China Nonferrous Metallurgy

Blast furnace ironmaking process has some problems, such as long process, high energy consumption and strong dependence on metallurgical coke. It is of great significance to develop green and low-carbon non-blast furnace ironmaking process. The current study investigated the flash reduction behavior of fine iron ore in methane atmosphere at 1450-1550K. The effects of reduction temperature and methane concentration on the metallization rate were investigated, and the microstructure of the reduction products was observed to analyze the mechanism of flash reduction. The results showed that the metallization rate reached 90.0% when the reduction temperature was 1550K, CH4 concentration was 7.5% and the reduction time was 5.49s. The increase of reduction temperature and reduction time increased the metallization rate of fine iron ore. The solid carbon generated from the pyrolysis of methane was attached to the surface of particles, which was deposited on the surface of the reduction product, promoting the reduction of iron oxides and carburizing of metal iron. The carburization process decreased the melting point of metal iron, making the reduction product from irregular shape to spherical shape. Cross-sectional morphology was the structure of a dense iron layer wrapping the unreacted iron oxide. The reduction of FeO at the FeO/Fe interface was mainly accomplished by [C] in Fe.