锆英石热分解的实验研究

EXPERIMENTAL STUDIES ON ZIRCON THERMAL DECOMPOSITION

在碳管炉内进行了锆英石热分解的实验研究．讨论了温度、颗粒和添加剂（MgO、CaO等）对锆英石热分解的影响低温区（≤1700℃）的锆英石分解是受化学反应速度控制，表现反应级数为零级，表观活化能为585．0kJ／mol，用动力学方程能较好地解析低温区的锆英石热分解反应，高温区（＞1700℃）主要是SiO（g）等气体通过反应层的扩散来控制，锆英石的热分解也受粒度的影响，颗粒越细，其分解率越大，加入MgO。

The experiment of zircon thermal decomposition is made in a carbon tube furnace.The results show that the factors such as temperature, particle size of zircon and additives thect the decomposition. In the low temperature zone (≤1700℃), the d ecomposition is controlled by chemical reaction.Its apparent reaction rate is zero degree, and apparent activation energy is 585.0 kJ/mol.In the high temperature zone(> 1700℃), the key limited step of decomposition is outward diffusion that mainly centralize in the process of SiO(g) penetrating through reacting layers.The particle size of zircon affects amount of dissociated zircon,the smaller,the better.The addition of MgO, CaO or Al2O3 is able to facilitate decomposition of zircon.