Kinetic features of breunnerite decarbonization

Resumo

The decarbonization of breunnerite from talc waste is analyzed by thermogravimetry. The temperatures of thermal effects are determined, and kinetic models for the process are proposed to describe the mechanism of breunnerite decomposition. The unit cell parameters of breunnerite (Mg_xFe_1–x)CO₃ and the product of its decomposition, iron–magnesium oxide (Mg,Fe)O, are calculated. The apparent activation energies E_a of the decomposition are calculated using the Ozawa–Flynn–Wall and Kissenger model-free methods and the Avrami–Erofeev one-step model. Depending on the chosen model, the values of E_a range within 180–185 kJ/mol. The conditions of breunnerite roasting for the subsequent use of the obtained material in metallurgical processes are substantiated.