ISO 5437:1992

Acid-grade and ceramic-grade fluorspar — Determination of barium sulfate content — Gravimetric method

The method is based on evaporation to dryness of a test portion in the presence of hydrofluoric acid and concentrated sulfuric acid, extraction of the soluble salts from the mixture, filtration, drying and weighing of the residual barium sulfate. Applies to products having barium sulfate contents equal to or greater than 0,1 % (m/m).