Do You Know How To Extract Magnesium Sulfate Crystal Heptahydrate
Magnesium sulfate heptahydrate crystallization extraction method 1: adding sulfuric acid to natural magnesium carbonate (magnesite), removing carbon dioxide, recrystallizing, dissolving magnesium sulfate vanadium (kieserite, MgSO4 · H2O) in hot water, recrystallizing, and preparing from sea water.
Magnesium sulfate heptahydrate crystallization extraction method 2 (seawater salt bittern method): the bittern is obtained by seawater salt drying and evaporated by mixing brine method to produce high-temperature salt, whose composition is MgSO4 > 30%, NaCI < 35%, MgCl2 about 7%, KCl about 0.5%.
Bittern can be dissolved in 200 g / L MgCl2 solution at 48 ℃, less in NaCl and more in MgSO4. After separation, MgSO4 · 7H2O was precipitated after the soaking solution was cooled to 10 ℃, and the product was obtained by secondary recrystallization.
Magnesium sulfate heptahydrate crystallization extraction method 3 (sulfuric acid method): in the neutralization tank, first slowly add the magnesite into water and mother liquor, and then neutralize with sulfuric acid, until the color changes from earth color to red, control pH = 5, relative density 1.37-1.38 (39-40) ° B é)。 Filter the neutralizing solution at 80 ℃, adjust the pH value to 4 with sulfuric acid, add appropriate amount of seed, and cool to 30 ℃. After separation, the product is dried at 50 ~ 55 ℃, and the mother liquor is returned to the neutralization tank.
Magnesium sulfate heptahydrate can also be prepared by neutralization reaction of low concentration sulfuric acid with bitter earth containing 65% magnesium oxide, filtration, precipitation, concentration, crystallization, centrifugal separation and drying.
The chemical equation of crystallization of magnesium sulfate heptahydrate: MgO + H2SO4 + 6H2O → MgSO4 · 7H2O
