Improved rare earth elements recovery from fluorescent lamp wastes applying supported liquid membranes to the leaching solutions

Abstract

Due to the continuously growing demand of rare earths in advanced technologies, end-of-life fluorescent lamps may become feasible rare earth elements (REEs) raw materials, reducing thus their supply risk. Considering acid leaching as the most common method in the metal recover from an end-of-life product real scratch resulting from the fluorescent lamps, this paper proposes an improvement of the REEs recovery from these wastes adding a supported liquid membrane (SLM) step to minimize the loss of these metals in the first leaching (L1). HNO3 or HCl are the most appropriate acid agents in the L1 stage considering the balance between the Ca (II) impurity removal and the REEs losses minimization. These REEs lost can be entirely recovered from the L1 leachate by flat sheet supported liquid membranes (FSSLM) using Cyanex 923 as carrier and Na2EDTA as the receiving phase. REEs, especially Y and Eu, have been recovered in quantitative yields using a L1–FSSLM–L2 process.