Control of redox processes in the blast furnace

Abstract

Reductive blast-furnace smelting consists of multifactorial oxidative, heat-transfer, smelting, and reducing processes that involve solid carbon and are associated with carburization of the metal. Analysis yields functional relations of the zonal process with controllable parameters of the hot blast. The ore load on the coke, the batch and coke consumption, the reduction rate of iron, and the rate of slag formation may be regulated as a function of the blast flow rate. If the degree of reduction of iron declines from 0.998 to 0.96–0.98, the oxidation of the slag with respect to iron (the FeO content) may be increased to 2–10%, with slowing of the carburization of iron as the melt flows through the coke bed. Slag oxidation may be increased by the injection of powdered iron oxide into the hot blast through tuyeres. As a result, the carbon content in the metal will be 1.5–2.0%, which corresponds to the composition of austenitic steel.