BIOLEACHING OF Zn Pb Ag SULPHIDIC CONCEN

Polymetallic or complex Zn-Pb-Ag sulphide concentrates can be treated by bioleaching combined with proper hydrometallurgical processes. The objective of this study was to explore the efficacy of indirect bioleaching as a biotechnology for bioprocessing zinc and polymetallic concentrates. Utilizing a methodology based on ferric leaching facilitated by bio-regenerated ferric sulphate solution, the study highlighted significant advantages such as high metals recovery and rapid extraction kinetics, achieving full metal extraction within 4-5 hours. The process also allows for the oxidation of sulphur to elemental sulphur, thereby avoiding the generation of sulphuric acid while leaving pyrite mineral untouched. Results demonstrated that indirect bioleaching not only utilizes conventional reactors but also operates without the requirement for aeration, thus providing a more environmentally friendly approach compared to traditional pyrometallurgical techniques. This innovative method shows promise for the future bioprocessing of a wide variety of zinc and lead polymetallic mineral deposits found in Europe and around the world, stressing the importance of developing eco-friendly mining technologies.