链状纳米碳酸钙的制备

Preparation of Chain-like Nanometer CaCO_3 Particles

用间歇鼓泡碳化法制备了链状纳米CaCO3,用pH计和电导仪对碳化反应跟踪检测 ,对其形成机理进行了分析 ,实现了对链状CaCO3的粒度控制。考察了碳化反应过程中pH值、电导率和反应物质量分数、反应温度、CO2 气体流等因素对产品粒径和形态的影响。结果表明 ,碳化反应过程中 pH值和电导率都有一个快速下降阶段。其中电导率有两个下降回复过程。Ca(OH) 2 质量分数、CO2 流量的增大、反应温度升高都会使反应速率和晶核生长速率变大。反应温度控制在 30℃左右 ,Ca(OH) 2 质量分数为 1 0 %左右 ,在一定范围内CO2

Chainlike nanometer calcium carbonate was prepared by intermittent carbonation method. The carbonization reaction was analyzed by using conductivity gauge and pH value. The mechanism of synthesis was discussed.The chain like calcium carbonate products with different grain size were synthesized. The influence of the operation conditions such as reactant concentration, reaction temperature, the flux of carbon dioxide, additives etc,on the grains size and shape was discussed. The experiments indicated that the additive and time to add it were the key factor of morphology of calcium carbonate in the carbonate process and the shapes of calcium carbonate particles. With this understanding, and CaCO 3 with average diameter of 40～50 nm and aspect ratio of 10 was prepared aftre the preparation condition were optimized.