Mechanochemistry

Green and Sustainable Rare Earth Element Recycling and Reuse from End-of-Life Permanent Magnets

“…The use of this method opens new avenues in preparative chemistry, including both organic and inorganic synthesis. Numerous authors have investigated the compliance of the method with the established Principles of Green Chemistry and Engineering, revealing the benign-by-design nature of mechanochemistry [105,110,111]. Thus, the method is capable of providing advanced materials with unique characteristics and properties, while being environmentally friendly and respecting all the twelve green chemistry principles.…”

“…Thus, mechanochemical activation can be applied both as a separate or simultaneous milling and leaching technique. Separate mechanical treatment (activation) of REE-containing wastes was reported to improve the leaching process with an additional treatment under milder conditions, dramatically decreasing treatment temperature and time, as well as the need for the use of aggressive, toxic, and corrosive chemicals [107,111,112]. Even though the term mechanochemistry or mechanochemical activation is not exactly mentioned, a large number of investigations have been focused on the impact of mechanical pretreatment on NdFeB magnet recycling, such as shredding, cutting, crushing, grinding, and milling [111][112][113].…”

“…The waste processing described in the presented examples is currently on a laboratory scale, but there are big expectations that they will be applied in the field of industries that emit the respective waste materials. Mechanochemistry offers a significant potential to replace classical extractive metallurgy due to numerous advantages such as high efficiency (higher leaching yields and selectivity), a significantly lower environmental footprint (solvent-free processing, dramatic reduction in chemical consumption, very low toxic emissions and waste), and a decrease in the number of technological stages, with the possibility for one-pot and one-step waste processing [104,111,112]. Mechanochemical treatment of the magnets together with the appropriate additives leads to a sufficient release of the REEs, reducing the dissolution time and increasing leaching efficiency and selectivity.…”

Review on Generation and Characterization of Copper Particles and Copper Composites Prepared by Mechanical Milling on a Lab-Scale

“…Although their milling mechanisms are different, the parameters that can be altered to determine the particle size distribution of the obtained powder are usually the same. Such parameters include the ball-to-powder ratio (BPR), the diameter of the milling balls, the materials, and the shape of the milling media, as well as milling speeds, milling environments, the size of the milling media, the milling atmosphere, and the temperature [32][33][34]. The main components of the mill are the milling chamber and the grinding media (which can be milling balls or a vibratory disc, for example).…”