Abstract

This article study the mechanism of quartz flotability in the presence of non-modified starch and cationic collectors. Depressant behaviour effect of natural polymer is shown in lightly alkaline or neutral solutions, depending on concentration and collectors hidrocarbon chain length. Specific interaction of quartz-starch produce a deplacement of mineral P.I.E. to the more acid values of pH. The streaming potential of quartz in the presence of collectors and starch, approach to zero regarding collector concentration and the value of pH. The adsorption of starch on the mineral surface at 25°C indicate lower densities at pH 9,5, which explain the high flotability of quartz at this pH, according with results obtained by others authors.