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. C-13 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 (R) 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 degrees to 56 degrees, 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 x 61.4% Fe) and less contaminated with quartz (4% SiO2 x 10.2% SiO2), coupled with an increase in Fe recovery from 79.8% x 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.