摘要
本文采用碳化法,在改进了气体分布器的自制鼓泡搅拌釜中,以MgCl2和ZnSO4为晶型控制剂制备了不同形貌的碳酸钙。主要讨论了晶型控制剂、碳化温度、CO2流速等因素对碳酸钙形貌的影响,并在此基础上提出了各自的生长机理。产品用SEM、XRD进行形貌观察和晶型分析,结果显示当以MgCl2作为晶型控制剂时,需在高温、低CO2流速的条件下才能制备出结晶度好、文石相含量高的针状碳酸钙;而当采用ZnSO4作为晶型控制剂时,需在低温、高CO2流速条件下才能制备出单一方解石相的立方状纳米级碳酸钙。在最佳条件下制备的针状碳酸钙的粒径为0.5~2μm,长径比为10~20;制备的立方状碳酸钙的粒径为30~80nm。
Need-like and cubic calcium carbonate were synthesized in a stirred bubble tank equipped with a self-made gas distributor by carbonation process of Ca（OH）_2 slurry where MgCl_2 and ZnSO_4 were used as crystal controlling agents.Effects of the main operation conditions including crystal control agent,reaction temperature and flow rate of CO_2 on the particle size and morphology of precipitated calcium carbonate were investigated,and the crystal growth mechanisms were further discussed.The morphology and particle size of calcium carbonate were characterized by scanning electron microscopy（SEM）.The polymorphs were characterized by using X-ray diffractometry（XRD）.The results show that well crystallized needle-like CaCO_3 of high aragonite phase content and pure calcite cubic nano-CaCO_3 particulates are prepared with MgCl_2 and ZnSO_4 as crystal controlling agents,respectively.Under the optimal operation parameters,the needle-like CaCO_3 particulates are prepared with diameter of 0.5~2μm and aspect ratio of 10~20 while the cubic nano-CaCO_3 particulates are prepared with diameter of 30~80nm.
出处
《材料科学与工程学报》
CAS
CSCD
北大核心
2011年第2期227-232,共6页
Journal of Materials Science and Engineering
关键词
碳酸钙
碳化法
针状
立方状
生长机理
calcium carbonate
carbonation
needle-like
cubic
crystal growth mechanism
