Effect of mode of silica addition on the transformation of quartz into cristobalite

The effect of the different forms of active silica, namely, silica gel, silica glass, rice husk ash silica (RH-ash) and fine quartz on the transformation of quartz into cristobalite was followed at different temperatures ranging from 1350 to 1500°C. A mixture of 95% quartz and 5% of the different active forms of silica was studied. The transformation reaction was followed by DSC and by X-ray analysis. SEM studies were carried out to throw light on the texture of the powders and the bodies produced. Results showed that the different additives acted in various ways on the transformation process and size of the cristobalite formed.