A process for treating a waste material coming from aluminum production, the waste material containing contaminants polycyclic aromatic hydrocarbons (PAH) and inorganic fluoride compounds containing fluoride ions, involves flotation of a waste mixture of the waste material in the presence of a surfactant capable of producing PAH-rich micelles that are floated to produce froth containing the PAH-rich micelles; and stabilization of the waste mixture by adding a fluoride ion stabilizer to form stabilized fluoride compounds with reduced solubility in the waste mixture and in a toxicity characteristics leaching procedure test, to produce decontaminated solids containing the stabilized fluoride compounds and a leachate solution.