April 2014
Chemical Industry & Chemical Engineering Quarterly;2014, Vol. 20 Issue 2, p215
Academic Journal
Apatite is a raw material mainly used in phosphate fertilizer, and partly used in yellow phosphorus, red phosphorus, and phosphoric acid in the industry. With the decrease of the high-grade phosphorite lump, the agglomeration process is necessary for the phosphorite concentrate after the beneficiation process. The decomposition behavior and the phase transformation are of vital importance for the agglomeration process of phosphorite. In this study, the thermal kinetic analysis method was used to study the kinetics of the decomposition of phosphorite concentrate. The phosphorite concentrate was heated at various heating rates, and the phases in the heated sample were examined by X-ray diffraction. It was found that the main phases in the phosphorite are fluorapatite Ca5(PO4)3F, quartz SiO2, and dolomite CaMg(CO3)2. The endothermic DSC peak corresponding to the mass loss caused by the decomposition of dolomite covers from 600-850 °C. The activation energy of the decomposition of dolomite, which increases with the increase in the extent of conversion, is about 71.6-123.6 kJ/mol. The mechanism equation for the decomposition of dolomite agrees with the Valensi Equation and G-B Equation.


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