Modeling and Carbon Emission Assessment of Novel Low-Carbon Smelting Process for Vanadium–Titanium Magnetite

The iron and steel industry, as a major energy consumer, was critically required to enhance operational efficiency and reduce CO2 emissions. Conventional blast furnace processing of vanadium–titanium magnetite (VTM) in China had been associated with persistent challenges, including suboptimal TiO2 recovery rates (<50%) and elevated carbon intensity (the optimal temperature range for TiO2 recovery lies within 1400–1500 °C). Shaft furnace technology has emerged as a low-carbon alternative, offering accelerated reduction kinetics, operational flexibility, and reduced environmental impact. This study evaluated the low-carbon PLCsmelt process for VTM smelting through energy–mass balance modeling, comparing two gas-recycling configurations. The process integrates a pre-reduction shaft furnace and a melting furnace, where oxidized pellets are initially reduced to direct reduced iron (DRI) before being smelted into hot metal. In Route 1, CO2 emissions of 472.59 Nm3/tHM were generated by pre-reduction gas (1600 Nm3/tHM, 64.73% CO, and 27.17% CO2) and melting furnace top gas (93.98% CO). Route 2 incorporated hydrogen-rich gas through the blending of coke oven gas with recycled streams, achieving a 56.8% reduction in CO2 emissions (204.20 Nm3/tHM) and altering the pre-reduction top gas composition to 24.88% CO and 40.30% H2. Elevating the pre-reduction gas flow in Route 2 resulted in increased CO concentrations in the reducing gas (34.56% to 37.47%) and top gas (21.89% to 26.49%), while gas distribution rebalancing reduced melting furnace top gas flow from 261.03 to 221.93 Nm3/tHM. The results demonstrated that the PLCsmelt process significantly lowered carbon emissions without compromising metallurgical efficiency (CO2 decreased about 74.48% compared with traditional blast furnace which was 800 Nm3/tHM), offering a viable pathway for sustainable VTM utilization.