# US 5,711,019 A · Method for treating electrolyte to remove Li.sub.2 O

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- Number: US 5,711,019 A
- Document ID: US5711019A
- Status: Granted
- Kind: A
- Application number: 08/594,974
- Filed: 1996-01-31
- Granted: 1998-01-20
- Earliest claimed: 1996-01-31
- Assignees: The United States of America as represented by the United States Department of Energy
- Inventors: Zygmunt Tomczuk; William E. Miller; Gerald K. Johnson; James L. Willit
- Web page: https://patentgrep.com/patent/US5711019A

## CPC

- A62D 3/37: by reduction, e.g. hydrogenation
- C01D 3/14: Purification
- C01D 15/00: Lithium compounds
- A62D 2101/43: containing heavy metals, in the bonded or free state
- A62D: CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
- C01D: COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM (metal hydrides {monoborane, diborane or addition complexes thereof} C01B6/00; salts of oxyacids of halogens C01B11/00; peroxides, salts of peroxyacids C01B15/00; sulfides C01B17/22; thiosulfates, dithionites, polythionates C01B17/64; compounds containing selenium or tellurium C01B19/00; binary compounds of nitrogen with metals C01B21/06; azides C01B21/08; {compounds other than ammonia and cyanogen, containing nitrogen and other non-metals C01B21/082}; metal amides C01B21/092; nitrites C01B21/50; phosphides C01B21/50; {compounds of noble gases C01B23/0005}; phosphides C01B25/08; salts of oxyacids of phosphorus C01B25/16; carbides C01B32/90; compounds containing silicon C01B33/00; compounds containing boron C01B35/00; cyanides C01C3/08; salts of cyanic acid C01C3/14; salts of cyanamide C01C3/16; thiocyanates C01C3/20)

## Abstract

A method of removing Li.sub.2 O present in an electrolyte predominantly of LiCl and KCl. The electrolyte is heated to a temperature not less than about 500.degree. C. and then Al is introduced into the electrolyte in an amount in excess of the stoichiometric amount needed to convert the Li.sub.2 O to a Li-Al alloy and lithium aluminate salt. The salt and aluminum are maintained in contact with agitation for a time sufficient to convert the Li.sub.2 O.

## Claims

### Claim 1

A method of removing Li.sub.2 O present in a halide salt, comprising contacting the salt with Al for a time sufficient to convert Li.sub.2 O to a Li-Al alloy and a lithium-aluminate salt.

### Claim 2 (depends on 1)

The method of claim 1 wherein aluminum is present in an amount greater than the stoichiometric amount needed to convert the lithium oxide present to lithium aluminate and a lithium-aluminum alloy.

### Claim 3 (depends on 1)

The method of claim 1 wherein the salt and the aluminum are agitated during the reaction.

### Claim 4 (depends on 1)

The method of claim 1 wherein the salt is predominately a mixture of lithium and potassium chloride.

### Claim 5 (depends on 1)

The method of claim 1 and further including adding lithium metal to the salt and aluminum mixture.

### Claim 6 (depends on 1)

The method of claim 1 wherein the salt and aluminum are in contact for a time ranging from about 2 hours to about 10 hours.

### Claim 7 (depends on 1)

The method of claim 1 wherein the salt and aluminum are in contact for time in the range of from about 5 hours to about 10 hours and the temperature is maintained not less than about 500.degree. C.

### Claim 8

A method of removing Li.sub.2 O present in an electrolyte predominantly of LiCl and KCl comprising maintaining the electrolyte at a temperature not less than about 500.degree. C., introducing Al into the electrolyte in an amount in excess of the stoichiometric amount needed to convert the Li.sub.2 O to a Li-Al alloy and lithium aluminate salt and maintaining salt and aluminum in contact for a time sufficient to convert the Li.sub.2 O.

### Claim 9 (depends on 8)

The method of claim 8, wherein the electrolyte and Al are agitated during conversion of the Li.sub.2 O.

### Claim 10 (depends on 9)

The method of claim 9, wherein the time is in the range of from about 2 hours to about 10 hours.

### Claim 11 (depends on 9)

The method of claim 9, wherein the time is in the range of from about 4 hours to about 10 hours.

### Claim 12 (depends on 11)

The method of claim 11, wherein the temperature is maintained not less than about 600.degree. C.

### Claim 13 (depends on 4)

The method of claim 4 wherein the salt is heated to a temperature of about 500.degree. C. prior to contacting the aluminum.

### Claim 14 (depends on 1)

The method of claim 1 wherein the salt is predominately lithium chloride.

### Claim 15 (depends on 14)

The method of claim 14 wherein the salt is heated to a temperature of about 630.degree. C. prior to contacting the aluminum.

### Claim 16 (depends on 1)

The method of claim 1 wherein the aluminum is in the form of finely divided aluminum particles.