KR101843951B1 - Method for recovering indium from target waste containing indium - Google Patents

Abstract

The present invention relates to a method for recovering indium from a target waste containing indium. According to one embodiment of the present invention, the method for recovering indium from a target waste containing indium is proposed, comprising: a leaching step of leaching and filtering the target waste containing indium (In) by leaching with a first acidic solvent and a second solvent which selectively dissolves indium from the first solvent; an impurity removing step of removing impurities by adjusting a pH by adding a basic additive to a filtrate filtered in the leaching step; and an indium recovery step of immersing a substitution material in a liquid phase from which the impurities have been removed to precipitate and recover indium by a substitution reaction.

Description

METHOD FOR RECOVERING INDIUM FROM TARGET WASTE CONTAINING INDIUM < RTI ID = 0.0 >

The present invention relates to a process for recovering indium from indium-containing target wastes. More specifically, the present invention relates to an indium recovery method capable of recovering high purity indium from indium-containing target wastes.

Recently, various metal oxide semiconductor devices have been used in display devices and the like, along with the development of various electronic devices. In particular, transparent conductive oxide (TCO) semiconductors are widely used as transparent electrode materials for display devices because of their high transmittance and excellent electrical properties. Indium tin oxide, ITO, ensures the conductivity and transparency of the display. In the display industry, indium (In) is used as the core material of a transparent conductive oxide film which is coated on a glass substrate of a flat panel display in the form of ITO to ensure conductivity and transparency.

The production yield as the conductive oxide film is only about 30 to 40% of the total amount of the ITO target material, and the remainder is generated in the form of scrap. These scrap have been generated more and more with the expansion of the display industry.

Since indium is a rare metal produced as a by-product in the smelting of zinc, the production of indium (In) is inevitable. Accordingly, the development of technology for the reuse and reuse of indium (In) in the domestic industry has been continuously carried out. Various proposals have been made by methods of recovering metal indium or indium compounds from ITO scrap.

In the case of a general metal oxide, dissolution and electrolysis are commonly used to reduce and recover metal ions to solid metals. However, in the case of oxides such as ITO, a method of precisely separating indium and tin is difficult.

Korean Registered Patent No. 10-1528598 (issued on June 12, 2015) Korean Registered Patent No. 10-1383280 (issued on April 21, 2014) Korean Patent Registration No. 10-1476168 (issued on December 24, 2014)

Disclosure of Invention Technical Problem [8] The present invention is intended to solve the above-mentioned problems. It is an object of the present invention to provide a method for more easily dissolving indium and recovering indium from a target waste containing indium by selectively dissolving indium.

In accordance with one aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: subjecting an indium (In) -containing target waste to an acidic first solvent and a second solvent that selectively dissolves indium from the first solvent, A leaching step; An impurity removing step of removing impurities by adjusting a pH by adding a basic additive to the filtrate filtered in the leaching step; And an indium recovery step of immersing the substitution material in the liquid phase from which the impurities have been removed, and recovering and recovering indium by a substitution reaction. The indium recovery method is proposed from the indium-containing target waste.

At this time, the first solvent may be a hydrochloric acid solution and the second solvent may be a hydrogen peroxide solution.

The weight ratio of the target waste having an indium content of 30 to 36 wt% and the hydrochloric acid solution having a concentration of 8 to 12 M in the leaching step ranges from 1: 0.8 to 1.2, and the hydrogen peroxide solution can be added in an amount of 0.2 to 0.4 times with respect to the weight of the hydrochloric acid solution .
In another example, the filtrate filtered in the leaching step is a strong acid with a pH of less than 1.5, and the pH is adjusted in the range of 1.5 to 2.5 in the step of removing impurities.
In addition, in the impurity removing step, the temperature of the pH-adjusted liquid is maintained within a range of 30 to 50 ° C., and the mixture is stirred for a set time, and then the impurity slurry is precipitated to remove the impurity slurry by filtration.
In addition, the filtrate from which the impurities have been removed in the indium recovery step may be diluted with pure water so that the concentration of indium is 50 to 60 g / L, and the substitute material can be immersed.

In addition, in the leaching step, a hydrochloric acid solution and a hydrogen peroxide solution are added to the target waste, and the mixture is stirred for 12 to 24 hours, and the temperature of the mixture is maintained in the range of 75 to 85 ° C.

delete

At this time, any one of sodium hydroxide, potassium hydroxide, and ammonium hydroxide or a basic substance in which they are mixed can be used as a basic additive in the impurity removing step.

Further, the basic substance may be a solid substance.

According to another example, the indium recovery step includes a substitution step of immersing a substitution material in a liquid phase from which impurities are removed, a substitution step of producing an indium sponge by a substitution reaction, and a recovery step of recovering indium metal by alkali casting the indium sponge .

At this time, aluminum or zinc having a higher ionization tendency than indium is used as a substitution material in the substitution step, and in the recovery step, any one of sodium hydroxide, potassium hydroxide and ammonium hydroxide or a basic substance mixed with them is added to the indium sponge and heated The indium metal can be recovered by separating the specific gravity afterwards.

Further, an aluminum (Al) plate having a purity of 4N or more is used as a substitute, and sodium hydroxide is added during alkali casting in the recovery step to heat the indium metal by separating the specific gravity.

In addition, at this time, the liquidus temperature in the substitution step can be maintained in the range of 40 to 50 ° C due to the substitution reaction by the aluminum plate.

Further, in one example, the indium-containing target waste is an ITO waste scrap.

According to one embodiment of the present invention, indium can be more selectively dissolved from a target waste containing indium to more easily remove impurities and efficiently recover indium.

According to another example, by recovering a low amount of indium contained in the waste, it is possible to recycle oil resources and contribute to recycling of rare metals by low-cost and high-efficiency indium recovery.

It is apparent that various effects not directly referred to in accordance with various embodiments of the present invention can be derived by those of ordinary skill in the art from the various configurations according to the embodiments of the present invention.

1 is a schematic flow diagram illustrating an indium recovery process from an indium-containing target waste according to one embodiment of the present invention.
FIG. 2 is a schematic flow chart showing an indium recovery method from an indium-containing target waste according to another embodiment of the present invention. FIG.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a block diagram showing the configuration of a first embodiment of the present invention; Fig. In the description, the same reference numerals denote the same components, and a detailed description may be omitted for the sake of understanding of the present invention to those skilled in the art.

It is to be understood that the words "comprising", "comprising", "comprising", etc. in this specification are to be understood as the presence or addition of one or more other elements or combinations thereof.

First, a method for recovering indium from indium-containing target wastes according to one embodiment of the present invention will be described with reference to the drawings.

Figures 1 and 2 are schematic flow charts illustrating indium recovery methods from indium containing target wastes, respectively, in accordance with one embodiment of the present invention.

Referring to FIGS. 1 and 2, the method for recovering indium from an indium-containing target waste according to one embodiment of the present invention includes a leaching step (S100, S100 '), an impurity removing step (S300, S300' S500 '). In the present invention, the indium-containing target wastes may be scraps containing indium. For example, it may be an ITO waste scrap. Indium Tin Oxide (ITO) is an oxide semiconductor of indium and tin, and is used as a transparent conductive oxide material for ensuring conductivity and transparency of a display.

The indium content of the target waste such as scrap is not particularly limited. The target waste is, for example, ITO abrasive sludge, dust material, and ITO process scrap, which can be suitably adjusted and recovered according to the indium content.

First, referring to FIGS. 1 and 2, in the leaching step (S100, S100 '), an indium (In) -containing target waste is treated with a first solvent which is acidic and a second solvent which selectively dissolves indium from the first solvent Leak and filter. At this time, the target waste may be provided in powder form so as to be easily dissolved by the first solvent. For example, the ITO waste can be milled and provided in powder form.

Here, referring to FIG. 2, the second solvent may be a hydrogen peroxide (H ₂ O ₂ ) solution. Hydrogen peroxide can be found to more selectively dissolve the target waste, for example, indium in the scrap. On the other hand, the first solvent may be a hydrochloric acid solution. For example, at this time, in the leaching step (S100 '), the hydrogen peroxide solution may be added 0.2 to 0.4 times the weight of the hydrochloric acid solution.

For example, in addition, in the leaching step, the hydrochloric acid solution may be a concentration of 8-12M. For example, the concentration of hydrochloric acid may be about 9 to 11M. At this time, a hydrochloric acid solution may be added so that the weight of the first solvent, hydrochloric acid solution, relative to the weight of indium contained in the target waste, is about 2.8 to 3.3 times. The weight of the hydrochloric acid solution may be about three times as much as the weight of indium contained in the target waste. In general, the content of indium contained in the ITO waste scrap may be about 30 to 36 wt%. For example, a hydrochloric acid solution may be added so that the weight ratio of the target waste and the hydrochloric acid solution as the first solvent is in the range of approximately 1: 0.8 to 1.2. For example, the weight ratio of the target waste and the hydrochloric acid solution as the first solvent may be about 1: 0.9 to 1.1. For example, a hydrochloric acid solution may be added so that the weight ratio of the 10 to 11 M hydrochloric acid solution to the target waste powder is about 1: 1. The addition of a 10 to 11 M hydrochloric acid solution at about 3 times the weight ratio to leach indium in the waste scrap that is the target waste is a ratio considering the chemical equivalence ratio of about 30 to 36% of the indium content in the scrap. For example, when the indium content in the scrap is less than 30%, excessive hydrochloric acid treatment can be solved by adjusting the pH in a post-process, but this may be accompanied by an uneconomical problem.

2, a hydrochloric acid solution and a hydrogen peroxide solution are added to the target wastes in the leaching step (S100 '), and the mixture is stirred for 12 to 24 hours while maintaining the temperature of the mixture in the range of 75 to 85 ° C. . For example, a hydrochloric acid solution and a hydrogen peroxide solution are added and stirred for 12 to 24 hours, and the temperature of the mixed solution can be maintained in the range of 75 to 85 ° C with high temperature steam.

For example, the filtrate filtered in the leaching step may be a strong acid having a pH of less than 1.5, such as less than pH 1. For example, the indium-containing leach solution which is filtered in the leaching step contains components such as tin (Sn), aluminum (Al), iron (Fe) and / or copper (Cu) in addition to indium Removal is required. Impurities such as tin (Sn), aluminum (Al), iron (Fe) and / or copper (Cu) and the like can be partially removed through the subsequent impurity removal step (S300, S300 ').

Residual residues that leach out in this process may be separated by filtration or may be re-leached.

Next, the impurity removal step (S300) will be described. In the impurity removal steps (S300 and S300 '), a basic additive is added to the filtered filtrate in the leaching step (S100, S100') to adjust the pH to remove impurities. In this step, a process for removing tin (Sn), which is a major impurity, is performed. At this time, tin hydroxide, which is a main impurity, can be removed by tin hydroxide to adjust the pH.

For example, referring to FIG. 2, the pH is adjusted in the range of 1.5 to 2.5 in the impurity removal step (S300 '). For example, a basic additive may be added to the filtrate to adjust the pH to about 2 or so.

At this time, in the impurity removal step (S300 '), any one of sodium hydroxide, potassium hydroxide, ammonium hydroxide, or a basic material mixed with them may be used as the basic additive. In this case, in one example, the basic substance is a solid phase material. In the impurity removing step (S300 '), the temperature of the pH-adjusted liquid is maintained in the range of 30 to 50 ° C., And an impurity slurry, such as a tin hydroxide slurry, may be removed by filtration.

For example, in one embodiment, solid NaOH (98%) is used as a pH controller to remove tin (Sn) as a major impurity by tin hydroxide with pH control. Liquid caustic soda (NaOH) is also possible, but it may be preferable to use caustic soda of solid state in consideration of the solution volume and the like when adjusting the pH to about 2 or less. For example, at this time, the temperature of the pH-adjusted liquid is maintained at 30 ° C to 50 ° C while stirring for about 60 minutes, and the mixture is allowed to stand for about 4 hours to remove the impurity slurry, for example, the tin hydroxide slurry by precipitation. The precipitated impurity slurry can be filtered off by filtration.

Next, the indium recovery step (S500, S500 ') will be described. Referring to FIGS. 1 and 2, in the indium recovery step (S500, S500 '), the replacement material is immersed in the liquid phase in which the impurities are removed in the impurity removal steps (S300 and S300').

For example, referring to FIG. 2, the indium recovery step S500 'may include a replacement step S510 and a collection step S530. In the replacing step (S510), the substitution material is immersed in the liquid phase from which the impurities have been removed, and an indium sponge is produced by the substitution reaction. In the collection step S530, the indium sponge produced in the replacing step S510 is collected and the indium sponge is subjected to alkali casting to recover the indium metal.

At this time, in the replacing step (S510), aluminum (Al) or zinc (Zn) having a higher ionization tendency than indium can be used as a substitute. Al and Zn are used as substituents, but the amount of Al consumed when recovering 100 g of indium is 23.5 g and the consumption of Zn is 85.4 g. Therefore, the use of Al is more economical.

For example, an aluminum (Al) plate having a purity of 4N or more can be used as a substitute material. That is, the impurity slurry is removed by using a filtering bed, and the filtrate is put into a substitution tank, and 4N Al plate is immersed to obtain an indium sponge. For example, the filtrate from which the impurity slurry has been removed is diluted with pure water so that the concentration of indium is about 50 to 60 g / L, and the 4N Al plate is immersed to obtain an indium sponge.

At this time, it is possible to maintain the liquidus temperature in the range of 40 to 50 ° C according to the substitution reaction by the aluminum plate in the substitution step. For example, the number of Al plates for dipping or / and the immersion height of the plate are adjusted so that the liquid temperature is maintained at about 40 to 50 캜. If the number of dipping Al plate to commit a large amount when the initial substituted, causing the solution temperature goes above 50 ℃, a large amount of Al ^{+ 3} is generated and thereby inhibiting the substitution reaction. On the other hand, the liquid temperature of 40 ° C or less slows the substitution reaction and lengthens the indium recovery period, which is inefficient.

In addition, when the concentration of indium ions in the liquid reaches about 30 mg / L, the indium sponge is collected into a mass using a massing compressor.

In the recovering step (S530), the indium sponge can be recovered from the indium metal (ingot) by adding any one of sodium hydroxide, potassium hydroxide and ammonium hydroxide or a solid base material mixed therewith and heating it to separate the specific gravity. At this time, a method of casting an indium ingot by heating a solid basic material into an indium sponge is called an alkali casting.

For example, sodium hydroxide (caustic soda, NaOH) may be added during the alkali casting in the recovery step (S530) and the indium metal may be recovered by heating to separate the specific gravity. For example, indium sponge lumps collected in an alkali casting tank and solid caustic soda (NaOH) may be charged and heated to separate the specific gravity to recover indium metal. Alkali casting can prevent the removal of impurities in the indium sponge and oxidation of the indium surface. The amount of solid NaOH used is suitably about 25 to 35%, for example, about 30% of the weight of the indium sponge. The solid caustic soda may be sodium hydroxide hydrate.

Next, results obtained through the following [Example 1] and [Comparative Example 1] will be described.

[Example 1] ITO scrap was prepared by leaching indium using hydrochloric acid and hydrogen peroxide and adjusting pH to about pH 2 to remove impurities and recovering indium. On the other hand, in Comparative Example 1, ITO scrap was obtained by leaching indium without using hydrogen peroxide and recovering indium without adjusting the pH to about pH 2.

[ Example  One]

First, ITO scrap (ITO abrasive dust) as a target waste is prepared.

100 g of 10 M hydrochloric acid is placed in a 1 L beaker and heated with a hot plate at a temperature of about 75 캜 and stirred at about 30 RPM on an experimental stirrer. 100 g of the prepared ITO scrap (ITO abrasive dust material) is gradually added.

20 g of hydrogen peroxide (35%) is added after completion of the addition of the ITO strap, and the solution is stirred for about 24 hours at a temperature in the range of about 75 ° C to 85 ° C to induce indium to be filtered out. At this time, the filtered filtrate was analyzed using ICP (Thermo, iCAP6000) and the results are shown in Table 1 below.

Solid NaOH (98%) is added to the leached filtrate to adjust the pH to about 2, and the solution is stirred at about 30 RPM for about 60 minutes while heating the solution to about 30 to 50 ° C. The solution is allowed to stand for about 4 hours while maintaining the temperature of the solution at about 30 ° C to 50 ° C to precipitate impurities such as Sn, Fe, and Al.

The impurities precipitated were filtered, and the filtered filtrate was analyzed using ICP (Thermo, iCAP6000). The results are shown in Table 2 below.

The filtrate from which the impurities have been removed is diluted with pure water so that the concentration of indium is about 50 to 60 g / L, and 4N Al pieces (700 x 300, 1t) are immersed and replaced.

The solution temperature was adjusted to be in the range of 40 to 50 ° C. while adjusting the immersion height. After about 36 hours, the concentration of the indium (In) ion in the solution was about 30 mg / L.

The resulting indium sponge was well mixed and mixed with solid caustic soda to recover In metal. The recovery and analysis results are shown in Table 3 below.

[ Comparative Example  One]

100 g of 10 M hydrochloric acid was added to a 1 L beaker as in Example 1 described above, and the mixture was heated with a hot plate at a temperature of about 75 캜 and stirred at about 30 RPM on an experimental stirrer. 100 g of the prepared ITO scrap (ITO abrasive dust material) is gradually added.

After the completion of the charging of the ITO strap, the temperature of the solution is stirred for about 24 hours in the range of about 75 ° C to 85 ° C, and indium is leached out and filtered with a filter. At this time, the filtered filtrate was analyzed using ICP (Thermo, iCAP6000) and the results are shown in Table 1 below.

The leached filtrate is diluted with ultrapure water to a concentration of indium of approximately 50 to 60 g / L, and 4N Al pieces (700 x 300, 1t) are immersed and replaced.

The solution temperature was adjusted to be in the range of 40 to 50 ° C. while adjusting the immersion height. After about 36 hours, the concentration of the indium (In) ion in the solution was about 30 mg / L.

The resulting indium sponge was well mixed and mixed with solid caustic soda to recover In metal. The recovery and analysis results are shown in Table 3 below.

Table of properties of leached filtrate (unit: mg / L)
division
In
Sn
Cu
Fe
Zn
Pb
Al
Example 1
85,000
26,600
260
20
20
115
2
Comparative Example 1
73,000
71,000
350
800
18
110
30
Contrast result
(+) 12,000
(-) 44,400
(-) 90
(-) 780
(+) 2
(+) 5
(-) 28

Property of the filtrate according to pH adjustment of [Example 1] (unit: mg / L)
division
In
Sn
Cu
Fe
Zn
Pb
Al
Before pH adjustment
85,000
26,600
260
20
20
115
2
After pH adjustment
81,000
15,000
250
2
19
110
0
increase
(-) 4,000
(-) 11,500
(-) 10
(-) 18
(-)One
(-) 5
(-)2

Indium recovery (g) and component analysis results
division indium
Recovery (g)
In (%)
Sn (mg / L)
Cu (mg / L)
Fe (mg / L)
Zn (mg / L)
Pb (mg / L)
Example 1
76.95
98.52
14,500
153
2
15
110
Comparative Example 1
65.70
92.98
69,000
300
720
15
98
prepare
(+) 11.25
(+) 5.54
(-) 50,500
(-) 147
(-) 718
0
(+) 12

In Table 3, the indium purity of [Example 1] according to the example of the present invention was 98.52%, which was 5.54% higher than the purity of 92.98% of [Comparative Example 1].

The foregoing embodiments and accompanying drawings are not intended to limit the scope of the present invention but to illustrate the present invention in order to facilitate understanding of the present invention by those skilled in the art. Embodiments in accordance with various combinations of the above-described configurations can also be implemented by those skilled in the art from the foregoing detailed description. Accordingly, various embodiments of the present invention may be embodied in various forms without departing from the essential characteristics thereof, and the scope of the present invention should be construed in accordance with the invention as set forth in the appended claims. Alternatives, and equivalents by those skilled in the art.

Claims (12)

The indium (In) -containing target waste is leached by using a second solvent that is higher in the selective dissolving power for indium among the first solvent of acidic and tin which is the main impurity contained in the target waste and the target of recovery, indium Leaching step for filtration;
An impurity removing step of removing impurities by adjusting a pH by adding a basic additive to the filtrate filtered in the leaching step; And
And an indium recovery step of immersing the substitution material in the liquid phase from which the impurities have been removed to precipitate and recover the indium by a substitution reaction,
Wherein the first solvent is a hydrochloric acid solution and the second solvent is a hydrogen peroxide solution,
In the leaching step, the weight ratio of the target waste having an indium content of 30 to 36 wt% and the hydrochloric acid solution having a concentration of 8 to 12 M is 1: 0.8 to 1.2, the hydrogen peroxide solution is added 0.2 to 0.4 times the weight of the hydrochloric acid solution,
Wherein the filtrate filtered in the leaching step has a pH of less than 1.5,
In the impurity removing step, the pH is adjusted to a range of 1.5 to 2.5, the temperature of the pH-adjusted liquid is maintained in a range of 30 to 50 ° C., and the mixture is stirred for a set time. Thereafter, the impurity slurry is precipitated, and the impurity slurry is removed by filtration and,
The indium-containing target wastes are impregnated with the indium-containing target wastes by diluting the filtrate from which the impurities have been removed with pure water in the indium recovery step so that the concentration of indium is 50 to 60 g / L, Recovery method.
delete delete In claim 1,
Wherein the hydrochloric acid solution and the hydrogen peroxide solution are added to the target waste in the leaching step, the mixture is stirred for 12 to 24 hours, the temperature of the mixture is maintained in the range of 75 to 85 ° C, and the mixed solution is leached and filtered. ≪ / RTI >
delete In claim 1,
Wherein the impurity removing step uses a solid phase basic material containing any one of sodium hydroxide, potassium hydroxide and ammonium hydroxide or a mixture thereof as the basic additive.
delete The method according to any one of claims 1, 4 and 6,
The indium recovery step may include a substitution step of immersing the substitute material in the liquid phase from which the impurities have been removed to produce an indium sponge by a substitution reaction, and a recovery step of recovering indium metal by alkali casting the indium sponge Containing indium-containing target wastes.
In claim 8,
In the replacing step, aluminum or zinc having a higher ionization tendency than indium is used as a substitute,
In the recovering step, the indium sponge is heated by adding any one of sodium hydroxide, potassium hydroxide, and ammonium hydroxide or a solid basic material mixed therewith, and separating the specific gravity to recover the indium metal. Indium recovery method.
In claim 9,
An aluminum (Al) plate having a purity of 4N or more was used as the replacement material,
Wherein the sodium hydroxide is added during alkali casting in the recovering step.
In claim 10,
Wherein the liquid phase temperature is maintained in the range of 40 to 50 ° C. according to the substitution reaction by the aluminum plate in the replacing step.
The method according to any one of claims 1, 4 and 6,
Wherein the indium-containing target waste is an ITO waste scrap.

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