the ground gallium arsenide waste residue was gray-black, and after mixing evenly, XRF detection and ICP detection were performed, and the results were shown in Table 1 and Table 2, respectively. It can be seen from the table that the contents of gallium and arsenic in the raw material were 3.03% and 3.39%, respectively, and the main impurities were aluminum, zirconium, silicon, etc. 100g of the gallium arsenide powder obtained after grinding was fully mixed with 30g / L sodium hydroxide solution at a liquid-solid ratio of 1:4g / mL to obtain an anode slurry.

[0059] (2) The anode slurry obtained in step (1) is injected into the anode region 6, a sufficient amount of a mixture of calcium chloride and barium chloride is introduced into the arsenic removal region 7, and a certain volume of 100 g / L sodium hydroxide solution is introduced into the cathode region 8, and the pH value in the electrolytic cell 1 is adjusted to 12; the electrolytic cell 1 is connected to the cathode liquid circulation tank and the cathode liquid circulation pump (for specific connection methods, see Figure 1 ); control the temperature in the electrolytic cell 1 to 40°C, turn on the cathode and cathode liquid circulation pumps to circulate the anode slurry and cathode electrolyte, and control the circulation flow rate to 200L / h.

[0060] (3) After the anode slurry and cathode electrolyte in step (2) are stably circulated, turn on the power supply and charge the electrolyte at a current density of 500 A / m 2 The gallium electrolysis starts at the following time. After the electrolysis reaction is finished, the power supply and the cathode liquid circulation pumps are turned off, and the cathode electrolysis product gallium is collected; arsenic is deposited in the arsenic removal area 7 under the action of the arsenic removal agent.

[0061] (4) The gallium product obtained in step (3) is washed with 0.5 mol / L hydrochloric acid and pure water at 50° C. for multiple times with stirring, and then vacuum dried to obtain cathode gallium.

[0062] According to calculation, 2.834 g of gallium was finally collected in this embodiment, the recovery rate was 93.5%, the current efficiency was 43.4%, and the purity of cathode gallium was 99.991%. In addition, the cathode electrolyte in this embodiment has less impurities, fewer purification steps, and is easy to recycle.

[0063] Embodiment 3:

[0064] An electrolytic separation method for separating arsenic and gallium from gallium arsenide waste slag using the electrolytic separation device in the above-mentioned embodiment 1 comprises the following steps:

[0065] (1) After drying, crushing, grinding and screening the gallium arsenide waste residue, a material with a particle size of less than 0.5 mm was obtained; the ground gallium arsenide waste residue was gray-black, and after mixing evenly, XRF detection and ICP detection were performed, and the results were shown in Table 1 and Table 2, respectively. It can be seen from the table that the contents of gallium and arsenic in the raw material were 3.03% and 3.39%, respectively, and the main impurities were aluminum, zirconium, silicon, etc. 100g of the gallium arsenide powder obtained after grinding was fully mixed with 30g / L sodium hydroxide solution at a liquid-solid ratio of 1:5g / mL to obtain an anode slurry.

[0066] (2) The anode slurry obtained in step (1) is injected into the anode region 6, a sufficient amount of a mixture of calcium chloride and barium chloride is introduced into the arsenic removal region 7, and a certain volume of 80 g / L sodium hydroxide solution is introduced into the cathode region 8, and the pH value in the electrolytic cell 1 is adjusted to 12; the electrolytic cell 1 is connected to the cathode liquid circulation tank and the cathode liquid circulation pump (for specific connection methods, see Figure 1 ); control the temperature in the electrolytic cell 1 to 50°C, turn on the cathode and anode liquid circulation pumps to circulate the anode slurry and cathode electrolyte, and control the circulation flow rate to 200L / h.

[0067] (3) After the anode slurry and cathode electrolyte in step (2) are stably circulated, turn on the power supply and charge the electrolyte at a current density of 700 A / m2 The gallium electrolysis starts at the following time. After the electrolysis reaction is finished, the power supply and the cathode liquid circulation pumps are turned off, and the cathode electrolysis product gallium is collected; arsenic is deposited in the arsenic removal area 7 under the action of the arsenic removal agent.

[0068] (4) The gallium product obtained in step (3) is washed with 0.5 mol / L hydrochloric acid and pure water at 50° C. for multiple times with stirring, and then vacuum dried to obtain cathode gallium.

[0069] According to calculation, 2.892 g of gallium was finally collected in this embodiment, the recovery rate was 95.4%, the current efficiency was 45.7%, and the purity of gallium was 99.993% after testing. In addition, the cathode electrolyte in this embodiment has less impurities, fewer purification steps, and is easy to recycle.

[0070] Embodiment 4:

[0071] An electrolytic separation method for separating arsenic and gallium from gallium arsenide waste slag using the electrolytic separation device in the above-mentioned embodiment 1 comprises the following steps:

[0072] (1) After drying, crushing, grinding and screening the gallium arsenide waste residue, a material with a particle size of less than 0.5 mm was obtained; the ground gallium arsenide waste residue was gray-black, and after mixing evenly, XRF detection and ICP detection were performed, and the results were shown in Table 1 and Table 2, respectively. It can be seen from the table that the contents of gallium and arsenic in the raw material were 3.03% and 3.39%, respectively, and the main impurities were aluminum, zirconium, silicon, etc. 100g of the gallium arsenide powder obtained after grinding was fully mixed with 60g / L sodium hydroxide solution at a liquid-to-solid ratio of 1:8g / mL to obtain an anode slurry.

[0073] (2) The anode slurry obtained in step (1) is injected into the anode region 6, a sufficient amount of a mixture of calcium chloride and barium chloride is introduced into the arsenic removal region 7, and a certain volume of 120 g / L sodium hydroxide solution is introduced into the cathode region 8, and the pH value in the electrolytic cell 1 is adjusted to 14; the electrolytic cell 1 is connected to the cathode liquid circulation tank and the cathode liquid circulation pump (for specific connection methods, see Figure 1 ); control the temperature in the electrolytic cell 1 to 60°C, turn on the cathode and anode liquid circulation pumps to circulate the anode slurry and cathode electrolyte, and control the circulation flow rate to 400L / h.

[0074] (3) After the anode slurry and cathode electrolyte in step (2) are stably circulated, turn on the power supply and charge the electrolyte at a current density of 800 A / m 2 The gallium electrolysis starts at the following time. After the electrolysis reaction is finished, the power supply and the cathode liquid circulation pumps are turned off, and the cathode electrolysis product gallium is collected; arsenic is deposited in the arsenic removal area 7 under the action of the arsenic removal agent.

[0075] (4) The gallium product obtained in step (3) is washed with 0.5 mol / L hydrochloric acid and pure water at 50° C. for multiple times with stirring, and then vacuum dried to obtain cathode gallium.

[0076] According to calculation, 2.913 g of gallium was finally collected in this embodiment, the recovery rate was 96.1%, the current efficiency was 46.1%, and the purity of gallium was 99.992% after testing. In addition, the cathode electrolyte in this embodiment has less impurities, fewer purification steps, and is easy to recycle.

[0077] Embodiment 5:

[0078] An electrolytic separation method for separating arsenic and gallium from gallium arsenide waste slag using the electrolytic separation device in the above-mentioned embodiment 1 comprises the following steps:

[0079] (1) After drying, crushing, grinding and screening the gallium arsenide waste residue, a material with a particle size of less than 0.5 mm was obtained; the ground gallium arsenide waste residue was gray-black, and after mixing evenly, XRF detection and ICP detection were performed, and the results were shown in Table 1 and Table 2, respectively. It can be seen from the table that the contents of gallium and arsenic in the raw material were 3.03% and 3.39%, respectively, and the main impurities were aluminum, zirconium, silicon, etc. 100g of the gallium arsenide powder obtained after grinding was fully mixed with 20g / L sodium hydroxide solution at a liquid-to-solid ratio of 1:4g / mL to obtain an anode slurry.

[0080] (2) The anode slurry obtained in step (1) is injected into the anode region 6, a sufficient amount of a mixture of calcium chloride and barium chloride is introduced into the arsenic removal region 7, and a certain volume of 120 g / L sodium hydroxide solution is introduced into the cathode region 8, and the pH value in the electrolytic cell 1 is adjusted to 14; the electrolytic cell 1 is connected to the cathode liquid circulation tank and the cathode liquid circulation pump (for specific connection methods, see Figure 1 ); control the temperature in the electrolytic cell 1 to 50°C, turn on the cathode and anode liquid circulation pumps to circulate the anode slurry and cathode electrolyte, and control the circulation flow rate to 400L / h.

[0081] (3) After the anode slurry and cathode electrolyte in step (2) are stably circulated, turn on the power supply and charge the electrolyte at a current density of 1000 A / m 2 The gallium electrolysis starts at the following time. After the electrolysis reaction is finished, the power supply and the cathode liquid circulation pumps are turned off, and the cathode electrolysis product gallium is collected; arsenic is deposited in the arsenic removal area 7 under the action of the arsenic removal agent.

[0082] (4) The gallium product obtained in step (3) is washed with 0.5 mol / L hydrochloric acid and pure water at 50° C. for multiple times with stirring, and then vacuum dried to obtain cathode gallium.

[0083] According to calculation, 2.935g of gallium was finally collected in this embodiment, the recovery rate was 96.9%, the current efficiency was 46.8%, and the purity of gallium was 99.995% after testing. In addition, the cathode electrolyte in this embodiment has less impurities, fewer purification steps, and is easy to recycle.

[0084] Embodiment 6:

[0085] An electrolytic separation method for separating arsenic and gallium from gallium arsenide waste slag using the electrolytic separation device in the above-mentioned embodiment 1 comprises the following steps:

[0086] (1) After drying, crushing, grinding and screening the gallium arsenide waste residue, a material with a particle size of less than 0.5 mm was obtained; the ground gallium arsenide waste residue was gray-black, and after mixing evenly, XRF detection and ICP detection were performed, and the results were shown in Table 1 and Table 2, respectively. It can be seen from the table that the contents of gallium and arsenic in the raw material were 3.03% and 3.39%, respectively, and the main impurities were aluminum, zirconium, silicon, etc. 100g of the gallium arsenide powder obtained after grinding was fully mixed with 20g / L sodium hydroxide solution at a liquid-to-solid ratio of 1:8g / mL to obtain an anode slurry.

[0087] (2) The anode slurry obtained in step (1) is injected into the anode region 6, a sufficient amount of a mixture of calcium chloride and barium chloride is introduced into the arsenic removal region 7, and a certain volume of 60 g / L sodium hydroxide solution is introduced into the cathode region 8, and the pH value in the electrolytic cell 1 is adjusted to 8.8; the electrolytic cell 1 is connected to the cathode liquid circulation tank and the cathode liquid circulation pump (for specific connection methods, see Figure 1 ); control the temperature in the electrolytic cell 1 to 30°C, turn on the cathode and anode liquid circulation pumps to circulate the anode slurry and cathode electrolyte, and control the circulation flow rate to 200L / h.

[0088] (3) After the anode slurry and cathode electrolyte in step (2) are stably circulated, turn on the power supply and charge the electrolyte at a current density of 500 A / m 2 The gallium electrolysis starts at the following time. After the electrolysis reaction is finished, the power supply and the cathode liquid circulation pumps are turned off, and the cathode electrolysis product gallium is collected; arsenic is deposited in the arsenic removal area 7 under the action of the arsenic removal agent.

[0089] (4) The gallium product obtained in step (3) is washed with 0.5 mol / L hydrochloric acid and pure water at 50° C. for multiple times with stirring, and then vacuum dried to obtain cathode gallium.

[0090] According to calculation, 2.456 g of gallium was finally collected in this embodiment, the recovery rate was 81.1%, the current efficiency was 35.7%, and the purity of gallium was 99.991% after testing. In addition, the cathode electrolyte in this embodiment has less impurities, fewer purification steps, and is easy to recycle.

[0091] Comparative Example 1:

[0092] Compared with the electrolytic separation device in Example 1, the electrolytic separation device in this comparative example is only provided with the first diaphragm 4, without the second diaphragm 5, and only has the anode region 6 and the cathode region 8, without the arsenic removal region 7, and is otherwise the same as the electrolytic separation device in Example 1.

[0093] An electrolytic separation method for separating arsenic and gallium from gallium arsenide waste residue comprises the following steps:

[0094] (1) After drying, crushing, grinding and screening the gallium arsenide waste residue, a material with a particle size of less than 0.5 mm was obtained; the ground gallium arsenide waste residue was gray-black, and after mixing evenly, XRF detection and ICP detection were performed, and the results were shown in Table 1 and Table 2, respectively. It can be seen from the table that the contents of gallium and arsenic in the raw material were 3.03% and 3.39%, respectively, and the main impurities were aluminum, zirconium, silicon, etc. 100g of the gallium arsenide powder obtained after grinding was fully mixed with 30g / L sodium hydroxide solution at a liquid-solid ratio of 1:5g / mL to obtain an anode slurry.

[0095] (2) The anode slurry obtained in step (1) is injected into the anode region 6, a single-layer diaphragm is used in the electrolytic cell 1, no arsenic removal region 7 is provided, and no arsenic removal agent is added; a certain volume of 80 g / L sodium hydroxide solution is introduced into the cathode region 8, and the pH value in the electrolytic cell 1 is adjusted to 12; the electrolytic cell 1 is connected to the cathode liquid circulation tank and the cathode liquid circulation pump (for specific connection methods, see Figure 1 ); control the temperature in the electrolytic cell 1 to 50°C, turn on the cathode and anode liquid circulation pumps to circulate the anode slurry and cathode electrolyte, and control the circulation flow rate to 200L / h.

[0096] (3) After the anode slurry and cathode electrolyte in step (2) are stably circulated, turn on the power supply and charge the electrolyte at a current density of 700 A / m 2 The gallium electrolysis was started at the following time. After the electrolysis reaction was finished, the power supply and the cathode liquid circulation pumps were turned off, and the cathode electrolysis product gallium was collected.

[0097] (4) The gallium product obtained in step (3) is washed with 0.5 mol / L hydrochloric acid and pure water at 50° C. for multiple times with stirring, and then vacuum dried to obtain cathode gallium.

[0098] According to calculation, 2.878 g of gallium was finally collected in this comparative example, the recovery rate was 94.98%, the current efficiency was 43.2%, and the purity of gallium was 99.88% after testing. The impurity content in the cathode electrolyte in this comparative example was relatively high.

Claims

1. An electrolytic separation method for separating arsenic and gallium from gallium arsenide waste residue, characterized in that: The following electrolytic separation device is used, comprising an electrolytic cell (1), wherein the electrolytic cell (1) is provided with an anode plate (2), a cathode plate (3), a first diaphragm (4) and a second diaphragm (5), wherein the first diaphragm (4) and the second diaphragm (5) are arranged between the anode plate (2) and the cathode plate (3); the anode plate (2), the cathode plate (3), the first diaphragm (4) and the second diaphragm (5) separate the electrolytic cell (1) into an anode region (6), an arsenic removal region (7) and a cathode region (8) which are independent of each other, wherein the anode region (6) is located between the anode plate (2) and the first diaphragm (4), the arsenic removal region (7) is located between the first diaphragm (4) and the second diaphragm (5), and the cathode region (8) is located between the second diaphragm (5) and the cathode plate (3); the first diaphragm (4) and the second diaphragm (5) are both anion diaphragms; and a power source is connected to the anode plate (2) and the cathode plate (3); The anode region (6) is connected to an anode feeding system for circulating anode slurry containing gallium arsenide waste in the anode region (6); the cathode region (8) is connected to a cathode feeding system for circulating cathode electrolyte in the cathode region (8); and the arsenic removal region (7) is provided with an arsenic removal agent addition port; The electrolytic separation method comprises the following steps: (1) crushing gallium arsenide waste residue and fully mixing it with sodium hydroxide solution to obtain anode slurry; (2) adding anode slurry to the anode region (6) through the anode feeding system, adding arsenic removal agent to the arsenic removal region (7) through the arsenic removal agent feeding port, adding cathode electrolyte to the cathode region (8) through the cathode feeding system, and circulating the anode slurry and cathode electrolyte in the anode region (6) and cathode region (8) respectively through the anode feeding system and the cathode feeding system; (3) Turn on the power supply to start electrolysis. After the electrolysis is completed, collect the electrolytic product gallium in the cathode area (8), and collect arsenic in the arsenic removal area (7).

2. The electrolytic separation method according to claim 1, characterized in that: The anode feeding system comprises an anode liquid circulation tank (9), an anode liquid circulation pump (10), an anode liquid output pipe (11) and an anode liquid return pipe (12); the anode slurry in the anode liquid circulation tank (9) is pumped into one side of the anode region (6) through the anode liquid circulation pump (10) and the anode liquid output pipe (11); the other side of the anode region (6) is connected to the anode liquid circulation tank (9) through the anode liquid return pipe (12) to achieve a circulating flow of the anode slurry.

3. The electrolytic separation method according to claim 1, characterized in that: The cathode feeding system comprises a cathode liquid circulation tank (13), a cathode liquid circulation pump (14), a cathode liquid output pipe (15) and a cathode liquid return pipe (16); the cathode electrolyte in the cathode liquid circulation tank (13) is pumped into one side of the cathode region (8) through the cathode liquid circulation pump (14) and the cathode liquid output pipe (15); the other side of the cathode region (8) is connected to the cathode liquid circulation tank (13) through the cathode liquid return pipe (16) to achieve a circulating flow of the cathode electrolyte.

4. The electrolytic separation method according to claim 1, characterized in that: The electrolytic cell (1) is in the shape of a cylinder. The anode plate (2) is arranged at the center of the electrolytic cell (1). The cathode plate (3) is arranged around the side wall of the electrolytic cell (1). The first diaphragm (4) and the second diaphragm (5) are circular tubular diaphragms of different sizes and are arranged between the anode plate (2) and the cathode plate (3).

5. The electrolytic separation method according to claim 1, characterized in that: The gallium arsenide waste residue is crushed to less than 0.5 mm and fully mixed with 20-60 g / L sodium hydroxide solution, and the solid-liquid ratio of the gallium arsenide waste residue to the sodium hydroxide solution is controlled to be 1: (4-8) g / mL.

6. The electrolytic separation method according to claim 1, characterized in that: The cathode electrolyte is a sodium hydroxide solution with a concentration of 40-120 g / L, and the arsenic removal agent is a soluble calcium salt solution and / or a soluble barium salt solution.

7. The electrolytic separation method according to any one of claims 1, 5 and 6, characterized in that: The circulation flow rate of the anode slurry and the cathode electrolyte in the anode region (6) and the cathode region (8) during circulation is controlled to be 200-400 L / h.

8. The electrolytic separation method according to any one of claims 1, 5 and 6, characterized in that: During electrolysis, the pH value of the electrolyte in the electrolytic cell (1) is controlled to be between 8.8 and 14, the temperature of the electrolyte in the electrolytic cell (1) is between 20 and 60° C., and constant current density electrolysis is adopted, and the current density is between 500 and 1000 A / m 2 .

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