|About this Abstract
||2021 TMS Annual Meeting & Exhibition
||Rare Metal Extraction & Processing
||Supercritical Extraction of Neodymium from NdFeB Magnet Using Organophosphorus Ligands
||Nattanai Kunanusont, Jiakai Zhang , Kimberly Watada , Yusuke Shimoyama , Gisele Azimi
|On-Site Speaker (Planned)
Supercritical fluid extraction is a promising green technology for urban mining of rare earth elements. To dissolve a metal in non-polar supercritical carbon dioxide (sc-CO2), it must be bonded with a combination of negative and neutral ligands, called chelating agents. Here, we investigate the effect of organophosphorus reagents on the extraction of neodymium from a neodymium-iron-boron magnet in sc-CO2. We use COSMO-vacancy model to predict the solubility of triethyl phosphate (TEP), tri-n-butyl phosphate (TBP), tributyl phosphine oxide (TBPO), and trioctyl phosphine oxide (TOPO) in sc-CO2 and show a TEP>TBPO~TBP>TOPO trend. We examine the stoichiometry of neodymium-ligand complexes using UV-Vis spectroscopy, showing a 1:1 Nd–TEP, 1:3 Nd–TBP, 1:4 Nd-TBPO, and 1:5 Nd–TOPO complex chemistry. Supercritical fluid extractions show TEP results in highest neodymium extractions followed by TBP, TBPO, and TOPO, because of the increase in coordination number that result in larger micellar assemblies with lower solubility in sc-CO2.
||Recycling and Secondary Recovery, Extraction and Processing, Other