Andalusite: a promising material for the top-quality refractory production

摘要

Mullitization of andalusite is considered. This phase transition is based on the mechanism of polymorphism (which holds the grain shape) and on the chemistry of solid-phase processes. Mullite is oriented along C-axis of generating andalusitecrystal. Single crystal of andalusite is transformed into mullite compound with capillary pores filled with glass-phase saturated with amorphous silica. Capillaries form the net of tightly bound tubular pores with 1 - μm cross-section that are orientedalong C-axis which is common both for mullite and parent andalusite. About 80% of the glass-phase is stored in the capillary pores of mullite. The results obtained are tested in reactions of andalusites of different grain composition with powder aluminaand are used in production of unshaped refractories having ultra-low cement content and cement-free masses with fine grained andalusite and alumina.