Leaching of Rare Earth Metals from Phosphor Coating of Waste Fluorescent Lamps
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Phosphors made from compounds of rare earth metals (REMs) are very efficient. This material needs to be recycled for recovery of REMs after the fluorescent lamps (FLs) reach end of life. This work focuses on the leaching studies of REMs from phosphor. The phosphor was recovered from the spent linear FLs by end cut-push method. After detailed characterization of phosphor, effects of parameters viz. leachant, concentration, temperature, and pulp density were studied to determine the optimum leaching conditions. By using 9% (v/v) H2SO4, 98.6% (w/w) yttrium and 96.2% (w/w) europium could be leached out from phosphor at temperature, 70 °C, time, 4 h, and pulp density, 10% (w/v). The residue generated was treated with 54% (v/v) HCl to leach out 98.9% (w/w) lanthanum, 98.2% (w/w) cerium and 96.5% (w/w) terbium at temperature, 90 °C, time, 2 h, and pulp density, 10% (w/v). Kinetic studies of leaching reactions were also carried out.
KeywordsLeaching Rare earth metals Phosphor Waste recycling Fluorescent lamps
Infrastructure of the Hydro and Electrometallurgy Department of CSIR-IMMT, CSC0101 (MULTIFUN) and Polymetallic Nodules Programme (MoES, New Delhi) is gratefully acknowledged. The authors are thankful to Dr S.K. Biswal and Mr. S.K Jena, CSIR-IMMT, for their support in characterization of REMs by ICP-OES. J. Samantray is thanked for her help with alkali digestion of phosphor and residue samples.
- 1.Gupta C K, and Krishnamurthy N, Extractive Metallurgy of Rare Earths, 2nd edn, CRC Press, Boca Raton (2016).Google Scholar
- 2.Bauer D, Diamond D, Li J, Sandalow D, Telleen P, and Wanner B, Critical Materials Strategy, a report by US department of energy. URL https://www.energy.gov/sites/prod/files/DOE_CMS2011_FINAL_Full.pdf (2011) (accessed 12.11.18).
- 3.Humphries M, Rare Earth Elements: The Global Supply Chain, (2013).Google Scholar
- 4.E-waste Market Grew Nearly 10% in 2010; Growth Expected Through Decade. URL https://www.sbireports.com/about/release.asp?id=2468 (2011) (accessed 3.4.17).
- 5.Meyer L, and Bras B, in Proc. International Symposium on Sustainable Systems and Technology, IEEE, Chicago, p 1 (2011).Google Scholar
- 6.Statistics for Lighting Industry in India, 2015. URL http://www.elcomaindia.com/wp-content/uploads/FINAL_2015_Lighting_Industry_India.pdf (2015) (accessed 3.15.17).
- 9.Nakamura T, Nishihama S, and Yoshizuka K, Solvent Extr Res Dev, Jpn 14 (2007) 105.Google Scholar
- 14.Li H, Chin J Rare Met 34 (2010) 21.Google Scholar
- 23.Otto R, and Wojtalewicz-Kasprzak A, US Patent 20120027651 A1, (2012).Google Scholar
- 25.Levenspiel O, Chemical Reaction Engineering, 3rd ed., Wiley, London (1999).Google Scholar
- 28.Vaughan D J, and Wogelius R A (Eds.), Environmental Mineralogy II: University Textbook, London European Mineralogical Union and the Mineralogical Society of Great Britain & Ireland, (2013).Google Scholar