SINTERING OF FUSED SILICA TO PRODUCE SHAPED BODIES COMPRISING CRYSTALLINE SIO2

摘要

A method for preparing a formed body comprising fused silica simply and rapidly by sintering is provided, and a formed body which causes virtually no contamination of a melt in contact with the formed body even at high temperatures is provided. A method for preparing a formed body comprising the steps of: (a) providing fused silica in the form of essentially amorphous SiO2 grains; (b) adding water to the fused silica grains to produce a slip; (c) casting the slip into a mold which comprises a hollow body having a shape opposite to that of the formed body to be prepared; (d) drying the slip to obtain an intermediate body; (e) sintering the intermediate body at a sintering temperature at which at least a portion of the fused silica is transformed from an amorphous modification into a crystalline modification; and (f) cooling the sintered formed body to a temperature of 300 deg.C or less to form a microstructure containing crystalline SiO2. Further, the step of sintering the intermediate body is performed at a sintering temperature of 1180 °C or more.