# US 5,350,717 A · Method for treating beta-spodumene ceramics

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 5,350,717 A
- Document ID: US5350717A
- Status: Granted
- Kind: A
- Application number: 08/072,547
- Filed: 1993-06-04
- Granted: 1994-09-27
- Earliest claimed: 1993-06-04
- Assignees: Corning Incorporated
- Inventors: J. Paul Day; David L. Hickman
- Web page: https://patentgrep.com/patent/US5350717A

## CPC

- C03C 21/007: {in gaseous phase}
- C03C: CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS

## Abstract

A vapor-phase method for treating a beta-spodumene ceramic article to achieve a substitution of exchangeable hydrogen ions for the lithium present in the beta-spodumene crystals, wherein a barrier between the ceramic article and the source of exchangeable hydrogen ions is maintained in order to prevent lithium contamination of the hydrogen ion source and to generate highly recoverable lithium salts, is provided.

## Claims

### Claim 1

A method for treating a beta-spodumene ceramic article which comprises the steps of:
providing a source of strong acid vapor;
positioning the article at a location spaced from the source;
contacting the article with circulating vapors of a strong acid while maintaining the article and the vapor at a substantially uniform temperature above the condensation temperature of the vapor, said contact being for a time at least sufficient to form a lithium salt bloom on the surface of the article; and
recovering the salt from the surface of the article without contaminating the source with the salt.

### Claim 2 (depends on 1)

A method in accordance with claim 1 wherein the source of strong acid vapor is a refluxing container of aqueous mineral acid, wherein the ceramic article is maintained at a temperature above the condensation temperature of the strong acid vapor, and wherein the ceramic is separated from the container by a salt barrier effective to prevent contamination of the liquid acid.

### Claim 3 (depends on 2)

A method in accordance with claim 2 wherein the strong acid vapor comprises sulfuric acid vapor.

### Claim 4 (depends on 3)

A method in accordance with claim 3 wherein the ceramic is provided in the form of a ceramic honeycomb.

### Claim 5

In the method for treating a beta-spodumene ceramic article wherein the ceramic is contacted with vapors of a refluxing strong acid to extract lithium salt therefrom, the improvement wherein:
the ceramic article is maintained at a substantially uniform temperature above the condensation temperature of the acid vapors; and
a salt barrier is interposed between the ceramic and the strong acid, whereby contamination of the strong acid with lithium salt is prevented.