Recovery of Rare Earths from Waste Catalyst

A hydrometallurgical process is developed to recover rare earth metals from waste catalyst. The waste catalyst contains 2% ~ 5% rare earth elements,mainly lanthanum and cerium. The experimental results showed that rare earths could be dissolved by acid leaching. The optimum leaching temperature,ratio of solid to liquid,acidity and reaction time for waste catalyst were 30 °C,1: 8,4. 8 mol / L,and 2 h,respectively,and the leaching rate of rare earths reached 98. 26%. Rare earths were recovered by selective precipitation with oxalic acid at pH about 2 after leaching. The recovery rate of rare earths from waste catalyst reached 95% in the whole leaching and separation process. The residual Al3 +in solution was recovered.