碳化法制备超细碳酸钙反应中凝胶现象的研究

Effect of Gelation on Preparation of Ultrafine CaCO_3 Powders

为了研究制备超细碳酸钙过程中凝胶现象对反应过程及产物性能的影响,本文中以碳化法制备超细碳酸钙中的凝胶现象为例,研究了不同工艺参数(温度、石灰乳浓度、碳化气体流量、添加剂)对凝胶现象的影响,探讨了凝胶产生的微观原因,并提出了加入适当成核添加剂以避免凝胶产生的新方法。研究结果表明,避免凝胶出现或减轻凝胶现象的主要方法是在保持产品粒径达到要求的前提下控制反应温度在一定范围内,CO2的气体流量不能过大,石灰乳液浓度不能过高。选择适当的能产生微晶的添加剂来优化反应进程,能够与体系中的反应物作用产生微晶的物质,避免凝胶的发生。

In order to research the vffccts ofgelation on the reaction protess and properties of product during preparing superfine CaCO3 powder, the effects of different parameters such as temperature, Ca（OH）2 encentration,CO2 flow rate and additive on the gelation were researched,taking the carbonization process of superfine CaCO3 powder as an example. The reasons of the gelation were discussed on microcosmic level.The new method for avoiding gelation by addition of nucleation agent was suggested, The results show that controlling the temperature, Ca（OH）2 concentration and CO2 flow rate in a suitable range can avoid or weaken the gelation. The suitable micro-crystalline nucleation agent can optimize the reaction process and avoid the gelation through producing some micro-crystalline resultants.