Recycling of Yttrium and Europium from Microwave-Roasted Waste Cathode Ray Tube Phosphor Powder

Waste cathode ray tubes (CRT) containing a high quantity of yttrium and europium have great potential for the resource circulation of rare earths through an efficient recycling process. This study examined how the removal of zinc from a CRT that had been microwave-roasted at various temperatures (600–800°C) affected the various mineral phases of rare earths. The parameters like acid medium, concentration, temperature, and time were varied to yield about 99% leaching efficiency using 2.0 mol/L HCl at 5% pulp density for 60 min of leaching performed at 90°C. The apparent activation energy values (Ea(Y), 22.1 kJ/mol, and Ea(Eu), 16.7 kJ/mol) show that the leaching follows an intermediate-controlled mechanism by following the logarithmic rate law. Finally, the mixed oxalate precipitation at the stoichiometric ratio of REE3+:C2O42– = 1:1.5 gave high-purity (Y,Eu)2(C2O4)3 salt.