University of Arizona (UA) engineers have invented a toxin-free method, using high-temperature molten salts, to extract copper from raw ore. Separately, they developed new ways to utilize these same molten salts to recover and store the vast amounts of heat energy created in metal refining and smelting production. Together, the complementary inventions represent an opportunity to make big impacts in both mining and energy storage.

Current methods for extracting copper from ore involve chemical processes that produce huge mountains of waste mine tailings and lake-size wastewater collections, accumulating high levels of toxins such as arsenic, cadmium and sulfuric acid. However, the refining method developed by University of Arizona College of Engineering professor Dominic Gervasio and principal research specialist Hassan Elsentriecy, from the Department of Chemical and Environmental Engineering, works by heating the ore using molten salts to temperatures exceeding 1,500 degrees Fahrenheit so that the copper is separated for easy collection.

According to the researchers, the technique is transferrable to any mineral extraction process.

The ore is heated to more than 1,500 degrees Fahrenheit to separate the copper for collection. Image credit: USGS."What makes this truly unique is use of a very specific salt formula that has the ability to strip the copper from the ore without the use of water and dangerous chemicals," says Bob Sleeper, Tech Launch Arizona licensing manager for the College of Engineering.

As a parallel benefit, the technology also allows for the collection of surplus heat using it to power steam turbines and generators. The process is similar to—but much hotter than—that used for refining aluminum ore. Prior to this team’s research, such processing was not possible.

Funded in part by entrepreneur and co-inventor Abraham Jalbout, the team worked with Tech Launch Arizona, the UA office that commercializes inventions stemming from university research, to bring the technologies to market via startup company MetOxs Electrochemical. MetOxs CEO, Jalbout, is currently in discussions with multiple companies to scale up the process.

"Given what’s currently out there and what they’re bringing to the market, these technologies could really shift the paradigm with cleaner, more efficient methods for both mining and energy storage," Sleeper says.