Non-thermal Extraction of Rare Earth Elements from Fluorescent Powder by Means of its Mechanochemical Treatment.

Abstract

Leaching of fluorescent powder containing rare earths using 1N HCl solution at room temperature was conducted to extract the rare earths, followed by dry grinding of the powder using a planetary ball mill. The dry mechanochemical treatment of the powder causes the structural change of the crystals in the powder into a disordered system. This mechanochemical treatment leads to easy extraction of the rare earths. Only 3 minutes of grinding enables us to extract Y and Eu at above 70-80 % yield. More than 80 % of the other rare earths can be extracted from the powder ground for 2-hours. The mechanochemical treatment to the fluorescent powder before leaching would be an effective operation to be able to extract the rare earths at high yield in room temperature leaching even by low concentration HCl solution.