微细针状碳酸钙的超重力法制备及表征

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

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～ 2 0 0nm、长径比为 12～ 2 0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 5 2 8℃ ,比重力场中合成的CaCO3 分解温度降低了 2 97℃。

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 distribution of both of them. In the experiment, reactants are Ca(OH) 2 and CO 2, and MgCl 2 is used as a morphology control additive. The properties of the product were characterized by means of TEM, electron diffraction, XRD and TG DTA. XRD analysis shows that the obtained ultra fine needle like calcium carbonate particles are crystal, with two phases of aragonite and calcite, and the aragonite accounts for about 73% in content in the final ultra fine needle like CaCO 3. TG DTA analysis shows that the obtained product decomposes at 528?℃, which is 297?℃ lower than that of the normal CaCO 3.