Reduction behaviors and kinetic mechanism of sinter in hydrogen-rich blast furnace

It is an important way to realize low carbon in China’s iron and steel industry by hydrogen-rich blast furnace smelting process. Sinter is the main blast furnace burden, and its reduction characteristics have a significant influence on ironmaking. The reduction behaviors, including reduction index (RI) and low-temperature reduction disintegration index (RDI), and the reduction mechanism of sinter in hydrogen-rich blast furnace were investigated. The results show that RI increased from 82.85 to 95.53 wt.% with an increase in H₂ content from 0 to 30 vol.%, and the main phase of the reduction product was metallic iron. In the research of RDI, when the H₂ content was increased from 0 to 20 vol.%, RDI_+3.15 increased from 69.61 to 75.38 wt.%, and the main reaction was the reduction of hematite to magnetite. At 600-950 °C, the reduction of sinter in CO and hydrogen-rich atmospheres (H₂:CO = 2) was both controlled by the first-order reaction model, and the apparent activation energy was 33.64 and 44.57 kJ/mol, respectively.