KR20170009142A - Method for leaching gallium and indium from mocvd dust - Google Patents

Abstract

The present invention relates to a method to leach Ga and In from MOCVD dust and, more specifically, relates to a method capable of leaching high-purity gallium and indium at a higher recovery rate than an existing recycling process by effectively recovering Ga and In from the MOCVD dust discharged without participating in an MOCVD reaction. The present invention comprises: a step of mixing MOCVD dust with at least one type of a chemical solvent; and a step of stirring the mixed solution at 100-600 rpm for 10-200 minutes.

Description

METHOD FOR LEAKING GALLIUM AND INDIUM FROM MOCVD DUST.

The present invention relates to a method of leaching gallium and indium from a metalorganic chemical vapor deposition dust (MOCVD dust), which is a by-product of an LED process, and more particularly, to a method of leaching gallium and indium from a MOCVD dust, And In to effectively recover gallium and indium with high purity at a higher recovery rate than the conventional recycling process.

Gallium (Ga) and indium (In) are used as core materials in various electronic industries such as semiconductors, displays, and solar cells due to their inherent electrical and optical properties. In particular, GaN / InGaN structures are being used for light emitting diodes (LEDs), which are rapidly growing in the industry, and the usage of gallium and indium is increasing. However, the production of gallium and indium, which is a by-product of zinc and bauxite, is very low at hundreds of tons per year. World production of gallium in 2012 was 273 tons, down 7% from the previous year. Indium produced 670 tons in 2012, similar to the previous year. Thus, to meet the demand for gallium and indium, worldwide attention has been focused on matching the supply of two metals through recycling.

In Korea, research and commercialization of indium recycling from waste has progressed considerably (HS Hong, et al., Res. Chem . Intermed . , 36 (2010) 761, RKI Kim, et al., Clean Technology , 19 (2013) 388.), and the recycling technology of gallium is very insufficient, so there is no commercially available plant.

On the other hand, Ga used for LED exists in the form of GaN. GaN is known as a substance which does not leach from acid and base, and the LED industry is also suffering from a wet etching process. However, it is urgent to develop recycling technology for the wastes generated from the LED industry because it contains a large amount of Ga. In particular, trimethylgallium and trimethylindium, which are raw materials used for GaN / InGaN growth through MOCVD, account for only about 10% of the layer formation and more than 90% of the trimethylindium is discharged to the outside.

On the other hand, with respect to the recycling of gallium and indium, a technique of recovering gallium by pyrolyzing gallium-containing scrap in a high frequency electric induction furnace (Patent Document 10-1999-0025109) and a solar cell scrap A technology for recovering indium and gallium by leaching and solvent extraction of a substance containing indium and gallium (USPN 8834818) has been proposed.

However, there is no conventional technology related to a method of leaching Ga and In from a MOCVD dust, which is a by-product of the LED process, to recycle the Ga and In, and it is known that a technique of recovering and recycling Ga or In through a dry / wet process from waste resources is known .

Accordingly, the present inventors continued research on a method for recovering gallium and indium from MOCVD dust discharged without participating in the MOCVD reaction. As a result, it was found that the high-purity gallium and indium were leached out from the MOCVD dust as a raw material at a high recovery rate The present invention has been completed.

Korean Patent Publication No. 10-1999-0025109

 H. S. Hong, et al., Res. Chem. Intermed., 36 (2010) 761  R. K. I. Kim, et al. Clean Technology, 19 (2013) 388.

Accordingly, an object of the present invention is to provide a method of effectively leaching Ga and In from MOCVD dust discharged without participating in a MOCVD reaction.

In order to accomplish the above object, the present invention provides a method of manufacturing a semiconductor device, comprising the steps of: 1) MOCVD dust is washed with at least one solvent selected from the group consisting of hydrochloric acid (HCl), nitric acid (HNO ₃ ), sulfuric acid (H ₂ SO ₄ ) and sodium hydroxide Mixing; 2) stirring the mixed solution at a speed of 100 to 600 rpm for 10 to 200 minutes; And 3) filtering the stirred mixed liquor to obtain an extract, and recovering gallium or indium from the leach liquor. The present invention also provides a method of leaching gallium, indium or gallium and indium from MOCVD dust.

The method according to the present invention can effectively recover and reuse Ga and In from MOCVD dust, which is an industrial waste discharged and discharged without participating in the MOCVD reaction, and can obtain gallium and indium of high purity at a higher recovery rate than the conventional recycling process There is an advantage.

1 is a photograph of a MOCVD dust used in the present invention.
FIG. 2 shows the results of X-ray rotation analysis of MOCVD dust.
Fig. 3 shows the ICP-AES analysis results of the leach solutions of Examples 4 to 23 measured in Experimental Example 3. Fig.
4 shows the results of analysis of the gallium content of the leach solution of Example 15 and Examples 24 to 26 measured in Experimental Example 4. FIG.
5 shows the results of analysis of the indium content of the leach liquor of Example 15 and Examples 24 to 26 measured in Experimental Example 4. Fig.

Hereinafter, the present invention will be described more specifically.

The present invention includes the steps of mixing with 1) an acid MOCVD dust (HCl), nitric acid (HNO _3), sulfuric acid (H ₂ SO ₄₎ and at least one solvent selected from the group consisting of sodium hydroxide (NaOH); 2) stirring the mixed solution at a speed of 100 to 600 rpm for 10 to 200 minutes; And 3) filtering the stirred mixed liquor to obtain an extract, and recovering gallium or indium from the leach liquor. The present invention also provides a method of leaching gallium, indium or gallium and indium from MOCVD dust.

Step 1: Preparation of mixed liquid

The first step of the method according to the present invention is a step of mixing a MOCVD dust and a solvent to obtain a mixed solution.

The MOCVD dust is a black fine powder generated during the MOCVD process in the fabrication of an LED, for example, a by-product containing gallium and indium, which does not participate in the formation of a GaN / InGaN layer among raw materials used for GaN / InGaN growth through MOCVD it means. If containing gallium and indium, which occurs during the MOCVD deoseuteueun LED manufacturing process is not particularly limited, preferably the hexagonal Ga _{0. 97} N _{0 . 9} O _{0 .09} (JCPDS No. 32-0398), hexagonal GaN (H-GAN, JCPDS No. 89-7522) and cubic GaN (C-GaN, JCPDS No. 52-0791).

The solvent of gallium and / or long as indium can be dissolved is not particularly limited, preferably the hydrochloric acid (HCl), nitric acid (HNO _3), sulfuric acid (H ₂ SO _4), and the group consisting of sodium hydroxide (NaOH) And may include one or more species.

The concentration of the solvent may be 1.5 to 6 M or 2 to 4 M.

The mixing ratio of the solvent and the MOCVD dust is not particularly limited as long as it can dissolve the gallium and / or indium contained in the MOCVD dust, but it is preferable to mix the MOCVD dust of 1 to 5 g with respect to 100 ml of the solvent.

Step 2: Stirring  And reaction step

Step 2 of the process according to the invention is a step of stirring the mixture.

The agitation is not particularly limited as long as it is a speed, a temperature, and / or a time used for leaching, but may be preferably performed at a rate of 100 to 600 rpm at 40 to 140 ° C for 10 to 200 minutes, Can be carried out at a temperature of 70 to 120 DEG C for 20 to 160 minutes at a rate of 300 to 500 rpm.

Step 3: Filtration step

Step 3 of the process according to the invention is a step of filtering the reacted mixed liquor to obtain an extract.

The filtration is not particularly limited as long as the filtration can be carried out in order to separate the solution and the undissolved impurities from the solution to obtain a solution, and filtration using a filter paper, centrifugation and the like can be used.

The leach liquor may comprise 4,500 to 6,500 ppm of gallium and 900 to 4,500 ppm of indium.

According to an embodiment of the present invention, the MOCVD dust used in the method according to the present invention may be heat-treated at 700-1,000 ° C. for 1 to 5 hours in air.

According to another embodiment of the present invention, the MOCVD dust and the Na ₂ CO ₃ may be mixed at a weight ratio of 1: 0.5 ~ 2 before the heat treatment of the MOCVD dust, and then the heat treatment may be performed.

As described above, when the MOCVD dust and the Na ₂ CO ₃ are mixed and heat-treated, the gallium contained in the MOCVD dust can be leached more than the non-annealed MOCVD dust. Accordingly, the leached solution leached by the leaching method further including the step of heat-treating the MOCVD dust mixed with Na ₂ CO ₃ as described above may contain 8,000 to 9,100 ppm of gallium and 40 to 200 ppm of indium.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the following examples are intended to illustrate the present invention, but the scope of the present invention is not limited thereto.

[ Example ]

Experimental Example  1. MOCVD dust analysis

The MOCVD dust is in the form of a fairly fine black powder, as shown in Figure 1, and is known to have good scattering properties in air.

X-ray diffraction analysis was carried out using an X-ray diffraction (Shimadzu XRD-6100) to analyze the crystal phase of the MOCVD dust, and an ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometer, Perkin Elmer Optima-4300 DV). The results of the X-ray diffraction analysis are shown in FIG. 2, and the results of ICP-AES analysis are shown in Table 1 below.

As can be seen in FIG. 2, the MOCVD dust is composed of hexagonal Ga _{0 . 97} N _{0 . 9} O _{0 .09} been identified as the (JCPDS No. 32-0398), when considering that the peak overlapping hexagonal GaN (H-GAN, JCPDS No. 89-7522) and cube (cubic) GaN (C-GaN , JCPDS No. 52-0791) could not be ruled out.

As can be seen from Table 1, Ga contained 89.8% of the metals and 2.89% of In.

Example  One.

2.5 g of MOCVD dust and 100 ml of 4 M hydrochloric acid (HCl) were mixed to prepare a mixed solution. The mixture was stirred at 25 DEG C and 400 rpm for 60 minutes. The filtrate was then filtered to obtain an extract.

Example  2.

An extract was obtained in the same manner as in Example 1, except that sulfuric acid (H ₂ SO ₄ ) was used instead of hydrochloric acid.

Example  3.

An extract was obtained in the same manner as in Example 1, except that nitric acid (HNO ₃ ) was used instead of hydrochloric acid.

Experimental Example  2.

In order to measure the contents of gallium, indium, aluminum and iron in the leach solutions of Examples 1 to 3, ICP-AES analysis was carried out in the same manner as in Experimental Example 1, and the results of analysis are shown in Table 2 below.

Ga (ppm) In (ppm) Al (ppm) Fe (ppm) The leach solution of Example 1 6,228.26 434.468 113.569 5.86875 The leach solution of Example 2 4,211.95 288.521 66.018 1.106 The leach solution of Example 3 5,201.32 413.565 86.391 2.08778

As can be seen in Table 2, when hydrochloric acid was used, it was found that not only gallium but also indium, aluminum and iron were leached with high efficiency.

Example  4 to  23 .

An immersion liquid was obtained in the same manner as in Example 1, except that 2 g of MOCVD dust was used and the conditions shown in Table 3 below were used.

Concentration of hydrochloric acid used Stirring time Example 4 1 M 30 minutes Example 5 1 M 60 minutes Example 6 1 M 90 minutes Example 7 1 M 120 minutes Example 8 1 M 150 minutes Example 9 2 M 30 minutes Example 10 2 M 60 minutes Example 11 2 M 90 minutes Example 12 2 M 120 minutes Example 13 2 M 150 minutes Example 14 4 M 30 minutes Example 15 4 M 60 minutes Example 16 4 M 90 minutes Example 17 4 M 120 minutes Example 18 4 M 150 minutes Example 19 5 M 30 minutes Example 20 5 M 60 minutes Example 21 5 M 90 minutes Example 22 5 M 120 minutes Example 23 5 M 150 minutes

Experimental Example  3.

In order to measure the gallium content of the leach solutions of Examples 4 to 23, ICP-AES analysis was performed in the same manner as in Experimental Example 1, and the results of the analysis are shown in Fig.

As can be seen in FIG. 3, Examples 4 to 8 using 1 M hydrochloric acid (HCl) showed the lowest leaching efficiency, and Examples 9 to 18 using 2 M hydrochloric acid or 4 M hydrochloric acid exhibited similar trends . In addition, in Examples 19 to 23 using 5 M hydrochloric acid, it was confirmed that the leaching amount of gallium was lower than that when 4 M hydrochloric acid was used.

Further, it was confirmed that the leaching solution of Examples 10 to 11 and Examples 15 to 16, which were stirred for 60 to 90 minutes, had a high gallium content.

Example  24-26.

An immersion liquid was obtained in the same manner as in Example 15, except that the stirring temperature was changed as shown in Table 4 below.

Temperature during stirring Example 24 50 ℃ Example 25 75 ℃ Example 26 100 ℃

Experimental Example  4.

ICP-AES analysis was carried out in the same manner as in Experimental Example 1, in order to measure the content of gallium and indium in the leach solution of Example 15 and Examples 24 to 26. The gallium content in the analysis results is shown in FIG. 4, Is shown in Fig.

As can be seen from FIG. 4, it was found that the gallium content in the leached solution was increased as the temperature was increased during stirring. In particular, it was found that the gallium content of the leach solution of Example 26 stirred at 100 ° C was 58.5% of the total gallium content of MOCVD dust, which was significantly higher than the leaching efficiency (29.9%) at 25 ° C. This is a result of confirming that a part of the GaN material not leached at 25 캜 is further leached due to the high temperature.

As can be seen from FIG. 5, in the case of In present in a small amount in the MOCVD dust, the lowest leaching efficiency was shown in Example 24 in which stirring at 50 ° C was performed, but stirring at 100 ° C was carried out similarly to gallium The highest leach amount was shown in Example 26. In particular, the In leaching efficiency at 100 ° C is very high, 82.7% of the indium content of the MOCVD dust. This means that most of the In present in the MOCVD dust is leached at 100 ° C.

Example  27 To 32.

In Example 15, MOCVD dust instead of MOCVD dust was mixed with Na ₂ CO ₃ and MOCVD dust at a ratio of 1: 1 by weight, and heat-treated MOCVD dust by heat treatment at 800 ° C. and air for 4 hours was used. A leaching solution was obtained in the same manner as in Example 15, except that the solvent and the agitation temperature were used.

Solvent used in mixing with MOCVD dust Stirring temperature Example 27 4 M hydrochloric acid 25 ℃ Example 28 4 M hydrochloric acid 100 ℃ Example 29 4 M sulfuric acid 25 ℃ Example 30 4 M sulfuric acid 100 ℃ Example 31 4 M sodium hydroxide 25 ℃ Example 32 4 M sodium hydroxide 100 ℃

Experimental Example  5.

In order to measure the contents of gallium, indium, aluminum and iron in the leach solutions of Examples 27 to 32, ICP-AES analysis was carried out in the same manner as in Experimental Example 1, and the results of analysis are shown in Table 6 below.

Ga (ppm) In (ppm) Al (ppm) Fe (ppm) Example 27 7,668.68 107.571 91.7620 7.61379 Example 28 8,955.42 180.211 73.3837 27.3078 Example 29 7,432.14 93.5636 64.1706 2.06137 Example 30 9,093.34 162.906 67.9887 2.33279 Example 31 7,908.86 9.13282 81.1905 0.57951 Example 32 9,079.30 35.7568 85.0741 084890

As can be seen in Table 6, the gallium content of the leachate was similar in the three leach solutions (hydrochloric acid, sulfuric acid and sodium hydroxide) regardless of the leaching temperature. In addition, the gallium content of the leachate of Examples 27 and 28 using the heat-treated MOCVD dust was significantly higher than those of Examples 15 and 24 in which the MOCVD dust was not heat treated.

On the other hand, in the case of In, low leaching efficiency was shown in the MOCVD dust heat treated than the non - heat treated MOCVD dust.

Claims (6)

1) mixing MOCVD dust with at least one solvent selected from the group consisting of hydrochloric acid, nitric acid, sulfuric acid, and sodium hydroxide;
2) stirring the mixed solution at a speed of 100 to 600 rpm for 10 to 200 minutes; And
3) filtering the stirred mixed liquor to obtain an extract, and recovering gallium or indium from the leachate; and leaching gallium, indium, or gallium and indium from the MOCVD dust.
The method according to claim 1,
Wherein the concentration of the solvent is from 1.5 to 6 M.
The method according to claim 1,
Wherein the stirring is carried out at 40 to 140 占 폚.
The method according to claim 1,
Wherein the leach liquor comprises 4,500 to 6,500 ppm of gallium and 900 to 4,500 ppm of indium.
The method according to claim 1,
Wherein the MOCVD dust is heat-treated in air at 700 to 1,000 DEG C for 1 to 5 hours.
The method according to claim 1,
Wherein the MOCVD dust is mixed with NaCO _{3 at a} weight ratio of 1: 0.5 to 2, and heat-treated at 700 to 1,000 ° C for 1 to 5 hours in air.

Images