Strong microwave magnetic fields for more efficient plasmas
A team of researchers from Tohoku University and the Toyohashi University of Technology has developed a new method to create metallic plasmas from solid metals. Plasmas are hot gases composed of metal ions and electrons that are widely used in various industrial processes. This new method involves the application of a strong magnetic field to a solid metal in a microwave resonator. The researchers believe that their innovative process could significantly improve the efficiency of plasma techniques in many applications.
Traditional methods for generating plasmas require a strong electric field applied to gases or liquids, which can require vast amounts of energy. More recently, microwave radiation has been used to generate plasmas due to its ability to convert atoms into a form that can drive desired chemical processes more effectively.
The researchers have achieved a key advance in this area by applying a single-mode microwave generator to produce their metal plasmas. This creates more controlled and highly focused microwaves. Until now, the use of multi-mode microwave generators has resulted in a chaotic distribution of microwaves.
New and unconventional method
Jun Fukushima, a chemist involved in the research, explains that the team expects their new process to significantly improve the efficiency of plasma techniques in various applications and enhance profitability in the commercial arena. This new and unconventional method for utilizing plasmas is considered crucial for reducing the energy requirements for future materials science applications.
One of the significant challenges the team faced was stabilizing the initial plasmas for more than ten minutes. However, the researchers redesigned the equipment and eventually achieved much longer stability. The final and more innovative system contains a double quartz tube, with the solid material that is converted into the plasma sitting within the inner tube.
Potential applications in rare earth metal extraction
The researchers expect their technology to be especially useful for extracting pure rare earth metals from their ores. Rare earth metals, such as cerium, lanthanum, and neodymium, are becoming widely used in large-scale applications, including the manufacture of rechargeable batteries for electric vehicles. The team has already demonstrated using a plasma of calcium and magnesium to release scandium and vanadium atoms from their oxide ores.
Journal Information: Satoshi Fujii et al, Metal ion plasma generation under strong magnetic field in microwave resonator, AIP Advances (2023). DOI: 10.1063/5.0134071