Australian plants extracting high-value metals from mining wastes

Increasingly scarce metals are being recovered from mining waste by University of Queensland researchers, who are making the most of native plants' metal-absorbing nature.

Phytomining involves harvesting metals from the living tissue of a group of plants known as hyperaccumulators, which retain metals in high concentrations after absorbing them through their roots.

UQ's Sustainable Minerals Institute (SMI) researcher Dr. Philip Nkrumah has been developing the phytomining technology at the Centre for Mined Land Rehabilitation. "Australia is one of the world's leading mineral resources nations with a number of mines around the country generating large quantities of processed mining wastes," he said. "These wastes, often stored in tailings facilities, contain valuable metals including cobalt, and represent some of the largest untapped resources globally."

"Cobalt consumption is projected to rise by between eight and ten percent annually but supplies are likely to be limited by 2050, so the industry needs to identify additional sources," Dr. Nkrumah said.

"Phytomining is an innovative solution because it complements the global supply chain for critical minerals like cobalt while promoting the circular economy by utilising mining waste. "Some species of plants can contain up to one percent of cobalt or four percent of nickel in their shoots, translating to more than 25 percent metal in their ash which is dubbed 'bio-ore.'"