Novel CO2 Recycling and Reuse Strategy: Reinjection of Hot Metallurgical Off-Gas Into A Vanadiferous Titanomagnetite Ore Blast Furnace

At present, reducing carbon emissions and energy consumption have become the most crucial ironmaking development objectives. Hot metallurgical off-gas (MOG) is one of the most valuable by-product resources containing great underutilized heat and recyclable gas. A sustainable strategy of reinjecting hot MOG as one of the raw materials into the Cr-bearing vanadiferous titanomagnetite ore (CVTO) blast furnace (BF) to achieve its recovery and reuse was proposed and investigated in this study. It is considered feasible according to the obtained results of heat-carbon balance calculations and softening-melting-dripping experiments. First, hot MOG reinjection was beneficial to ameliorate the industrial smelting index and reduce carbon emission and consumption. With the CO2 in the hot MOG increased from 0 to 30 vol%, the softening zone increased from 11 to 135 degrees C, the dripping temperature increased from 1486 to 1534 degrees C, and the melting-dripping zone increased from 150 to 198 degrees C, and it could reduce a considerable carbon rate of 17.2 kg-C/t-Fe. Besides, it could suppress the generation of titanium carbonitride in Ti compounds with a remarkable decrease from 14.4 to 11.9 wt%. Besides, it also improved the high-temperature properties of the titania slag. The melting temperature of the titania slag decreased from 1348.2 to 1331.2 degrees C, and its surface tension increased from 0.302 to 0.551 N/m. Moreover, the corrected viscosity of TiN-bearing slag was calculated, and it showed a profitable decrease from 0.433 to 0.414 Pa.s at 1500 degrees C. In addition, the high-basicity pellet was used to replace the conventional sinter in the above experiments, which was conducive to achieve energy saving and emission reduction in practical applications.