Fe(III) as an activator for the flotation of spodumene, albite, and quartz minerals

•The effect of Fe(III) on the flotation of spodumene, albite and quartz was studied.•Spodumene, albite and quartz could not be floated only with NaOL.•Presence of Fe(III) could enhance the NaOL adsorption on spodumene surface.

The effect of Fe(III) ions on the flotation of spodumene, albite, and quartz minerals using sodium oleate (NaOL) was investigated by micro-flotation tests, zeta-potential measurement space, pyrene fluorescence spectroscopy and X-ray photoelectron spectroscopy (XPS). These minerals were difficult to float in the presence of NaOL alone. However, when Fe(III) ions were used as the activator, the flotation of the minerals improved. Zeta potential testing found the addition of Fe(III) at pH conditions <8 to reduce the negative charge on the spodumene, albite and quartz surfaces, which supports a mechanism where Fe(III) adsorbs onto these mineral surfaces, resulting in an expected increase in NaOL collector adsorption with a concomitant increase in the flotation recoveries. Subsequent pyrene fluorescence spectroscopy of these minerals in the presence of NaOL collector, with and without Fe(III) activator, showed the mineral surfaces to switch from polar to non-polar.

Graphical abstractSpecies distribution diagrams of 1.5 × 10−4 M Fe(III) (a) and 6.0 × 10−4 M NaOL (b) as a function of pH.Figure optionsDownload full-size imageDownload as PowerPoint slide