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dc.contributor.advisorMishra, Brajendra
dc.contributor.authorStrauss, Mark Lawrence
dc.date.accessioned2016-06-21T22:55:24Z
dc.date.accessioned2022-02-03T12:57:08Z
dc.date.available2017-06-21T04:18:44Z
dc.date.available2022-02-03T12:57:08Z
dc.date.issued2016
dc.identifierT 8079
dc.identifier.urihttps://hdl.handle.net/11124/170305
dc.descriptionIncludes bibliographical references.
dc.description2016 Spring.
dc.description.abstractPhosphor dust was characterized to quantify the various mineralogical phases. QEMSCAN determined that more than 70% of the rare earth minerals are less than 10µm in size and the main gangue material, quartz, was primarily larger than 74µm. Beginning with a europium and yttrium-rich pregnant leach solution, the optimized conditions for oxalic acid precipitation were determined. Grade and recovery curves were developed using the conditions optimized by Stat-Ease 9.0.5. The results demonstrate that using ambient temperature and native pH were ideal for creating 99% pure yttrium and europium mixed oxides with more than 99% stage recovery.The selective reduction and precipitation of europium from mixed yttrium and europium powders was completed with more than 95% pure europium (II) sulfate with more than 80% recovery at lab scale. The oxidation-reduction potential was demonstrated versus time for the selective reduction of europium (III) to europium (II). A novel SEM image was discovered and can be used as a signature for europium (II) sulfate. Gibbs minimization was used to model the preparation, reduction, and precipitation portion of the experiments.A scoping study was conducted to analyze the economics of building a phosphor dust recycling facility beginning with pre-sieved, freight-on-board (FOB) waste lamp phosphor powder and ending with a salable 99% pure mixed yttrium and europium oxide product to a customer willing to purchase it for a 30% discount from China FOB rare earth prices. The process was economic using a 6 year REO price average (NPV $17.7 million) and 2 year REO price average (NPV $2.4 million), but is uneconomic at current REO prices. The break-even price for europium oxide is $420 per kg and $15.50 per kg for yttrium oxide.
dc.format.mediumborn digital
dc.format.mediummasters theses
dc.languageEnglish
dc.language.isoeng
dc.publisherColorado School of Mines. Arthur Lakes Library
dc.relation.ispartof2016 - Mines Theses & Dissertations
dc.rightsCopyright of the original work is retained by the author.
dc.subjecteuropium
dc.subjectmetallurgy
dc.subjectphosphor dust
dc.subjectrare earths
dc.subjectrecycling
dc.subjectyttrium
dc.titleRecovery of rare earth oxides from waste fluorescent lamps, The
dc.typeText
dc.contributor.committeememberTaylor, Patrick R.
dc.contributor.committeememberAnderson, Corby G.
dc.contributor.committeememberSpiller, D. Erik
dc.contributor.committeememberMartins, Gerard P.
dcterms.embargo.terms2017-06-21
dcterms.embargo.expires2017-06-21
thesis.degree.nameMaster of Science (M.S.)
thesis.degree.levelMasters
thesis.degree.disciplineMetallurgical and Materials Engineering
thesis.degree.grantorColorado School of Mines
dc.rights.accessEmbargo Expires: 06/21/2017


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