Used in the production of barium salts and as a precursor in the manufacture of heat treatment salts for hardening steel. Employed in the purification of brine solutions in caustic chlorine plants due to its ability to remove sulfate impurities. Also applied in the laboratory for qualitative analysis, particularly in testing for sulfate ions, forming a characteristic white precipitate. Historically used in the glass and ceramic industries to improve clarity and color, though this use has declined due to toxicity concerns. Limited use in the oil and gas industry for certain types of drilling fluids.