Ra’ike: Wikimedia CC-GFDL
Makes Sensor—The UA’s Dominic Gervasio, left, and Hassan Elsentriecy in their lab.
Salt Solution—High-temperature salts clean up copper extraction.
UA Startup Tackles Galvanic Corrosion
Salt Research Applied to Copper Refining
The metal alloys used in pipes corrode faster when the temperature of the material that flows through them is higher.
Arizona has long been a leader in the copper mining industry, but traditional processes for extracting the metal from the ore release toxins into the environment through seepage, air pollution and, in the worst cases, tailings pond failures.
Industries like metal refining, smelting and solar energy move molten salts heated to upward of 1,500 degrees Fahrenheit, about the temperature of orange-hot molten rock, through systems of such pipes. Applications for molten materials are developing quickly, but progress is being slowed by the rapid corrosion of the metal pipes in these systems. This process, called galvanic corrosion, occurs because of the voltage differential between the pipe’s alloys and the molten material within. The bigger the difference in voltage between the two, the faster the corrosion. To solve this corrosion conundrum, UA College of Engineering professor Dominic Gervasio and principal research specialist Hassan Elsentriecy from the department of chemical and environmental engineering, in collaboration with Peiwen “Perry” Li from the department of aerospace and mechanical engineering, have invented a new breed of sensor – a reference electrode – designed to work in these ultrahigh-temperature environments. “We needed a reference electrode that worked in our molten salt processes, but none were available,” Gervasio said. “So we invented one that can be used in solar power, nuclear reactors, petroleum refining applications and others.” Funded by the Department of Energy and serial entrepreneur and co-inventor Abraham Jalbout, the team worked with Tech Launch Arizona, the UA office that commercializes the inventions stemming from University research, to patent the technology and bring it to market via a startup company, Caltrode. The company’s primary technology is a specialized electrode that sits inside pipes transporting molten materials and monitors the voltage differential between the pipes and their lava-hot contents. 12 ARIZONAENGINEER 39:1 spring 2016
Chemical and environmental engineering professor Dominic Gervasio and principal research specialist Hassan Elsentriecy have invented a toxin-free method using high-temperature molten salts to extract the metal from raw copper ore. The method was a byproduct of their work with Peiwen “Perry” Li (see adjacent Peiwen “Perry” Li story) on high-temperature molten salts. Funded in part by entrepreneur and co-inventor Abraham Jalbout, the team worked with Tech Launch Arizona to bring the technology to the market via a startup company, MetOxs Electrochemical. Current methods for extracting copper from ore involve chemical processes that produce mountains of waste mine tailings and lakes of waste water that accumulate toxins such as arsenic, cadmium and sulfuric acid. The refining method works by heating the ore using molten salts to temperatures exceeding 1,500 degrees Fahrenheit, which separates the copper from the ore. The technique is transferable to any mineral-extraction process. “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,” said Bob Sleeper, Tech Launch Arizona licensing manager for the College of Engineering. As a parallel benefit, the technology allows for the collection of surplus heat that can be used to power steam turbines and generators.