ADVANCED MATERIALS & PROCESSES | NOVEMBER/DECEMBER 2025 6 METALS | POLYMERS | CERAMICS removing toxic metals from bauxite residue, or red mud, a hazardous by-product of aluminum production. The new technique involves a brief electrical pulse lasting under one minute along with a small amount of chlorine gas. If implemented on a larger scale, the team believes it could revolutionize global waste management and materials recovery. The process uses flash Joule heating (FJH), which rapidly heats materials with a short, highpower electrical pulse to vaporize harmful metals, leaving behind a residue rich in aluminum. The material can then be repurposed into durable ceramic tiles or bricks or put through the standard aluminum production process. Every year, millions of tons of red mud accumulate as toxic waste from aluminum production, which contains harmful metals. Disasters related to its storage have caused river contamination and flooding. The researchers aimed to explore whether this waste could be repurposed rather than merely contained. The FJH method works by REFRACTORY ALLOY RESISTS HIGH TEMPS Researchers at Karlsruhe Institute of Technology (KIT), Germany, developed a refractory alloy made of chromium, molybdenum, and silicon that is ductile at ambient temperature. With a melting temperature of 2000°C, it remains stable at high temperatures and is oxidation resistant. Refractory metals such as tungsten, molybdenum, and chromium whose melting points are around 2000°C can be the most resistant to high temperatures, but they are brittle at room temperature. Once in contact with oxygen, they cause failure within a short time at temperatures of 600-700°C. Due to these challenges, nickelbase superalloys have been used for decades in components exposed to air or combustion gases at high temperatures, such as gas turbines. However, the temperatures in which they can be used safely are in the range of 1100°C maximum. This limitation was the starting point for Professor Martin Heilmaier’s team from KIT’s Institute for Applied Materials. Within the “Materials Compounds from Composite Materials for Applications in Extreme Conditions” research group, the scientists succeeded in developing their new alloy. This is significant because resistance to oxidation and ductility cannot be predicted sufficiently to allow a targeted material design, despite great progress in computer-assisted materials development. “In a turbine, even a temperature increase of just 100°C can reduce fuel consumption by about five percent,” says Heilmaier. Stationary gas turbines in power plants could also be operated with lower CO emissions due to more robust materials. “To be able to use the alloy on an industrial level, many other development steps are necessary,” he added. “However, with our discovery in fundamental research, we have reached an important milestone.” kit.edu. NEW PROCESS TURNS RED MUD INTO CERAMICS Scientists at Rice University, Houston, developed a faster and cleaner method for recovering aluminum and Alloy production by means of arc melting in the material synthesis lab of the Institute for Applied Materials. Courtesy of Chiara Bellamoli/KIT. The FJH method can remove toxic metals from bauxite residue. Courtesy of Rice University. New research from Oak Ridge National Laboratory, Tenn., answers an old question: Do tiny pores in graphite affect nuclear reactor performance? No. The study confirms that small voids in graphite do not disturb the atomic vibrations that determine its interactions with neutrons, giving reactor developers greater confidence that graphite will perform its moderation duties as expected. ornl.gov. BRIEF
RkJQdWJsaXNoZXIy MTYyMzk3NQ==