The solution-loss reaction of cokes with different reactivity and lump ores during reductive coupling

Five cokes with different reactivities and one mixed coke were coupled with lump ores to explore the changes in deterioration behavior under a CO₂-to-N₂ volume ratio of 30:70. Macro characteristics and microstructures of cokes with different reactivities were analyzed. From a macro perspective, cokes’ solution-loss reaction changed significantly when coke reactivity (CRI) ≈ 35%. Cokes mainly adhered to the uniformly dissolving model when CRI < 35%. Additionally, the average particle size of cokes exhibited negligible changes, merely decreasing from 8.34 to 8.19 mm; however, pore walls suffered severe damage. Cokes mainly adhered to the nuclear-unreacted model CRI > 35%. Besides, the average particle size of cokes has significantly decreased to 7.51 mm, and pore wall damage predominantly occurred on the surface. The conversion of the reaction model increased the difficulty in separating cokes and ores. However, mixed cokes were excellent in slowing down pore wall damage and cokes’ solution loss, which reduced costs in actual production. The order degree of the carbon structure significantly increased at a micro level following the coupling reaction, which led to an enhanced anti-dissolution ability compared to unreacted cokes. Besides, the fringe separation distance of the carbon structure did not change significantly with increased reactivity. However, the order degree gradually decreased accompanied by the decreased anti-dissolution ability.