【摘要】 通过试验研究筛选出MgCl2与H3PO4两种在旋转填充床(RPB)中促使微细晶须碳酸钙合成的晶形控制剂,单因素试验探明了各晶形控制剂条件下合成微细晶须碳酸钙的较佳工艺条件,正交试验研究了各因素对粒子长径比影响的显著性.研究表明:与常重力场中合成晶须碳酸钙的方法相比,RPB产生的超重力场中合成晶须碳酸钙反应温度降低约20℃、合成等物质的量晶须碳酸钙所需时间约为其他方法的1/36-1/18、粒子短轴直径达到80-250nm微细程度;使用MgCl2时只有反应温度对粒子长径比有显著影响,而使用H3PO4时反应温度、RPB转速和气体体积流量对产品粒子长径比均有显著影响.更多还原

【Abstract】 A novel synthetic method for the ultra-fine CaCO3 whiskers was investigated in this paper. MgCl2 and H3PO4 were both determined to be effective morphology-control additives for the formation of ultra-fine whisker-like CaCO3 in the rotating packed bed reactor (RPBR) by experimental study. The optimal synthetic conditions for the ultra-fine whiskers of CaCO3 in the presence of two additives respectively were presented by the single-factor experiment. In contrast with other synthetic methods for CaCO3 whiskers carried out in normal gravity field, synthesis of calcium carbonate whiskers under high-gravity environment generated in the RPBR has shown substantial advantages. First of all, the carbonation temperature by this new method is approx 60 ℃ , which means 20 ℃ lower than other methods. Additionally, synthesizing the same moles of whiskers of CaCO3 the time needed is merely 1/36 - 1/18 of that reported by other methods, which implies a great deal of funds can be saved. Most importantly, the mean shaft diameter of the obtained whiskers is 80-250 nm instead of 0.5-3.0 μm demonstrated in other literature, which predicts the great potential use of the ultra-fine CaCO3 whiskers. The results of the orthogonal experiment show that when MgCl2is as the additive the temperature has prominent influence on the aspect ratio of the product particles, whereas H3PO4is as the additive, the temperature, volumetric flow rate of gas to liquid and the rotating speed of RPBR have remarkable impact on the aspect ratio of the whiskers of CaCO3.更多还原