ISO 4283:1993

All grades of fluorspar — Determination of carbonate content — Titrimetric method

The principle of the method specified is treatment of a test portion with hydrochloric acid solution, absorption of the evolved carbon dioxide in barium hydroxide solution, neutralization of excess alkali with hydrochloric acid solution, addition of an exactly measured excess of a standard volumetric hydrochloric acid solution to dissolve the precipitated barium carbonate and back-titration with a standard volumetric sodium hydroxide solution using methyl orange as indicator. The method is applicable to products having carbonate contents equal to or greater than 0,04 % (m/m).