magnesium sulphateheptahydrate, Purity:99.5%, Appearance:white crystal Specification:MgSO4.7H2O:99.5% minMgSO4 48.59% minMgO 16.27% minMg 9.81% minPH(5W/V%Sol) 5-8Ferron(Fe) 0.002% maxChloride(CL) 0.002%Heavy metal (Pb) 0.001 %maxArsenic(As) 0.0002% maxInsoluble 0.01%max Use: --Mainly used in fertilizer, tanning, pringting and dyeing,activator,papermaking,plastic,porcelain,pigment matchmaking , ...