# US 9,435,006 B2 · Extraction agent for precious metals and rhenium, and extraction method for precious metals and rhenium using same

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- Number: US 9,435,006 B2
- Document ID: US9435006B2
- Status: Granted
- Kind: B2
- Application number: 14/779,908
- Filed: 2014-04-08
- Published: 2016-02-18
- Granted: 2016-09-06
- Earliest claimed: 2013-04-15
- Assignees: Kyushu University, National University Corporation; Sumitomo Metal Mining Co., Ltd.
- Applicants: Kyushu University, National University Corporation; Sumitomo Metal Mining Co., Ltd.
- Inventors: Masahiro Goto; Fukiko Kubota; Yuzo Baba
- Web page: https://patentgrep.com/patent/US9435006B2

## CPC

- C22B 11/04: {by wet processes (extraction of metal compounds by leaching in organic solutions C22B3/16; treatment or purification of solutions by liquid-liquid extraction C22B3/26)}
- C07C 237/06: having the nitrogen atoms of the carboxamide groups bound to hydrogen atoms or to acyclic carbon atoms
- C22B 3/20: Treatment or purification of solutions, e.g. obtained by leaching (C22B3/18 takes precedence)
- C22B 3/32: Carboxylic acids
- C22B 61/00: Obtaining metals not elsewhere provided for in this subclass (iron C21)
- Y02P 10/20: Recycling
- C22B: PRODUCTION AND REFINING OF METALS (electrolytic C25); PRETREATMENT OF RAW MATERIALS
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

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 α carbon as an amino acid. 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.

## Claims

### Claim 1

An extraction method for metals, the method comprising subjecting an acid solution containing one or more metals selected from precious metals and rhenium to solvent extraction with a metal extraction agent to extract the one or more metals selected from the precious metals and the rhenium from the acid solution,
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.

### Claim 2 (depends on 1)

The extraction method for metals according to claim 1, wherein the acid solution is subjected to the solvent extraction with the pH of the acid solution adjusted to 3.5 or lower.

### Claim 3 (depends on 1)

The extraction method for metals according to claim 1, wherein
the acid solution contains the one or more metals selected from the precious metals and the rhenium and at least one or more of manganese, nickel, and/or cobalt, and
the acid solution is subjected to the solvent extraction with the pH of the acid solution adjusted to 2.5 or lower.

### Claim 4 (depends on 1)

The extraction method according to claim 1, wherein the amide derivative is any one or more of glycinamide derivatives, histidinamide derivatives, lysinamide derivatives, aspartamide derivatives, and N-methylglycine derivatives.

### Claim 5

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.

### Claim 6 (depends on 5)

The extraction method according to claim 5, wherein the amide derivative is any one or more of glycinamide derivatives, histidinamide derivatives, lysinamide derivatives, aspartamide derivatives, and N-methylglycine derivatives.

### Claim 7

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.

### Claim 8 (depends on 7)

The extraction method according to claim 7, wherein the amide derivative is any one or more of glycinamide derivatives, histidinamide derivatives, lysinamide derivatives, aspartamide derivatives, and N-methylglycine derivatives.

### Claim 9

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.

### Claim 10 (depends on 9)

The extraction method according to claim 9, wherein the amide derivative is any one or more of glycinamide derivatives, histidinamide derivatives, lysinamide derivatives, aspartamide derivatives, and N-methylglycine derivatives.

### Claim 11

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.

### Claim 12 (depends on 11)

The extraction method according to claim 11, wherein the amide derivative is any one or more of glycinamide derivatives, histidinamide derivatives, lysinamide derivatives, aspartamide derivatives, and N-methylglycine derivatives.