Synthesis via Precursor Method and Shape Evolution of Basic Magnesium Carbonate

Basic magnesium carbonate(4 MgCO3·Mg(OH)2·4 H2 O) with spherical-like structure was synthesized through precursors thermal decomposition. The precursor of magnesium carbonate trihydrates(MgCO3·3 H2 O) was synthesized by brine and ammonium bicarbonate, and the thermal decomposition conditions were investigated in detail. The obtained particulate was characterized using SEM, XRD and laser particle analyzer. The result showed that it was easy to obtain spherical-like 4 MgCO3·Mg(OH)2·4 H2 O by precursor thermal decomposition at 80~100 ℃ with thermal decomposition time 90 min, stirring time 15 min and the liquid initial concentration 0.1 mol/L, while rod-like 4 MgCO3·Mg(OH)2·4 H2 O with a surface of "house of card" structure was more likely to be obtained at low temperature(55 ℃), and rosette-like products were obtained at a little higher temperature(80 ℃) by direct synthesis.