Characteristic of thermal decomposition kinetics of main gold-bearing sulfides pyrite

Thermal decomposition kinetics of main gold-bearing sulfides pyrite was investigated by TG-DSC thermal analysis at different heating rates. The microstructures of pyrite before and after decomposition were analyzed by SEM. The results show that the thermal decomposition temperature of pyrite is between 400-800 ℃. The mass loss rate is approximately 26%. The TG curves move in the direction of high temperature with increasing the heating rate. This means that the same conversion can be gotten at higher temperature. The temperature range of the maximum pyrite thermal decomposition reaction rate of pyrite is between 600-700 ℃. The apparent activation energy E and pre-exponential factor A were calculated by Kissinger and Ozawa-Doyle methods, and the values are 259.23 kJ/mol and 1×1014.67, respectively. According to Coats-Redfern equation, linear regressions were carried out by common mechanism functions of thermal decomposition. It is defined that the thermal decomposition process of pyrite conforms to the Mample principle by Malek method, and the corresponding mechanism is the random nucleus and the consequent growth. The differential equation of thermal decomposition reaction was deduced as well. ©, 2015, Central South University of Technology. All right reserved.