The effect of acid surface pretreatment on the flotation behaviors of ilmenite and titanaugite was investigated with BHA collector and Pb2+ activator. The flotation recovery of ilmenite improved from 6256% to 84.68% at pH 8.0 after pretreated with H2SO4 solution, while that of titanaugite decreased from 35.73% to 0.54%. The results of SEM and ICP analysis showed that the dissolution of Fe, Ca, and Mg elements on titanaugite surfaces was greater than those of ilmenite in the acid solution, especially Fe element. XPS analysis indicated that after the acid surface pretreatment, Ti became a new active site reacted with BHA and the main active sites for ilmenite changed from Fe, Mg, and Ca to Ti and Fe, while the Fe active site disappeared for titanaugite. These changes in the active sites increased the floatability of ilmenite and reduced the floatability of titanaugite. (C) 2020 Elsevier B.V. All rights reserved.