碳酸钙超细粒子的制备

本文用不同的方法合成了由微米级到纳米级粒径不等的方解石型和文石型碳酸钙超细粒子,并对其各种的物理性质和结构进行了测定和表征。结果表明：随着粒径的减少,方解石微晶的完整性逐渐趋于破坏,结晶程度逐渐降低,而文石的软团聚性却逐渐趋于增强;并且粒径越小,碳酸钙超细粒子分解温度越低,活性越强。另外,本文还对方解石型和文石型碳酸钙超细粒子的形成机理和粒径控制进行了探讨,着重研究了温度、干燥方法和搅拌速率对超细粒子粒径的影响。并从结晶热力学的角度,分析了通常情况下制备文石型碳酸钙超细粒子的可行性。

Preparation of Ultra- fine Calcium Carbonate

In this paper, we have synthesized the ultra-fine calcium carbonate, namely calcite and vaterite, whose average diameters transfer from micron-size to manometer-size. And we have also investigated their crystal structures as whll as their physical properties. The result of determination proves that crystalline perfection of calcite is gradually ruined of their crystalline grade decline and soft reunite of vaterite arises with the change of the average diameters and that the smaller the diameters are, the lower the temperatures of decomposition are, in other words, the more active the ultra-particles are. In addition, the synthesis mechanism and the control of average diameter have been discussed. The important focus is placed on the research of the influence of temperature, the methods of dryness and the velocity of stir on the diameter. We have also discussed the feasibility to synthesis ultra-vaterite under usual condition from crystallite dynamics.