EXTRACTION AGENT FOR PRECIOUS METALS AND RHENIUM, AND EXTRACTION METHOD FOR PRECIOUS METALS AND RHENIUM USING SAME

摘要

The present invention extracts precious metals from an acidic solution containing precious metals in an early and highly efficient manner. Provided is an extraction agent for precious metals that is represented by the general formula below. In the formula, R1 and R2 each represent the same alkyl group or different alkyl groups, R3 represents a hydrogen atom or an alkyl group, and R4 represents a hydrogen atom or a discretionary group that is not an amino group and that bonds to ± carbon as an amino acid. It is preferable that the general formula have a glycine unit, a histidine unit, a lysine unit, an aspartic acid unit, or an N-methylglycine unit. By subjecting an acidic solution containing precious metals to solvent extraction using the extraction agent for precious metals, a plurality of precious metals can be recovered all at once from a solution containing a large amount of various impurities. When recovering precious metals, it is preferable that the pH be set to 3.0 or less and further preferable that the pH be set to 2.5 or less. In addition, it is possible to separate palladium from other precious metals by performing reverse extraction using a second acidic solution having a lower pH than the original acidic solution.