Abstract
The method of thermal effect of reactions for Eact calculation for the processes of chromite ore and clay interaction in solid phase was used in this research for obtaining kinetic data. These processes take place during hardening roasting of chromite ore pellets in derivatograph Q-1500. The samples of chromite ore, clay from Sazdinskoe deposit (Aktyubinsk region, Kazakhstan) and pellets were taken for examination of phase transformations during hardening roasting. In the area of high temperatures, exothermic peaks with temperature maximum values 1340 and 1430 °С are clearly observed on the differential and thermal curve of chromite ore; these maximal values are caused by recrystallization of chromium spinellid grains. Introduction of clay changes the features of diffusion processes in chromite ore. Observed lowering of apparent activation energy for each peak is separately connected with decrease of diffusion retarding processes. When conducting an experiment in argon neutral atmosphere, distinct peaks characterizing diffusion processes and reconstruction of chromium spinellid lattice are not observed. In this case, the value of apparent activation energy decreases seriously in comparison with activation energy of diffusion processes for the mix of chromite ore and clay in oxidizing atmosphere. Respectively, hardening processes during heat treatment of pellets, which are accompanied by diffusion of clay oxides in chromium spinellid lattice, will pass with rather high speed and will reach high degree of completeness at the roasting temperature of pellets (1200–1300 °С).