SiO_2在KCl-NaCl-NaF体系中的溶解度及溶解机理

Solubility and dissolving mechanism of SiO_2 in KCl-NaCl-NaF molten salt

用等温饱和法研究温度及熔盐组分对SiO2在KCl-NaCl-NaF体系中溶解度的影响。通过对熔盐急冷试样的X射线衍射分析和对该体系各物质间反应的热力学分析,确定了SiO2的溶解机理。结果表明:SiO2的溶解机理为6NaF(L)+3SiO2(S)=Na2SiF6(L)+2Na2SiO3(L);SiO2的溶解度随温度的升高、组元NaF摩尔分数的增加而增大,并且在KCl与NaCl摩尔比为1时,SiO2的溶解度与NaF摩尔分数呈线性关系。

The influence of temperature and component to solubility of SiO2 in KCl-NaCl-NaF molten salt was researched by isothermal saturation method. The dissolving mechanism of SiO2 was confirmed by X-ray diffraction to quench sample of molten salt and thermodynamic analysis to the system. The results show that dissolving mechanism of SiO2 is 6NaF（L）＋3SiO2（s）=Na2SiF6（L）＋2Na2SiO3（L）, the solubility of SiO2 increases with the increase of temperature and of NaF content and appears linearity relation to NaF content at x（KCI）：x（NaCI）=1.