magnesium carbonate is basic hydrated magnesium carbonate or normal hydrated magnesium carbonate. Due to the different crystallization conditions, the product can be divided into light and heavy, generally light. It is trihydrate at room temperature. The light weight is white fragile block or loose white powder. Odorless. Stable in air. When heated to 700 ℃, carbon dioxide is released to form magnesium oxide. It is almost insoluble in water, but causes slight alkaline reaction in water. Insoluble in ethanol, soluble in dilute acid and foaming
Magnesium carbonate Specification:
|
MgO |
40.0%-43.5% |
|
CaO |
0.6% Max |
|
Fe |
0.2% Max |
|
Moisture |
3.0 % Max |
|
Loss on burn |
56% Max |
|
Sulphate |
0.2% Max |
|
Chloride |
0.1%Max |
|
HCL-insoluble matter |
1% Max |
|
Mn |
0.005% Max |
|
Sieve residue |
0.05% Max |
synthetic method
1. Magnesia is obtained by mixing magnesite (MgCO3) with coke and roasting. After adding water to form sludge, CO2 is introduced to obtain magnesium bicarbonate, and after filtration, the filtrate is heated to obtain basic carbonate precipitation.
2. Dolomite (MgCO3 · CaCO3) is heated with low fire, only magnesium carbonate is decomposed and crushed. When it is reacted with water and carbon dioxide at 0.508-0.609 MPa, magnesium oxide is converted into magnesium bicarbonate and dissolved. At this time, calcium carbonate is left, which is obtained by filtration and heating.
3. Dissolve the same amount of crystalline magnesium sulfate and crystalline sodium carbonate in 10 times of water respectively, heat them to 60-80 ℃ and mix them thoroughly to produce CO2 gas and precipitate at the same time. The precipitate is filtered out, mixed with 70-80 ℃ hot water, and then filtered. The washing process was repeated and the precipitate was washed thoroughly and dried at 50-60 ℃
