Browsing by Author "Forte, Federica"
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Item Enhancing rare-earth recovery from lamp phosphor waste(2019-08) Yurramendi, Lourdes; Gijsemans, Lukas; Forte, Federica; Aldana, Jose Luis; del Río, Carmen; Binnemans, Koen; VALORIZACIÓN DE RESIDUOSIn the present work rare-earth recovery was performed from a residue of a hydrometallurgical process based on sulphuric acid leaching of lamp phosphor waste by which the red phosphor Y2O3:Eu3+ was removed for further recovery. The undissolved residue is rich in lanthanum, cerium and the valuable terbium, present as phosphates and aluminates in the green and blue phosphors. The process here proposed is based on an integrated pyro-hydrometallurgical approach involving a thermal treatment (roasting in the presence of sodium carbonate) aimed at converting rare-earth phosphates into oxides, which can be more easily leached by mineral acids (HCl and H2SO4) in a further leaching step. Rare-earth recovery from the leachate was then performed by solvent extraction with the extractant di-(2-ethylhexyl)phosphoric acid, D2EHPA, followed by precipitation with oxalic acid and calcination. 82% Ce, 75% La and 82% Tb were recovered as mixed La2O3 + CeO2 oxide (99% purity) and Tb4O7 (64% purity).Item Integrated process for the recovery of yttrium and europium from CRT phosphor waste(2019) Forte, Federica; Yurramendi, Lourdes; Aldana, José Luis; Onghena, Bieke; Binnemans, Koen; VALORIZACIÓN DE RESIDUOSAn integrated process flow sheet for the recovery of yttrium and europium from waste cathode-ray tube (CRT) phosphors was developed. This flow sheet is based on a sequence of roasting, leaching with organic acids and precipitation steps. Zinc was efficiently removed from the roasted CRT phosphors by leaching with acetic acid, giving access to the rare earth content. Yttrium and europium were quantitatively leached from the residue by a 1 mol L−1 methanesulphonic acid (MSA) solution. Precipitation with oxalic acid gave a mixed Y/Eu oxalate of high purity (>99 wt%). Co-precipitation of zinc was less than 2 wt%.