MiCCuR: Microbial consortia for enhanced copper recovery

Copper is a much-used metal in Europe and around the world, which is traditionally extracted from ores using costly and environmentally damaging processes. In many countries, more gentle processes are already being used for copper extraction: Certain bacteria draw 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", significant amounts of metal are extracted in many countries today. About 15 - 20 percent of the copper produced worldwide is made available in this way. However, as the demand for metals increases, more copper deposits need to be accessed. One of the largest resources is chalcopyrite, a poorly soluble compound of copper, iron and sulphur. Biological methods have hardly been used here so far because of the slow release of the metal.

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.

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. Preliminary research has shown that certain types of bacteria inhibit the process, while others accelerate it. In MiCCur, biological tweaks will now be used to promote the microbial communities that are particularly good at releasing the copper. The team has already been able to show that a higher concentration of salt will inhibit the growth of the undesirable bacteria. The scientists also plan to influence the communication between the bacteria. They intend to use certain substances that the bacteria use as language - similar to animal pheromones.

Within the MiCCur project, the optimised procedure will not only be tested on a small laboratory scale. To show that the newly developed process can actually be used industrially, the team is collaborating with the Coyancura Mine in Chile. There, the optimised microbial communities can be tested on pilot waste dumps. 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 community operates.

In this project, G.E.O.S. conditions the leaching solutions and separates the valuable metals, especially copper, but also accompanying elements such as silver, nickel and cobalt. In addition, all technical, economic and ecological issues related to the leaching processes are brought together. Last but not least, the project also contributes to international cooperation. Latin America, represented here by Chile, as well as South Africa and Europe are working together to make hitherto scarcely tapped resources usable for the world market while significantly reducing the ecological footprint.

Video: MiCCuR 2022