Kemija u Industriji (Oct 2010)
Enriching of Magnesite Ore Containing Dolomite
Abstract
Minor mineral phases containing calcium and silica in magnesite ore are the main cause of detrimental properties of magnesia refractory materials prepared thereof. All stages of the production process aim to remove such unwanted mineral phases. While the removal of silica minerals is well documented, it is not so for the calcium containing minerals, especially when it is not possible to do so by mechanical separation processes only. In this work, the influence of duration and temperature of heat treatment and subsequent hydration of magnesia has been studied. The final product obtained is a light component from the settling separation utilizing dense water suspension of ferrosilica. The optimal process conditions were: 4 to 6 h soaking at temperature between 600 and 700 °C with subsequent hydration of partially calcined product by immersion in water and settling separation at heavy fluid density ρ= 2.20 g cm–3. Furthermore, a positive influence of prolonged heat treatment on product quality as well as the optimal density of ferrosilica suspension has been obtained.
