JPS606896B2 - Method for back extraction of indium in organic solvent phase - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for back-extracting and recovering indium from an organic solvent phase containing indium.

In recent years, with the practical use of solvent extraction methods in smelting, various methods for recovering indium by solvent extraction have been proposed. For example, indium is selectively extracted by contacting an aqueous solution containing indium ions with an organic solvent containing a mixture of trialkyl phosphoric acid and monoalkyl phosphoric acid or dialkyl phosphoric acid as an extractant; A method of back-extracting indium from the organic solvent phase by bringing the organic solvent phase into contact with a hydrochloric acid aqueous solution (Japanese Patent Publication No. 55
-148735), indium is extracted from an aqueous solution containing indium using an organic solvent containing tributyl phosphate (TBP) as an extractant, and then the indium in the obtained organic solvent phase is inverted using water as an extractant. Extraction method and extraction of indium from an aqueous solution containing indium using a tertiary fatty acid as an ion exchange solution,
A method of back-extracting the indium in the resulting solvent using hydrochloric acid as an extractant [Journal of the Japan Mining Association, Vol.
93, NO. 1070 (1977-4), pages 323 to 325], indium is extracted from an acidic sulfuric acid solution containing indium using an organic solvent containing di-2-ethylhexyl phosphate as an extractant, and then the resulting organic A method of back-extracting indium in the solvent phase using hydrochloric acid or sulfuric acid (Taru Kai No. 55-148736) and a method of extracting an acidic sulfuric acid solution containing indium using mono-2-ethylhexyl ester of 2-ethylhexylphosphonic acid as an extractant. A method has been proposed in which indium is extracted using an organic solvent containing organic solvent, and then indium in the obtained organic solvent phase is back-extracted using hydrochloric acid or sulfuric acid.

That is, as mentioned above, indium is selectively extracted from an aqueous solution containing indium using an organic solvent containing various extractants, and then indium in the obtained organic solvent phase is back-extracted using hydrochloric acid, sulfuric acid, or water. Until now, methods of recovering indium are known which consist of: In the present invention, when back-extracting indium from an indium-containing organic solvent phase obtained by extracting indium using an organic solvent containing various extractants as described above, hydrochloric acid and
It is characterized in that it is used as an extractant for the above-mentioned back extraction containing an aqueous solution containing a chloride of a metal less base than indium.

As mentioned above, when back-extracting indium from an organic solvent phase containing indium, it is known that hydrochloric acid is used as an extractant, but if an aqueous solution containing hydrochloric acid and a chloride of the above metal is used as an extractant, Advantages can be seen in that the amount of hydrochloric acid used for back extraction can be saved, that a solution after back extraction with a high indium concentration can be obtained, and that the chlorides of the metals mentioned above can be recycled and reused.

The present invention will be explained in detail below.

The indium-containing organic solvent phase from which indium is back-extracted in the present invention can be obtained by contacting an indium-containing aqueous solution with an organic solvent containing an extractant capable of selectively extracting indium from the aqueous solution. It will be done.

The extractants used here include various conventionally known organic phosphoric acids, organic phosphonic acids, organic phosphinic acids, trialkyl acetic acids, and di-2-ethylhexyl phosphoric acid ester (D2EHPA), 2- Ethylhexylphosphonic acid mono-2-ethylhexyl ester, tributyl phosphate (TBP), tertiary fatty acids such as verast
icacid (product name of Shell Chemical Co., Ltd., C, Niji 2, CO
OH), etc. may be exemplified. These extractants can be used alone or as a mixture of two or more, and are generally used after being diluted with natural oil such as kerosene, alcohol, or the like. In the present invention, an indium-containing organic solvent obtained by contacting an acidic aqueous solution of indium obtained by leaching an indium raw material with a mineral acid such as sulfuric acid with an organic solvent containing an extractant as described above by a conventional method, Indium in the organic solvent phase is back-extracted by contacting with an aqueous solution containing hydrochloric acid and a chloride of a metal less base than indium.

Here, chlorides of metals less base than indium used as extractants for the back extraction of indium in the organic solvent phase include chlorides of alkali metals such as sodium chloride and potassium chloride, and chlorides of alkali metals such as magnesium chloride and calcium chloride. An example may be chloride. In the present invention, the chloride of a metal less base than indium is used as the chloride because it does not interfere with the operation of recovering indium (in the form of Inc13) in the solution after back extraction by replacing it with zinc or aluminum in the next step. It is for the purpose of doing.

The concentration of hydrochloric acid in the aqueous solution used as an extractant in the back extraction according to the present invention is preferably about 0.5 to about 100 ml, and the higher the concentration of the metal chloride, the better, and it can be increased to near saturated solubility.

In addition, the contact ratio (0/A) between the organic solvent phase (0) and the extractant aqueous solution phase (A) during back extraction is not particularly limited, but is 1/A.
The contact temperature is preferably in the range of 1 to 10/1, and it is effective if the contact temperature is overflowing, but room temperature is also sufficient. A suitable contact time is 0.5 to 10 minutes. When indium in the organic solvent phase is back-extracted according to the present invention, indium can be recovered in the form of Inc13 in the solution after back-extraction, and metal chlorides in the solution after extraction are helicycled in the back-extraction process after recovering indium. Can be reused as extractant for back extraction. The attached drawings show the results of a test on the effect of containing a metal chloride in the extractant on the concentration of indium extracted into the solution after back extraction in the back extraction according to the present invention.

The test was conducted according to the following procedure.

Indium was extracted from an indium-containing aqueous sulfuric acid solution using a 4% by volume kerosene solution of 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester to obtain an organic solvent phase containing indium. For the organic solvent phase (0), aqueous hydrochloric acid solutions of various concentrations containing sodium chloride at a concentration of 100/A were used as extractants A, and aqueous hydrochloric acid solutions of various concentrations containing no sodium chloride were used as extractants A/A=100'. /20' of contact, back extraction was performed for 1 minute at 20° C. under a shaking moat, and changes in indium concentration in the resulting back-extracted liquids were measured.

In addition, the hydrochloric acid concentration in the back-extraction solution is expressed in the figure by the measured value of the hydrochloric acid concentration in the solution after back-extraction (horizontal axis of the figure).

As can be seen in the accompanying drawings, when an aqueous hydrochloric acid solution containing sodium chloride (NaCI) is used as a back-extracting agent, the efficiency of back-extracting indium is significantly higher than when using an aqueous solution of hydrochloric acid alone.

As described above, according to the present invention, when back-extracting indium from an organic solvent phase containing indium, indium can be back-extracted at a high concentration, and the metal chloride added to the extractant can be back-extracted. Since it can be recycled and reused in the process, it has the advantage of saving on the amount of hydrochloric acid feces.

The present invention will be described in more detail below by way of examples.

Example 1 Indium obtained by selectively extracting indium from an indium-containing aqueous solution using 100 parts of an organic solvent prepared by diluting 40 parts of mono-2-ethylhexyl ester of 2-ethylhexylsulfonic acid with 60 parts of kerosene was extracted with 14. After 8 days, the organic solvent phase contained therein was back-extracted by the following procedure.

Extractant used for back extraction: {i) Aqueous solution containing 72 hours/hour of hydrochloric acid and 126 hours/hour of potassium chloride (KCI).

[o} Hydrochloric acid for 72 hours/day and calcium chloride (C
An aqueous solution containing 95% of aC12).

Hydrochloric acid was added for 72 hours/day and magnesium chloride (MgC
12) Aqueous solution containing 829/s. Above organic solvent phase○
and the above {i),'. } and each extractant phase A of ○/
Contact was carried out for 1 minute at room temperature with shaking at a ratio of 1/20 with an A ratio of 100. The results are shown in Table 1 below.
For comparison, the results of contacting the above organic solvent phase with an aqueous solution containing 72%/only hydrochloric acid as an extractant are also shown in Table 1 below.

Table 1 Note) The partition coefficient in the table indicates the following ratio: o Indium concentration in organic solvent phase/indium concentration in reverse extraction phase.

As seen in the table above, KC1, CaC12 and Mg
It can be seen that when an aqueous hydrochloric acid solution containing C12 is used as an extractant, the back-extracted concentration of indium is higher than when only a conventional aqueous hydrochloric acid solution is used.

Example 2 Indium was obtained by selectively extracting indium from an indium-containing aqueous solution using each of the following extractants.
Each organic solvent phase containing 100% of hydrochloric acid and 1009% of sodium chloride (NaCI) was immersed in an aqueous solution containing 72% of hydrochloric acid and 100% of sodium chloride (NaCI) at a ratio of 100% and 20% at room temperature for 10%. Indium was back-extracted from each organic solvent phase by contacting for a minute.

Composition of the organic solvent phase: K} 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester 40 μl and tributyl phosphoric acid 10 μl diluted with 50 μl of kerosene (total amount: 100 μl).

0} Diluted 40 parts of monoethylhexyl ester 2-ethylhexylphosphonic acid with 50 parts of kerosene and 10 parts of tridecyl alcohol (total volume of 100 parts). di-2-ethylhexyl monophosphate (D is HPA) 4
0 chicken diluted with 60% kerosene (total amount 100M)
.

Z with an OD of HPAH 40 and tributyl phosphate 10% diluted with 50% kerosene (total amount 100%).

Hata D diluted 40 HPA with 50 kerosene and 10 tridecyl alcohol (total volume 100').
The results of the above back extraction are shown in Table 2 below. For comparison, Table 2 also shows the results of back extraction using an aqueous solution containing 72 tanosonomi of hydrochloric acid. Table 2 Note: The distribution coefficients in the table have the same meanings as in Table 1.

As seen in the above table, regardless of the type of extractant used for extraction of the organic solvent phase, when a hydrochloric acid aqueous solution containing NaCI is used to back-extract indium in the organic solvent phase, when an aqueous solution containing only hydrochloric acid is used It can be seen that the indium concentration in the liquid after back extraction is higher than that in the sample.

[Brief explanation of the drawing]

The attached drawings show the results of back-extraction of indium from an organic solvent phase containing indium at various concentrations of hydrochloric acid when using an aqueous solution of hydrochloric acid containing sodium chloride as the extractant and when using an aqueous solution of only hydrochloric acid. Indium (
ln) This shows the change in concentration.

Claims (1)

[Scope of Claims] 1. In a method for back-extracting indium from an organic solvent phase containing indium using an extractant, an aqueous solution containing hydrochloric acid and a chloride of a metal less base than indium is used as the extractant. A method for back-extracting indium from the above-mentioned organic solvent phase. 2. The method according to claim 1, wherein the metal chloride is an alkali metal chloride. 3. The method according to claim 1, wherein the metal chloride is an alkaline earth metal chloride.