... used in fertilizer Magnesium sulphate,also named magnesium sulfate heptahydrate, epsom salts; bitter salts, when it is used in industry, it is MgSO4 ... , papermaking, metallurgy, electronics, or used as fertilizer, feedstuff additives.99% Magnesium sulfate heptahydrate fertilizer quality index: AppearanceWhite small granularMain content99% minMgSO448 ...