A D V A N C E D M A T E R I A L S & P R O C E S S E S | M A R C H 2 0 2 3 2 2 which can be overcome by the special mixing unit. If the temperature is increased further to the target temperature of approximately 850°F, pyrolysis is complete. The end product is a powder. Recycling of rare earths. High-temperature processes are also used to return rare earths to the circular economy. When old lamps are recycled, approximately 1% to 3%mercurycontaining lamp powder remains, which is typically disposed of as hazardous waste. These lamps also contain rare earth minerals. However, due to its high toxicity, mercury must first be separated from the other metals before further recycling can proceed. This can be achieved in batch-operated, horizontal high-temperature dryers. In the first stage, the product is heated to approximately 400°F to remove any liquids, such as water or solvents. The dry product is then heated further until the mercury has completely evaporated. Values below 10 ppm are possible. The system is designed to be completely closed with neither the operator nor the environment exposed to mercury. TESTING NEW APPLICATIONS Potential new applications include thermal cleaning of metals and production of cathode and anode material, among others. Some companies such as BHS-Sonthofen offer an extensive range of testing options on flexible, mobile pilot machines. Depending on project requirements, BHS adjusts the system and selects additional modules for exhaust gas aftertreatment, for example. The dynamic process of contact drying offers an energy-efficient and high quality alternative to existing technologies found in the chemical and process industries, as well as in research and development. ~AM&P For more information: Jan Wankerl, technical sales manager, BHS-Sonthofen GmbH, An der Eisenschmelze 47, 87527 Sonthofen, Germany, +49 81.5293.9241, jan. wankerl@bhs-sonthofen.com, bhssonthofen.com. Expand your Heat Treating Knowledge with these Upcoming Courses Education asminternational.org/exploreeducation Practical Heat Treating | April 3–5 Vacuum Heat Treating | May 4–5 HT, Microstructures and Performance of Carbon and Alloy Steels | May 18–19 Basics of Heat Treating | June 12–14 Heat Treating, Furnaces and Equipment | June 15–16 Practical Induction of Heat Treating | July 18–20 HT, Microstructures and Performance of Carbon and Alloy Steels | August 21–22 Vacuum Heat Treating | September 7–9 Visit asminternational.org/exploreeducation to register for an upcoming course.
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