Figueiredo, M. Ondina

Oliveira, Daniel P. S.

Rosa, Diogo R. N.

Silva, Teresa

Silva, Teresa Pereira

Laboratório Nacional de Energia e Geologia Repository

How metallic is the binding state of indium hosted by excess-metal chalcogenides in ore deposits [Abstract]

de Oliveira, Daniel Pipa Soares

Rosa, Diogo

Repositório do LNEG

Geophysical Research AbstractsVol. 12, EGU2010-10673, 2010EGU General Assembly 2010© Author(s) 2010How metallic is the binding state of indium hosted by excess-metalchalcogenides in ore deposits?Maria Ondina Figueiredo (1,2), Teresa Pena Silva (1,2), Daniel Oliveira (1,3), Diogo Rosa (1,3)(1) LNEG, Geological Data Centre, Apartado 7586, 2721-866 Alfragide, Portugal, (2) CENIMAT/I3N, Materials Sci. Dept.,Fac. Sci.Technol., New Univ. Lisbon, 2829-516 Caparica, Portugal, (3) CREMINER, C. Min. Resources, Mineralogy &Cryst., Fac. Sci., Univ. Lisbon, Edif. C6, 1749-016 Lisbon, PortugalDiscovered in 1863, indium is nowadays a strategic scarce metal used both in classical technologic fields (likelow melting-temperature alloys and solders) and in innovative nano-technologies to produce “high-tech devices”by means of new materials, namely liquid crystal displays (LCDs), organic light emitting diodes (OLEDs) andthe recently introduced transparent flexible thin-films manufactured with ionic amorphous oxide semiconductors(IAOS).Indium is a typical chalcophile element, seldom forming specific minerals and occurring mainly dispersed withinpolymetallic sulphides, particularly with excess metal ions [1]. The average content of indium in the Earth’s crustis very low but a further increase in its demand is still expected in the next years, thus focusing a special interestin uncovering new exploitation sites through promising polymetallic sulphide ores – e.g., the Iberian Pyrite Belt(IPB) [2] – and in improving recycling technologies. Indium recovery stands mostly on zinc extraction fromsphalerite, the natural cubic sulphide which is the prototype of so-called “tetrahedral sulphides” where metal ionsfill half of the available tetrahedral sites within the cubic closest packing of sulphur anions where the double ofunfilled interstices are available for further in-filling. It is worth remarking that such packing array is particularlysuitable for accommodating polymetallic cations by filling closely located interstitial sites [3] as happens inexcess-metal tetrahedral sulphides – e.g. bornite, ideally Cu5FeS4, recognized as an In-carrying mineral [4].Studying the tendency towards In-In interactions able of leading to the formation of polycations would effi-ciently contribute to understand indium crystal chemistry and the metal binding state in natural chalcogenides.Accordingly, an X-ray absorption near-edge spectroscopy (XANES) study at In L3-edge was undertaken using theinstrumental set-up of ID21 beamline at the ESRF (European Synchrotron Radiation Facility, in Grenoble/France).Polymetallic chalcogenide minerals and various model compounds displaying distinct bonding situations ofindium to other ligands (oxygen and halides) were studied. Encouraging results from a first experiment [5] showedthe presence of a ”white line” in the XANES spectra collected from InF3 and from In-hosting bornite; however,the impossibility of clearly identifying the nanoscale phase hosting indium in sulphide ore samples has hindered afull interpretation of X-ray absorption data.The crystal chemistry of indium in natural chalcogenides is now reanalysed and XANES results obtained so farfor polymetallic sulphides are accordingly re-evaluated, disclosing a challenging clue for indium binding state inthese host minerals within sulphide ores.[1] M.O. Figueiredo et al. (2007) Procd. 9th Biennial SGA Mtg., Dublin/Ireland, edt. C. Andrew et al.,1355-1357. [2] O.C. Gaspar (2002) Canad. Miner. 40, 611-636. [3] M.O. Figueiredo & T.P. Silva (2009) ICANS23, 23rd Int. Conf. Amorphous & Nano-crystalline Semiconductors, Netherlands, August 23-28. Poster ID 229(abstract). [4] T. Seifert & D. Sandmann (2002) Ore Geol. Reviews 28, 1-31. [5] M.O. Figueiredo & T.P. Silva(2009) XVIII Int. Mater. Res. Congr., Mexico, August 16-20. Symp. 20, Poster nr. 1 (abstract).* Work developed within the research project PTDC/CTE-GIN/67027/2006 financed by the PortugueseFoundation for Science & Technology (FCT/MCTES). The financial support from EU to perform the experimentsat the ESRF is also acknowledged.

ResultsA similar general trend is displayed by In L3-edge XANES spectra from model compounds In F3 & In2 O3, both containing In3+ (fig.8a), and from two irradiated points in ore sample LS 5-180.6.Indium fluoride XANES spectrum shows an intense “white line” at 3732.1eV, also visible - despite weak - in the oxide spectrum. A second shoulder with similarfeature occurs in both spectra respectively at 3745.5 eV and 3744.5 eV.  Comparatively to the details observed for the model compounds, chalcogenide ore spectra show an additional weak white-line at 3726.5 eV (fig.8b).XL - 230European Geosciences UnionGeneral  Assembly 2010Vienna / Austria, 2-7 MayGMPV 30 – Geochemistry, Mineralogy, Petrology & VolcanologyA Brief Survey of In Crystal ChemistryAssigned in Transbaikalia as a native metal associated with lead [7], indium (Z=49) has the electronic structure [Kr] 4d10 5s2 5p1, and frequently assumes the trivalent state, thus suggesting the inertness of  5s2 electron-pair. Similarly to gallium but unlike tin – two other important “high-tech” metals - indium seldom forms specific minerals. Roquesite(CuInS2) was the first indium mineral to be described [8], followed by indite (Fe In2 S4) and dzhalindite, In (OH)3, the latter with octahedral In3+ [9].Indium is mainly carried by sphalerite in Nature, either in solid solution or diadochic replacement and by excess-metal copper-rich“tetrahedral sulphides” like bornite, Cu5tFet [S4t ] c. Only veryseldom does indium form specific minerals, an example beingsakuraite, (Cu,Ag)2t (Zn,Fe)t (In,Sn)t [S4t ] c. However, the structural study of synthetic chalcogenides [10,11] – In6Se7, In4Se3, In4Te3, InTe, In7Te10 – has revealed the presence of polymetallic indium ions – [In2]4+ dimmers and [In3]5+ trimers (fig.4).ProblematicAscertaining the tendency to establish In-In interactions capable of leading to the formation of metallic polycations would efficiently contribute to the under-standing of Incrystal chemistry and binding state in natural chalcogenides. Accordingly, an X-ray absorption near-edge spectroscopy (XANES) study was undertaken at the ESRF (European Synchrotron Radiation Facility, Grenoble/France). A first experiment [12] has disclosed the presence of a ”white line” [13] in the XANES spectra collected from InF3 (fig.5) and from one sample of sulphide ore (fig.6) but the impossibility of clearly identifying the nanoscale phase hosting indium has hindered a full interpretation of X-ray absorption data.Acknowledgements*  Work developed within the project PTDC/CTE-GIN/67027/2006 financed by the Foundation for Science & Technology (MCTES). The financial support of  EU to perform experiment EC-290 & -450 at the ESRF is acknowledged.MAIN CRYSTAL STRUCTURE-TYPES (STP) of NATURAL CHALCOGENIDES (Minerals)Crystal chemical formulae according to J. Lima-de-Faria&  M.O. Figueiredo (1976) J. Solid State Chem. 16 7-12.Tetrahedral SulfidesWURTZITE(hexagonal closest-packing of anions)Znt [S t]hBLENDEorSPHALERITEZnt [S t]cS=  anionsFig. 2|S=S|= dimersDisulfidesFeo [ | S2t | ] <c>PYRITESULPHO-SALTS :Polysomaticseriesmade-upfrom slabsextractedfrom galenastructurePbPbo [So]cGALENAOctahedral SulfidesSSuperstructures: 1) lacunar closest-packings2) insertion of extra cationsFig. 1Iberian Pyrite Belt (IPB)ESRFGrenoble/FranceID 21beamlineFig. 7Fig. 6 – Photomicrograph ofa polished section from oresample  LS 5-180.6 fromLagoa Salgada [15]. A fissure is shown in black.Dark grey, pyrite (FeS2);light grey, sphalerite (ZnS);white, galena (PbS).100 μmZn SFe S2Pb SFe S2References[1] E. FORTUNATO, et al. (2005) Advanced Materials 17, 590-594.[2] M.O. FIGUEIREDO et al. (2007) Procd. 9th Biennial SGA Mtg.,Dublin/Ireland, edt. C.Andrew et al., 1355-1357 (ISBN 0-950989-4-4).[3] O.C. GASPAR (1984) Memorias & Notícias, Museu Lab. Miner. Geol., Univ. Coimbra, 98, 137-150. (in Portuguese).[4] M.O. FIGUEIREDO & T.P. SILVA (2009) ICANS 23, Int. Conf. Amorph. & Nanocryst. Semicond., Netherlands, August 23-28. Abstr.[5] T. SEIFERT & D. SANDEMANN (2002) Ore Geol. Rev. 28, 1-31.[6] J. LIMA-de-FARIA (1965) Zeit. für Kristallogr. 122, 346-358.[7] V.V. IVANOV (1964) Cf. Handbook of Geochemistry (1974)  Springer-Verlag, vol. II-4, p. 49-A.[8] P. PICOT & R. PIERROT (1963) Bull. Soc. Fr. Min. Crist. 86, 7-11.[9] A.D. GENKIN & I.V. MURAVEVA (1963) Zap. Vses. Mineralog. Obshsestva 92, 445 (in Russian). Cf. Amer. Min. 49, 439 (1964).[10] H. SCHWARTZ, et al. (1995) Zeit. für Kristallogr. 210, 342-347.[11]  M. EPPLE, et al. (2000) Zeit. für Kristallogr. 215, 445-453.[12]  M.O. FIGUEIREDO & T.P. SILVA (2009) XVIII Int. Mat. Res. Congress, Cancún/México, August 16-20. Abstract.[13]  M. BROWN et al. (1977) Phys. Rev. B 15, 738-744.[14] R. HOPPE & D. KISSEL (1984)  J. Fluorine Chem. 24, 327-340.[15] D. OLIVEIRA et al. (2009) Proc. 10th Biennial SGA Mtg.,Townsville/Australia, edt. P.J.Williams et al., vol.1, 424-426.[16] J. SUSINI et al. (2000) Proc. 6th Internat. Conf. X-Ray Microscopy,Amer. Inst. Phys. 507, 19-28.[17] J. T-THIERPRASERT et al. (2008) Appl. Phys. Lett. 93,  051903[18]  T. MIYAMOTO et al. (2010) J.Phys. Chem. A 114, 4093-4098.[19] V. SUBRAMANIAN, et al. (2004)  Solid St. Ionics 175, 181-184.[20]  T.K. SHAM (1985) Phys. Rev. B 31, 1888-1902. [21]  M. WOMES et al. (2004) Solid State Comm. 131, 257-260. ExperimentalX-ray absorption experiments at In L3-edge were carried out using the instrumental set-up of ID-21 beamline (fig.7).Polymetallic chalcogenide ores (In~90ppm) from Lagoa Salgada [15] wereirradiated, along with metallic indium and various model compounds displaying distinct bonding situations of In to other ligands (oxygen and halides).XANES spectra were collected in fluorescence yield (FY) mode using a photodiode detector mounted in the horizontal plane perpendicular to the X-ray beam. Small sample fragments were irradiated with a beam-size of 1x0.3μm2. A fixed-exit Si (111) monochromator was used, assuring a good energyresolution at the In L3-edge (0.4 eV).Comments  and  conclusions  The presence of a “white line” [12] in In L3-edge XANES spectrum denotes non-occupied electronic states in In atoms as pointed out in a recent study [17] on indium oxynitride (wurtzite-type structure) (fig.9).By analogy with silver [18], such edge-shoulder can beformally assigned to the transition from 2p to 5s state enhanced by an s-d hybridization.Although the In L3-edge spectra from indium oxide was already studied in the context of ITO thin-films [19] and the spectra of the metal was discussed a few years ago [20],further study is clearly required to fully interpret the spectra collected from natural chalcogenides - also distinct from the XANES spectra of synthetic spinel-type In2S3 [21].The closest packing array built up by S= anions in the minerals present in ore sample LS5-180.6 (fig.6) − chalcopyrite, sphalerite, galena − is very suitable to lodge polymetallic cations by filling-in closely located interstitial sites. The condensed-model sheet of a single anionic layer figuring out the interstices available between successive packinglayers clearly illustrated this (fig.3). Considering that In F3 is also a hexagonal closest-packed compound (fig.5), it is liable that interactions may occur between neighbor Incations, thus accounting for singularities of the observed white lines. Further study is in progress to explore this hypothesis.IntroductionDiscovered in 1863, indium is a strategic scarce metalused both in classical technologic fields (e.g. low melting-temperature alloys & solders) and innovative nanotechnologies to produce “high-tech devices” using new materials, namely liquid crystal displays (LCDs), organic light emitting diodes (OLEDs), transparent flexible thin-films [1]with ionic amorphous oxide semiconductors (IAOS).Indium is a typical chalcophile element, seldom forming specific minerals and occurring mainly dispersed within poly-metallic sulphides, particularly with excess metal ions [2]. The average content of indium in the Earth's crust is very low but a further increase in In demand is still expected in next years, thus focusing a special interest in uncovering new exploitation sites through promising polymetallic sulphide ores – like the Iberian Pyrite Belt (fig.1) [3] – and in improving the recycling technologies. Indium recovery stands mostly on zinc extraction from sphalerite – the prototype of “tetrahedral sulphides”, where zinc cations fill half of the available tetrahedral sites in a cubic closest packing of sulphide anions (fig.2). It is worth remarking that this anionic packing (fig.3) is particularly suitable to accommodate polymetallic cations in closeinterstitial sites [4], as happens in excess-metal sulphides like bornite, known to be an In-carrier mineral [5].The crystal chemistry of In in natural chalcogenidesis reanalysed and X-ray absorption near-edge spectroscopy data so far obtained for polymetallic sulphides are discussed,disclosing a clue for In binding state in host minerals.In4Se3TrimersIn6Se7DimersFig. 4 − [In 2]4+ & [In3]5+Polycations [11]HOW  METALLIC  IS  THE  BINDING  STATE  OF  INDIUM  HOSTED  BY  EXCESS-METAL  CHALCOGENIDES  IN  ORE  DEPOSITS ? *M.O. FIGUEIREDO1,2 , T.P. SILVA1,2 , D.P.S. de OLIVEIRA1,3 ,  D.R.N. ROSA1,31 INETI / LNEG, Geological Data Centre, Apartado 7586, 2721-866 Alfragide, 2 CENIMAT / I3N, Materials Sci. Dept., Fac. Sci.Technol., New Univ. Lisbon, 2829-516 Caparica,3 CREMINER, C. Min. Res., Miner. & Cryst., Fac. Sci., Univ. Lisbon, Ed.C6, 1749-016 Lisbon, PortugalIN• • •Fig. 5 - Crystal structureof trigonal InF3  [14],with ideal crystal chemical formulaIno[F3]h  In3+ ions fill only1/3 of the available octahedral sites.cInFX     ADotFig. 3 - Condensed-model standard sheet [6]for               At2 D o[X]c / hLarge circles, closest packed atoms (X); A, tetrahedral (t),  and D, octahedral (o) sites.Ideal radii: rt=0.225 rX; ro=0.414 rX[t-o] and [t-t] distances are illustrated.Fig. 9 – In L3-edgeXANES spectra ofindium oxynitride,considered as an“alloy” phase [17]. Nitrogen-to-oxygenproportions inwurtzite-type InNsamples are indicated.Energy range: 2 - 7.5 KeVSketch of ID-21 beamline [16]Beam direction(a)3 732.13 745.53 760In (metal)In BrIn2O3In F3E (eV)3 744.53 757Fig. 8 − In L3-edge  XANES spectra(a) model compounds;  (b) points inchalcogenide sample LS5-180.63 732.53 726.53 757.53 742.5(b)s1s2p1p2Modified from[17], fig.2(a)3 7463 735

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How metallic is the binding state of indium hosted by excess-metal chalcogenides in ore deposits [Poster]

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How metallic is the binding state of indium hosted by excess-metal chalcogenides in ore deposits [Abstract]

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