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Synthesis and Characterization of Ultra-fine Calcium Carbonate Whiskers in High-Gravity
Zhu Wancheng1, Chen Jianfeng*2, Wang Yuhong2
1.Chemical Engineering Department,Qufu Normal University,Qufu 273165;2.Research Center of the Ministry of Education for High Gravity Engineering and Technology,Beijing University of Chemical Technology,Beijing 100029
Abstract:
Ultra-fine whiskers of calcium carbonate were successfully synthesized by reactive precipitation in highgravity field generated by the rotating packed bed(RPB). In the experiment Ca(OH)2 and CO2 were as reactants and H3PO4 was used as the morphology-control additive. Synthesizing the same amount of CaCO3 whiskers,the needed carbonation time in the high-gravity field is 1/36-1/18 of that by the traditional technology reported in the literature. The ultra-fine CaCO3 whiskers can be synthesized and well-controlled under the following conditions:the volumetric flow rate of gas 100-300 L/h and that of liquid 600-1000 L/h,rotating speed of RPB 600-1200 r/min,reaction temperature between 40-80℃ and concentration of H3PO4 5.0%-30%. The calcium carbonate whiskers have the mean shaft diameter of 80-250 nm and the average aspect ratio of 10-25 with the narrow distribution of both the mean shaft diameter and the aspect ratio. The properties of the product are characterized by means of TEM,electron diffraction,XRD,TG-DTA and elementary analysis. Electron diffraction analysis shows that the synthesized calcium carbonate whiskers have crystalline structure,while XRD analysis indicates that aragonite structure accounts for 97.77% in content of the final CaCO3 whisker product. And TG-DTA analysis shows that the obtained product decomposes at 423℃,which is 402℃ lower than that of the CaCO3 obtained in the normal gravity.
Key words:  Calcium carbonate,Whisker,Ultra-fine particles,High-gravity,Synthesis,Characterization
FundProject:
超重力环境中合成微细晶须碳酸钙及其表征
朱万诚1, 陈建峰*2, 王玉红2
1.曲阜师范大学化工系,曲阜 273165;2.北京化工大学教育部超重力工程研究中心,北京 100029
摘要:
在利用旋转产生的模拟超重力环境中,以Ca(OH)2-CO2为反应物系,H3PO4作为晶形控制剂,控制气体流量100~300 L/h,液体流量600~1000 L/h,旋转床转速600~1200 r/min,碳化反应温度为40~80℃,H3PO4相对于Ca(OH)2完全反应所生成CaCO3质量分数为5%~30%,采用反应结晶法制备出了平均短轴为80~250 nm、长径比为10~25的微细晶须碳酸钙. 制备等量的晶须碳酸钙,超重力环境中所需碳化时间约为文献值的1/36~1/18. 同时,利用TEM、XRD、TG-DTA及元素分析等手段对产品粒子进行了表征. 结果表明,所合成微细晶须碳酸钙为结晶态,文石型含量达到97.77%,初始分解温度较常重力场中下降了402℃.
关键词:  碳酸钙  晶须  微细  超重力  合成  表征
DOI:10.1088/1674-0068/17/2/175-178
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