Enhancing the Performance of Iron Ore with Carbide Slag in the CLC Process of Coal

The present study investigated the performance of iron ore mixed with carbide slag (CS) as oxygen carrier in a batch-fluidized bed reactor using Datong bituminous coal as fuel. The effects of mixing mass ratio and reaction temperature on the CLC process of coal were investigated. The results showed that iron ore mixed with carbide slag accelerated the CLC process of coal compared with iron ore alone. Reaction temperature had a crucial effect on carbon conversion of coal, but higher than 900 degrees C resulted in a decreased reactivity of CS-mixed oxygen carrier. Multiple redox cycle tests were also conducted to study the stability of CS-mixed oxygen carrier. It was found that though a continuing decreasing reactivity was observed for CS-mixed oxygen carrier, it still has higher CO2 yield and lower CO yield than those of undecorated one. SEM analysis revealed that sintering occurred on the surface of CS-mixed oxygen carrier, resulting in the deterioration of reactivity. The reason for the promoted performance of CS-mixed iron ore seems to be the catalytic effect of carbide slag on the water-gas shift reaction, converting CO to H-2, for H-2 is more reactive toward iron ore.