Hydrogen plasma offers sustainable nickel production

From the stainless steel in wind turbines to electric vehicle batteries, nickel is playing a key role in the clean energy transition. Yet the industrial processes that make this important metal are energy intensive and emit huge amounts of climate-changing carbon dioxide.

To curb this environmental toll, researchers led by Isnaldi R. Souza Filho at the Max Planck Institute for Sustainable Materials have developed a more sustainable method that uses hydrogen plasma to extract nickel from low-grade ores. If it were powered by renewable electricity, this approach could reduce the CO₂ emissions of nickel extraction by up to 84% and energy consumption by about 18% compared with conventional techniques (Nature 2025, DOI: 10.1038/s41586-025-08901-7).

Global nickel production is expected to double by 2040, to roughly 6 million metric tons (t) per year—a jump driven largely by the booming battery market. That demand will increasingly need to be met by low-grade ores called laterites, which typically contain less than 1.5% nickel by weight. Because this nickel tends to be locked in complex magnesium silicates and iron oxides, it is challenging to extract.

Some laterites are processed by hydrometallurgical techniques that use heat, pressure, and copious quantities of sulfuric acid. Others are hammered by pyrometallurgical methods that reach 1600 °C and use the carbon-based fuel coke as a reducing agent, emitting about 20 t of CO₂ for every metric ton of nickel recovered. Both routes involve multiple stages, and producing a metric ton of nickel requires roughly 10 times as much energy as making the same amount of steel. Even then, the nickel products—including an iron-nickel alloy called ferronickel—often contain impurities such as phosphorus and silicon, necessitating further refining.

The new process saves energy by extracting and purifying nickel in a single step. As a proof of principle, the researchers put 10 g of low-grade ore pellets in an electric arc furnace with a mixture of hydrogen and argon. Then they applied a powerful electric current that melted the ore and created a hydrogen plasma containing a soup of atoms, ions, and electrons. The plasma reduced the ore’s nickel and iron ions to produce ferronickel, along with a residual slag of waste materials. This process is similar to one unveiled by Souza Filho’s team last year that the researchers used to extract iron from red mud, a toxic by-product of aluminum production.

“The reaction is really fast, between 2–4 min—that's really good,” says the Massachusetts Institute of Technology’s Amilton Barbosa Botelho Junior, a chemical engineer who has previously worked on extracting nickel from low-grade ores but was not involved in the research.

The method teased out 74–78% of the ores’ nickel, a little less than conventional techniques. Crucially, though, the ferronickel product was about 20–40% nickel—similar to existing routes. It also contained almost no impurities, which means it could be used directly in the stainless steel industry without further refining, says Ubaid Manzoor, a PhD student in Souza Filho’s group who led the experimental work.

The team is planning to build a larger-scale reactor, and one of the main challenges will be to keep the molten ore moving: the reaction occurs only at the interface of the plasma arc and unreduced metal oxides. “We have to keep a fresh supply of molten oxide at this interface,” Manzoor says. “If it’s stagnant, the reaction stops.”

Botelho Junior says it’s a promising technique but cautions that its environmental benefits depend on the use of green hydrogen. That’s hydrogen produced by electrolyzing water with renewable electricity, which is much more expensive than carbon-based reducing agents like coke. “When we talk about sustainability, we have to think about economic feasibility as well,” Botelho Junior says.

Nevertheless, Souza Filho’s team estimates that by avoiding refining steps and saving energy, its plasma process could be cost-competitive even when it uses green hydrogen.