中文摘要：

利用低品位的菱镁矿,通过水化碳酸化得到重镁水,然后在50℃将重镁水热解制得碳酸镁,研究了热解条件对热解产物碳酸镁晶体形貌的影响。结果表明：热解产物为MgCO3·3H2O。当添加剂为磷酸二氢钾时,制备出花瓣状的碳酸镁;当添加剂为碳酸铵时,制备出球状的碳酸镁;当添加剂为可溶性镁盐时,制备出碳酸镁晶须。随着搅拌强度增大,产物的长径比先增大后减小。当添加可溶性镁盐,热解温度为50℃,搅拌强度为200r/m时,可获得长度为10～40μm,长径比为10～20的碳酸镁晶须。

英文摘要：

Magnesium carbonate crystal was obtained by thermal decomposition of Mg（HCO3）2 solution at 50 ℃.The solution was prepared by hydration and carbonation treatment of light burnt magnesia derived from magnesite.The influence of thermal decomposition conditions on the morphology of magnesium carbonate crystal was investigated.The results show that thermal decomposition products are MgCO3·3H2O.Petal shaped magnesium carbonate crystal was prepared when potassium dihydrogen phosphate was added,and a spherical magnesium carbonate crystal was obtained when ammonium carbonate was added.Magnesium carbonate whiskers were successfully prepared when soluble magnesium salt was added.The length-to-diameter ratio of the whisker first increased and then decreased with the increasing of stirring intensity.Magnesium carbonate whiskers with a length of 15 μm and a length-to-diameter ratio of 10-20 were obtained by the addition of soluble magnesium salt when the thermal decomposition temperature was 50 ℃ wi th a stirring intensity of 200 r/m.