摘要 |
14 A method for working up fluorine-containing residues with recovery of aluminum fluoride according to which a mixture of finely particulate fluorine- and carbon-containing residues and SiO2 and SiO2-containing materials is heated in the presence of gaseous chlorine to temperatures between 400.degree. and 900.degree.C with about 98% of the fluoride content of the mixture being converted to gaseous silicon tetrafluoride, and, thereafter, the gaseous silicon tetrafluoride is converted either directly or after a transformation to hydrofluosilicic acid into aluminum fluoride by reaction with aluminum hydroxides or aluminum oxides. (AZ.app.1)
|