A single-step method enables the energy saving extreaction of Nickel with reduced CO2 emissions for batteries and stainless steel
The conventional production of nickel, such as here in Sorowako, Indonesia, generates 20 tons of CO2 per ton of nickel. However, there is equipment in the production facilities that can be used to produce nickel in an energy-efficient and nearly CO2-free process.
© SOPA Images / Sipa USA / picture alliance
To the point
- Challenging nickel demand: the demand for nickel is expected to double while conventional nickel production emits around 20 tons of CO2 per one ton of nickel
- Sustainable new process for nickel production: Researchers found a way to extract nickel from low-grade ores using hydrogen plasma instead of carbon. The one-step process is CO2-free and saves energy and time.
- Upscaling possible: For upscaling, implementing short arcs with high currents, integrating an external electromagnetic stirring device beneath the furnace, or employing gas injection, is needed, making sure that the unreduced melt continuously reaches the reaction interface.
To combat climate change and achieve a climate-neutral industry, carbon emissions must be drastically reduced. A key part of this transition is replacing carbon-based energy carriers with electricity, particularly in transport and industrial applications. However, this shift heavily depends on nickel, a critical material used in batteries and stainless steel. 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 have now 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. The Max Planck team now published their results in the journal Nature.
One single step to green nickel
Ubaid Manzoor using an electric arc furnace to reduce low-grade nickel ores with hydrogen plasma.
© Max-Planck-Institut für Nachhaltige Materialien GmbH
"If we continue producing nickel in the conventional way and use it for electrification, we are just shifting the problem rather than solving it", says Ubaid Manzoor, PhD researcher at the Max Planck Institute for Sustainable Materials. 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. This approach not only cuts CO2 emissions by 84 percent but is also up to 18 percent more energy-efficient when powered by renewable electricity and green hydrogen.
Traditionally, industry relies on high-grade ores, as extracting nickel from lower-grade ores is far more complex due to their chemically intricate composition. Unlike iron, which can be reduced in a single step by removing oxygen, nickel in low-grade ores is chemically bound within complex magnesium silicates or iron oxides. Conventional extraction involves multiple stages like calcination, smelting, reduction, and refining, which are energy-intensive and have a large carbon footprint. A major breakthrough of this method is its ability to process low-grade nickel ores (which account for 60 percent 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", says Isnaldi Souza Filho, group leader at the Max Planck Institute for Sustainable Materials.
Towards industrial application
This method not only reduces emissions and energy consumption, but also broadens the spectrum of usable nickel ores, making extraction more cost-effective and sustainable. 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", says Ubaid Manzoor. "In an upscaled system, it is crucial to ensure that unreduced melt continuously reaches the reaction interface." This can be achieved by implementing short arcs with high currents, integrating an external electromagnetic stirring device beneath the furnace, or employing gas injection. These are well-established industrial techniques, making integration into existing processes feasible.
Comparison of conventional nickel production and the newly developed green nickel method. While conventional production involves multiple stages from ore preparation to drying steps, the newly developed method relies solely on the reactions taking place during the hydrogen plasma smelting reduction (HPSR). On the right, the reduced nickel-iron alloy is visible inside the slag after 4 minutes of hydrogen plasma reduction.
© Max-Planck-Institut für Nachhaltige Materialien GmbH
The green nickel production route opens the door to a more sustainable electrification of the transport sector. 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.
Yasmin Ahmed Salem
