Utilization of steelwork waste heaps – recovery of metals by acidic bioleaching

The paper presents the results of preliminary research conducted by the acid bioleaching method, with the use of autochthonous Acidithiobacillus ferrooxidans bacteria and museum strains of Acidithiobacillus thiooxidans, on recovery of metals contained in selected metallurgical waste. The material contained mainly oxidative minerals Fe2O3, SiO2, and Al2O3 as well as lead, zinc, copper and nickel sulphides. Concentrations of the key metals were respectively: zinc 3.46 %, lead 13.8 %, copper 0.4 %, nickel 0.06 %. The works were carried out on a small laboratory scale. The results confirmed that the method is effective. The most effective process of bacterial leaching in the heap was for zinc – a 28 % yield in 96 days.