Nickel production is notoriously dirty — here’s how to make it greener

Researchers have developed a process for refining nickel that they say could dramatically cut its carbon footprint, which is currently equivalent to the total emissions of a small country.

Implementing the process on an industrial scale would present some engineering challenges, but the experiment, described in Nature on 30 April¹, is a first demonstration of principle. “What we did here is to prove that the science works,” says co-author Ubaid Manzoor, a metallurgical engineer at the Max Planck Institute for Sustainable Materials in Düsseldorf, Germany.

Nickel is a key ingredient in stainless steel, and its use in lithium-ion batteries is predicted to lead to a doubling in global nickel demand by 2040. But it is also one of the dirtiest metals to process. “Primary production of nickel is highly carbon-intensive,” says Manzoor. On average, refining one ton of nickel ore produces around 20 tons of carbon dioxide (see ‘Emissions from extraction’).

That carbon intensity could grow even higher as more nickel is extracted from laterites, a type of ore that is currently underutilised. That process can release more than 40 tons of carbon dioxide per ton of nickel, in part because it uses carbon-rich coke — a material usually derived from coal — to remove oxygen from the rock via a chemical reduction reaction.

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