加压碳酸化法制备片状纳米碳酸钙及其表征

Preparation and Characterization of Flake-like Nano Calcium Carbonate by Pressurized Carbonation

以氢氧化钙和二氧化碳为反应原料,二水合柠檬酸三钠(Na3C6H5O7·2H2O)为晶型控制剂,乙醇为助表面活性剂,采用加压碳酸化法成功制备了片状碳酸钙。通过场发射扫描电镜(FESEM)、X射线衍射(XRD)、红外光谱(FTIR)、原子力显微镜(AFM)等手段对样品的形貌和结构进行了表征,并考察了柠檬酸钠添加量、反应温度、乙醇添加量、CO_(2)压力等对产品的影响。结果表明,在反应温度为100℃、柠檬酸钠添加量为8%、乙醇添加量为10 mL和CO_(2)压力为1.5 MPa的条件下,成功制备了厚度为7~8 nm、宽约为3.5μm、长约为25μm、长宽比约为7∶1的片状纳米碳酸钙,产品大小均一,形貌较为规整。片状碳酸钙的晶型为方解石型,比表面积约为27.11 m^(2)·g^(-1)。加压碳酸化增加了CO_(2)在溶液中的溶解度,在柠檬酸三钠的作用下定向生成片状纳米碳酸钙。

With calcium hydroxide and carbon dioxide as raw materials,trisodium citrate dihydrate as crystal control agents and ethanol as co-surfactant,flake-like calcium carbonate were successful prepared by pressurized carbonation.The morphology and structure of the samples were characterized by FESEM,XRD,FTIR,AFM,etc.And the influences of calcium carbonate morphology are investigated by changing the amount of adding trisodium citrate dehydrate and ethanol,the reaction temperature,the pressure of the CO_(2),etc.The results showed that under the conditions of reaction temperature of 100℃,sodium citrate content of 8%,ethanol content of 10 mL and CO_(2) pressure of 1.5 MPa,flake-like nano calcium carbonate with thickness of about 7—8 nm,width of about 3.5μm,length of about 25μm and length to width ratio of about 7∶1 was successfully prepared,and the products were of uniform sizes and relatively regular morphologies.The crystalline form of flake-like calcium carbonate was calcite,and the specific surface area was about 27.11 m^(2)·g^(-1).Pressurized carbonation increased the solubility of CO_(2) in solution,and under the action of trisodium citrate,flake-like nano calcium carbonate was directionally formed.