The invention claimed is:
1. A method for isolating a valuable metal, wherein an acidic solution having an acidic pH and containing indium and gallium is subjected to solvent extraction by an extraction agent comprising an amide derivative represented by the following general formula (I) to isolate indium and gallium from the acidic solution:
wherein R 1 and R 2 each represent the same or different alkyl group,
the alkyl group is optionally a straight chain or a branched chain,
R 3 represents a hydrogen atom or an alkyl group, and
R 4 represents a hydrogen atom or any group other than an amino group which is bonded to an α chain as an amino acid.
2. The method for isolating a valuable metal according to claim 1 , wherein the amide derivative is any one or more of a glycine amide derivative, a histidine amide derivative, a lysine amide derivative, an aspartic acid amide derivative and a normal-methylglycine derivative.
3. The method for isolating a valuable metal according to claim 2 , wherein the amide derivative is the glycine amide derivative, and
the pH of the acidic solution is adjusted to a range of between 0.7 to 1.9.
4. The method for isolating a valuable metal according to claim 3 , wherein the acidic solution containing indium and gallium is a solution obtained by mixing sulfuric acid with a member containing indium and gallium and not containing cadmium and leaching indium and gallium from the member.
5. The method for isolating a valuable metal according to claim 3 , wherein, an acidic solution with a pH of 0.6 or less is mixed with the extraction agent which has extracted the indium, and, thereafter, the extraction agent and the acidic solution are separated to obtain the acidic solution containing the indium.
6. The method for isolating a valuable metal according to claim 2 ,
wherein the amide derivative is the histidine amide derivative, and
the pH of the acidic solution is adjusted to a range of between 0.7 to 3.0.
7. The method for isolating a valuable metal according to claim 6 , wherein, an acidic solution with a pH of 0.6 or less is mixed with the extraction agent which has extracted the indium, and, thereafter, the extraction agent and the acidic solution are separated to obtain the acidic solution containing the indium.
8. The method for isolating a valuable metal according to claim 6 , wherein the acidic solution containing indium and gallium is a solution obtained by mixing sulfuric acid with a member containing indium and gallium and not containing cadmium and leaching indium and gallium from the member.
9. The method for isolating a valuable metal according to claim 2 ,
wherein the amide derivative is the normal-methylglycine derivative, and
the pH of the acidic solution is adjusted to a range of between 0.7 to 2.3.
10. The method for isolating a valuable metal according to claim 9 , wherein, an acidic solution with a pH of 0.6 or less is mixed with the extraction agent which has extracted the indium, and, thereafter, the extraction agent and the acidic solution are separated to obtain the acidic solution containing the indium.
11. The method for isolating a valuable metal according to claim 9 , wherein the acidic solution containing indium and gallium is a solution obtained by mixing sulfuric acid with a member containing indium and gallium and not containing cadmium and leaching indium and gallium from the member.
12. The method for isolating a valuable metal according to claim 2 , wherein, an acidic solution with a pH of 0.6 or less is mixed with the extraction agent which has extracted the indium, and, thereafter, the extraction agent and the acidic solution are separated to obtain the acidic solution containing the indium.
13. The method for isolating a valuable metal according to claim 1 , wherein an acidic solution with a pH of 0.6 or less is mixed with the extraction agent which has extracted the indium and, thereafter, the extraction agent and the acidic solution are separated to obtain the acidic solution containing the indium.
14. The method for isolating a valuable metal according to claim 13 , further comprising mixing an acidic solution mixed with the extraction agent which has extracted the indium, and the extraction agent and the acidic solution are then separated to remove the gallium from the extraction agent.
15. The method for isolating a valuable metal according to claim 14 ,
wherein the amide derivative is a glycine amide derivative, and
the acidic solution has a pH of between 1.1 and 1.4.
16. The method for isolating a valuable metal according to claim 15 , wherein the acidic solution containing indium and gallium is a solution obtained by mixing sulfuric acid with a member containing indium and gallium and not containing cadmium and leaching indium and gallium from the member.
17. The method for isolating a valuable metal according to claim 14 ,
wherein the amide derivative is a histidine amide derivative, and
the acidic solution has a pH of between 1.5 and 1.8.
18. The method for isolating a valuable metal according to claim 14 ,
wherein the amide derivative is a normal-methylglycine derivative, and
the acidic solution has a pH of between 1.4 and 1.8.
19. The method for isolating a valuable metal according to claim 14 , wherein the acidic solution containing indium and gallium is a solution obtained by mixing sulfuric acid with a member containing indium and gallium and not containing cadmium and leaching indium and gallium from the member.
20. The method for isolating a valuable metal according to claim 13 , wherein the acidic solution containing indium and gallium is a solution obtained by mixing sulfuric acid with a member containing indium and gallium and not containing cadmium and leaching indium and gallium from the member.