Magnetic nanohydrometallurgy: a nanotechnological approach to elemental sustainability

Abstract

Magnetic nanohydrometallurgy (MNHM), although yet in a very incipient stage, is opening new and exciting perspectives in conventional hydrometallurgy, thus aggregating nanotechnology to the mineral area. MNHM is based on the same principles of coordination chemistry successfully employed in modern extractive hydrometallurgy processes; however, it uses specially designed superparamagnetic nanoparticles for capturing, transporting, confining and processing metal ions with the aid of an external magnet. The working nanoparticles are completely recovered after the electrodeposition process, sustaining a cyclic process which can be automated, without using organic solvents and intensive chemical processing, as is the case of current extractive hydrometallurgy and electrowinning technology. At the laboratory scale, the entire procedure can be performed in the same reactor, fulfilling, in addition to the processing and recovery facilities, the most important requisites of green chemistry.