In this study, the effect of microwave irradiation on ilmenite surface properties and its flotation behavior was investigated. After microwave irradiation, Fe2+ ions on the ilmenite surface are oxidized to Fe3+ ions. XPS analysis indicated that the relative content of Fe3+ increased from 48.5% to 66% after microwave irradiation for 2.5 min. This conversion decreased the ilmenite surface zeta potential in a wide pH range and resulted in the shift of PZC from a pH of 5.4 to a pH of 2.7. FTIR spectra and zeta potential measurements showed that the microwave irradiation enhances the adsorption of oleate ions on the ilmenite Helmholtz layer. The greater stability of chemisorbed ferric iron oleate than ferrous iron oleate resulted in the increase of contact angle and the decrease of surface zeta potential. Therefore, the microwave irradiation pretreatment improves the ilmenite hydrophobicity and floatability in a wide pH range. The maximum floatability of ilmenite occurring at a pH of 63 was 73.5% and 94% for non-irradiated and irradiated ilmenite, respectively. (C) 2014 Elsevier B.V. All rights reserved.