resulting in ilmenite flotation; that the Ca and Mg on the titanaugite surface chemically reacted with sodium oleate, and that the Mg on the forsterite surface chemically reacted with sodium oleate under acidic condition. However, sodium oleate mainly reacted with the Ca and Mg on the titanaugite surface, whereas sodium oleate mainly reacted with the Mg on the ilmenite and forsterite surfaces under alkaline conditions.