Remelting of contaminated oxidised aluminium scrap in rotary furnaces
under a salt slag leads to a flue dust which consists of sublimed alka
line metal chlorides and fluorides, lime (which is added to the flue g
as for adsorption purposes) and alumina. Beside minor amounts of heavy
metals it contains free and organic carbon (e.g. in form of PCDD and
PCDF) and metallic aluminium. A combined process is proposed in which
the toxic organic compounds are destroyed by a pyrometallurgical treat
ment either at low or high temperatures. The valuable substances are r
eclamated in form of industrial salt by hydrometallurgical process met
hods.