Abstract
A study was conducted on manufacturing, from magnesium hydroxide (Mg(OH)2) suspension and ammonium bicarbonate (NH4HCO3) solution, magnesium carbonate (MgCO3·3H2O) which is raw material used for manufacturing basic magnesium carbonate as heat insulator pipes and boards. The following formula was used for this study:
Mg(OH)2+NH4HCO3+2H2O=MgCO3·3H2O+NH4OH
The method adopted consists in mixing 15% Mg(OH)2 suspension and 15% NH4HCO3 solution at the temperature of 40-50°C for 30 minutes. The shape of MgCO3·3H2O crystal prepared by the above mentioned method was of a needle type and similar to that prepared by the magnesium chloride (MgCl2) method. The former crystal, however, was smaller and thinner than the latter.
MgCl2+Na2CO3+3H2O=MgCO3·3H2O+2NaCl (MgCl2 method)
According to the X-ray diffraction and chemical analyses conducted, some Mg(OH)2 particles were found in the product obtained by this new method. The products of basic magnesium carbonate manufactured by these two methods were almost the same in physical and chemical properties, except for the results obtained from the differential thermal analysis.
