A process for refining inorganic salts of an inorganic acid which is displaceable by sulfuric acid, such as phosphate and carbonate minerals like apatite and dolomite. In the process, an aqueous reaction mixture is provided comprising the salt and an aqueous reaction medium, and sulfur dioxide and oxygen are introduced into the aqueous medium. The salt, sulfur dioxide and oxygen are reacted in the aqueous medium to release the inorganic acid and to convert the inorganic salt to the corresponding inorganic sulfate.
Iowa State University Research Foundation, Inc.
Nikolai, William L. Jr. and Wheelock, Thomas D., "Process for mineral refining" (1975). Iowa State University Patents. 307.