|About this Abstract
||Part C-3: Processing of Critical Metals
||Alternatives to 2-Ethylhexyl Phosphonic Acid, Mono-2-Ethylhexyl Ester for the Separation of Rare Earths
||James Quinn, Karin Soldenhoff, Geoffrey Stevens
|On-Site Speaker (Planned)
Solvent extraction technology using EHEHPA remains the backbone for industrial separations of rare earth elements. This process has some shortcomings, including a large plant footprint and high acid requirement for stripping of the heavy rare earths.
In this work, we examine a number of alternative mixed solvent extraction systems:
i) Mixtures of organo phosphonic and phosphinic acids such as EHEHPA/Cyanex 272 or Cyanex 572;
ii) Ionic liquid mixtures of EHEHPA with quaternary ammonium chloride (Aliquat 336); and
iii) Mixtures of carboxylic acids for yttrium/lanthanide separations.
We discuss and compare the efficacy of these systems with reference to the Nd/Sm separation, which is of industrial significance. Based on the extraction chemistry and the use of modelling tools to define the counter-current solvent extraction circuit, we present a techno-economic analysis of a separation plant and discuss the impact of various solvent systems on the CAPEX and OPEX.
||Planned: At-meeting proceedings