KR20160100277A - Quantitative analysis method of tin in the ito - Google Patents

Abstract

The present invention relates to a quantitative analysis method of tin contained in indium tin oxide (ITO). The quantitative analysis method of tin contained in ITO comprises: a step of dissolving ITO in hydrochloric acid, and then manufacturing a solution by filtering; a step of adding ammonia water to the solution to have a hydrogen ion concentration (pH) of 7-8 to produce metal hydroxide; a step of washing the metal hydroxide using pure water; a step of applying a nitrate solution to the metal hydroxide washed using pure water to produce metastannic acid (H_2SnO_3); a step of washing the metastannic acid using the nitrate solution; a step of inserting the metastannic acid washed using nitric acid into a porcelain crucible with a known weight, and applying the nitrate solution to intensely heat the metastannic acid to measure mass of remaining tin oxide (SnO_2); and a step of using the measured mass of the tin oxide to calculate a weight percent content of tin contained in ITO. The quantitative analysis method of tin according to the present invention can accurately measure a content of tin existing in ITO at a ratio of several weight percent.

Description

TECHNICAL FIELD The present invention relates to a method for quantitative analysis of tin contained in ITO,

TECHNICAL FIELD The present invention relates to a quantitative analysis method of tin contained in ITO, and more particularly, to a tin quantitative analysis method capable of accurately measuring the content of tin contained in ITO at a concentration of several wt% And a quantitative analysis method.

Indium tin oxide (ITO), which is a compound of indium oxide (In ₂ O ₃ ) and tin oxide (SnO ₂ ), which is used as a transparent electrode in various smart devices and the like, depends on the content of indium oxide and tin oxide Electrical conductivity and the like.

Therefore, it is necessary to accurately control the content of indium oxide and tin oxide contained in ITO in order to produce ITO having desired physical properties such as electrical conductivity and the like.

In order to precisely control the content of indium oxide and tin oxide contained in ITO, the content of indium oxide or tin oxide contained in ITO is accurately measured to further add the deficient compound of indium oxide or tin oxide to obtain the most preferable electric conductivity It becomes possible to produce ITO having a high dielectric constant.

It is also important to accurately measure indium and tin content in the process of recovering expensive indium and tin from waste ITO. This is because indium and tin content are important indicators of the transaction between the companies that generate waste ITO and the companies that collect waste, and it is an important indicator for the recovery rate of indium and tin in the recovery process.

Conventionally, a method of mechanically measuring the content of tin oxide by using ICP (inductively coupled plasma) to quantitatively analyze tin oxide or tin in ITO has been used. However, ICP is a method of measuring the content of trace elements It is suitable for quantitative analysis but is not suitable for quantitative analysis of an element contained at a concentration of several to several tens% by weight. That is, tin is contained in the ITO in an amount of about 7 to 8% by weight, and therefore, the accuracy of the quantitative analysis of tin (Sn) contained in ITO using ICP is inevitably lowered.

On the other hand, Patent Document 1 discloses a method for recovering indium tin oxide by precipitating hydrates by hydrothermal reaction and neutralizing the solution obtained by dissolving scrap containing indium tin oxide in an acid, and recovering indium tin oxide. There is no method of calculating the exact content of tin contained in the solution. In Patent Document 2, the solution obtained by dissolving the indium compound in hydrochloric acid is neutralized with an alkali to treat the precipitated hydroxide with hydrogen sulfide gas, And the indium is recovered by withdrawing indium by using the remaining stock solution. However, this method is also insufficient to accurately measure the content of tin contained in ITO.

Therefore, there is an urgent need to develop a method capable of accurately quantitatively analyzing tin contained in ITO in an amount of several weight percent.

[Patent Literature]

Patent Document 1: JP-A-2013-006710

Patent Document 2: Japanese Patent Application Laid-Open No. 2000-169991

In order to solve the above problems, the present invention solves the above problem by dissolving ITO in an acid, neutralizing it with a base, neutralizing the metal hydroxide with nitric acid, and then using meta-tartaric acid, The content of tin contained in the ITO can be accurately measured by a wet analysis method for calculating the content of the tin. The present invention has been completed based on this finding.

Therefore, one aspect of the present invention is to provide a quantitative analysis method of tin capable of accurately measuring the content of tin contained in ITO at a concentration of several wt%.

According to one embodiment of the present invention, there is provided a method for quantitatively analyzing tin contained in ITO, comprising the steps of: dissolving indium tin oxide (ITO) in hydrochloric acid to prepare a dissolution solution; Adding ammonia water to the dissolution solution so as to have a hydrogen ion concentration (pH) of 7 to 8 to produce a metal hydroxide; Washing the metal hydroxide with pure water; Adding nitric acid solution to the washed metal hydroxide to produce meta-tartaric acid (H ₂ SnO ₃ ); Washing said meta-tartaric acid with dilute nitric acid solution; Adding the washed meta-tartaric acid to a porcelain crucible, adding one or two drops of a nitric acid solution to the residue, and measuring the mass of the remaining tin oxide (SnO ₂ ); And calculating the weight% content of tin contained in the ITO using the measured mass of tin oxide.

In another embodiment, the wt% content of the annotation, for example, formula Sn (%) = {(m 1 × 0.7876) / m 0} × 100 ( wherein, m ₁ is a comment on the measured oxidation And m ₀ is the mass of the indium tin oxide used as the analytical sample).

In another embodiment of the present invention, the dissolution solution may be prepared by dissolving powdered indium tin oxide (ITO) in hydrochloric acid and then filtering the solution.

In another embodiment of the present invention, the metal hydroxide may be one comprising indium hydroxide (In (OH) ₃ ) and tin hydroxide (Sn (OH) ₄ ).

In another embodiment of the present invention, the pure water may be deionized water having a resistance of 12 to 18 M? 占 ㎝ m.

In another embodiment of the present invention, the nitric acid solution used in the step of producing the meta-tartaric acid (H ₂ SnO ₃ ) may be a mixture of nitric acid and water at a volume ratio of 1: 1, The nitric acid solution used in the step may be a mixture of nitric acid and water in a volume ratio of 1:10.

In another embodiment of the present invention, the method may further comprise the step of filtering the solution after the step of producing the solution.

In another embodiment of the present invention, the method may further comprise filtering the metal hydroxide with filter paper after the step of producing the metal hydroxide.

In another embodiment of the present invention, the method may further comprise filtering the meta-tartaric acid with filter paper after the step of producing the meta-tartaric acid (H ₂ SnO ₃ ).

In another embodiment of the present invention, the method may further comprise the step of measuring the concentration of tin in the liquid passing through the filter paper after filtering the meta-tartaric acid with filter paper.

In another embodiment of the present invention, the ignition may be performed at 900 to 1,100 ° C, preferably 1,000 ° C for 30 to 90 minutes, preferably 60 minutes.

The method of quantitative analysis of tin according to the present invention has an advantage that it can measure the content of tin present in ITO at a ratio of several weight% very accurately, and the content of impurities such as copper, iron or aluminum contained in ITO is indirectly , It has an advantage that the degree of purity of ITO can be confirmed with high reliability. In addition, the method for quantitative analysis of tin according to the present invention is advantageous in that it can be used as a wet analysis method useful in the field of waste ITO regeneration by making it possible to accurately measure the content of indium and tin when recovering expensive indium and tin from waste ITO .

FIG. 1 is a test result performed by the Korean Chemical Fusion Test Institute using the method of Example 1 according to an embodiment of the present invention. FIG.
FIG. 2 is a test result performed by the Korean Chemical Fusion Test Institute using the method of Example 2 according to an embodiment of the present invention. FIG.
FIG. 3 is a test result performed by the Korean Chemical Fusion Test Institute according to the method of Example 3 according to an embodiment of the present invention.

Before describing the invention in more detail, it is to be understood that the words or words used in the specification and claims are not to be construed in a conventional or dictionary sense, It should be interpreted as meaning and concept consistent with the technical idea of the present invention. Therefore, the constitution of the embodiments described in the present specification is merely a preferred example of the present invention, and does not represent all the technical ideas of the present invention, so that various equivalents and variations And the like.

Hereinafter, preferred embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

The present invention relates to a method for accurately and accurately quantifying the content of tin contained in indium tin oxide, that is, indium tin oxide (ITO).

Indium tin oxide (ITO) is a compound of indium oxide (In ₂ O ₃ ) and tin oxide (SnO ₂ ) and is generally composed of about 90 wt% indium oxide and about 10 wt% tin oxide do. Indium tin oxide is transparent and colorless in the thin film state and yellow to green in the lump state. Indium tin oxide is often referred to as a transparent electrode and is referred to as ITO since it has excellent electrical conductivity and optical transparency in a thin film state. Indium tin oxide thin films are generally deposited on the surfaces of various electronic devices by electron beam evaporation, vapor deposition, sputtering, or the like. At present, due to the problems of high cost of ITO, limited indium resources, brittleness characteristic, low bending property of indium tin oxide thin film, and high vacuum required for thin film deposition, carbon nanotube conductive coating, doped aluminum, zinc oxide, PEDOT (3,4-ethylenedioxythiophene) or PEDOT-PSS (poly (3,4-ethylenedioxythiophene) polystyrene sulfonate) thin films have been researched. However, most of the transparent electrodes are still using ITO to be.

In order to produce ITO having a desired electric conductivity, indium oxide and tin oxide (ITO) contained in ITO are used as transparent electrodes in various smart devices and the like because they show differences in electrical conductivity depending on the contents of indium oxide and tin oxide. It is necessary to accurately control the content of the catalyst. ITO is produced by mixing indium oxide and tin oxide, which are raw materials, with each other. The purity of indium oxide and tin oxide used in the production of ITO is required to be as high as 99.995 to 99.999%. However, the high purity of the indium oxide or tin oxide is not always guaranteed. Therefore, the degree of tin contained in the ITO produced by using indium oxide and tin oxide, which are the raw materials used, It is possible to calculate more accurately by quantitatively analyzing components such as tin. If the content of tin analyzed quantitatively as described above is lower than the expected content of tin, it is possible to produce ITO having a desired electrical conductivity by further adding the same amount of the tin oxide as the raw material. If the content of tin Is higher than the predicted tin content, ITO having a desired electric conductivity can be produced by further adding indium oxide as much as the corresponding amount of the indium oxide. That is, ITO having a desired electric conductivity can be produced even if the raw materials of indium oxide and tin oxide having unpredictable purity are used.

However, when tin oxide (or tin) or indium oxide (or indium), which is indispensably required for obtaining a desired electric conductivity in the process of manufacturing ITO using indium oxide and tin oxide as the raw materials having various purity, It is not a very easy process to quantify accurately.

Conventionally, an ICP apparatus is used for quantitatively analyzing tin oxide or tin present in ITO. However, this may be a certain degree of reliability when used for quantitative analysis of a trace amount of element in several ppm or ppb units, When quantitatively analyzing a component contained in a concentration of several tens% by weight, there is a problem that the reliability is very low.

In general, about 7 to 8% by weight of tin is contained in ITO, and the present inventors can accurately analyze the weight of tin contained in ITO at a content ratio of several wt% And developed a breakthrough and reliable quantitative analysis method.

A method for quantitative analysis of tin according to an embodiment of the present invention includes the steps of: dissolving ITO in hydrochloric acid to prepare a dissolution solution; Adding ammonia water to the dissolution solution so as to have a hydrogen ion concentration (pH) of 7 to 8 to produce a metal hydroxide; Washing the metal hydroxide with pure water; Adding nitric acid solution to the metal hydroxide washed with pure water to produce meta-tartaric acid (H ₂ SnO ₃ ); Washing the meta-tartaric acid with a nitric acid solution; The meta-tartaric acid washed with nitric acid is preliminarily weighed into a weighed porcelain crucible whose weight is known, and then the mass of the tin oxide (SnO ₂ ) is measured; And calculating a weight% content of tin using a constant formula.

An example of a mathematical expression used in the quantitative analysis method is shown in Equation 1 below.

[Equation 1]

Sn (%) = {(m ₁ x 0.7876) / m ₀ } x 100

In Equation 1, m ₁ is the mass of the measured tin oxide (SnO ₂ ), and m ₀ is the mass of the indium tin oxide powder sample. In Equation (1), the constant 0.7876 is the ratio of molecular weight occupied by tin in tin oxide (SnO ₂ ), which is calculated by taking the average molecular weight calculated by considering the ratio of various isotopes of tin and oxygen present in nature . Therefore, when the molecular weight of the isotopes of tin and oxygen used in actual experiments can be accurately known, the constants can be changed accordingly.

On the other hand, the category of the present invention is not limited to the above formula (1), and the content percentage of tin can be calculated by various formulas and the like.

Meanwhile, the ITO used as a sample in the present invention is preferably prepared in powder form. That is, ITO in powder state is more reactive with hydrochloric acid than ITO in bulk state, and more accurate quantitative analysis is possible. Various methods known in the art can be used as a method of making the ITO in a solid lump state into a powder, that is, a powder.

Meanwhile, it is possible to use 35% -HCl specified in KS M ISO 6353-2 (R13) as the hydrochloric acid (HCl) used in the present invention. The hydrochloric acid used in the present invention reacts with ITO in a powder state to form a tin salt (Sn (Cl) ₄ ) And indium salt (In (Cl) ₃ )) and water (H ₂ O). Although the amount of hydrochloric acid used in the present invention can be 20 to 30 ml of 35% -HCl per 10 g of ITO in powder form, the amount of hydrochloric acid used is not limited to this ratio, and the amount of ITO powder sampled It is sufficient to use enough hydrochloric acid to dissolve.

Through the above procedure, a solution in which ITO is dissolved in hydrochloric acid is taken by a pipette or the like, and then the solution is poured into a beaker, and ammonia water (NH ₄ OH) is added to neutralize the solution so that the pH of the solution becomes 7 to 8. The beaker can use various kinds of beakers. When 10 ml of the solution is used, it is easy to work with about 200 ml of tolbicer, but the scope of the present invention is not limited to the beaker size and the like . Meanwhile, the ammonia water is gradually added to the solution by using a variety of tools such as a pipette, and the electrode of the pH meter is brought into contact with the solution, and the pH meter is continuously checked while slowly adding ammonia water. Stop adding ammonia water.

When ammonia water is added to the solution in which ITO is dissolved in hydrochloric acid and the pH of the solution becomes 7 to 8, a precipitate of metal hydroxide is formed in the beaker. The precipitated metal hydroxides are indium hydroxide (In (OH) ₃ ) and tin hydroxide ((Sn (OH) ₄ ), which are precipitated in solution in a solid state.

In order to filter only the thus produced indium hydroxide and tin hydroxide, the solution contained in the beaker is poured onto the filter paper together with the precipitate to filter the hydroxides over the filter paper, and the remaining liquid is passed through the filter paper to another beaker .

It is possible to use a variety of standardized filter paper, for example, a filter paper of 5C size can sufficiently filter out indium hydroxide and tin hydroxide.

The metal hydroxide thus filtered is thoroughly washed with water on the filter paper to remove any foreign substances other than the metal hydroxide. In this case, pure water is used. The pure water means pure water (H ₂ O) as well as water containing almost no ion components such as various minerals, which means deionized water in which all ions have been removed (ie, deionized). Such deionized water is pure water having a resistance of, for example, 12 to 18 M? 占, m, preferably 18 M? 占. M. Washing with pure water is usually sufficient to wash 4 to 5 times.

On the other hand, the liquid contained in the other beaker passing through the filter paper is used to determine whether indium or tin is contained by ICP or the like (in this case, even if indium or tin is present, ). If the content of indium or tin measured in the liquid is experimentally negligible, the metal hydroxide may be further extracted by adding ammonia water to the liquid again. On the other hand, if indium or tin is hardly detected (less than 5 ppm) in the liquid through the above process, metal hydroxide can be considered to be sufficiently reliable in the neutralization process using the ammonia water.

The thus filtered and washed metal hydroxides (i.e., indium hydroxide and tin hydroxide) are placed in a new beaker, a sufficient amount of nitric acid solution is added, and the beaker is covered with a watch glass. At this time, make sure that the convex part of the watch plate faces the beaker direction. Since the convex portion of the watch plate is directed to the beaker, the gas component generated during the reaction is condensed on the watch glass and can be easily dropped to the beaker, thereby preventing the disappearance of the reactant, thereby enabling a more accurate quantitative analysis.

The nitric acid solution used herein is a mixture of 1 volume of nitric acid and 1 volume of water specified in KS M ISO 6353-2 (R19), and the metal hydroxide contained in the beaker is reacted with the nitric acid solution for at least 30 minutes Or more.

When the nitric acid solution reacts with the metal hydroxide, the indium hydroxide in the metal hydroxide is completely dissolved in the nitric acid. In the case of the tin oxide, the tin is dissolved in the nitric acid, and then the tin reacts with the nitric acid again to form meta-tartaric acid (H ₂ SnO ₃ ) (Ideally, all the tin contained in the tin oxide becomes the tin component of the meta-tartaric acid). At this time, sufficient reaction is carried out to allow the indium hydroxide to dissolve completely and all of the solid components disappear and the tin component of the tin oxide becomes the tin component of the meta-tartaric acid at room temperature for at least 1 hour.

To filter out the solid meta-tartaric acid thus produced, the beaker-containing solution and the meta-tartaric acid solid precipitate are poured onto the filter paper, and the liquid passed through the filter paper is placed in the other beaker. A variety of standard sizes can be used for the filter paper used. For example, when the filter paper having a size of about 5C is used, meta-tartaric acid can be sufficiently reliably filtered. In this way, meta-tartaric acid filtered on the filter paper is thoroughly washed with a nitric acid solution to sufficiently remove foreign substances other than meta-tartaric acid. The nitric acid solution used here is a mixture of 1 volume of nitric acid and 10 volumes of water specified in KS M ISO 6353-2 (R19). At this time, by washing with a nitric acid solution instead of water, impurities other than meta-tartaric acid are removed, and at the same time, some indium hydroxide which remains unreacted with nitric acid and remains in a solid state can be dissolved once again on the filtration paper. Quantitative analysis becomes possible.

On the other hand, the liquid that has passed through the filter paper uses ICP or the like to check whether or not the tin component is contained in the liquid which has passed through the filter paper. If tin components are detected that affect the reliability of the quantitative analysis, the experiment may be repeated or nitric acid (1: 1) may be added to the residual tin to form meta-tartaric acid completely. If tin is scarcely detected in the liquid passing through the filter paper, it means that meta-tartaric acid has been obtained to a sufficiently reliable degree.

The thus filtered and washed meta-tartaric acid is thoroughly dried in an air bath at 100 to 105 ° C for about 1 hour together with the filter paper, and then the thus dried meta-tartaric acid and the filter paper are transferred to the porcelain crucible. If meta-tartaric acid is separated from the filter paper, there is a possibility that trace meta-tartaric acid may remain in the filter paper. Thus, the meta-tartaric acid is dried without being separated from the filter paper and is put into the porcelain crucible together with the process A more reliable quantitative analysis becomes possible.

At this time, a small amount of nitric acid solution (1: 1) is added to the meta-tartaric acid contained in the porcelain crucible to completely dissolve indium hydroxide which may be remaining even once, and more reliable quantitative analysis becomes possible through this process .

Thereafter, incinerating the porcelain crucible with meta-tartaric acid and filter paper inside. The temperature of the electric furnace is gradually raised to about 5 to 10 ° C per minute, and the temperature of the electric furnace is raised to about 15 ° C per minute at about 400 to 500 ° C. Finally, the temperature is raised to 900 to 1,100 ° C , Preferably to 1,000 ° C. The temperature is maintained at such final temperature for about 30 to 90 minutes, preferably for 1 hour.

Through the ignition process, the hydrogen (H) component of meta-tartrate (H ₂ SnO ₃ ) is completely evaporated and the tin (Sn) and oxygen (O) components are rearranged. As a result, It is changed to pure tin oxide (SnO ₂ ).

This ignition process is performed until the meta-tartaric acid turns into tin oxide and the tin oxide no longer causes a change in weight, that is, a constant amount (= constant weight).

On the other hand, the self-potting crucible used is one that has been accurately weighed in advance. In particular, when the porcelain crucible is subjected to an electric furnace having a temperature of about 1,000 ° C., the weight changes due to evaporation of its own water and the like. Therefore, the experimental error can be minimized by previously measuring the weight change of the porcelain crucible. On the other hand, the filter paper is changed into ash through the heat treatment process, and the weight of the ash becomes completely negligible. In addition, the residual indium hydroxide dissolved by the nitric acid solution and the nitric acid solution added to the porcelain crucible is completely evaporated and lost in the liquid state, so that the mass relating to the indium hydroxide is negligible.

The porcelain crucible with the end of the ignition is transferred to a desiccator, cooled slowly at room temperature for about one hour, and the mass of the tin oxide remaining in the porcelain crucible is measured in consideration of the weight of the pre-determined crucible itself. At this time, since the weight of the porcelain crucible is measured in advance, it is not necessary to measure the mass of the tin oxide separately from the porcelain crucible, and the weight of the porcelain crucible containing the tin oxide can be measured to calculate the mass of the tin oxide. As a result, even when a tin oxide is taken in the porcelain crucible, even a small amount of tin oxide remains in the porcelain crucible, thereby preventing an error in the measured mass of the tin oxide.

By using the mass of tin oxide thus measured, the content by weight of tin is accurately measured through a formula or the like.

The above formula may be variously modified. For example, it is possible to calculate the weight% content of tin by the above-mentioned equation (1).

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the scope of the present invention is not limited to the following examples.

Example 1

(22.0 g) of indium tin oxide, which was confirmed to be a mixture of 7.20 wt% of Sn in the ITO, was prepared from a manufacturer of indium oxide and tin oxide, which are raw materials for ITO, -2 (R-13) was used), and the solution was prepared once every time. Using a micropipette, take 10 ml of the solution prepared above, place it in a 200 ml tall beaker, and mix it with ammonia water (KS M ISO 6353-2 (R- (OH) ₃ and Sn (OH) ₄ were prepared by the neutralization reaction, and the pH of the solution was adjusted to 7 by observing the pH value of the solution by slowly dropping a drop of the solution And allowed to stand for about 30 minutes so as to be sufficiently generated. Thereafter, all of the solution and the precipitate contained in the beaker are slowly poured onto the sifted paper 5C so that In (OH) ₃ and Sn (OH) ₄ are sufficiently filtered on the sifted paper, Was added to another 200 ml tall beaker. Using ICP, it was confirmed that tin and indium components were less than 5 ppm (N / D: not detected), respectively, in the liquid passed through the filter paper, and then pure water having a resistance of 18 M? In (OH) ₃ and Sn (OH) ₄ were washed five times. The thus filtered and washed In (OH) ₃ and Sn (OH) ₄ were transferred to a 200 ml tall beaker, and a nitric acid solution (1 volume of nitric acid specified in KS M ISO 6353-2 (R19) ) Was added to the beaker, and the beaker was covered with a watch plate so that the convex portion of the watch plate faced the beaker, followed by reaction for 30 minutes. Thereafter, it was allowed to stand at room temperature for 1 hour, and then slowly poured onto the sifted paper (5C) so that the solid sediment was filtered on the sifted paper, and the liquid passed through the sifted paper was placed in another beaker. After confirming that the content of tin in the liquid contained in the other beaker was less than 5 ppm (N / D: not detected) using ICP, 1 volume of nitric acid (KS M ISO 6353-2 (R19) 10 volume) was used to wash the precipitate filtered on the filter paper five times. The thus filtered and washed precipitate was dried together with the filter paper at about 100 ° C. for 1 hour and then weighed in a pre-measured porcelain crucible before and after ignition for 1 hour in an electric furnace at 1,000 ° C., and a nitric acid solution (KS M 2 volts of a mixture of 1 vol. Of nitric acid and 10 vol. Of water specified in ISO 6353-2 (R19)) was wetted by pipette and then put into an electric furnace for ignition. The ignition was gradually heated to 400 DEG C at an initial rate of 10 DEG C / min and then heated at a rate of 15 DEG C / min. The temperature was finally maintained at 1,000 ° C. for 1 hour. Thereafter, the porcelain crucible was taken out of the electric furnace, put in a desiccator, and cooled to room temperature for about 1 hour. After the porcelain crucible was cooled, the weight of the tin oxide (SnO ₂ ) remaining in the porcelain crucible And the content by weight of tin was calculated by the following formula (1). The results are shown in Table 1 below (see FIG. 1).

[Equation 1]

Sn (%) = {(m ₁ x 0.7876) / m ₀ } x 100 wherein m ₁ is the mass of the measured tin oxide and m ₀ is the mass of the indium tin oxide powder sample.

Example 2

Using the same method as in Example 1, 22.0 g of indium tin oxide confirmed to be a mixture of 7.12 wt% of Sn in ITO was prepared from indium oxide and tin oxide, which are raw materials for ITO, %. The results are shown in Table 1 (see Fig. 2).

Example 3

Using 22.0 g of indium tin oxide, which was confirmed to be a mixture of 6.87% by weight of Sn in ITO, from the manufacturer of indium oxide and tin oxide, which are raw materials for ITO, the weight of tin %. The results are shown in Table 1 (see FIG. 3).

Example 4

In the same manner as in Example 1, 22.0 g of indium tin oxide, which was confirmed to contain indium and tin in a weight ratio of 89.9: 10.1, respectively, in ITO, was prepared from a manufacturer of indium oxide and tin oxide, , And the weight ratio of indium and tin contained in ITO was calculated using the weight percentage of tin. The results are shown in Table 2 below.

Example 5

In the same manner as in Example 1, except that 22.0 g of indium tin oxide, which was confirmed to contain In and Sn in the ITO by weight ratio of 90.3: 9.7, respectively, was prepared from a manufacturer of indium oxide and tin oxide, , And the weight ratio of indium and tin contained in ITO was calculated using the weight percentage of tin. The results are shown in Table 2 below.

Example 6

In the same manner as in Example 1, except that 22.0 g of indium tin oxide, which was confirmed to contain indium and tin in a weight ratio of 89.8: 10.2, respectively, in ITO, was prepared from a manufacturer of indium oxide and tin oxide, , And the weight ratio of indium and tin contained in ITO was calculated using the weight percentage of tin. The results are shown in Table 2 below.

Comparative Example 1

Indium and tin oxide, which are raw materials for ITO, were prepared from indium and tin oxide, respectively, and indium tin oxide (22.0 g), which was confirmed to contain indium and tin in ITO at a weight ratio of 89.9: 10.1, Weight ratio was measured, and the results are shown in Table 2 below.

Comparative Example 2

Indium and tin oxide, which are raw materials for ITO, were prepared from indium and tin oxide, respectively. Using indium tin oxide (22.0 g), which was confirmed to contain In and Sn in ITO at a weight ratio of 90.3: 9.7, Weight ratio was measured, and the results are shown in Table 2 below.

Comparative Example 3

In and Sn were prepared by using ICP from 22.0 g of indium tin oxide, which was confirmed to contain indium and tin in a weight ratio of 89.8: 10.2, respectively, in ITO, from indium oxide and tin oxide, which are raw materials for ITO. Weight ratio was measured, and the results are shown in Table 2 below.

Tin (Sn) (% by weight) Example 1 7.20 Example 2 7.13 Example 3 6.86

From the results of Table 1, it can be seen that the content by weight of tin measured by the methods of Examples 1 to 3 through the quantitative analysis method of the present invention agrees with the content of tin actually contained in ITO. That is, the results in Table 1 are interpreted as a result indicating the accuracy of the wet quantitative analysis according to the present invention. In particular, the methods of the above Examples 1 to 3 were once again verified by the Korean Chemical Fusion Test Institute and as shown in Figs. 1 to 3 (corresponding to Examples 1 to 3 respectively), the same tin % ≪ / RTI > by weight.

Indium (In) (weight ratio) Tin (Sn) (weight ratio) Example 4 89.9 10.1 Example 5 90.3 9.7 Example 6 89.8 10.2 Comparative Example 1 86.8 13.2 Comparative Example 2 87.7 12.3 Comparative Example 3 88.9 11.1

The results of Table 2 indicate that the weight ratio of indium calculated using the weight% content of tin measured by the wet quantitative analysis method according to the present invention is the same as that of indium and tin contained in the ITO sample used in the actual experiment As shown in Fig. This is interpreted as a result supporting the high reliability of the quantitative analysis method according to the present invention.

However, as shown in Table 2, it can be seen that the weight ratio of indium and tin measured by ICP shows a great difference from the actual value. This indicates that the content of the actually measured component is several to several tens It is interpreted that this is a result of a large error in the measurement using ICP because it is a unit of percent (%).

Therefore, the quantitative analysis using ICP is not suitable for the quantitative analysis of components having a unit of several to several tens of weight%, and the result of using the wet quantitative analysis method according to the present invention shows a very high degree of reliability This is the case.

Claims (1)

Dissolving indium tin oxide (ITO) in a powder state in hydrochloric acid to prepare a dissolution liquid, and filtering the dissolution liquid with a filter paper;
So as to have a 7 to 8, the pH value (pH) of the addition of aqueous ammonia to the dissolved solution to the indium hydroxide (In (OH) _3), and tin hydroxide (Sn (OH) ₄₎ to produce a metal hydroxide containing the metal Filtering the hydroxide with filter paper;
Washing the metal hydroxide with pure water;
Adding nitric acid solution to the washed metal hydroxide to produce meta-tartaric acid (H ₂ SnO ₃ );
Filtering the meta-tartaric acid with a filter paper;
Washing the meta-tartaric acid with a nitric acid solution;
The washed meta-tartaric acid is placed in a porcelain crucible, and a nitric acid solution is added thereto, and the weight of the remaining tin oxide (SnO ₂ ) is measured by heating at 900 to 1,100 ° C for 30 to 90 minutes. And
And calculating the weight% content of tin contained in the ITO by using the mass of the tin oxide measured by the following formula (1): < EMI ID =
[Equation 1]
Sn (%) = {(m ₁ x 0.7876) / m ₀ } x 100
Where m ₁ is the mass of the measured tin oxide and m ₀ is the mass of the indium tin oxide used as the analytical sample.

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