高分散轻质碳酸钙的制备工艺优化研究

The Research on Optimization of Preparation Technology of Highly Dispersed Light Calcium Carbonate

以某工厂的石灰乳作为原料,采用碳化法制备高分散轻质碳酸钙。在不进行搅拌的前提下,优化二氧化碳流速、碳化温度、分散剂和晶型控制剂的选择等工艺条件,来实现对高分散轻质碳酸钙的可控制备,最终得到形貌均匀、分散优良、粒径较小、品质稳定的轻质碳酸钙产品。结果表明,当试验条件中二氧化碳流速为2 L/min、恒温水浴温度为70℃、分散剂为六偏磷酸钠(2 g)、晶型控制剂为MgCl2时,反应得到的最佳样品的D50粒度为2.32μm,D90粒度为6.40μm。通过SEM分析得到最佳产品的表面形貌并对其形成机理进行讨论;XRD分析表明,表面改性剂分子已经吸附在碳酸钙表面并与其化学键配合。改性后的碳酸钙粒度均匀且分散性得到了极大优化。

In this paper,a high-dispersion light calcium carbonate is prepared by carbonization using lime milk of a factory as a raw material.Under the precondition of no stirring,the experiment optimizes the process conditions such as carbon dioxide flow rate,carbonization temperature,the selection of dispersant and crystallizer control agent to achieve the controllable preparation of highly dispersed light calcium carbonate.And finally,the light calcium carbonate products with uniform appearance,fine dispersion,small particle size and stable quality were obtained.The results show that when the carbon dioxide flow rate is 2 L/min,the temperature of the constant temperature water bath is 70℃,the dispersant agent is sodium hexametaphosphate(2 g),the crystal control agent is MgCl2,the optimum sample of the experimental reaction is obtained and have a D50 particle size of 2.32μm and a D90 particle size of 6.40μm.The surface morphology of the best product is obtained by SEM analysis and its formation mechanism is discussed.XRD analysis shows that the surface modifier molecules have been adsorbed on the surface of calcium carbonate and matched with its chemical bonds.The particle size of the modified calcium carbonate is uniform and the dispersion is greatly optimized.