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 degrees 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 degrees 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.

Automated summary

Waste cathode ray tubes (CRT) have the potential to recycle rare earth resources through an efficient recycling process. This study found that removing zinc from a CRT during microwave roasting can affect the mineral phases of rare earths. By adjusting parameters such as acid medium, concentration, temperature, and time, high leaching efficiency can be achieved, leading to the production of high-purity (Y,Eu)2(C2O4)3 salt.