Sustainable recovery of precious metals from end-of-life vehicles shredder residue by a novel hybrid ball-milling and nanoparticles enabled froth flotation process

It is hereby reported a simple, effective and sustainable method for the recovery of precious metals from end-of-life vehicle shredder residue and/or automobile shredder residue based on a hybrid ball-milling and microbubble froth flotation process. A ball-milling treatment of automobile shredder residue along a mixture of Fe/Ca/CaO nanoparticles had as main result the entrapment of precious metals and in subsidiary an improvement of the floatability of the various size fraction particles (1.0, 0.425, and 0.25 mm, respectively). Therefore, a separation of the settled fraction (poor in precious metals) and the floating fraction yielded a recovery of approximately 83–89% precious metals in the latter. Scanning electron microscopy-energy dispersive X-ray spectroscopy maps of gold (Au), silver (Ag), platinum (Pt), palladium (Pd), Iridium (Ir), and copper (Cu) confirmed that result.