JPS61136918A - Separation of indium and gallium - Google Patents

Abstract

PURPOSE:To extract easily and selectively In and Ga from an aq. sulfuric acid soln. by submitting the aq. sulfuric acid soln. contg. In and Ga to extraction with use of a soln. in an org. solvent contg. alkylphenylphosphoric ester. CONSTITUTION:An aq. sulfuric acid soln. contg. In and Ga is subjected to extrac tion at >=0.5mol/l sulfuric acid concn. by using a soln. in an org. solvent contg. alkylphenylphosphoric ester, and separated into an org. phase contg. In and an aq. phase contg. Ga. Then the aq. phase thus obtained contg. Ga is subjected to extraction at <0.5mol/l sulfuric acid concn. by using an soln. in an org. solvent contg. alkylphenylphophpric ester to transfer Ga into the org. soln. The In and Ga respectively transferred into each org. phase are easily stripped by hydrochloric acid, sulfuric acid, or a sodium hydroxide soln.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for separating indium and gallium from an aqueous sulfuric acid solution containing indium and gallium by an extraction method.

In the zinc smelting process, the smelting residue contains trace amounts of indium and gallium as an aqueous sulfuric acid solution.

On the other hand, indium and gallium.

Demand for indium as a semiconductor element has increased, and in recent years there has been a demand for the development of a method for separating and recovering indium and gallium from the aqueous sulfuric acid solution.

The purpose of the present invention is to separate and recover indium and gallium in a high yield from an aqueous sulfuric acid solution containing indium and gallium. This is a method of extracting, separating, and recovering gallium.

According to research conducted by the present inventors, it has been found that alkylphenyl phosphate esters exhibit excellent selective extraction and separation effects for extracting and separating gallium and indium from aqueous sulfuric acid solutions.

The extractant used in the present invention is a solution of an alkylphenyl phosphate ester dissolved in a suitable organic solvent. In this case, the alkylphenyl phosphate ester includes mono- and diesters, which are represented by the following general formula.

(In the above formula, nl and R2 represent an alkyl group, usually a higher alkyl group having 8 or more carbon atoms, preferably 8 to 10 carbon atoms. ph represents a phenylene group) The above general formula (1) used in the present invention The alkylphenyl phosphate esters represented by ) and (If) can be used alone or preferably in the form of a mixture.

Furthermore, as the organic solvent for dissolving the alkyl phenyl phosphate ester, it is preferable to use one that is stable against sulfuric acid, for example, a solvent containing aromatic hydrocarbons such as benzene, toluene, and xylene. The concentration of alkylphenyl phosphate in the extractant is preferably selected within the range of 1 to 5% by weight. If the concentration of alkylphenyl phosphate is less than 1% by weight, the ability to extract gallium and indium will decrease. On the other hand,
If it exceeds 5% by weight, it is not preferable because it causes problems such as poor phase separation of the extracted product and a value close to the solubility limit of the alkylphenyl phosphate ester.

In the present invention, an aqueous sulfuric acid solution containing indium and gallium is first extracted using an organic solvent solution containing the alkyl phenyl phosphate ester (hereinafter referred to as an extractant). Under the sulfuric acid concentration conditions such as 0.5 mol IQ or more, preferably 1 to 2 mol/Ω, indium in the sulfuric acid aqueous solution is selectively transferred to the extractant, and indium is contained. An organic phase (extractant phase) and an aqueous phase containing gallium (
sulfuric acid aqueous solution phase). The gallium-containing aqueous phase thus obtained is then extracted again using an extractant, in which case the sulfuric acid concentration in the aqueous phase is less than 0.5 mol/l, preferably 0. .1~0.01
Defined by molar IQ. Under such sulfuric acid concentration conditions, gallium contained in the aqueous phase is transferred to the extractant in good yield.

The respective indium and gallium transferred to each organic phase (extractant phase) as described above can then be easily back-extracted with hydrochloric acid, sulfuric acid, or sodium hydroxide solution.

Next, the present invention will be explained in more detail with reference to examples.

Example 1 1 mol/l sulfuric acid aqueous solution containing indium and gallium 5
After mixing 0mM and 50mQ of a benzene solution of 2.5% by weight octylphenyl phosphate ester (a mixture of monoester and diester in a weight ratio of 1:1, the same applies hereinafter), the organic phase and the aqueous phase were mixed. separated. The organic phase was back-extracted using hydrochloric acid to recover indium. Next, the aqueous phase after extraction was diluted 10 times.

2. Make a 0.1 mol IQ sulfuric acid aqueous solution and add 5.
After mixing 5% by weight of a benzene solution of octylphenyl phosphate in 50% carbon dioxide, the mixture was separated into an organic phase and an aqueous phase.

The organic phase was back-extracted using sodium hydroxide solution to recover gallium. The results are shown in Table 1.

Table 1 Example 2 2 mol/Ω sulfuric acid aqueous solution containing indium and gallium 5
After mixing 0 ■Ω and a benzene solution of 2.5% by weight octylphenyl phosphate 50+sQ.

It was separated into an organic phase and an aqueous phase. The organic phase was back-extracted using hydrochloric acid to recover indium.Then, the aqueous phase after extraction was
Diluted to 0 times to make a 0.2 mol IQ sulfuric acid aqueous solution, mixed 50 ml of the sulfuric acid aqueous solution with 50 ml of a benzene solution of 2.5% by weight octylphenyl phosphate, and then mixed it into the organic phase and the aqueous phase. separated. The organic phase was back-extracted using sodium hydroxide solution to recover gallium. The results are shown in Table 2.

Table 2 Example 3 A 1 mol 10 sulfuric acid aqueous solution containing indium and gallium,
A benzene solution of 4% by weight octylphenyl phosphate ester was mixed with 50% of the solution, and then separated into an organic phase and an aqueous phase. The organic phase was back-extracted using hydrochloric acid to recover indium. The aqueous phase after extraction was diluted 10 times to make a 0.1 mol IQ sulfuric acid aqueous solution, and after mixing 50 tan and 50 ra Q of a benzene solution of 4% octylphenyl phosphate, the organic phase and the aqueous phase were diluted. separated. The organic phase was back-extracted using sodium hydroxide solution to recover gallium.

The results are shown in Table 3.

Table 3

Claims (2)

[Claims] (1) In separating indium and gallium from an aqueous sulfuric acid solution containing indium and gallium, the aqueous solution is extracted using an organic solvent solution containing an alkyl phenyl phosphate under conditions of a sulfuric acid concentration of 0.5 mol/l or more. A method for separating indium and gallium, the method comprising separating indium and gallium into an organic phase containing indium and an aqueous phase containing gallium. (2) To separate indium and gallium from an aqueous sulfuric acid solution containing indium and gallium, extract the aqueous solution with an organic solvent solution containing an alkyl phenyl phosphate under conditions of a sulfuric acid concentration of 0.5 mol/l or more. , separated into an organic phase containing indium and an aqueous phase containing gallium, and then extracting the aqueous phase using an organic solvent solution containing an alkyl phenyl phosphate under conditions of a sulfuric acid concentration of less than 0.5 mol/l. and transferring gallium to the organic solvent solution.