| Treatment of exhaust fluorescent lamps to recover yttrium: Experimental and process analyses. | |
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MedLine Citation:
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PMID: 21840197 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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The paper deals with recovery of yttrium from fluorescent powder coming from dismantling of spent fluorescent tubes. Metals are leached by using different acids (nitric, hydrochloric and sulphuric) and ammonia in different leaching tests. These tests show that ammonia is not suitable to recover yttrium, whereas HNO(3) produces toxic vapours. A full factorial design is carried out with HCl and H(2)SO(4) to evaluate the influence of operating factors. HCl and H(2)SO(4) leaching systems give similar results in terms of yttrium extraction yield, but the last one allows to reduce calcium extraction with subsequent advantage during recovery of yttrium compounds in the downstream. The greatest extraction of yttrium is obtained by 20% w/v S/L ratio, 4N H(2)SO(4) concentration and 90°C. Yttrium and calcium yields are nearly 85% and 5%, respectively. The analysis of variance shows that acid concentration alone and interaction between acid and pulp density have a significant positive effect on yttrium solubilization for both HCl and H(2)SO(4) medium. Two models are empirically developed to estimate yttrium and calcium concentration during leaching. Precipitation tests demonstrate that at least the stoichiometric amount of oxalic acid is necessary to recover yttrium efficiently and a pure yttrium oxalate n-hydrate can be produced (99% grade). The process is economically feasible if other components of the fluorescent lamps (glass, ferrous and non-ferrous scraps) are recovered after the equipment dismantling and valorized, besides the cost that is usually paid to recycling companies for collection, treatment or final disposal of such fluorescent powders. |
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Authors:
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Ida De Michelis; Francesco Ferella; Ennio Fioravante Varelli; Francesco Vegliò |
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Publication Detail:
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Type: JOURNAL ARTICLE Date: 2011-8-11 |
Journal Detail:
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Title: Waste management (New York, N.Y.) Volume: - ISSN: 1879-2456 ISO Abbreviation: - Publication Date: 2011 Aug |
Date Detail:
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Created Date: 2011-8-15 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 9884362 Medline TA: Waste Manag Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Copyright Information:
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Copyright © 2011 Elsevier Ltd. All rights reserved. |
Affiliation:
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University of L'Aquila, Department of Chemistry, Chemical Engineering and Materials - Ex-Optimes Loc., Campo di Pile, 67100 L'Aquila, Italy. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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