PRODUCTION OF RUTILE-PRIDELITE-POTASSIUM HEXATITANATE COMPOSITE FIBER

PURPOSE:To manufacture the titled fiber having high heat resistance, heat insulation, chemical resistance, and reinforcing property, by melting the mixture of natural rutile snad, etc. with K2O, forming a fibrous material made of the same crystal as potassium dititanate, extracting K2O, and heating at a high temperature. CONSTITUTION:Natural rutile sand or anatase sand of formula (Ti,M)O2 (M is included impurity metal) is mixed with potassium oxide, a potassium compound forming potassium oxide with heat, or their mixture, at a ratio to form a mixture of formula K2O.n(Ti.M)O2 (n is 1.5-2.5), and the mixture is heated and melted. A fibrous material composed of crystal having the same lamellar structure as the structure of potassium dititanate (K2O.2TiO2) is formed from the melting mixture. After extracting a part of the K2O component from the fibrous material, the material is heat-treated at >=800 deg.C to obtain the objective composite fiber.