fertilizer grade magnesium sulfate heptahydratemagnesium sulphate,also named magnesium sulfate heptahydrate, epsom salts; bitter salts, when it is used in industry, it is MgSO4.7H2O.Magnesium sulphate is mainly used in industry, agriculture,food,feedstuff,medical and fertilizer AppearanceWhite small granularMain content99.5% minMgSO448.59% minMgO16.27% minMg9.81% minPH(5W/V%Sol)5-8Ferron(Fe)0.0015% maxChloride(CL)0.015%Heavy metal (Pb)0.0008 %maxArsenic(As)0.0002% maxInsoluble0.01%maxSize (mm)0.1-10.2-31-4