Review on coal-based reduction and magnetic separation for refractory iron-bearing resources

The application of coal-based reduction in the efficient recovery of iron from refractory iron-bearing resources is comprehensively reviewed. Currently, the development and beneficiation of refractory iron-bearing resources have attracted increasing attention. However, the effect of iron recovery by traditional beneficiation methods is unacceptable. Coal-based reduction followed by magnetic separation is proposed, which adopts coal as the reductant to reduce iron oxides to metallic iron below the melting temperature. The metallic iron particles aggregate and grow, and the particle size continuously increases to be suitable for magnetic separation. The optimization and application of coal-based reduction have been abundantly researched. A detailed literature study on coal-based reduction is performed from the perspectives of thermodynamics, reduction kinetics, growth of metallic iron particles, additives, and application. The coal-based reduction industrial equipment can be developed based on the existing pyrometallurgical equipments, rotary hearth furnace and rotary kiln, which are introduced briefly. However, coal-based reduction currently mainly adopts coal as a reductant and fuel, which may result in high levels of carbon dioxide emissions, energy consumption, and pollution. Technological innovation aiming at decreasing carbon dioxide emissions is a new trend of green and sustainable development of the steel industry. Therefore, the substitution of coal with clean energy (hydrogen, biomass, etc.) for iron oxide reduction shows promise in the future.