Contents lists available at ScienceDirect Minerals Engineering journal homepage: www.elsevier.com/locate/mineng Yttrium and europium recycling from phosphor powder of waste tube light by combined route of hydrometallurgy and chemical reduction Bibhuti Bhusan Mishra a , Niharbala Devi a, ⁎ , Kadambini Sarangi b a Department of Chemistry, Institute of Technical Education and Research, Siksha ‘O’Anusandhan [Deemed to be University], Bhubaneswar 751030, Odisha, India b CSIR-Institute of Minerals and Materials Technology, Bhubaneswar 751013, Odisha, India ARTICLE INFO Keywords: Tube light powder Separation Reduction Precipitation D2EHPA Cyphos IL 104 ABSTRACT This paper deals with the recovery of yttrium and europium from waste tube light phosphor powder leach liquor using solvent extraction and chemical reduction route. Hydrochloric acid (2 mol/L) is used as the leachant to generate the leach liquor. From the leach liquor, the separation of Y(III) and Eu(III) is carried out with three types of extractants (acidic, neutral and ionic liquid) with extractant concentration and pH variation. Highest separation factor of 60.6 is achieved with 0.1 mol/L D2EHPA at aqueous phase pH of 2.56. The quantitative extraction of yttrium from the leach liquor is achieved in two counter current stages at O:A ratio of 1:1.5 at pH 2.56. After extraction of yttrium, yttrium oxalate is prepared by precipitation stripping with 0.4 mol/L oxalic acid. The stability and reusability of the extractant is also investigated. The reduction process with zinc helps to reduce 78% of Eu (III) to Eu (II) but 16% Y(III) is precipitated as yttrium sulfate along with Eu(II) precipitation. A tentative flow-sheet is developed for the whole process. 1. Introduction The economic importance of rare earths has skyrocketed in the past couple of years because of use of these elements in high technology equipment. They are used in magnets, phosphors, lasers, high tem- perature super conductors for safe storage of hydrogen. The green en- ergy initiatives depend on RE oxides. Due to over-exploitation, many countries are facing problem for these resources. Hence, there is a boost for recycling the end of life products as in many e-wastes these metals are present. Some wastes include phosphor powder that is present in the inner wall of the exhausted fluorescent lamps, dead batteries like NiMH, SmCO 5 , Sm 2 CO 17 , cathode ray tubes etc. Development of sui- table processes to recover the REE’s are the main goal of many re- searchers from last few years. As ∼65% fluorescent lamps are used in commercial purposes, it could be a huge secondary source for re- claiming the rare earth metals. It contain red, green and blue phosphor having composition Y 2 O 3 :Eu 3+ (red), LaPO 4 :Ce 3+ , Tb 3+ /(GdMg) B 5 O 12 Ce 3+ ,Tb 3+ /(Ce,Tb)MgAlO 19 (Green) and BaMgAl 10 O 17 :Eu 2+ (Blue) (Ronda 1995; Binnemans et al., 2013; Innocenzi et al., 2018). After physical separation, leaching and solvent extraction of hydro- metallurgical route has been carried out to recover the REE’s. Red phosphor containing Y and Eu could be leached using dilute acids (Pavón et al., 2018; Liu et al., 2014) is the focus of the current work. From literature, it is found that many extractants are used for extraction and separation of rare earth elements (Parhi et al., 2016; Padhan et al., 2017; Padhan and Sarangi, 2018; Benedetto et al., 1995; Li et al., 2007a; Li et al., 2007b; Santhi et al., 1991; Zheng et al., 1991; Fontana and Pietrilli, 2009; Sato,1989; Turanov et al., 2004; Gupta et al., 2003; Shimizu et al., 2005; Yang et al., 2012; Rout and Binnemans, 2015; Larsson and Binnemans, 2015; Quinn et al., 2017; Jia et al., 2009; Desouky et al., 2009; Tunsu et al., 2016a, Yin et al., 2018). Turanov et al., (2004), reported the extraction of REEs from nitric acid solution using bifunctional acidic organophosphorus compounds R 2 P(O)CH 2 P (O)Ph(OH) where R 2 may be di-phenyl, di-octyl, di-p-tolyl etc. From these, Eu(III)-Y(III) extraction favors with p-methoxy phenyl or octyl substituents. Using Cyanex 923 as an extractant for extraction and se- paration of rare earth metals from different acid media, Gupta et al. (2003), showed that it is a potential extractant for the development of a suitable method for separation of lanthanides but the concentration of extractant is comparatively high (0.5 mol/L) with respect to metal concentration (100 mg/L). Five ionic liquids with bis(tri- fluromethylsulfonyl) imide anion are used as diluent for Cyanex 923 to study the extraction of trivalent REEs (Rout and Binnemans, 2015). The study reported that the extraction of REEs depends on the type of ionic liquid cation. Quinn et al., (2017), reported the extraction of REEs using a bifunctional ionic liquid quaternary ammonium phosphonate ‘R 4 N + EHEHP - ’ formed from Aliquat 336 (trioctyldecylmethylammo- nium chloride) and EHEHPA (2-ethylhexylphosphonic acid 2- https://doi.org/10.1016/j.mineng.2019.03.007 Received 5 October 2018; Received in revised form 8 March 2019; Accepted 8 March 2019 ⁎ Corresponding author. E-mail address: niharbaladevi@soa.ac.in (N. Devi). Minerals Engineering 136 (2019) 43–49 0892-6875/ © 2019 Elsevier Ltd. All rights reserved. T