Activation of ilmenite flotation by Al3+ in the benzohydroxamic acid (BHA) system

Abstract

Pb2+ has been extensively studied as an activator in ilmenite flotation. However, because of its toxic nature, it is necessary to urgently devise an environmentally friendly metal ion to replace Pb2+. This study developed a new scheme for the activation of ilmenite by Al3+ in a benzohydroxamic acid (BHA) system. The effects of the sequential dosing of Al3+ and BHA and the addition of pre-formed Al-BHA complexes were compared based on the results of micro-flotation, zeta potential, adsorption, and XPS analysis; the activation mechanism was investigated. Flotation tests showed that Al3+ promoted ilmenite up-floating, and a maximum recovery of 86% could be achieved using the Al-BHA complexes at pH = 8. Zeta potential and adsorption tests illustrated that the introduced Al3+ activator was adsorbed on the ilmenite surface, and the pre-formed Al-BHA complexes could stabilize BHA adsorption more effectively than the sequential addition of Al3+ and BHA. XPS analysis showed that the Al-BHA complexes generated new Al-O bonds and were chemisorbed at both the Fe and Ti active sites. As a result, the connection between ilmenite and BHA was strengthened by the formation of more stable -Fe-O-Al-BHA and -Ti-O-Al-BHA bonds. Therefore, Al-BHA complexes demonstrated great potential to enhance the activation of ilmenite flotation in the BHA system.