微细针状碳酸钙的超重力法制备及表征

采用超重力反应结晶法,在旋转填充床(RPB)反应器中,以Ca(OH)2/CO2为反应物系,MgCl2作为晶形控制剂,在较短时间(约1h)内合成出了平均短轴为80～200nm、长径比为12～20且短轴及长径比分布较窄的微细针状碳酸钙;利用TEM、电子衍射、XRD、TG-DTA等手段对产品进行了表征.XRD分析表明,所制备微细针状碳酸钙为结晶态,含有文石及方解石两种晶型,文石相含量为73%.TG-DTA分析显示,所制备的微细针状碳酸钙起始分解温度为528℃,比重力场中合成的CaCO3分解温度降低了297℃.

Synthesis of ultra-fine needle-like calcium carbonate particles by high-gravity technology and its characterization

Ultra-fine needle-like calcium carbonate particles were successfully synthesized by high-gravity reactive precipitation in a rotating packed bed (RPB) . The reaction only took about an hour. The average shaft diameter and aspect ratio of the resultant particles were 80～200 nm and 12～20 respectively , with a narrow dist ribution of both of them. In the experiment , reactant s are Ca (OH) 2 and CO2 , and MgCl₂ is used as a morphology-control additive. The properties of the product were characterized by means of TEM , elect ron diff raction , XRD and TG-DTA. XRD analysis shows that the obtained ultra-fine needle2like calcium carbonate particles are crystal ,with two phases of aragonite and calcite , and the aragonite account s for about 73 % in content in the final ultra-fine needle2like CaCO₃ . TG2DTA analysis shows that the obtained product decomposes at 528 ℃, which is297 ℃lower than that of the normal CaCO₃