ANDALUSITE, AN UNDER-UTILIZED REFRACTORY RAW MATERIAL WITH UNDEVELOPED HIGH POTENTIAL

摘要

A review of the published information on andalusite industrial refractory service shows that an apparent comparative minimum amount of industrial in-depth research has been actually carried out on andalusite in the recent past. This summary report has been compiled from a current review of the literature. Highlights are as follows: Over the past 25 years, andalusite has gradually become an important raw material of choice to the refractories industry, particularly in Europe, with South Africa being the traditional refractory major supplier, offering chemical and physical properties superior to many other refractory raw materials. Andalusite has not only replaced other raw materials such as chamotte, English china clay, bauxite, and fused alumina in certain specific markets, but it has also found its own unique cost-saving niche applications. Andalusite boasts an international market of over 300,000 mt/yr and is used in many industrialized, steel and aluminum-producing countries of the world. High temperature industrial/technological innovation has made progressively greater demands on the durability of refractory materials. High-grade refractories capable of meeting these demands require highly resistant raw materials for their manufacture, and one such raw material is andalusite, a high alumina aluminosilicate. Andalusite has the chemical composition Al2O3, SiO2. Small percentages of iron oxide, titanium oxide, and other minor impurities are frequently present. Andalusite is a member of the sillimanite group of minerals. Each of the three members of this group has a similar chemical composition but differs in physical and refractory properties. The third member of the group is kyanite ("cyanite" in older literature).