ISO 3703:1993

The principle of the method is treatment of a test portion with a mixture of dilute hydrochloric acid and an organic solvent, removal of the insoluble fluorspar by filtration under vacuum, separation of the organic phase containing the flotation agent, evaporation of the solvent and weighing of the residue. Applies to materials which have been subjected to flotation process and which have flotation agent contents equal to or greater than 0,002 % (m/m) of the dried material.