# US 7,744,847 B2 · Upgrading of zircon

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- Number: US 7,744,847 B2
- Document ID: US7744847B2
- Status: Granted
- Kind: B2
- Application number: 11/579,752
- Filed: 2005-05-24
- Published: 2007-12-20
- Granted: 2010-06-29
- Earliest claimed: 2004-05-27
- Assignees: The South African Nuclear Energy Corporation Limited
- Inventors: Ettienne Snyders
- Web page: https://patentgrep.com/patent/US7744847B2

## CPC

- C22B 1/02: Roasting processes (C22B1/16 takes precedence)
- C22B 1/00: Preliminary treatment of ores or scrap
- C22B 34/14: Obtaining zirconium or hafnium {(treatment or purification of solutions by liquid-liquid extraction, by ion exchange or by adsorption C22B3/00, C01G25/003, C01G27/003)}
- C22B 1/06: Sulfating roasting
- C22B 1/08: Chloridising roasting
- C22B: PRODUCTION AND REFINING OF METALS (electrolytic C25); PRETREATMENT OF RAW MATERIALS

## Abstract

A process for upgrading an inferior grade of zircon to a superior grade thereof includes mixing the inferior grade of zircon, in comminuted form, with at least one mineralizer, to obtain a zircon/mineralizer mixture, which is a calcined product. The calcined product is washed, and thereafter, in a comminution step, the washed calcined product is comminuted to obtain a superior grade of zircon, which is suitable for use as a glaze opacifier.

## Claims

### Claim 1

A dry process for upgrading an inferior grade of zircon to a superior grade thereof which is suitable for use as a glaze opacifier, which process includes
mixing a comminuted inferior grade of zircon with NaF and/or (NH4)2SO4 as a mineralizer, to obtain a comminuted zircon/mineralizer mixture in the form of a homogeneous blend;
calcining the comminuted zircon/mineralizer mixture, to produce a calcined product;
washing the calcined product; and
in a comminution step, comminuting the washed calcined product, to obtain a superior grade of zircon which is suitable for use as a glaze opacifier.

### Claim 2 (depends on 1)

A process according to claim 1 which includes, in a first comminution step, comminuting the inferior grade of zircon, with the comminution step in which the washed calcined product is comminuted thus constituting a second comminution step.

### Claim 3 (depends on 2)

A process according to claim 2 wherein, in the first comminution step, the inferior grade of zircon is comminuted sufficiently finely so that all zircon particles are 74 microns or smaller.

### Claim 4 (depends on 2)

A process according to claim 2, wherein the washing of the calcined product is by means of water.

### Claim 5 (depends on 2)

A process according to claim 2 wherein, in the second comminution step, the washed calcined product is comminuted down to a particle size smaller than 2.1 microns.

### Claim 6 (depends on 2)

A process according to claim 2, wherein wet milling is employed in the second comminution step, with the process including drying the superior grade zircon that is obtained from the second comminution step.

### Claim 7 (depends on 1)

A process according to claim 1, wherein the calcination temperature is from 600° C. to 900° C.