Physicochemical Phenomena of CO₂ Injection in Polymetallic Ironmaking

Abstract

Abandoned basic oxygen furnace gas (ABOFG) is a kind of byproduct fuel resource produced in the basic oxygen furnace (BOF) steelmaking process with a high temperature of 1773-1873 K and 20-40% (vol.%) CO and 20-30% (vol.%) CO 2 and is usually ignited and discharged as waste gas (34.7% abandoned rate). The effects and physicochemical phenomena of injecting CO 2 -containing ABOFG into high-Cr-bearing vanadiaÀtitania magnetite ironmaking are investigated. The thermodynamic calculation shows that the ABOFG injection changes the gas partial pressure and the oxygen potential in the slagÀcoke interfaces and suppresses the titanium carbonitride formation. According to the results of soft-eningÀmeltingÀdripping experiments, the content of titanium carbonitride in the high-titanium slag decreases from 2.53% to 1.14% as the CO 2 content in ABOFG increases from 0 to 30%, which is conducive to improving the high-temperature physicochemical properties of molten slag. The recoveries of vanadium and chromium are also improved with the decrease in iron loss. Moreover, the residual coke still maintains a considerable compressive strength with a slight effect from ABOFG injection, which is expected to reduce carbon consumption.