... ; sulfuric acid, disodium salt; sodium sulfate; Speed-dry, sodium sulphate anhydrousITEMSTANDARDsodium sulphate (Na2SO4), %:98.0 MIN.water insolubles , %:0.05 MAX.Ca + Mg (as ... (Fe) , %:0.002 MAX.moisture , %:0.20 MAX.Whiteness, %:82 MIN. sodium sulphate