Energy-efficient reduction of iron from its ores

Abstract

Terra thermodynamic-modeling software is used to investigate the solid-phase reduction of iron, in two stages: (1) reduction in an elementary model system; (2) reduction of iron from ore by coal. In the first stage, analysis of the redox conditions in the Fe–C–O system permits determination of the boundaries of the reductive, transition, and oxidative regions and the corresponding values of the oxygen/carbon ratio. Analysis of the reducing properties of coal by calculating the equilibrium compositions in the range 373–1873 K on the basis of Terra software shows that, within that range, the gas composition is practically the same for all the types of coal considered; only the content of volatiles is different. Sharp increase in gas volume begins at 673 K and ends at 1073 K. In the second stage, thermodynamic modeling permits the determination of the optimal consumption of poorly clinkering SS coal, long-flame D coal, and 2B lignite for complete reduction of iron from ore of specified composition.