Method for extracting strategic metals such as tin, indium and like from solid wastes in semiconductor and photovoltaic industries

Abstract

The invention relates to a method for extracting strategic metals such as tin, indium and the like from solid wastes in semiconductor and photovoltaic industries, and belongs to the technical field of solid waste resource recycling. The method comprises the following steps: carrying out crushing and grinding pretreatment on solid wastes including waste quartz boats, cut silicon sludge, waste sputtering targets and the like; then, the uniform powder is subjected to melting roasting, then acid is added for acid leaching treatment, and target metal ions are transferred into a solution; and finally, separating and enriching high-purity tin oxide and indium oxide products from the leachate by adopting a selective precipitation technology. The indium oxide and tin oxide materials prepared by the method have the characteristics of good electrical and optical properties, high raw material utilization efficiency and the like, and a thought is provided for high-value resource utilization of solid wastes in semiconductor and photovoltaic industries. According to the method, high-value rare metal in the semiconductor waste is recycled, waste is turned into wealth, the process is reasonable, the recycling rate is high, and remarkable economic and environmental benefits are achieved.

Description

Technical Field

[0001] This invention belongs to the field of solid waste resource recycling technology, specifically relating to a method for extracting strategic metals such as tin and indium from solid waste from the semiconductor and photovoltaic industries. Background Technology

[0002] The semiconductor and photovoltaic industries are core components supporting modern information technology and clean energy strategies. However, their manufacturing processes generate a large amount of complex and difficult-to-treat solid waste. This includes discarded quartz boats, quartz blocks, cut silicon sludge, waste sputtering targets, and chemical vapor deposition waste. Currently, solid waste from the semiconductor and photovoltaic industries is often disposed of through landfill, which not only pollutes the environment but also wastes strategic metal resources such as tin and indium. Rare metals such as Sn and In, as important components of the photovoltaic industry, are characterized by extremely low abundance and dispersed distribution in the Earth's crust, and their prices fluctuate wildly.

[0003] Currently, recovering rare metals such as Sn and In from these solid wastes faces severe challenges: First, the material sources are complex, with the matrix mostly consisting of chemically stable silicate glass or crystalline silicon, which traditional acids struggle to effectively decompose. Second, the target metals, tin and indium, are present in low concentrations and diverse states, often existing as dopants or solid solutions in solid wastes, making separation and purification difficult. Therefore, the industry urgently needs to develop an innovative method that can adapt to complex materials, has an efficient processing flow, is environmentally friendly, and can achieve highly selective recovery of tin, indium, and other rare metals. Summary of the Invention

[0004] The problem the invention aims to solve

[0005] The purpose of this invention is to solve the comprehensive industrial problems in the semiconductor and photovoltaic industries, which include environmental pollution caused by the large-scale accumulation of solid waste, the security crisis of rare metal resources such as Sn and In, and technological bottlenecks.

[0006] Solution for solving the problem

[0007] To address the aforementioned issues, an innovative route of "alkali fusion activation-acid leaching-selective separation" was developed using solid waste from the semiconductor and photovoltaic industries as raw materials, achieving the transformation of hazardous solid waste into high-purity strategic metals. This yielded tin oxide products with a purity of over 99.95% and a recovery rate of over 85%, and indium oxide products with a purity of over 99.99% and a recovery rate of over 90%. This fundamentally promotes the high-value resource utilization of solid waste from the semiconductor and photovoltaic industries, achieving a win-win situation for both environmental and economic benefits.

[0008] Specifically, in order to solve the above problems, the present invention provides the following technical solution:

[0009] [1] A method for extracting strategic metals such as tin and indium from solid waste from the semiconductor and photovoltaic industries, comprising the following steps:

[0010] S1: Clean, dry, crush and grind the solid waste obtained from the semiconductor and photovoltaic industries to obtain uniform powder;

[0011] S2: Mix the uniform powder obtained in step S1 with the alkaline flux until uniform, carry out the melting reaction at high temperature, and obtain the molten product after cooling;

[0012] S3: Add acid to the molten product obtained in step S2 for acid leaching treatment, and after solid-liquid separation, obtain a leachate rich in tin and indium;

[0013] S4: Separate and enrich the target rare metals tin and indium from the leachate obtained in step S3.

[0014] [2] According to the method described in [1], the solid waste in the semiconductor and photovoltaic industry includes, but is not limited to, waste quartz boats, waste quartz blocks, silicon wafer cutting waste, waste sputtering targets, CVD waste and scraps from photovoltaic thin film battery production; the particle size of the solid waste powder obtained by grinding is controlled between 150 mesh and 500 mesh.

[0015] [3] According to the method described in [1-2], the alkaline flux in step S2 is one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate, and the mass ratio of the solid waste powder to the alkaline flux is 1:0.5 to 1:5; the melting reaction temperature is 400 ℃ to 900 ℃, the reaction time is 0.5 h to 6 h, and the heating rate is 5-10 ℃min. -1 The atmosphere is air or oxygen.

[0016] [4] According to the method described in [1-3], the acid in step S3 is one or more of hydrochloric acid, sulfuric acid, and nitric acid; the acid concentration is 0.5 mol / l to 10 mol / l; the acid leaching temperature is 30-95 ℃ and the acid leaching time is 1-6 h.

[0017] [5] According to the method described in [1-4], the method is characterized in that, in step S4, a selective precipitation separation method is used, and the pH value of the leachate is adjusted. When the pH value is between 1 and 3, the product is obtained by filtration and drying. When the pH value is between 4 and 5, the product is obtained by drying and calcining. The calcination temperature is between 400 and 800 °C; the holding time is 2-6 h; and the heating rate is 5-10 °C / min. -1 The atmosphere is air or oxygen.

[0018] [6] The method according to any one of [1-5] is characterized in that the purity of the tin oxide product obtained in step S4 is above 99.95% and the recovery rate is above 85%, and the purity of the indium oxide product is above 99.99% and the recovery rate is above 90%.

[0019] [7] The method according to [1-6] is characterized in that the solid secondary quartz powder obtained by solid-liquid separation after acid leaching can be reused, and the acid solution generated by acid leaching can be recycled.

[0020] The effects of the invention

[0021] Compared with existing technologies, this invention provides a method for extracting rare metals such as tin and indium. Specifically, this invention has the following beneficial effects:

[0022] (1) This invention converts hazardous waste into rare metals, solves the environmental problems of the semiconductor and photovoltaic industries, and creates certain economic value.

[0023] (2) In the acid leaching process, the present invention avoids the use of highly toxic hydrofluoric acid as a solvent, making the production process more environmentally friendly and safer. In addition, the waste liquid is recycled and reused, and the quartz powder and other materials generated in the process can be used as other industrial raw materials, realizing the comprehensive utilization of all components.

[0024] (3) The indium oxide and tin oxide prepared by the present invention have high purity and high recovery rate, and have good electrical and optical properties.

[0025] This method successfully achieves efficient recycling and value creation of solid waste from the semiconductor and photovoltaic industries in an environmentally friendly manner. While "turning waste into treasure", it also reduces costs and increases efficiency, providing strong technical support for the green circular economy development of the semiconductor industry, and has extremely broad market prospects. Detailed Implementation

[0026] Various exemplary embodiments, features, and aspects of the present invention will be described in detail below. The term "exemplary" as used herein means "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as superior to or better than other embodiments.

[0027] Furthermore, to better illustrate the present invention, numerous specific details are set forth in the following detailed embodiments. Those skilled in the art should understand that the present invention can be practiced without certain specific details. In other instances, methods, means, apparatus, and steps well known to those skilled in the art have not been described in detail in order to highlight the spirit of the present invention.

[0028] Unless otherwise stated, all units used in this specification are international standard units, and all numerical values ​​and ranges appearing in this invention should be understood to include systematic errors that are unavoidable in industrial production.

[0029] In this specification, the word "may" has two meanings: to perform a certain process and not to perform a certain process.

[0030] In this specification, references to "some specific / preferred embodiments," "other specific / preferred embodiments," "implementation," etc., refer to specific elements (e.g., features, structures, properties, and / or characteristics) related to that embodiment, which are included in at least one of the embodiments described herein and may or may not be present in other embodiments. Furthermore, it should be understood that these elements may be combined in any suitable manner in various embodiments.

[0031] In this specification, the range of values ​​referred to as “value A - value B” is the range that includes the endpoint values ​​A and B.

[0032] In this specification, the range of values ​​referred to as "above value A" or "below value A" refers to the range including the endpoint value A.

[0033] In this instruction manual, when "room temperature" or "room temperature" is used, the temperature can be 15-30℃, or further 15-25℃, such as 20℃, 25℃, etc.

[0034] Example

[0035] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0036] Example 1

[0037] (1) Collect waste quartz boats obtained from the semiconductor and photovoltaic industries, use deionized water for ultrasonic cleaning to remove surface dust and residues, then dry them in an oven at 120 ℃ for 24 h, and further crush and grind them using a crusher, and sieve them to obtain uniform powder with a particle size of 200 mesh.

[0038] (2) The 200-mesh uniform powder obtained in step (1) and potassium hydroxide alkaline flux are mixed with 5 g of potassium hydroxide at a mass ratio of 1:0.5 by grinding until uniform, and then heated at 5 °C for min. -1The heating rate was set at 500 °C for 4 h in a muffle furnace to carry out the melting reaction, and the molten product was obtained after cooling.

[0039] (3) The molten product obtained in step (2) was added to a mixed acid system (hydrochloric acid: sulfuric acid = 1:1, volume ratio, total concentration of 6 mol / L) for acid leaching treatment. The acid leaching temperature was 80 °C and the time was 4 h. After the reaction was completed and allowed to cool naturally, the product was centrifuged at 10000 rpm for 20 min. The solid and the leaching liquid rich in tin and indium were collected respectively. The solid was dried to obtain secondary quartz powder.

[0040] (4) Adjust the pH value of the leachate obtained in step (3). When the pH is 2, tin hydroxide is preferentially precipitated. When the pH is further adjusted to 5, indium hydroxide is precipitated. Further, tin hydroxide and indium hydroxide are placed in a muffle furnace at 800 °C and kept at a temperature of 5 °C / min for 3 h. -1 Tin oxide and indium oxide were obtained. Inductively coupled plasma mass spectrometry (ICP-MS) analysis showed that the purity of tin oxide was 99.956% and that of indium oxide was 99.995%. Comparison of the obtained product mass with the original mass yielded a recovery rate of 86.2% for tin oxide and 90.3% for indium oxide.

[0041] Example 2

[0042] (1) Collect CVD waste obtained from the semiconductor and photovoltaic industries, use deionized water for ultrasonic cleaning to remove surface dust and residues, then dry in an oven at 120 ℃ for 24 h, further crush and grind using a crusher, and sieve to obtain uniform powder with a particle size of 400 mesh.

[0043] (2) The 400-mesh uniform powder obtained in step (1) and potassium hydroxide alkaline flux are mixed with 20 g of potassium hydroxide at a mass ratio of 1:2 and then ground until uniform. Then, the mixture is heated at 5 °C for 1 min. -1 The heating rate was set at 800 °C in a muffle furnace for 3 hours to carry out the melting reaction, and the molten product was obtained after cooling.

[0044] (3) The molten product obtained in step (2) was added to a mixed acid system (hydrochloric acid: sulfuric acid = 2:1, volume ratio, total concentration of 8 mol / L) for acid leaching treatment. The acid leaching temperature was 90 °C and the time was 3 h. After the reaction was completed and allowed to cool naturally, the product was centrifuged at 10000 rpm for 20 min. The solid and the leaching liquid rich in tin and indium were collected respectively. The solid was dried to obtain secondary quartz powder.

[0045] (4) Adjust the pH value of the leachate obtained in step (3). When the pH is 1, tin hydroxide is preferentially precipitated. When the pH is further adjusted to 4, indium hydroxide is precipitated. Further, tin hydroxide and indium hydroxide are placed in a muffle furnace at 700℃ and kept at a heating rate of 5℃ / min for 3 hours. -1 Tin oxide and indium oxide were obtained. Inductively coupled plasma mass spectrometry (ICP-MS) analysis showed that the purity of tin oxide was 99.950% and that of indium oxide was 99.992%. Comparison of the obtained product mass with the original mass yielded a recovery rate of 87.0% for tin oxide and 90.5% for indium oxide.

[0046] Example 3

[0047] (1) Collect waste quartz blocks obtained from the semiconductor and photovoltaic industries, use deionized water for ultrasonic cleaning to remove surface dust and residues, then dry them in an oven at 120 ℃ for 24 h, further crush and grind them using a crusher, and sieve them to obtain uniform powder with a particle size of 300 mesh.

[0048] (2) The 300-mesh uniform powder obtained in step (1) and potassium hydroxide alkaline flux are mixed with 10 g of potassium hydroxide at a mass ratio of 1:1 and then ground until uniform. Then, the mixture is heated at 5 °C for 1 min. -1 The heating rate was set at 700 °C in a muffle furnace for 3 hours to carry out the melting reaction, and the molten product was obtained after cooling.

[0049] (3) The molten product obtained in step (2) was added to a mixed acid system (hydrochloric acid: sulfuric acid = 2:1, volume ratio, total concentration of 5 mol / L) for acid leaching treatment. The acid leaching temperature was 80 ℃ and the time was 4 h. After the reaction was completed and allowed to cool naturally, the product was centrifuged at 10000 rpm for 20 min. The solid and the leaching liquid rich in tin and indium were collected respectively. The solid was dried to obtain secondary quartz powder.

[0050] (4) Adjust the pH value of the leachate obtained in step (3). When the pH is 1, tin hydroxide is preferentially precipitated. When the pH is further adjusted to 4, indium hydroxide is precipitated. Further, tin hydroxide and indium hydroxide are placed in a muffle furnace at 600 °C and kept at a temperature of 5 °C / min for 2 h. -1 Tin oxide and indium oxide were obtained. Inductively coupled plasma mass spectrometry (ICP-MS) analysis showed that the purity of tin oxide was 99.954% and that of indium oxide was 99.997%. Comparison of the obtained product mass with the original mass yielded a recovery rate of 85.1% for tin oxide and 91.7% for indium oxide.

[0051] Example 4

[0052] (1) Collect silicon wafer cutting waste obtained from the semiconductor and photovoltaic industries, use deionized water for ultrasonic cleaning to remove surface dust and residues, then dry in an oven at 120 ℃ for 24 h, further crush and grind using a crusher, and sieve to obtain uniform powder with a particle size of 400 mesh.

[0053] (2) The 400-mesh uniform powder obtained in step (1) and potassium hydroxide alkaline flux are mixed with 10 g of potassium hydroxide at a mass ratio of 1:1 and then ground until uniform. Then, the mixture is heated at 5 °C for 1 min. -1 The heating rate was set at 500 °C for 4 hours in a muffle furnace to carry out the melting reaction, and the molten product was obtained after cooling.

[0054] (3) The molten product obtained in step (2) was added to a mixed acid system (hydrochloric acid: sulfuric acid = 3:2, volume ratio, total concentration of 5 mol / L) for acid leaching treatment. The acid leaching temperature was 70 °C and the time was 3 h. After the reaction was completed and allowed to cool naturally, the product was centrifuged at 10000 rpm for 20 min. The solid and the leaching liquid rich in tin and indium were collected separately. The solid was dried to obtain secondary quartz powder.

[0055] (4) Adjust the pH value of the leachate obtained in step (3). When the pH is 2, tin hydroxide is preferentially precipitated. When the pH is further adjusted to 4, indium hydroxide is precipitated. Further, tin hydroxide and indium hydroxide are placed in a muffle furnace at 700 °C and kept at a temperature of 5 °C / min for 3 h. -1 Tin oxide and indium oxide were obtained. Inductively coupled plasma mass spectrometry (ICP-MS) analysis showed that the purity of tin oxide was 99.951% and that of indium oxide was 99.996%. Comparison of the obtained product mass with the original mass yielded a recovery rate of 85.5% for tin oxide and 91.2% for indium oxide.

[0056] Comparative Example 1

[0057] (1) Collect waste quartz boats obtained from the semiconductor and photovoltaic industries, use deionized water for ultrasonic cleaning to remove surface dust and residues, then dry them in an oven at 120 ℃ for 24 h, and further crush and grind them using a crusher, and sieve them to obtain uniform powder with a particle size of 200 mesh.

[0058] (2) The uniform powder obtained in step (1) was added to a mixed acid system (hydrochloric acid: sulfuric acid = 1:1, volume ratio, total concentration of 6 mol / L) for acid leaching treatment. The acid leaching temperature was 80 ℃ and the time was 4 h. After the reaction was completed and allowed to cool naturally, the mixture was centrifuged at 10000 rpm for 20 min. The solid and the leaching liquid rich in tin and indium were collected respectively. The solid was dried to obtain secondary quartz powder.

[0059] (3) Adjust the pH value of the leachate obtained in step (2). When the pH is 2, tin hydroxide is preferentially precipitated. When the pH is further adjusted to 5, indium hydroxide is precipitated. Further, tin hydroxide and indium hydroxide are placed in a muffle furnace at 800 °C and kept at a temperature of 5 °C / min for 3 h. -1 Tin oxide and indium oxide were obtained. Inductively coupled plasma mass spectrometry (ICP-MS) analysis showed that the purity of tin oxide was 76.756% and that of indium oxide was 43.563%. Comparison of the obtained product mass with the original mass yielded a recovery rate of 25% for tin oxide and 5% for indium oxide.

[0060] Comparative Example 2

[0061] (1) Collect waste quartz boats obtained from the semiconductor and photovoltaic industries, use deionized water for ultrasonic cleaning to remove surface dust and residues, then dry them in an oven at 120 ℃ for 24 h, and further crush and grind them using a crusher, and sieve them to obtain uniform powder with a particle size of 200 mesh.

[0062] (2) The 200-mesh uniform powder obtained in step (1) and potassium hydroxide alkaline flux are mixed with 5 g of potassium hydroxide at a mass ratio of 1:0.5 by grinding until uniform, and then heated at 5 °C for min. -1 The heating rate was set at 500 °C for 4 h in a muffle furnace to carry out the melting reaction, and the molten product was obtained after cooling.

[0063] (3) Add hydrofluoric acid to the molten product obtained in step (2) at a concentration of 6 mol / L for acid leaching treatment at a temperature of 80 °C for 4 h. After the reaction is completed and the product is allowed to cool naturally, centrifuge at 10000 rpm for 20 min and collect the solid and the leaching liquid rich in tin and indium respectively. The solid is dried to obtain secondary quartz powder.

[0064] (4) Adjust the pH value of the leachate obtained in step (3). When the pH is 2, tin hydroxide is preferentially precipitated. When the pH is further adjusted to 5, indium hydroxide is precipitated. Further, tin hydroxide and indium hydroxide are placed in a muffle furnace at 800 °C and kept at a temperature of 5 °C / min for 3 h. -1 Tin oxide and indium oxide were obtained. Inductively coupled plasma mass spectrometry (ICP-MS) analysis showed that the purity of tin oxide was 99.953% and that of indium oxide was 99.997%. Comparison of the obtained product mass with the original mass yielded a recovery rate of 86.0% for tin oxide and 90.1% for indium oxide.

[0065] It should be noted that although the technical solution of the present invention has been described with specific examples, those skilled in the art will understand that the present invention should not be limited thereto.

[0066] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for extracting strategic metals such as tin and indium from solid waste from the semiconductor and photovoltaic industries, characterized in that: The method for preparing indium oxide and tin oxide materials extracted from the waste quartz boat includes the following steps: S1: Clean, dry, crush and grind the solid waste obtained from the semiconductor and photovoltaic industries to obtain uniform powder; S2: Mix the uniform powder obtained in step S1 with the alkaline flux until uniform, carry out the melting reaction at high temperature, and obtain the molten product after cooling; S3: Add acid to the molten product obtained in step S2 for acid leaching treatment, and after solid-liquid separation, obtain a leachate rich in tin and indium; S4: Separate and enrich the target rare metals tin and indium from the leachate obtained in step S3.

2. The method according to claim 1, characterized in that: In step S1, the solid waste from the semiconductor and photovoltaic industry includes, but is not limited to, waste quartz boats, waste quartz blocks, silicon wafer cutting waste, waste sputtering targets, CVD waste, and scraps from photovoltaic thin-film battery production; the particle size of the solid waste powder obtained by grinding is controlled between 150 mesh and 500 mesh.

3. The method according to claims 1-2, characterized in that: In step S2, the alkaline flux is one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate; the mass ratio of the solid waste powder to the alkaline flux is 1:0.5 to 1:5; the melting reaction temperature is 400 ℃ to 900 ℃, the reaction time is 0.5 h to 6 h, and the heating rate is 5-10 ℃min. -1 The atmosphere is air or oxygen.

4. The method according to claims 1-3, characterized in that: The acid mentioned in step S3 is one or more of hydrochloric acid, sulfuric acid, and nitric acid; the concentration of the acid is 0.5 mol / L to 10 mol / L; the acid leaching temperature is 30-95 ℃, and the acid leaching time is 1-6 h.

5. The method according to claims 1-4, characterized in that, In step S4, a selective precipitation separation method is used. By adjusting the pH value of the leaching solution, tin oxide is obtained by drying and calcining when the pH value is between 1 and 3, and indium oxide is obtained by drying and calcining when the pH value is between 4 and 5. The calcination temperature is between 400 and 800 °C; the holding time is 2-6 h; and the heating rate is 5-10 °C / min. -1 The atmosphere is air or oxygen.

6. The method according to any one of claims 1-5, characterized in that, The tin oxide product obtained in step S4 has a purity of over 99.95% and a recovery rate of over 85%, while the indium oxide product has a purity of over 99.99% and a recovery rate of over 90%.

7. The method according to claims 1-6, characterized in that, The solid secondary quartz powder obtained after solid-liquid separation after acid leaching can be reused, and the acid solution generated by acid leaching can be recycled.