Separation of iron bearing minerals from slime by flotation

Abstract

In India, the beneficiation of high grade and medium grade iron ore is limited to mainly washing scrubbing followed by classification, which results in unprecedented generation of slime. The generation of slime is estimated to the tune of 15-20% of the total material mined. The slime contains good amount of iron values in it, which need to be recovered effectively for their usage from material management as well as the environmental nuisance viewpoints. The possibility of recovering valuable iron present in slime using reverse flotation is reported in this study. The sample was first deslimed prior to flotation using classification to remove ultrafines. The deslimed product was subjected to reverse cationic flotation using Cetyl Trimethyl Ammonium Bromide (CTAB) collector for the gangue mineral and starch as depressant for iron oxide. Bench scale flotation experiment was performed by changing operating parameters such as collector concentration, depressant, dispersant concentration, pH and solid-in pulp concentration and impeller rotation. The results showed that CATB has a stronger collecting power to gangue at a dose of 1.5 kg/ton at natural pH, with 46.94% yield having 64.5% iron which can suitably be used for iron making through pelletisaiton.