... physicochemical property: white monoclinic crystal powder, with smell of SO2, the relative density is 1.49, easily ... SO2 in air. It usally contain different rate of Sodium Metabisulfite. Quality Standards: HG/T 3814-2006ItemIndexcontent ... industry, Leather industry, Chemosynthesis industry; and used in production of Pharmaceutical Intermediate , and used as developer, bleaching agency, preservative, ...