Recovery of Y and Eu from waste CRT phosphor using closed-vessel microwave leaching

Abstract

Abstract Yttrium (Y) and europium (Eu) are critical rare earth elements (REEs) due to their high supply risk and importance for clean energy technologies. Their presence in electronic waste (e-waste) provides great potential of recovery and reuse. This study focused on recovery process of Y and Eu from waste cathode ray tube (CRT) phosphor using closed-vessel microwave leaching, followed by precipitation by oxalic acid and calcination. The effects of acid concentration and energy efficiency of closed-vessel microwave leaching were investigated. Leaching efficiency of Y and Eu was 86.67% and 100%, respectively, at the optimum operation conditions (10\xa0g/L of solid concentration, 2\xa0mol·L−1 of H2SO4 solution, 125\xa0°C, 30\xa0min of leaching time). When comparing with conventional heating process, closed-vessel microwave leaching process proved to be rapid, effective and efficient for Y and Eu recovery from waste CRT phosphor. Oxalic acid precipitation and calcination recovered 96.9\xa0±\xa00.26% of Y and 86.6\xa0±\xa00.76% of Eu as the crystallized product of (Y0.95Eu0.05)2O3.