基于补偿效应下CaSO_4产物层离子扩散的研究

The study of ion diffusion in CaSO_4 product layer based on compensation effect

石灰石脱硫反应中,高温热激活使得晶体产生大量的缺陷,局部电中性失去平衡,产物层内部Ca2+向外运动形成固态离子扩散。以直接脱硫实验为基础,利用电导率补偿效应找到了CaSO4产物层的特征温度和特征电导率,通过曲线拟合得到了产物层扩散激活能,最终计算获得了产物层离子扩散系数与温度之间的关系,结果表明:产物层离子扩散系数与温度成指数关系,温度越高,离子扩散系数越大,钙离子越活跃。较大迁移率使得更多的Ca2+跃迁至产物层表面与气体分子发生反应,有利于脱硫反应的进行,但考虑到高温石灰石会发生烧结,因此合理地选择脱硫温度是改善硫化反应的根本途径。

Thermal activation may lead to large amount of crystal defects,the local electrical neutrality was smashed and solid-state ion diffusion was formed for the sake of the movement of calcium in product layer at high temperatures.Based on the direct desulphurization experiment,this article is aimed to obtain the relationship between ion diffusion coefficient and temperature when characteristic temperature,characteristic conductivity and diffusion activation energy of CaSO4 product layer were calculated with the help of conductivity compensation effect and curve fitting.The results show that ion diffusion coefficient and temperature are exponential relationship,in addition,the higher the temperature,the bigger the ion diffusion coefficient,the more activate of calcium ions.The greater mobility,which is conducive to desulphurization,may lead large transition of calcium ions to the surface of product layer to react with gas molecules,however,limestone in high temperature will be sintered,so choosing reasonable desulphurization temperature is an appropriate way to improve the desulphurization reaction.