Method for recovering ITO (indium tin oxide) waste powder

Abstract

The embodiment of the invention discloses a method for recycling ITO waste powder, which comprises the following steps of: arranging an ITO waste target serving as an anode, an inert metal electrode serving as a cathode and NaOH, KOH or NaOH-KOH eutectic salt serving as a molten salt electrolyte in an electrolytic tank to form an electrolysis system; iTO waste powder is laid in the electrolytic tank, and the anode and the cathode are located above the ITO waste powder; the molten salt electrolyte is heated to the electrolysis temperature for constant-current electrolysis, the ITO waste powder reacts with the molten electrolyte to generate indate and stannate, the generated indate and stannate are reduced into metal tin and metal indium on the cathode, and indium-tin alloy is formed and deposited on the cathode; the ITO waste powder reacts with molten alkali to generate stannate and indate by adopting an electrolysis mode in a molten alkali environment, and the stannate and the indate are further electrolyzed and deposited at a cathode, so that the efficient dissolution of indium and tin in the waste ITO powder is realized. The method is high in comprehensive recovery efficiency of indium and tin, simple in operation process, low in energy consumption, environment-friendly and good in economical efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of target material recovery, and in particular relates to a method for recovering waste ITO powder. Background Art

[0002] ITO targets, composed of 90wt% In2O3 and 10wt% SnO2, are the primary consumer of indium metal, accounting for 70% of global indium consumption. ITO targets offer excellent conductivity, transmittance, and chemical stability, making them widely used in display devices such as LCDs, PDPs, and OLEDs. With the rapid adoption of electronic products in our lives, demand for ITO targets is also increasing. The ITO machining process generates a large amount of waste ITO powder. This waste ITO powder, which has the same composition as the ITO target, has enormous recycling potential and represents a potential treasure trove of indium metal.

[0003] Currently, the recycling methods for ITO mainly focus on waste ITO targets, and there are very few methods for recycling waste ITO powder. The main methods for recycling waste ITO targets are thermal reduction and acid leaching. The thermal reduction method has a high recovery rate and low energy consumption; however, this method has high processing costs and the reaction process is difficult to control. The acid leaching method is to dissolve In, Sn, etc. in the waste ITO targets in an acid solution, and then electrolyze the acid solution containing In and Sn ions to recover beneficial metals; however, this treatment method has a complex process, low efficiency, and too long a processing time. During the acid leaching process, the metal dissolution in the ITO powder is very limited, and a large amount of waste acid and other pollutants are generated during the treatment process, which is very harmful to humans and the environment. Summary of the Invention

[0004] In view of this, some embodiments disclose a method for recycling waste ITO powder, comprising:

[0005] An electrolysis system is formed by using an ITO waste target as an anode, an inert metal electrode as a cathode, and NaOH, KOH or NaOH-KOH eutectic salt as a molten salt electrolyte in an electrolytic cell.

[0006] ITO waste powder is laid in the electrolytic cell, and the anode and cathode are located above the ITO waste powder;

[0007] The molten salt electrolyte is heated to the electrolysis temperature and constant current electrolysis is performed. The ITO waste powder reacts with the molten electrolyte to generate indium salt and stannate. The generated indium salt and stannate are reduced to metallic tin and metallic indium on the cathode, forming an indium tin alloy deposited on the cathode.

[0008] Furthermore, some embodiments disclose a method for recycling waste ITO powder, wherein the electrolysis temperature is set to 180-300°C.

[0009] Some embodiments disclose a method for recycling waste ITO powder, wherein the electrolysis current density is set to 0.3-0.8 A / cm 2 .

[0010] Some embodiments disclose a method for recycling waste ITO powder, wherein the electrolysis time is set to 2 to 6 hours.

[0011] Some embodiments disclose a method for recycling waste ITO powder, wherein the electrolysis current efficiency is 30-75%.

[0012] Some embodiments disclose a method for recycling waste ITO powder, with a comprehensive product yield of 97-99.9%.

[0013] Some embodiments disclose a method for recycling waste ITO powder, which is performed in an electrolysis device, the electrolysis device comprising:

[0014] electrolytic cell;

[0015] A partition is vertically arranged in the electrolytic cell; the height of the partition is less than that of the electrolytic cell, forming two independent areas on both sides of the partition; one area is used to set the anode, and the other area is used to set the cathode; in the area where the cathode is set, a discharge port is set on the side wall of the electrolytic cell.

[0016] The waste ITO powder recovery method disclosed in the embodiments of the present invention utilizes electrolysis in a molten alkaline environment to cause the waste ITO powder to react with molten alkali to produce stannate and indium salts, which promotes further cathode electrolytic deposition and achieves efficient dissolution of indium and tin from the waste ITO powder. The waste ITO powder recovery method disclosed in the embodiments of the present invention achieves high comprehensive recovery efficiency of indium and tin, a simple operational process, low energy consumption, environmental friendliness, and good economic performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the electrolysis device in Example 1.

[0018] Reference numerals

[0019] 1 electrolytic cell 2 anode

[0020] 3 cathode 4 separator

[0021] 5Waste ITO powder 6Indium tin alloy

[0022] 7 electrolyte 8 discharge port DETAILED DESCRIPTION

[0023] The term "embodiment" is used herein specifically to describe any embodiment as "exemplary," and should not be construed as superior or preferable to other embodiments. Performance indicators in the embodiments of the present invention were tested using conventional testing methods in the art, unless otherwise specified. It should be understood that the terms used in the embodiments of the present invention are intended solely to describe specific implementations and are not intended to limit the disclosure of the embodiments of the present invention.

[0024] Unless otherwise specified, the technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art to which the embodiments of the present invention pertain; any experimental methods and technical means not otherwise specified in the embodiments of the present invention refer to experimental methods and technical means commonly used by those skilled in the art.

[0025] As used herein, the terms "substantially" and "approximately" are used to describe small fluctuations. For example, they can refer to less than or equal to ±5%, such as less than or equal to ±2%, such as less than or equal to ±1%, such as less than or equal to ±0.5%, such as less than or equal to ±0.2%, such as less than or equal to ±0.1%, such as less than or equal to ±0.05%. Numerical data expressed or presented in range format herein are used for convenience and brevity only and should therefore be interpreted flexibly to include not only the values explicitly listed as the limits of the range, but also all independent values or subranges contained within the range. For example, a numerical range of "1-5%" should be interpreted to include not only the explicitly listed values of 1% to 5%, but also the independent values and subranges within the indicated range. Thus, included in this numerical range are independent values such as 2%, 3.5%, and 4%, and subranges such as 1% to 3%, 2% to 4%, and 3% to 5%, etc. This principle also applies to ranges that only list a single value. Furthermore, this interpretation applies regardless of the width of the range or the characteristics described.

[0026] Throughout this document, including in the claims, transitional terms such as "comprises," "includes," "with," "having," "contains," "involving," and "accommodating" are understood to be open-ended, meaning "including but not limited to." Only the transitional terms "consisting of" and "composed of" are closed transitional terms.

[0027] In order to better illustrate the present invention, numerous specific details are provided in the following specific examples. It should be understood by those skilled in the art that the present invention can be practiced without certain specific details. In the examples, some methods, means, instruments, and equipment well known to those skilled in the art are not described in detail in order to highlight the main purpose of the present invention.

[0028] Under the premise of no conflict, the technical features disclosed in the embodiments of the present invention can be arbitrarily combined, and the resulting technical solutions belong to the contents disclosed in the embodiments of the present invention.

[0029] In some embodiments, the method for recycling waste ITO powder includes:

[0030] An electrolysis system is formed by using an ITO waste target as an anode, an inert metal electrode as a cathode, and NaOH, KOH or NaOH-KOH eutectic salt as a molten salt electrolyte in an electrolytic cell.

[0031] ITO waste powder is laid in the electrolytic cell, and the anode and cathode are located above the ITO waste powder;

[0032] The molten salt electrolyte is heated to the electrolysis temperature and subjected to constant current electrolysis. The ITO waste powder reacts with the molten electrolyte to form indium salts and stannates. These are then reduced to metallic tin and metallic indium at the cathode, forming an indium-tin alloy that is deposited at the cathode. The ITO waste powder typically laid in the electrolytic cell reacts with the molten electrolyte to form indium salts and stannates, which dissolve in the molten electrolyte. The ITO anode reacts very slowly in the molten alkali, forming a very small amount of indium salts and stannates on its surface, which also dissolve in the molten electrolyte. The stannates and indium salts in the molten electrolyte are further reduced at the cathode, forming an indium-tin alloy that is deposited on the cathode surface.

[0033] Some embodiments disclose a method for recycling waste ITO powder, wherein the electrolysis temperature is set at 180-300°C.

[0034] Some embodiments disclose a method for recycling waste ITO powder, wherein the electrolysis current density is set to 0.3-0.8 A / cm 2 .

[0035] Some embodiments disclose a method for recycling waste ITO powder, wherein the electrolysis time is set to 2 to 6 hours.

[0036] Some embodiments disclose a method for recycling waste ITO powder, wherein the electrolysis current efficiency is 30-75%. Generally, the current efficiency is calculated as follows:

[0037] Electrolysis current efficiency = cathode product mass ÷ (electrochemical equivalent × electrolysis time × current) × 100%.

[0038] Some embodiments disclose methods for recycling waste ITO powder, with a product comprehensive yield of 97-99.9%. Generally, the product comprehensive yield is calculated as follows:

[0039] Comprehensive product yield = (mass of cathode product + mass of anode precipitation × 114.8 ÷ 165.8) ÷ (mass of anode consumption × 229.6 ÷ 277.6) × 100%.

[0040] Some embodiments disclose a method for recycling waste ITO powder, which is performed in an electrolysis device, the electrolysis device comprising:

[0041] An electrolytic cell; a separator vertically disposed within the cell; the separator is shorter than the cell, forming two separate areas on either side of the separator; one area is used to accommodate the anode, and the other area is used to accommodate the cathode; a discharge port is provided on the side wall of the cell in the cathode area. The generated indium tin alloy can typically be collected from the discharge port.

[0042] The waste ITO powder recovery method disclosed in the embodiments of the present invention utilizes electrolysis in a molten alkaline environment to cause the waste ITO powder to react with molten alkali to produce stannate and indium salts, which promotes further cathode electrolytic deposition and achieves efficient dissolution of indium and tin from the waste ITO powder. The waste ITO powder recovery method disclosed in the embodiments of the present invention achieves high comprehensive recovery efficiency of indium and tin, a simple operational process, low energy consumption, environmental friendliness, and good economic performance.

[0043] The technical details are further illustrated below with reference to embodiments.

[0044] Example 1

[0045] Example 1 discloses a method for recycling waste ITO powder, comprising:

[0046] like Figure 1 As shown, an ITO waste target is used as the anode 2, and titanium is used as the cathode 3; a partition 4 is vertically arranged in the electrolytic cell 1, and the partition 4 is fixed to the bottom and side wall of the electrolytic cell 1; a discharge port 8 is provided on the side wall of the electrolytic cell 1; the anode 2 and the cathode 3 are respectively arranged in the electrolytic cell 1 on both sides of the partition 4;

[0047] The waste ITO powder 5 was laid under the anode 2, and NaOH was added into the device as the electrolyte 7; the liquid level of the molten electrolyte 7 was higher than the separator 4; the electrolysis temperature was set to 180 ° C and the current density was set to 0.3 A / cm 2 , connect the power supply and electrolyze for 2h;

[0048] An indium tin alloy 6 is obtained on the cathode 3; the comprehensive yield of the product is 97.2%, and the current efficiency is 33%.

[0049] Example 2

[0050] Example 2 discloses a method for recycling waste ITO powder, comprising:

[0051] The ITO waste target was used as the anode and tungsten was used as the cathode;

[0052] The waste ITO powder was laid under the ITO anode, and KOH was added into the device as the electrolyte; the electrolysis temperature was set to 200 ° C and the current density was set to 0.5 A / cm 2, connect the power supply and electrolyze for 3 hours;

[0053] Indium tin alloy is obtained on the cathode; the comprehensive yield of the product is 97.6% and the current efficiency is 42%.

[0054] Example 3

[0055] Example 3 discloses a method for recycling waste ITO powder, comprising:

[0056] The ITO waste target was used as the anode and molybdenum was used as the cathode;

[0057] The waste ITO powder was laid under the ITO anode, and NaOH-KOH was added into the device as the electrolyte; the temperature was set to 250 ° C and the current density was set to 0.8 A / cm 2 , connect the power supply and electrolyze for 6 hours;

[0058] Indium tin alloy is obtained on the cathode; the comprehensive yield of the product is 98.3% and the current efficiency is 54%.

[0059] Example 4

[0060] Example 4 discloses a method for recycling waste ITO powder, comprising:

[0061] The ITO waste target was used as the anode and titanium was used as the cathode;

[0062] The waste ITO powder was laid under the ITO anode, and KOH was added into the device as the electrolyte; the temperature was set to 250 ° C and the current density was set to 0.5 A / cm 2 , connect the power supply and electrolyze for 4 hours;

[0063] Indium tin alloy is obtained on the cathode; the comprehensive yield of the product is 98.6% and the current efficiency is 59%.

[0064] Example 5

[0065] Example 5 discloses a method for recycling waste ITO powder, comprising:

[0066] The ITO waste target was used as the anode and tungsten was used as the cathode;

[0067] The waste ITO powder was laid under the ITO anode, and NaOH-KOH was added into the device as the electrolyte; the temperature was set to 250 ° C and the current density was set to 0.5 A / cm 2 , connect the power supply and electrolyze for 6 hours;

[0068] Indium tin alloy is obtained on the cathode; the comprehensive yield of the product is 99.2% and the current efficiency is 63%.

[0069] Example 6

[0070] Example 6 discloses a method for recycling waste ITO powder, comprising:

[0071] The ITO waste target was used as the anode and molybdenum was used as the cathode;

[0072] The waste ITO powder was laid under the ITO anode, and NaOH-KOH was added into the device as the electrolyte; the temperature was set to 300 °C and the current density was set to 0.5 A / cm 2 , connect the power supply and electrolyze for 6 hours;

[0073] Indium tin alloy is obtained on the cathode; the comprehensive yield of the product is 99.5% and the current efficiency is 70%.

[0074] Example 7

[0075] Example 7 discloses a method for recycling waste ITO powder, comprising:

[0076] The ITO waste target was used as the anode and titanium was used as the cathode;

[0077] The waste ITO powder was laid under the ITO anode, and NaOH-KOH was added into the device as the electrolyte; the temperature was set to 300 °C and the current density was set to 0.8 A / cm 2 , connect the power supply and electrolyze for 4 hours;

[0078] Indium tin alloy is obtained on the cathode; the comprehensive yield of the product is 99.8% and the current efficiency is 68%.

[0079] Example 8

[0080] Example 8 discloses a method for recycling waste ITO powder, comprising:

[0081] The ITO waste target was used as the anode and molybdenum was used as the cathode;

[0082] The waste ITO powder was laid under the ITO anode, and NaOH-KOH was added to the device as the electrolyte. The temperature was set to 300 ° C and the current density was set to 0.8 A / cm 2 , connect the power supply and electrolyze for 6 hours;

[0083] Indium tin alloy is obtained on the cathode; the comprehensive yield of the product is 99.9% and the current efficiency is 73%.

[0084] From Examples 1 to 8, it can be seen that in the method for recycling ITO waste powder disclosed in the embodiments of the present invention, the greater the concentration of the electrolyte solution, the greater the current density, and the longer the electrolysis time, the higher the comprehensive yield of the product and the higher the current efficiency.

[0085] The waste ITO powder recovery method disclosed in an embodiment of the present invention utilizes molten alkali to electrolyze waste ITO powder, producing an indium-tin alloy at the cathode. In this method, waste ITO powder reacts with molten alkali in a molten alkali environment to form indium salts and stannates, which are then electrolyzed to form an In-Sn alloy. This allows for efficient dissolution and recovery of indium and tin from waste ITO powder. The method achieves high comprehensive recovery efficiency of indium and tin, a simple operating process, low energy consumption, environmental friendliness, and excellent economic benefits.

[0086] The technical solutions and technical details disclosed in the embodiments of the present invention are merely illustrative of the inventive concept of the present invention and do not constitute a limitation on the technical solutions of the embodiments of the present invention. Any conventional changes, replacements or combinations of the technical details disclosed in the embodiments of the present invention have the same inventive concept as the present invention and are within the scope of protection of the claims of the present invention.

Claims

1. A method for recovering ITO waste powder, characterized in that: include: An electrolysis system is formed by using an ITO waste target as an anode, an inert metal electrode as a cathode, and NaOH, KOH or NaOH-KOH eutectic salt as a molten salt electrolyte in an electrolytic cell. ITO waste powder is laid in the electrolytic cell, and the anode and cathode are located above the ITO waste powder; The molten salt electrolyte is heated to the electrolysis temperature and constant current electrolysis is performed. The ITO waste powder reacts with the molten electrolyte to generate indium salt and stannate. The generated indium salt and stannate are reduced to metallic tin and metallic indium on the cathode, forming an indium tin alloy deposited on the cathode.

2. The method for recovering ITO waste powder according to claim 1, wherein The electrolysis temperature is set to 180-300°C.

3. The method for recovering ITO waste powder according to claim 1, wherein The electrolysis current density was set to 0.3-0.8 A / cm 2 .

4. The method for recovering ITO waste powder according to claim 1, wherein The electrolysis time is set to 2 to 6 hours.

5. The method for recovering ITO waste powder according to claim 1, wherein The electrolysis current efficiency is 30-75%.

6. The method for recovering ITO waste powder according to claim 1, wherein The comprehensive yield of the product is 97-99.9%.

7. The method for recovering ITO waste powder according to claim 1, wherein: The method is carried out in an electrolysis device, which comprises: electrolytic cell; A partition is vertically arranged in the electrolytic cell; the height of the partition is less than the height of the electrolytic cell, and two independent areas are formed on both sides of the partition; one area is used to set the anode, and the other area is used to set the cathode; in the area where the cathode is set, a discharge port is provided on the side wall of the electrolytic cell.

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