Flotation of hydrophobic contaminants from soil

Application of flotation for the removal of hydrophobic compounds from soils was studied. Bench scale flotation tests were conducted on artificially contaminated soil, using both a conventional mechanically agitated machine and a flotation column. Flotation parameters tested include collector type, conditioning time, flotation time, surfactant dosage, pulp pH, solid/liquid ratio in conditioning and pulp temperature. It was found that, with conventional flotation, 74% removal of the contaminant was achieved from soil particles in the range of 75–830 μm; with column flotation up to 80% of oil could be removed from the 250–830-μm soil fraction, and 65% from the 75–830-μm fraction. Flotation was found to have considerable potential for cleaning up contaminated soils.