Eliminating ammonia emissions during rare earth separation through control of equilibrium acidity in a HEH(EHP)-Cl system

Abstract

This paper investigates the development of a new environmentally friendly approach for rare earth separation. A technique for controlling equilibrium acidity in a HEH(EHP)-Cl system achieves ammonia-free emissions during rare earth separation while obtaining an organic phase with high rare earth loading. A simulated model of the proposed equilibrium acidity control technology is first studied in a HEH(EHP)-Cl system to determine the extraction equilibrium and mass balances for a counter current extraction system, so as to optimize the mass distribution in the multi-component system. Using these results, a pilot test separating Gd and Tb in a HEH(EHP)-Cl system is conducted using the proposed equilibrium acidity control technology, and without saponification, to verify the process and show that the method obtains ammonia-free emissions using an industrial separation process. © 2013 The Royal Society of Chemistry.