Interaction Between Nonionic Surfactants and Alkyl Amidoamine Cationic Collector in the Reverse Flotation of Iron Ore

This paper evaluates the performance of four ethoxylated nonionic surfactants (nonyl phenol vs. C13 alcohols) to act as ancillary collectors with Alkyl Amidoamine (AAA) in the reverse flotation of quartz at pH8 to concentrate iron ores. Compared to 100% AAA, the blend composed of 80% AAA (Flotinor®5530) plus 20% of isotridecyl alcohol ethoxylated with five groups of ethylene oxide (DP-210 RO) improved quartz recovery (from 54% to 63%, p < 0.05) by increasing contact angle (from 55◦ to 56◦, p < 0.05) and decreasing induction time (26 ms to 23 ms,p < 0.05). Compared to 100% AAA (200 g/t), the blend (160 g/t of AAA + 40 g/t of DP-210 RO) improved the flotation performance of iron ore, yielding richer hematite concentrate (65.3% Fe × 61.4% Fe) and less contaminated with quartz (4% SiO2 × 10.2% SiO2), coupled with an increase in Fe recovery from 79.8% × 81.6% in the sunken product as well as SiO2 recovery from 91.7% to 96.9% in the froth. Results from zeta potential, the hydrodynamic diameter of reagent droplets, and the surface tension of the solution provide insights into the synergism between AAA and DP-210 RO.