KR100622106B1 - A manufacturing method of ito powder by a used ito target - Google Patents

Abstract

The present invention comprises the steps of: polishing the waste ITO target to obtain a powder; Drying and sieving the ITO powder obtained after the polishing; And a heat treatment to remove impurities from the dried and sifted ITO powder.

Unlike the conventional recycling methods, the manufacturing method does not separate and collect indium and tin separately, but as a completely new method for directly recovering ITO powder composed of indium oxide and tin oxide mixed at a predetermined ratio, and has a constant composition ratio. It is not necessary to make other process to make with ITO, which can simplify the production process and enable mass production industrially, and it is possible to obtain high quality ITO powder due to the small amount of impurities, and it is environmentally friendly because it does not use harmful substances such as strong acid. And economic effect.

ITO, Polishing, Diamond Wheel, Sieving, Heat Treatment, Sintering

Description

A manufacturing method of ITO powder by a used ITO target}

1 is a flow chart sequentially showing the manufacturing process of the present invention

Figure 2 is a graph showing the X-ray diffraction (XRD) results for the ITO powder prepared according to the present invention

Figure 3 is a photograph of the ITO powder of the present invention observed with a scanning electron microscope

Figure 4 is a photograph of the sintered body sintered the ITO powder of the present invention

The present invention relates to a method for producing ITO powder from waste indium tin oxide (ITO), and more specifically, to indium oxide and tin oxide without going through the process of separating indium and tin from the waste ITO target. It relates to a method for producing ITO powder composed of this ratio.

Generally, indium tin oxide (hereinafter referred to as “ITO”) is a material having conductivity and transparency, and is applied to various industrial fields such as liquid crystal display devices, plasma display panels, field emission display devices, and electroluminescent devices. It is becoming.

The thin film using ITO is manufactured by various thin film deposition methods, but mainly uses a sputtering method in which a substance is separated from an ITO target by atomic and molecular units and deposited on a substrate.

The ITO targets used in this way are steadily increasing in demand due to the rapid development of related industries. However, the efficiency of the above-mentioned targets is very low (30%) due to process reasons, and in particular, a large portion of expensive indium is used in the raw materials constituting the ITO targets. There was a problem of waste.

Therefore, in recent years, studies on recycling waste ITO targets have been actively conducted. As a result of this study, Japanese Patent Laid-Open Publication Nos. Hei 10-204673 and Hei 8-91838 have pulverized the waste ITO target and treated acid. Japanese Patent Laid-Open Publication No. 7-145432 and U.S. Patent No. 5,543,031 disclose a method of dissolving indium oxide and dissolving only indium oxide, and collecting and separating tin oxide and indium oxide through electrolysis.

However, the above-mentioned recycling methods mostly collect tin or indium separately and thus require another process of manufacturing ITO having a constant composition ratio later, and most of them are performed at a laboratory scale, which is unsuitable for industrial mass production. In particular, the dissolution of waste ITO using a large amount of strong acid was environmentally unsuitable and dangerous.

Therefore, the present invention is to solve the above problems, unlike the conventional methods can recover the ITO powder consisting of a mixture of indium oxide and tin oxide in a certain ratio without separating the indium and tin from the waste ITO target separately. It is an object of the present invention to provide a method for preparing ITO powder from an entirely new waste ITO target.

Another object of the present invention is to provide a method for producing a sintered body by molding and sintering the ITO powder obtained by the above production method.

The present invention to achieve the above object,

Polishing the waste ITO target to obtain a powder;

Drying and sieving the ITO powder obtained after the polishing;

Heat treatment to remove impurities from the dried and sieved ITO powder; is achieved by providing a method for producing ITO powder from the waste ITO target, characterized in that consisting of.

Hereinafter, the manufacturing method of the present invention will be described in more detail.

1 is a flow chart sequentially showing the manufacturing process of the present invention, as shown in the manufacturing method of the present invention comprises the steps of polishing the waste ITO target; Drying the ITO powder obtained through the polishing; And heat-treating the dried ITO powder.

First, by polishing the waste ITO targets collected from the end-of-life liquid crystal display device, the plasma display panel, the field emission display device, and the electroluminescent device using a polishing machine, ITO powder separated from the waste target surface can be acquired.

In order to achieve the refinement of the ITO powder thus obtained, it is preferable to use a wheel made of fine diamond, and more preferably, a diamond wheel having a size of 35 μm is used as the polishing machine.

In the polishing process as described above, for smooth polishing and smooth flow of the powder, ultra-pure water (DI-water) is continuously injected into the wheel surface during polishing, and the ITO powder is obtained in the ultrapure water.

As such, the ITO powder contained in the ultrapure water after grinding is obtained by using a solid-liquid separator or immediately in the drying process, and then sieved to filter out powders of less than a certain size. The mesh of the sieve used in the above is not particularly limited because it is changed fluidly by the user, it is preferable to use a sieve of 100 to 400 mesh.

In addition, if the micron of the dried ITO powder as described above, in particular, if the nano-size powder is desired, the step of pulverizing through a grinder may be added. However, the grinding step may be performed after the heat treatment, which is the next step.

As such, the ITO powder filtered through drying and sieving is subjected to heat treatment to remove diamond particles that can only penetrate during polishing as impurities, and the heat treatment temperature is made at 800 to 1500 ° C. at which diamond can be removed. Preferably, the time may vary depending on the amount to be treated but is carried out for approximately 0.5-6 hours.

Unlike the conventional recycling methods, the method for producing ITO powder from the waste ITO target of the present invention having the above-described steps consists of mixing indium oxide and tin oxide in a predetermined ratio without collecting indium and tin separately. It is a completely new way to recover ITO powder immediately.

Therefore, the present invention does not require any other process for producing tin and indium from ITO having a certain composition ratio, which simplifies the production process and enables industrial mass production, and also obtains high quality ITO powder due to less impurities. It is eco-friendly because it does not use harmful substances such as strong acid.

In addition, the present invention is to provide a method for producing a sintered body by molding and sintering the ITO powder obtained through the manufacturing method.

To this end, the method comprises the steps of filling and pressing the ITO powder heat-treated in the last process in the above-mentioned recycling method into a molding machine; Sintering the molded ITO molded body; further comprises. The sintering step is carried out in the same manner as the heat treatment step described above.

However, since the heat treatment and sintering step in the process of manufacturing the sintered body is carried out at the same temperature range, it can be carried out at the same time. Therefore, the ITO powder obtained by grinding in the aforementioned recycling method is dried and sieved, and then molded in a molding machine. The sintered body can be manufactured by directly undergoing heat treatment and sintering.

Hereinafter, the present invention will be described in more detail with reference to the following examples, which are only presented to aid the understanding of the present invention, and the present invention is not limited to the following examples.

<Example 1>

The collected waste ITO targets were polished using a polisher equipped with a 35 μm diamond wheel, and during the polishing, DI-water was continuously injected into the wheel surface, which was removed from the waste target surface. The ITO powder was allowed to be contained in ultra pure water.

As such, the waste target was ground and the ITO powder mixed with the ultrapure water was collected, dried until the ultrapure water was completely evaporated in the oven, and then filtered through the sieve using a 100 mesh sieve. In addition, the ITO fine powder was heat-treated at 1000 ° C. for 1 hour in a heater.

The heat treated ITO powder was pressed and molded in a molding machine, and then the adult was sintered at 1000 ° C. for 1 hour in a heater and then cooled to room temperature. The sintered density of the prepared sintered compact was 4.49 g / cm 3 and the relative density was 62%.

Figure 2 is a graph showing the X-ray diffraction (XRD) results for the ITO powder of the present invention, X-ray diffraction (XRD) analysis of the ITO powder obtained after the heat treatment as a result of the presence of other phases do not appear to be impurities It could be confirmed that there was no.

Figure 3 is a photograph of the ITO powder of the present invention observed with a scanning electron microscope, it can be seen that the size of the ITO powder particles obtained after the heat treatment as shown in this shows a size of approximately 0.5 ~ 3㎛.

Figure 4 is a photograph of the sintered body sintered sintered ITO powder of the present invention, as shown there was no particular problem in the molding process, heat treatment and sintering process, the shape was also good.

<Example 2>

To prepare a heat-treated ITO powder in the same manner as in Example 1, in order to nanonize the size of the powder, the powder obtained through the polishing process was dried and then subjected to an Attrition milling process.

At this time, the attrition jar (Jar), the blade (Blade), and the ball (Ball) used a zirconia material in order to prevent the incorporation of impurities. Milling was performed using methanol as a solvent, and the rotation speed was 300 rpm for 15 hours. lost.

As a result of the attrition milling, drying and sieving were carried out again. BET analysis was performed to analyze the particle size of the powder. The measured specific surface area was 25.67 cm 2 / g, and the particle size was 33 nm.

As described above, the method for producing ITO powder from the waste ITO target of the present invention, unlike conventional recycling methods, is not separately collected from indium and tin, but instead of collecting indium oxide and tin oxide in a predetermined ratio. It is a completely new way to recover the wastewater, and it does not need any other process to make ITO with a certain composition ratio, which simplifies the production process, enables mass production industrially, and obtains high quality ITO powder due to the small amount of impurities. It does not use harmful substances such as strong acid, so it is environmentally friendly and economical.

Claims (7)

Polishing the waste ITO target to obtain a powder; Drying and sieving the ITO powder obtained after the polishing; Heat treating to remove impurities from the dried and sieved ITO powder. The method of claim 1, wherein the polishing is performed using a diamond wheel having a size of 35 μm. The method according to claim 1 or 2, characterized in that a continuous injection of ultra-water (DI-water) to the wheel surface during the polishing. 4. The method of claim 3, further comprising a grinding step for refining the polished ITO powder to nano size. The method of claim 4, wherein the heat treatment is performed at 800 to 1500 ° C. for 0.5 to 6 hours. A method for producing an ITO sintered compact, characterized in that the ITO powder prepared by the manufacturing method of claim 1 is filled into a molding machine, pressed, and then molded, and then the molded ITO molded body is sintered under the same conditions as heat treatment. A method for manufacturing an ITO sintered compact, characterized in that the molding and filling is performed before the heat treatment of the ITO powder obtained by the method of claim 1, followed by simultaneous heat treatment and sintering.

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