BIOELECTROMET · Bioelectrochemical systems for metal recovery

Global primary metal resources are rapidly dwindling and the mining and metallurgical industries are increasingly turning to lower grade minerals for metal extraction, typically increasing costs. Innovative environmental metal extraction techniques are required to increase mining sustainability, increase revenues and lower its impact on the environment. In this project, bioelectrochemical technology is proposed as an entirely new method for metal processing with the aim to produce marketable metal-containing (intermediate) products with low environmental impact compared to state-of-the art technologies.In bioelectrochemical technology, microorganisms catalyse the reaction occurring on one or both electrodes of an electrolytic cell. Such cells are called Microbial Fuel Cells (MFCs) when power is produced and Microbial Electrolysis Cells (MECs) when power is required to drive the desired reaction. Recently, it has been shown that Cu2+ is reduced to metallic copper on the cathode of a MFC coupled to the biological oxidation of organic matter and with resulting electricity generation. The proof-of-principle MFC almost completely recovered the Cu2+ in its metallic form (decrease in concentration from 1 g/L to < 1 mg/L) and produced a maximum power density of 0.8 W/m2.Bioelectrochemical technology can be used for the base metals copper, nickel, iron, zinc, cobalt and lead, which are mined, processed and used in large quantities. These metals are ubiquitous in process- and waste streams from the mining and metallurgical industry and therefore application of bioelectrochemistry for these metals has a high impact.Compared to traditional techniques, the use of Bioelectrochemical technology allows high recovery efficiencies, increased metal selectivity and reduced use of energy with in some cases (e.g. copper reduction) electricity production.