The present paper deals with the feasibility of the neodymium recovery from spent Nd–Fe–B magnets using molten salt electrodeposition method. The salt bath consisted of a mixture of LiCl–KCl–NaCl corresponding to the eutectic composition. The experimental set-up with its salient features is presented. AlCl3 was used as flux and graphite rods dipped in the salt bath served as electrodes. The voltage for the electrolysis was chosen on the basis of the decomposition potential of NdCl3. The reaction sequence can be described as
Iron-free neodymium deposition could be carried out successfully. In view of the proximity of the electrode potentials, the co-deposition of the aluminium and neodymium was observed to occur at the cathode, as revealed by SEM/EDS and XRD analyses of the electrodeposit.
BarbanelYA, KolinVV, KotlinVP and LumpovAA. 1990. Coordination chemistry of actinides in molten salts, J. Radioanal. Nucl. Chem., 143, 167–179. doi: 10.1007/BF02117559
2.
BermejoMR, GomezJ, MedinaJ, MartinezAM and CastrillejoY. 2006. The electrochemistry of gadolinium in the eutectic LiCl–KCl on W and Al electrodes, J. Electroanal. Chem., 588, 253–266. doi: 10.1016/j.jelechem.2005.12.031
3.
CastrillejoY, BermejoMR, BarradoAI, PardoR, BarradoE and MartinezAM. 2005a. Electrochemical behaviour of dysprosium in the eutectic LiCl–KCl at W and Al electrodes, Electrochim. Acta, 50, 2047–2057. doi: 10.1016/j.electacta.2004.09.013
4.
CastrillejoY, BermejoMR, BarradoE and MartinezAM. 2006a. Electrochemical behaviour of erbium in the eutectic LiCl–KCl at W and Al electrodes, Electrochim. Acta, 51, 1941–1951. doi: 10.1016/j.electacta.2005.07.004
5.
CastrillejoY, BermejoMR, BarradoE, MartinezAM and Diaz ArocasP. 2003. Solubilization of rare earth oxides in the eutectic LiCl–KCl mixture at 450°C and in the equimolar CaCl2–NaCl melt at 550°C, J. Electroanal. Chem., 545, 141–157. doi: 10.1016/S0022-0728(03)00092-5
6.
CastrillejoY, BermejoMR, BarradoE, MedinaJ and MartinezAM. 2006b. Electrodeposition of Ho and electrochemical formation of Ho–Al alloys from the eutectic LiCl–KCl, J. Electrochem. Soc., 153, (10), C713–C721. doi: 10.1149/1.2257971
7.
CastrillejoY, BermejoMR, Diaz ArocasP, MartinezAM and BarradoE. 2005b. Electrochemical behaviour of praseodymium (III) in molten chlorides, J. Electroanal. Chem., 575, 61–74. doi: 10.1016/j.jelechem.2004.08.020
8.
ChambersMF and MurphyJE. 1989. Proc. Rare Earths, Extraction, Preparation and Applications, TMS (eds. BautistaR G and WongM M) 369–376, Warrendale, PA.
9.
CharlotG and TremillonB. 1963. Les reactions chimiques dons les solvants et les sels fondus, Paris, Gauthier-Villars.
De CórdobaG, LaplaceA, ConocarO, LacquementJ and CaravacaC. 2008. Determination of the activity coefficient of neodymium in liquid aluminium by potentiometric methods, Electrochim. Acta, 54, 280–288. doi: 10.1016/j.electacta.2008.08.002
FukasawaK, UeharaA, NagaiT, FujiiT and YamanaH. 2011a. Electrochemical and spectrophotometric study on neodymium ions in molten alkali chloride mixtures, J. Alloys Compd., 509, 5112–5118. doi: 10.1016/j.jallcom.2011.01.192
14.
FukasawaK, UeharaA, NagaiT, FujiiT and YamanaH. 2011b. Electrochemical and spectrophotometric study on trivalent neodymium ion in molten binary mixtures of LiCl and alkali earth chlorides, J. Nucl. Mater., 414, 265–296. doi: 10.1016/j.jnucmat.2011.04.002
15.
GeX and SeetharamanS. 2010. The salt extraction process: a novel route for metal extraction Part 2 – Cu/Fe extraction from copper oxide and sulphides, Miner. Process. Extract. Metall., 119, (2), 93–100. doi: 10.1179/174328510X498116
16.
GeX, GrinderO and SeetharamanS. 2010. The salt extraction process: a novel route for metal extraction Part I – Cr, Fe recovery from EAF slags and low grade chromite ores, Miner. Process. Extract. Metall., 119, (1), 27–32. doi: 10.1179/037195509X12585446038726
17.
GibilaroM, MassotL, ChamelotP and TaxilP. 2008. Study of neodymium extraction in molten fluorides by electrochemical co-reduction with aluminium, J. Nucl. Mater., 382, 39–45. doi: 10.1016/j.jnucmat.2008.09.004
18.
GibilaroM, MassotL, ChamelotP and TaxilP. 2009b. Co-reduction of aluminium and lanthanide ions in molten fluorides: application to cerium and samarium extraction from nuclear wastes, Electrochim. Acta., 54, 5300–5306. doi: 10.1016/j.electacta.2009.01.074
19.
GibilaroM, MassotL, ChamelotP, CassayreL and TaxilP. 2009a. Electrochemical extraction of europium from molten fluoride media, Electrochim. Acta, 55, 281–287. doi: 10.1016/j.electacta.2009.08.052
20.
HallemansB, WollantsP and RoosJR. 1995. Thermodynamic assessment of the Fe-Nd-B phase diagram, J. Phase Equilib., 16, (2), 137–149. doi: 10.1007/BF02664851
21.
HamannCH, HamnettA and VielstichW. 2007. Electrochemstry, 2nd edn, Wienheim, Wiley-VCH.
22.
HamelC, ChamelotP and TaxilP. 2004. Neodymium(III) cathodic processes in molten fluorides, Electrochim. Acta, 49, 4467–4476. doi: 10.1016/j.electacta.2004.05.003
23.
HanW, ChenQ, SunY, JiangT and ZhangM. 2011. Electrodeposition of Mg-Li-Al-La alloys on inert cathode in molten LiCl-KCl eutectic salt, Metall. Mater. Trans. B, 42B, 1367–1375. doi: 10.1007/s11663-011-9567-5
24.
ItoY and NohiraT. 2000. Non-conventional electrolytes for electrochemical applications, Electrochim. Acta, 45, 2611–2622. doi: 10.1016/S0013-4686(00)00341-8
25.
KhalaghiB, TengLD and SeetharamanS. 2012. Proc. 9th Int. Conf. on ‘Molten slags, fluxes and salts’, Beijing, China. May 2012.
26.
LevkowitzL. 2010. China's rare earths industry and its role in the international market, U.S.-China Economic and Security Review Commission.
27.
LiQ and BjerrumNJ. 2002. Aluminum as anode for energy storage and conversion: a review, J. Power Sources, 110, 1–10. doi: 10.1016/S0378-7753(01)01014-X
28.
LichumH and OsteryoungRA. 1981. Chemical and electrochemical studies in room temperature aluminium halide containing melts, in Ionic liquids, (eds. InmanD and LoveringD G), New York, Plenum Press.
29.
MassetP, KoningsRJM, MalmbeckR, SerpJ and GlatzJP. 2005. Thermochemical properties of lanthanides (Ln = La, Nd) and actinides (An = U, Np, Pu, Am) in the molten LiCl–KCl eutectic, J. Nucl. Mater., 344, 173–179. doi: 10.1016/j.jnucmat.2005.04.038
30.
MishraB and OlsonDL. 2005. Molten salt applications in materials processing, J. Phys. Chem. Solids, 66, 396–401. doi: 10.1016/j.jpcs.2004.06.049
31.
NourryC, MassotL, ChamelotP and TaxilP. 2009. Electrochemical reduction of Gd(III) and Nd(III) on reactive cathode material in molten fluoride media, J. Appl. Electrochem., 39, 927–933. doi: 10.1007/s10800-008-9740-y
32.
OkabeTH, TakedaO, FukudaK and UmetsuY. 2003. Direct extraction and recovery of neodymium metal from magnet scrap, Mater. Trans., 44, (4), 798–801. doi: 10.2320/matertrans.44.798
33.
RampinI, BisagliaF and DabalaM. 2010. Corrosion properties of NdFeB magnets coated by a Ni/Cu/Ni layer in chloride and sulfide environments, J. Mater. Eng. Perform., 19, (7), 970–975. doi: 10.1007/s11665-009-9568-6
34.
SeetharamanS and GrinderO. 2010. US patent application nr. 12/991128, ref. no.: 12057.
35.
SerpJ, AllibertM, TerrierAL, MalmbeckR, OugierM, RebizantJ and GlatzJP. 2005. Electroseparation of actinides from lanthanides on solid aluminum electrode in LiCl-KCl eutectic melts, J. Electrochem. Soc., 152, (3), C167–C172. doi: 10.1149/1.1859812
36.
ShirayamaS and OkabeTH. 2009. Selective extraction of Nd and Dy from rare earth magnet scrap into molten salt. The minerals, metals and Materials Society, 3rd Int. Conf. on Processing Materials for Properties, 2008, Vol. 1, 469–474.
37.
StefanidakiE, HasiotisC and KontoyannisC. 2001. Electrodeposition of neodymium from LiF–NdF3–Nd2O3 melts, Electrochim. Acta, 46, 2665–2670. doi: 10.1016/S0013-4686(01)00489-3
38.
TakedaO, OkabeTH and UmetsuY. 2006. Recovery of neodymium from a mixture of magnet scrap and other scrap, J. Alloys Compd., 40, (8–412), 387–390. doi: 10.1016/j.jallcom.2005.04.094
39.
TaxilP, ChamelotT, MassotL and HamelC. 2003. Electrodeposition of alloys or compounds in molten salts and applications, J. Min. Metall., 39, (1–2) B, 177–200. doi: 10.2298/JMMB0302177T
40.
TengLD, SeetharamanS, YamaguchiK and IzumiY. 2013. Patent WO2013025169 (A1).
41.
TsudaT, HusseyCL and StaffordGR. 2004a. Electrodeposition of Al-Mo alloys from the Lewis acidic aluminum chloride-1-ethyl-3-methylimidazolium chloride molten salt, J. Electrochem. Soc., 151, (6), C379–C384. doi: 10.1149/1.1704611
42.
TsudaT, HusseyCL, StaffordGR and BonevichJE. 2003. Electrochemistry of titanium and the electrodeposition of Al-Ti alloys in the lewis acidic aluminum chloride-1-ethyl-3-methylimidazolium chloride melt, J. Electrochem. Soc., 150, (4), C234–C243. doi: 10.1149/1.1554915
43.
TsudaT, HusseyCL, StaffordGR and KongsteinO. 2004b. Electrodeposition of Al–Zr alloys from Lewis acidic aluminum chloride-1-ethyl-3-methylimidazolium chloride melt, J. Electrochem. Soc., 151, (7), C447–C454. doi: 10.1149/1.1753231
44.
UdaT. 2002. Recovery of rare earths from magnet sludge by FeCl2, Mater. Trans., 44, (1), 55–62. doi: 10.2320/matertrans.43.55
45.
VeluPT and ReddyRG. 2005. Calciothermic reduction of neodymium fluoride, in Light metals, 134th TMS Annual Meeting. 2005, 1155–1159.
46.
WuI, ZhuH, SatoY, YamamuraT and SugimotoK. 1994. Proc. 9th International Symposium on Molten Salts (eds. HusseyC L, NewmanD S, MamantovG and ItoY) 504, NJ, Pennington, The Electrochem. Soc Proc. Series.
47.
YamanaH, ParkBG, ShiraiO, FujiiT, UeharaK and MoriyamaH. 2006. Electrochemically produced divalent neodymium in chloride melt, J. Alloys Compd., 408–412, 66–70. doi: 10.1016/j.jallcom.2005.04.104
