Influence of Process Parameters on Chromium Metallization During Chromite Pellet Pre-Reduction

The present study compares the effects of temperature, holding time, and nominal carbon excess on the pre-reduction of Donskoy chromite pellets with semi-coke. FactSage equilibrium calculations were interpreted alongside three laboratory series with different baselines. At 180 min with activated bentonite and 25% carbon excess, chromium metallization increased from 58.5% at 1350 °C to 87.0% at 1500 °C. At 1400 °C with attapulgite and 10% excess, extending holding time from 195 to 210 min increased chromium metallization from 70.6% to 82.8%, while residual carbon decreased from 4.96 to 4.00 wt.%. At 1500 °C and 180 min with activated bentonite, increasing excess from 15% to 25% increased chromium metallization from 68.9% to 87.0% and residual carbon from 2.30 to 4.74 wt.%. These condition-specific endpoints do not establish factor interactions, an optimum regime, or a kinetic mechanism. Unavailable uncertainty estimates limit quantitative interpretation. Equilibrium predictions and elemental maps do not independently verify the experimental phase sequence. Any industrial benefits, including chromium recovery, energy consumption, and continuous-process performance, require further validation.