Flotation of hematite using 18-carbon fatty acids

Abstract

The aim of this study was to investigate whether commercially available mixtures of the 18-carbon fatty acids could be used as flotation reagents for oxide minerals. These fatty acids are relatively insoluble, but the unsaturated fatty acids are known to have good collecting properties under alkaline pH conditions. Flotation recovery of a sample of hematite using these fatty acids was investigated over a wide pH range. Chemisorption was identified as the dominant mechanism of adsorption in the alkaline pH range, but physical adsorption of negatively charged surfactant moieties could well contribute to hematite flotation in the acidic pH region. There appeared to be a controversy between the higher collecting power of the surfactants with an increasing number of double bonds/molecule and their associated increased hydrophilic character and susceptibility to oxidation. It was shown that commercially available mixtures of 18-carbon unsaturated fatty acids are suitable flotation reagents for use in the recovery of oxide minerals giving high mineral recoveries.