Sulfur incorporation assessment in hot metal from the blast furnaces at Usiminas

Sulfur is an element with strict specifications for certain steel grades, making its control in blast furnace produced hot metal essential.In this regard, the factors influencing sulfur incorporation in the small (BF-S) and medium (BF-M) blast furnaces at Usiminas were analyzed.The methodology included statistical analysis of the sulfur percentage in the furnaces, considering the correlated variables, with statistical comparison between the furnaces (t-test) and multiple regression models for sulfur content prediction in each reactor.Additionally, scenarios for sulfur reduction were simulated by partially replacing coke with charcoal and natural gas.The results indicated that the top pressure in BF-M was the determining factor for its lower sulfur content compared to BF-S, while quaternary basicity was the main explanatory variable for sulfur incorporation in both furnaces.In addition, assuming a constant desulphurisation efficiency, the sulphur content of the hot metal can be reduced by up to 8.8% by partially replacing coke or mineral coal with charcoal or natural gas.