The effects of hydration activity of calcined dolomite (HCD) on the silicothermic reduction process

• Hydration activity of calcined dolomite affects the silicothermic reduction process.
• The influence mechanism was studied by experiments.
• A numerical model was first developed and verified by a series of experiments.
• The hydration activity of calcined dolomite should not be lower than 25%.

In this paper, the effects of hydration activity of calcined dolomite (HCD) on silicothermic reduction process were studied. A series of experiments were carried out on a single briquette to investigate the impact of different HCD on the chemical reaction kinetics of the silicothermic reduction process. This study was the first to experimentally show that HCD plays an important role in the intrinsic chemical reaction rate of the silicothermic reduction process, but has no impact on the final reduction rate. The chemical kinetic data of the silicothermic reduction process with different HCD was obtained at a temperature range from 1323–1473 K. And then, a numerical model considering both heat transfer by radiation and heat conduction and chemical kinetics was developed according to the experimental data, and was used to simulate the phenomenon of heat transfer occurring during the silicothermic reduction process. The model was verified by the experiments conducted on several briquettes which were loaded on a corundum crucible. The computed results show that the increase of HCD leads to a decrease in reduction cycle time and an increase in production capacities.