Reduction of Iron-Ore Pellets Using Different Gas Mixtures and Temperatures

Direct reduction of iron ore (DRI) is gaining an increased attention due to the growing need to decarbonize industrial processes. The current industrial DRI processes are performed using reformed natural gas, which results in CO2 emission, although it is less than carbothermic reduction in the blast furnace. Carbon-free reduction may be realized through the utilization of green H-2 as a reducing agent, in place of natural gas. Herein, the effects of various gas mixtures and temperature on the reduction kinetics of the hematite iron-ore pellets are focused on in this work. Pellets are reduced at 700, 800, 850, and 900 & DEG;C in hydrogen and using various gas mixes at 850 & DEG;C. Morphology of the pellets is investigated with the help of scanning electron microscopy and mercury intrusion porosimetry. The effects of temperature and gas composition on the reduction kinetics and porosity of the pellets are discussed. A notable effect of reduction rate on the internal structure of the pellets is detected, slower reduction rate yielded bigger pores offsetting the gas composition. Higher temperature results in coarser pores and higher porosity. Increase of CO content in the gas mix also leads to bigger pore size.

Automated summary

Direct reduction of iron ore (DRI) has gained attention as a way to decarbonize industrial processes. This study focuses on the effects of gas mixtures and temperature on the reduction kinetics of hematite iron-ore pellets. The results show that slower reduction rates lead to larger pores, offsetting the influence of gas composition. Higher temperatures result in coarser pores and higher porosity. An increase in CO content in the gas mix also leads to larger pore size.