铝杂质强化固相碳热还原氟磷灰石过程分析

Two reaction systems of carbonthermal reduction of fluorapatite were investigated in the tube furnace with protecting nitrogen,one of which contained 5%Al₂O₃,and the other didn’t contain any Al₂O₃.The results showed that the conversion fraction and the conversion rate of fluorapatite with 5%Al₂O₃are both higher.The analysis of XRD for the compositions of solid state products is consistent with the analysis of thermodynamics.The products of Al₂SiO₅,AlPO₄and CaAl₂Si₂O₈in 5%Al₂O₃reaction system cause the amount of liquid phase the increase of and then enhance the carbonthermal reduction.The solid state carbothermal reduction reaction of fluorapatite in the present of SiO₂and Al₂O₃belongs to gas-liquid-solid reaction and the reaction process meets the kinetic equation which was derived from the theory of layer growth based on reaction-diffusion.And more, the enhanced effect of adding Al₂O₃is more prominent at relative lower temperature or at the initial reaction stage especially.