Basic properties of magnesium sulfate heptahydrate

The basic properties of magnesium sulfate heptahydrate:

     Heptahydrate sulfuric acid is an orthorhombic system, which is a tetragonal granular or rhomboid crystal, colorless and transparent, and the aggregate is white, rose or green glass.

     The sulfuric acid heptahydrate has a fibrous shape, a needle shape, a granular shape or a powder. Odorless, cool, bitter and salty, relative density 1.67 ~ 1.71. Soluble in water, slowly soluble in glycerin, slightly soluble in ethanol, neutral in aqueous solution, stable in humid air below 48.1 °C, easy to weather in warm dry air, above 18.1 °C, lose 1 crystal water It becomes magnesium sulfate hexahydrate, dissolves in its own crystal water at 67.5 ° C, and simultaneously precipitates magnesium sulfate monohydrate. At 70-80 ° C, it loses 4 crystal water, and loses 5 crystal water at 100 ° C at 150 ° C. When it loses 6 crystal waters, it loses all crystal water at 200 ° C and becomes powdery anhydrous magnesium sulfate. The dehydrated material is placed in humid air to reabsorb moisture.

Hexahydrate sulfuric acid can crystallize hydrated crystals with 1, 2, 3, 4, 5, 6, and 12 waters respectively in a saturated solution of magnesium sulfate, and precipitate 12 water in a saturated aqueous solution of -3.9 to 1.8 ° C. Magnesium sulfate, magnesium sulfate heptahydrate was precipitated in a saturated aqueous solution of -1.8 to 48.18 ° C, and magnesium sulfate hexahydrate was precipitated in a saturated aqueous solution of 48.1 to 67.5 ° C. When the temperature was higher than 67.5 ° C, magnesium sulfate monohydrate was precipitated, and magnesium sulfate hexahydrate was Heterogeneous melting occurs between 87 and 92 ° C, and produces pentahydrate or magnesium sulfate tetrahydrate. Magnesium sulfate tetrahydrate is converted into magnesium sulfate trihydrate at 106 ° C. Magnesium sulfate trihydrate is converted to magnesium sulfate dihydrate at 122-124 ° C. The magnesium sulfate dihydrate is converted to stable magnesium sulfate monohydrate at 161 to 169 °C.