Abstract
A cationic collector seems to be suitable for the flotation of manganese oxides at pH levels higher than their zero points of charge. Therefore, the adsorption of cetyl trimethyl ammonium bromide (CTAB) on manganosite (MnO), bixbyit (alpha-Mn2O3) and pyrolusite (beta-MnO2) is investigated. The adsorption density of this collector is affected by the change in pH levels.
The amount of CTAB adsorbed on manganese oxides is smaller than expected due to the competition between inorganic ions present in solution (Na+ ions and released Mn2+ ions) and the collector ions. The adsorption isotherms of the collector on the three oxides are of the Langmuir type and its modifications.
The zeta potential of these oxides is reserved in presence of the collector even on the alkaline side. The change in zeta potential after the addition of the collector is greater in case of alpha-Mn2O3 than in the other two oxides. This is due to the lower Mn2+ ions released from alpha-Mn2O3.
The flotation recovery of these oxides is also higher in the case of alpha-Mn2O3 than in both of MnO and beta-MnO2, especially at lower collector concentrations. However, at higher collector concentrations this difference is minimized confirming the depressing action of inorganic cat ions.