Diagnose for valorisation of reprocessed slag cleaning furnace flue dust from copper smelting

Slag cleaning furnace flue dust is generated in the cleansing of copper slag and their reprocessing produces wastes considered hazardous materials. Due to their high metals content their disposal not offers any economic either environmental benefit. In view of this fact, the main objective was to gain basic information for the reuse of these wastes in different fields. So, an exhaustive characterization of two wastes have been carry out in order to determine their composition, mineral phases, particle size distribution and leaching capacity of contaminants, as an indispensable preliminary step to choose the best available technology to recover the metals. Both waste contain very fine particles size and are mainly enriched of Zn, Pb and Fe. Zincite (ZnO) is the major mineral phase in which Zn is presented in both wastes. Pb is found as carbonate (PbCO3) or sulphate (PbSO4). On the other hand, iron is presented as oxides and hydroxides (Fe3O4 and FeOOH). The results show that both wastes are an important secondary resource of Zn and Pb and pyrometallurgy and hydrometallurgy appears to be attractive options for the management of these hazardous materials. The value associated with the Zn and Pb recovery contributes significantly to the economic viability of the activity, since these processes are widely used to reprocess secondary source waste with similar composition to the studied wastes. In this sense, and taking into account a best available technology environmental friendly, the hydrometallurgy would ensure the best option for Zn and Pb recovery from the wastes studied.