Process for producing unsintered cristobalite silica
AssigneesNitto Chemical Industry Co., Ltd., Mitsubishi Rayon Co., Ltd.
InventorsKoichi Orii, Iwao Ohshima, Naotake Watanabe
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Abstract
There is disclosed a process for producing unsintered cristobalite silica by heating an amorphous silica in the presence of an alkali component, which comprises heating an amorphous silica having a specific surface area (measured according to BET method) of 50 m.sup.2 /g or more at a temperature in the range of 1000.degree. to 1300.degree. C., in the presence of an alkali metal element in a concentration of 5 to 600 ppm to said silica to change it partially or completely into cristobalite and then heating at a temperature of exceeding 1300.degree. C. to eliminate alkali.
Claims9
A process for producing unsintered cristobalite silica by heating an amorphous silica in the presence of an alkali component, which comprises heating an amorphous silica having a specific surface area (measured according to BET method) of 50 m.sup.2 / g or more at a temperature in the range of 1000.degree. to 1300.degree. C. in the presence of an alkali metal component in a concentration of 5 to 600 ppm to said silica to change it partially or completely into cristobalite and then heating at a temperature exceeding 1300.degree. C to eliminate alkali.
Dependencies are inferred from the claim text.