Magnesium sulfate heptahydrate (molecular formula MgSO4 · 7H2O), also known as sulfurous, bitter salt, purgative salt and purgative salt, is white or colorless acicular or oblique columnar crystal, odorless, cool and slightly bitter, molecular weight: 246.47, specific gravity: 1.68, easily soluble in water, slightly soluble in ethanol and glycerin, and soluble in its own crystal water at 67.5 ℃. When decomposed by heat, 70 ℃ and 80 ℃ are crystal water without four molecules. At about 200 ℃, all crystal water is lost and becomes anhydrous. It is easy to be weathered into powder in the air (dry). When heated, the crystal water is gradually removed and becomes anhydrous magnesium sulfate. This product does not contain any toxic impurities. Magnesium sulfate heptahydrate is easier to weigh than anhydrous magnesium sulfate because it is not easy to dissolve, which is convenient for quantitative control in industry. Magnesium sulfate monohydrate white particles

It is mainly used in the manufacture of fertilizer, white granule leather making of magnesium sulfate monohydrate, printing and dyeing, catalyst, paper making, plastics, porcelain, pigment, match, explosive and fireproof materials. It can be used for printing and dyeing thin cotton cloth and silk, as the weighting agent of cotton silk and filler of kapok products; Used medicinally as cathartic salt.