不同粒度纳米碳酸钙的可控制备

不同粒度的纳米碳酸钙具有不同的特性和应用范围,目前不同粒度纳米碳酸钙的可控制备方法还未见报道。以氯化钙、碳酸铵为原料,以乙醇、柠檬酸和焦磷酸钠为分散剂,采用复分解法研究了不同制备条件对纳米碳酸钙粒径的影响规律,在此基础上制备出平均粒径为17~71 nm的碳酸钙,并对其进行了表征。实验结果表明,所制备的纳米碳酸钙均为球霰石型,纯度很高,而且形貌近似球形。制备条件对纳米碳酸钙的粒径有显著的影响：随着反应温度升高,纳米碳酸钙的粒径减小;随着氯化钙滴加时间的增加,纳米碳酸钙的粒径增大;随着反应物浓度的提高,纳米碳酸钙的粒径先减小后增大;当分散剂为柠檬酸和焦磷酸钠的混合溶液时所得纳米碳酸钙的粒径最小,当分散剂为乙醇和焦磷酸钠的混合溶液时所得纳米碳酸钙的粒径最大。利用这些影响规律通过控制制备条件可以实现所需粒径纳米碳酸钙的可控制备。

Controllable preparation of nano-calcium carbonate with different particle sizes

Nano-CaCO₃ with different particle sizes have different characteristics and application scopes.So far the method of controllable preparation for nano-CaCO₃ with required particle sizes has not been reported.The effects of different experimental conditions on the particle size were studied by double decomposition method with calcium chloride and ammonium carbonate as raw materials,and with ethanol,citric acid and sodium pyrophosphate as disperants.Based on the research results,nano-CaCO₃ with the average size range at 17~71 nm were synthesized and characterized.The experimental results showed that,the samples prepared were vaterite structure with high purity,and the shapes were approximately spherical.The preparation conditions and disperants had significant influences on the particle size of nano-CaCO₃.As the reaction temperature increased the diameter decreased;the diameter increased with the increasing of the dropping time;with the concentration of the reactant increased,the particle size decreased first and then increasd; when the disperant additive was a mixed solution of citric acid and sodium pyrophosphate,the particle size was the smallest;when the disperant was a mixed solution of ethanol and sodium pyrophosphate,the particle size was the largest.Utilizing these influence rules,the controllable preparation of nano-CaCO₃ with the required particle sizes can be attained by controlling the experimental conditions.