Through its venture capital fund BMW i Ventures, the BMW Group has taken a stake in Colorado-based Jetti Resources. Founded in 2014, Jetti Resources has developed a pioneering process for copper extraction that utilizes previously unused ore from existing copper mines. BMW’s goal is to foster responsible and resource-conserving copper extraction to address rising demand in a more sustainable way.

As copper is a vital raw material to produce electric drivetrains in EVs, demand is forecasted to grow substantially in the coming years. As early as 2030, at least half of BMW Group’s global sales will consist of fully electric vehicles.

Jetti Resources has developed a catalytic leaching technology that enables the extraction of copper from previously unexploited ores. Around 70% of the world’s copper resources are bound up in those primary sulfide ores. Material, previously stored in dumps and considered waste, can now be tapped into with this new form of resource-conserving extraction.

Leaching for copper extraction generally works by dripping a dilute acid solution through piles of ore to create an environment in which rock-eating and iron-oxidizing microbes (known as lithotrophs and ferroxidants) can naturally break down and oxidize the ore. The resulting copper-rich solution is then processed to produce high purity copper cathodes.

However, the leaching described above has been limited to just oxide and secondary sulfide ore types and hasn’t worked on more prevalent primary sulfide ores due to the effect of an inhibitory layer (the “passivation layer”) that forms on the surface of the mineral preventing leaching from occurring effectively.

Jetti’s novel technology works by breaking through the passivation layer effect, allowing the oxidation of the ore and thereby generate economic yields of copper. Earlier this year, Jetti and the University of British Columbia (UBC) published the research that underpins Jetti’s technology in a paper in Acta Materialia.

In the study, Jetti’s team used electrochemical analysis to discover that chalcopyrite is an n-type semiconductor in an accumulation state, not in a depletion state as has been commonly assumed to date. Jetti’s researchers demonstrated how during oxidative leaching, such as bioleach or chloride leach processes, a copper rich surface forms on the surface of the chalcopyrite. This rich product layer is a p-type semiconductor.

Careful analysis of the data allowed the scientists to discover that, as leaching progresses, the n-type semiconductor chalcopyrite surface and the p-type semiconductor of the product layer form a p- n junction diode which hinders the electrochemical leaching process as it blocks the transfer of electrons. This novel understanding of the passivation layer demonstrates Jetti’s unmatched expertise in the science behind copper leaching.

Ren et al.

This process enables the recovery of previously trapped copper resources, thus significantly increasing the output and lifespan of existing copper production facilities. This way, copper extraction becomes substantially more efficient and reduces its environmental impact.

Jetti Resources’ method allows copper mines to use heap leaching on these ores, which causes around 40% fewer CO₂ emissions compared to traditional raw material extraction and uses only approximately 50% of the water. The technology is already being deployed to great success at industrial scale. Jetti Resources plans to push ahead with global expansion together with its partners.

Resources

• Zihe Ren, Chihwei Chao, Prashanth Krishnamoorthy, Edouard Asselin, David G. Dixon, Nelson Mora (2022) “The overlooked mechanism of chalcopyrite passivation,” Acta Materialia doi: 10.1016/j.actamat.2022.118111