The activation mechanism of lead ions in the flotation of ilmenite using sodium oleate as a collector

The flotation behaviors of ilmenite untreated or treated with lead ions using sodium oleate as a collector were studied. The results of micro-flotation experiments reveal that ilmenite shows good floatability at pH 6-8. Compared with the flotation recovery of ilmenite untreated with lead ions, ilmenite floatability can be enhanced, and the resulting increase in recovery can surpass 30% after the addition of lead ions. The results of zeta potential tests show that the isoelectric point of ilmenite can change from 5.2 (untreated) to 7.8 (treated), which is beneficial for the interaction between ilmenite and the collector and increases its floatability. Adsorption measurements show that the adsorption amounts of ilmenite treated with lead ions are higher than those of untreated ilmenite. XPS tests show that after activation with lead ions, the relative contents of iron and titanium on the ilmenite surface, which play leading roles in ilmenite flotation, increase by 5.9% and 4.6%, respectively. At the same time, changes in binding energy are more visible after ilmenite is pretreated with lead ions and subsequently treated with sodium oleate. Within the optimal flotation pH range, oleate species (RCOO−, (RCOO)22-, (RCOO)2H−) can mainly react with iron on the ilmenite surface through chemical adsorption in addition to electrostatic effects.