2019 Volume 59 Issue 11 Pages 1982-1990
Ironmaking process by Blast Furnace (BF) method contributes about 70% of CO2 emission and energy consumption in steel works. To aim at the sustainable development and environmental protection, decreasing CO2 emission and energy consumption is always an indispensable task. Using iron ore-coal composite as the raw material of BF is a promising way to mitigate the above issue.
In this study, we conducted an experiment procedure which is to simulate the reduction of an iron ore-coal composite travelling from the top zone to the cohesive zone of BF. Reduction behavior, morphology changes and carburization characteristic of the composites with the variables of C/O (Carbon to Oxygen) ratio were investigated.
As C/O ratio was increased from 0 to 0.6, the reduction rate of composite was accordingly enhanced. It was found that the composite is swelling severely when C/O ratio was lower than 0.4. The swelling occurred in the temperature range from 800°C to 1100°C which was just under the stage of reduction from wustite to iron. The composite is shattering obviously starting from 1160°C when C/O ratio was higher than 0.4. It is because the remained free carbon is surplus in reduced iron, causing shattering and powdering. Hence, C/O = 0.4 was suggested to the composite for being charged into BF.