Selective leaching of zinc from basic oxygen steelmaking dust by organic acids

The organic acids leaching process was performed to compare the leaching efficiencies of zinc and iron from a basic oxygen steelmaking dust by oxalic acid, citric acid, acetic acid, propionic acid, butyric acid, and valeric acid and the effect of acid concentration and liquid/solid stoichiometric ratio was further studied. The results showed that the six organic acids had different leaching behaviors for zinc and iron and oxalic acid was easy to form sediment on the dust surface to hinder the leaching. Citric acid had complexing properties, which was conducive to the leaching, but the leaching selectivity of zinc is poor. The leaching selectivity of the other four alkyl acids increases with the increase of carbon chain, and the effect of butyric acid was better. The preliminary optimization of butyric acid leaching led to zinc and iron leaching rate of 51.2% and 0.5%, respectively, and the mass ratio of zinc to iron in the leachate was 12.6. A butyric acid leaching technology was designed to provide a reference for future treatment of zinc-containing steelmaking dust. The high-efficiency selectivity of butyric acid has good potential for application, and it is significant for the steel industries to implement sustainable development strategy.