Evaluation of Dry Processing Technologies for Treating Low Grade Lateritic Iron Ore Fines

ABSTRACT

Dry processing options, involving the use of a circulating air classifier and thermal roasting (advanced microwave-assisted magnetizing roasting), followed by magnetic separation using an Induced Roll Magnetic Separator (IRMS), were evaluated for upgrading low-grade hematite-goethite iron ore fines. The novel magnetizing roast was conducted under reducing conditions using CO/CO₂ gas mixtures which converted the initial goethite-rich ore into a magnetite-rich ore. From a feed sample containing 54.5% Fe, 2.10% SiO₂, 7.97% Al₂O₃, 0.97% TiO₂ and 0.13% P with a density of 3.87 g/cm³ and 80 wt% passing 675 µm, a high-grade IRMS magnetic product of 62.0 wt% Fe was obtained with a yield of 71.6 wt% and around 82 wt% recovery of iron units.

KEYWORDS:

• Low-grade iron ore
• dry beneficiation
• circulating-type air classifier
• microwave-assisted magnetizing roasting
• magnetic separation

Acknowledgments

The authors acknowledge Dr Nathan Webster (QXRD) and Mr Keith Vining of CSIRO for valuable discussions and assistance in carrying out this investigation. We would also like to thank the reviewers for their thoughtful comments and efforts towards improving our manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was a collaborative project supported by CSIRO Mineral Resources and NMDC Limited of India.