METHOD FOR PROCESSING AND INERTING ASHES OBTAINED FROM SOLID RESIDUES SUBJECTED TO THERMAL PROCESSES

摘要

The method consists in separating the ions of heavy metals present in ashes resulting from the incineration of solid residues or from any process involving combustion or thermal destruction reactions, through selective precipitation, in the form of oxides, hydroxides or metal sulfides, of said ions. Said sulfides, oxides or hydroxides are then subjected either to roasting and further reduction with carbon, or a directly to reduction with carbon, so asto obtain the metals in an elemental condition, and inactivated. The remainder of the components is processed with sulfuric and sodium sulfate to obtain gypsum and/or whiting free of heavy metals and other contaiminating agents sensitive to metals and the reagents used in the process. The invention is useful to process ashes of industrial and urban solid waste having a variable content of heavy metals.