Mining faculty draw out copper with $1.7M DOE award

Copper conducts electrical currents in renewable energy technologies, smartphones and electric vehicles, but the critical mineral is difficult to process.

Sehliselo “Selo” Ndlovu, professor of extractive metallurgy and hydrometallurgy in the School of Mining Engineering and Mineral Resources, is developing a low-cost chemical solution to this challenge. Her research team – made up of faculty from the University of Arizona College of Engineering and Penn State, along with support from mining company Freeport-McMoRan and chemical company BASF – won $1.7 million from the U.S. Department of Energy’s Critical Materials Innovation Hub to improve copper recovery from low-grade sulfide ores. 

Advanced processing methods matter more than ever as mining companies turn to unyielding resources to meet growing demand.

“Most of the copper deposits that are being developed today are very low grade and increasingly difficult to process economically,” Ndlovu said. “Mining companies are looking for technologies that can increase copper recovery.”

Breaking stubborn bonds

Copper ores typically contain sulfide minerals such as chalcopyrite, which trap copper tightly within their crystal structure. That structure resists conventional leaching, a process that dissolves copper from ore using chemical solutions.

Ndlovu's team is developing a hydrometallurgical system that improves copper leaching. The multistep process uses water-based chemical solutions to extract valuable metals from minerals, offering a more economical option for processing lower-grade ores.

Their approach combines nanobubbles, surfactants and reactive oxygen species to break down copper sulfides and speed recovery. Nanobubbles improve oxygen transfer during the initial leaching process, and surfactants help the bubbles persist longer. Reactive oxygen species then accelerate the chemical reactions that release copper from the mineral structure.

Researchers expect the process to increase copper recovery by up to 30% compared with conventional leaching systems. A small increase could have significant implications for copper producers, Ndlovu said.

“Even 10% is very significant for this type of ore,” she said. “Thirty percent would really be a game changer for mining companies.”

Ready for real-world operations

Once refined, the process will work with existing copper extraction infrastructure – a crucial factor for adoption, since mining companies often hesitate to invest in unfamiliar systems.

“We knew that if we get this project to work, it should be as minimally disruptive to existing flowsheets or operations as possible,” Ndlovu said.

The collaborative team includes SMEMR associate professors Isabel Barton and Jinhong Zhang, Freeport-McMoRan Copper and Gold Chair in Mineral Processing, along with Penn State assistant professors of energy and mineral engineering Thandazile Moyo and Olumide Ogunmodimu.

Together, they will test material from multiple copper deposits. Ores can behave differently even when they contain the same copper minerals due to composition, texture and geological history.

Demonstrating the technology works across a range of ore sites will speed industry adoption. Success will lay the groundwork for pilot-scale testing at a mine site.

Freeport-McMoRan has agreed to supply samples and advise the team on practical approaches to mine implementation. BASF will evaluate surfactants and provide additional industry guidance.

Arizona advantage

Arizona’s position as the nation’s leading copper-producing state helped draw Ndlovu to the U of A in 2024.

“The support that we get from the copper mining industry here is massive,” she said. “The University of Arizona has a tremendous advantage because of its location and its strong relationships with industry.”

SMEMR postdoctoral student Sefiu Adewuyi agreed, adding, “Working on a project of this magnitude will strengthen my expertise in emerging extraction technologies and position me to contribute to the development of innovative solutions with scientific and industrial impact.”

The process could also apply beyond freshly mined copper ore. Researchers like Isabel Barton will investigate its potential for recovering copper from legacy tailings and other low-grade materials.

For Ndlovu, the project marks another step toward helping the mining industry make better use of challenging mineral resources.

“I try to have a vision for the future in terms of minerals,” she said. “Where is the world going? What does it look like for future resources? What technologies do we need for those types of resources?”