Selective Extraction of Red Phosphor (Y2O3:Eu3+) Constituents from Waste Fluorescent Lamps Phosphor Using Acid Leaching

Abstract

Modern fluorescent lamp phosphor powder contains tricolor phosphor. This tricolor phosphor consists of three different types of rare earth phosphors: red (YOX), green (CMAT/LAP) and blue (BAM); mixed in varying proportions. The exact separation of these three rare earth phosphors is essential in order to precisely recover the contained rare earth elements from waste lamps phosphor. In this present work, we reported an efficient methodology for the separation of these three tricolor phosphors and the selective extraction of predominantly presented red phosphor (YOX) constituents using acid leaching. The waste phosphor powder was leached with different acids: both organic and inorganic type. The 3 M H2SO4 leaching was found to be most suitable for the selective extraction of red phosphor constituents, i.e. Y and Eu. The recovered phosphor powder was analyzed with SEM/EDS and XRD analysis. The obtained XRD pattern was refined using Rietveld refinement method for the quantification of phases present. Recovered red phosphor powder contained three main crystalline phases Y2O3, Eu2O3 and Y2OS2. KEYWORDS: Waste Lamp Phosphor; Tricolor Phosphor; Rare Earth Elements; Acid Leaching