Zinc oxide production through reprocessing of the electric arc furnace flue dusts

The smelting of slag in view producing copper and cobalt alloys achieved at the “Big Hill Smelter in Lubumbashi” (DRC) generates Electric Arc Furnace flue dusts as by-product. These EAF dusts are highly toxic wastes since they consist essentially of low-grade zinc oxide powders wherein one finds lead (9.11%) as the major impurity. That is why, they are looked at as hazardous wastes that must be either stored in specialized landfills or reused as secondary raw materials. This research aims at producing zinc oxide through reprocessing of the EAF flue dusts. The treatment suggested is based on three operations: leaching (290 mg/L H2SO4, 130 min) of the EAF flue dusts in view dissolution of zinc (99.42%), precipitation of zinc (90%) at pH 7.5 with sodium hydroxide and calcination (300 °C, 15 min) to produce zinc oxide (93.39%). The recovery of zinc oxide from these hazardous wastes is a cost-saving method for their sound management and disposal. It is though that this practice could contribute to the conservation of resources and the environment safeguard.