Extraction agent for precious metals and rhenium, and extraction method for precious metals and rhenium using same

A palladium separation method, the method comprising:

• subjecting a first acid solution containing palladium and one or more other metals selected from precious metals and rhenium to solvent extraction with a metal extraction agent to extract the palladium and the one or more metals from the acid solution,
• separating the extraction agent in which the palladium and the other metals have been extracted from the acid solution,
• adding a second acid solution to the extraction agent in which the palladium and the other metals have been extracted to carry out back extraction, wherein the second acid solution has a pH lower than the pH of the first acid solution, and
• separating the extraction agent from the second acid solution to separate palladium from the other metals,
• wherein the metal extraction agent that comprises an amide derivative represented by the following general formula (I):
• wherein, R1 and R2 each represent the same or different alkyl groups;
• the alkyl group can be a straight chain or a branched chain;
• R3 represents a hydrogen atom or an alkyl group;
• and
• R4 represents a hydrogen atom or any group other than an amino group, which is bound to the α carbon as an amino acid.

A rhenium separation method, the method comprising:

• subjecting a first acid solution containing rhenium and one or more other metals selected from precious metals to solvent extraction with a metal extraction agent to extract the rhenium and the one or more metals from the acid solution,
• separating the extraction agent in which the rhenium and the other metals have been extracted from the acid solution,
• adding a second acid solution to the extraction agent in which the rhenium and the other metals have been extracted to carry out back extraction, wherein the second acid solution has a pH lower than the pH of the first acid solution, and
• separating the extraction agent from the second acid solution to separate the rhenium from the precious metals,
• wherein the metal extraction agent that comprises an amide derivative represented by the following general formula (I):
• wherein, R1 and R2 each represent the same or different alkyl groups;
• the alkyl group can be a straight chain or a branched chain;
• R3 represents a hydrogen atom or an alkyl group;
• and
• R4 represents a hydrogen atom or any group other than an amino group, which is bound to the α carbon as an amino acid.

A rhodium separation method, the method comprising subjecting an acid solution containing rhodium and at least one or more of platinum, osmium, iridium, and palladium to solvent extraction with a metal extraction agent with the pH of the acid solution adjusted to 2.5 or lower, to separate the rhodium from other metals,

• wherein the metal extraction agent that comprises an amide derivative represented by the following general formula (I):
• wherein, R1 and R2 each represent the same or different alkyl groups;
• the alkyl group can be a straight chain or a branched chain;
• R3 represents a hydrogen atom or an alkyl group;
• and
• R4 represents a hydrogen atom or any group other than an amino group, which is bound to the α carbon as an amino acid.

An iridium separation method, the method comprising:

• subjecting a first acid solution containing iridium and at least one or more of osmium and ruthenium to solvent extraction with a metal extraction agent,
• adding, thereto, a second acid solution to form a combined acid solution, wherein the pH of the combined acid solution is adjusted to 1.5 or lower,
• mixing the combined acid solution to carry out back extraction, and
• separating the extraction agent from the combined acid solution to separate the iridium from the osmium and the ruthenium,
• wherein the metal extraction agent that comprises an amide derivative represented by the following general formula (I):
• wherein, R1 and R2 each represent the same or different alkyl groups;
• the alkyl group can be a straight chain or a branched chain;
• R3 represents a hydrogen atom or an alkyl group;
• and
• R4 represents a hydrogen atom or any group other than an amino group, which is bound to the α carbon as an amino acid.