Application of single crystal gallium electrode in electrolytic refining and preparation method of single crystal gallium electrode

Abstract

The invention discloses application of a single crystal gallium electrode in electrolytic refining and a preparation method, and belongs to the technical field of production of scattered metal gallium. The method comprises the following steps: melting and cooling metal gallium, grafting a seed crystal with a specific crystal form into obtained liquid gallium, carrying out cooling crystallization, pickling, and cutting to obtain a single crystal gallium electrode with a target crystal form and specification. A single crystal gallium electrode in a specific crystal form is subjected to acid pickling and then serves as a cathode, crude gallium serves as an anode, the cathode and the anode are placed in an electrolyte, electrolysis is conducted within the set temperature range, and refined gallium is obtained. By adopting the scheme provided by the invention, the problems that corrosion or hydrogen evolution and other side reactions are preferentially generated by utilizing the polycrystalline gallium electrode, and optimal electrochemical selective impurity pollution cannot be realized due to limitation of grain boundary defects and crystal face mixing are solved at the same time; and the problems of low current efficiency, impurity pollution, high energy consumption and unstable process caused by a common cathode material are solved.

Description

Technical Field

[0001] This invention belongs to the field of rare dispersed metal gallium production technology, and relates to the application and preparation method of a single crystal gallium electrode in electrolytic refining. It is applicable to the electrolytic refining method to further purify industrial gallium or crude gallium, and specifically relates to a preparation method of an electrolytically refined gallium single crystal electrode. Background Technology

[0002] Gallium is a core material for producing semiconductors such as GaAs (gallium arsenide), GaP (gallium phosphide), GaSb (gallium antimonide), and GaN (gallium nitride). With the rapid development of the semiconductor industry, the demand for high-purity gallium (6N, 7N) is increasingly urgent. Gallium has a melting point of 29.78℃ and exhibits thermal expansion and contraction upon solidification. It also has a high degree of supercooling, requiring very low temperatures to solidify. High-purity gallium is produced through a combination of one or more methods, including chemical extraction, electrolytic refining, vacuum distillation, and crystallization. Electrolytic refining is one of the important industrial methods for preparing high-purity gallium. This method uses crude gallium as the anode and high-purity gallium as the cathode, with sodium hydroxide (NaOH) solution as the electrolyte for electrochemical deposition.

[0003] However, in existing industrial practices of gallium electrolysis, traditional cathode materials (especially stainless steel and platinum) exhibit strong catalytic activity towards the hydrogen evolution reaction in the electrolyte, resulting in a very low hydrogen evolution overpotential. This leads to severe hydrogen evolution side reactions during electrolysis, a significant decrease in current efficiency, and accelerated electrolyte evaporation. Furthermore, during electrolysis, electrode materials containing non-target products are corroded by gallium. For example, when using non-gallium metals as cathodes, these materials are prone to corrosion in strongly alkaline electrolytes and in contact with low-melting-point gallium, leading to the introduction of impurities. Therefore, liquid gallium electrodes are often used for electrolysis. However, liquid gallium is extremely chemically reactive, instantly forming a dense insulating oxide layer (Ga2O3) in the electrolyte (aqueous solution). This oxide layer passivates the electrode surface, severely hindering electron transfer and gallium deposition. Moreover, as a fluid, the liquid electrode lacks a fixed geometry and surface area, resulting in extremely uneven current density distribution within the electrolytic cell, making stable and uniform electrodeposition difficult and hindering industrial control. The scheme described in Chinese patent CN101413135A, which operates electrolysis at 50°C, not only increases heating energy consumption but also requires a complex external cooling device to maintain the solid state of the electrode leads, increasing equipment cost and system complexity. Given these drawbacks of liquid gallium, using "solid-state gallium" electrodes at temperatures below its melting point (i.e., <29.78°C) is a more ideal choice.

[0004] Solid-state electrodes possess stable geometry, are easy to manipulate, and effectively mitigate the disordered regeneration of the oxide layer "skin." However, conventionally prepared solid-state gallium electrodes are polycrystalline, containing numerous grain boundaries. Grain boundaries are high-energy regions with disordered atomic arrangement, acting as highly active sites in electrochemical reactions. They are prone to preferential corrosion or side reactions such as hydrogen evolution, and are also areas of impurity accumulation. Furthermore, conventional solid-state polycrystalline gallium electrodes are limited by grain boundary defects and mixed crystal planes, failing to achieve optimal electrochemical selectivity. Therefore, developing high-efficiency cathode materials that inhibit gallium evolution and suppress hydrogen evolution is crucial. Patent CN102011142A proposes a gallium electrolytic refining method using gallium sheets and protective platinum wire leads to fabricate electrodes, but does not disclose the electrode fabrication method. Under this patent, the platinum wire is also easily corroded by gallium and the electrolyte, generating impurities, and the use of precious metals increases production costs. Summary of the Invention

[0005] To address the shortcomings of the existing technologies, this invention provides a simple, mass-producible method for the application and fabrication of single-crystal gallium electrodes, which avoids the use of precious metals, simplifies the equipment, and reduces production costs.

[0006] The first aspect of this invention provides an application of a single-crystal gallium electrode in electrolytic refining, wherein the crystal orientation of the single-crystal gallium electrode is one of (111), (102), (200), (113), and (211), and the application process is as follows:

[0007] The single-crystal gallium electrode is acid-washed and used as the cathode, while crude gallium is used as the anode. The cathode and anode are placed in an electrolyte and electrolyzed within a set temperature range to obtain refined gallium.

[0008] The pickling process involves washing with a 5% HCl solution for 1 minute.

[0009] The electrolyte contains 2.0 mol / L to 6.0 mol / L NaOH and 20 g / L to 80 g / L sodium gallate;

[0010] During electrolysis, the electrolysis temperature is 5℃~28℃, and the current density is 100A / m. 2 ~1000A / m 2 ;

[0011] During electrolysis, the electrode distance is 20mm~60mm.

[0012] A second aspect of the present invention provides a method for fabricating the single-crystal gallium electrode, comprising the following steps:

[0013] Step 1. After melting metallic gallium, transfer it to a plastic tray, place the plastic tray in a low-temperature incubator to cool it, and obtain liquid gallium;

[0014] Step 2. Graft the seed crystal of the target crystal orientation into liquid gallium, remove the surface gallium oxide film with a scraper, and then cool and crystallize until the liquid gallium is completely crystallized along the seed crystal;

[0015] Step 3. Turn off the low-temperature incubator, remove the tray and demold to obtain the electrode blank;

[0016] Step 4. Wash the electrode blank with dilute acid to remove the gallium oxide film on the surface;

[0017] Step 5. Cut the acid-washed electrode blank according to the target electrode size to obtain the single-crystal gallium electrode.

[0018] In step 1, the purity of the metallic gallium electrode is not lower than the purity of gallium in the target gallium electrode;

[0019] The plastic pallet is specifically made of one of the commercially available materials: polytetrafluoroethylene, polypropylene, or polyethylene.

[0020] Low-temperature incubators are low-temperature blower incubators, refrigerators, or other equipment that can achieve an incubation temperature not exceeding 0°C;

[0021] In step 2, the crystal orientation of the seed crystal is one of (111), (102), (200), (113), (211); the crystal orientation of the crystal gallium formed by the liquid gallium crystallizing outward along the seed gallium is the same as that of the seed crystal.

[0022] The cooling crystallization temperature is 0℃~29℃;

[0023] In step 4, the dilute acid is one of the pure aqueous solutions of hydrochloric acid, nitric acid, or sulfuric acid, with a concentration of 0.1 mol / L to 5 mol / L.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] This invention proposes an application and preparation method of a single-crystal gallium electrode in electrolytic refining. Utilizing the specific crystal plane advantages of single-crystal gallium, it achieves the refining of GaO2... - The low potential of the / Ga (gallium deposition) reaction and the high potential for the hydrogen evolution reaction (i.e., high hydrogen evolution overpotential) simultaneously solve the problems of preferential corrosion or hydrogen evolution side reactions generated by polycrystalline gallium electrodes, the limitations of grain boundary defects and crystal plane mixing leading to the inability to achieve optimal electrochemical selectivity due to impurity contamination, and the problems of low current efficiency, impurity contamination, high energy consumption, and process instability caused by ordinary cathode materials. The single-crystal electrode prepared by the method provided by this invention eliminates the grain boundary defects of polycrystalline materials and can expose uniform crystal planes with specific preferential characteristics. Furthermore, the solidification of high-purity metallic gallium requires a large degree of undercooling, and seed crystal induction can effectively reduce the nucleation barrier, ensuring the orderly growth of electrode crystals and reducing the generation of impurity crystals. Attached Figure Description

[0026] Figure 1 The XRD patterns of single-crystal gallium electrodes prepared according to different embodiments of the present invention are shown below.

[0027] Figure 2 Images of single-crystal gallium electrodes: (a) square electrode, (b) circular electrode;

[0028] Figure 3 Hydrogen evolution electrode potential curves of single-crystal gallium electrodes with different crystallographic orientations in alkaline solution;

[0029] Figure 4 Gallium deposition electrode potential curves of single-crystal gallium electrodes with different crystallographic orientations in gallium-containing alkaline solutions;

[0030] Figure 5 This is a comparison of the current efficiency of single-crystal gallium electrodes and polycrystalline gallium electrodes with different crystallographic orientations. Detailed Implementation

[0031] The first aspect of this invention provides an application of a single-crystal gallium electrode in electrolytic refining. Single-crystal gallium, after being acid-washed with a 5% HCl solution for 1 minute, is used as the cathode, and crude gallium is used as the anode. The cathode and anode are placed in an electrolyte containing 2.0 mol / L to 6.0 mol / L NaOH and 20 g / L to 80 g / L sodium gallate. The electrode distance is set to 20 mm to 60 mm, and the refining process is carried out at 5°C to 28°C with a current density of 100 A / m. 2 ~1000A / m 2 Electrolysis is performed under the following conditions to obtain refined gallium. Among them, the crystal orientation of the single crystal gallium electrode is one of (111), (102), (200), (113), (211).

[0032] This invention provides an application of a single-crystal gallium electrode in electrolytic refining, comprising a solid-state electrolytic refining process using single-crystal gallium with a specific crystal orientation as the cathode and crude gallium as the anode in a low-temperature alkaline electrolyte system. By utilizing the ordered atomic arrangement on the single-crystal surface and the anisotropic growth kinetics of specific crystal planes, dendrite growth and impurity adsorption during electrolysis are suppressed, thereby significantly improving the current efficiency and product density of gallium while maintaining the solid crystal structure.

[0033] A second aspect of the present invention provides a method for preparing a single-crystal gallium electrode, comprising the following steps:

[0034] Step 1. Melt metallic gallium with a purity not lower than that of the target electrode and transfer it to a plastic tray. Place the plastic tray in a low-temperature blower incubator, refrigerator, or other equipment that can achieve an incubation temperature not higher than 0°C for cooling to obtain liquid gallium. The plastic tray is specifically made of one of the commercially available polytetrafluoroethylene, polypropylene, or polyethylene.

[0035] Step 2. Graft the seed crystal with the target crystal orientation into liquid gallium, remove the surface gallium oxide film with a scraper, and cool and crystallize at 0℃~29℃ until the liquid gallium is completely crystallized along the seed crystal. The crystal orientation of the resulting gallium crystal is the same as that of the seed crystal. The crystal orientation of the seed crystal is one of (111), (102), (200), (113), and (211).

[0036] Step 3. Turn off the low-temperature incubator, remove the tray and demold to obtain the electrode blank;

[0037] Step 4. Wash the electrode blank with a dilute acid with a concentration of 0.1 mol / L to 5 mol / L to remove the gallium oxide film on the surface; wherein, the dilute acid is one of the pure aqueous solutions of hydrochloric acid, nitric acid, or sulfuric acid;

[0038] Step 5. Cut the acid-washed electrode blank according to the target electrode size to obtain single-crystal gallium electrodes of different specifications (e.g., Figure 2 (As shown).

[0039] The purity of the gallium metal used in preparing the single-crystal gallium electrode in this invention depends on the purity of the target product. For example, to produce 4N industrial gallium by electrolysis, at least 4N gallium is required to prepare the electrode. To produce 5N gallium by electrolysis, at least 5N gallium is required. To produce 6N high-purity gallium by electrolysis, at least 6N high-purity gallium is required. To produce 7N high-purity gallium by electrolysis, at least 7N high-purity gallium is required.

[0040] Example 1:

[0041] This embodiment provides an application of a (111) crystal gallium electrode in electrolytic refining. A (111) crystal gallium electrode, acid-washed with 5% HCl solution for 1 min, is used as the cathode, and crude gallium with a purity of 99.99% (4N) is used as the anode. The cathode and anode are placed in an electrolyte containing 4.0 mol / L NaOH and 50 g / L sodium gallate. The electrode distance is set to 40 mm, and the cooling circulation system is turned on. The refining process is carried out at 20°C and a current density of 300 A / m. 2 Under certain conditions, electrolysis for 24 hours yields refined gallium.

[0042] After electrolysis, the deposited layer on the cathode surface is smooth and bright, without any macroscopically visible dendrites. For example... Figure 3 , 4The graphs show the hydrogen evolution electrode potential (HEP) curves in alkaline solution and the gallium evolution electrode potential (GEP) curves in gallium-containing alkaline solution for a (111) crystallographically oriented single-crystal gallium electrode. The graphs indicate that the (111) plane, being a high-index plane, may have higher surface energy and more active sites, potentially leading to higher HER activity. However, the deposited gallium layer may have a coarser morphology or exhibit different textures. Current efficiency reaches over 98% (e.g., ...). Figure 5 (As shown).

[0043] The method for fabricating the (111) single-crystal gallium electrode used in this embodiment includes the following steps:

[0044] Step 1. Melt 4N metallic gallium at 30°C and transfer it to a polytetrafluoroethylene tray. Place the tray in a low-temperature forced-air incubator to cool to 28°C to obtain liquid gallium.

[0045] Step 2. Graft the seed crystal with crystal orientation (111) into liquid gallium, remove the surface gallium oxide film with a scraper, cool and crystallize at 28°C until the liquid gallium is completely crystallized along the seed crystal, and the crystal gallium formed has the same crystal orientation as the seed crystal.

[0046] Step 3. Turn off the low-temperature incubator, remove the tray and demold to obtain the electrode blank;

[0047] Step 4. Wash the electrode blank with 0.5 mol / L dilute hydrochloric acid to remove the gallium oxide film on the surface;

[0048] Step 5. Cut the acid-washed electrode blank to obtain a single-crystal gallium electrode with crystal orientation (111).

[0049] The fabricated single-crystal gallium electrode was tested by X-ray diffraction (XRD), and the results are as follows: Figure 1 As shown, only a very strong (111) characteristic peak is displayed at 30.24, indicating that the electrode prepared in this embodiment is a high-purity, grain boundary-free (111) single crystal gallium.

[0050] Example 2:

[0051] This embodiment provides an application of a (102) crystal gallium electrode in electrolytic refining. A (102) crystal gallium electrode, acid-washed with 5% HCl solution for 1 min, is used as the cathode, and crude gallium with a purity of 99.99% (4N) is used as the anode. The cathode and anode are placed in an electrolyte containing 5.0 mol / L NaOH and 60 g / L sodium gallate. The electrode distance is set to 40 mm, and the cooling circulation system is turned on. The refining process is carried out at 20°C and a current density of 400 A / m. 2 Under certain conditions, electrolysis for 24 hours yields refined gallium.

[0052] After electrolysis, the deposited layer on the cathode surface is smooth and bright, without any macroscopically visible dendrites. For example... Figure 3 , 4 As can be seen from the hydrogen evolution electrode potential curves of the (102) crystallographically oriented single-crystal gallium electrode in alkaline solution and the gallium deposition electrode potential curves in gallium-containing alkaline solution, the step structure is conducive to nucleation, which may enable gallium deposition to start at a milder potential, saving energy. The abundant step edges can serve as a continuous growth front, and after reaching a certain overpotential, they may exhibit a higher deposition current. The current efficiency reaches over 98% (e.g., Figure 5 (As shown).

[0053] The method for fabricating the (102) single-crystal gallium electrode used in this embodiment includes the following steps:

[0054] Step 1. Melt 5N metallic gallium at 40°C and transfer it to a polytetrafluoroethylene tray. Place the tray in a low-temperature forced-air incubator to cool to 25°C to obtain liquid gallium.

[0055] Step 2. Graft the seed crystal with crystal orientation (102) into liquid gallium, remove the surface gallium oxide film with a scraper, cool and crystallize at 25°C until the liquid gallium is completely crystallized along the seed crystal, and the crystal gallium formed has the same crystal orientation as the seed crystal.

[0056] Step 3. Turn off the low-temperature incubator, remove the tray and demold to obtain the electrode blank;

[0057] Step 4. Wash the electrode blank with 1 mol / L dilute hydrochloric acid to remove the gallium oxide film on the surface;

[0058] Step 5. Cut the acid-washed electrode blank to obtain a single-crystal gallium electrode with crystal orientation (102).

[0059] The fabricated single-crystal gallium electrode was tested by X-ray diffraction (XRD), and the results are as follows: Figure 1 As shown, only a very strong (102) characteristic peak is displayed at 30.53, indicating that the electrode prepared in this embodiment is a high-purity, grain boundary-free (102) single crystal gallium.

[0060] Example 3:

[0061] This embodiment provides an application of a (200) oriented single-crystal gallium electrode in electrolytic refining. A (200) oriented single-crystal gallium electrode, after being acid-washed with 5% HCl solution for 1 min, is used as the cathode. Crude gallium with a purity of 99.99% (4N) is used as the anode. The cathode and anode are placed in an electrolyte containing 7.0 mol / L NaOH and 50 g / L sodium gallate. The electrode distance is set to 30 mm, and the cooling circulation system is activated at 20°C and a current density of 300 A / m. 2 Under suitable conditions, electrolysis for 24 hours yielded refined gallium. After electrolysis, the deposited layer on the cathode surface was smooth and bright, without any macroscopically visible dendrites. Figure 3 , 4 The graphs show the hydrogen evolution electrode potential curves in alkaline solutions and gallium evolution electrode potential curves in gallium-containing alkaline solutions for a single-crystal gallium electrode with a crystal orientation of (200). The graphs suggest that the catalytic activity of the hydrogen evolution reaction may be weak, with a high overpotential. The current efficiency reaches over 98% (e.g., ...). Figure 5 (As shown).

[0062] The method for fabricating the (200) crystal gallium electrode used in this embodiment includes the following steps:

[0063] Step 1. Melt 6N metallic gallium at 50°C and transfer it to a polytetrafluoroethylene tray. Place the tray in a low-temperature forced-air incubator to cool to 15°C to obtain liquid gallium.

[0064] Step 2. Graft the seed crystal with crystal orientation (200) into liquid gallium, remove the surface gallium oxide film with a scraper, cool and crystallize at 15°C until the liquid gallium is completely crystallized along the seed crystal, and the crystal gallium formed has the same crystal orientation as the seed crystal.

[0065] Step 3. Turn off the low-temperature incubator, remove the tray and demold to obtain the electrode blank;

[0066] Step 4. Wash the electrode blank with 2.5 mol / L dilute hydrochloric acid to remove the gallium oxide film on the surface;

[0067] Step 5. Cut the acid-washed electrode blank to obtain a single-crystal gallium electrode with a crystal orientation of (200).

[0068] The fabricated single-crystal gallium electrode was tested by X-ray diffraction (XRD), and the results are as follows: Figure 1 As shown, only a very strong (200) characteristic peak is displayed at 39.8, indicating that the electrode prepared in this embodiment is a high-purity, grain boundary-free (200) single crystal gallium.

[0069] Example 4:

[0070] This embodiment provides an application of a (113) crystal gallium electrode in electrolytic refining. A (113) crystal gallium electrode, after being acid-washed with 5% HCl solution for 1 min, is used as the cathode, and crude gallium with a purity of 99.99% (4N) is used as the anode. The cathode and anode are placed in an electrolyte containing 5.0 mol / L NaOH and 40 g / L sodium gallate. The electrode distance is set to 40 mm, and the cooling circulation system is turned on. The refining process is carried out at 20°C and a current density of 400 A / m. 2 Under suitable conditions, electrolysis for 24 hours yielded refined gallium. After electrolysis, the deposited layer on the cathode surface was smooth and bright, without any macroscopically visible dendrites. Figure 3 , 4The hydrogen evolution potential curves of the (113) crystallographically oriented single-crystal gallium electrode in alkaline solution and gallium evolution potential curves in gallium-containing alkaline solution can be seen from the figures. It can be seen that the hydrogen evolution potential of the (113) crystal plane is lower, indicating that this crystal plane has better catalytic activity for HER; conversely, it may have lower activity. The current efficiency reaches over 98% (e.g., Figure 5 (As shown).

[0071] The method for fabricating the single-crystal gallium electrode with crystal orientation (113) used in this embodiment includes the following steps:

[0072] Step 1. Melt 7N metallic gallium at 60°C and transfer it to a polytetrafluoroethylene tray. Place the tray in a low-temperature forced-air incubator to cool to 10°C to obtain liquid gallium.

[0073] Step 2. Graft the seed crystal with crystal orientation (113) into liquid gallium, remove the surface gallium oxide film with a scraper, cool and crystallize at 10°C until the liquid gallium is completely crystallized along the seed crystal, and the crystal gallium formed has the same crystal orientation as the seed crystal.

[0074] Step 3. Turn off the low-temperature incubator, remove the tray and demold to obtain the electrode blank;

[0075] Step 4. Wash the electrode blank with 3 mol / L dilute hydrochloric acid to remove the gallium oxide film on the surface;

[0076] Step 5. Cut the acid-washed electrode blank to obtain a single-crystal gallium electrode with crystal orientation (113).

[0077] The fabricated single-crystal gallium electrode was tested by X-ray diffraction (XRD), and the results are as follows: Figure 1 As shown, only a very strong (113) characteristic peak is displayed at 45.4, indicating that the electrode prepared in this embodiment is a high-purity, grain boundary-free (113) single crystal gallium.

[0078] Example 5:

[0079] This embodiment provides an application of a (211) crystal gallium electrode in electrolytic refining. A (211) crystal gallium electrode, acid-washed with 5% HCl solution for 1 min, is used as the cathode, and crude gallium with a purity of 99.99% (4N) is used as the anode. The cathode and anode are placed in an electrolyte containing 6.0 mol / L NaOH and 30 g / L sodium gallate. The electrode distance is set to 30 mm, and the cooling circulation system is turned on. The refining process is carried out at 20°C and a current density of 300 A / m. 2 Under suitable conditions, electrolysis for 24 hours yielded refined gallium. After electrolysis, the deposited layer on the cathode surface was smooth and bright, without any macroscopically visible dendrites. Figure 3 , 4The graphs show the hydrogen evolution electrode potential curves in alkaline solutions and gallium evolution electrode potential curves in gallium-containing alkaline solutions for single-crystal gallium electrodes with a (211) crystal orientation. It can be seen from the graphs that, among all crystal planes, the (211) orientation single-crystal gallium electrode is likely to begin significant gallium deposition at the most positive potential, exhibiting extremely high nucleation efficiency. The current efficiency reaches over 98% (e.g., ...). Figure 5 (As shown).

[0080] The method for fabricating the (211) single-crystal gallium electrode used in this embodiment includes the following steps:

[0081] Step 1. Melt 6N metallic gallium at 45°C and transfer it to a polytetrafluoroethylene tray. Place the tray in a low-temperature forced-air incubator to cool to 5°C to obtain liquid gallium.

[0082] Step 2. Graft the seed crystal with crystal orientation (211) into liquid gallium, remove the surface gallium oxide film with a scraper, cool and crystallize at 5°C until the liquid gallium is completely crystallized along the seed crystal, and the crystal gallium formed has the same crystal orientation as the seed crystal.

[0083] Step 3. Turn off the low-temperature incubator, remove the tray and demold to obtain the electrode blank;

[0084] Step 4. Wash the electrode blank with 5 mol / L dilute hydrochloric acid to remove the gallium oxide film on the surface;

[0085] Step 5. Cut the acid-washed electrode blank to obtain a single-crystal gallium electrode with crystal orientation (211).

[0086] The obtained single-crystal gallium electrode was tested by X-ray diffraction (XRD), and only a very strong (211) characteristic peak was observed at 46.3, indicating that the electrode obtained in this embodiment is a high-purity, grain boundary-free (211) single-crystal gallium.

[0087] X-ray diffraction was used to characterize the crystal orientation of the single-crystal gallium electrodes with different crystal orientations prepared in Examples 1-5 of this invention. The results are as follows: Figure 1 As shown, by comparing polycrystalline gallium electrodes, standard PDF cards, and five different orientations of single-crystal gallium electrodes, it is clearly demonstrated that the prepared single-crystal electrodes have extremely high single orientation and good crystal quality.

[0088] The above-described embodiments are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make other improvements without departing from the principle of the present invention, and these improvements should be considered within the scope of protection of the present invention.

Claims

1. An application of a single-crystal gallium electrode in electrolytic refining, characterized in that, The crystal orientation of the single-crystal gallium electrode is one of (111), (102), (200), (113), and (211), and the application process is as follows: The single-crystal gallium electrode is acid-washed and used as the cathode, while crude gallium is used as the anode. The cathode and anode are placed in an electrolyte and electrolyzed within a set temperature range to obtain refined gallium.

2. The application of a single-crystal gallium electrode according to claim 1 in electrolytic refining, characterized in that, During electrolysis, the electrolysis temperature is 5℃~28℃, and the current density is 100A / m. 2 ~1000A / m 2 .

3. The application of a single-crystal gallium electrode according to claim 1 or 2 in electrolytic refining, characterized in that, The electrolyte contains 2.0 mol / L to 6.0 mol / L NaOH and 20 g / L to 80 g / L sodium gallate.

4. The application of a single-crystal gallium electrode according to claim 1 or 2 in electrolytic refining, characterized in that, The pickling process involves washing with a 5% HCl solution for 1 minute. During electrolysis, the electrode distance is 20mm~60mm.

5. A method for fabricating a single-crystal gallium electrode to achieve the application described in claim 1, characterized in that, Includes the following steps: Step 1. After melting metallic gallium, transfer it to a plastic tray, place the plastic tray in a low-temperature incubator to cool it, and obtain liquid gallium; Step 2. Graft the seed crystal of the target crystal orientation into liquid gallium, remove the surface gallium oxide film with a scraper, and then cool and crystallize until the liquid gallium is completely crystallized along the seed crystal; Step 3. Turn off the low-temperature incubator, remove the tray and demold to obtain the electrode blank; Step 4. Wash the electrode blank with dilute acid to remove the gallium oxide film on the surface; Step 5. Cut the acid-washed electrode blank according to the target electrode size to obtain the single-crystal gallium electrode.

6. The method for fabricating a single-crystal gallium electrode according to claim 5, characterized in that, In step 2, the crystal orientation of the seed crystal is one of (111), (102), (200), (113), (211); the crystal orientation of the crystal gallium formed by the liquid gallium crystallizing outward along the seed gallium is the same as that of the seed crystal.

7. The method for fabricating a single-crystal gallium electrode according to claim 5, characterized in that, The plastic pallet is made of one of the commercially available materials: polytetrafluoroethylene, polypropylene, or polyethylene.

8. The method for fabricating a single-crystal gallium electrode according to claim 5, characterized in that, In step 1, the purity of the metallic gallium electrode is not lower than the purity of gallium in the target gallium electrode.

9. The method for fabricating a single-crystal gallium electrode according to claim 5, characterized in that, The cooling crystallization temperature is 0℃~29℃; Low-temperature incubators are low-temperature blower incubators, refrigerators, or other equipment that can achieve an incubation temperature not exceeding 0°C.

10. A method for fabricating a single-crystal gallium electrode according to claim 5, characterized in that, In step 4, the dilute acid is one of the pure aqueous solutions of hydrochloric acid, nitric acid, or sulfuric acid, with a concentration of 0.1 mol / L to 5 mol / L.

Images