Effect of System Pressure on the Surface Microstructure of Spherical Porous Basic Magnesium Carbonate

spherical porous basic magnesium carbonate (Mg 5 (CO 3 ) 4 (OH) 2 .4H 2 O) has been prepared by using ammonium bicarbonate and magnesium chloride hexahydrate as raw materials. A novel CO 2 bubble template was constructed to explain the formation of pore structure of porous Mg 5 (CO 3 ) 4 (OH) 2 .4H 2 O. System pressure was found to be important in controlling the final pore size of spherical porous Mg 5 (CO 3 ) 4 (OH) 2 .4H 2 O. By the investigation of the particles from pressure-dependent experiments, scanning electron microscopy observations, X-ray diffraction, and Fourier transform infrared spectra were used to follow the reactions and identify the products. The results show that the pore size of spherical porous Mg 5 (CO 3 ) 4 (OH) 2 .4H 2 O gradually decreased via increasing system pressure.