Nanohydrometallurgy with superparamagnetic nanoparticles for selective separation of lanthanum from a real spent catalyst

The development of new methodologies and sustainable processes is a priority in the field of chemical engineering and nanotechnology. In this study, via an easy route, the nanohydrometallurgy process was applied to recover La from a real spent catalyst. The synthesis of superparamagnetic iron nanoparticles (Si@FeNPs) with different precursors was evaluated. The average particle diameter value was smaller when using sulfate precursors. La acid leaching extracted 76% and required process adjustments. The nanohydrometallurgy process separated La from the Ni present in the leach solution with 6 cycles. Therefore, two processes were proposed. The first is obtaining a product with 97% of La and Al as a contaminant. The second with 99% La purity. Nanohydrometallurgy proved to be an innovative and sustainable process, with the recyclability of Si@FeNPs, obtaining La from a secondary source. In this way, this nanohydrometallurgy process meets the concepts of circular economy and encompasses sustainable development goals (SDGs) nine and twelve of the United Nations.

Graphical abstract