# US 4,395,384 A · Process for treating zircon

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- Number: US 4,395,384 A
- Document ID: US4395384A
- Status: Granted
- Kind: A
- Application number: 06/365,884
- Filed: 1982-04-06
- Granted: 1983-07-26
- Earliest claimed: 1980-04-17
- Assignees: Allied Eneabba Limited
- Inventors: Corbett J. Poynton
- Web page: https://patentgrep.com/patent/US4395384A

## CPC

- C01G 25/02: Oxides
- C01P 2006/10: Solid density
- C01P 2006/34: Melting temperatures
- C01P 2006/80: Compositional purity
- C01P 2006/90: Other properties not specified above
- C01G: COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F (metal hydrides {monoborane, diborane or addition complexes thereof} C01B6/00; salts of oxyacids of halogens C01B11/00; peroxides, salts or peroxyacids C01B15/00; thiosulfates, dithionites, polythionates C01B17/64; compounds containing selenium, or tellurium C01B19/00; binary compounds of nitrogen with metals C01B21/06; azides C01B21/08; {compounds containing nitrogen, other non-metals and metal C01B21/082}; metal amides C01B21/092; nitrites 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; compounds having molecular sieve properties but not having base-exchange properties C01B37/00; compounds having molecular sieve and base-exchange properties, e.g. crystalline zeolites, C01B39/00; cyanides C01C3/08; salts of cyanamide C01C3/16; thiocyanates C01C3/20)
- C01P: INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS

## Abstract

A process for the treating of zircon to remove a coating which contains iron from the surface of individual grains to make them move amenable to electrostatic and magnetic separation, wherein the method comprises coating the zircon grains with a strong basic reagent, calcining the coated grains and treating the calcined grains to remove the calcined impurities.

## Claims

### Claim 1

A process for the removal of surface impurities from zircon grains which comprises coating the zircon grains with a strong basic reagent, the coating being of an amount of 2 to 4% by weight of the zircon grains, calcining the coated grains at a temperature of at least 600.degree. C. for a retention time of more than about 10 minutes and no more than about 20 minutes, and removing the calcinated surface impurities from the calcined grains.

### Claim 2 (depends on 1)

A process as claimed in claim 1 wherein the basic reagent is sodium hydroxide or sodium carbonate.

### Claim 3 (depends on 2)

A process as claimed in claim 2 wherein the amount of sodium hydroxide is between 2% and 4% by weight of zircon.

### Claim 4 (depends on 1)

A process as claimed in claim 1, wherein the calcining is carried out at a temperature within the range 750.degree. C. to 800.degree. C.

### Claim 5 (depends on 1)

A process as claimed in claim 1 wherein sodium hydroxide is used as the basic reagent and wherein the calcined material is washed with water by conventional attritioning.

### Claim 6 (depends on 5)

A process as claimed in claim 5 wherein the washing water is heated to remove excess water and produce a solution of sodium hydroxide for re-use.

### Claim 7 (depends on 1)

A process as claimed in claim 1 wherein sodium carbonate is used as the basic reagent and the calcined material is washed with acid.

### Claim 8 (depends on 1)

A process as claimed in claim 1 wherein sodium hydroxide is used as the basic reagent and the calcining is carried out in the presence of carbon dioxide and the calcined material is washed with acid.

### Claim 9 (depends on 7)

A process as claimed in claim 7 wherein the amount of acid is between 3% and 5% by weight of zircon.

### Claim 10 (depends on 8)

A process according to claim 8 wherein the amount of acid is between 3% and 5% by weight of zircon.