Method and device for preparing high-purity indium powder through pulse electrolysis-ultrasonic synergistic effect

Abstract

The invention provides a method and device for preparing high-purity indium powder through the pulse electrolysis-ultrasonic synergistic effect, and belongs to the field of high-purity metal material preparation. The invention provides a method for preparing high-purity indium powder by utilizing a pulse electrolysis-ultrasonic synergistic effect, which comprises the following steps of: performing pulse electrolysis on electrolyte under an ultrasonic condition to obtain the high-purity indium powder, the pH (Potential of Hydrogen) value of the electrolyte is 2.0 to 3.5; the electrolyte comprises the following components: 30-80 g / L of indium salt, 80-120 g / L of chlorine salt and 0.5-1.5 g / L of an additive. Due to the fact that pulse electrolysis has a duty ratio, crystal nucleuses formed by electrolysis cannot grow in time in an oriented mode, the concentration of metal ions near an electrode is supplemented within the short opening time, and growth of the crystal nucleuses is facilitated. The pulse-ultrasonic coordination effect is adopted, stripping and self-assembly of particles are efficiently and timely promoted, agglomeration of the indium powder is prevented, and therefore the dispersity of the indium powder is improved.

Description

Technical Field

[0001] The present invention relates to the field of high-purity metal material preparation, and in particular to a method and device for preparing high-purity indium powder by utilizing pulse electrolysis-ultrasound synergy. Background Art

[0002] High-purity indium powder is widely used in industry and daily life. Adding a small amount of indium to precious metals or other non-ferrous metals can increase their strength and wear resistance. For example, in electronic pastes, it can reduce the sintering temperature of the paste; in alloys, it can improve the alloy's wear resistance; in coatings, it can improve transparency, wear resistance, scratch resistance, and electrical conductivity; in composite material curing agents, it can also serve as a heat dissipation material for electrical components, improving their heat dissipation. As a new electronic material, indium powder is primarily used in ITO targets, high-purity alloys, back-field aluminum pastes (silver pastes, aluminum pastes, etc.) for silicon solar cells (to improve photoelectric conversion efficiency), antistatic applications, and other electronic information, high-purity metal material preparation, and the nuclear industry.

[0003] Traditional methods for preparing indium powder include electrolysis, vacuum distillation, and atomization, but the above methods have problems of low purity and poor dispersibility. Summary of the Invention

[0004] The present invention provides a method and device for preparing high-purity indium powder by utilizing the synergistic effect of pulse electrolysis and ultrasound. The method of the present invention improves the purity and dispersibility of the indium powder.

[0005] The present invention provides a method for preparing high-purity indium powder, comprising the following steps:

[0006] Under ultrasonic conditions, the electrolyte is subjected to pulse electrolysis to obtain high-purity indium powder;

[0007] The pH value of the electrolyte is 2.0 to 3.5;

[0008] The electrolyte comprises the following components: 30-80 g / L of indium salt, 80-120 g / L of chloride salt and 0.5-1.5 g / L of additive.

[0009] Preferably, the indium salt includes indium sulfate and / or indium nitrate; the chloride salt includes sodium chloride and / or potassium chloride;

[0010] The additives include one or more of gelatin, β-naphthoic acid, polyvinyl pyrrolidone and polyacrylic acid.

[0011] Preferably, the current density of the pulse electrolysis is 100 to 250 A / m 2 , the pulse width is 4 to 10 ms, and the duty cycle is 30 to 50%.

[0012] Preferably, the temperature of the electrolyte during the pulse electrolysis process is 10-30°C

[0013] Preferably, the frequency of the ultrasound is 20 to 80 kHz.

[0014] Preferably, the direction of the electric field during the pulse electrolysis is perpendicular to the vibration direction of the ultrasound.

[0015] Preferably, after the pulse electrolysis is completed, the method further comprises: post-processing the obtained product to obtain the high-purity indium;

[0016] The post-processing includes: performing solid-liquid separation on the obtained product, and then washing and vacuum drying the obtained solid;

[0017] The vacuum drying comprises keeping the temperature at 40° C. for 1 to 2 hours, then heating the temperature to 80° C. for 2 to 3 hours, and then heating the temperature to 120° C. for 0.5 to 1 hour. The vacuum degree of the vacuum drying is ≤10 Pa.

[0018] The present invention also provides an electrolysis device used in the method described in the above technical solution, comprising a pulse power supply 1, a plurality of cathode sheets 2, a plurality of anode sheets 3, and an electrolytic cell 4;

[0019] The plurality of cathode sheets 2 and the plurality of anode sheets 3 are located in the electrolytic cell 4 and are perpendicular to the bottom of the electrolytic cell 4. The plurality of cathode sheets 2 are connected to the negative electrode of the pulse power supply 1 after being connected, and the plurality of anode sheets 3 are connected to the positive electrode of the pulse power supply 1 after being connected; an anode sheet is inserted into an adjacent cathode sheet among the plurality of cathode sheets 2;

[0020] It also includes: a multi-layer vibrating mesh spacer sheet located below the plurality of cathode sheets 2 and the plurality of anode sheets 3 and parallel to the bottom of the electrolytic cell 4; the bottoms of the plurality of cathode sheets 2 are embedded in the vibrating mesh spacer sheet adjacent thereto;

[0021] It also includes: an ultrasonic auxiliary unit vibration pool 9, an ultrasonic auxiliary unit system power supply 7 connected to the ultrasonic auxiliary unit vibration pool 9; the electrolytic cell 4 is located in the ultrasonic auxiliary unit vibration pool 9;

[0022] Low temperature circulation system 8; the ultrasonic auxiliary unit vibration pool 9 is located in the low temperature circulation system 8.

[0023] Preferably, the material of the plurality of cathode sheets 2 is titanium plate, the material of the plurality of anode sheets 3 is high-purity indium plate with a purity of ≥99.995%, and the distance between adjacent cathode sheets and anode sheets is 4-6 cm.

[0024] Preferably, the multi-layer vibrating mesh spacer sheet includes a first vibrating mesh spacer sheet 5 and a second vibrating mesh spacer sheet 6 located between the first vibrating mesh spacer sheet 5 and the electrolytic cell 4;

[0025] The mesh aperture of each layer of the multi-layer vibration mesh spacer sheet is independently 1 to 5 mm;

[0026] The low-temperature circulation system 8 uses a semiconductor refrigeration chip as a cold source and also includes a PID temperature controller and a thermocouple sensor, with a temperature control accuracy of +1°C.

[0027] Due to the duty cycle of pulse electrolysis, the crystal nuclei formed by electrolysis do not have time to grow in a directional manner, and under the action of ultrasound, the particle exfoliation and self-assembly are efficiently and timely promoted, preventing the agglomeration of indium powder, thereby improving its dispersion; and in a short opening time, the metal ion concentration near the electrode is replenished, and the impurity ions are kept away from the electrode surface, which is conducive to the growth of the crystal nuclei and improves the purity of the product.

[0028] Furthermore, during the pulse electrolysis process, additives are added to form a uniform physical / chemical protective layer on the electrode surface to inhibit the growth of dendrites, thereby preparing powders that meet certain particle size requirements and achieving efficient dispersion and morphology control of particles.

[0029] The cooling circulation system of the electrolysis device of the present invention can dynamically adjust the electrolyte temperature, facilitate the regulation of the electrolyte composition and maintain the constant electrolyte temperature during the electrolysis process, will not introduce other impurities and can balance the ion concentration in the electrolyte, thereby improving the quality and stability of the electrolysis product.

[0030] The ultrasonic-assisted system of the electrolysis device of the present invention accelerates the deposition rate of indium powder through cavitation effect, acoustic flow guidance and dynamic interaction regulation. The multi-stage vibrating mesh spacer significantly improves the particle size and speed, preventing indium from agglomerating due to its strong adhesiveness, thereby obtaining indium powder with good dispersion. It can achieve simultaneous purification and powdering, and ultimately obtain high-purity indium powder with a particle size of about 35 μm and a purity of more than 99.9999%.

[0031] The electrolysis device of the present invention is easy to realize the synergistic effect of multiple modules (electric pulse + ultrasound + low temperature + bipolar electrode), and enhance the complementary effect in the electrochemical process. The double-layer capacitor of pulse electrolysis is quickly charged and discharged, the interface ion concentration gradient increases, and the reaction rate is improved. Ultrasound assists in enhancing the mass transfer of the cavitation effect, destroying the diffusion layer and strengthening the mass transfer, while stripping the bubbles and sediments on the electrode surface. The ultrasonic vibration is synchronized with the electric pulse phase, and the two are coupled in time and space (synchronous cavitation peak during the pulse conduction period), maximizing the use of the high-pressure environment at the moment of cavitation bubble collapse to accelerate ion migration, avoid interference offset energy, reduce concentration polarization and activation energy, increase the reaction rate, reduce energy consumption, and extend the life of the electrode.

[0032] Therefore, the present invention is not only simple to operate, low in equipment cost, but also has high output, good dispersibility and is easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Schematic diagram of the structure of the electrolysis device used in the embodiment;

[0034] Figure 2 The indium powder prepared in Example 3;

[0035] Figure 3 The particle size distribution test results of the high-purity indium powder prepared in Example 1 are as follows;

[0036] Figure 4 This is a SEM image of the high-purity indium powder obtained in Example 1;

[0037] Figure 5 This is a SEM image of the high-purity indium powder obtained in Example 2;

[0038] Figure 6 This is the SEM image of the high-purity indium powder prepared in Example 3.

[0039] Figure 7 This is a SEM image of the high-purity indium powder obtained in Example 4;

[0040] Figure 8 This is the SEM image of the high-purity indium powder prepared in Example 5. DETAILED DESCRIPTION

[0041] The present invention provides a method for preparing high-purity indium powder, comprising the following steps:

[0042] Under ultrasonic conditions, the electrolyte is subjected to pulse electrolysis to obtain high-purity indium powder;

[0043] The pH value of the electrolyte is 2.0 to 3.5;

[0044] The electrolyte comprises the following components: 30-80 g / L of indium salt, 80-120 g / L of chloride salt and 0.5-1.5 g / L of additives.

[0045] In the present invention, the pH value of the electrolyte is 2.0-3.5. In a specific embodiment of the present invention, the pH value may be 2.4, 2.5, 2.8, 3 or 3.2.

[0046] In the present invention, the electrolyte includes 30 to 80 g / L of indium salt. In a specific embodiment of the present invention, the concentration of indium salt in the electrolyte can be 40 g / L, 50 g / L, 60 g / L or 70 g / L; the indium salt preferably includes indium sulfate and / or indium nitrate.

[0047] In the present invention, the electrolyte includes 80 to 120 g / L of chloride salt. In a specific embodiment of the present invention, the concentration of sodium chloride in the electrolyte can be 90 g / L, 100 g / L, 110 g / L or 115 g / L; the chloride salt preferably includes sodium chloride and / or potassium chloride.

[0048] In the present invention, the electrolyte includes 0.5 to 1.5 g / L of additives. In a specific embodiment of the present invention, the concentration of the additive in the electrolyte can be 0.6 g / L, 0.7 g / L, 0.8 g / L, 0.9 g / L or 1.2 g / L; the additive preferably includes one or more of gelatin, β-naphthoic acid, polyvinyl pyrrolidone and polyacrylic acid.

[0049] In the present invention, the current density of the pulse electrolysis is preferably 100 to 250 A / m 2 The pulse width is preferably 4 to 10 ms, the duty cycle is preferably 30 to 50%, and in a specific embodiment of the present invention, the current density can be 110 A / m 2 , 120A / m 2 , 130A / m 2 、140A / m 2 、150A / m 2 、160A / m 2 、170A / m 2 、180A / m 2 、190A / m 2 , 200A / m 2 , 210A / m 2 , 220A / m 2 , 230A / m 2 or 2400A / m 2 , the pulse width may be 7ms, 8ms or 9ms, and the duty cycle may be 35%, 40% or 45%.

[0050] In the present invention, the temperature of the electrolyte during the pulse electrolysis process is preferably 10-30°C. In a specific embodiment of the present invention, the temperature of the electrolyte may be 15°C, 20°C or 25°C. The frequency of the ultrasound is preferably 20-80kHz. In a specific embodiment of the present invention, the frequency of the ultrasound may be 30kHz, 40kHz, 50kHz, 60kHz or 70kHz.

[0051] In the present invention, the direction of the electric field during the pulse electrolysis is preferably perpendicular to the vibration direction of the ultrasound.

[0052] In the present invention, after the pulse electrolysis is completed, the process preferably further comprises: post-processing the obtained product to obtain the high-purity indium.

[0053] In the present invention, the post-treatment preferably includes: solid-liquid separation of the obtained product, and then washing and vacuum drying the obtained solid; the vacuum drying preferably includes keeping the temperature at 40°C for 1 to 2 hours, then heating to 80°C and keeping it for 2 to 3 hours, and then heating to 120°C and keeping it for 0.5 to 1 hour; the vacuum degree of the vacuum drying is preferably ≤10Pa.

[0054] The present invention also provides an electrolysis device used in the method described in the above technical solution, comprising a pulse power supply 1, a plurality of cathode sheets 2, a plurality of anode sheets 3, and an electrolytic cell 4;

[0055] Anode sheets are inserted into adjacent cathode sheets among the plurality of cathode sheets 2;

[0056] The plurality of cathode sheets 2 and the plurality of anode sheets 3 are located in the electrolytic cell 4 and are perpendicular to the bottom of the electrolytic cell 4. The plurality of cathode sheets 2 and the plurality of anode sheets 3 are connected to the negative electrode and the positive electrode of the pulse power supply, respectively.

[0057] It also includes: a multi-layer vibrating mesh spacer sheet located below the plurality of cathode sheets 2 and the plurality of anode sheets 3 and parallel to the bottom of the electrolytic cell 4; the bottoms of the plurality of cathode sheets 2 are embedded in the vibrating mesh spacer sheet adjacent thereto;

[0058] It also includes: an ultrasonic auxiliary unit vibration pool 9, an ultrasonic auxiliary unit system power supply 7 connected to the ultrasonic auxiliary unit vibration pool 9, and the electrolytic cell 4 is located in the ultrasonic auxiliary unit vibration pool 9;

[0059] Low temperature circulation system 8; the ultrasonic auxiliary unit vibration pool 9 is located in the low temperature circulation system 8.

[0060] In the present invention, the electrolysis device includes a pulse power supply 1 to provide power for pulse electrolysis.

[0061] In the present invention, the electrolysis device includes a plurality of cathode plates 2 , the material of the cathode plates 2 is preferably titanium plates, and the total number is preferably 5; anode plates are inserted between adjacent cathode plates in the cathode plates 2 .

[0062] In the present invention, the electrolysis device includes a plurality of anode sheets 3, each made of high-purity indium with a purity of ≥99.999%. The total number of anode sheets 3 is preferably five, and the spacing between adjacent cathode sheets is preferably 4 to 6 cm. The anode sheets are preferably of a convoluted, stepped design with a dense bottom and loose top. This ensures that the anode sheets are free of casting defects, refines the anode grain size, and concentrates some impurity elements near the hanging lugs, reducing the impurity element content within the effective area of ​​the anode sheet.

[0063] In the present invention, the electrolysis device includes an electrolytic cell 4 , and the plurality of cathode sheets 2 and the plurality of anode sheets 3 are located in the electrolytic cell 4 and are perpendicular to the bottom of the electrolytic cell 4 .

[0064] In the present invention, the electrolysis device includes a multi-layer vibrating mesh partition sheet located below the plurality of cathode sheets 2 and the plurality of anode sheets 3 and parallel to the bottom of the electrolytic cell 4; the bottoms of the plurality of cathode sheets 2 are embedded in the vibrating mesh partition sheet close to them; the multi-layer vibrating mesh partition sheet includes a first vibrating mesh partition sheet 5 and a second vibrating mesh partition sheet 6 located between the first vibrating mesh partition sheet 5 and the electrolytic cell 4; when the multi-layer vibrating mesh partition sheet includes the first vibrating mesh partition sheet 5 and the second vibrating mesh partition sheet 6, the bottoms of the plurality of cathode sheets 2 are embedded in the first vibrating mesh partition sheet 5; the mesh aperture of each layer of the vibrating mesh partition sheet in the multi-layer vibrating mesh partition sheet is independently 1 to 5 mm.

[0065] In the present invention, the electrolysis device includes an ultrasonic auxiliary unit vibration pool 9.

[0066] In the present invention, the electrolysis device includes an ultrasonic auxiliary unit system power supply 7 connected to the ultrasonic auxiliary unit vibration pool 9, and the electrolytic cell 4 is located in the ultrasonic auxiliary unit vibration pool 9.

[0067] In the present invention, the electrolysis device includes a low-temperature circulation system 8; the ultrasonic auxiliary unit vibration pool 9 is located in the low-temperature circulation system 8. The low-temperature circulation system 8 preferably uses a semiconductor refrigeration chip as a cold source and also includes a PID temperature controller and a thermocouple sensor, with a temperature control accuracy of +1°C.

[0068] The following describes in detail a method and apparatus for preparing high-purity indium powder by utilizing pulse electrolysis-ultrasound synergy provided by the present invention in conjunction with the embodiments. However, these embodiments should not be construed as limiting the scope of protection of the present invention.

[0069] The schematic diagram of the electrolysis device used in the embodiment is as follows Figure 1 As shown: pulse power supply 1; cathode plate 2; anode plate 3; electrolytic cell 4; vibrating mesh interlayer plate 5; vibrating mesh interlayer plate 6; ultrasonic auxiliary unit system power supply 7; low-temperature circulation system 8; ultrasonic auxiliary unit vibration cell 9; four groups of high-purity indium anode plates are connected into one group and connected to the positive pole of the positive and negative adjustable power supply, five titanium cathode plates are connected into one group and connected to the negative pole of the positive and negative adjustable power supply, and the cathode plate is connected to the middle of the electrolytic cell and the vibrating mesh interlayer plate 5.

[0070] In the embodiment of the present application, the electrolyte is prepared by pure water, analytical grade concentrated sulfuric acid, 4N5 metallic indium, analytical grade sodium chloride and additives.

[0071] Example 1

[0072] A method for preparing highly dispersed indium powder by utilizing pulse electrolysis-ultrasound synergy, wherein the preparation method is carried out in the following steps:

[0073] S1. Prepare electrolyte: The pH value of the electrolyte is 2.5, and the components are: 60 g / L indium sulfate, 80 g / L sodium chloride, and 0.5 g / L polyvinyl pyrrolidone.

[0074] S2. Select a double-layer vibrating mesh interlayer sheet with an aperture of 3 mm, insert the cathode sheet into the slot of the vibrating mesh interlayer sheet, and perform pulse electrolysis in the electrolytic cell under a temperature-controlled ultrasonic machine to obtain electrolytic indium.

[0075] The electrolyte was placed in the electrolytic cell, and then the low-temperature circulation system was started, followed by the ultrasonic auxiliary unit system and the pulse power module (the cathode material of the pulse electrolysis was a titanium plate, the anode material was a rotary cast high-purity indium plate with a purity of 99.995%, and the distance between adjacent cathodes and anodes was 5 cm; the pulse parameters were a pulse current density of 100 A / m 2 , pulse width 6ms, duty cycle 50%; in the ultrasonic-assisted system, the electrolyte temperature is maintained at 25°C and the power is 60kHz to promote particle exfoliation and self-assembly); under the synergistic effect of multiple modules, within each 30-minute operating cycle, the low-temperature circulation system is shut down from the 25th minute to the 30th minute to avoid local overheating and utilize, while the ultrasonic-assisted unit system maintains constant power, the pulse power module switches to low-power mode, and the output waveform of the pulse power module in the low-power mode is switched to continuous micro-pulses, and the micro-pulse frequency is an integer multiple of the resonant frequency of the ultrasonic-assisted unit system to refine the grains;

[0076] S3. After completion, the electrolysis products are collected from the bottom of the electrolytic cell and the cathode plate, washed with pure water, and vacuum dried.

[0077] After washing with pure water, vacuum drying was performed using a step-by-step temperature ramp: 40°C / 2h → 80°C / 3h → 120°C / 1h, with a vacuum degree ≤ 10 Pa. After drying, particle size, purity, and surface analysis were performed.

[0078] Example 2

[0079] A method for preparing highly dispersed indium powder by utilizing pulse electrolysis-ultrasound synergy, wherein the preparation method is carried out in the following steps:

[0080] S1. Prepare electrolyte: The electrolyte has a pH value of 3.5 and contains 80 g / L indium sulfate, 100 g / L potassium chloride, 0.5 g / L polyvinyl pyrrolidone, and 0.3 g / L gelatin.

[0081] S2. Select a double-layer vibrating mesh interlayer sheet with an aperture of 5 mm, insert the cathode sheet into the slot of the vibrating mesh interlayer sheet, and perform pulse electrolysis in the electrolytic cell under a temperature-controlled ultrasonic machine to obtain electrolytic indium.

[0082] The electrolyte is placed in the electrolytic cell, and then the low-temperature circulation system is started, followed by the ultrasonic auxiliary unit system and the pulse power module (the cathode material of the pulse electrolysis is a titanium plate, the anode material is a rotary cast high-purity indium plate with a purity of 99.995%, and the electrode spacing is 6 cm; the pulse parameters are a pulse current density of 180A / m 2 , pulse width 4ms, duty cycle 30%; in the ultrasonic-assisted system, the electrolyte temperature is maintained at 20°C and the power is 80kHz to promote particle exfoliation and self-assembly); under the synergistic effect of multiple modules, within each 30-minute operating cycle, the low-temperature circulation system is shut down from the 25th minute to the 30th minute to avoid local overheating and utilize, while the ultrasonic-assisted unit system maintains constant power, the pulse power module switches to low-power mode, and the output waveform of the pulse power module in the low-power mode is switched to continuous micro-pulses, and the micro-pulse frequency is an integer multiple of the resonant frequency of the ultrasonic-assisted unit system to refine the grains;

[0083] S3. After completion, the electrolysis products are collected from the bottom of the electrolytic cell and the cathode plate, washed with pure water, and vacuum dried.

[0084] After washing with pure water, a step-by-step heating program was used: 40°C / 1h → 80°C / 2h → 120°C / 1h, with a vacuum degree of ≤10 Pa. After drying, purity and surface analysis were performed.

[0085] In this embodiment, the aperture of the double-layer vibrating mesh spacer is 5 mm, and the distance between the cathode and the anode is 6 cm.

[0086] Example 3

[0087] A method for preparing highly dispersed indium powder by utilizing pulse electrolysis-ultrasound synergy, wherein the preparation method is carried out in the following steps:

[0088] S1. Prepare electrolyte: The electrolyte has a pH value of 3.0 and contains 80 g / L indium sulfate, 80 g / L sodium chloride, 0.5 g / L polyvinyl pyrrolidone, 0.3 g / L gelatin, and 0.3 g / L polyacrylic acid.

[0089] S2. Select a double-layer vibrating mesh interlayer sheet with an aperture of 2 mm, insert the cathode sheet into the slot of the vibrating mesh interlayer sheet, and perform pulse electrolysis in the electrolytic cell under a temperature-controlled ultrasonic machine to obtain electrolytic indium.

[0090] The electrolyte is placed in the electrolytic cell, and then the low-temperature circulation system is started, followed by the ultrasonic auxiliary unit system and the pulse power module (the cathode material of the pulse electrolysis is a titanium plate, the anode material is a rotary cast high-purity indium plate with a purity of 99.995%, and the electrode spacing is 4 cm; the pulse parameters are a pulse current density of 250A / m 2 , pulse width 5ms, duty cycle 50%; in the ultrasonic-assisted system, the electrolyte temperature is maintained at 20°C and the power is 65kHz to promote particle exfoliation and self-assembly); under the synergistic effect of multiple modules, within each 30-minute operating cycle, the low-temperature circulation system is shut down from the 25th minute to the 30th minute to avoid local overheating and utilize, while the ultrasonic-assisted unit system maintains constant power, the pulse power module switches to low-power mode, and the output waveform of the pulse power module in the low-power mode is switched to continuous micro-pulses, and the micro-pulse frequency is an integer multiple of the resonant frequency of the ultrasonic-assisted unit system to refine the grains;

[0091] S3. After completion, the electrolysis products are collected from the bottom of the electrolytic cell and the cathode plate, washed with pure water, and vacuum dried.

[0092] After washing with pure water, a step-by-step heating program was used: 40°C / 1h → 80°C / 3h → 120°C / 0.5h, with a vacuum degree of ≤10 Pa. After drying, purity and surface analysis were performed.

[0093] The double-layer vibrating mesh spacer of the device in this embodiment has an aperture of 2 mm, and the distance between the cathode and the anode is 4 cm.

[0094] Figure 2 This is the indium powder prepared in Example 3.

[0095] Example 4

[0096] A method for preparing highly dispersed indium powder by utilizing pulse electrolysis-ultrasound synergy, wherein the preparation method is carried out in the following steps:

[0097] S1. Prepare electrolyte: The pH value of the electrolyte is 2.5, and the components are: 35 g / L indium nitrate, 80 g / L sodium chloride, 1 g / L gelatin, and 0.3 g / L polyacrylic acid.

[0098] S2. Select a double-layer vibrating mesh interlayer sheet with an aperture of 3 mm, insert the cathode sheet into the slot of the vibrating mesh interlayer sheet, and perform pulse electrolysis in the electrolytic cell under a temperature-controlled ultrasonic machine to obtain electrolytic indium.

[0099] The electrolyte was placed in the electrolytic cell, and then the low-temperature circulation system was started, followed by the ultrasonic auxiliary unit system and the pulse power module (the cathode material of the pulse electrolysis was a titanium plate, the anode material was a rotary cast high-purity indium plate with a purity of 99.995%, and the distance between adjacent cathodes and anodes was 6 cm; the pulse parameters were a pulse current density of 150 A / m2 , pulse width 4ms, duty cycle 30%; in the ultrasonic-assisted system, the electrolyte temperature is maintained at 25°C and the power is 80kHz to promote particle exfoliation and self-assembly); under the synergistic effect of multiple modules, within each 30-minute operating cycle, the low-temperature circulation system is shut down from the 25th minute to the 30th minute to avoid local overheating and utilize, while the ultrasonic-assisted unit system maintains constant power, the pulse power module switches to low-power mode, and the output waveform of the pulse power module in the low-power mode is switched to continuous micro-pulses, and the micro-pulse frequency is an integer multiple of the resonant frequency of the ultrasonic-assisted unit system to refine the grains;

[0100] S3. After completion, the electrolysis products are collected from the bottom of the electrolytic cell and the cathode plate, washed with pure water, and vacuum dried.

[0101] After washing with pure water, vacuum drying was performed using a step-by-step temperature ramp: 40°C / 2h → 80°C / 2h → 120°C / 1h, with a vacuum degree ≤ 10 Pa. After drying, particle size, purity, and surface analysis were performed.

[0102] The double-layer vibrating mesh spacer of the device in this embodiment has an aperture of 3 mm, and the distance between the cathode and the anode is 6 cm.

[0103] Example 5

[0104] A method for preparing highly dispersed indium powder by utilizing pulse electrolysis-ultrasound synergy, wherein the preparation method is carried out in the following steps:

[0105] S1. Prepare electrolyte: The electrolyte has a pH value of 2.0 and contains 55 g / L indium nitrate, 80 g / L sodium chloride, 40 g / L potassium chloride, and 0.5 g / L gelatin.

[0106] S2. Select a double-layer vibrating mesh interlayer sheet with an aperture of 5 mm, insert the cathode sheet into the slot of the vibrating mesh interlayer sheet, and perform pulse electrolysis in the electrolytic cell under a temperature-controlled ultrasonic machine to obtain electrolytic indium.

[0107] The electrolyte was placed in the electrolytic cell, and then the low-temperature circulation system was started, followed by the ultrasonic auxiliary unit system and the pulse power module (the cathode material of the pulse electrolysis was a titanium plate, the anode material was a rotary cast high-purity indium plate with a purity of 99.995%, and the distance between adjacent cathodes and anodes was 5 cm; the pulse parameters were a pulse current density of 200 A / m 2, pulse width 6ms, duty cycle 30%; in the ultrasonic-assisted system, the electrolyte temperature is maintained at 25°C and the power is 80kHz to promote particle exfoliation and self-assembly); under the synergistic effect of multiple modules, within each 30-minute operating cycle, the low-temperature circulation system is shut down from the 25th minute to the 30th minute to avoid local overheating and utilize, while the ultrasonic-assisted unit system maintains constant power, the pulse power module switches to low-power mode, and the output waveform of the pulse power module in the low-power mode is switched to continuous micro-pulses, and the micro-pulse frequency is an integer multiple of the resonant frequency of the ultrasonic-assisted unit system to refine the grains;

[0108] S3. After completion, the electrolysis products are collected from the bottom of the electrolytic cell and the cathode plate, washed with pure water, and vacuum dried.

[0109] After washing with pure water, vacuum drying was performed using a step-by-step temperature ramp: 40°C / 1h → 80°C / 1h → 120°C / 1h, with a vacuum degree ≤ 10 Pa. After drying, particle size, purity, and surface analysis were performed.

[0110] The double-layer vibrating mesh spacer of the device in this embodiment has an aperture of 5 mm, and the distance between the cathode and the anode is 5 cm.

[0111] Performance Testing

[0112] 1. Particle size distribution

[0113] The particle size distribution of the high-purity indium powder obtained in Example 1 was tested. The test results are as follows: Figure 3 shown.

[0114] from Figure 3 It can be seen that the particle size of indium powder is mainly concentrated around 35μm.

[0115] 2. Purity testing

[0116] The purity of the high-purity indium powder obtained in Examples 1 to 3 was analyzed, and the analysis results are shown in Table 1:

[0117] Table 1 Purity analysis results of high-purity indium powder obtained in Examples 1 to 5

[0118]

[0119] As can be seen from Table 1, the purity of the high-purity indium powder prepared by the present invention is above 99.9999%, reaching the 6N industry standard.

[0120] The purities of the high-purity indium powders in Examples 1 to 3 of the present invention are 9.99995%, 99.99996%, 99.99998%, 99.99992%, and 99.99993%, respectively.

[0121] 3. SEM analysis

[0122] The high-purity indium powders obtained in Example 1, Example 2, Example 3, Example 4, and Example 5 were subjected to SEM surface analysis. The analysis results are as follows: Figure 4 、 Figure 5 、 Figure 6 、 Figure 7 and Figure 8 shown.

[0123] Depend on Figures 4 to 8 It can be seen that the powder obtained by deposition under the synergistic effect of pulse-ultrasound has a smaller particle size, and the obtained indium powder has a uniform particle size and good dispersibility. Among them, the powder obtained in Example 3 has the best dispersibility.

[0124] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing high-purity indium powder by utilizing pulse electrolysis-ultrasound synergy, characterized in that: The following steps are involved: Under ultrasonic conditions, the electrolyte is subjected to pulse electrolysis to obtain high-purity indium powder; The pH value of the electrolyte is 2.0 to 3.5; The electrolyte comprises the following components: 30-80 g / L of indium salt, 80-120 g / L of chloride salt and 0.5-1.5 g / L of additive.

2. The method according to claim 1, characterized in that The indium salt includes indium sulfate and / or indium nitrate; the chloride salt includes sodium chloride and / or potassium chloride; The additives include one or more of gelatin, β-naphthoic acid, polyvinyl pyrrolidone and polyacrylic acid.

3. The method according to claim 1, characterized in that The current density of the pulse electrolysis is 100-250A / m 2 , the pulse width is 4 to 10 ms, and the duty cycle is 30 to 50%.

4. The method according to claim 1 or 3, characterized in that The temperature of the electrolyte during the pulse electrolysis process is 10-30°C.

5. The method according to claim 1 or 3, characterized in that The frequency of the ultrasound is 20 to 80 kHz.

6. The method according to claim 5, characterized in that During the pulse electrolysis, the direction of the electric field is perpendicular to the vibration direction of the ultrasound.

7. The method according to claim 1, characterized in that After the pulse electrolysis is completed, the method further comprises: performing post-processing on the obtained product to obtain the high-purity indium powder; The post-processing includes: performing solid-liquid separation on the obtained product, and then washing and vacuum drying the obtained solid; The vacuum drying comprises keeping the temperature at 40° C. for 1 to 2 hours, then heating the temperature to 80° C. for 2 to 3 hours, and then heating the temperature to 120° C. for 0.5 to 1 hour. The vacuum degree of the vacuum drying is ≤10Pa.

8. The electrolysis device used in the method according to any one of claims 1 to 7, characterized in that: It comprises a pulse power supply (1), a plurality of cathode plates (2), a plurality of anode plates (3), and an electrolytic cell (4); The plurality of cathode sheets (2) and the plurality of anode sheets (3) are located in the electrolytic cell (4) and are perpendicular to the bottom of the electrolytic cell (4); the plurality of cathode sheets (2) are connected to the negative electrode of the pulse power supply (1); and the plurality of anode sheets (3) are connected to the positive electrode of the pulse power supply (1); and anode sheets are inserted into adjacent cathode sheets among the plurality of cathode sheets (2); It also includes: a multi-layer vibrating mesh spacer sheet located below the plurality of cathode sheets (2) and the plurality of anode sheets (3) and parallel to the bottom of the electrolytic cell (4); the bottoms of the plurality of cathode sheets (2) are embedded in the vibrating mesh spacer sheet adjacent thereto; It also includes: an ultrasonic auxiliary unit vibration pool (9), and an ultrasonic auxiliary unit system power supply (7) connected to the ultrasonic auxiliary unit vibration pool (9); the electrolytic cell (4) is located in the ultrasonic auxiliary unit vibration pool (9); A low-temperature circulation system (8); the ultrasonic auxiliary unit vibration pool (9) is located in the low-temperature circulation system (8).

9. The electrolysis device according to claim 8, characterized in that The material of the plurality of cathode plates (2) is titanium plate, the material of the plurality of anode plates (3) is high-purity indium plate with a purity of ≥99.995%, and the distance between adjacent cathode plates and anode plates is 4 to 6 cm.

10. The electrolysis device according to claim 8, characterized in that The multi-layer vibrating mesh spacer sheet comprises a first vibrating mesh spacer sheet (5) and a second vibrating mesh spacer sheet (6) located between the first vibrating mesh spacer sheet (5) and the electrolytic cell (4); The mesh aperture of each layer of the multi-layer vibration mesh spacer sheet is independently 1 to 5 mm; The low-temperature circulation system (8) uses a semiconductor refrigeration chip as a cold source and also includes a PID temperature controller and a thermocouple sensor, with a temperature control accuracy of +1°C.

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