The upgrading of low-grade iron ore: optimization of recovery and reduction of feed volume

The present study investigated the potential for iron recovery from magnetite-bearing iron ore tailings at the Sangan Company’s old dumps, aiming to reduce environmental challenges through wet magnetic separation as a pre-beneficiation stage. This method selectively removed coarse gangue while maximizing magnetite recovery. A full factorial experimental design evaluated the effects of magnetic field intensity (۱۲۰۰, ۲۷۰۰, ۳۴۰۰ gauss), drum speed (۱, ۱.۴ m/s), and pulp solids content (۲۵%, ۳۵%). Concentrate analysis was performed using titration and Satmagan methods. Partial Least Squares (PLS) modeling revealed that higher magnetic field intensities significantly improved magnetite recovery, enabling a feed mass reduction of ۱۸–۲۲% with negligible magnetite loss (~۲–۳%). Magnetite recovery from tailings represents a novel approach, achieving up to ۹۷.۲۱% recovery under optimal conditions. Davis Tube tests confirmed that lost magnetite, with iron grades below ۱۳.۶۳%, is unsuitable for the final concentrate, enhancing overall concentrate quality by its removal. This pre-upgrading process improves concentrate quality, reduces operating costs, and supports sustainable tailings management.

Keywords:

Low-grade iron ore , Magnetic Separation , upgrading , Pre-processing , Design of Experiments