HWAHAK KONGHAK, Vol.11, No.1, 31-40, February, 1973
가스법에 의한 염기성 탄산마그네슘의 제조 (4. 염기성 탄산마그네슘의 생성)
Preparation of Basic Magnesium Carbonate by Gas Method(4. Formation Process of Basic Magnesium Carbonate)
The following results have been obtained through the studies on the preparation of basic magnesium carbonate by gas method.
The basic magnesium carbonate could be identified by means of the pH measurement, chemical analysis, refractive index, X-ray diffraction and microscopic studies.
The formation of basic magnesium carbonate from Mg（OH）2 suspension and CO2 depended on the concentration of Mg(OH)2 in the suspension and the flow rate of CO2 as well as on temperature.
The basic magnesium carbonate formation with 0.24 mole/1 of Mg（OH）2 suspension and CO2 flow rate of 33 ml/min at 70-90 ℃ did not give MgCO3·3H2O, but gave a compound with mole ratio of CO2/MgO of 0.75-0.84, which corresponds approximately to (3-5) MgCO3·Mg(OH)2·(3-5) H2O. The refractive index was about 1.531.
When Mg（HCO3）2 solution was heated, a metastable compound was formed initially, which then transformed into MgCO3·3H2O, and this in turn gave basic magnesium carbonate by decomposition (into CO2 and H2O).
In order to obtain the best quality basic salt, it is therefore important to assure that Mg（OH）2, neutral Mg-salt and amorphous compound do not coexists in the finished product.
The basic magnesium carbonate could be identified by means of the pH measurement, chemical analysis, refractive index, X-ray diffraction and microscopic studies.
The formation of basic magnesium carbonate from Mg（OH）2 suspension and CO2 depended on the concentration of Mg(OH)2 in the suspension and the flow rate of CO2 as well as on temperature.
The basic magnesium carbonate formation with 0.24 mole/1 of Mg（OH）2 suspension and CO2 flow rate of 33 ml/min at 70-90 ℃ did not give MgCO3·3H2O, but gave a compound with mole ratio of CO2/MgO of 0.75-0.84, which corresponds approximately to (3-5) MgCO3·Mg(OH)2·(3-5) H2O. The refractive index was about 1.531.
When Mg（HCO3）2 solution was heated, a metastable compound was formed initially, which then transformed into MgCO3·3H2O, and this in turn gave basic magnesium carbonate by decomposition (into CO2 and H2O).
In order to obtain the best quality basic salt, it is therefore important to assure that Mg（OH）2, neutral Mg-salt and amorphous compound do not coexists in the finished product.