A method for electrochemically preparing gallium oxyhydroxide

Abstract

The application belongs to the technical field of non-ferrous metallurgy, and particularly relates to a method for electrochemically preparing gallium oxyhydroxide. The method for preparing gallium oxyhydroxide is scientific and reasonable in design. The method uses metallic gallium as an anode, carries out direct electrolysis in deionized water, and prepares high-purity gallium oxyhydroxide powder material in one step. The technical scheme can overcome problems of a long existing gallium oxyhydroxide preparation process, large reagent consumption, high requirement for equipment, and difficulty in meeting product purity and physical specifications, and has the characteristics of short process, high efficiency, simple operation, low requirement for equipment, low cost, high product purity, etc. The prepared gallium oxyhydroxide powder has uniform particle size and micro-morphology, and is an excellent precursor for producing fourth-generation semiconductor materials.

Description

Technical Field

[0001] This invention belongs to the field of non-ferrous metal metallurgy technology, specifically relating to a method for the electrochemical preparation of gallium hydroxyoxide. Background Technology

[0002] Gallium oxide (Ga2O3) is a transparent, ultra-wide bandgap oxide semiconductor material with a bandgap of 4.9-5.3 eV and a breakdown electric field strength of 8 MV / cm, far exceeding those of gallium nitride (3.4 eV, 3.3 MV / cm), gallium arsenide (1.4 eV, 0.4 MV / cm), silicon (1.1 eV, 0.3 MV / cm), and silicon carbide (3.3 eV, 2.5 MV / cm). Furthermore, gallium oxide possesses unique ultraviolet (UV) transmittance (over 80%), low energy loss, high chemical stability, and high thermal stability, making it a preferred semiconductor material for manufacturing solar-blind UV photodetectors, high-temperature, high-frequency, high-power microelectronic devices, and UV-transparent conductive electrodes.

[0003] Gallium oxide (GaO), as the latest fourth-generation ultra-wide bandgap semiconductor material, plays an irreplaceable role in high-tech industries such as information, energy, defense, transportation, and manufacturing. The production of high-purity GaO typically uses high-purity metallic gallium or gallium salts as raw materials. First, a GaO precursor with chemical purity and physical specifications meeting requirements is prepared, followed by high-temperature calcination to obtain high-purity GaO. Therefore, preparing qualified GaO is a necessary condition and core technology for GaO production.

[0004] A search revealed that Chinese patent application No. 201210542115.4 discloses a method for the electrochemical preparation of gallium hydroxyl oxide. This method involves using metallic gallium as the anode in an alkaline electrolyte solution for three-stage electrolysis to obtain a sodium gallate solution, followed by neutralization, washing, and drying to obtain gallium hydroxyl oxide. While this method can yield a high-purity product, the process of electrolyzing metallic gallium to obtain a sodium gallate solution, followed by neutralization and precipitation of gallium hydroxyl oxide, is not only lengthy and complex but also energy-intensive, resulting in poor economic efficiency.

[0005] Chinese patent application No. 201810752162.9 discloses a method for preparing gallium oxide, which involves reacting gallium metal with sulfuric acid and hydrogen peroxide as solvents to generate a gallium sulfate solution, followed by further crystallization to precipitate gallium sulfate crystals, and then calcining at high temperature to obtain gallium oxide powder. This method uses sulfuric acid, which has relatively low reactivity, requiring the addition of hydrogen peroxide during leaching to promote the dissolution of gallium metal, resulting in high reagent costs. Furthermore, the high-temperature calcination of gallium sulfate to prepare gallium oxide generates SO2 fumes, posing a significant environmental challenge.

[0006] Chinese patent applications No. 201711418839.7 and 201710311705.9 disclose methods for preparing gallium hydroxyl oxide from gallium metal. Preferably, nitric acid is used as a solvent to react with gallium metal to generate a gallium nitrate solution, and then an alkaline solution is added dropwise to the solution for neutralization. After aging, gallium hydroxyl oxide powder is obtained. Based on this, Chinese patent application No. 202010436819.8 proposes to add surfactants such as dodecylbenzenesulfonic acid in the gallium nitrate solution preparation stage to promote the neutralization and precipitation of gallium hydroxyl oxide in the next stage. All three applications are based on the basic idea of ​​preparing gallium hydroxyl oxide by acid dissolution and alkali neutralization of gallium metal. This involves the consumption of a large amount of acid and alkali reagents, which not only results in high reagent costs and easy introduction of impurities, affecting product purity, but also makes it impossible to recover the acid and alkali and generate high-salt wastewater that is difficult to treat.

[0007] Chinese patent application No. 201210313080.7 discloses a method for preparing gallium hydroxy oxide nanocrystals. Using a benzene-saturated solution of gallium chloride and hexadecyltrimethylammonium bromide as raw materials, the mixture is reacted in a high-pressure reactor at a temperature of 160-200℃ for 10-18 hours, successfully obtaining gallium hydroxy oxide nanocrystals. However, this method has high energy consumption, high equipment requirements, and easily generates difficult-to-treat organic wastewater, resulting in significant environmental pressure.

[0008] Chinese patent applications Nos. 201910971014.0 and 201510835364.6 disclose a short-process method for preparing gallium hydroxyl oxide based on hydrothermal reaction. Gallium hydroxyl oxide powder is obtained by directly reacting metallic gallium with water. However, the reaction between metallic gallium and water needs to be carried out under high temperature and high pressure conditions above 150°C, which not only consumes a lot of energy but also requires costly pressure reaction equipment. Moreover, mechanical stirring cannot fully disperse and mix the liquid metallic gallium, making it difficult to carry out the hydrothermal reaction completely and failing to obtain gallium hydroxyl oxide powder material with uniform morphology and size.

[0009] In conclusion, there is still considerable room for optimization and improvement in existing gallium hydroxyl oxide (GaOH) fabrication processes. It is necessary to further develop GaOH fabrication technologies that are simple to operate, have short processes, low costs, and are environmentally friendly to support the high-quality development of the fourth-generation semiconductor industry. Summary of the Invention

[0010] The purpose of this invention is to overcome the problems of existing gallium hydroxyl oxide preparation processes, such as long process flow, large reagent consumption, high equipment requirements, and difficulty in achieving product purity and physical specifications. This invention provides an electrochemical method for preparing gallium hydroxyl oxide. The process technology of this invention features a short process flow, high efficiency, simple operation, low equipment requirements, low cost, and high product purity. The prepared gallium hydroxyl oxide powder has uniform particle size and microstructure, making it an excellent precursor for the production of fourth-generation semiconductor materials.

[0011] To achieve the above-mentioned technical objectives and effects, the present invention is implemented through the following technical solution:

[0012] An electrochemical method for preparing gallium hydroxyoxide involves using metallic gallium as the anode and performing direct current electrolysis in deionized water to prepare high-purity gallium hydroxyoxide powder material in one step.

[0013] Furthermore, the specific process operation of the electrochemical preparation method of gallium hydroxyl oxide as described above is as follows:

[0014] 1) Add metallic gallium to deionized water in the specified proportion;

[0015] 2) Under normal pressure, the system is heated to a predetermined temperature, and direct current electrolysis is performed with liquid gallium metal as the anode to cause electrochemical oxidation of gallium metal, which directly reacts in deionized water to generate gallium hydroxyoxide.

[0016] 3) After the reaction is complete, the resulting slurry mixture is filtered to achieve solid-liquid separation;

[0017] 4) The filter residue is dried to obtain high-purity gallium hydroxyl oxide powder material.

[0018] Furthermore, in the electrochemical preparation of gallium hydroxyl oxide method described above, in step 1), the purity of gallium metal is above 4N, and the mass ratio of deionized water to gallium metal is controlled at 3-30:1.

[0019] Furthermore, in the electrochemical preparation of gallium hydroxyl oxide method described above, in step 2), the electrolytic cell is made of graphite and is connected to the power supply via copper wires. During the electrolysis process, liquid gallium metal exists at the bottom of the electrolytic cell. The liquid gallium metal is connected to the power supply through direct contact with the graphite electrolytic cell, thus becoming the anode of the electrolysis system.

[0020] Furthermore, in the electrochemical preparation of gallium hydroxyl oxide method described above, step 2) uses one of an aluminum plate, a stainless steel plate, a titanium plate, or a copper plate as the cathode.

[0021] Furthermore, in the electrochemical preparation of gallium hydroxyl oxide method described above, in step 2), the reaction temperature is controlled at 25-95℃, the reaction time is controlled at 3-24h, and the DC voltage is controlled at 0.2-1.0V.

[0022] Furthermore, in the electrochemical preparation of gallium hydroxyl oxide method described above, in step 3), the solid-liquid separation temperature is the same as the electrolysis temperature in step 2), and the filter residue is washed with deionized water 3-6 times.

[0023] Furthermore, in the electrochemical preparation of gallium hydroxyl oxide as described above, the filter residue is dried at 100-150℃ for 12-96 hours to obtain high-purity gallium hydroxyl oxide powder material.

[0024] The beneficial effects of this invention are:

[0025] 1. This invention uses metallic gallium and deionized water as raw materials to prepare high-purity gallium hydroxyl oxide powder material in one step through DC electrolysis. The process is short and efficient, and no chemical reagents such as acids and alkalis are required. This not only reduces costs but also significantly reduces the risk of introducing impurities into the raw materials, which is beneficial for obtaining high-purity products. The entire reaction process only consumes deionized water, and the chemical composition and pH of the electrolyte do not change. Therefore, there is no need to adjust the electrolyte composition during electrolysis, making the operation simple and easy to automate.

[0026] 2. This invention enables gallium to undergo electrochemical oxidation preferentially at the anode by precisely controlling electrochemical conditions, which is then further hydrolyzed to generate gallium hydroxyl oxide. Most of the impurities contained in the gallium at the anode have a more positive potential than gallium. By controlling the electrolysis conditions, the impurities cannot undergo electrochemical oxidation. This achieves efficient and short-process preparation of gallium hydroxyl oxide while further removing impurities and improving product purity.

[0027] 3. In the electrolysis process of this invention, gallium preferentially reacts at the liquid-liquid interface between liquid gallium metal and deionized water to generate gallium hydroxyoxide. As the electrolysis process proceeds, the metallic gallium continuously and stably converts to gallium hydroxyoxide until the reaction is complete, resulting in a high conversion rate. In addition, under a stable electric field environment, the nascent gallium ions at the anode undergo in-situ hydrolysis to generate nanoscale gallium hydroxyoxide powder with uniform microstructure and particle size. Moreover, the particle size of the product can be controlled by the electric field strength, thereby ultimately obtaining a gallium hydroxyoxide precursor that meets the requirements for the production of fourth-generation semiconductor materials in terms of both chemical purity and physical specifications.

[0028] Of course, any product implementing this invention does not necessarily need to achieve all of the above advantages at the same time. Detailed Implementation

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] This invention discloses an electrochemical method for preparing gallium hydroxyl oxide, belonging to the field of non-ferrous metal metallurgy technology. The method uses metallic gallium as the anode and performs direct current electrolysis in deionized water to prepare high-purity gallium hydroxyl oxide powder in one step. This invention features a short process, high efficiency, simple operation, low equipment requirements, low cost, and high product purity. The prepared gallium hydroxyl oxide powder has uniform particle size and microstructure, making it an excellent precursor for the production of fourth-generation semiconductor materials.

[0031] The production process of this invention specifically includes the following steps:

[0032] 1) Add metallic gallium with a purity of 4N or higher and deionized water to the graphite electrolytic cell in a certain proportion, and control the mass ratio of deionized water to metallic gallium between 3:1 and 30:1.

[0033] 2) Connect the electrolytic cell to a DC power supply using copper wires, with liquid gallium metal as the anode and one of aluminum plate, stainless steel plate, titanium plate or copper plate as the cathode. Electrolyze for 3-24 hours at a temperature of 25-95℃ and a cell voltage of 0.2-1.0V, so that the gallium metal undergoes electrochemical oxidation and reacts directly in deionized water to generate gallium hydroxyoxide.

[0034] 3) After the reaction is complete, the resulting slurry mixture is filtered at a temperature of 25-95℃ (the same as the electrolysis process temperature) to achieve solid-liquid separation. The filter residue is washed with deionized water 3-6 times.

[0035] 4) Dry the filter residue at 100-150℃ for 12-96 hours to obtain high-purity gallium hydroxyl oxide powder material.

[0036] The present invention will be further described below with reference to specific embodiments.

[0037] Example 1

[0038] This embodiment provides a method for the electrochemical preparation of gallium hydroxyl oxide, specifically including the following steps:

[0039] 1) Add 4N pure gallium metal and deionized water to the graphite electrolytic cell in a certain proportion, and control the mass ratio of deionized water to gallium metal to be 3:1.

[0040] 2) The electrolytic cell is connected to a DC power supply using copper wires. Liquid gallium is used as the anode and an aluminum plate as the cathode. Electrolysis is carried out for 24 hours at a temperature of 25℃ and a cell voltage of 0.2V, so that the gallium undergoes electrochemical oxidation and reacts directly in deionized water to generate gallium hydroxyl oxide.

[0041] 3) After the reaction is complete, the resulting mixture is filtered at 25°C to achieve solid-liquid separation. The filter residue is washed three times with deionized water.

[0042] 4) Dry the filter residue at 100℃ for 96 hours to obtain high-purity gallium hydroxyl oxide powder material.

[0043] Using the processing method of this embodiment, the conversion rate and product purity of gallium hydroxyl oxide were analyzed by dissolving it in aqua regia combined with inductively coupled plasma mass spectrometry (ICP-MS). The results showed that the conversion rate of metallic gallium to gallium hydroxyl oxide was 99.12%, and the purity of the gallium hydroxyl oxide product was 99.998%.

[0044] Example 2

[0045] This embodiment provides a method for the electrochemical preparation of gallium hydroxyl oxide, specifically including the following steps:

[0046] 1) Add 4N pure gallium metal and deionized water to the graphite electrolytic cell in a certain proportion, and control the mass ratio of deionized water to gallium metal to be 30:1.

[0047] 2) The electrolytic cell is connected to a DC power supply using copper wires. Liquid gallium is used as the anode and a copper plate as the cathode. Electrolysis is carried out for 3 hours at a temperature of 95℃ and a cell voltage of 1.0V, so that the gallium undergoes electrochemical oxidation and reacts directly in deionized water to generate gallium hydroxyoxide.

[0048] 3) After the reaction is complete, the resulting mixture is filtered at 95°C to achieve solid-liquid separation. The filter residue is washed 6 times with deionized water.

[0049] 4) Dry the filter residue at 150℃ for 12 hours to obtain high-purity gallium hydroxyl oxide powder material.

[0050] Using the processing method of this embodiment, the conversion rate and product purity of gallium hydroxyl oxide were analyzed by dissolving it in aqua regia combined with inductively coupled plasma mass spectrometry (ICP-MS). The results showed that the conversion rate of metallic gallium to gallium hydroxyl oxide was 99.36%, and the purity of the gallium hydroxyl oxide product was 99.996%.

[0051] Example 3

[0052] This embodiment provides a method for the electrochemical preparation of gallium hydroxyl oxide, specifically including the following steps:

[0053] 1) Add 4N pure gallium metal and deionized water to the graphite electrolytic cell in a certain proportion, and control the mass ratio of deionized water to gallium metal to be 10:1.

[0054] 2) The electrolytic cell is connected to a DC power supply using copper wires. Liquid gallium is used as the anode and a stainless steel plate as the cathode. Electrolysis is carried out for 8 hours at a temperature of 35℃ and a cell voltage of 0.4V, so that the gallium undergoes electrochemical oxidation and reacts directly in deionized water to generate gallium hydroxyl oxide.

[0055] 3) After the reaction is complete, the resulting mixture is filtered at 35°C to achieve solid-liquid separation. The filter residue is washed four times with deionized water.

[0056] 4) Dry the filter residue at 110℃ for 24 hours to obtain high-purity gallium hydroxyl oxide powder material.

[0057] Using the processing method of this embodiment, the conversion rate and product purity of gallium hydroxyl oxide were analyzed by dissolving it in aqua regia combined with inductively coupled plasma mass spectrometry (ICP-MS). The results showed that the conversion rate of metallic gallium to gallium hydroxyl oxide was 99.56%, and the purity of the gallium hydroxyl oxide product was 99.997%.

[0058] Example 4

[0059] This embodiment provides a method for the electrochemical preparation of gallium hydroxyl oxide, specifically including the following steps:

[0060] 1) Add 4N pure gallium metal and deionized water to the graphite electrolytic cell in a certain proportion, and control the mass ratio of deionized water to gallium metal to be 20:1.

[0061] 2) The electrolytic cell is connected to a DC power supply using copper wires. Liquid gallium is used as the anode and a titanium plate as the cathode. Electrolysis is carried out for 12 hours at a temperature of 55℃ and a cell voltage of 0.6V, so that the gallium metal undergoes electrochemical oxidation and reacts directly in deionized water to generate gallium hydroxyl oxide.

[0062] 3) After the reaction is complete, the resulting mixture is filtered at 55°C to achieve solid-liquid separation. The filter residue is washed 5 times with deionized water.

[0063] 4) Dry the filter residue at 120℃ for 48 hours to obtain high-purity gallium hydroxyl oxide powder material.

[0064] Using the processing method of this embodiment, the conversion rate and product purity of gallium hydroxyl oxide were analyzed by dissolving it in aqua regia combined with inductively coupled plasma mass spectrometry (ICP-MS). The results showed that the conversion rate of metallic gallium to gallium hydroxyl oxide was 99.38%, and the purity of the gallium hydroxyl oxide product was 99.995%.

[0065] Example 5

[0066] This embodiment provides a method for the electrochemical preparation of gallium hydroxyl oxide, specifically including the following steps:

[0067] 1) Add 4N pure gallium metal and deionized water to the graphite electrolytic cell in a certain proportion, and control the mass ratio of deionized water to gallium metal to be 25:1.

[0068] 2) The electrolytic cell is connected to a DC power supply using copper wires. Liquid gallium is used as the anode and an aluminum plate as the cathode. Electrolysis is carried out for 18 hours at a temperature of 75℃ and a cell voltage of 0.8V, so that the gallium undergoes electrochemical oxidation and reacts directly in deionized water to generate gallium hydroxyl oxide.

[0069] 3) After the reaction is complete, the resulting slurry mixture is filtered at 75°C to achieve solid-liquid separation. The filter residue is washed three times with deionized water.

[0070] 4) Dry the filter residue at 135℃ for 72 hours to obtain high-purity gallium hydroxyl oxide powder material.

[0071] Using the processing method of this embodiment, the conversion rate and product purity of gallium hydroxyl oxide were analyzed by dissolving it in aqua regia combined with inductively coupled plasma mass spectrometry (ICP-MS). The results showed that the conversion rate of metallic gallium to gallium hydroxyl oxide was 99.69%, and the purity of the gallium hydroxyl oxide product was 99.998%.

[0072] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for the electrochemical preparation of gallium hydroxyl oxide, characterized in that: High-purity gallium hydroxyl oxide powder material is prepared in one step by direct current electrolysis in deionized water using metallic gallium as the anode; the specific process operation is as follows: 1) Add metallic gallium to deionized water in the specified proportion; 2) Under normal pressure, the system is heated to a predetermined temperature, and direct current electrolysis is performed using liquid gallium metal as the anode to cause electrochemical oxidation of gallium metal, which directly reacts in deionized water to generate gallium hydroxyl oxide; in step 2), the DC voltage is controlled between 0.2-1.0V; 3) After the reaction is complete, the resulting slurry mixture is filtered to achieve solid-liquid separation; 4) The filter residue is dried to obtain high-purity gallium hydroxyl oxide powder material.

2. The method for electrochemical preparation of gallium hydroxyl oxide according to claim 1, characterized in that: In step 1), the purity of gallium is above 4N, and the mass ratio of deionized water to gallium is controlled at 3-30:

1.

3. The method for electrochemical preparation of gallium hydroxyl oxide according to claim 1, characterized in that: In step 2), the electrolytic cell is made of graphite and is connected to the power supply via copper wires. During the electrolysis process, liquid gallium metal exists at the bottom of the electrolytic cell. The liquid gallium metal is connected to the power supply through direct contact with the graphite electrolytic cell and becomes the anode of the electrolysis system.

4. The method for electrochemical preparation of gallium hydroxyl oxide according to claim 1, characterized in that: In step 2), one of the following is used as the cathode: aluminum plate, stainless steel plate, titanium plate or copper plate.

5. The method for electrochemical preparation of gallium hydroxyl oxide according to claim 1, characterized in that: In step 2), the reaction temperature is controlled at 25-95℃ and the reaction time is controlled at 3-24h.

6. The method for electrochemical preparation of gallium hydroxyl oxide according to claim 1, characterized in that: In step 3), the solid-liquid separation temperature is the same as the electrolysis temperature in step 2), and the filter residue is washed with deionized water 3-6 times.

7. The method for electrochemical preparation of gallium hydroxyl oxide according to claim 1, characterized in that: In step 4), the filter residue is dried at 100-150℃ for 12-96 hours to obtain high-purity gallium hydroxyl oxide powder material.