Experimental and mechanistic study on iron extraction from high-iron red mud under multiple physical field coupling conditions

Abstract

Red mud is a solid waste discharged in the process of alumina production, and how to realize the efficient recovery of its iron is an urgent problem to be solved. In this study, the iron extraction test and mechanism study of high-iron red mud were carried out under the coupling conditions of multiple physical field (microwave field, gas-solid flow field and temperature field) with biomass as the reducing agent. The test results showed that under the optimal conditions, an iron concentrate with a yield of 78.4%, an iron grade of 59.23%, and a recovery rate of 86.65% was obtained. The analyses of XRD, XPS, TEM, and SEM-EDS showed that during the roasting process, the hematite in the high-iron red mud was completely converted to magnetite, and the biomass produced the reductant that provided the magnetization reaction; A large number of cracks and pores appeared in the surface of the hematite reduction product particles, which helped to induce iron minerals to undergo effective mineral phase transformation. The above study provides ideas for the phase transformation and efficient recovery of iron minerals in red mud.

Keywords

multiple physical field / high-iron red mud / biomass / mineral phase transformation / iron extraction

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Central South University