# US 9,752,208 B2 · Extraction solvent for extracting metallic elements, method for producing same, and method for recovering metallic elements

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- Number: US 9,752,208 B2
- Document ID: US9752208B2
- Status: Granted
- Kind: B2
- Application number: 14/400,760
- Filed: 2012-05-16
- Published: 2015-08-06
- Granted: 2017-09-05
- Earliest claimed: 2012-05-16
- Applicants: Timothy W. Yarlott; Kokichi Hanaoka; Hiroshi Tanaka; Dick Wullaert; Edward E. Alexander
- Inventors: Timothy W. Yarlott; Kokichi Hanaoka; Hiroshi Tanaka; Dick Wullaert; Edward E. Alexander
- Web page: https://patentgrep.com/patent/US9752208B2

## CPC

- C22B 3/10: Hydrochloric acid {, other halogenated acids or salts thereof}
- C22B 7/007: {by acid leaching}
- C22B 7/02: Working-up flue dust
- 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)}
- C25B 1/00: Electrolytic production of inorganic compounds or non-metals
- C25B 1/26: Chlorine; Compounds thereof (by simultaneous production of alkali metal hydroxides and chlorine, oxyacids or salts of chlorine C25B1/34)
- Y02P 10/20: Recycling
- C22B: PRODUCTION AND REFINING OF METALS (electrolytic C25); PRETREATMENT OF RAW MATERIALS
- C25B: ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR (anodic or cathodic protection C23F13/00; single-crystal growth C30B)
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

The present invention provides an extraction solvent for extracting metallic elements that is characterized in that: the total concentration of chlorine (Cl2) and hypochlorous acid (HOCl) is from 20 to 1000 ppm; chlorine (Cl2) and hypochlorous acid (HOCl) are included at a molar ratio of 1:1 to 1:11; the oxidation-reduction potential is from 1100 to 1400 mV; and the pH is from 1.7 to 3.7. The present invention also provides a method for producing said extraction solvent, and a method for recovering metallic elements by using said extraction solvent.

## Claims

### Claim 1

An extraction solvent for extracting metallic elements, comprising:
a total concentration of chlorine (Cl2) and hypochlorous acid (HOCl) of from 20 to 1,000 ppm, and contains the chlorine (Cl2) and hypochlorous acid (HOCl) at a molar ratio of from 1:1 to 1:11;
a redox potential of from 1,100 to 1,400 mV; and
a pH of from 1.7 to 3.7.

### Claim 2 (depends on 1)

The extraction solvent according to claim 1, which further contains ozone by from 10 to 30 ppm.

### Claim 3 (depends on 1)

The extraction solvent according to claim 1, which further contains bromine, iodine or a salt thereof by from 0.01 to 0.1 mol/L.

### Claim 4 (depends on 1)

A method for producing the extraction solvent according to claim 1, comprising electrolyzing an electrolyte aqueous solution containing 0.01 to 0.5 mol/L of one or more electrolyte selected from sodium chloride, potassium chloride, calcium chloride and magnesium chloride at an electrical current value of from 0.5 to 5 A/min.L by using an apparatus for producing electrolyzed water.

### Claim 5 (depends on 4)

The method for producing an extraction solvent according to claim 4, wherein the apparatus for producing electrolyzed water is an apparatus for producing electrolyzed water equipped with a diaphragm electrolytic cell.

### Claim 6 (depends on 4)

The method for producing an extraction solvent according to claim 4, wherein the apparatus for producing electrolyzed water is an apparatus for producing electrolyzed water having a diaphragmless electrolytic cell.

### Claim 7 (depends on 1)

A method for recovering metallic elements, comprising the steps of:
bringing the extraction solvent according to claim 1 into contact with a substance to be subjected to extraction containing metallic elements to extract the metallic elements from the subject to thereby give a metallic element solution, and
recovering the metallic elements from the metallic element solution.

### Claim 8 (depends on 7)

The method for recovering metallic elements according to claim 7, wherein the metallic elements are metallic elements belonging to Group 1, Group 2, Group 5, Group 6, Group 7, Group 8, Group 13 and Group 14.

### Claim 9 (depends on 7)

The method for recovering metallic elements according to claim 7, wherein the metallic elements are gold, silver or platinum-group elements.