Extraction of rare earth elements from Abu–Tartour wet process phosphoric acid using synthesized salicylaldehyde azine

Abstract

BackgroundTotal rare earth elements (REEs) are often associated with uranium and thorium. In order to satisfy application for many different industries, REEs should be separated from uranium and other elements. One way to achieve an applicable separation scheme is to employ an extractant that will economically and selectively bind to REEs in the presence of potential interfering ions. ObjectiveThis work was designed to selectively recover REEs from the Abu-Tartour phosphoric acid solution using synthesized salicylaldehyde azine (SAA). ResultsThe operating extraction and stripping conditions of REEs extraction from phosphoric acid have been experimentally optimized. From the acid and extractant effects, 0.024 M SAA was suitable for the separation of REEs at 30% acid, which is similar to Abu-Tartour wet process phosphoric acid solutions (WPPA). The extraction isotherm predicts the separation of REEs at an aqueous-to-organic (A/O) phase ratio of 1/2 in three stages using 0.024 M SAA. From the stripped liquor using 2 M HCl, the stripped (REEs) were precipitated as rare earth oxalate. The extraction studies showed the best fit with the first order rate equation.