Abstract: Disclosed is a method for producing a fluoroalkanesulfonic acid including (1) the step of reacting concentrated sulfuric acid and/or fuming sulfuric acid with a fluoroalkanesulfonate to cause an acid decomposition, thereby obtaining a reaction mixture containing the fluoroalkanesulfonic acid and a sulfur component; and (2) the step of adding an oxidizing agent to the reaction mixture obtained by the above step and then conducting a distillation, thereby obtaining the fluoroalkanesulfonic acid from the reaction mixture. It is possible by this method to efficiently reduce the sulfur component, thereby industrially advantageously obtaining fluoroalkanesulfonic acid of high purity.

Abstract: Disclosed is a method for producing a fluoroalkanesulfonic acid including (1) the step of reacting concentrated sulfuric acid and/or fuming sulfuric acid with a fluoroalkanesulfonate to cause an acid decomposition, thereby obtaining a reaction mixture containing the fluoroalkanesulfonic acid and a sulfur component; and (2) the step of adding an oxidizing agent to the reaction mixture obtained by the above step and then conducting a distillation, thereby obtaining the fluoroalkanesulfonic acid from the reaction mixture. It is possible by this method to efficiently reduce the sulfur component, thereby industrially advantageously obtaining fluoroalkanesulfonic acid of high purity.

Abstract: A process for removing a phosphorus component from fluorite containing such phosphorus component, which process comprises adding powder of the fluorite to an aqueous acid solution having an acid concentration of from 1.0 to 20 Wt% in an inorganic acid/phosphorus ratio of above 25:1 by mole to give a slurry, agitating the slurry at a temperature below 50.degree. C., and collecting the powder from the slurry. The mother liquor obtained after separation of the powder from the slurry may be recycled to the first step.