[Treatment of PAH-contaminated aluminium wastes by flotation using amphoteric surfactants]

The aluminium industry produces wastes polluted with polycyclic aromatic hydrocarbons (PAH). The most important PAH found in these wastes is benzo(b,j,k)fluoranthene (BJK) at concentrations exceeding the permitted levels (>1000 mg kg(-1)). The objective of this research was to compare the performances of amphoteric (BW and CAS) and non-ionic surfactants (Triton X-100 and Tween 80), at a concentration of 0.5% (w w(-1)), for PAH removal (and particularly for BJK) during washing treatment of aluminium industry wastes. The best removal yield of BJK (35%) has been measured during treatment with CAS. The efficiency of this surfactant has been further improved by using a flotation process. Flotation tests have also been realized at different CAS concentrations (0.1, 0.2, 0.25 and 0.5% w w(-1)) and using different total solids (7, 10, 15 and 20% w v(-1)). The highest BJK removal yield (68%) has been obtained using 0.5% CAS and a total solids concentration of 15%. The rate of hazardous wastes produced in these conditions represents 10% of the initial weight of aluminium wastes treated.