阅读说明：本技术 一种从ito残靶/废靶中回收ito粉末的方法 (Method for recovering ITO powder from ITO residual target/waste target ) 是由 蔡小勇 张科 李康 *** 于 2020-06-08 设计创作，主要内容包括：本发明提供了一种从ITO残靶/废靶中回收ITO粉末的方法,涉及光电材料循环利用技术领域。本发明通过ITO残靶/废靶表面清洁和酸洗、热应力破碎处理、环辊磨破碎处理、气流破碎处理和振动球磨处理,将ITO残靶/废靶加工成粒径为100～500nm的ITO纳米粉末。本发明提供的方法将ITO残靶/废靶加工成可直接用于ITO靶材制备的ITO粉末,且过程简单、节能环保、生产成本低,适合大规模生产；同时,回收得到的ITO粉末纯度很高,可达99.99％,也大大提高了废靶的回收率,废靶的回收率大于98％。(The invention provides a method for recovering ITO powder from an ITO residual target/waste target, and relates to the technical field of photoelectric material recycling. The method comprises the steps of cleaning and acid washing the surface of the ITO residual target/waste target, carrying out thermal stress crushing treatment, carrying out ring roller grinding crushing treatment, carrying out airflow crushing treatment and carrying out vibration ball milling treatment, and processing the ITO residual target/waste target into ITO nano powder with the particle size of 100-500 nm. The method provided by the invention processes the ITO residual target/waste target into ITO powder which can be directly used for preparing the ITO target material, and has the advantages of simple process, energy saving, environmental protection, low production cost and suitability for large-scale production; meanwhile, the purity of the recovered ITO powder is high and can reach 99.99%, the recovery rate of the waste target is greatly improved, and the recovery rate of the waste target is more than 98%.)

1. A method for recovering ITO powder from an ITO residual target/waste target is characterized by comprising the following steps:

(1) pickling the ITO residual target/waste target with a clean surface by using strong acid to obtain an indium-removing target material;

(2) heating and insulating the indium-removing target material under the condition of introducing oxygen, and then soaking the insulated target material into water for quenching to carry out thermal stress crushing to obtain ITO particles with the particle size of 5-10 mm;

(3) performing ring rolling crushing treatment on the ITO particles with the particle size of 5-10 mm to obtain ITO powder with the particle size of 0.5-1 mm;

(4) carrying out airflow crushing treatment on the ITO powder with the particle size of 0.5-1 mm, and screening to obtain ITO powder with the particle size of less than or equal to 5 micrometers;

(5) and carrying out vibration ball milling treatment on the ITO powder with the particle size of less than or equal to 5 microns to obtain the ITO powder with the particle size of 100-500 nm.

2. The method according to claim 1, wherein the flow rate of the oxygen introduced in the step (2) is 100-120L/min; the heating and heat preservation temperature is 1200-1400 ℃, and the heat preservation time is 2-5 h.

3. The method according to claim 1 or 2, wherein the step (2) of performing thermal stress cracking further comprises drying the ITO particles obtained by cracking after removing the ITO particles from water.

4. The method according to claim 1, characterized in that the ring roll mill crushing treatment in the step (3) is performed in a vertical ring roll mill; the rotating speed of the main shaft of the vertical ring roller mill is 180-200 r/min.

5. The method of claim 1, wherein the step (3) further comprises acid washing the ITO powder obtained after crushing with a strong acid after the ring roll crushing treatment.

6. The method according to claim 1 or 5, wherein the step (1) or step (3) after acid washing independently further comprises sequentially subjecting the acid-washed ITO product to ultrasonic washing and drying; the ultrasonic cleaning adopts water as a cleaning agent.

7. The method as claimed in claim 1, wherein the air stream-breaking treatment in the step (4) is performed in an impact jet mill; the impact plate of the impact type jet mill is an ITO plate.

8. The method according to claim 1, wherein the vibratory ball milling treatment in step (5) is performed in a vibratory ball mill; the vibration frequency of the vibration ball mill is 800-1200 times/min, and the ball milling time is 18-24 hours.

9. The method according to claim 8, wherein the vibratory ball milling treatment adopts ITO milling balls, and the ball-to-material ratio is 3-5: 1.

10. The method of claim 9, wherein the ITO grinding balls comprise large balls, medium balls, and small balls; the diameter of the big ball is 8-10 mm, the diameter of the middle ball is 5-8 mm, and the diameter of the small ball is 3-5 mm; the mass ratio of the big balls to the middle balls to the small balls is 1:1: 2.

Technical Field

The invention relates to the technical field of photoelectric material recycling, in particular to a method for recycling ITO powder from an ITO residual target/waste target.

Background

Indium Tin Oxide (ITO) films prepared from indium tin oxide as a raw material have the advantages of transparency to visible light, conductivity, high hardness, corrosion resistance and wear resistance, and are widely applied to industry in recent years. However, the utilization rate of the sputtering target is usually low, the utilization rate of the planar target is only about 30%, the utilization rate of the rotary target is high, but the utilization rate is only about 70%, because the raw material of the ITO target is mainly indium oxide, indium is a rare metal, the price is high, and the indium resource is a scarce resource, the recycling of the ITO target is particularly important.

At present, the recovery of the ITO waste target is roughly divided into two categories, one is wet recovery, the rough process flow of the method is to dissolve the ITO waste target by strong acid, and then high-purity indium, tin simple substance or indium-tin alloy is extracted through steps of electrolysis, hydrolysis precipitation, alkaline separation, replacement and the like, the method has the advantages of complex process, longer period, higher cost and serious energy resource consumption, and ITO powder cannot be directly obtained; the other method is to directly prepare the ITO waste target into ITO powder, and the method is a relatively energy-saving recovery method because the process of preparing indium powder into ITO powder is omitted. For example, in chinese patent CN104843771A, an ITO waste target is directly placed in a plasma reaction chamber, and the waste target is directly heated into ITO gas by high-temperature plasma, and then cooled into ITO powder; chinese patent CN105366709A, the ITO waste target is heated by electric arc generated by electrode discharge to form ITO gas, and then the gas is rapidly condensed into ITO powder; the two preparation methods are characterized in that waste targets are atomized and then solidified into ITO powder, the ITO powder can be directly used for preparing ITO targets, but the ITO waste targets belong to ceramic materials, and huge energy is needed for gasifying the waste targets, so that the two methods still have serious energy consumption, high production cost and expensive equipment.

Disclosure of Invention

In view of the above, the present invention is directed to a method for collecting ITO powder from an ITO residual target/waste target. The method provided by the invention processes the ITO residual target/waste target into ITO powder which can be directly used for preparing the ITO target material, and has the advantages of simple process, energy saving, environmental protection and low production cost, and is suitable for large-scale production.

In order to achieve the above object, the present invention provides the following technical solutions:

the invention provides a method for recovering ITO powder from an ITO residual target/waste target, which comprises the following steps:

(1) pickling the ITO residual target/waste target with a clean surface by using strong acid to obtain an indium-removing target material;

(2) heating and insulating the indium-removing target material under the condition of introducing oxygen, and then soaking the insulated target material into water for quenching to carry out thermal stress crushing to obtain ITO particles with the particle size of 5-10 mm;

(3) performing ring rolling crushing treatment on the ITO particles with the particle size of 5-10 mm to obtain ITO powder with the particle size of 0.5-1 mm;

(4) carrying out airflow crushing treatment on the ITO powder with the particle size of 0.5-1 mm, and screening to obtain ITO powder with the particle size of less than or equal to 5 micrometers;

(5) and carrying out vibration ball milling treatment on the ITO powder with the particle size of less than or equal to 5 microns to obtain the ITO powder with the particle size of 100-500 nm.

Preferably, the flow rate of the oxygen introduced in the step (2) is 100-120L/min; the heating and heat preservation temperature is 1200-1400 ℃, and the heat preservation time is 2-5 h.

Preferably, after the step (2) of performing thermal stress crushing, the method further comprises drying the ITO particles obtained by crushing after taking out the ITO particles from water.

Preferably, the ring roll milling crushing treatment in the step (3) is carried out in a vertical ring roll mill; the rotating speed of the main shaft of the vertical ring roller mill is 180-200 r/min.

Preferably, after the ring-roll milling crushing treatment in step (3), the method further comprises acid-washing the ITO powder obtained after crushing with strong acid.

Preferably, after the step (1) or the step (3) is acid-washed, the method independently further comprises sequentially performing ultrasonic washing and drying on the acid-washed ITO product; the ultrasonic cleaning adopts water as a cleaning agent.

Preferably, the airflow crushing treatment in the step (4) is performed in an impact airflow crusher; the impact plate of the impact type jet mill is an ITO plate.

Preferably, the vibratory ball milling treatment in the step (5) is carried out in a vibratory ball mill; the vibration frequency of the vibration ball mill is 800-1200 times/min, and the ball milling time is 18-24 hours.

Preferably, ITO grinding balls are adopted in the vibration ball milling treatment, and the ball-to-material ratio is 3-5: 1.

Preferably, the ITO grinding ball comprises a large ball, a middle ball and a small ball; the diameter of the big ball is 8-10 mm, the diameter of the middle ball is 5-8 mm, and the diameter of the small ball is 3-5 mm; the mass ratio of the big balls to the middle balls to the small balls is 1:1: 2.

The invention provides a method for recovering ITO powder from an ITO residual target/waste target, which comprises the steps of cleaning and acid washing the surface of the ITO residual target/waste target, carrying out thermal stress crushing treatment, carrying out ring roller grinding crushing treatment, carrying out airflow crushing treatment and carrying out vibration ball milling treatment, and processing the ITO residual target/waste target into ITO nano powder with the particle size of 100-500 nm. According to the invention, the ITO residual target/waste target is processed into ITO nano powder which can be directly used for preparing the ITO target material, a large number of links of metal separation and purification are not needed, and the process is simple, economic and environment-friendly; according to the invention, the ITO target does not need to be atomized in the process of preparing the ITO powder, so that the energy consumption and the equipment cost are reduced, and the energy-saving and environment-friendly effects are achieved. Therefore, the method provided by the invention processes the ITO residual target/waste target into ITO powder which can be directly used for preparing the ITO target material, and has the advantages of simple process, energy saving, environmental protection, low production cost and suitability for large-scale production.

In addition, the invention adopts aerobic heating and heat preservation in the stage of thermal stress crushing treatment, avoids the thermal decomposition of the ITO target in the heating process, and improves the purity of the ITO powder, and further, the ITO powder is pickled after the ring roller grinding treatment, the ITO plate is used as an impact plate in the process of airflow crushing treatment, and the ITO grinding balls are used in the process of vibration ball grinding treatment, thereby avoiding the pollution of the device to the powder in the refining process, and further improving the purity of the ITO powder. Therefore, the ITO powder recovered by the method provided by the invention has high purity which can reach 99.99%, and meanwhile, the recovery rate of the waste target is greatly improved and is more than 98%.

Drawings

FIG. 1 is a diagram showing a real object of an ITO residual target in example 1;

FIG. 2 is a physical diagram of an ITO particle after thermal stress crushing in example 1;

FIG. 3 is a diagram showing a natural stacking state of ITO powder after the ring-roller mill crushing treatment in example 1;

FIG. 4 is a scanning electron micrograph of ITO powder after jet milling in example 1;

FIG. 5 is a graph showing a distribution of particle sizes of ITO powder obtained after ball milling in example 1.

Detailed Description

The invention provides a method for recovering ITO powder from an ITO residual target/waste target, which comprises the following steps:

(1) pickling the ITO residual target/waste target with a clean surface by using strong acid to obtain an indium-removing target material;

(2) heating and insulating the indium-removing target material under the condition of introducing oxygen, and then soaking the insulated target material into water for quenching to carry out thermal stress crushing to obtain ITO particles with the particle size of 5-10 mm;

(3) performing ring rolling crushing treatment on the ITO particles with the particle size of 5-10 mm to obtain ITO powder with the particle size of 0.5-1 mm;

(4) carrying out airflow crushing treatment on the ITO powder with the particle size of 0.5-1 mm, and screening to obtain ITO powder with the particle size of less than or equal to 5 micrometers;

(5) and carrying out vibration ball milling treatment on the ITO powder with the particle size of less than or equal to 5 microns to obtain the ITO powder with the particle size of 100-500 nm.

According to the invention, the ITO residual target/waste target with a clean surface is subjected to acid washing by using strong acid, so as to obtain the indium-removed target material. The present invention has no particular requirement on the source of the ITO residual target/waste target, and the ITO residual target/waste target from which the present invention is known to those skilled in the art can be applied to the method of the present invention. In the present invention, the surface cleaning is specifically: and wiping off dust on the surface of the ITO residual target/waste target by using a cleaning cloth.

In the invention, the strong acid is preferably sulfuric acid with the mass concentration of 10-15%, and more preferably sulfuric acid with the mass concentration of 12-13%; according to the invention, indium simple substance generated in the sputtering process of the ITO residual target/waste target or indium simple substance residue used in the binding process is removed through acid washing, and the acid washing time is preferably 10-20 min. After acid washing, the invention also preferably carries out ultrasonic cleaning and drying on the ITO product after acid washing in sequence. In the invention, the cleaning agent adopted for ultrasonic cleaning is preferably water, and the water is preferably deionized water; the ultrasonic cleaning time is preferably 20-30 min; the invention removes the residual acid on the surface of the ITO product after the acid cleaning through ultrasonic cleaning. In the present invention, the temperature and time for the drying are not particularly required, and the moisture can be sufficiently removed.

After the indium-removing target material is obtained, the indium-removing target material is heated and insulated under the condition of introducing oxygen, then the insulated target material is immersed in water for quenching and thermal stress crushing, and ITO particles with the particle size of 5-10 mm are obtained. In the invention, the flow rate of the introduced oxygen is preferably 100-120L/min, and more preferably 110L/min. In the invention, the heat preservation temperature of the heating heat preservation is preferably 1200-1400 ℃, more preferably 1300 ℃, and the heat preservation time is preferably 2-5 h, more preferably 3-4 h. In the present invention, the heat retention is preferably performed in an atmospheric aerobic furnace. The invention adopts aerobic heating and heat preservation in the stage of thermal stress crushing treatment, avoids thermal decomposition of the ITO target material (the ITO target material is easy to lose oxygen and reduce into a metal simple substance at high temperature), and improves the purity of the ITO powder.

In the present invention, the water is preferably normal temperature deionized water; and (3) immersing the heat-insulated target material into water, and crushing the target material into ITO particles with the particle size of 5-10 mm due to thermal stress under the condition of high-temperature shock cooling. After the thermal stress crushing is carried out, the invention also preferably takes out the ITO particles obtained by crushing from water and then carries out drying; the present invention does not require any particular temperature or time for drying, and it is sufficient to remove moisture from the ITO particles.

After ITO particles with the particle size of 5-10 mm are obtained, the ITO particles with the particle size of 5-10 mm are subjected to ring roller grinding and crushing treatment to obtain ITO powder with the particle size of 0.5-1 mm. In the present invention, the ring roll mill crushing treatment is preferably performed in a vertical ring roll mill; the rotating speed of the main shaft of the vertical ring roller mill is 180-200 r/min, and more preferably 190 r/min. The invention has no special requirements on the vertical ring roller mill, and a vertical ring roller mill which is well known to a person skilled in the art can be adopted. ITO particles with the particle size of 5-10 mm are crushed into powder in the ring roller grinding and crushing treatment process, and the particle size is 0.5-1 mm.

After the ring-roll mill crushing treatment, the ITO powder obtained after crushing is preferably subjected to acid washing with a strong acid in the present invention. In the invention, the strong acid is preferably sulfuric acid with the mass concentration of 5-10%, and more preferably sulfuric acid with the mass concentration of 6-8%; the pickling time is preferably 10-20 min. According to the invention, the ITO powder obtained after crushing is subjected to acid washing, so that metal simple substances (mainly iron simple substances) generated by abrasion of the ring roller mill can be removed, and the purity of the prepared ITO powder is further improved. After the acid washing, the invention also preferably carries out ultrasonic cleaning and drying on the ITO product after the acid washing in sequence; the ultrasonic cleaning and drying conditions are the same as those in the above scheme, and are not described again here.

After the ITO powder with the particle size of 0.5-1 mm is obtained, the ITO powder with the particle size of 0.5-1 mm is subjected to airflow crushing treatment and then screened to obtain the ITO powder with the particle size of less than or equal to 5 microns. In the present invention, the air stream-crushing treatment is preferably performed in an impact type air stream crusher, and the present invention does not particularly require the configuration of the impact type air stream crusher, and an impact type air stream crusher having a configuration well known to those skilled in the art may be used. In the invention, the impact plate of the impact type jet mill is preferably an ITO plate, and the ITO plate is used as the impact plate, so that the pollution of a jet mill on powder is avoided, and the purity of the ITO powder is further improved.

In the present invention, the screening is preferably carried out by a screen machine, further pulverization and screening by the air current crushing treatment are carried out to obtain ITO powder having a particle size of 5 μm or less, and the screened ITO powder having a particle size of more than 5 μm is again subjected to the air current crushing treatment.

After the ITO powder with the particle size of less than or equal to 5 microns is obtained, the ITO powder with the particle size of less than or equal to 5 microns is subjected to vibration ball milling treatment, and the ITO powder with the particle size of 100-500 nm is obtained. In the present invention, the vibration ball milling treatment is preferably performed in a vibration ball mill, and the present invention does not particularly require the configuration of the vibration ball mill, and a vibration ball mill having a configuration well known to those skilled in the art may be used. In the invention, the excitation frequency of the vibration ball mill is preferably 800-1200 times/min, and more preferably 900-1100 times/min; the ball milling time is preferably 18-24 h, and more preferably 20-22 h.

In the invention, ITO grinding balls are preferably adopted in the vibration ball milling treatment, and the ball-to-material ratio is preferably 3-5: 1, and more preferably 4: 1; the ITO grinding ball preferably comprises a large ball, a middle ball and a small ball; the diameter of the large ball is preferably 8-10 mm, more preferably 9mm, the diameter of the middle ball is preferably 5-8 mm, more preferably 7mm, and the diameter of the small ball is preferably 3-5 mm, more preferably 4 mm; the mass ratio of the large balls, the medium balls and the small balls is preferably 1:1: 2. The large balls, the medium balls and the small balls are mixed to carry out vibration ball milling treatment on the ITO powder with the particle size of less than 5 mu m, so that the ball milling efficiency and the ball milling quality can be improved. The invention takes the ITO grinding ball as the grinding ball of the vibration ball mill, avoids the pollution of the vibration ball mill to the powder and further improves the purity of the ITO powder. And performing vibration ball milling treatment to obtain ITO powder with the particle size of 100-500 nm, and directly using the ITO powder for preparing the ITO target.

According to the invention, the ITO residual target/waste target is processed into ITO nano powder which can be directly used for preparing the ITO target material, a large number of links of metal separation and purification are not needed, and the process is simple, economic and environment-friendly; according to the invention, the ITO target does not need to be atomized in the process of preparing the ITO powder, so that the energy consumption and the equipment cost are reduced, and the energy-saving and environment-friendly effects are achieved. Therefore, the method provided by the invention has the advantages of simple process, energy conservation, environmental protection and low production cost, and is suitable for large-scale production; meanwhile, the purity of the recovered ITO powder is high and can reach 99.99%, the recovery rate of the waste target is greatly improved, and the recovery rate of the waste target is more than 98%.

The following will describe in detail the method for collecting ITO powder from ITO targets in the present invention with reference to examples, but they should not be construed as limiting the scope of the present invention.