The alumino silicates gained importance in the ceramic field not only as raw material for ceramic bodies but also as new materials often found in the fired wares, were they occur in the form of acicular crystals. They are usually felted together in a state of disorder and occur preferentially as local agglomerations. They were first observed in thin sections of porcelain, later in refractory and in stone ware.
There is lot of research studies which revealed that these substances are formed by solidification from melts. Refractory materials made from pure mullite should melt at 1913oC. Refractory materials made from silliminite melt at 1880oC, whereas pure Kaolin refectories melt at 1718oC. The melting point almost matches with determined figures after experimentation.
To be contd…..
