Desilication kinetics of calcined boron mud in molten sodium hydroxide media
Zhi-qiang Ning , Qiu-shi Song , Yu-chun Zhai , Hong-wei Xie , Kai Yu
Journal of Central South University ›› 2016, Vol. 23 ›› Issue (9) : 2191 -2198.
Desilication kinetics of calcined boron mud (CBM) occurring in molten sodium hydroxide media was investigated. The effects of factors such as reaction temperature and NaOH-to-CBM mass ratio on silicon extraction efficiency were studied. The results show that silicon extraction efficiency increases with increasing the reaction time and NaOH-to-CBM mass ratio. There are two stages for the desilication process of the calcined boron mud. The overall desilication process follows the shrinking-core model, and the first and second stages of the process were determined to obey the shrinking-core model for surface chemical reaction and the diffusion through the product layer, respectively. The activation energies of the first and second stages were calculated to be 44.78 kJ/mol and 15.94 kJ/mol, respectively.
boron mud / sodium hydroxide / silicon dioxide / kinetics / desilication
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