Flotation of zinc and cadmium cations in presence of manganese dioxide

The subject of this paper is the flotation (foam separation) of zinc and cadmium cations in presence of manganese dioxide precipitate. The removal of zinc cations by adsorbing particulate (particles) flotation (with Tween 80) is higher than that of cadmium ones. It increases both with the increase of the concentration of manganese dioxide precipitate, and that of the nonionic surfactant (Tween 80). The removal of zinc cations by ion flotation (with sodium soaps) is lower than that of cadmium ones. It does not change with the increase of the manganese dioxide precipitate concentration. It increases, however, with the increase of the anionic surfactant (sodium laurate and stearate) concentration. The mechanism of foam separation was discussed on the base of the interaction: (a) between the surface of the manganese dioxide precipitate and the metal cations; (b) between the surface complexes of the precipitate–metal cations and Tween 80; (c) between the metal cations and the sodium soap.