| abstract |
In a method for the treatment, in particular stabilization, of materials containing environmentally noxious constituents, especially from the incineration of waste, in which the materials are treated with ferrous compounds and water, the materials are washed and stabilized chemically using a solution containing ferrous ions (Fe++) which allows the formation of stabilizing ferric oxides (Fe+++) on the materials, the ferric oxide formation being carried out by means of an oxidation under controlled conditions with respect to the nature and the amount of oxidizing agent, temperature and pH, whereafter, if desired, the treated materials are subjected to a thermal after-treatment. A plant for carrying out the said method comprises a silo (2) containing materials containing environmentally noxious constituents; a reactor (1) to which the said materials ar fed; a tank (9) and a return water tank (7) and silos (3, 4) containing ferrous salt solution and, if desired, other chemicals, washing-water and the said chemicals being fed to the said reactor (1), the reactor contents being stirred; a sedimentation tank (5) to which the washing-water is fed; a centrifuge or filter press (6) in which the precipitate formed is dewatered; and means for aerating the water in the said tank (5) for decreasing the pH and oxidation of the water. |