Bioreactor Process Optimization for Bioleaching of Fine-Grained Residues from Copper Smelting

摘要

Theisen sludge, a fine-grained by-product from copper smelting is a secondary resource for the winning of strategic elements by metal-oxidizing acidophilic bacteria. Screening for cultures, that grew in presence of the toxic heavy metals containing fly ash was successfully performed. Small scale experiments in shaking flasks with subsequent analysis of the pregnant leaching solution (PLS) revealed biological extraction of the major (zinc and copper) and minor metals (cobalt and rhenium). Results were confirmed by XRF analyses of the leaching residue. The bioleaching approach was up-scaled in stirred tank bioreactors under controlled conditions. Optimization of metal-extraction rates will be achieved by regulation of process-parameters, predominantly the redox-potential.