A method for efficiently recovering high-purity indium from indium phosphide waste

Abstract

The invention discloses a method for efficiently recovering high-purity indium from indium phosphide waste, belonging to the technical field of non-ferrous metal metallurgy. The method of the invention is scientifically and reasonably designed. Firstly, the indium phosphide waste is subjected to sulfation roasting to break the stable covalent bond between indium and phosphorus, so that the insoluble indium phosphide is converted into indium sulfate soluble in water, and at the same time, phosphorus is recovered in the form of phosphorus pentoxide in the gas-phase condensation zone; further, the calcine is subjected to water leaching to enable indium to enter the solution in the form of ions, forming a leaching solution mainly composed of In2(SO4)3-H2SO4; the leaching solution is directly electrolyzed, and by accurately controlling the electrochemical conditions, indium is reduced and precipitated at the cathode, while avoiding the precipitation of impurity ions, and a high-purity indium product is obtained. The technical scheme of the invention has the characteristics of low equipment requirements, high efficiency, low cost, high recovery rate, high product purity, etc., and can realize the efficient comprehensive recovery of indium phosphide waste.

Description

Technical Field

[0001] The present invention belongs to the technical field of non-ferrous metal metallurgy, and particularly relates to a method for efficiently recycling indium from indium phosphide waste. Background Art

[0002] Indium is located in Group IIIA of the fifth period of the periodic table of elements and has excellent physical and chemical properties such as low melting point, high boiling point, and stable properties. Therefore, indium and its compounds are often used in the production of special alloys, electronic components, indium tin oxide, semiconductors and other materials, and have been widely used in the fields of machinery manufacturing, electronic information, photovoltaic optoelectronics, etc. However, the content of indium in the earth's crust is as low as 50-200 ppb, only about one-sixth of that of gold. Indium does not have an independent ore deposit in nature and often exists in the form of associated ore in heavy metal sulfide ores such as sphalerite and pyrite. The most common one is sphalerite, and its indium content is 1-100 ppm.

[0003] Semiconductor is one of the most important application fields of indium. Indium phosphide (InP) semiconductor materials have the advantages of narrow bandgap, low resistivity and high electron mobility. As lasers and receivers, they can significantly improve the data transmission speed and distance, and have been widely used in the fields of microwave communication and optical fiber communication. However, indium phosphide is brittle and has low hardness, and the waste material ratio is as high as about 70% in the process of producing semiconductor devices with it as the raw material. On the other hand, with the rapid development of the semiconductor industry, the update and iteration of indium phosphide semiconductor devices are accelerating, and a large amount of indium phosphide waste will be generated. Therefore, as an important secondary indium resource, the efficient comprehensive recycling of indium phosphide waste has important economic value and social significance.

[0004] At present, the research on the recycling of indium phosphide waste is relatively limited. After retrieval, the Chinese patent document with the publication number CN114380323A discloses a method for recycling indium in indium phosphide. After mixing indium phosphide powder with iron powder evenly, a solid-phase reaction is carried out at high temperature, and then hydrogen chloride gas is introduced to make indium selectively chlorinated to generate volatile indium chloride, and finally InCl3 is recovered by condensation in the gas phase. The indium chloride recovered by this method has a high purity, but the whole recycling process flow is long, the operation is complex, the requirements for equipment are high, and indium is recovered in the form of indium chloride, and further treatment is required to obtain metal indium products.

[0005] The Chinese patent document with the publication number CN106586988B discloses a method for comprehensively recycling indium and phosphorus from indium phosphide waste. The indium phosphide waste powder is placed in a vacuum tube furnace, and indium phosphide is decomposed into indium and phosphorus vapor under high temperature and vacuum conditions, and then the two are recovered separately. Although this method can realize the short-process comprehensive recycling of indium phosphide waste, the production process needs to be realized under high temperature and vacuum conditions, which not only has high energy consumption, but also requires vacuum smelting equipment with high investment cost, and the production cost is high.

[0006] Chinese patent document with publication number CN106319224B discloses a method for recovering indium from indium phosphide waste. Concentrated hydrochloric acid and sodium chlorate are used as leaching agents to fully dissolve the indium phosphide waste, and then zinc powder is added to the leaching solution for replacement to obtain sponge indium. Although this process can effectively recover metallic indium from indium phosphide waste, the chloride ion leaching system under high acidity conditions not only seriously corrodes the equipment, but also easily volatilizes hydrogen chloride gas to pollute the production environment. In addition, the thermodynamic driving force for replacing indium with zinc powder is limited. The addition of excessive zinc powder will reduce the purity of the sponge indium product, and zinc powder belongs to a controlled reagent that is easy to explode, resulting in a relatively high production safety risk.

[0007] In summary, there is still great room for optimization and improvement in the existing indium phosphide waste recovery process. It is necessary to further develop a comprehensive indium phosphide waste recovery process technology that is simple to operate, has a short process, high efficiency, low cost, and is environmentally friendly to provide guarantee for the sustainable development of the indium industry. Summary of the Invention

[0008] The purpose of the present invention is to overcome the problems of the existing comprehensive indium phosphide waste recovery process, such as long process flow, high equipment requirements, low efficiency, high production cost, and low product purity, and provides a method for efficiently recovering refined indium from indium phosphide waste. The process technology of the present invention has the characteristics of low equipment requirements, high efficiency, low cost, high recovery rate, and high product purity, and can realize the efficient comprehensive recovery of indium phosphide waste.

[0009] To achieve the above technical purpose and reach the above technical effect, the present invention is realized through the following technical solutions:

[0010] A method for efficiently recovering refined indium from indium phosphide waste. First, the indium phosphide waste is subjected to sulfation roasting to break the stable covalent bond between indium and phosphorus, convert the insoluble indium phosphide into indium sulfate that is easily soluble in water, and at the same time recover phosphorus in the form of phosphorus pentoxide in the gas-phase condensation zone. The roasted ore is subjected to water leaching to make indium enter the solution in the form of ions, forming a leaching solution mainly composed of In2(SO4)3-H2SO4. The leaching solution is directly electrolyzed. By accurately controlling the electrochemical conditions, indium is reduced and precipitated at the cathode, while avoiding the precipitation of impurity ions, to obtain a refined indium product.

[0011] Furthermore, in the method for efficiently recovering refined indium from indium phosphide waste as described above, the specific process operation is as follows:

[0012] 1) Mix the indium phosphide waste powder and concentrated sulfuric acid evenly in proportion and place them in a tubular furnace;

[0013] 2) Heat it to a predetermined temperature and keep it at a constant temperature for a period of time. The whole process is carried out in a flowing oxygen or air atmosphere, so that the insoluble indium phosphide is converted into indium sulfate that is easily soluble in water, and at the same time, the volatile phosphorus pentoxide generated enters the condensation zone with the flowing gas to achieve the recovery of phosphorus;

[0014] 3) Leach the calcined ore with water so that indium enters the solution in the form of ions. Filter the slurry to separate the insoluble impurities and obtain a pure leaching solution with the main component of In2(SO4)3-H2SO4;

[0015] 4) Directly electrolyze the leaching solution. By accurately controlling the electrochemical conditions, indium is reduced and precipitated at the cathode;

[0016] 5) Strip the precipitated metallic indium from the cathode surface. After washing with deionized water and drying, obtain refined indium products.

[0017] Furthermore, in the method for efficiently recovering refined indium from indium phosphide waste as described above, in step 1), the indium phosphide waste is pre-ground to less than 300 μm, and the purity of concentrated sulfuric acid is 98%.

[0018] Furthermore, in the method for efficiently recovering refined indium from indium phosphide waste as described above, in step 1), the volume ratio of concentrated sulfuric acid to the mass of indium phosphide waste is 1-5 mL / g.

[0019] Furthermore, in the method for efficiently recovering refined indium from indium phosphide waste as described above, in step 2), the heating temperature is 350-450 °C, the heating rate is 5-20 °C / min, the oxygen or air flow rate is 1-5 L / min, the constant temperature reaction time is 1-8 h, and the temperature for recovering phosphorus pentoxide in the condensation zone is 110-150 °C.

[0020] Furthermore, in the method for efficiently recovering refined indium from indium phosphide waste as described above, in step 3), the water leaching temperature is 25-95 °C, the reaction time is 1-5 h, and the mechanical stirring speed is 200-600 r / min.

[0021] Furthermore, in the method for efficiently recovering refined indium from indium phosphide waste as described above, in step 4), the electrolysis system uses graphite or platinum plate as the anode, and titanium plate, stainless steel plate or platinum plate as the cathode. The current density during the electrolysis process is 20-100 A / m 2 , and the temperature of the electrolyte is 25-80 °C.

[0022] Furthermore, in the method for efficiently recovering refined indium from indium phosphide waste as described above, in step 5), the recovered metallic indium is washed 4-8 times with deionized water and dried at 70-110 °C for 24-96 h to obtain refined indium products.

[0023] The beneficial effects of the present invention are:

[0024] 1. The present invention uses a conventional sulfation roasting process to treat indium phosphide waste. By fully reacting with concentrated sulfuric acid, the stable covalent bond between indium and phosphorus is broken, and the insoluble indium phosphide is converted into indium sulfate that is easily soluble in water, which is beneficial to improving the recovery rate of indium. During the roasting process, phosphorus is recovered in the form of phosphorus pentoxide in the gas phase, and the comprehensive recovery rate of valuable elements in the waste is high. The reaction process does not require harsh reaction conditions such as high pressure and vacuum, and has the advantages of simple equipment, low energy consumption, and high phase conversion rate, which can effectively improve production efficiency and reduce production costs.

[0025] 2. The present invention performs water leaching treatment on the sulfation roasting product, which can fully dissolve the target metal indium and make it enter the solution in ionic form to improve the recovery rate of indium. There is no need to use chemical reagents such as strong acids and strong bases as leaching agents, the reagent consumption is small, and the reaction process does not require atmosphere protection and harsh reaction conditions such as high pressure. The full dissolution of indium can be achieved under normal pressure conditions, and it has the advantages of simple equipment, low energy consumption, and low production cost.

[0026] 3. The main component of the leaching solution obtained by water leaching the sulfation roasting product of the present invention is In2(SO4)3-H2SO4, which is an ideal electrolyte for electrolytic deposition of indium. Direct electrolysis is carried out on the leaching solution. By controlling electrochemical conditions such as current density and cell voltage, indium is reduced and deposited at the cathode, while the cathodic reduction of impurity ions is inhibited. High-purity indium products with a purity of more than 99.99% can be obtained through one-step electrolysis, with a high recovery rate of indium and high product purity.

[0027] Of course, it is not necessary for any product implementing the present invention to achieve all of the above advantages simultaneously. Specific Embodiments

[0028] The present invention discloses a method for efficiently recovering high-purity indium from indium phosphide waste, belonging to the technical field of non-ferrous metal metallurgy. The method for efficiently recovering high-purity indium from indium phosphide waste of the present invention first performs sulfation roasting on the indium phosphide waste to break the stable covalent bond between indium and phosphorus, convert the insoluble indium phosphide into indium sulfate that is easily soluble in water, and simultaneously recover phosphorus in the form of phosphorus pentoxide in the gas-phase condensation zone. Further, water leaching is performed on the roasted ore to make indium enter the solution in ionic form, forming a leaching solution mainly composed of In2(SO4)3-H2SO4. Direct electrolysis is carried out on the leaching solution. By accurately controlling the electrochemical conditions, indium is reduced and deposited at the cathode, while avoiding the precipitation of impurity ions, to obtain high-purity indium products. The technical solution of the present invention has the characteristics of low equipment requirements, high efficiency, low cost, high recovery rate, and high product purity, and can achieve the efficient comprehensive recovery of indium phosphide waste.

[0029] The production process of the present invention specifically includes the following steps:

[0030] 1) Mix the indium phosphide waste powder pre-milled to less than 300 μm evenly with concentrated sulfuric acid with a purity of 98% at a ratio of V H2SO4 / m InP = 1 - 5 mL / g, and place it in a tube furnace.

[0031] 2) Heat it to 350 - 450 °C at a rate of 5 - 20 °C / min and keep it at a constant temperature for 1 - 8 h. The whole process is carried out under a flowing oxygen or air atmosphere, and the gas flow rate is 1 - 5 L / min, so that the insoluble indium phosphide is converted into indium sulfate soluble in water, and the volatile phosphorus pentoxide generated enters the condensation zone at a temperature of 110 - 150 °C with the flowing gas to achieve the recovery of phosphorus.

[0032] 3) Leach the calcined ore under mechanical stirring conditions. The stirring speed is 200 - 600 r / min, the leaching temperature is 25 - 95 °C, and the reaction time is 1 - 5 h, so that indium enters the solution in the form of ions. Further filter the slurry to separate insoluble impurities and obtain a pure leaching solution with the main component of In2(SO4)3 - H2SO4.

[0033] 4) Directly electrolyze the leaching solution. Use graphite or platinum plate as the anode, and titanium plate, stainless steel plate or platinum plate as the cathode. Control the current density to be 20 - 100 A / m 2 , and the temperature of the electrolyte is 25 - 80 °C, so that indium is reduced and precipitated at the cathode.

[0034] 5) Strip the precipitated metallic indium from the cathode surface, wash the recovered metallic indium 4 - 8 times with deionized water, and further dry it at a temperature of 70 - 110 °C for 24 - 96 h to obtain refined indium products.

[0035] The present invention will be further described below in conjunction with specific embodiments.

[0036] Example 1

[0037] A method for efficiently recovering refined indium from indium phosphide waste in this example specifically includes the following steps:

[0038] 1) Mix the indium phosphide waste powder pre-milled to less than 300 μm evenly with concentrated sulfuric acid with a purity of 98% at a ratio of V H2SO4 / m InP = 1 mL / g, and place it in a tube furnace.

[0039] 2) Heat it to 350 °C at a rate of 5 °C / min and keep it at a constant temperature for 8 h. The whole process is carried out under a flowing oxygen atmosphere, and the gas flow rate is 1 L / min, so that the insoluble indium phosphide is converted into indium sulfate soluble in water, and the volatile phosphorus pentoxide generated enters the condensation zone at a temperature of 110 °C with the flowing gas to achieve the recovery of phosphorus.

[0040] 3) Under the condition of mechanical stirring, the roasted ore is subjected to water leaching. The stirring speed is 200 r / min, the water leaching temperature is 25 °C, and the reaction time is 5 h, so that indium enters the solution in the form of ions. Further, the slurry is filtered to separate insoluble impurities, and a leaching solution with the main component of In2(SO4)3-H2SO4 is obtained.

[0041] 4) Direct electrolysis is carried out on the leaching solution. Graphite plates are used as anodes and titanium plates are used as cathodes. The current density is controlled at 20 A / m 2 , and the temperature of the electrolyte solution is 25 °C, so that indium is reduced and precipitated at the cathode.

[0042] 5) The precipitated metallic indium is stripped from the cathode surface, and the recovered metallic indium is washed 4 times with deionized water and further dried at 70 °C for 96 h to obtain refined indium products.

[0043] By using the treatment method of this example, the recovery rates and purities of metallic indium and phosphorus pentoxide are analyzed by dissolving with aqua regia combined with inductively coupled plasma mass spectrometry (ICP-MS) and X-ray fluorescence spectrometer (XRF). The results show that the recovery rates of metallic indium and phosphorus pentoxide are 99.32% and 98.67% respectively, and the purities of metallic indium and phosphorus pentoxide are 99.996% and 99.18% respectively.

[0044] Example 2

[0045] A method for efficiently recovering refined indium from indium phosphide waste materials in this example specifically includes the following steps:

[0046] 1) The indium phosphide waste material powder pre-ground to less than 300 μm is mixed evenly with concentrated sulfuric acid with a purity of 98% at a ratio of V H2SO4 / m InP = 5 mL / g and placed in a tube furnace.

[0047] 2) Heat it to 450 °C at a rate of 20 °C / min and keep it at a constant temperature for 1 h. The whole process is carried out in a flowing air atmosphere, and the gas flow rate is 5 L / min, so that the insoluble indium phosphide is converted into indium sulfate that is easily soluble in water. At the same time, the volatile phosphorus pentoxide generated enters the condensation zone at a temperature of 150 °C with the flowing gas to realize the recovery of phosphorus.

[0048] 3) Under the condition of mechanical stirring, the roasted ore is subjected to water leaching. The stirring speed is 600 r / min, the water leaching temperature is 95 °C, and the reaction time is 1 h, so that indium enters the solution in the form of ions. Further, the slurry is filtered to separate insoluble impurities, and a leaching solution with the main component of In2(SO4)3-H2SO4 is obtained.

[0049] 4) Directly electrolyze the leaching solution, using a platinum plate as the anode and a stainless steel plate as the cathode, controlling the current density to be 100 A / m 2 , with the electrolyte temperature at 80 °C, to precipitate indium by reduction at the cathode.

[0050] 5) Strip the precipitated metallic indium from the cathode surface, wash the recovered metallic indium 8 times with deionized water, and further dry it at 110 °C for 24 h to obtain refined indium products.

[0051] Using the treatment method of this example, analyze the recovery rates and purities of indium and phosphorus pentoxide by dissolving with aqua regia combined with inductively coupled plasma mass spectrometry (ICP-MS) and X-ray fluorescence spectrometer (XRF). The results show that the recovery rates of indium and phosphorus pentoxide are 99.53% and 98.22% respectively, and the purities of indium and phosphorus pentoxide are 99.997% and 99.26% respectively.

[0052] Example 3

[0053] A method for efficiently recovering refined indium from indium phosphide waste in this example specifically includes the following steps:

[0054] 1) Mix the indium phosphide waste powder pre-ground to below 300 μm evenly with concentrated sulfuric acid with a purity of 98% at a ratio of V H2SO4 / m InP = 2 mL / g, and place it in a tubular furnace.

[0055] 2) Heat it to 370 °C at a rate of 10 °C / min and keep it at a constant temperature for 6 h. The whole process is carried out in a flowing oxygen atmosphere with a gas flow rate of 2 L / min, converting the insoluble indium phosphide into indium sulfate soluble in water. At the same time, the volatile phosphorus pentoxide generated enters the condensation zone at 120 °C with the flowing gas to achieve the recovery of phosphorus.

[0056] 3) Leach the calcine under mechanical stirring conditions, with a stirring speed of 300 r / min, a leaching temperature of 45 °C, and a reaction time of 4 h, to make indium enter the solution in ionic form. Further filter the slurry to separate insoluble impurities and obtain a pure leaching solution with the main component of In2(SO4)3-H2SO4.

[0057] 4) Directly electrolyze the leaching solution, using a graphite plate as the anode and a platinum plate as the cathode, controlling the current density to be 40 A / m 2 , with the electrolyte temperature at 40 °C, to precipitate indium by reduction at the cathode.

[0058] 5) Strip the precipitated metallic indium from the cathode surface, wash the recovered metallic indium 5 times with deionized water, and further dry it at 80 °C for 72 h to obtain refined indium products.

[0059] Using the treatment method of this embodiment, the recovery rates and purities of indium metal and phosphorus pentoxide were analyzed by dissolving in aqua regia in combination with an inductively coupled plasma mass spectrometer (ICP-MS) and an X-ray fluorescence spectrometer (XRF). The results showed that the recovery rates of indium metal and phosphorus pentoxide were 99.39% and 98.62% respectively, and the purities of indium metal and phosphorus pentoxide were 99.995% and 99.42% respectively.

[0060] Example 4

[0061] A method for efficiently recovering high-purity indium from indium phosphide waste materials in this embodiment specifically includes the following steps:

[0062] 1) Mix the indium phosphide waste material powder pre-milled to less than 300 μm evenly with concentrated sulfuric acid with a purity of 98% at a ratio of V H2SO4 / m InP = 3 mL / g, and place it in a tubular furnace.

[0063] 2) Heat it to 400 °C at a rate of 12 °C / min and keep it at a constant temperature for 4 h. The whole process is carried out in a flowing air atmosphere, and the gas flow rate is 3 L / min, so that the insoluble indium phosphide is converted into indium sulfate that is easily soluble in water, and at the same time, the volatile phosphorus pentoxide generated enters the condensation zone at a temperature of 130 °C with the flowing gas to achieve the recovery of phosphorus.

[0064] 3) Leach the calcined ore under mechanical stirring conditions. The stirring speed is 400 r / min, the leaching temperature is 60 °C, and the reaction time is 3 h, so that indium enters the solution in the form of ions. Further filter the slurry to separate the insoluble impurities and obtain a pure leaching solution with the main component of In2(SO4)3-H2SO4.

[0065] 4) Directly electrolyze the leaching solution. Use a platinum plate as the anode and a platinum plate as the cathode, control the current density to be 60 A / m 2 , and the temperature of the electrolyte is 55 °C, so that indium is reduced and precipitated at the cathode.

[0066] 5) Peel the precipitated indium metal from the cathode surface, wash the recovered indium metal 6 times with deionized water, and further dry it at 90 °C for 60 h to obtain a high-purity indium product.

[0067] Using the treatment method of this embodiment, the recovery rates and purities of indium metal and phosphorus pentoxide were analyzed by dissolving in aqua regia in combination with an inductively coupled plasma mass spectrometer (ICP-MS) and an X-ray fluorescence spectrometer (XRF). The results showed that the recovery rates of indium metal and phosphorus pentoxide were 99.51% and 98.48% respectively, and the purities of indium metal and phosphorus pentoxide were 99.997% and 99.59% respectively.

[0068] Example 5

[0069] A method for efficiently recovering high-purity indium from indium phosphide waste in this embodiment specifically includes the following steps:

[0070] 1) Mix the indium phosphide waste powder pre-milled to less than 300 μm evenly with concentrated sulfuric acid with a purity of 98% at a ratio of V H2SO4 / m InP = 4 mL / g, and place it in a tubular furnace.

[0071] 2) Heat it to 430 °C at a rate of 16 °C / min and keep it at a constant temperature for 2 h. The whole process is carried out in a flowing oxygen atmosphere with a gas flow rate of 4 L / min, so that the insoluble indium phosphide is converted into indium sulfate that is easily soluble in water, and at the same time, the volatile phosphorus pentoxide generated enters the condensation zone at a temperature of 140 °C with the flowing gas to achieve the recovery of phosphorus.

[0072] 3) Leach the calcine under mechanical stirring conditions. The stirring speed is 500 r / min, the leaching temperature is 80 °C, and the reaction time is 2 h, so that indium enters the solution in the form of ions. Further filter the slurry to separate insoluble impurities to obtain a pure leaching solution with the main component of In2(SO4)3-H2SO4.

[0073] 4) Directly electrolyze the leaching solution, use a graphite plate as the anode and a titanium plate as the cathode, control the current density to be 80 A / m 2 , and the temperature of the electrolyte is 70 °C, so that indium is reduced and precipitated at the cathode.

[0074] 5) Peel the precipitated metallic indium from the cathode surface, wash the recovered metallic indium 7 times with deionized water, and further dry it at 100 °C for 48 h to obtain a high-purity indium product.

[0075] Using the treatment method of this embodiment, analyze the recovery rate and purity of metallic indium and phosphorus pentoxide by dissolving with aqua regia combined with an inductively coupled plasma mass spectrometer (ICP-MS) and an X-ray fluorescence spectrometer (XRF). The results show that the recovery rates of metallic indium and phosphorus pentoxide are 99.68% and 98.53% respectively, and the purities of metallic indium and phosphorus pentoxide are 99.998% and 99.63% respectively.

[0076] The above-described preferred embodiments of the present invention disclosed are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor limit the invention to only the specific implementation manners. Obviously, according to the content of this specification, many modifications and changes can be made. This specification selects and specifically describes these embodiments to better explain the principle and practical application of the present invention, so that those skilled in the art in the relevant technical field can well understand and utilize the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A method for efficiently recycling high-purity indium from indium phosphide waste, characterized in that: First, the indium phosphide waste is subjected to sulfation roasting to break the stable covalent bond between indium and phosphorus, converting the insoluble indium phosphide into indium sulfate that is soluble in water. At the same time, phosphorus is recovered in the form of phosphorus pentoxide in the gas-phase condensation zone; the roasted ore is subjected to water leaching to allow indium to enter the solution in ionic form, forming a leaching solution mainly composed of In2(SO4)3-H2SO4; the leaching solution is directly electrolyzed, and by accurately controlling the electrochemical conditions, indium is reduced and precipitated at the cathode, while avoiding the precipitation of impurity ions, to obtain refined indium products; The specific process operations are as follows: 1) Mix the indium phosphide waste powder and concentrated sulfuric acid evenly in proportion and place them in a tubular furnace; 2) Heat up to 350-450 °C and keep the temperature constant for 1-8 h. The whole process is carried out in a flowing oxygen or air atmosphere. The heating rate is 5-20 °C / min, and the oxygen or air flow rate is 1-5 L / min; convert the insoluble indium phosphide into indium sulfate that is soluble in water, and at the same time, the volatile phosphorus pentoxide generated enters the condensation zone with the flowing gas to achieve the recovery of phosphorus; the temperature for recovering phosphorus pentoxide in the condensation zone is 110-150 °C; 3) Subject the roasted ore to water leaching to allow indium to enter the solution in ionic form, filter the slurry. The water leaching temperature is 25-95 °C, the reaction time is 1-5 h, and the mechanical stirring speed is 200-600 r / min; separate the insoluble impurities to obtain a pure leaching solution mainly composed of In2(SO4)3-H2SO4; 4) Directly electrolyze the leaching solution, and by accurately controlling the electrochemical conditions, reduce and precipitate indium at the cathode; 5) Strip the precipitated metallic indium from the cathode surface, wash it with deionized water and dry it to obtain refined indium products.

2. The method for efficiently recycling high-purity indium from indium phosphide waste according to claim 1, wherein: In step 1), the indium phosphide waste is pre-ground to less than 300 μm, and the purity of the concentrated sulfuric acid is 98%.

3. A method for efficiently recycling indium from indium phosphide waste according to claim 1, characterized in that: In step 1), the volume ratio of the concentrated sulfuric acid to the mass of the indium phosphide waste is 1-5 mL / g.

4. A method for efficiently recycling high-purity indium from indium phosphide waste according to claim 1, characterized in that: In step 4), the electrolysis system uses graphite or a platinum plate as the anode, and a titanium plate, a stainless steel plate or a platinum plate as the cathode. The current density during the electrolysis process is 20 - 100 A / m 2 , and the temperature of the electrolyte is 25 - 80 °C.

5. The method for efficiently recycling indium from indium phosphide waste according to claim 1 is characterized in that: In step 5), the recovered metallic indium is washed 4-8 times with deionized water and dried at 70-110 °C for 24-96 h to obtain refined indium products.