WO2016111571A1 - Method for collecting indium and tin using industrial waste - Google Patents

Abstract

The present invention relates to a method for collecting indium and tin using industrial waste and, more specifically, the method comprises: an inorganic acid mixing step for mixing an inorganic acid with industrial waste mixed with indium and tin; a tin precipitation step for mixing an ammonium sulfate powder with the mixture, which is mixed with the inorganic acid through the inorganic acid mixing step, to precipitate tin (II) sulfate; a tin separation step for separating tin(II) sulfate, which is precipitated through the tin precipitation step; and an indium collection step for mixing dilute hydrochloric acid and a zinc metal powder with the mixture, from which tin is separated through the tin separation step, to collect an indium sponge. The method for collecting indium and tin using industrial waste, comprising the above steps, can easily collect tin and indium, as high-priced metals, at high yield, which are contained in the industrial waste composed of metal sponge waste or sludge containing indium and tin. The collected indium and tin are convenient for metal retreatment.

Description

Recovery method of indium and tin using industrial waste

The present invention relates to a method for recovering indium and tin using industrial wastes, and more particularly, to recover indium and tin contained in industrial wastes consisting of metal sponge waste or sludge containing indium and tin in high yield. The present invention relates to a method for recovering indium and tin using industrial wastes.

Indium is used as a main raw material of the indium tin oxide target material required for the manufacturing process of the transparent conductive oxide film of the liquid crystal display device. With the rapid development of the display industry, the demand for indium and tin is continuously increasing.

Indium and tin in the display industry are used as core materials for transparent conductive oxides that are coated on glass substrates in the form of ITO to confirm conductivity and transparency. These ITO target materials are used not only for liquid crystal displays and plasma display panels but also for mobile communication devices. Demand is growing rapidly.

However, indium does not exist as a sole ore on the earth but is mainly contained in a small amount of zinc concentrate, and its reserves are very low in the world, and its rare value is high. Recently, due to the rapid increase in demand for electrode materials and marine light panels of display devices, It is expected that the time for exhaustion will be further advanced.

Efforts have been made to recover and recycle indium in order to solve the above problems, 1.A method for recovering indium by precipitating tin into metatartrate using nitric acid in an indium and tin mixed component, 2 A method of sedimentation and separation using hydroxides or carbonates of indium and tin using pH and a method of separating and recovering using an organic solvent have been studied. However, nitric acid is mixed in a component in which indium and tin are mixed as described above. The method of recovering indium by precipitating tin to meta-tartrate by using is complex because the meta-tartrate must be melted in alkali or acid treatment during the recovery of tin, and the post-treatment process and meta-tartrate and indium It is difficult to completely separate and the indium solution remains, causing loss of indium.

In addition, in the method of precipitating and separating the hydroxide or carbonate of indium and tin by using the pH as described above, the pH of tin hydroxide is 1 and the pH of hydroxide of indium is 2, so the difference in pH is different. It is difficult to control the process is small and there is a problem that complete separation is not made.

In addition, the method of separating and recovering using an organic solvent as in No. 3 uses a high concentration of an organic solvent, low extraction efficiency, complicated post-treatment processes such as stripping and replacement, and requires expensive facilities. There is a problem.

(Prior art document)

1. Korea Patent Registration No. 10-1220933 (2013.01.04).

2. Korean Patent Registration No. 10-1314067 (2013.09.26).

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for recovering indium and tin using industrial waste, which can easily recover indium and tin, which is an expensive metal contained in an industrial waste consisting of indium and tin, or an industrial waste consisting of sludge in high yield. will be.

Another object of the present invention is that tin can be easily recovered in a high yield in addition to indium, and indium and tin are not only recovered in a form in which metal material is easily processed, but also have a simple recovery process, thereby reducing treatment costs.

An object of the present invention is an inorganic acid mixing step of mixing the inorganic acid in the industrial waste mixed with indium and tin, the tin precipitation step of depositing the first tin sulfate by mixing ammonium sulfate powder in the mixture of the inorganic acid through the inorganic acid mixing step A tin separation step of separating the first tin sulfate precipitated through the tin precipitation step and an indium recovery step of recovering the indium sponge by mixing dilute hydrochloric acid and zinc metal powder in the tin separated mixture through the tin separation step. It is achieved by providing a method for recovering indium and tin using industrial waste, characterized in that made.

According to a preferred feature of the present invention, after the indium recovery step, the tin recovery step of dissolving the stannous sulfate separated through the tin separation step in dilute hydrochloric acid, and mixing the zinc powder to recover the tin sponge is further progressed Shall be.

According to a more preferred feature of the invention, the tin precipitation step is to be made by mixing 35 to 45 parts by weight of ammonium sulfate powder to 100 parts by weight of the mixture of the inorganic acid through the inorganic acid mixing step.

The method for recovering indium and tin using industrial wastes according to the present invention has an excellent effect of easily recovering indium, which is an expensive metal, at a high yield from an industrial waste composed of indium and tin metal sponge waste or sludge. .

In addition, tin can be easily recovered in a high yield in addition to indium, and indium and tin are not only recovered in a form in which metal materials are easily processed, but also have a simple recovery process, thereby reducing treatment costs.

1 is a flowchart illustrating a method of recovering indium and tin using industrial waste according to an embodiment of the present invention.

2 is a flow chart showing a method for recovering indium and tin using industrial waste according to another embodiment of the present invention.

** description of symbols for the main parts of the drawings **

S101; Inorganic Acid Mixing Step

S103; Precipitation Step

S105; Annotation Step

S107; Indium recovery stage

S109; Annotation Recovery Step

In the following, preferred embodiments of the present invention and the physical properties of each component will be described in detail, which is intended to explain in detail enough to be able to easily carry out the invention by one of ordinary skill in the art, This does not mean that the technical spirit and scope of the present invention is limited.

In the method of recovering indium and tin using the industrial wastes according to the present invention, the inorganic acid mixing step (S101) of mixing the inorganic acid with the industrial waste mixed with indium and tin (S101) to the mixture of the inorganic acid through the inorganic acid mixing step (S101) A tin precipitation step (S103) of precipitating the first tin sulfate by mixing ammonium sulfate powder (S103), a tin separation step (S105) of separating the first tin sulfate precipitated through the tin precipitation step (S103), and the tin separation step ( S105) is made of an indium recovery step (S107) of recovering the indium sponge by mixing dilute hydrochloric acid and zinc metal powder in the mixture separated tin.

The inorganic acid mixing step (S101) is a step of mixing the inorganic acid to the industrial waste mixed with indium and tin, mixing 2000 to 3000 parts by weight of the inorganic acid to 100 parts by weight of industrial waste consisting of metal sponge waste or sludge containing indium and tin The industrial waste is added to the reaction tank filled with an inorganic acid, followed by stirring to dissolve the acid.

The metal sponge used in the inorganic acid mixing step (S101) is a process of recovering indium from an indium hydroxide-containing cake, that is, tin by adding aluminum (Al) or zinc (Zn) metal having a tendency to ionize faster than indium or tin. In the form of a sponge in the reduced state generated in the process of substituting or recovering indium, it means a sponge containing indium and tin.

In this case, the inorganic acid is preferably made of hydrochloric acid having a concentration of 0.75 to 1 mole. If the concentration of the inorganic acid is less than 0.75 mole, the indium and tin containing metal sponge waste or indium or tin contained in the sludge is not leached. When the concentration of the inorganic acid exceeds 1 mole, although the indium or tin components contained in the metal sponge waste or the sludge are leached, the inorganic acid is used at a high concentration, thereby increasing the manufacturing cost.

The tin precipitation step (S103) is a step of precipitating tin tin sulfate by mixing ammonium sulfate powder in a mixture of the inorganic acid mixed through the inorganic acid mixing step (S101), the inorganic acid through the inorganic acid mixing step (S101) It is made by mixing 35 to 45 parts by weight of ammonium sulfate powder to 100 parts by weight of the mixed mixture. When the ammonium sulfate powder is mixed with the inorganic acid mixture through the inorganic acid mixing step (S101) as described above and stirred, the sulfuric acid of white crystals is mixed. The first tin is precipitated.

At this time, if the mixing amount of ammonium sulfate is less than 35 parts by weight, the tin contained in the mixture mixed with the inorganic acid through the inorganic acid mixing step can not be converted to all the tin tin sulfate.

The first tin sulfate precipitated through the tin precipitation step (S103) has a solubility in water at 18 to 20% at a temperature of 20 to 100 ° C., which is very low compared to the second tin sulfate, thereby improving the efficiency of the precipitation process. do.

The tin precipitation step is shown in Scheme 1 below.

<Scheme 1>

SnCl ₂ + (NH ₄ ) ₂ SO ₄ → SnSO ₄ + 2NH ₄ Cl

Meanwhile, tin is precipitated through the tin precipitation step (S103), and indium remains in the remaining mixture, which is present in the state of indium sulfate and is dissolved until saturation.

The process of allowing tin to precipitate and indium to exist in the remaining mixture is shown in Scheme 2 below.

<Scheme 2>

2InCl ₃ + 3 (NH ₄ ) ₂ SO ₄ → In ₂ (SO ₄ ) ₃ + 6NH ₄ Cl

The tin separation step (S105) is a step of separating the first tin sulfate precipitated through the tin precipitation step (S103), because the first tin sulfate precipitated through the tin precipitation step (S103) shows crystallinity It is preferable to separate using a rotary centrifugal filter.

The stannous sulfate precipitated through the tin separation step (S105) may be commercialized as it is, or dissolved in dilute hydrochloric acid, and then recovered with a tin sponge after mixing and stirring the zinc powder.

The indium recovery step (S107) is a step of recovering the indium sponge by mixing dilute hydrochloric acid and zinc metal powder in the tin separation mixture through the tin separation step (S105), tin through the tin separation step (S105) 100 parts by weight of diluted hydrochloric acid (0.5 to 2 moles) and 100 parts by weight of zinc powder are mixed with 100 parts by weight of the separated mixture, followed by stirring at a speed of 100 to 200 rpm.

As described above, after mixing the dilute hydrochloric acid and zinc powder in the tin-separated mixture through the tin separation step (S105), the indium sponge is recovered.

At this time, the indium recovery step (S107) may be made through a known method such as electrolytic refining method, hydrogen reduction method and alkali melting method, it is not a feature of the present invention.

Further, after the indium recovery step (S107), the tin recovery step (S109) of dissolving the stannous sulfate separated through the tin separation step (S105) in dilute hydrochloric acid and mixing the zinc powder to recover the tin sponge is Further, the tin recovery step (S109) is dissolved in 150 to 300 parts by weight of diluted hydrochloric acid (0.5 to 2 mol) in 100 parts by weight of stannous sulfate separated through the tin separation step (S105), zinc powder After mixing 100 parts by weight it consists of a process of stirring at a rate of 100 to 200rpm.

When the zinc powder is mixed and stirred in the tin recovery step (S109), tin sponges having a lower ionization tendency than zinc may be reduced and precipitated to recover tin.

At this time, the tin recovery step (S109) may be made through a known method such as electrolytic refining method, hydrogen reduction method and alkali melting method, it is not a feature of the present invention.

Hereinafter, a method for recovering indium and tin using industrial waste according to the present invention will be described with reference to Examples.

Example 1 Measurement of Concentration of Indium and Tin in Metal Sponge Wastes Generated After ITO Target Preparation

The concentrations of indium and tin contained in the metal sponge waste generated after the ITO target were measured and shown in Table 1 below.

TABLE 1

As shown in Table 1 above, the indium contained in the metal sponge waste generated after the ITO target production had a mass concentration of 2.0%, and the tin had a mass concentration of 35.0%.

In addition, the industrial waste used in the following examples will be used to use metal sponge waste having the concentration of indium and tin shown in Table 1.

Example 2 Acid Leaching Experiment of Metal Sponge Waste

50 g of the metal sponge waste was reacted with hydrochloric acid having concentrations of 0.25 mol, 0.5 mol and 0.75 mol, respectively, for 1 hour to measure leaching amounts of tin and indium, and the results are shown in Table 2 below.

TABLE 2

As shown in Table 2 above, most of the indium was dissolved in 0.25 mol of hydrochloric acid, and it can be seen that the solubility of tin, which is a metal having a small ionization tendency, increases rapidly as the concentration of hydrochloric acid increases.

In addition, it can be seen through Example 2 that indium is first leached through the injection of hydrochloric acid, and then leaching of tin occurs through the addition of an additional acid component.

In addition, as shown in Table 2, when the concentration of hydrochloric acid is 0.25 and 0.5 mol, the residual amount of indium or tin component is increased, it is preferable that the concentration of hydrochloric acid proceeds to 0.75 mol or more.

<Example 3> Separation of stannous sulfate in a mixed solution of tin and indium

1 g of hydrochloric acid having a concentration of 0.75 mole was mixed with 50 g of a metal sponge waste having a concentration of indium and tin as shown in Example 1, and an ammonium sulfate powder was mixed in a saturated amount and stirred to stannous sulphate. Was precipitated (primary), and stannous sulfate was precipitated, and the remaining filtrate was mixed with a saturated amount of ammonium sulfate powder and stirred to precipitate (tin) stannous sulfate (secondary). After the ammonium sulfate powder was mixed in a saturation amount and stirred to repeat the process of precipitation (third) of stannous sulfate, the precipitated stannous sulfate and stannous sulfate were precipitated and the remaining filtrate was separated and washed. The content of tin and indium contained in the prepared stannous sulfate and the filtrate is shown in Table 4 below.

TABLE 4

As shown in Table 4 above, the stannous sulfate does not contain any indium components, and since the indium components exist in the sulfate ion state in the filtrate, it can be seen that indium and tin have been completely separated.

In addition, in the case of mixing 98% concentrated sulfuric acid and ammonium sulfate powder, partial dissolution is performed, and indium and tin are not completely separated.

Example 4 Recovery of Indium Sponge

In Example 3, after the stannous sulfate was recovered in the first, second and third processes, and the remaining filtrates were combined, 200 parts by weight of dilute hydrochloric acid (1 mole) and 100 parts by weight of zinc powder were added to 100 parts by weight of the filtrate. After mixing, the mixture was stirred at a speed of 150 rpm to recover the zinc sponge, and the recovery amount and recovery rate are shown in Table 5 below.

TABLE 5

As shown in Table 5 above, it can be seen that the process of Example 4 of the present invention shows an excellent recovery rate for the indium contained in the metal sponge waste.

Example 5 Tin Sponge Recovery

In Example 3, 100 parts by weight of each of the first tin sulfate recovered in the first, second, and third portions was dissolved in 200 parts by weight of dilute hydrochloric acid (1 mol) to prepare a mixture, and the first tin sulfate 100 contained in the mixture. After mixing 100 parts by weight of zinc powder to parts by weight, the mixture was stirred at a speed of 150 rpm to recover the tin sponge, and the recovery amount is shown in Table 6 below.

TABLE 6

As shown in Table 6 above, the total amount of tin sponges recovered through the 1st to 3rd phases was 16.7 g, which is 95.4% of the tin component contained in the metal sponge waste containing 35% of the tin content shown in Example 1 Is recovered.

Therefore, the method for recovering indium and tin using the industrial wastes according to the present invention can easily recover indium, which is a high value metal, contained in an industrial waste composed of indium and tin metal sponge waste or sludge, In addition to indium, tin can be easily recovered in a high yield, and indium and tin can be recovered in a form in which metal materials are easily processed, and the recovery process of indium or tin is simplified, thereby reducing the processing cost.

The present invention relates to a method for recovering indium and tin using industrial wastes, and more particularly, to recover indium and tin contained in industrial wastes consisting of metal sponge waste or sludge containing indium and tin in high yield. It can be used for the recovery of indium and tin using industrial wastes.

Claims (2)

1. An inorganic acid mixing step of mixing the inorganic acid with the industrial waste mixed with indium and tin;

   A tin precipitation step of depositing stannous sulfate by mixing ammonium sulfate powder in the mixture of the inorganic acid through the inorganic acid mixing step;

   A tin separation step of separating the first tin sulfate precipitated through the tin precipitation step; And

   A method of recovering indium and tin using industrial waste, characterized in that consisting of; an indium recovery step of recovering the indium sponge by mixing dilute hydrochloric acid and zinc metal powder in the mixture is separated from the tin separation step.
2. The method according to claim 1,

   The tin precipitation step is a method for recovering indium and tin using industrial waste, characterized in that by mixing 35 to 45 parts by weight of ammonium sulfate powder to 100 parts by weight of the mixture of the inorganic acid through the inorganic acid mixing step.

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