Effect of lead ions on the selective flotation of ilmenite against titanaugite using octyl hydroxamic acid as collector

Froth flotation, the main process for separating ilmenite, depends heavily on the performance of flotation re-agents. Herein octyl hydroxamic acid (OHA) and lead nitrate served as collector and activator were introduced into the ilmenite-titanaugite flotation system. The adsorption of Pb2+ on ilmenite and titanaugite surfaces and the subsequent influence on their flotation behaviors were systematically investigated by AFM, FTIR and XPS. Microflotation results showed that Pb2+ could selectively enhance the floatability of ilmenite rather than titanaugite. Contact angle and AFM measurements verified that OHA selectively adsorbed onto the surface of Pb2+- modified ilmenite and increased its hydrophobicity. As characterized by zeta-potential and XPS analyses, lead ions adsorbed onto ilmenite surfaces via chemisorption and physisorption, forming lead-containing complexes, while only Pb2+ physisorption occurred on titanaugite surfaces. Consequently, the active sites on ilmenite surfaces were dramatically increased and leading to the denser adsorption of OHA collector which contributed to the flotation of ilmenite.