Insights into the adsorption mechanism of benzohydroxamic acid in the flotation of rhodochrosite with Pb2+ activation

The adsorption mechanism of benzohydroxamic acid (BHA) on rhodochrosite surfaces under Pb 2+ activation was systematically studied through a series of experiments. Comparing to the results of only BHA treatment, Pb 2+ ions raised the adsorption amount of BHA and the floatability of rhodochrosite, especially at pH 8.0–9.0. It was proven that Pb(OH) + was deemed as the critical species to adsorb onto rhodochrosite surfaces in the form of lead-containing complexes. Afterwards, rhodochrosite surfaces became much more activated for BHA adsorption. BHA collector reacted with adsorbed-Pb and Mn species of rhodochrosite surfaces, and the charged hydroxamic acid also adsorbed onto rhodochrosite surfaces through electrostatic attraction and co-adsorption. Besides, lead hydroxamate complexes generated in suspension had excellent adhesions on rhodochroganite surfaces. It was apparent that the BHA adsorption was strengthened under the activation of Pb 2+ ions. BHA collector matching with Pb 2+ ions had great potentials to improve the flotation recovery of rhodochrosite.