Chemical Process Produces Critical Battery Metals with No Waste

Summary

Olivine is a rather unassuming rock. Olive brown to yellow green in color, this hard yet brittle mineral is thought to be the most abundant in Earth’s upper mantle. Chemically, olivine is magnesium iron silicate, though it contains other elements too. Economically, it’s close to worthless. Its limited industrial utility stretches to gemstones, metalworking, ceramics, and occasionally, as a gravel for road construction. At some mining sites, olivine is a waste product, stored in piles on the surface.It’s certainly not an obvious choice as a source for battery materials.But that’s exactly how it’s viewed by a group of New Zealand engineers. Christchurch-based Aspiring Materials has developed a patented chemical process that produces multiple valuable minerals from olivine, leaving no harmful waste behind. Perhaps most interesting to the energy sector is the rarest of its products—hard-to-source nickel-manganese-cobalt hydroxide that is increasingly required for lithium-ion battery production.Sustainable Mineral Extraction ProcessAspiring’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 CO2 emissions.”The rock is olivine “flour”; a fine, green-gray dust that is an unwanted by-product from refractory sand production. This is carried by screw conveyer into the largest tank, where it is combined with sulfuric acid. This acid-leaching step “transforms it into kind of an elemental soup,” says Megan Danczyk, lead chemical engineer at Aspiring. From there, it passes down the reaction chain vessels, where through t...