Iron oxide is an important impurity in micronized silica powder which has an adverse effect on quality of the product. Not only it causes different colours in the glass but it brings out some difficulties in glass production line as well. In this article, silica used by Takestan Glass Company, a major producer of glass in the country is upgraded by acid leach and magnetic separation techniques. A sample feed with 0.082% iron oxide was used in mineralogical studies. This sample was then concentrated under different conditions. Variables such as percentages of solid content in the pulp, acid leach conditioning time, temperature, type of acid used and its dosage, and magnetic field intensity were optimized. At last, the combination of acid leach and magnetic separation methods was studied and results showed that a silica upgrade with 0.018% iron oxide can be achieved.
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