Kinetics of hydrogen reduction of magnetite concentrate particles at 1623–1873 K relevant to flash ironmaking

Abstract

The reduction of magnetite concentrate particles by H2 has been investigated in drop-tube reactor (DTR) to obtain a rate equation that can be applied to the design and analysis of an ironmaking flash reactor. The temperature range in this work is 1623 to 1873 K, where the magnetite concentrate particles become molten droplets. Full reduction of the magnetite concentrate is achieved at a residence time greater than 4 s and H2 partial pressure of 0.15 atm within the temperature range investigated. Computational fluid dynamics analysis is used to improve the accuracy of the obtained rate expressions where the variation of particle temperature is taken into consideration. The reduction of magnetite concentrate particles in this temperature range is best described by the nucleation and growth model with an Avrami parameter n = 1 and a first-order dependence on the partial pressure of H2. The activation energy of reaction is 180 kJ mol−1.