Scenarios for Sustainable Management of a Solid Release from a Hydrometallurgical Zinc Treatment in the Democratic Republic of Congo

摘要

cqvip:The treatment of zinc ores at the UZK(Kolwezi Zinc Factory),in the DRC(Democratic Republic of Congo),has generated a deposit of solid releases rich in recoverable metals,but presented an environmental risk given the conditions of its storage.The results of chemical analyses by X-ray fluorescence have shown the presence of base metals recoverable in significant proportions in these releases,which contain on average 17%zinc and 3.5%copper.In addition,X-ray diffraction analyses have identified the main minerals:franklinite,willemite and sphalerite.The environmental risks are real,because the results of the availability tests for leaching have revealed significant zinc and copper extraction rates for a liquid to solid ratio of 100 and those of landfill compliances show that although under European Directive 2003/33/EC,these discharges are dangerous and must be treated under conditions which respect the environment.Following an environmental risk assessment,two scenarios for reprocessing these discharges are envisaged and will be compared from a technical,economic and environmental point of view,including their feasibility in the context of the DRC.The two processes would be on the one hand a hot acid attack in two or three stages and on the other hand a mixed digestion-roasting treatment followed by leaching with water.