| abstract |
In the present invention, nickel is selectively extracted from an acidic solution that contains a high concentration of manganese. This valuable metal extraction agent is represented by the general formula. In the formula, R 1 and R 2 are alkyl groups that may be the same or different, R 3 is a hydrogen atom or an alkyl group, and R 4 is a hydrogen atom or any group, other than an amino group, bonded to an a carbon atom of an amino acid. The general formula preferably has a glycine unit, a histidine unit, a lysine unit, an aspartic acid unit or a n-methylglycine unit. When extracting nickel by using this extraction agent, it is preferable to adjust the pH of the acidic solution to 2.3 to 5.5 inclusive. |