Adsorption of Surfactant Mixtures during Flotation.

Apart from parameters related to process engineering, the adsorption of surfactants on the surface of minerals and air bubbles is of decisive importance in connection with the separation of mineral raw materials by flotation. This paper reports on investigations made with regard to the effects of mixtures of anionic and nonionic surfactants on the flotation process. Compared with the use of anionic collectors alone, the presence of the nonionic surfactant causes a marked reduction of the surface tension at the liquid/air interface. This process is accompanied by synergistic effects between the two types of surfactants. Moreover, adsorption of the anionic collector on the mineral surfaces is influenced by nonionic surfactants as could be demonstrated by the scheelite/calcite system. The results of physicochemical investigations have been confirmed by flotation tests carried out with natural scheelite ore. The results obtained suggest that recovery and selectivity of flotation can be increased by using mixtures of collectors that include different types of surfactants.