Aspiring’s pilot plant, which opened in February, is in an anonymous industrial estate east of the city. One corner of the main floor is dominated by a large stainless-steel tank, which is connected to a series of smaller tanks arranged in a stepped line. “Apart from our electrolysis system, the hardware is more typical of dairy plants,” says Colum Rice, Aspiring’s chief commercial officer. “The process is elegant but not massively complicated. Our inputs are rock, water, and renewable energy, and our products come with no CO~2~ emissions.”

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Danczyk explains that at the end of the extraction process, they’re left only with a salty brine. “This goes to an electrolyzer, which recycles and regenerates the acid we use for digestion and the base we use to separate the products. It’s a closed loop. We’re using the whole rock, and we’re processing it at low temperature and ambient pressure.”

This sounds great, but scaling electrolysis would require shedloads of renewable energy.