粉煤灰微珠表面包覆机理研究

Mechanism of Surface Coating of Fly Ash Cenospheres

描述了微珠-氢氧化钙溶液体系中复合微珠的制备和表征方法.探讨了95℃恒温状态下氢氧化钙含量、微珠中活性组分随反应时间的变化规律.分析了体系温度和反应时间对包覆层生长过程的影响,结果表明:体系温度和反应时间是加速氢氧化钙对微珠产生水化作用的重要参数,两者之间具有协同效应;体系温度越高,所需反应时间越短,反之亦然.根据反应体系中氢氧化钙最强衍射峰强的变化规律,研究了微珠表面包覆层生长机制和包覆机理.结果表明:包覆层生长过程经历了诱导期、加速期、稳定期和颗粒快速生长期4个阶段.

Fabrication and characteristics of composite cenospheres are described in the fly ash cenosphere-calcium hydroxide solution system. The change law of calcium hydroxide ＆ active components excited from cenosphere with reaction time are analyzed under the 95 ℃ isothermal reaction condition. The effects of temperature and reaction time on growth of coating layer are studied. The results show that the temperature and time are important factors to speed up the hydration of cenosphere in calcium hydroxide solution. The higher the temperature is, the shorter the reaction time is, and vice versa because of their interaction. The coating layer growth and modification mechanism are researched according to the change of the strongest characteristic peak intensity of calcium hydroxide. The results show that the growing process of coating layer can be divided into following four steps： induction period, speedup period, stabilization period and particle quick growth period.