MiCCuR: Environmentally friendly copper extraction through microbes

1.3 million euros for new EU-ERA-MIN project "MiCCuR"

International team with the involvement of G.E.O.S. aims to improve biotechnological processes for ore mining

Copper is a widely used metal in Europe and around the world, which is traditionally extracted from ores using a costly and environmentally harmful processes. In several countries, more gentle processes are already being used: Certain bacteria draw their energy from the recycling of metals and sulphur compounds that make up the ores. These natural metabolic processes lead to copper being leached out.

Through these processes, known as "biomining" (bio leaching), significant amounts of metal are extracted in many countries today. About 15 - 20 percent of the copper produced worldwide is extracted this way. However, as the demand for metals increases, more copper deposits need to be developed. One of the largest resources is chalcopyrite, a poorly soluble compound of copper, iron and sulphur. Because of the slow metal release, hardly any biological processes have been used heretofore.

An international team of researchers from Sweden (Linnaeus University), South Africa (University of Cape Town), Chile (Pontificia Universidad Católica de Chile) and Germany (G.E.O.S., TU Bergakademie Freiberg, Ruhr-Universität Bochum) is pursuing new approaches to increase the efficiency of chalcopyrite mining. The project is being funded within the framework of the EU initiative ERA-MIN2 with a total of 1.3 million euros. ERA-MIN2 supports research initiatives that deal with the resource-efficient extraction of raw materials. In the process, each state government funds "its" national scientists.

As part of the MiCCur project (Microbial Consortia for enhanced Copper Recovery), the researchers aim to develop special processes to accelerate the slow leaching of copper from chalcopyrite. Earlier work has shown that certain types of bacteria inhibit the process, while others accelerate it. In MiCCur, biological tricks will now be used to boost precisely those microbial consortia that are particularly good at releasing the copper. The team has already been able to show, for example, that a higher salt content inhibits the growth of undesirable bacteria. The scientists also plan to alter the ways in which the bacteria communicate with each other. They intend to use certain substances that are used by the bacteria as language - similar to animal pheromones.

As part of MiCCur, the improved process will not only be tested on laboratory scale. To show that the newly developed process can in fact be used on an industrial level, the team is collaborating with the Coyancura Mine in Chile. There, the optimised microbial communities can be tested on a pilot scale bioheap. A special feature of the research project is that each step is to be investigated using biological procedures. In this way, the scientists want to understand how exactly the microbial consortia works.

In this project, G.E.O.S. will be processing the leaching liquids and separating the valuable metals, especially copper, but also by-elements such as silver, nickel and cobalt. Furthermore, all technical, economic and ecological issues regarding the leaching processes will be jointly coordinated by G.E.O.S.. Last but not least, the project serves to promote international cooperation. Latin America - in this case represented by Chile- as well as South Africa and Europe are cooperating to make raw materials available to the global market that were previously almost impossible to exploit. At the same time the aim is to significantly reduce the ecological footprint.