Dry recovery method for waste indium and gallium targets

Abstract

The invention discloses a dry recovery method for waste indium-gallium targets, which comprises the following steps of: crushing the waste indium-gallium targets to obtain waste target particles; the waste target particles and a carbonaceous reducing agent are mixed and added into a reduction furnace to be subjected to a carbon thermal reduction reaction, liquid indium gallium alloy is obtained, then a sodium hydroxide solution is added to be stirred and precipitated, then solid-liquid separation is conducted, a sodium gallate solution and indium-rich metal are obtained, the indium-rich metal is subjected to electrolytic refining, and high-purity refined indium is obtained; the sodium gallate solution is subjected to acidification, impurity removal and hydrolytic precipitation, and gallium hydroxide powder is obtained. The indium-gallium alloy is directly obtained through the carbon thermal reduction reaction, so that metal loss caused by multi-step leaching, separation, replacement and other processes in a wet process is avoided, and the recovery rate is increased; a large amount of strong acid, strong base and organic extractant are not needed, the auxiliary material consumption is small, the price is low, wastewater discharge is reduced, and the recovery cost is reduced; liquid indium gallium alloy passes through the liquid outlet in the bottom of the reduction furnace, full-continuous or semi-continuous batch production is achieved, and the recovery efficiency is high.

Description

Technical Field

[0001] This invention relates to the field of target waste recycling technology, and in particular to a dry recycling method for indium gallium waste targets. Background Technology

[0002] Indium gallium oxide (IGO) sputtering targets are a key material for preparing transparent conductive thin films and are widely used in high-end electronic fields such as flat panel displays, photovoltaic cells, and semiconductor devices. With the rapid development of related electronic industries, the consumption of IGO sputtering targets continues to increase, leading to a corresponding rise in the amount of waste IGO sputtering targets. Indium and gallium are both rare and precious metals with scarce reserves and high mining costs. Efficiently recovering indium and gallium from waste IGO sputtering targets can not only reduce resource waste but also improve industrial economic efficiency, demonstrating significant value in resource recycling.

[0003] Currently, the main technology for recovering indium and gallium from indium-gallium targets is hydrometallurgy. The core process involves leaching the waste material with chemical reagents such as acids and alkalis, followed by subsequent steps such as precipitation, extraction, and electrolysis to separate and purify indium and gallium.

[0004] However, existing hydrometallurgical technologies often require leaching and subsequent separation and purification processes to be carried out under harsh conditions such as high temperature and high pressure, resulting in high energy consumption and demanding recovery conditions. Hydrometallurgical processes require the use of large amounts of strong acids, strong alkalis, and various extractants and precipitants, which not only increases raw material costs but also generates large amounts of industrial wastewater containing heavy metal ions and chemical reagents. Wastewater treatment is difficult and costly, and can easily cause secondary pollution. To achieve efficient separation of indium and gallium, a sophisticated multi-step extraction, back-extraction, and washing process needs to be designed. This process is lengthy and cumbersome, difficult to operate, and reagent residues or component mixing are prone to occur between steps, leading to a decrease in product purity. Strong acid and strong alkali systems can cause severe corrosion to reaction equipment, requiring the use of expensive corrosion-resistant materials to prepare the equipment, further increasing equipment investment and maintenance costs.

[0005] In addition, existing wet processes are limited by multi-step intermittent leaching and separation processes. Each step requires separate feeding, discharging and subsequent processing, which makes it impossible to achieve continuous feeding and continuous production, resulting in low production efficiency and difficulty in meeting the needs of large-scale industrial production.

[0006] Existing hydrometallurgical recycling technologies suffer from problems such as high energy consumption, high pollution, high cost, complex processes, and inability to achieve continuous recycling, making it difficult to meet the current demands of the resource recycling industry for efficient, environmentally friendly, and economical recycling technologies. Therefore, it is necessary to improve them. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the purpose of this invention is to provide a dry recycling method for indium gallium waste targets, which simplifies the process, reduces energy consumption and costs, reduces environmental pollution, improves recycling efficiency and product purity, and enables continuous and large-scale operation.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is: a dry recycling method for indium gallium waste targets, comprising the following steps:

[0009] S1, Waste target pretreatment step, crushing the indium gallium waste target to obtain waste target particles;

[0010] S2, carbothermic reduction smelting step, the waste target particles are mixed with carbonaceous reducing agent and added to the reduction furnace, the furnace charge is heated to the target temperature of 700~1500℃ to carry out carbothermic reduction reaction, and liquid indium gallium alloy is obtained.

[0011] The reduction furnace includes a medium-frequency induction furnace, a graphite crucible installed inside the medium-frequency induction furnace, and a medium-frequency furnace control cabinet electrically connected to the medium-frequency induction furnace. An induction coil is installed around the graphite crucible in the medium-frequency induction furnace, and the medium-frequency furnace control cabinet is electrically connected to the induction coil. A drain port is installed at the bottom of the graphite crucible.

[0012] S3, the separation and refining step, includes the following sub-steps:

[0013] S3.1, Indium gallium separation sub-step: Liquid indium gallium alloy is discharged from the drain port into the reactor. Sodium hydroxide solution is added to the reactor and stirred. After precipitation, solid-liquid separation is performed to obtain sodium gallate solution and indium-rich metal.

[0014] S3.2, Indium recovery step, indium-rich metal is electrolytically refined to obtain high-purity indium;

[0015] S3.3, Gallium recovery step, acidifying and removing impurities from sodium gallate solution, followed by hydrolysis and precipitation to obtain gallium hydroxide powder.

[0016] In a further technical solution, step S2 includes the following sub-steps:

[0017] S2.1, Feeding sub-step: The waste target particles and carbonaceous reducing agent are continuously or in batches added to the reduction furnace.

[0018] S2.2, the melting sub-step, involves heating the furnace charge to a target temperature of 700~1500℃ to carry out a carbothermic reduction reaction to obtain liquid indium gallium alloy;

[0019] S2.3, Alloy forming sub-step: Liquid indium gallium alloy is discharged from the drain port into a preheated mold for casting. The mold is set below the drain port. After cooling, an indium gallium alloy ingot is obtained.

[0020] In step S3.1, the indium gallium alloy ingot is melted in a resistance heating furnace, and then added to the reaction vessel after the indium gallium alloy ingot has melted.

[0021] In a further technical solution, the ratio of the total molar amount of carbon in the carbonaceous reducing agent to the total molar amount of carbon required for the complete reduction of indium oxide and gallium oxide in the indium gallium waste target to metal is 1.05:1 to 1.30:1.

[0022] In a further technical solution, in step S2, the carbonaceous reducing agent is charcoal.

[0023] In a further technical solution, the reaction time for the carbothermic reduction reaction in step S2 is 1 to 8 hours.

[0024] In a further technical solution, the reduction furnace is also equipped with an atmosphere control device, which is connected to the medium-frequency induction furnace. In step S2, the medium-frequency induction furnace is evacuated or filled with a protective atmosphere through the atmosphere control device.

[0025] In a further technical solution, in step S1, the indium gallium waste target is cleaned and dried before crushing. The dried indium gallium waste target is first put into a jaw crusher and crushed using a corundum jaw plate to obtain waste target particles with a particle size of 1~10mm.

[0026] In a further technical solution, in step S3.1, the mass concentration of the sodium hydroxide solution is 15-30%, the mass ratio of the amount of sodium hydroxide solution added to the indium gallium alloy ingot is 2:1-4:1, the stirring time is 1-6 hours, and the precipitation time is 0.5-3 hours.

[0027] In a further technical solution, in step S3.2, a stainless steel plate or titanium plate is placed in an electrolytic cell, an acidic electrolyte is injected into the electrolytic cell, an indium-rich metal is immersed in the acidic electrolyte, the indium-rich metal is electrically connected to the positive electrode of the power supply, and the stainless steel plate or titanium plate is electrically connected to the negative electrode of the power supply. The power supply voltage is set to 0.2~2V, and electrolysis is performed for 168~192 hours. Indium is deposited on the surface of the stainless steel plate or titanium plate, and after peeling, washing and drying, high-purity refined indium is obtained.

[0028] In a further technical solution, in step S3.3, the sodium gallate solution is washed multiple times with hot water at 60~90℃, and then acid is slowly added to the washed sodium gallate solution to adjust the pH value to 2~4, so that the sodium gallate is converted into gallium ions to obtain a gallium ion solution.

[0029] Add a complexing agent or a sulfiding agent to the gallium ion solution and stir. After precipitation, separate the solid and liquid phases, filter the precipitate, and obtain a purified gallium ion solution.

[0030] An alkaline solution is added to the purified gallium ion solution to adjust the pH value of the purified gallium ion solution to neutral or weakly alkaline. After stirring, the precipitate is precipitated, and then filtered, washed and dried to obtain gallium hydroxide powder.

[0031] In the optional technical solution, step S2 adopts a continuous production method with batch feeding, including the following steps:

[0032] Perform step S1, the waste target pretreatment step.

[0033] In step S2, the carbothermic reduction smelting step, waste target particles are mixed with carbonaceous reducing agent and added to the reduction furnace in batches. Each batch of furnace charge is heated to a target temperature of 700~1500℃ for carbothermic reduction reaction for 1~8 hours to obtain liquid indium gallium alloy.

[0034] Perform step S3 to separate and refine the product.

[0035] In the optional technical solution, step S2 adopts a continuous production method with continuous material feeding, including the following steps:

[0036] Perform step S1, the waste target pretreatment step.

[0037] In step S2, the carbothermic reduction smelting step, waste target particles are mixed with carbonaceous reducing agent and continuously added to the reduction furnace. The furnace charge is heated to a target temperature of 700~1500℃ to carry out the carbothermic reduction reaction and obtain liquid indium gallium alloy. The time from feeding to discharging is 1~8 hours.

[0038] Perform step S3 to separate and refine the product.

[0039] The advantages of this invention compared to existing technologies are: by directly obtaining indium gallium alloy ingots through carbothermal reduction reaction, metal loss caused by multiple steps of leaching, separation, and displacement in wet processes is avoided, thus improving the recovery rate.

[0040] The dry process of crushing and then casting indium gallium alloy ingots via carbothermal reduction simplifies subsequent separation and refining steps, shortens the overall recycling process, reduces equipment investment and floor space requirements, and significantly improves production efficiency and shortens the production cycle.

[0041] Dry recycling eliminates the need for large amounts of strong acids, strong alkalis, and organic extractants. Only small amounts of acid and alkali are used during separation and refining, resulting in less acidic or alkaline wastewater and no heavy metal sludge or toxic organic wastewater. This avoids secondary pollution and improves environmental friendliness. The reaction tail gas is mainly carbon monoxide, which can be easily treated into carbon dioxide through combustion. Waste gas treatment is simple and low-cost.

[0042] Using widely available and inexpensive carbon as the sole reducing agent, replacing expensive acid and alkali reagents, and employing medium-frequency induction heating, heat is generated directly inside the furnace charge, resulting in high thermal efficiency, rapid heating, low temperature loss rate under continuous production, and low overall energy consumption. The main body of the reduction furnace is conventional metallurgical equipment, eliminating the need for expensive materials resistant to strong acid corrosion, thus reducing investment and maintenance costs.

[0043] Stable indium gallium alloys are obtained directly through carbothermal reduction reaction. After casting and cooling, indium gallium alloy ingots are obtained, which can be used as high-value intermediate products for easy storage and trading. At the same time, indium gallium alloy ingots can be separated and purified through mature alkali treatment and electrolysis processes to obtain high-purity refined indium with a purity of ≥99.995% and gallium hydroxide with a purity of ≥99.6%, respectively. The products can directly meet the needs of high-end application markets.

[0044] Continuous production is possible through the drain port at the bottom of the reduction furnace, enabling fully continuous or semi-continuous batch production. It is suitable for large-scale production and has high recovery efficiency. Attached Figure Description

[0045] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0046] Figure 1 This is a flowchart of Embodiment 1 of the present invention;

[0047] Figure 2 This is a flowchart of Embodiment 2 of the present invention;

[0048] Figure 3 This is a comparison table of consumption between Embodiment 2 and Comparative Example 2 of the present invention. Detailed Implementation

[0049] The following are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention.

[0050] Example 1

[0051] A dry recycling method for indium gallium waste targets, such as Figure 1 As shown, it includes the following steps:

[0052] S1, Waste target pretreatment step

[0053] After cleaning and drying, the indium-gallium (IGa) waste targets, containing 70.3% indium and 11.16% gallium by mass, are first placed in a jaw crusher and crushed using corundum jaw plates to obtain waste target particles with a diameter of 1-10 mm. Crushing the IGa targets increases the specific surface area of ​​the reactants, improving mass and heat transfer efficiency in the subsequent carbothermic reduction smelting step, ensuring a rapid and uniform carbothermic reduction reaction.

[0054] S2, the carbothermic reduction smelting step, includes the following sub-steps.

[0055] S2.1, the feeding sub-step involves adding the waste target particles and carbonaceous reducing agent to the reduction furnace in batches. The ratio of the total molar amount of carbon in the carbonaceous reducing agent to the total molar amount of carbon required for the complete reduction of indium oxide and gallium oxide in the indium-gallium waste target to metal is 1.05:1 to 1.30:1. In this embodiment, charcoal is used as the carbon reducing agent because it is inexpensive and can reduce recycling costs. In this embodiment, the feeding sub-step adopts a continuous production method of batch feeding, where 10 kg of waste target particles are mixed with 1.5 kg of charcoal and added to the reduction furnace. Of course, a continuous production method of continuous feeding can also be used, with the time from feeding to discharge being 1 to 8 hours, and the feeding port of the reduction furnace being the cooling end.

[0056] S2.2, Melting Sub-step: The power of the reduction furnace is set to 30~40KW. The furnace charge is heated to the target temperature of 800~1200℃ for carbothermic reduction reaction for 4 hours. During the carbothermic reduction reaction, the carbon reducing agent "steals" oxygen from indium and gallium oxides, generating gaseous carbon monoxide (CO) which is discharged from the reaction system. Metallic indium and gallium are reduced, and indium oxide is released. The chemical reaction formula is Gallium oxide The chemical reaction formula is Because the reaction temperature is much higher than the melting points of indium and gallium (indium 156.6℃, gallium 29.8℃), the reduced metal immediately melts into a liquid state, thus obtaining a liquid indium-gallium alloy.

[0057] The reduction furnace includes a medium-frequency induction furnace, a graphite crucible installed inside the medium-frequency induction furnace, and a medium-frequency furnace control cabinet electrically connected to the medium-frequency induction furnace. An induction coil is installed around the graphite crucible in the medium-frequency induction furnace, and the medium-frequency furnace control cabinet is electrically connected to the induction coil. A drain port is installed at the bottom of the graphite crucible.

[0058] The high-density liquid indium gallium alloy collects at the bottom of the graphite crucible under the influence of gravity. The drain port is equipped with a sealing door made of high-temperature resistant material. By opening the sealing door, the liquid indium gallium alloy in the graphite crucible can be discharged, realizing continuous or intermittent discharge, which facilitates continuous and large-scale recycling production.

[0059] The medium-frequency furnace control cabinet is used to convert the power frequency AC power from the grid into DC power through rectification, and then into medium-frequency AC power that can resonate with the induction coil through an inverter whose frequency is determined by an LC oscillation circuit. Finally, through the control system, the power of the reduction furnace is precisely adjusted and protected.

[0060] When an intermediate frequency alternating current is applied to the induction coil, an alternating magnetic field is generated. This magnetic field causes eddy currents to be generated inside the furnace material (especially conductive metal materials) in the graphite crucible. The eddy currents overcome the resistance and do work to generate heat (i.e., eddy current heating effect), thus achieving rapid heating of the material.

[0061] Preferably, the reduction furnace is also equipped with an atmosphere control device, which is connected to the medium-frequency induction furnace. During the carbothermic reduction smelting step, the atmosphere control device uses a vacuum pump or a gas-charging pump to evacuate or charge the medium-frequency induction furnace with a protective atmosphere. During the carbothermic reduction reaction ( The carbothermal reduction process itself generates a large amount of carbon monoxide (CO), a strong reducing gas. In a confined space, this self-generated carbon monoxide displaces air, naturally creating a localized reducing atmosphere. Therefore, it is not always necessary to fill with a protective atmosphere or evacuate. However, at high temperatures, the reduced liquid indium and gallium are highly reactive. If the airtightness of the reduction furnace decreases, oxygen from the outside air will seep in, causing oxidation and forming slag, reducing the direct metal recovery rate and product purity. Therefore, actively evacuating or filling with a protective atmosphere ensures that the carbothermal reduction reaction process is always in a strongly reducing or inert environment, eliminating uncertainty, improving reliability and stability, ensuring consistency between batches in continuous production, and increasing the recovery rate. Furthermore, carbon monoxide is a flammable, explosive, and toxic gas. Operating under a protective atmosphere allows for better control and collection of exhaust gases (such as extracting and burning CO), preventing accumulation or leakage within the reduction furnace, thus improving safety and environmental friendliness.

[0062] S3, the separation and refining step, includes the following sub-steps:

[0063] S3.1, Indium-gallium separation sub-step: Liquid indium-gallium alloy is discharged from the drain port into the reactor. A sodium hydroxide solution with a mass concentration of 15~30% is added to the reactor and heated and stirred for 3 hours. After precipitation for 1 hour, solid-liquid separation is performed to obtain sodium gallate solution and indium-rich metal.

[0064] S3.2, Indium recovery step: Place a stainless steel plate or titanium plate into an electrolytic cell, inject an acidic electrolyte (indium sulfate solution) into the electrolytic cell, immerse indium-rich metal in the indium sulfate solution, electrically connect the indium-rich metal to the positive terminal of the power supply, and electrically connect the stainless steel plate or titanium plate to the negative terminal of the power supply. Set the power supply voltage to 1V, electrolyze for 168~192 hours, with the stainless steel plate or titanium plate as the cathode and the indium-rich metal as the anode. After the electrolysis reaction is completed, indium is deposited on the surface of the stainless steel plate or titanium plate, and after peeling, washing and drying, high-purity refined indium with a purity ≥99.995% is obtained.

[0065] S3.3, Gallium ion recovery step: The sodium gallate solution is washed multiple times with hot water at 60~90℃ to remove excess alkali (sodium hydroxide). Then, acid (hydrochloric acid or sulfuric acid) is slowly added to the washed sodium gallate solution to adjust the pH value to 3~4, so that the sodium gallate in the sodium gallate solution is converted into gallium ions, and a gallium ion solution is obtained, thus completing the acidification.

[0066] Add a sulfiding agent (sodium sulfide) to the gallium ion solution and stir. After precipitation, the solid and liquid are separated. After filtering the precipitate, a purified gallium ion solution is obtained. The precipitate is usually a common metal impurity such as aluminum, zinc, and copper, thus completing the impurity removal.

[0067] Add alkaline solution to the purified gallium ion solution to adjust the pH value of the purified gallium ion solution to neutral or weakly alkaline (pH value of 6~8), stir and precipitate, then filter, wash and dry the precipitate to obtain gallium hydroxide powder with a purity of ≥99.6%.

[0068] Example 2

[0069] This embodiment is basically the same as Embodiment 1, except that the following steps are added between step S2 and step S3, such as... Figure 2 As shown,

[0070] In step S2.3, the alloy forming sub-step, the high-temperature liquid indium gallium alloy discharged from the drain port flows into a preheated mold or continuous casting machine, and after cooling, yields an 8.02 kg indium gallium alloy ingot. The indium gallium alloy ingot, as an intermediate product, is easy to store and transport, and provides a stable raw material for subsequent refining and separation. Compared to Example 1, directly discharging the high-temperature liquid indium gallium alloy into the reactor can easily cause splashing. However, by first casting the high-temperature liquid indium gallium alloy into an indium gallium alloy ingot through the alloy forming sub-step, and then adding it to the reactor to perform step S3, safety is improved.

[0071] Furthermore, after obtaining the indium-gallium alloy ingot, ICP testing can be performed on the indium-gallium alloy ingot to facilitate sampling and testing of the indium and gallium content. ICP testing of the indium-gallium alloy ingot revealed that indium accounted for 86% of the mass and gallium accounted for 14% of the mass; therefore, the recovery rate of indium oxide was (8.02*86%) / 70.3%=98.11%, and the recovery rate of gallium oxide was (8.02*14%) / 11.16%=96.79%.

[0072] When it is necessary to separate indium and gallium, a separation and refining step is performed. In step S3.1, the indium-gallium alloy ingot is melted in a resistance heating furnace. After the indium-gallium alloy ingot is melted, it is added to the reaction vessel. A sodium hydroxide solution with a mass concentration of 15-30% is added to the reaction vessel and heated and stirred for 3 hours. After precipitation for 1 hour, solid-liquid separation is performed to obtain sodium gallate solution and indium-rich metal. The subsequent steps are the same as in Example 1.

[0073] Depending on production needs, the liquid indium gallium alloy obtained from the carbothermic reduction smelting step can be directly subjected to subsequent separation steps as in Example 1 to achieve fully continuous production, thereby improving production efficiency and enabling large-scale production. Alternatively, as in Example 2, it can be first cast into indium gallium alloy ingots, stored or sold as intermediate products, and then remelted for separation and refining when needed to achieve semi-continuous production, which facilitates storage and trading and improves flexibility.

[0074] Comparative Example 1

[0075] After cleaning and drying, the waste indium-gallium (IGa) targets contained 70.3% indium and 11.16% gallium by mass. The dried targets were first crushed in a jaw crusher using corundum jaw plates, and then ground in a ball mill to obtain target powder. Using an acid leaching method, 10 kg of the powder was added to 30 L of hydrochloric acid, heated to 55-70 °C, stirred for 4 hours, and filtered to obtain 28 L of IGa mixed solution. ICP analysis of this solution showed an indium concentration of 212 g / L and a gallium concentration of 180 g / L. Therefore, the recovery rate of indium was (212 * 0.028) / 70.3% = 84.45%, and the recovery rate of gallium was (180 * 0.028) / 11.16% = 45.16%.

[0076] In Example 2, the carbothermic reduction melting step for extracting indium gallium alloy from indium gallium waste targets is compared with the step for extracting indium gallium mixed solution from indium gallium waste targets in Comparative Example 1, such as... Figure 3As shown, when processing 10 kg of indium gallium waste target, the auxiliary material in Example 2 was 1.5 kg of charcoal, while the auxiliary material in Comparative Example 1 was 30 L of hydrochloric acid; the reaction temperature in Example 2 was 800~1200℃, and the reaction temperature in Comparative Example 1 was 55~70℃; the reaction time for both Example 2 and Comparative Example 1 was 4 hours; the wastewater generated in Example 2 was zero, while the wastewater generated in Comparative Example 1 was 28 L; according to the formula: relative energy consumption index = unit product energy consumption / baseline process energy consumption, under the same baseline process energy consumption, the relative energy consumption index of Example 2 was calculated to be 4000, and the relative energy consumption index of Comparative Example 1 was 250. The comparison shows that the auxiliary materials used in Example 2 are less expensive and lower in cost compared to Comparative Example 1. Furthermore, hydrochloric acid is corrosive, requiring corrosion-resistant equipment, which increases equipment costs. Although Example 2 requires a higher temperature reaction, the energy consumption is a highly efficient one-time process, with subsequent separation and refining requiring only relatively low energy. While Comparative Example 1 had lower energy consumption in extracting the indium-gallium mixture from the indium-gallium waste target, and no further refining was performed on the indium-gallium mixture in this example, the subsequent solution heating, constant-temperature stirring, multi-stage extraction and back-extraction, the high energy consumption of electrolytic purification, and the enormous energy consumed in treating wastewater several times or even tens of times the volume of the product all involve hidden, continuous low-voltage electricity. The total energy consumption of the entire process in Example 2 far exceeds that of Example 2. Within the same 4-hour reaction time, Example 2 directly yields 8.02 kg of high-value indium gallium alloy ingots, which are solid products and easy to handle. In contrast, Comparative Example 1 yields 28 L of low-concentration mixed salt solution, which is still a semi-finished product and requires a long and complex subsequent process to obtain the metal. The product value is low and the production cycle is long. Example 2 has zero wastewater discharge, while Comparative Example 1 generates 28 L of wastewater, which requires subsequent treatment, polluting the environment and increasing wastewater treatment costs and time. Example 2 can carry out continuous production, while Comparative Example 1 can only operate intermittently and cannot achieve continuous production, making it difficult to carry out large-scale processing.

Claims

1. A dry method for recovering indium gallium waste targets, characterized by: Includes the following steps, S1, Waste target pretreatment step, crushing the indium gallium waste target to obtain waste target particles; S2, carbothermic reduction smelting step, the waste target particles are mixed with carbonaceous reducing agent and added to the reduction furnace, the furnace charge is heated to the target temperature of 700~1500℃ to carry out carbothermic reduction reaction, and liquid indium gallium alloy is obtained. The reduction furnace includes a medium-frequency induction furnace, a graphite crucible installed inside the medium-frequency induction furnace, and a medium-frequency furnace control cabinet electrically connected to the medium-frequency induction furnace. An induction coil is installed around the graphite crucible in the medium-frequency induction furnace, and the medium-frequency furnace control cabinet is electrically connected to the induction coil. A drain port is installed at the bottom of the graphite crucible. S3, the separation and refining step, includes the following sub-steps: S3.1, Indium gallium separation sub-step: Liquid indium gallium alloy is discharged from the drain port into the reactor. Sodium hydroxide solution is added to the reactor and stirred. After precipitation, solid-liquid separation is performed to obtain sodium gallate solution and indium-rich metal. S3.2, Indium recovery step, indium-rich metal is electrolytically refined to obtain high-purity indium; S3.3, Gallium recovery step, acidifying and removing impurities from sodium gallate solution, followed by hydrolysis and precipitation to obtain gallium hydroxide powder.

2. The method according to claim 1, wherein: Step S2 includes the following sub-steps. S2.1, Feeding sub-step: The waste target particles and the carbonaceous reducing agent are continuously or in batches added to the reduction furnace, respectively; S2.2, Melting sub-step: The furnace charge is heated to a target temperature of 700~1500℃ to carry out a carbothermic reduction reaction to obtain the liquid indium gallium alloy; S2.3, Alloy forming sub-step: Liquid indium gallium alloy is discharged from the drain port into a preheated mold for casting. The mold is set below the drain port. After cooling, an indium gallium alloy ingot is obtained. In step S3.1, the indium gallium alloy ingot is melted in a resistance heating furnace, and then added to the reaction vessel after the indium gallium alloy ingot has melted.

3. The method of claim 2, wherein the method is characterized by: The ratio of the total molar amount of carbon in the carbonaceous reducing agent to the total molar amount of carbon required for the complete reduction of indium oxide and gallium oxide in the indium gallium waste target to metal is 1.05:1 to 1.30:

1.

4. The method of claim 1, wherein the method is characterized by: In step S2, the carbonaceous reducing agent is charcoal.

5. The method of claim 1, wherein the method is characterized by: In step S2, the reaction time of the carbothermic reduction reaction is 1 to 8 hours.

6. The method of claim 1, wherein the method is characterized by: The reduction furnace is also equipped with an atmosphere control device, which is connected to the medium-frequency induction furnace. In step S2, the medium-frequency induction furnace is evacuated or filled with a protective atmosphere through the atmosphere control device.

7. The method of claim 1, wherein the method is characterized by: In step S1, the indium gallium waste target is cleaned and dried before crushing. The dried indium gallium waste target is first put into a jaw crusher and crushed using a corundum jaw plate to obtain the waste target particles with a particle size of 1~10mm.

8. The method of claim 1, wherein the method is characterized by: In step S3.1, the mass concentration of the sodium hydroxide solution is 15-30%, the mass ratio of the added sodium hydroxide solution to the indium gallium alloy ingot is 2:1-4:1, the stirring time is 1-6 hours, and the precipitation time is 0.5-3 hours.

9. The method of claim 1, wherein the method is characterized by: In step S3.2, a stainless steel plate or titanium plate is placed in an electrolytic cell, and an acidic electrolyte is injected into the electrolytic cell. The indium-rich metal is immersed in the acidic electrolyte, and the indium-rich metal is electrically connected to the positive electrode of the power supply. The stainless steel plate or titanium plate is electrically connected to the negative electrode of the power supply. The power supply voltage is set to 0.2~2V, and electrolysis is performed for 168~192 hours. Indium is deposited on the surface of the stainless steel plate or titanium plate, and after peeling, washing and drying, the high-purity refined indium is obtained.

10. A dry recycling method for indium gallium waste targets according to claim 1, characterized in that: In step S3.3, the sodium gallate solution is washed multiple times with hot water at 60~90℃, and then acid is slowly added to the washed sodium gallate solution to adjust the pH value to 2~4, so that sodium gallate is converted into gallium ions to obtain a gallium ion solution. Add a complexing agent or a sulfiding agent to the gallium ion solution and stir. After precipitation, separate the solid and liquid phases, filter the precipitate, and obtain a purified gallium ion solution. An alkaline solution is added to the purified gallium ion solution to adjust the pH value of the purified gallium ion solution to neutral or weakly alkaline. After stirring, the precipitate is formed, and then the precipitate is filtered, washed, and dried to obtain the gallium hydroxide powder.

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