# US 2014/0154155 A1 · Refining methods and agents for rare earth production

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- Number: US 2014/0154155 A1
- Document ID: US20140154155A1
- Status: Published application
- Kind: A1
- Application number: 14/096,129
- Filed: 2013-12-04
- Published: 2014-06-05
- Earliest claimed: 2012-12-04
- Assignees: Lixivia, Inc.
- Applicants: Lixivia, Inc.
- Inventors: Michael D. Wyrsta; Zachary J.A. Komon
- Web page: https://patentgrep.com/patent/US20140154155A1

## CPC

- C22B 59/00: Obtaining rare earth metals
- C07C 215/08: with only one hydroxy group and one amino group bound to the carbon skeleton
- C22B 3/14: containing ammonia or ammonium salts
- C22B 3/1608: {Leaching with acyclic or carbocyclic agents}
- C22B 3/1625: {with amines (amino acids C22B3/165)}
- C22B 3/1666: {Leaching with heterocyclic compounds}
- C22B 3/28: Amines
- C22B 3/44: by chemical processes (treatment or purification of solutions by liquid-liquid extraction C22B3/26, by ion-exchange extraction C22B3/42)
- 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

Hydrometallurgical systems, methods, and compositions are described in which organic amine-based lixiviants are utilized in the selective recovery of rare earth elements. The lixiviant can be regenerated in situ, permitting the organic amine to be used in substoichiometric amounts.

## Claims

### Claim 1

A method for extracting a rare earth element, comprising:
contacting a sample comprising a first rare earth element with a first lixiviant, the first lixiviant comprising a first organic amine cation and a first counterion;
forming a first supernatant comprising an uncharged first organic amine, and a first complex comprising a cation of the first rare earth element and the first counterion;
transferring the first rare earth element cation from the first supernatant; and
regenerating the first organic amine cation,
wherein the first organic amine cation is provided in substochiometric amounts relative to the first rare earth element.

### Claim 2 (depends on 1)

The method of claim 1, wherein the first organic amine cation is regenerated by the addition of an acid form of the first counterion while the sample is in contact with the first lixiviant.

### Claim 3 (depends on 1)

The method of claim 1, further comprising the step of removing the first complex from the supernatant.

### Claim 4 (depends on 3)

The method of claim 3, wherein the first complex is removed by forming a precipitate.

### Claim 5 (depends on 1)

The method of claim 1, wherein the first organic amine has a pKa of 8 to 14.

### Claim 6 (depends on 5)

The method of claim 5, wherein the first organic amine cation is obtained from a biological source.

### Claim 7 (depends on 1)

The method of claim 1, wherein the first counterion has a pKa of 1 to 6.

### Claim 8 (depends on 1)

The method of claim 1, wherein the first lixiviant is formed by adding an acid to the uncharged first organic amine in the presence of the sample.

### Claim 9 (depends on 1)

The method of claim 1, wherein the first rare earth element cation is transferred by forming a precipitate.

### Claim 10 (depends on 1)

The method of claim 1, wherein the sample further comprises a second rare earth element, and further comprising the steps of:
transferring the first supernatant from the sample to form a depleted sample;
contacting the depleted sample with a second lixiviant, the second lixiviant comprising a second organic amine cation and a second counterion;
forming a second supernatant comprising an uncharged second organic amine and a second complex comprising a second rare earth element cation and the second counterion
transferring the second rare earth element cation from the second supernatant; and,
regenerating the second organic amine cation.

### Claim 11 (depends on 10)

The method of claim 10, wherein the second organic amine cation is regenerated by the addition of an acid form of the second counterion while the sample is in contact with the second lixiviant.

### Claim 12 (depends on 10)

The method of claim 10, wherein the second rare earth element cation is transferred by forming a precipitate.

### Claim 13

A method for extracting rare earth elements, comprising:
contacting a sample comprising a first rare earth element and a second rare earth element with a lixiviant, the lixiviant comprising an first organic amine cation, a second organic amine cation, and a counterion;
forming a first supernatant comprising an uncharged first organic amine, an uncharged second organic amine, a first complex comprising a first rare earth metal cation and the counterion, and a second complex comprising a second rare earth metal cation and the counterion;
transferring the first rare earth metal cation from the first supernatant to form a second supernatant;
transferring the second rare earth metal cation from the second supernatant and,
regenerating the first organic amine cation and the second organic amine cation from the second supernatant,
wherein the first organic amine cation is provided in substochiometric amounts relative to the first rare earth metal.

### Claim 14 (depends on 13)

The method of claim 13, wherein the first organic amine has a pKa of 8 to 14.

### Claim 15 (depends on 13)

The method of claim 13, wherein the second organic amine has a pKa of 8 to 14.

### Claim 16 (depends on 13)

The method of claim 13, wherein the first organic amine cation and the second organic amine cation are the same species.

### Claim 17 (depends on 13)

The method of claim 13 wherein the first organic amine cation and the second organic amine cation are different species.

### Claim 18 (depends on 13)

The method of claim 13, wherein the first organic amine cation is regenerated by the addition of an acid form of the counterion while the sample is in contact with the lixiviant.

### Claim 19 (depends on 13)

The method of claim 13, wherein the first rare earth element is transferred from the first supernatant by the addition of a first precipitant.

### Claim 20 (depends on 19)

The method of claim 19, wherein the first precipitant is a base comprising a hydroxide.

### Claim 21 (depends on 19)

The method of claim 19, wherein the second rare earth element is transferred from the second supernatant by the addition of a second precipitant.

### Claim 22 (depends on 21)

The method of claim 21, wherein the first precipitant and the second precipitant are the same species applied to give a first concentration of the species in the first supernatant and a second concentration of the second species in the second supernatant.

### Claim 23

A lixiviant for extracting rare earth elements, comprising:
an organic amine cation; and,
a counterion;
wherein the organic amine is formulated to transfer the counterion to an insoluble rare earth salt to form an uncharged organic amine, and wherein uncharged organic amine is formulated to react with an acid form of the counterion to regenerate the organic amine cation.

### Claim 24 (depends on 23)

The lixiviant of claim 23, wherein the organic amine has a vapor pressure less than 1% that of ammonia.

### Claim 25 (depends on 23)

The lixiviant of claim 23, wherein the organic amine has a vapor pressure less than 0.1% that of ammonia.

### Claim 26 (depends on 23)

The lixiviant of claim 23, wherein the organic amine has a pKa of 8 to 14.

### Claim 27 (depends on 23)

The lixiviant of claim 23, wherein the organic amine cation is obtained from a biological source.

### Claim 28 (depends on 23)

The lixiviant of claim 23, wherein the counterion has a pKa of 1 to 6.