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Leon Prentice Leads “Supersonic” Advances in Magnesium Production |
By Lynne Robinson
Posted on: 11/23/2012 12:00:00 AM... Effectively deploying magnesium—the lightest of all structural metals—in the transportation industry could yield significant fuel and carbon reduction efficiencies. Ironically, these potential benefits are offset by the fact that traditional magnesium production methods are extremely energy-intensive and detrimental to the environment. Leon Prentice, senior research engineer, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Melbourne, Australia, is using the tools of “rocket science” to change that equation.
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(Click on photos to enlarge.) Prentice with the MagSonic laboratory-scale apparatus.
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A supersonic nozzle enables the MagSonic technology.
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High-purity magnesium crystals. (Photo courtesy of CSIRO.)
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Prentice and his work on MagSonic™—a technology that enables magnesium production by carbothermal reduction—earned the 2013 Vittorio de Nora Prize for Environmental Improvements in Metallurgical Industries. At laboratory scale, the MagSonic process indicates the potential to cut the energy consumption required for magnesium production by half and reduce its environmental impact by 85 percent. “I’m proud of the work that my team and I have put in over the last few years, and I think the environmental sustainability advantages of the MagSonic technology are evident. I’m hoping that those advantages can be realized in practice in the near future, as the technology is developed and scaled up to make a major impact in the industry,” Prentice said. “It’s also a profound honor to be selected for the prize, as I know many very able researchers and colleagues who are doing excellent work and making a difference in metallurgical industries.”
MagSonic involves heating magnesia with carbon to above 1700°C in an inert atmosphere to reduce the magnesium to a vapor and produce carbon monoxide. To prevent the magnesium from reverting back to magnesia, MagSonic uses a Laval nozzle—historically utilized in rocket engines for propulsion—to “shock quench” the gases. The gases are pulled through the nozzle at four to five times the speed of sound, causing them to cool in milliseconds and freezing the magnesium. The magnesium can then be separated from the carbon monoxide and recovered as a powder.
At the time Prentice joined the project in 2007, the team had successfully achieved supersonic quenching, but still faced several challenges. Of these, Prentice said, preventing the condensing magnesium and related impurities from forming a solid mass and blocking the nozzle was the most complex. That has since been resolved, with Prentice noting that the process can now operate indefinitely without experiencing a blockage. The team has also made great strides in recovering the magnesium powder. “We thought the particle size would be too small to effectively capture,” said Prentice. “Not only can we capture the powder, we’ve also worked out a good way of re-melting and purifying it.”
Prentice said that an aspect of the MagSonic project that he appreciates is “the inherent simplicity—almost elegance—of the carbothermal reaction, offset by its engineering challenges.” He notes that he is also motivated “to find sustainable solutions to more global issues.”
“I think process engineers, particularly those in research, are uniquely placed to make a significant difference in our world,” he said. “We need to address the fundamental issues that are becoming more and more apparent—energy, water, climate, sustainability, food, and so on. I spent a large part of my childhood growing up in Africa, and I’m passionate about technologies that can make a difference for everyone.”
MagSonic, Prentice believes, is one of those technologies. “If fully commercialized, the MagSonic technology can revolutionize global magnesium production, resulting in very significant environmental and energy efficiency gains throughout the value chain,” he said. “The environmental advantages would be enormous, not only in the primary production process, but also by increased uptake of magnesium into motor vehicles, aircraft, and anything else that benefits from its lightness.”
Prentice said that winning the de Nora Prize marks a significant step in MagSonic’s development by “encouraging researchers in CSIRO to continue doing great science that has profound real-world impact. I hope it raises the profile of what we do—in particular that we have the ability to pull together multi-disciplinary, specialized teams to work on challenging projects of national and global relevance.”
Editor’s Note: Prentice will deliver the 2013 Vittorio de Nora Prize Lecture at the TMS 2013 Annual Meeting and Exhibition, March 3 –7, in San Antonio, Texas. For details, go to the conference website.
Lynne Robinson is a news and feature writer for TMS.
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