KR101383280B1 - Method of collecting gallium from igzo target - Google Patents

Abstract

The present invention relates to a method of retrieving gallium from an IGZO target, which includes the steps: a) preparing a leach solution for IGZO; b) introducing a pH control agent into the leach solution to separate a sediment containing gallium ions from the leach solution; c) putting the sediment into a basic solution to prepare an electrolyte; d) applying electricity to the electrolyte to extract metal containing gallium from the electrolyte; and e) removing zinc by vacuum-refining the metal. According to the method of retrieving gallium from the IGZO target of the present invention, only gallium can be effectively extracted from the IGZO included in a solar cell or an OLED waste, so that the circulation of gallium, which is a rare metal, can be significantly increased. In addition, the purity of retrieved gallium is at least 99.9%, so that high-purity gallium product can be produced. The high-purity gallium product is eco-friendly in that the wasted IGZO target is used as a source material, and the rare resources can be recycled. [Reference numerals] (AA) Prepare a leach solution.; (BB) Introduce zinc.; (CC) Introduce a pH control agent.; (DD) Introduce a basic solution; (EE) Collect electrolyte.; (FF) Vacuum refining.; (GG) Gallium.; (HH) Retrieve indium.; (II) Collect gallium hydroxide.; (JJ) Collect zinc.

Description

Method of collecting gallium from indium gallium zinc oxide target {Method of collecting gallium from IGZO target}

The present invention relates to a method for recovering gallium from indium gallium zinc oxide (IGZO).

BACKGROUND ART [0002] Semiconductor devices used in ultra thin film transistor liquid crystal displays (TFT-LCDs) and organic light emitting diodes (OLED) are classified into amorphous silicon (a-si) Low-temperature polysilicon (p-si), and calcium selenide (CdSe). The most commonly used is amorphous silicon.

Amorphous silicon has the advantage of being used in various fields due to its high degree of freedom in the manufacturing process, but it is slow in driving speed (about 0.5 cm / V · sec) and the atomic arrangement is not regular. When the thin film is grown, So that carrier recombination acts as a serious defect. In order to solve this problem, amorphous silicon of a-Si: H type which removes defects by hydrogen atoms is also used, but the defect has not been completely solved yet.

 In addition, low-temperature polysilicon has a completely aligned atomic structure, which is converted to a poly-Si form by irradiating amorphous silicon to a polysilicon film at the time of forming a semiconductor film, which has a faster driving speed than amorphous silicon (about 50 to 100 cm / V · sec), it is difficult to purify the gas and the process cost is high.

Recently, researches on semiconductors in the form of metal oxides have been actively conducted to solve the disadvantages of silicon-based semiconductors. In particular, indium gallium zinc oxide (IGZO) semiconductors can be used in various semiconductor devices in displays. It is known.

IGZO has a charge driving speed of about 7 ㎝ / V · sec, which is lower than p-Si, but about 15 times faster than a-Si, and has a large area by applying the sputtering method used for conventional transparent electrodes when manufacturing as a target. It is easy to use and inexpensive to process cost, making it a popular next-generation semiconductor material.

IGZO studied from metal oxide semiconductors contains indium, gallium and zinc. Gallium (Ga) is contained in semiconductors, solar cells, LEDs, can store hydrogen, and is also used in Ryu Trio research. However, the production volume is not so high compared to the required quantity, and the price is high, and since the supply of the waste has started recently and the recovery technology from the waste has not yet been established, the recovery amount is very low.

Korean Patent Laid-Open Publication No. 10-2004-0096668, 10-1989-0014387 and the like describe a method for recovering gallium from a sphalerite containing gallium, or recovering gallium chloride from a compound containing gallium. However, the above techniques are extracted from raw materials containing gallium or extracted with chloride of gallium, and there is no research on how to recover gallium from the semiconductor composition.

Republic of Korea Patent Publication 10-2004-0096668 (November 17, 2004) Republic of Korea Patent Application Publication No. 10-1989-0014387 (October 23, 1989)

In order to solve the above problems, the present invention is to prepare a leaching solution containing a IGZO target containing gallium, and to provide a gallium recovery method that can recover only gallium by effectively separating indium and zinc from the leaching solution. do.

In addition, an object of the present invention is to provide a gallium recovery method that can increase the purity of gallium recovered through electrolytic extraction and vacuum electrolysis during the process.

The present invention relates to a method for recovering gallium from an IGZO target.

One aspect of the present invention is

a) preparing an indium gallium zinc oxide target leachate;

b) adding a pH adjusting agent to the leachate, separating the leachate and the precipitate containing gallium ions;

c) preparing an electrolyte by adding the precipitate to a basic solution;

d) electrically applying said electrolyte to separate metals containing gallium; And

e) vacuum purifying the metal to remove zinc;

It relates to a gallium recovery method from the indium gallium zinc oxide target containing.

In one aspect of the present invention,

a) preparing an leachate by adding an indium gallium zinc oxide target to an acidic solution;

b) recovering indium by further adding and substituting zinc in the leaching solution;

c) recovering the gallium hydroxide by adding a pH adjusting agent to the leaching solution of step b) and separating the leaching solution from the precipitate;

d) adding the precipitate to a basic solution to prepare an electrolyte solution;

e) electrolytically collecting the electrolyte to separate gallium-zinc metal from the electrolyte; And

f) vacuum purifying the gallium-zinc metal to remove zinc;

It relates to a gallium recovery method from the indium gallium zinc oxide target containing.

At this time, the leaching solution of step a) is characterized in that the content ratio of 1: 3 to 5 weight ratio of the indium gallium zinc oxide target and acid, and b) the step leaching solution is diluted by adding 1 to 1 to 3 weight ratio of water to the leaching solution It features.

In addition, the step b) is characterized in that the zinc is added 1 to 2 times more indium content.

In addition, the step c) is characterized in that the pH adjusting agent is added so that the pH of the leaching solution is 4 to 5.

In addition, the step d) is characterized in that the concentration of the basic solution is 3 to 10 M.

Also, the electrolytic harvesting in step e) is performed using an insoluble electrode plate under a current density of 400 to 1,000 A / m < 3 >.

In addition, the vacuum purification of step f) is characterized in that proceeding by applying a temperature of 800 to 900 ℃ at a pressure of 10 ^-2 to 10 ^-3 mmHg.

The method for recovering gallium from the IGZO target according to the present invention can effectively extract only gallium from IGZO contained in solar cells and OLED wastes, which can greatly increase the circulation of gallium, a rare metal. The purity of recovered gallium is 99.9% or more and can be produced as a high-purity gallium product. In addition, it is environmentally friendly in terms of using IGZO targets discarded as raw materials, and has the advantage of recycling rare resources.

FIG. 1 is a flowchart illustrating a gallium recovery method according to the present invention.

Hereinafter, a method for recovering gallium from the IGZO target according to the present invention will be described in detail.

The method for recovering gallium from the IGZO target according to the present invention

a) preparing an indium gallium zinc oxide target leachate;

b) adding a pH adjusting agent to the leachate, separating the leachate and the precipitate containing gallium ions;

c) preparing an electrolyte by adding the precipitate to a basic solution;

d) electrically applying said electrolyte to separate metals containing gallium; And

e) vacuum purifying the metal to remove zinc;

To include more specifically,

a) preparing an leachate by adding an indium gallium zinc oxide target to an acidic solution;

b) recovering indium by further adding and substituting zinc in the leaching solution;

c) recovering the gallium hydroxide by adding a pH adjusting agent to the leaching solution of step b) and separating the leaching solution from the precipitate;

d) adding the precipitate to a basic solution to prepare an electrolyte solution;

e) electrolytically collecting the electrolyte to separate gallium-zinc metal from the electrolyte; And

f) vacuum purifying the gallium-zinc metal to remove zinc;

. ≪ / RTI >

Hereinafter, the gallium recovery method according to the present invention will be described in detail in each step.

Step a) is a step of preparing a leachate by adding the IGZO target to the acidic solution.

The IGZO target is preferably pulverized into fine particles at a predetermined size before the acidic solution. More specifically, conventionally used fine particle production method, it is preferable to grind the IGZO target using ball milling and then add the acidic solution.

In the case of using a ball milling machine, it is preferable to use balls of ceramic material such as alumina and zirconia having high hardness, which are used for ball milling. The balls may be all the same size, It can also be used. The size of the ball, the milling time, and the rotation speed per minute of the ball miller can be adjusted to the target particle size, and the powder can be pulverized into fine particles of 0.1 to 1 mm through two pulverizing processes. However, since the particles of the IGZO target may be agglomerated, the IGZO target having 0.1 to 1 mm size particles may be selectively separated and used by sieving the particles having a predetermined size or more. However, in the present invention, any pulverization method capable of pulverizing the IGZO target to obtain fine particles can be used without limitation.

In addition, in the present invention, it is preferable to use the IGZO target as fine particles of 0.1 to 1 mm, but is not limited thereto.

The acid solution may be pure acid or diluted acid. For example, it is preferable to use one or more acids selected from hydrochloric acid, nitric acid and sulfuric acid. It is preferable to select the acid in consideration of the subsequent steps, and it is most preferable to use hydrochloric acid.

In the acidic solution, the content ratio of the IGZO target and the acid is preferably 1: 3 to 5 weight ratio (weight percentage). If the acid content ratio is less than 3 weight ratio, the IGZO target will not be completely dissolved. If it is more than 5 weight ratio, a large amount of dilution water may be used before the substitution reaction with zinc.

In step a), the IGZO target is added to an acidic solution, and then heated to a temperature of 60 to 90 ° C., and then dissolved for 24 to 48 hours to prepare a leaching solution. However, it is not limited to the above temperature and time.

When the leaching solution is prepared, indium may be recovered by further adding zinc to the leaching solution prepared as in step b). However, before adding zinc, the leachate must be diluted by adding water.

In the step b), the amount of water to be added is preferably 1: 1 to 3 by weight relative to the leached liquid. When the water content ratio is less than 1 weight ratio, zinc used for substitution may be leached. If the weight ratio is more than 3 weight ratio, the substitution reaction may not proceed smoothly.

Zinc is added directly to the leachate diluted with water. The zinc is introduced to replace indium in the leaching liquid due to the ionization tendency, and may be fine or bulk regardless of particle size.

The amount of zinc added in step b) is 1 to 2 times the indium content. If the addition amount is out of the indium in the leaching solution is not completely substituted or a large amount of zinc is present in the leaching solution after the completion of the substitution reaction. After adding zinc, the temperature of the leachate was adjusted to 40 to 60 ° C. and a substitution reaction was induced for 12 to 24 hours.

Step c) is a step of precipitating and separating the gallium hydroxide by adding a pH adjusting agent to the leaching liquid recovered indium.

PH adjusting agent according to the present invention is to induce a neutralization reaction so that the pH of the leaching solution is 4 to 5, preferably 4 to 4.5, for example, ammonium hydroxide, sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, hydroxide Any one or two or more aqueous solutions selected from magnesium, hydroxylamine, monoethanolamine, diethanolamine, and triethanolamine may be used, and are not limited as long as they are alkaline hydroxides capable of converting indium and zinc present in the leachate into hydroxides. Can be used without

After the reaction, the formed precipitated gallium-zinc hydroxide and the leachate are separated, and the separated gallium-zinc hydroxide is dried. However, since the leachate containing zinc remains in the hydroxide separated from the leachate, it is preferable to wash with water and then dry it.

Next, the recovered gallium-zinc hydroxide is added to the basic solution in step d) to prepare an electrolyte solution.

The basic solution is for dissolving the gallium-zinc hydroxide recovered in step c), for example ammonium hydroxide, sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, magnesium hydroxide, hydroxylamine, monoethanolamine, diethanol Any one or two or more aqueous solution selected from amine and triethanolamine may be used, and the same alkaline hydroxide aqueous solution as the pH adjuster of step c) may be used. However, it is preferable to use an aqueous sodium hydroxide solution of 3 to 10 M, preferably 5 to 8 M, for alkali leaching of gallium-zinc hydroxide, and below 5 M, gallium hydroxide may not be completely leached, and if more than 10 M, sodium hydroxide is completely dissolved. It does not reduce the reactivity in step e). The amount of gallium-zinc hydroxide added is preferably 100 to 200 g per 1 L of the aqueous alkali hydroxide solution.

The step d) is preferably carried out at a temperature of 60 to 90 캜 for 24 to 48 hours, since the hydroxide can be left as a residue and dissolved.

When the electrolyte is prepared, the gallium-zinc metal is recovered by electrolytic collection through step e).

In the present invention, the electrolytic extraction refers to extracting a target metal by an electrochemical method using a leaching solution as an electrolyte after leaching the target metal contained in trace amounts in the ore in an appropriate solvent. In the present invention, the target metal means gallium-zinc. .

The electrolytic harvesting can be used regardless of the kind of the metal if it is an insoluble electrode plate, and mainly SUS can be used. However, since polarization which interferes with the progress of electrolysis may be generated in a large amount, a small amount of tin, strontium, silver, It is preferable to use an electrode. It is also preferable to use a different kind of metal for the cathode and the anode.

The electrolytic collection may be performed by supplying a positive electrode and a negative electrode to the electrolyte prepared in step d) and supplying a current from a power source connected to the positive electrode and the negative electrode. At this time, the current density is preferably 400 to 1000 A / m 2, and the pH of the electrolyte is preferably 10 to 14, preferably 12 to 13, since the progress of electrolysis may be easy. In addition, if the current density is out, only hydrogen is discharged during electrolysis and gallium-zinc, which is a target metal, does not precipitate at all, so it is preferable to keep the above range.

When the gallium-zinc metal is precipitated through the step e), vacuum purification is performed to separate the gallium-zinc metal from the electrolyte and to remove zinc.

In the present invention, vacuum purification is a method of increasing the purity of a metal by separating any substance by using a difference in vapor pressure of each metal in a solid metal in which two or more metals are mixed. In the present invention, zinc remaining in the gallium-zinc metal is The vapor pressure is very high compared to gallium and can be easily removed at low pressure.

In the present invention, vacuum purification may use a sublimation purifier commonly used in the art, the degree of vacuum is 10 ^-2 to 10 ^-3 mmHg, the temperature is preferably carried out at 800 to 900 ℃. If the temperature is below 800 ° C, the removal of zinc is not complete, and at temperatures above 900 ° C, gallium loss occurs, which is undesirable.

Hereinafter, the gallium recovery method according to the present invention will be described in more detail with reference to examples. However, the following examples are only illustrative of the present invention, and the present invention is not limited by the following examples.

The method for measuring the physical properties of the examples according to the present invention is as follows.

(density)

The concentration of metal ions was measured using ICP (inductively coupled plasma, optima 7300, Perkin Elmer).

(water)

Purity was measured using ICP (inductively coupled plasma, optima 7300, Perkin Elmer).

(IGZO)

The components of the IGZO targets used in Examples and Comparative Examples are shown in Table 1.

[Table 1]

(Example)

① Leaching process: The IGZO target of Table 1 was grind | pulverized into 0.5 mm fine particle using the ball milling machine. An aqueous hydrochloric acid solution was prepared by setting the weight ratio of the crushed IGZO target and hydrochloric acid to 1: 3, and the IGZO target was added to an aqueous hydrochloric acid solution and leached at 70 ° C for 24 hours.

② Replacement process: The leached solution was diluted by adding water to make the weight ratio of the leached solution and water 1: 1, and the temperature of the leaching solution was adjusted to 50 ° C. Then, 250 g of zinc powder having an average particle diameter of 500 µm was added to the leaching solution, and indium metal was substituted for recovery.

③ Neutralization Precipitation Process: After recovery of indium metal, 1,500 g of sodium hydroxide was added and the pH was adjusted to 4.5 to prepare gallium-zinc hydroxide.

④ Alkaline leaching process: The prepared gallium-zinc hydroxide was added to 150 g of 7M sodium hydroxide aqueous solution and leached at 70 ° C. for 24 hours to prepare an electrolyte solution.

⑤ Electrolytic picking process: The gallium-zinc metal was recovered by putting the stainless steel electrode plate and setting the current density to 500 A / ㎡.

⑥ Vacuum purification process: The recovered gallium-zinc metal was charged to a tubular vacuum furnace and purified at 900 ° C. for 10 hours at a vacuum degree of 10 ⁻² mmHg to finally obtain gallium metal.

The purity of the finally obtained gallium metal and the metal ion concentration in each step were measured through the above process and are shown in Table 2 below.

(Comparative Example 1)

Gallium metal was obtained in the same manner as in Example 1, except that the zinc powder was not added in Example 1. The purity of the finally obtained gallium metal and the metal ion concentration in each step were measured and shown in Table 2 below.

(Comparative Example 2)

Gallium metal was obtained in the same manner as in Example 1, except that sodium hydroxide was added at 2,000 g in the neutralization precipitation step to pH 5.5. The purity of the finally obtained gallium metal and the metal ion concentration in each step were measured and shown in Table 2 below.

[Table 2]

Claims (8)

a) preparing an indium gallium zinc oxide target leachate;
b) adding a pH adjusting agent to the leachate to separate the leachate and the precipitate containing gallium;
c) preparing an electrolyte by adding the precipitate to a basic solution;
d) electrically applying said electrolyte to separate metals containing gallium; And
e) vacuum purifying the metal to remove zinc;
Gallium recovery method from the indium gallium zinc oxide target comprising a. The method of claim 1,
The leaching solution of step a) is a method for recovering gallium from an indium gallium zinc oxide target having a content ratio of 1: 3 to 5 by weight of an indium gallium zinc oxide target. The method of claim 1,
The b) step leaching solution is gallium recovery from the indium gallium zinc oxide target is diluted by adding a water 1: 1 to 3 weight ratio to the leaching solution. The method of claim 1,
B) recovering gallium from the indium gallium zinc oxide target by adding zinc to the leaching solution in step 1 to 2 times the amount of indium. The method of claim 1,
Step b) is a method of recovering gallium from the indium gallium zinc oxide target to add a pH adjuster so that the pH of the leaching solution is 4 to 5. The method of claim 1,
The basic solution of step c) has a concentration of 3 to 10M gallium recovery method from the indium gallium zinc oxide target. The method of claim 1,
In step d), an insoluble electrode plate is used, and a gallium recovery method from an indium gallium zinc oxide target having a current density of 400 to 1,000 A / m 3. The method of claim 1,
The step e) is a method for recovering gallium from the indium gallium zinc oxide target to apply a temperature of 800 to 900 ℃ at a pressure of 10 ^-2 to 10 ^-3 mmHg.

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