Specifications: Content 99.6%MIN SO42- 0.10%MAX Residue on ignition 0.10%MAX Heavy metal(Pb) 0.002%MAX Fe 0.002%MAX Chloride(Cl) 0.005%MAX Uses:Pharmaceutical industry,precipitating agent of rare earth elements,bleaching,metal and marble polish,cleanser removing stains,tanning industry,printing and dyeing catalytic agent , anti-shrinkage finishing of paper ,manufacturing oxalates.