The reverse flotation of iron ores is preceded by a desliming stage whose efficiency increases with the use of reagents that promote the dispersion of the pulp. The present study addressed the influence of the type and of the concentration of the dispersant on the dispersion efficiency and on the flotation results. The results were appraised in terms of the slime's particle sizes, the dispersion degree and the Gaudin's Selectivity Index obtained in the flotation experiments. The results show the importance of the dispersion before the desliming stage and also suggest that the selected dispersants must not be quartz depressants. Sodium hydroxide seems to be the most effective among the tested reagents.
Dispersion; desliming; flotation selectivity
