Magnesium sulfate heptahydrate is a white crystalline solid with a wide range of applications. It is often used as fertilizer and feed in agriculture, and used for tanning, explosives, fertilizer, paper making, porcelain and so on in industry.
So do you know how to make magnesium sulfate heptahydrate? The following is to share with you three production methods of magnesium sulfate heptahydrate.
Method 1: add sulfuric acid in natural magnesium carbonate (magnesite), remove carbon dioxide, recrystallization, magnesium vanadium sulfide (Kieserite, MgSO4·H2O) dissolved in hot water recrystallization, prepared from sea water.
Method 2 (seawater brine method) : seawater brine is obtained from seawater brine. After evaporation by brine mixing method, high-temperature salt is produced, and its composition is MgSO4>. 30%, NaCI< 35%, MgCl2 is about 7%, KCl is about 0.5%.
Bitter brine can be leached in 200g/L MgCl2 solution at 48℃, with less NaCl and more MgSO4 dissolved. After separation, the liquid was cooled to 10℃ and then the coarse MgSO4·7H2O was precipitated, and the finished product was obtained by secondary recrystallization.
Method 3 (sulfuric acid method) : in the neutralization tank, the diamondback soil is slowly added to the water and mother liquor, and then the sulfuric acid is used to neutralize the color from the earth to red, and the pH is controlled to be 5 and the relative density is 1.37-1.38 (39, 40 ° Be).
The neutralization solution was filtered at 80 ° C, and then pH was adjusted to 4 with sulfuric acid. An appropriate amount of seed was added and cooled to crystallize at 30 ° C.
After separation, the finished product is dried at 50-55 ℃, and the mother liquor is returned to the neutralization tank.
Low concentration of sulfuric acid and magnesium oxide content of 65% of the bitter soil neutralization reaction, through filtration, precipitation, concentration, crystallization, centrifugal separation, drying, magnesium sulfate heptahydrate.