By 2040, the demand for nickel is expected to double due to the increasing electrification of the infrastructures and transport systems. Yet, producing one ton of nickel currently emits around 20 tons of CO2, raising concerns about shifting the environmental burden from transportation to metallurgy. Researchers at the Max Planck Institute for Sustainable Materials (MPI-SusMat) have developed a carbon-free, energy-saving method for nickel extraction. Their approach also enables the use of low-grade nickel ores, which have been overlooked due to the complexity of conventional extraction processes.
“If we continue producing nickel in the conventional way and use it for electrification, we are just shifting the problem rather than solving it,” explained Ubaid Manzoor, PhD researcher at MPI-SusMat and first author of the publication. Manzoor and his colleagues have developed a new method to extract nickel from ores in a single step, using hydrogen plasma instead of carbon-based processes. The new process reduces CO2 emissions by 84% and is up to 18% more energy-efficient when renewable electricity and green hydrogen are used, as the repeated heating and cooling of the ore, which is common in conventional processes, is avoided.
A major breakthrough of this method is its ability to process low-grade nickel ores (which account for 60% of total nickel reserves) in a single reactor furnace, where smelting, reduction, and refining occur simultaneously, producing a refined ferronickel alloy directly.
“By using hydrogen plasma and controlling the thermodynamic processes inside the electric arc furnace, we are able to break down the complex structure of the minerals in low-grade nickel ores into simpler ionic species, even without using catalysts,” explained Professor Isnaldi Souza Filho, head of the group Sustainable Synthesis of Materials at MPI-SusMat and corresponding author of the publication.
The next step for the Max Planck team is scaling up the process for industrial applications. “The reduction of nickel ores into simpler ionic species occurs only at the reaction interface, not throughout the entire melt. In an upscaled system, it is crucial to ensure that unreduced melt continuously reaches the reaction interface,” explained Manzoor. “This can be achieved by implementing short arcs with high currents, integrating an external electromagnetic stirring device beneath the furnace, or employing gas injection.”
The reduced nickel alloy can be used directly in stainless steel production and, with additional refinement, as a material for battery electrodes. Additionally, the slag produced during the reduction process can serve as a valuable resource for the construction industry, including brick and cement production. The same process can also be applied for cobalt, which is used in electric vehicles and energy storage systems.
The research was funded by an Advanced Grant of the European Research Council.
