Comparative Study of Iron Ore Reduction by Volatile Matter from Non-Coking Coal and Walnut Shell: Part II: Kinetic Analysis

This study investigates the reduction of iron ore pellets using walnut shell and non-coking coal as inexpensive reductants. Experiments were conducted at ۱:۱ and ۲:۱ reductant-to-ore ratios and temperatures up to ۹۰۰ °C. Maximum reduction degrees of ۴۸% (walnut shell) and ۶۴% (nut coke) were achieved at the higher ratio, which are lower than thermodynamic predictions due to kinetic and operational limitations. Kinetic analysis using the shrinking core model identified ash-layer diffusion as the rate-controlling step, with activation energies ranging from ۱۶۷ to ۲۲۰ kJ/mol, consistent with diffusion-controlled heterogeneous reduction. The results highlight the potential and constraints of biomass reductants in direct ironmaking processes.

کلیدواژه ها:

Reduction Degree ، Walnut Shell ، Non-coking Coal ، Shrinking Core Model ، Diffusion Control