Simultaneous separation of rare earths and valuable actinoid element from wet process phosphoric acid using N-propylpropan-1-amine extractant

Abstract

Phosphate rock is the main source for production of phosphoric acid, which in most cases is associated with rare earth elements (REEs) and valuable actinoid element (U) that eventually enter and build up in the soil and could lead to environmental harm. So, their separation is the crucial task to purify the wet process phosphoric acid (WPPA). The extractant N-Propylpropan-1-amine was used for the first time in the extraction and separation of U and REEs from WPPA. The REEs have also been selectively stripped from U. A traditional log DM-log [Extractant] analysis shows that the Extractant has removed U and REEs as a complex of 2:1 (extractant: metal ion) ratio. The extraction of U (95.3%) and REEs (98.7%) was achieved using 1 M N-Propylpropan-1-amine in kerosene utilizing an aqueous-organic-phase ratio of one at room temperature for about 7 min. The selectivity or separation factor (SF) REEs /M > 74 and SF of U/M > 35 was obtained for all interfering metal ions examined. Additionally, over 98.8% REEs were stripped selectively from loaded N-Propylpropan-1-amine using 6.0 M HCl in three stages. The thermodynamic analysis demonstrated that U and REEs extraction by N-Propylpropan-1-amine is an exothermic process. Finally, phosphoric acid produced from Abu-Tartour phosphate rock was treated with optimum parameters of solvent extraction for U and REEs separation.