The selective flotation of ilmenite from olivine using an acidified water glass (AWG) as a depressant and sodium oleate (NaOL) as a collector has been studied. Through a series of micro-flotation tests, batch flotation tests, adsorption experiments and zeta potential measurements, the selective depression performance and depression mechanism of the AWG were demonstrated. The micro-flotation results indicate that the AWG at a molar ratio 1:3 of oxalic acid to water glass (WG) exhibits the maximum selective depression on olivine. The selective flotation of ilmenite from olivine can be better achieved using an AWG as depressant rather than WG in the artificially mixed minerals flotation experiments. Batch flotation test results indicate that, compared with the depressant WG, the depressant AWG not only increases the recovery and grade of the Ti concentrates by 7.74% and 3.82%, respectively, but also decreases the depressant consumption by two-fifths. Adsorption tests and zeta-potential measurements indicate that the AWG exhibits a stronger adsorption on the surface of olivine than ilmenite. The adsorption of the AWG on the olivine surface prevents the mineral from adsorbing collector NaOL due to electrostatic repulsion. (C) 2016 Elsevier B.V. All rights reserved.