Selective Extraction of Y and Eu by Non-thermal Acid Leaching of Fluorescent Powder Activated by Mechanochemical Treatment using a Planetary Mill

摘要

Fluorescent powder was subjected tomechanochemical (MC) treatment using a planetary mill tocontrol its structural change followed by selective leaching of Yand Eu with 1N HCl solution at room temperature. The crystalstructure of the fluorescent powder tends to be transferred intodisordered state by the MC treatment. It is possible to controlthe crystal disordered state by choosing the MC condition suchas media size and rotational speed of the mill. The optimumcondition gives us to improve the yield of Y and Eu, depressingthe yield of La, Ce and Tb in the acid leaching. In the presentexperiment using 15 mm ball size, the preferable MC treatmentwould be conducted within about 20 minutes at 400rpm in mill rotational speed.