Sustainable tailings utilization: Selective flotation of microfine ilmenite with 2-(hydroxycarbamoyl) decanoic acid

The microfine ilmenite generated during ilmenite beneficiation is challenging to separate from gangue. As a result, it is often discarded directly into tailings, causing wastage of titanium resources. In this study, 2-(hydroxycarbamoyl) decanoic acid (CBHA), a bifunctional collector with strong selectivity and high collecting capacity, was synthesized for the recovery of microfine ilmenite from tailings. When CBHA was used at a low dosage of 800 g/t, the concentrate with a grade of 47.70% and a recovery of 65.74% was achieved. Moreover, the adsorption mechanism was revealed by quartz crystal microbalance with dissipation monitoring (QCM-D), atomic force microscopy (AFM), and density functional theory (DFT). The results showed that the adsorption amount of CBHA on the ilmenite surface reached 510.27 ng/cm 2 and the maximum adhesion force between ilmenite particles reached 22.62 nN, which were more than those on the forsterite surface. This is because the oxygen atoms of CBHA contributed electrons to match with three Ti or Fe sites on the ilmenite surface, resulting in a bicyclic adsorption configuration with an inner ternary ring and an outer polycyclic. In contrast, CBHA adsorbed on the forsterite surface via a single bond or monocyclic structure. In summary, this method promotes sustainable utilization of ilmenite and achieves economic benefits.