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Mineral Profile Niobium

Mineral Profile Niobium

MineralsUK profile Centre for sustainable mineral development per cent urally-occurring niobiumconsistsalmostexclusivelyofthe isashiny, ductilemetalwithawhitelustre.Nat- Anders Ekeberg. Tantalum wasdiscoveredin1802byaSwedishscientist, some time,before‘niobium’wasfinallyacceptedin1949. it ‘niobium’.Thenameswereusedinterchangeablyfor nised byaGermanchemist,HeinrichRose,whonamed named ‘columbium’;itwassubsequentlyalsorecog- discovered in1801byCharlesHatchett,andwasoriginally thus commonlygroupedtogether(Table 1).Niobiumwas very similarphysicalandchemicalproperties,are Niobium (Nb)andtantalum(Ta) aretransitionmetalswith Definitions andcharacteristics deposits Definitions, mineralogyand economically importantspecies areoxides. typically havelowconcentrations.Thevastmajorityofthe for majorionsinanumberofotherminerals,whichthey are relativelyrare.Niobiumandtantalumalsosubstitute ; silicatesofniobiumandtantalumdoexist,but mineral species(Table 2).The majorityoftheseareoxide , butareessentialcomponentsinarangeof Niobium andtantalumdonotoccurnaturallyasfree Mineralogy are typicallydepletedinbothniobiumandtantalum. subduction zones,andthatmagmasformedinthissetting continental crustwasformedatconvergentmarginsabove crust. Thiscanbeattributedtothefactthatmuchof bium andtantalumareratherdepletedinthecontinental other metallicelementssuchasthelightrareearths,nio- tantalum of0.7ppm(RudnickandGao,2004).Comparedto having anabundanceofeightpartspermillion(ppm)and average continentalcrustarerelativelylow, niobium The overallabundancesofniobiumandtantaluminthe both elementshavebeensynthesised. BGS ©NERC2011. Allrightsreserved. contained inthisreportarevested inNERC. Unless otherwisestated,copyright ofmaterials 93 180 Nb; naturaltantalumismainly Ta. Anumberofotherradioactiveisotopes Niobium–tantalum 181 Ta, with0.012 Lavinsky, iRocks.com (http://www.irocks.com/) iRocks.com Lavinsky, licence (accessed25/03/2011 atwww 1 Table 1 Figure 1 found asaprimarymineralinalkalineigneousrocks. rich inbothniobiumandtantalum.Pyrochloreistypically has awidecompositionalrange,includingsomespecies economic importance,particularlyforniobium.Thisgroup tantalum. Thepyrochloregroup(Figure2)isofgreat minerals. isalsoan important sourceof most commongroupoftantalum-andniobium-bearing The -tantalitemineralgroup(Figure1)isthe

tmcwih 2968180.9479 92.90638 (g/cm 41 at293K Atomic weight rsa tutr Bodycentred ohm-metres) resistivity (nano Electrical 4930 MPa 2468 Vickers hardness °C °C Image takenbyRob Lavinsky. Permissiontousegiven byacreativecommons 3

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Selected propertiesofniobiumandtantalum. Dark colouredtantalitewithpale colouredalbite ibu N)Tantalum (Ta) Niobium (Nb) 5 t0C131at20°C 152 at0°C .8 16.677 8.581 cubic 1320 .commons.wikimedia.org). Attribution:Rob

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CC-BY -SA-3.0. Body centred cubic 5425 2996 873 73 April 2011 1 . 2 Niobium–tantalum Lavinsky, licence (accessed25/03/2011 atwww Table 2 2 Figure 2 (Na those foundinalkalineigneous rockssuchaseudialyte as substitutesinarangeofsilicate minerals,typically economic interest.Similarly, niobiumandtantalumoccur these mineralsarerarelyhighenoughtomakethemof , andilmenite.Contentsofniobiumtantalumin ions insomecommonoxidegroupssuchascassiterite, . Niobiumandtantalumalsosubstituteformajor include ,,andmineralsoftheperovskite Other, lesscommonoxidesofniobiumandtantalum

oubt oubt-atlt (Fe,Mn)(Nb,Ta) Columbite- Columbite iea aeMnrlgopFormula Mineralgroup Mineral name leouieRutile Rutile Ilmenorutile Struverite Wodginite Loparite Wodginite Ixiolite yohoePyrochlore Pyrochlore Lueshite Tantalite Tapiolite Image takenbyRob Lavinsky. Permissiontousegiven byacreativecommons 4 (Ca,Ce) iRocks.com (http://www.irocks.com/) iRocks.com

Selected niobiumandtantalummineralsindicativecontents ofNb Pyrochlore. Source:RobLavinsky(iRocks.com) 2 (Fe ++ ,Mn,Y)ZrSi Euxenite Perovskite Ixiolite Perovskite oubt-atlt (Fe,Mn)(Ta,Nb) Columbite-tantalite Tapiolite Pyrochlore 8 O .commons.wikimedia.org). 22 (OH,Cl)

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CC-BY 2 ). -SA-3.0.

Attribution: Rob (Y, Ca,Ce,U,Th)(Nb,Ti, Ta) (Ce,La,Na,Ca,Sr)(Ti,Nb)O (Ta,Nb,Sn,Mn,Fe) Fe (Ti,Ta,Fe)O (Ta,Nb,Sn,Mn,Fe)O (Na,Ca) NaNbO (Fe,Mn) (Ta,Nb) (Na,Ca) x (Nb,Ta) 2 . 2 2 3 Ta Nb 2x 2 2 2 O 4Ti carbonate minerals. potassium- and/orsodium-rich mineralalkalifeldspar. rock (). monly associatedwithigneousrocks Niobium andtantalummineraldepositsaremostcom- Deposits 6 5 4 3 not known. the categoriesgivenabove,buteconomicexamplesare found insomegranitesandpegmatitesthatdonotfallinto Moderately highcontentsofniobiumandtantalummaybe 3. 2. 1. with whichtheyareassociated(Küster, 2009): into threemaintypes,onthebasisofigneousrocks Primary NiobiumandTantalum depositscanbedivided descriptions below. sources, andsotheyarenotconsideredseparatelyinthe occur inrelativelycloseassociationwiththeirprimary end ofthissection).Ingeneral,thesesecondarydeposits processes, arealsoknown(seeTable 3andFigureatthe have beenconcentratedbyweatheringandsedimentary deposits, whereniobium-andtantalum-bearingminerals O

6 : igneous rocksconsistingofmorethan50percent primary Syenites: coarse-grainedigneousrocksthat arecomposedlargelyofthe Pegmatites: verycoarse-grainedigneous rocks. Igneous rocks:rockswithacrystallinetexture thatcrystallisedfrommolten

6 (O,OH,F) (O,OH,F) 2005). in lithium(Li),(Cs),tantalum)(C andpegmatitesoftheLCTfamily(enriched Alkaline toperalkalinegranitesandsyenites Carbonatites andassociatedrocks 1-x 2 2 2 O O O O 6 6 4 6 2 O 2 8 4 , syenites 3 2 O 6 2 O 5 andTa 5 andcarbonatites 2 O www.MineralsUK.com 5 Nb . 13 37.65 22.53 n.a. 11.32 47.43 81.09 61 n.a. 16.15 87 n.a. 78.72 51 n.a. 75.12 79n.a. 27.9 .769.58 68.96 83.96 8.37 8.30 1.33 2 ..86.17 n.a. ..83.53 n.a. O 5 3 (%) , includinggranites, 6 . Somesecondary ˇ erný andErcit, Ta 2 O 5 (%) 3 Niobium–tantalum magmatic differentiation rarely upto1.0percent),butnotore-grade.However, bodies aremoderatelyhigh(commonly0.01–0.1percent, In general,bulkrockniobiumcontentsforcarbonatite niobium-rich silicatessuchastitanite(Mitchell,2005). the perovskiteandpyrochloremineralgroups,aswell bearing mineralsfoundincarbonatitesincludemembersof high tantalumcontents(Möller rich melts,andsocarbonatitesdonotgenerallyhave preferentially enrichedovertantalumincarbondioxide- zirconium (Zr),uranium(U)andthorium(Th).Niobiumis strontium (Sr),fluorine(F),phosphorus(P),niobium(Nb), including therareearthelements(REE),barium(Ba), Carbonatites aretypicallyenrichedinarangeofelements, and water-rich fluidsratherthanmagmas. surface. are concentratedeither inthecrystallinerockorresidual moltenmagma. rock bytheactionoffluids. rich inmagnesiumand/oriron. magnesium and/oriron. silica contents. rarely occurringaslargeplutonsorextrusive small plugs(lessthanonekilometreindiameter),more Carbonatites aremostcommonlyfoundasdykes,sillsand directly fromthemantlewithverylittlecrustalinfluence. contain certaincharacteristicminerals. Earth’s surface. occurring atthepresentdayinEastAfrica. rifting exclusively foundinareasofcontinentalextensionand 50 percentprimarycarbonateminerals.Theyarealmost Carbonatites areigneousrocksthatconsistofmorethan Carbonatites andassociatedrocks 16 15 14 13 12 11 10 9 8 7 rocks, ormafic rounded byametasomatised and Kjarsgaard,2008).Manycarbonatitebodiesaresur- commonly associatedwithalkaline sequences. Theyrarelyoccurinisolation,beingmore carbohydrothermal . Somecarbonatitebodiesareconsideredtobe alteration ofthecountryrocksbyfluidsderivedfrom rich insodium(Na)and/orpotassium(K),formedthrough pyrochlore. Weathering processes tling mayconcentrateniobium-bearingmineralssuchas nepheline syeniteandotherfeldspathoid-bearing

Alkaline rocks:igneousrocksthatarerichinsodiumandpotassium, Extrusive: extrusivevolcanicrocksareformedbyeruptionofmagmaontothe Continental rifting:thegradualbreak-upofacontinentunderextension,asis Weathering processes:processesbywhichrocksare alteredattheearth’s Magmatic differentiation:processesbywhich certainelementsorminerals Carbohydrothermal: formedfromhotcarbon dioxide-richandwater-rich fluids. Metasomatised: havingundergonemetasomatism, chemicalalterationofa Ultramafic: arockalmostentirelymade up ofdark-colouredmineralsthatare Mafic rock:arockcontainingabundantdark-colouredmineralsthatarerichin Feldspathoids: agroupoflight-colouredmineralsthathaverelativelylow 7 , andtheirsourcemagmasarethoughttobederived 11 toultramafic 14

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formed fromcarbondioxide-rich 15 processessuchascrystalset- 13 12 or‘fenitised’zone,typically alkalinerocks(Woolley , 1989).Commonniobium- 16 9 mayalsoconcentrate silicaterocks,either 8 volcanic 10 igneous cite carbonatite,glimmerite dominated bydolomitecarbonatitewithsubordinatecal- ometre indiameter(NasraouiandWaerenborgh, 2001), Complex, aroughlycircularintrusionapproximately4.5 The AraxádepositlieswithintheBarreiroCarbonatite both deposits,pyrochloreisthemainniobiumoremineral. phoscorite in ratherunusualintrusionsconsistingofcarbonatite-and operated byAngloAmerican.Thesedepositsarehosted (CBMM). Asecondmajorniobiummine,atCatalão,is by theCompanhiaBrasileiradeMetalurgiaeMineraçao niobium depositisatAraxá,andownedexploited been alteredbytheeffects ofincreasedtemperature,pressure orfluidflow. resulting fromweathering undertropicalconditions. biotite orphlogopite.Canalsobecalled biotitite orphlogopititeasappropriate. carbonatites. ago. ultramafic-carbonatite complexesoftheLateCretaceous zil, wherethemainniobiumdepositsoccurinalkaline Much oftheworld’s niobiumsupplycomesfromBra- mineralisation. thermal activity, areathirdpotentialsourceof niobium and areasofmetasomatism,formedthroughcarbohydro- these mineralsintheshallowsubsurface.Late-stageveins 22 21 20 19 18 17 Niobec mineinQuebec,,operatedbytheIamgold The largestactiveniobiummineoutsideBrazilisthe centre ofthecomplex. mined depositisintheweatheredlateriticzoneabove tre ofthecomplex(Cordeiroetal.,2010).AsatAraxá, rocks thatbecomeincreasinglycommontowardsthecen- and plugsofdolomite-carbonatitephoscorite-series (phlogopitite) atthemarginsofcomplex,withsheets six kilometresatthesurface.Itisdominatedbyglimmerite ed, zonedintrusivebodywithadiameterofapproximately in thenearbyCatalãoIIcomplex.Iisasteep-sid- alkaline-carbonatite complex,butasimilardepositoccurs The mainworkeddepositatCatalãoisintheI to 2.5kilometrewide(NasraouiandWaerenborgh, 2001). carbonatite havebeenmetasomatisedinanaureole exploited byopen-pitmining.Thecountryrockstothe mean gradeof2.5percentniobiumoxide,andwhichis which pyrochlorehasbecomeconcentratedatareported zoic Alto Paranaibaigneousprovince,intrudedintoNeoprotero- conditions toformathick(>200metres),lateritic part oftheintrusionhasbeenweatheredundertropical

Aureole: anareaaround abodyofigneousrockinwhichthe host rockshave Lateritic: relatingtolaterite,aresidualdeposit richinironandaluminium Glimmerite: Anultramaficrockconsisting almostentirelyofmica,either Phoscorite: Amagnetite,olivine,apatite rock, usuallyassociatedwith Neoproterozoic: aunitofgeologicaltimebetween1000to542millionyears Late Cretaceous:aunitofgeologicaltimebetween99to65millionyearsago. 18 metasedimentaryrocks.Thelargestcurrentlyworked 19 -series rockswithnoassociatedsyenites.In 20 andphoscorite.Thecentral www.MineralsUK.com 21 coverin 22 up

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4 Niobium–tantalum by riversand/orcoastal processes. usually cylindricalwithsteepmargins. entirely coveredbyPalaeozoic surrounded byaringofsyenitesanddiorites,isalmost ferrocarbonatite (Belzile,2009).Thecarbonatitebodyis from calcitecarbonatitethroughdolomiteto of crescenticlensescarbonatite,younginginwards kilometres acrossatthesurface.Itconsistsofaseries which hasanellipticalshapeandisapproximatelyfour Neoproterozoic-age Saint-Honorécarbonatitecomplex, Corporation. Thismineliesinthesouthernpartof 26 25 24 23 ancient lake,associatedwithPermian upper orehorizonisaburiedplacerdeposit ered andalteredtoptothecarbonatitebody, whilstthe which isupto300metresthick,representstheweath- concentrated intwoorehorizons.Thelowerhorizon, seminated throughoutthecarbonatite,butisparticularly tres (KravchenkoandPokrovsky, 1995).Pyrochloreisdis- having asurfaceareaofapproximately12squarekilome- its mayremaintobefound.The smallerdepositsinclude published work(Bergeretal.,2009)andothersuchdepos- rare earthelementmineraldepositshavebeenrecordedin A totalof58carbonatitebodiescontainingniobiumand with 2897milliontonnesniobium(Pollard,1995). represent thelargestsingleniobiumdepositinworld its ageisuncertain(Bergeretal.,2009),butitthoughtto Seis Lagosdepositispoorlyknown,totheextentthateven niobium (KravchenkoandPokrovsky, 1995).TheMorrodos The upperorehorizoncontainsmorethan12percent exploited. ThemostsignificantofthesearetheT are knownacrosstheworld,butnotcurrentlybeing Numerous othercarbonatite-hostedniobiumdeposits which iscurrentlybeingevaluated. carbonatite complexcontainsaniobium-tantalumdeposit same structurallineament,thenearbyCreviersyenite- is theonlyundergroundniobiummineinworld.On over 100metresbeneaththesurface,andNiobecmine (Belzile, 2009).Thesemineralisedzonesoccuratdepthsof long, withgradesof0.44–0.51percentniobiumoxide 50–150 is particularlyabundantinmineralisedlensesthatare plex. Itisdisseminatedthroughoutthecarbonatite,but is themainniobiummineralinSaint-Honorécom- nepheline-syenites, withacentralstock age Tomtor alkalinecomplexcomprisesanouterringof deposit inBrazil(Pollard,1995).TheNeoproterozoic- deposit inSiberia,RussiaandtheMorrodosSeisLagos

Permian: aunitofgeological timebetween299and251million yearsago. Placer deposit:aconcentration ofheavymineralstransported anddeposited Stock: asmallbodyofigneousrock,emplaced beneaththeEarth’s surface, Palaeozoic: aunitofgeologicaltimebetween 542and251millionyearsago.

metres wideanduptoapproximately750 23 limestones.Pyrochlore 26 sedimentaryrocks. 24 ofcarbonatite, 25 formedinan omtor may alsobeformedinpost-collisional plate settingssuchaszonesofcontinentalrifting,butthey Strength Elements Several factorscontributetotheenrichmentofHighField tantalum. rare earthelements,butarelesscommonlyenrichedin high contentsofzirconium,yttrium(Y),niobiumandthe Mineral depositsinalkalineigneousrockstypicallycontain but lowniobiumandtantalum(Pollard,1989,Küster, 2009). rubidium (Rb),uranium,thoriumandrareearthelements by highcontentsofiron(Fe),fluorine,niobium,zirconium, such asalkaligranitesandsyenites,arecharacterised environments. Themostevolvedalkalineigneousrocks, tal collisionevent(orogeny). many otherelements toformcompounds)thatareincompatible (seefootnote34). Lueshe syenite-carbonatitecomplex,whichisCambrian of Congo),Oka(Quebec,Canada),andSökli().The well-studied examplesfromLueshe(DemocraticRepublic 33 32 31 30 29 28 27 for niobium.TheCretaceous zon whichisenrichedinpyrochlore,andhasbeenmined weathering ofthecarbonatiteshasformedalateritehori- carbonatite(NasraouiandBilal,2000).Intense ameter, borderedbyaringdykeofcalcitecarbonatiteand in age, has a central core of syenite some 800 metres in di- Al in whichthemolecularamountofNa boles, oralkalipyroxenes).Peralkalinerocksareasubset potassium-rich minerals(feldspathoids,alkaliamphi- mineralogy, asthoserockscontainingcertainsodium-or The alkalineigneousrocksareclassified,onthebasisof Alkaline toperalkalinegranitesandsyenites sedimentary hostrocks(Yang etal.,2009). formed bytheinteractionofcarbonatite-derivedfluidsand sociated withcarbonatitemagmatismandmayhavebeen deposit inChina,whichisalsoenrichedniobium,as- (Lee etal.,2006).ThemajorBayanOborareearthelement abundant pyrochloreintheyoungerunitsofcomplex tised ultramaficrocks,carbonatitesandphoscorites,with of about20squarekilometres,andcomprisesmetasoma- atite-phoscorite complexisDevonian groups (ZurevinskiandMitchell,2004).TheSöklicarbon- containing mineralsoftheperovskiteandpyrochlore It includesthreeseparateniobium-mineraliseddeposits ing carbonatitesandfeldspathoid-bearingsilicaterocks. an elongatepluton,aboutsevenkilometreslong,compris-

High field strength elements: Elements of high valency (able to combine with High fieldstrengthelements: Elementsofhighvalency(able to combinewith Post-orogenic: post-datingalltectonicprocesses associatedwithacontinen- Post-collisional: post-datingthepeakof continental collision. Na Devonian: aunitofgeologicaltimebetween 416and359millionyearsago. Cretaceous: aunitofgeologicaltimebetween 145and65millionyearsago. Cambrian: aunitofgeologicaltimebetween 542and488millionyearsago. 2 O 2 3 O, K 30 . Alkalinerocksaremostcommonlyfoundinintra- 2 O andAl 2 O 3 : sodiumoxide,potassiumoxideandaluminium . 33 (HFSE),suchasniobiumandzirco- 28 Okacarbonatitecomplexis www.MineralsUK.com 2 29 O +K 31 inage,withanarea topost-orogenic 2 O exceeds 27 32

5 Niobium–tantalum their formation.TheHFSEareincompatible years ago. rather thanintoearly-formingcrystalsof solidminerals. both theEarth’ lithospheric considered tobederivedfromtheenrichedsub-continental and syenites.Alkalinemagmasaremostcommonly nium, inalkalineigneousrockssuchasgranites 37 36 35 34 the subjectofanongoingexplorationprogramme. tion intheMotzfeldtintrusion(Steenfelt,1991)whichis also hosttheniobium-tantalum-REEpyrochloremineralisa- mineralisation. Zonesofhydrothermallyalteredsyenite and theircountryrockscontainsignificanturanium-niobium Ilímaussaq Complex,hydrothermalveinsinthesyenites and Williams-Jones,2005).IntheKvanefjeldareaof these layersis0.1weightpercentniobiumoxide(Salvi niobium andtheREE.Theaveragegradeofin in eudialyte,withhighcontentsofzirconium,yttrium, which containstwenty-nineseparatelayersthatarerich occur inaunitoflayeredsyenitesknownaskakortokites, (Larsen andSorensen,1987).Themainmineraldeposits alkaline graniteswhicharespectacularlylayeredinplaces comprises arangeofmineralogicallyuniquesyenitesand Complex iselliptical,8x17kilometresatthesurface,and Ilímaussaq andMotzfeldtcomplexes.The Igneous Provinceinsouth-westGreenland,includingthe HFSE andREEthroughhydrothermal undergone furtherconcentrationofelementssuchasthe rocks, suchastheMotzfeldtdepositinGreenland,have land. However, manymineraliseddepositswithinalkaline way isintheIlímaussaqComplexofsouth-westGreen- most famousexampleofaniobiumdepositformedinthis be accumulatedthroughcrystalsettlingintolayers.The HFSE typicallyformrelativelydenseminerals,whichmay and syenites.Furtherconcentrationcanoccurbecausethe found disseminatedthroughouthighlyevolvedgranites syenitic ;insomelocalities,oremineralsare they becomeenrichedinthemostevolved,graniticand major areaofinterestliesintheMesoproterozoic although explorationisunderwayinsomeareas.One mines operatinginalkalinegraniteandsyenitecomplexes, At thetimeofwriting,therearefewniobiumortantalum Jones, 2005). dioxide (Goodenoughetal.,2000,SalviandWilliams- that areenrichedinfluorine,chlorine(Cl)and/orcarbon highly mobileinfluidsassociatedwithperalkalinemagmas Williams-Jones, 2005).TheHFSEandREEappeartobe

Mesoproterozoic: aunit ofgeologicaltimebetween1600and 1000million Hydrothermal: formed fromhotwater-rich fluids. Incompatible elements:arethosethat concentratedintomoltenmagmas, Lithospheric: thelithosphereisouter, rigidlayeroftheEarth,including s crustandtheuppermostpartofmantle. 34 mantle,andareenrichedintheHFSEfrom 36 processes(Salviand 35 andthus 37 Gardar of secondaryHFSE-bearingminerals,includinggittinsite mineral, haematite. tisation zone wherethegranitehasundergoneextensivehaema- area ofabout36squarekilometres.Ithasacentralore pluton, whichisMesoproterozoicinage,outcropsoveran In easternCanada,theStrangeLakeperalkalinegranite the REE. rich syenitesthatareenrichedinzirconium,niobiumand (> 500squarekilometres)alkalinecomplexwitheudialyte- age PilanesbergComplexofSouthAfricaisanotherlarge (Salvi andWilliams-Jones,2005).TheMesoproterozoic- cent niobiumoxideand0.7weightpertantalum concentrates haveaveragegradesofeightweightper been minedonandoffformanyyears,theloparite are richineudialyte,lopariteandapatite.Loparitehas syenite massifcontainslayeredsyeniteswithlayersthat In Russia’s KolaPeninsula,theDevonian-ageLovozero 39 38 an elongatebodyofnephelinesyeniteover3.5 the Kanyikaniobium-tantalumdeposit,whichcomprises niobium oremineral.InMalawi,explorationisongoingat massif (Kovalenkoetal.,1995).Pyrochloreisthemain mally alteredlatephaseintrusionsofaperalkalinegranite zirconium-niobium-REE depositisformedbythehydrother- In Mongolia,theDevonian-ageKhaldzan-Buregtey to developthemforREE,niobiumandtantalum. currently ownedbyAvalon Rare MetalsInc,whichintends and Williams-Jones,2005).TheThorLakedepositsare average gradesupto0.4weightpercentniobium(Salvi hosting themajorityofniobiumandtantalum, tantalum andzirconium,withcolumbite-tantaliteminerals posits areenrichedinberyllium(Be),yttrium,REE,niobium, alised zones,knownastheThorLakedeposits.Thesede- granites withanumberofhydrothermallyalteredminer- Lake igneouscomplexcomprisessyenitesandperalkaline Northwest Territories, thePalaeoproterozoicBlatchford Jones, 2005,SalviandWilliams-Jones,2006).InCanada’s of 0.56weightpercentniobiumoxide(SalviandWilliams- and pyrochlore.Orefromthiszonehasanaveragegrade a Palaeoproterozoic-agealbite-rich peralkalinegraniteat niobium andtantalumareextracted alongwithtinfrom consistent throughoutthegranite (Küster, 2009).InBrazil, tion oftheseoremineralsappearstoberemarkably chiefly columbite-tantaliteandpyrochlore.Thedistribu- contains disseminatedtantalumandniobiumoreminerals, stockisabout800metresinsurfacediameterand veins (BGS,2009).InSaudiArabia,theGhurayyahalkaline tres longwithnumerousmineralised,pyrochlore-bearing

Gittinsite: Acalcium-zirconium-bearing silicatemineral. Haematisation: alteration associatedwiththeformationof ironoxide 38 andcalciummetasomatism,producingarange www.MineralsUK.com

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6 Niobium–tantalum large peraluminousleucogranitic the world.Theseintrusionstypicallytakeformofa this typearethemainhostsfortantalumdepositsacross zones ofcontinentalcollision.Granitesandpegmatites most commonlyemplacedaspost-orogenicplutonsin formed bymeltingofpre-existingcrustalrocks,andwere than niobium)(C beryllium, (Sn),tantalumandniobium(tantalumgreater type offeldspar. oxide. lar (calciumoxide+sodiumpotassium oxide)islessthanmolecular peraluminous Granites andpegmatitesoftheLCTfamilyaretypically in lithium,caesium,tantalum) Granites andpegmatitesoftheLCTfamily(enriched Morocco, Nigeria,andNamibia. tantalum depositsoccurinmanyothercountries,including peralkaline intrusions with the potential for niobium and/or the Pitingamine(Bastos-Netoetal.,2009).Alkalineto 43 42 41 40 stage alteration,suchaskaolinisation Many ofthepegmatiteshavebeenhighlyaffectedbylate- (tin oxide)isalsoanimportantoremineralinsomebodies. microlite, ixioliteandwodginite.Tantalum-rich the mostimportantaregenerallycolumbite-tantalite, types cancontainarangeoftantalumminerals,which pegmatites fallingintothefirstthreetypesarezoned.All type; andthealbitetype(C type; thecomplexlepidolitealbite-spodumene type;thecomplex(spodumene-petalite-amblygonite) swarms. LCTpegmatitescanbedividedintofivetypes:the Many ofthelargesttantalumdepositsoccurinpegmatite and Cuney, 2005). trated intheuppermostpartsofgraniticbody(Linnen disseminated tantalumoreminerals,particularlyconcen- alteration bylate-stagefluids.Thesegranitesmaycontain , althoughproductionfromtheseminesceased has comefromtheGreenbushesandWodgina minesin In recentyears,muchoftheworld’s productionoftantalum heterogeneous, showingextensivealbitisation muscovite, topazandtourmaline,aretypicallyrather The granitebodiescontainmineralssuchasbiotite, sociated withexposedgraniticplutons. although insomeareasswarmsofpegmatitesarenotas- at thegreatestdistancefromgranite(C halo ofpegmatites,withthemostmineralisedpegmatites

Kaolinisation: alteration ofrockstoproducekaolin,alsoknown aschinaclay. Albitisation: alteration byfluidstoproducethesodium-rich mineral, albite,a Leucogranitic: alight-coloured,silica-rich typeofgranite. Peraluminous: achemicaltermusedforrocks inwhichthetotalmolecu- 40 andenrichedinlithium,rubidium,caesium, ˇ erný andErcit,2005).Thesemagmasare ˇ erný, 1989).Manyofthe 41 plutonsurroundedbya 43 . ˇ erný, 1989), 42 and mineralised pegmatitesareknown fromtheSuperior Tanco .Inaddition,numerousothertantalum- 1989). Caesiumandlithiumarealsoproducedfromthe ing thatprocessingofTanco isratherdifficult(C occur (14inall)andtheyaregenerallyfine-grained,mean- grade incertainzones.Awiderangeoftantalumminerals als arefoundthroughout,thoughconcentratedathigher pegmatite type,andisstronglyzoned;tantalumoreminer- a room-and-pillarundergroundmine.Itisofthecomplex thick and1600metresalongstrike,whichisexploitedin forms ashallowlydippingsheet,uptoabout100metres the Earth’s crust, usuallyanepisodeofcontinentalcollision. (greater thanthreekilometrelong)syn-tectonic mine insouth-westernAustraliaishostedagiant Advanced Metals(previouslyTalison). TheGreenbushes between 2008and2011.BothminesareownedbyGlobal 46 45 44 complex-type pegmatitebodyofArchaean metavolcanic bearing BernicLakepegmatitegroup,whichintrudes owned byCabotCorporation.Itispartoftherare- tantalum mineralisationatTanco, inManitoba,Canada, An Archaeanpegmatitebodyalsoformsthehostfor pegmatites isextractedbyopenpitmining. (Sweetapple andCollins,2002).Tantalum fromthese dumene type,andwodginiteisthemaintantalummineral is formedbyaseriesofpegmatitesheetsalbite-spo- columbite andwodginite.AtMountCassiteritethedeposit tantalum mineral,togetherwithsomemanganese-rich of albite-type,withmanganese-richtantaliteasthemain Lode isadyke-likepegmatiteaboutonekilometrelong, erite tantalum-mineralisedpegmatites.TheWodgina Main which includestheWodgina Main LodeandMountCassit- important areahereistheWodgina pegmatitedistrict, include sometantalum-mineralisedexamples.Themost Archaean rocksofthePilbaraCraton,andmanythese a largenumberofpegmatiteswarmsoccurwithinthe pit andundergroundmining.Innorth-westernAustralia, Greenbushes pegmatitehasbeenexploitedbybothopen the maintantalummineral(Partingtonetal.,1995).The and laterhydrothermalmineralisation,wheremicroliteis and tapiolitesinfractureswithinearlysilicatephases; form inclusionsincassiteriteandtourmaline;tantalites formed mineralssuchaswodginiteandixiolite,which mineralisation arerecordedwithinthispegmatite:early- body (Partingtonetal.,1995).Threephasesoftantalum appear tobegeneticallyassociatedwithalargergranitic sociated withtinmineralisation.Thispegmatitedoesnot contains largeresourcesofbothtantalumandlithium,as-

Metavolcanic: metamorphosed volcanicrocks. Archaean: aunitofgeological timebetween3800and2500 million yearsago. Syn-tectonic: formedduringanepisodeof tectonicactivityanddeformationof 46 Archaeanrocks.TheTanco pegmatite www.MineralsUK.com 45 age,which 44 , zoned, ˇ erný, 7 Niobium–tantalum province, andtheyareconsideredtobeOrdovician intruded intotheProterozoicrocksofNampulaSub- pegmatites, ownedbyNoventaLtd.Thesepegmatitesare tion currentlyfocusedinthezonedMarropinoandMorrua been minedsince1926,withtantalumminingandexplora- contains numerousmineralisedpegmatiteswhichhave In ,theAltoLigonhaPegmatiteProvince Quemeneur, 1997). at Nazareno,intheMinasGeraisdistrict(Lagacheand for tantalum,niobiumandlithiumattheVolta Grandemine zoic , alarge(aboutonekilometrelong),zoned,Protero- Province ofOntarioandManitoba(Selwayetal.,2005).In 48 47 mineralised granitesandpegmatitesarealsofoundin (Graupner etal.,2010).Numerousexamplesoftantalum- are veryvariable betweendepositsandfigures givenareindicati Table 3 syenite Alkaline graniteand primary deposits Carbonatite-hosted C-yepgaieTantalum andlessernio- LCT-type pegmatite C-yegaieTantalum andlesser LCT-type granite secondary deposits Carbonatite-sourced eoi yeBifdsrpinTpclgae n ong Majorexamples Typical gradesandtonnage Briefdescription Deposit type

Ordovician: aunitofgeologicaltimebetween488and443millionyearsago. Proterozoic: aunitofgeologicaltimebetween2500and542millionyearsago. 47 pegmatitebodyofalbite-spodumenetypeismined

Key characteristics andexamplesofthemajor typesof niobium andtantalumdeposits (gradesandtonnages or hydrothermalprocesses concentrated bymagmatic rocks. Oremineralsmaybe with silicicalkalineigneous lum depositsassociated Niobium andlessertanta- provinces rocks inalkalineigneous within carbonatiticigneous Niobium depositsfound (Li-Cs-Ta-enriched) type with pegmatitesofLCT bium depositsassociated altered are oftenhydrothermally leucogranitic plutons,which ated withperaluminous niobium depositsassoci- trated ore mineralsareconcen- intrusions inwhichniobium sions abovecarbonatite ing orsedimentarysucces- Zones ofintenseweather- 48 inage at gradesof0.1to1%Nb Generally <100milliontonnes, at 0.59%Nb reserves: 23.5milliontonnes Niobec, proven&probable at gradesof<0.05%Ta Generally <100milliontonnes, at gradesof<0.05%Ta Generally <100milliontonnes, 3% Nb < 1000milliontonnesatupto known deposit atTomtor, tonnagenot Up to12%Nb and <0.1%Ta be magmaticinorigin(Küster, 2009). matic alteration,thetantalummineralsareconsideredto the granitesshowsignificantevidenceoflatermetaso- disseminated throughouttheseintrusions,andalthough rather thaninpegmatites.Columbite-tantalitemineralsare the mineralisationisfoundinstock-likegraniteintrusions, towards production.Thesedepositsareunusualinthat and Nuweibiprospectsarecurrentlybeingdeveloped tantalite minerals(Küster, 2009).InEgypt,theAbuDabbab complex-spodumene typewhichisminedforcolumbite- Pegmatite, aCambrian-agedyke-likezonedpegmatiteof tres, buttantalumminingisfocusedontheMainKenticha whole hasanareaofapproximately2500squarekilome- granites inEgypt.AtKenticha,thepegmatitefieldasa pegmatites ofSomalia,andtheAbuDabbabNuweibi the KentichapegmatitefieldinEthiopia,Majahayan the Arabian-NubianShield(Küster, 2009).Theseinclude North Africa,intrudedintotheNeoproterozoicrocksof ve only). 2 O 5 inlateriticdeposits. 2 O 2 2 O 5 O

5 5 inplacer

2 2 O O 2 5 5 O 5

Congo Democratic Republicof Tomtor, Russia;Lueshe, Araxá andCatala˘o, Brazil; Marropino, Mozambique ticha, ;Morrua& Volta Grande,Brazil; Ken- Australia; Tanco, Canada; Greenbushes andWodgina, ; Yichun, Abu DabbabandNuweibi, Arabia; Kanyika,Malawi Brazil; Ghurayyah,Saudi Lake, Canada;Pitinga, sia; ThorLakeandStrange ; Lovozero,Rus- Motzfeldt andIlímaussaq, Canada Niobec, Canada;Oka, www.MineralsUK.com 8 Niobium–tantalum www.MineralsUK.com

Figure 3 Map showing the global distribution of niobium and tantalum mines, deposits and major occurrences. 9 Niobium–tantalum reprocessed toproducetantalum. from secondaryplacerdeposits.Thetinslagsarebeing weathered tin-mineralisedgranitesandpegmatites, andsouth-westernThailand,tinisproducedfrom have beenminedforcolumbite-tantaliteinthepast.In China) andtheNanpingpegmatites(south-eastern Elsewhere inChina,theAltaipegmatites(north-western rich cassiterite,andminormicrolite(Yin etal.,1995). in theformofdisseminatedcolumbite-tantalite,tantalum- lepidolite granite,whichcontainstantalummineralisation most partofthisbatholithisahighlyfractionatedtopaz- kilometres) graniticbatholithofJurassicage.Theupper- deposit, whichishostedinasmall(lessthan10square ites andpegmatites.ThemostwellknownistheYichun Several regionsofChinahavetantalum-mineralisedgran- deposits derivedfromthepegmatites. deeply weatheredpegmatitesandfromsecondaryplacer 1995). Columbite-tantalitemineralsareminedbothfrom the DemocraticRepublicofCongo(RomerandLehmann, belt whichextendsthroughBurundi,,Ugandaand mineralised pegmatitescutstheMesoproterozoicKibaran In CentralAfrica,azoneofNeoproterozoic-agetantalum- can bepoorlyconsolidated, andonlyrequire drillingand involving scrapers,bulldozers andloaders.Placerdeposits Land-based placerdepositsare amenabletostripmining are alsominedusingopen-pit methods. ore bodies,suchastheAraxá carbonatitedepositinBrazil, tres butseldomexceeds100metres.Heavilyweathered Open-pit miningmayreachdepthsofseveralhundredme- by truckorconveyorbeltforstockpilingpriortoprocessing. digging orblastingtheore,followedbyremovalofore Open-pit methodscommonlyinvolveremovingoverburden, ore bodiesareamenabletoopen-pitminingtechniques. Massive, orsteeply-dipping,low-gradenear-surface Surface artisanal andsmallscalemining(ASM). amounts ofniobiumandtantalumarealsoextractedby underground) mining,oracombinationofboth.Significant extraction aresurface(oropen-pit)andsub-surface and depthoftheorebody. Themostcommonmethodsof mineral; thetonnageandgrade;shape,geometry include: thephysicalandchemicalpropertiesofore rence. Factorsthatdictatetheselectionofminingmethods tantalum aresimilartoothermetalsofcomparableoccur- The miningmethodsemployedtoextractniobiumand Extraction Extraction methodsandprocessing reduction grade smelterwastescanbeupgradedbyelectrothermic although exceptionallythismayriseto30percent.Low- typically containseightto10percenttantalumoxide, decline and isaccessedviaa60-metreshaft20-degree Manitoba, Canada.ThemineislocatedunderBernicLake pillar miningmethodswereusedattheTanco pegmatitein conveyor ordumptrucktotheprocessingplant.Roomand roof support.Oreisblastedandthentransportedbyrail, per centtantalumandniobiumoxides(Roethe,1989). around 14 per cent. Tantalum is extracted from cassiterite However, thepercentageismuchhigherfor tantalumat for lessthantwopercentoftotalglobalniobiumproduction. of tinsmelterwaste.Niobiumproducedinthiswayaccounts Niobium andtantalumcanalsobeextractedasaby-product By-product production placer middlings and electrostatic furnace, utilisingcalcium oxide,ironoxideandcarbonasreducing agents. field. minerals usingmagneticforce. the formofaspiralramp. 55 54 53 52 51 50 49 ous stopes progresses inahorizontaldirectionbydevelopingnumer- pillar isanundergroundminingtechniquewhere tion, geo-technicalsupportandorehandling.Room development includingshaftsinking,de-watering,ventila- Underground operationscommonlyrequireextensivemine large, open-pitminingmethodsbecomeuneconomic. waste tooreratio,orstripratio.Oncetheratiobecomes factor inthedecisiontouseundergroundmethodsis example ifthedepositbecomestoodeep.Anothermajor surface methodsare,orbecomeprohibitivelyexpensive,for Underground miningmethodsareusuallyemployedwhen Underground mining less thanthoseforundergroundoperations. Capital andoperatingcostsforopen-pittechniquesarefar blasting techniques. tions, suchasWodgina Mine,areminedusingdrillingand simple strippingmethods,whilsthard-rocksurfaceopera- example, tin-tantalumplacersinMalaysiaareminedusing blasting wherematerialshavebecomecemented.For

Electrothermic reduction: areductionreactionperformedin an electricarc Electrostatic separation:theselectivesorting oforemineralsusinganelectric Magnetic separation:theselectivesorting ofmagneticallysusceptibleore Middlings: particlesofintermediategrade andsize. Cassiterite: tinoxideoremineral,SnO Decline: amineentrancewhichisneitherhorizontalnorvertical;oftenittakes Stope: thevoidcreatedbyextractingore. 50 fromthesurface(Cabot,2001). 55 49 yieldingasyntheticconcentratewithupto50 , orrooms,leavingpillarsofmaterialfor 52 54 usingshakingtables,andmagnetic separationmethods.Tin smelterwaste 2 . www.MineralsUK.com 53

51

10 Niobium–tantalum

ORE TYPE

Pyrochlore Tantalite e.g. Niobec Mine e.g. Greenbushes Mine

Crushing, milling and Undersize material screening stages to tailings Coarse desliming Fine desliming Coarse and fine gravity separation using shaking Coarse carbonate Fine carbonate tables, jigs and spirals flotation flotation Concentrate de-watering using cyclones and filter bed Desliming Slimes

Concentrate drying Low intensity magnetic separation Concentrate (4-6% Ta2O5)

Diamine collector Pyrochlore flotation Tailings High intensity magnetic Non-magnetic separation fraction to tailings Xanthates Sulphide flotation Sulphides

Magnetic fraction roasted Antimony and

www.MineralsUK.com Hydrochloric Concentrate minor sulphides to tailings

Concentrate (54% Nb2O5) Concentrate (20-30% Ta2O5)

Figure 4 Generalised beneficiation flow diagrams, based upon the Niobec and Greenbushes operations. 11 Niobium–tantalum froth flotationusingdiaminecollectors sought-after pyrochloreiscollectedfromtheslurryby intensity magneticseparation,andsenttowaste.The stage. Magnetiteisremovedfromtheslurry, bylow of frothflotation,followedbyanadditionaldesliming metal . ing. mineral . minerals fromhydrophilic(water variations inmineraldensity. Screw) are removedfromaslurrybyseriesofrotatingrakes(similartoanArchimedes ity separation oxide usinganumberofmethodsinmultiplestages:grav- rock isfurtherconcentratedtoaround54percentniobium mineral particles.Theslurrycontainingniobiumandwaste desliming and classified,afterwhichtheresultantslurryissentfor At theNiobecoperationinCanadaniobiumoreisscreened the physicalandchemicalcharacteristicsofore. tantalum orefromgangue crushing theorefollowedbyseparationofniobiumand mally undertakenat,orcloseto,theminesiteandinvolves niobium andtantalumcontents.Initialconcentrationisnor- After miningtheoresareprocessedtoincreasetheir Processing 62 61 60 59 58 57 56 upon thecharacteristicsofore. and magneticseparationtechniques,againdepending 30 percenttantalumoxideusingpredominantlygravity tantalum andwastematerialisconcentratedtoaround liberate tantalummineralparticles.Theslurrycontaining niobium ;theyarecrushed,milledandscreenedto Tantalum oresareinitiallytreatedinasimilarmannerto niobium oxide(Figure4)(Iamgold,2009). ing afinalconcentratethatcontainsaround54percent Residual impuritiesareleachedbyhydrochloricacid,leav- froth flotationisusedtoremovesulphides,suchaspyrite. vibrating screensandscrewclassifiers and milledinrodorballmillsoperatingclosedcircuitswith Niobium oreisfirstcrushedinjaw, coneorimpact Ore beneficiation ent processingroute. tantalum aregeochemicallysimilareachrequiresadiffer- of physicalandchemicalmethods.Althoughniobium separation, andacidleaching

Diamine collectors:a positivelychargedcationiccollectorused tofloatrare- Desliming: theremovalofparticlesin micronsizerangepriortoprocess- Acid leaching:theprocessofextractingmetal fromaconcentrateusing :theselectiveseparation of hydrophobic(water-repelling) ore Gravity separation:theselectivesortingoforemineralsbyexploitingnatural Screw classifiers:awetgravityseparationmethodinwhichdenseparticles Gangue: wastematerialassociatedwithoreminerals. 61 . Carbonatematerialisremovedbytwostages 58 , frothflotation -attracting) oreminerals. 56 material,usingacombination 60 59 may be used, depending on maybeused,dependingon , magnetic and electrostatic , magneticandelectrostatic 57 to liberate niobium toliberateniobium 62 . Afinalstageof of potassiumtantalumfluoride(K mixed organicsolventsolutionresultsinthecrystallisation metal production.Theadditionofpotassiumfluoridetothe bides. Niobiumoxideisalsothestartingpointforniobium temperature isusedtoproduceniobiumandtantalumcar- separation isusedtoseparatetheparamagnetic to sixpercenttantalumoxide.Highintensitymagnetic producing atantalumconcentratecontainingaboutfour powders withoutmelting. water). tion, phasetransitionsortheremovalof volatile matter(e.g.carbondioxideand externally appliedmagneticfield. of furnace toformniobiumandtantalumoxides.Theprocess and jigs are processedusingacircuitofshakingtables,spirals At theGreenbushesmineinAustraliatin-tantalumores 66 65 64 63 sulphuric and tantalumcanbeextractedfromthehydrofluoric- ion exchange,toseparateniobiumfromtantalum.Niobium liquid separationmethods,involvingsolventextractionor tantalum-bearing acidsolutionisthentreatedusingliquid- mixture ofhydrofluoricandsulphuricacids.Theniobium- A mixedniobium-tantalumconcentrateisdigestedusinga main methods. reduced toformpuremetalsandmetalpowdersbytwo (Albrecht, 1989).Thetantalumandniobiumcompoundsare different compounds Tantalum andniobiummetalcanbeproducedfromthree Conversion tometal separate tantalumfromtin(Figure4)(Fetherston,2004). flotation androastingtoremovesulphides,smelting fraction isfurtherprocessedusingacombinationoffroth 30 percenttantalumoxidebyroasting.Thenon-magnetic paramagnetic fractionisfurtherconcentratedtoaround lum grainsfromthenon-magnetictin-tantalumgrains; for tantalummetalproduction(Figure5). monia (NH the mixedorganicsolventsolutionbyadditionofam- Niobium andtantalumareprecipitatedashydroxidesfrom ant inkerosene. tantalum andisusuallyperformedusinganamineextract- is usedtoproducehigh-puritysolutionsofniobiumand , ,tinandtitanium(Figure5).Ionexchange ketone (MIBK),whilstleavingbehindimpuritiessuchas , tributylphosphate(TBP)ormethylisobutyl

Sintering: aprocess of formingacoherentbondedmassbyheating metal Calcined: athermalprocessappliedtoores inordertobringaboutdecomposi- Paramagnetic: aformofmagnetismthat onlyoccursinthepresenceofan Shaking tables,spiralsandjigs:water gravitybasedseparationdevices. 63

. Theroughconcentrateisde-wateredanddried acid mixturebyusingorganicsolvents,suchas 3 ). Theresultanthydroxidesarecalcined 66 theoxideproducts,withcarbon,athigh

—

, oxidesandchlorides www.MineralsUK.com 2 TaF 7 ), thepre-requisite 64 tanta- 65 ina 12 Niobium–tantalum utilising high-energy electronbeamsasaheatsource. and ironoxideasreducing agents. beam melting purification isachievedbyvacuum arcfurnaceorelectron tantalum vesselsunderlow-oxygenconditions.Further ics industry, theconversionprocessisperformedusing ensure ahighdegreeofpurity, asrequiredbytheelectron- metal powder, potassiumfluorideandsodiumfluoride. To then roastedinacontinuousfurnacetoproducetantalum liquid sodiumandinertsaltstoformapaste.Thepasteis talum metal.Potassiumtantalumfluorideisblendedwith with sodiumisthemostcommonmethodofproducingtan- The reductionofpotassiumtantalumfluoridebyreaction added tothemixturepriorreduction(Albrecht,1989). containing about60percentniobium,ironoxidepowderis to increasethepurityofniobium.To produceferro-niobium, lime andfluorspar. Electronbeammelting is commonlyused 68 67 mic reduction um. High-purityniobiummetalisproducedbyaluminother niobium metalandtheotherisusedtoproduceferro-niobi- production ofniobiummetal:oneisusedtoproducepure Two slightlydifferentproductionroutesareavailableforthe Figure 5

(MIBK) Tributylor Phosphate (NH Ammonia Electron beammelting: ahigh-temperature(700-1000°C)vacuum furnace, Aluminothermic reduction:anexothermic reactioninvolvingaluminiumoxide aluminothermic reac aluminothermic to formmetalto niobium precipitate niobiumas precipitate (TBP) organic(TBP) niobium(Nb oxide Niobium hydroxide is Niobium hydroxide Nb Nb-hydroxide Nb-hydroxide calcined to form to calcined 2 O

5

added

is reducedis by Chemical processingofniobiumandtantalumconcentrates. 3 ) is added)is to 67 68 of high-purity niobium oxide with aluminium, ofhigh-purityniobiumoxidewithaluminium, oftantalumpowder(Albrecht, 1989).

2 ti O on 5 )

with hydro the acid solu Nb and Ta are from extracted MixedNb-Ta concentrate Sintering oxide powders Sintering Chemical decomposi temperature produces temperature Nb-andTa- Nb-Ta mixedsolu Nb-Ta with at high with ti Filtra extrac fl uoric and sulphuric

ti acid on using ti on on on

ti on ti

on

- Ammonia (NH Ammonia calcined to formto tantalumcalcined 69 Lezhnev (©EnoughProject) Figure 6 Artisanal miningofcoltan provide alivelihoodforover100 millionpeopleworldwide Artisanal andsmallscalemining (ASM)isbelievedto extracted byartisanalandsmall scalemining(ASM). cessed conventionally, significantamountsarealso Although niobiumandtantalumareextractedpro- Residue to waste or recycle

Iron and Tantalum is hydroxide Tantalum precipitate tantalum tantalum as precipitate Image takenbySasha Lezhnev. ©EnoughProject.Used withPermission. raffi oxide (Ta oxide Ta-hydroxide Ta-hydroxide nate to waste ti

tanium-bearing 3 (columbite-tantalite).Source:Sasha 2 ) is added)is to O 5 )

69 (K adding potassium fl potassium adding

. fl Potassium-tantalum- 2 with moltenform to with Ta TaF www.MineralsUK.com 2 O 7 is directly crystallised directlyby ) crystallised is 5

tantalum metal tantalum extract solu extract is reduced by reac reduced by is uoridethe to ti on

uoride

ti on 13 Niobium–tantalum addition some large electronicscompanies arenow the problemsofASMandconflict mineraltrading.In charities haveinitiatedschemes aimedatalleviating Many non-governmentalorganisations (NGOs)and tronic goodssuchasmobilephones (Figure7). may beexportedtoAsiaforinclusioninconsumerelec- components suchascapacitors.Finallythese then beshippedtothewesternworldforuseinelectrical the sourceoforiginalore.Theprocessedmaterialmay and smelting.Onceprocesseditisimpossibletodetermine orUgandamaybeshippedtoAsiaforprocessing tronic productsthroughouttheworld.OrefromRwanda, Illegally tradedcoltanoremayendupinconsumerelec- ing (Bunting,2010). excess of$1billionin2009throughconflictmineraltrad- It isestimatedthatrebelgroupsintheDRCmade bouring countriessuchasRwanda,BurundiandUganda. the majorityofcoltanminedinDRCendsupneigh- quantity ofcoltanminedandexported.Itisbelievedthat Consequently itisdifficulttoaccuratelycalculatethe pegmatite sources,islabourintensiveandunregulated. small scaleminingofcoltan,fromeitheralluvialor global tantalumproductionwasfromAfrica.IntheDRC (DRC). Itisestimatedthatin2009over50percentof Africa, inparticulartheDemocraticRepublicofCongo Coltan isfoundinsignificantquantitiespartsofcentral ends andtofinancefurtherfighting. from thesaleofconflictmineralstofurthertheirown is oftenorganisedbyarmedgroupswhousetheprofits given risetotheterm‘conflictminerals’.Theirillicitmining The miningofthesemineralsundersuchconditionshas conditions ofarmedconflictandhumanrightsviolations. significant quantitiesbyASM,cansometimesbeminedin bite-tantalite (coltan)(Figure6),whichareproducedin Certain minerals,suchasgold,tin,tungstenandcolum- (Hentschel etal.,2003). ties fallingoutsidethehostcountries’legalframework Additionally, ASMisoftenunregulatedwithmany activi ▪ ▪ ▪ ▪ ▪ characterised by: but capital-,mechanisation-andtechnology-poor. ASMis and isdefinedasminingactivitiesthatarelabour-intensive ▪ ▪ ▪ ▪ ▪ Insufficient considerationofenvironmentalissues Low salaries Inefficiency inextractionandprocessing Poorly qualifiedandtrainedpersonnel Poor occupationalsafety - Figure 7 (Bunting, 2010). monitor exports,controlitsarmy andcombatrebelforces also reliesontheabilityofcountries liketheDRCto reasons explainedabove.The successoftheseschemes completely avoidtheuseofthese componentsforthe their products.However, itislikelytoprovedifficult refusing touseconflictmineral-bearingcomponentsin chain. Source:(EnoughProject,2011).

shipped tothewestern to Asiamanufacture electrical components consumer Small scale Small miningof coltan inDemocratic Asia forsmelting and Components shipped conversion tometal Rwanda, Ugandaor Mobilephones, MP3 Processed material Europe andthe USA such ascapacitors Republic ofCongo players, laptopsand Ore is transported Ore cameras aresoldin circuit boardsand world toproduce

to neighbouring Ore shippedto Ore An exampleofaconflictmineralsupply Burundi

ore electrical components electrical consumer goods consumer processed material processed ore

www.MineralsUK.com 14 Niobium–tantalum other niobiumcompounds,suchaschloride(NbCl purity. Itisgenerallythestartingpointforproduction of produced indifferentgradesatbetterthan99percent (Nb of forms,themostsignificantwhichare: Niobium andtantalumareutilisedtradedinavariety Specifications Specifications andUses 70 agent. tantalum (TaC) andlithiumtantalate(LiTaO niobium carbide(NbC)andlithiumniobate(LiNbO metal includecarbothermicreduction at around800°C.Othermethods ofproducingtantalum reduction ofpotassiumtantalum fluoridesaltsbysodium Tantalum metalandpowder isformedbythe tantalum byweight. brown metallicpowdercontaininginexcessof90percent in afurnace.Theresultingtantalumcarbideisheavy, sintering fine-grainedtantalumpowderwithexcesscarbon hardness 9-10)refractoryceramiccompound,formedby (TaC) isanextremelyhard(Mohs (Ta solvent extraction. sium fluoridewiththetantalum-bearingextractantfrom tantalum metalpowderandisproducedbyreactingpotas- Potassium tantalumfluoride(K beam orvacuumarcfurnacemelting. mic reaction.Furtherpurificationisachievedbyelectron pentoxide, ironoxideandaluminiumbyaluminother- niobium andisproducedbyreducingamixtureof Ferro-niobium (60%Nb)containsabout60-70percent further purificationachievedbyelectronbeammelting. pentoxidewith by thealuminothermicreductionofniobium Niobium metalandpowder 87 percentniobium. a heavy, brown-greymetallicpowdercontaining around carbon andheatingtoaround1800°C.Niobiumcarbideis mixture offinely-groundniobiumpowderwithanexcess 8.5-9) refractoryceramiccompound,formedbysinteringa Niobium carbide(NbC)isaveryhard(Mohshardness tantalum compoundsincludingchloride(TaCl

Carbothermic reduction: anexothermicreactioninvolvingcarbon asareducing 2 2 O O 5 5 ) ) isthestartingpointforother is a colourless, unreactive isacolourless,unreactivesolid 2 TaF is most commonly formed is mostcommonlyformed 7 ) istheprecursorto 70 oftantalum 3 ). ). 3 ). 5 ), 5 ), ), harmony withtissue withoutcausingdamagingchanges. cold-formed shape;returningtothepre-deformed shapeuponheating. temperature. to mechanicalstrain. the puremetal. ing thesameperiodoftime(Figure9). carbides andcapacitor-grade powdershasdecreaseddur- between2004and2010.Theproductionofboth and metalproductsallrepresentgrowthareasduringthe Metallurgical gradepowders,chemicals,tantalumingots carbides makeuptheremaining41percentofend-uses. for about48percent.Tantalum metalproducts,ingotand sources suggestthatcapacitor-grade powder mayaccount end-use oftantalumatabout24percent.Althoughsome while is usedinthemanufactureofmetallurgicalgradepowders to manufacturetantalumchemicals.Afurther17 In 2010almost18percentoftantalumproductionisused niobium hasdecreased(Figure8). production ofniobiummetalproductsandhigh-purityferro- niobium chemicals and niobium alloys has increased whilst products. Between2004and2010theproductionofboth high-purity ferro-niobium,andotherniobiummetal ture ofniobiumalloys,chemicalsandcarbides, steels; theremaining11percentisusedinmanufac- to produceferro-niobium,usedinhighstrengthlowalloy About 89percentofglobalniobiumproductionisused ▪ ▪ ▪ ▪ ▪ ▪ plications (Table 4and5).Thesepropertiesinclude: vital componentsinadiverserangeofproductsandap- The uniquepropertiesofniobiumandtantalummakethem Uses pentoxide andelectrolysis 76 75 74 73 72 71 piezoelectric properties are colourless,crystallinesolidswithuniqueopticaland Lithium-niobate (LiNbO be achievedinthefinalproduct. electron beammethods,averyhighdegreeofpuritycan salts. Bydoubleortriplemelting,usingarc-furnace ▪ ▪ ▪ ▪ ▪ ▪

Bio-compatibility: the abilityofaprosthesisimplantedinthe bodytoexistin Co-efficient ofcapacitance: theabilityofasolidtostorean electrical charge. Shape memoryproperties:theabilityofan alloyto‘remember’itsoriginal Superconductivity: azeroelectricalresistance occursinsomematerialsatlow Piezoelectric: theaccumulationofelectrical chargeinamaterialresponse Electrolysis: amethodofreducingmetalsfrommetalliccompoundstoobtain bio-compatibility high coefficientofcapacitance shape memoryproperties very highmeltingtemperatures -resistance superconductivity -grade powderproductionisthelargest 76 73 3 72 ) andlithium-tantalate(LiTaO . 71 ofpotassiumtantalumfluoride 74 www.MineralsUK.com 75

per cent 3 ) 15 Niobium–tantalum other inresponseto a changeingrainshape. 77 boundary deformation dition ofniobiumtosteelincreases strength,reducesgrain production ofhighstrengthlow alloysteels(HSLA).Thead- alloys. Niobium,intheformof ferro-niobium, isusedinthe Niobium andtantalumarebothusedintheproductionof Steel andotheralloys 11%

17% Grain boundarydeformation: theprocessbywhichgrainsmay movepasteach NbTi; NbZr and NbCu) and NbZr NbTi; High-purity ferro-niobium High-purity (including alloys Niobium products metal Niobium 18% 15% 89.0% 42% 24% 2004 11.0% 2010 77 and reduces weight. HSLA steels are andreducesweight.HSLAsteels are 7% 9% 2004 4.0% 6% 12% 17% 22% (Schwela, 2010a). and 2010.Source: tantalum in2004 of end-uses Comparison Figure 9 powdermetal and tantalum powder tantalum Tantalum chemicals Tantalum grade Metallurgical grade Capacitor products metal Tantalum ingot Tantalum carbides Tantalum 0.9% (HSLA) carbides) (including Strength Low Steel LowAlloy Strength Ferro-niobium for High for Ferro-niobium chemicals Niobium 4.7%

1.4%

Vacuum gradeferro-niobium capable ofregainingtheirshapeonheatingto1120°C. Such alloyscanbebent,compressedordeformedbutare applications becauseoftheshapememoryproperties. Tantalum-ruthenium alloysareusedinanumberofmilitary such asmagneticresonanceimaging(MRI)scanners. ducting magnetsrequiredformedicalimagingequipment, niobium-tin alloyscanalsobeusedtoproducesupercon- processing equipmentandpipelines.Niobium-titanium corrosion resistantandareusedtomanufacturechemical zirconium, titaniumandtin.Thesealloysareextremely Other metalswhichareusedinalloyswithniobiuminclude joints andmedicaldevicessuchaspacemakers. with humantissueisutilisedintheproductionofprosthetic rust-free fastenings.Thebio-compatibilityoftantalum-alloys quired suchaschemicalprocessingequipment(Figure10)and is alsousedinapplicationswherecorrosionresistancere- C103 oxidation andcorrosion. strength andcreepresistance attemperaturesabove700°C, andresistanceto niobium oxideandvacuumarcfurnacemelting. making itthecathodeofanelectrochemical cell. 89 percentniobium.Tantalum superalloys,ReneN6 two and 8.5 per cent tantalum. Many superalloys contain two and8.5percenttantalum. Manysuperalloyscontain tions suchasgasturbineblades,typicallycontainbetween tion and oilgaspipelines.Theyalsoprovidecathodeprotec- used tomanufacturevehiclebodies,shiphulls,railwaytracks, 80 79 78 CSMX-10 718 stress applications.Examplesofniobiumsuperalloysinclude constituents ofsuperalloys

Superalloys: arehigh-performance alloysthathaveexceptional mechanical Vacuum gradeferro-niobium:ferro-niobiumproducedusinghigh-purity Cathode protection:atechniqueforreducing corrosionofametalsurfaceby 78 ® tolargesteelstructuressuchasoilplatforms.Tantalum , used in rocket thruster nozzles, which contains about , usedinrocketthrusternozzles,whichcontainsabout ® , usedinhigh-temperature,high-stressapplica- ® , which contains about five per cent niobium and , whichcontainsaboutfivepercentniobiumand 88.7% (Schwela, 2010a). of niobiumin2004and2010.Source: Figure 8 11.3%

Comparison ofend-uses 80 2010 usedinhigh-temperature,high- 79 and tantalum are important andtantalumareimportant www.MineralsUK.com 2.7% 2.5% 5.2% 0.9% ® and and 16 Niobium–tantalum manufacture ofchemicalprocessingequipment. Figure 10 83 82 81 the formofTaNbC temperature applications.Tantalum andniobiumcarbides,in substancesthatareoftenusedinhigh-stress,high- Niobium andtantalumcarbidesareextremelyhard,refractory Carbides chromium, aluminium,,titaniumandhafnium. nickel-iron; otherelementsalsousedinalloymixturesinclude appreciable amounts,upto50percent,ofnickel,,or Source: ©Corbis. Table 4 ealria uealy o e nie n ubn ldsVacuum-grade ferro-niobiumandvacuum-grade Superalloysforjetenginesandturbineblades Physics Metallurgical ,streetlightingsystemsandsurface Medicine Niobiumcarbide Cuttingtools,railwaytracksand shiphulls Electronics Architecturalsteelsandcathodeprotection Engineering Chemicalprocessingequipmentandoilgas Construction Chemicals surface Vehicle bodies and Usage Automotive Industry

WTiTaNbC: -titanium-tantalum-niobium-carbide. WTiTaC: tungsten-titanium-tantalum-carbide. TaNbC: tantalum-niobium-carbide.

Summary ofthe mainusesofniobiumbyindustry sector Tantalum andniobiumareusedinthe 81 , WTiTaC Particle physicsresearch mapping) and magnetoencephalography(brainactivity Superconducting magnetic coils in MRI scanners technologies acoustic wavefiltersforsensorandtouchscreen systems forlargesteelstructures pipelines lenses Ceramic capacitors,glasscoatingsandcamera 82 orWTiTaNbC 83 , may be added , maybeadded

purity (CVD), orphysicalvapourdeposition(PVD) plied tosurfacesusingeitherchemicalvapourdeposition Thin coatingsofniobiumortantalumcarbidemaybeap- cent titaniumcarbide,andninepercobaltbinder. ,10.5percenttantalumseven Such ahardmetalcompositemaycontain73.5percent metals arealsousedinhigh-speeddrillingandcuttingtools. strength andresistancetocorrosionabrasion,hard using acobaltornickelbinder. Onaccountoftheirveryhigh ite ofvariousmetalcarbidescementedintoacompactmass Cemented carbide,alsoknownashardmetal,isacompos- refractory coatingsinnuclearreactorsandfurnaces. and drillbitsfortheminingindustry. Carbidesare alsousedas speed cuttingandboringtools,teethforexcavatorbuckets to tungstencarbideinthemanufactureofindustrialhigh- 84 abrasion- andcorrosion-resistantcoatings,structural of productscontainingthesemetals,forexample,alloys, of applicationsandareoftentheprecursortoanumber Niobium andtantalumpowdersareusedinawiderange Powders resistance, increasingthelifeoftoolcuttingedges. Carbide coatingsoftenincreasestrengthandimprovewear

Vapour deposition:aprocessofthinfilmdepositionusedtomanufacturehigh- . Source:(TANB, 2011a). , high-performancesolidmaterials. Niobium-titanium alloyandniobium-tin alloy niobium nitride Niobium-, niobium-tinalloyand niobate Niobium powder, niobiumoxideandlithium HSLA ferro-niobium(60%Nb),niobiummetal and niobium-1%zirconiumalloy HSLA ferro-niobium(60%Nb),niobiummetal nickel-niobium Niobium oxide HSLA ferro-niobium(60%Nb) Niobium product www.MineralsUK.com 84 techniques. 17 Niobium–tantalum Table 5 heated orcooled. pounds withuniqueoptical,piezoelectricandpyroelectric Lithium niobateandlithiumtantalatearechemicalcom- for useincapacitorsandhigh-performancebearings. eyeglass lenses,niobium-andtantalum-dopedceramics amples includehighrefractiveindexglassforcameraand production ofspecialityglassandstructuralceramics.Ex- Niobium andtantalumoxidesarecommonlyusedinthe Chemicals than tantalum-basedcapacitors. but theyarecommonlylargerandhaveashorterlifespan Niobium powderisalsousedtomanufacturecapacitors powders formedium-voltage,medium-capacitanceuses. for low-voltage,high-capacitanceapplications;andflake powders forhigh-voltageapplications;nodular for capacitorproductionaremadeinthreeforms:angular mobile phonesin2010was417million.Tantalum powders capacitors (MBM,2006)andglobalproductionofnew because anaveragemobilephonecontains23tantalum capacitor isverysmallthisasignificantapplication an electricalcharge.Eventhoughthequantityusedineach the productionofcapacitorsbecauseitsabilitytohold ceramics. High-puritytantalumpowderisprimarilyusedin 85 iiayMissile parts,ignitionsystems,night vision Military Furnaceparts,superalloysforjetengines and Pace makers, hearingaidsandprosthetic Metallurgical Medicine Capacitors,surfaceacousticwavefiltersfor Cutting tools Electronics Engineering Cathodeprotectionsystemsforlargesteel Chemicalprocessingequipment Construction Chemicals surface coatings Anti-lock brakesystems,airbagactivation Ceramics and Usage Automotive Industry

Pyroelectric: theabilityofamaterialtogeneratetemporaryvoltagewhen

Summary ofthe mainusesoftantalumbyindustry sector goggles andGlobalPositioning Systems(GPS) rocket enginenozzles devices suchashipjoints drives, andLEDlights sensor andtouchscreentechnologies,harddisc bolts resistant fastenerssuchasscrews,andnuts structures suchasoilplatformsandcorrosion lenses andX-rayfilm Ceramic capacitors,glasscoatings,camera systems andenginemanagementmodules 85

current technology. been fullygeologicallyevaluatedandiscommerciallylegallyminableusing of amineralcommodity. of rockthatis,ormaybecome,potentialeconomicinterestfortheextraction primary reserves and resources of niobium and tantalum are primary reservesandresourcesofniobiumtantalumare for niobiumandtantalumarenotwelldocumented.However, Unlike manyothermetalsglobalresourceandreservedata Resources production World resources,reservesand transistors anddigitalcircuits. applications suchaslightemittingdiodes(LED),solarcells, is aneffectivesemi-conductorusedinnumerouselectronic ducting magnets,usedinMRIscanners. Niobium nitrideisanimportantcomponentofsupercon- used intouchscreentechnologies. devices, usedinrangefindingapplications.Theyarealso as mobilephones,motiondetectorsandlaserswitching acoustic wavefilters,whichareemployedindevicessuch electronic components,suchascapacitorsandsurface properties. Theyareprimarilyusedinthemanufactureof 87 86

Mineral reserves:amineralreserveisthepartofresourcewhichhas Mineral resources:amineralresourceisconcentrationofmineralsorbody . Source:(TANB, 2011b). Tantalum carbide Tantalum metal Tantalum product Tantalum ingotsandtantalumoxide Tantalum metalandtantalumingots Tantalum metal ingots andtantalumnitride ,tantalumpowder, tantalum Tantalum metal(sheets,rods,platesandwire) Tantalum oxideandyttriumtantalate Tantalum powder 86 andreserves www.MineralsUK.com 87 18 Niobium–tantalum Geological Survey Statistics database, British 2009. Source:World Mineral ore) between1997and niobium contentofmined production (basedonthe CBMM, 2011,Papp,2011a).T Table 6 ** OnlyincludesresourcesfromCatalão(AngloAmerican,2011) * Deemeduneconomicat2010prices(Papp,2011a) Figure 11 respectively, accordingtotheTantalum-Niobium International to beabout317000tonnesandalmost153 number ofcountriesthanthoseniobiumandareestimated Tantalum oreresourcesandreservesarelocatedinagreater Tantalum resourcesandreserves seven percentoccurinCanada(Table 6). over 93percentoccurringinBrazilandtheremaining estimated tobeintheregionof485milliontonneswith Global niobiumorereserves,provedandprobable,are niobium resourcesincludeEgypt,MalawiandGreenland. and Canada.However, othercountrieswith unquantified Niobium resourcesarealmostexclusivelylocatedinBrazil Niobium resourcesandreserves for theforeseeablefuture,atleastnext500years. estimated tobemorethansufficientmeetglobaldemand oreProvedandprobable Source ntdSae 150000* Canada Brazil Total

Estimated globalreservesandresourcesofniobiumore.(Iamgold, 2009,AngloAmerican,2011, Global niobium . reserves (tonnes) 5 0 0 11142740 452 200000 8 3 0 11322422 484 436000 32 086000 otal resourcesarenotreportedasallcountriesincluded. Tonnes Nb 120000 100000 80000 60000 40000 20000 0

1997 Contained Nb

1998 (tonnes) 179 682 ---- 1999 and refineryequipment.Demandforthesesteelsislinked HSLA, usedinthemanufactureofcars,buildings,ships niobium productionislinkedtogrowingconsumptionof the productionofcolumbiteandtin-slags.Theincreasein cent ofthetotal,withonlyminorproductioncomingfrom mineral pyrochlore,accountingforapproximately98per in 2009(Figure11).Theprimarysourceofniobiumisthe proximately 20000tonnesin1997toover100 World productionofniobiumrapidly increasedfromap- Niobium production Production East, Africa,NorthAmericaandEurope(Table 7). 60 percentoccurinAustralia,Asia,RussiaandtheMiddle resources atapproximately40percent.Theremaining Production (DNPM–Brazil).Brazilhasthelargestshareof Study CentreandtheNationalDepartmentofMineral 2 2000 O 5

2001 Inferred resources

2002 11 900000 37 912000 (tonnes) n.a. 2003 ----

2004 www.MineralsUK.com 2005

2006 Contained Nb 214 200** (tonnes) 219 889 n.a.

2007 ----

2008 2

O 5 2009 Source Most likely resource Percentage of Reserves (tonnes Ta) 88 base (tonnes Ta2O5) resources Brazil 129 274 40 87 360 Australia 65 771 21 40 560 China and Southeast Asia 33 112 10 7 800 Russia and Middle East 31 298 10 ---- 28 576 9 3 120 Other Africa 21 318 7 12 480 North America 5443 2 1 500* Europe 2268 1 ---- Total 317 060 100 152 820 *Deemed uneconomic at 2010 prices (Papp, 2011b)

Table 7 Estimated global tantalum reserves and resources. (Papp, 2011b, Schwela, 2010a, DNPM, 2009).

particularly to the recent industrial development of nations (such as used in the Large Hadron Collider), and cam- such as China and India, and the rapid growth of the global era lens coatings, superalloys and functional and structural population. For example, in 1997 annual car production ceramics. was around 53 million vehicles compared with nearly 62 million in 2009 (OICA, 2011). In 1997 Brazil accounted for approximately 88 per cent of world niobium production. This figure has since risen to The increased demand for niobium may also be attributed about 95 per cent. Canada is responsible for the majority to its use in mobile telephones, superconducting magnets, of remaining production (Figure 12).

100%

90%

80%

70%

60%

50%

40%

Percentage production Percentage 30%

20%

10% Figure 12 Global niobium production by country 0% between 1997 and 2009. 2001 2009

Source: World Mineral 2007 1998 1999 2000 2003 2004 2006 1997 2005 2008 2002 Statistics database, British Geological Survey. Brazil Canada Africa Niobium–tantalum

19 www.MineralsUK.com 20 Niobium–tantalum Geological Survey Statistics database, British Source: World Mineral between 1997and2009. production bycountry Figure 14 Geological Survey Statistics database,British 2009. Source:World Mineral ore) between1997and tantalum contentofmined production (basedonthe Figure 13 is avitalcomponentinwiderangeofconsumerproducts. tantalum isdrivenmainlybytheelectronicsindustrywhereit trates suchasstruveriteandcolumbite-tantalite.Demandfor remainder comesfromtin-slagmaterialandotherconcen- associated withtheprimaryoremineraltantalite,while 2009 (Figure13).Abouthalfofalltantalumproductionis tonnes; sincethenithasdeclinedtoabout900tonnesin Global tantalumproductionpeakedin2001atjustover2000 Tantalum production

Global tantalum Global tantalum . .

Percentage production Tonnes Ta 100% 1000 1500 2000 2500 10% 20% 30% 40% 50% 60% 70% 80% 90% 500 0% 0

1997 Australia Australia 1997

1998 1998

1999 1999

widespread althoughAfrica,predominantlyRwanda Unlike niobium,productionoftantalumismuchmore ume ofconflicttantalumenteringthemarketfromDRC. a resultoftheeconomicdownturn,andincreasedvol- and maintenanceduetothedropinpriceoftantalum,as mines, inAustralia.Theseoperationswereplacedoncare temporary closureofboththeWodgina andGreenbushes The recentdeclineintantalumproductionisrelatedtothe 2000 Malaysia Malaysia 2000

2001 2001

2002 2002

2003 2003 Brazil

2004 2004

www.MineralsUK.com 2005 2005 Canada

2006 2006

2007 2007

Africa 2008 2008

2009 2009 and Democratic Republic of Congo, accounted for over Australia-based Gippsland Ltd is developing a huge 60 per cent of global tantalum production in 2009. In tantalum-tin resource in Egypt. The project includes the 2002 Australia produced about 60 per cent of global 44.5 million tonne Abu Dabbab deposit, scheduled for tantalum but this figure dropped to less than ten per cent production by 2013, and the 98 million tonne Nuweibi in 2009 due to the temporary closure of the Wodgina and project. The company plans to produce about 300 tonnes Greenbushes mines. Additional production comes mostly of tantalum pentoxide a year from its Abu Dabbab opera- from Brazil (about 20 per cent in 2009) with minor amounts tion (Gippsland, 2011). also produced in Malaysia and Canada (Figure 14). Globe Metals and Mining also plans to bring its Kanyika Projects under development project in Malawi into full production by 2013. The operation The growing markets for niobium and tantalum have led will produce approximately 200 tonnes of ferro-niobium, and to an increase in exploration for niobium and tantalum 190 tonnes of tantalum pentoxide per year. The operation in recent years. Many of the deposits being investigated will also produce by-product uranium oxide and zirconium contain both metals but, in many cases one is predomi- silicate (Schwela, 2010b). nant. Current exploration for both metals is focussed on carbonatite, peralkaline granite-hosted and LCT-type Australian company, Ram Resources Ltd, has acquired granite-hosted deposits (Table 8). 51 per cent of the Motzfeldt polymetallic deposit in south- ern Greenland. Motzfeldt has the potential to be a giant Global Advanced Metals (GAM), formerly Talison Metals, niobium-tantalum deposit with possible by-product rare has re-started mining at its Wodgina operation in Aus- earth elements. The overall resource could be in the region tralia. Tantalum pentoxide will be produced at Wodgina at of 500 million tonnes although further work is required to a rate of 318 tonnes per year, although at full capacity it define a JORC compliant estimate (RamResources, 2011). could be double that quantity. Material from Wodgina will be processed at Global Advanced Metals’ Greenbushes operation. Mining is not currently taking place at Green- World trade bushes (Schwela, 2010b). It is difficult to obtain trade data specific to niobium and tantalum as they are commonly reported under a combined

Deposit Location Company Type Resources* % Nb2O5 % Ta2O5 (Mt) Anita Canada Les Mineraux Carbonatite- 23.75 0.186 0.019 Crevier nepheline syenite Motzfeldt Greenland Ram Resources Alkaline-peral- 500 0.13–0.15 0.011–0.013 kaline granite Crevier Canada MDN Inc. Carbonatite- 25.4 0.2 0.023 nepheline syenite Kanyika Malawi Globe Metals Alkaline-peral- 21 0.41 0.018 and Mining kaline granite Abu Dabbab Egypt Gippsland LCT granite 44.5 n.a. 0.025

Nuweibi Egypt Gippsland LCT granite 98 0.0095 0.014

Marropino Mozambique Noventa LCT granite 7.4 n.a. 0.023

Upper Fir British Commerce Re- Carbonatite- 36.4 0.17 0.019 Columbia sources Corp. nepheline syenite *Includes all categories of resource

Table 8 Selected niobium-tantalum projects under development. (Schwela, 2010b, Gippsland, 2011, RamResources, 2011). Niobium–tantalum

21 www.MineralsUK.com 22 Niobium–tantalum in 2009(Papp, 2011a). Figure 15 Percentage Imports overtaken Australiaasexportersoftantalum,althoughthis South America(Brazil)andCentralAfricahaverecently ing countriesisnotavailable. States (Figure 15). Comparable data for other major import- suppliers ofniobiumoresandconcentratestotheUnited (48 percent)andCanada(32werethemain metal and86percentofitsniobiumoxide.Mozambique 69 percentofitsferro-niobium,91niobium In 2009,BrazilsuppliedtheUnitedStateswithabout United States,JapanandChina. cant importersofthesematerialsincludeGermany, the Canada isthesecondlargestexporterofniobium.Signifi- form offerro-niobium,niobiumoxideandmetal. Brazil istheworld’s largestexporterofniobium,inthe other countries. and consequentlyitisentirelydependentonimportsfrom The EUdoesnotcurrentlyproduceanyniobiumortantalum efficiency andincreasedrecycling. of sustainabledevelopmentpractices,improvedresource gate againstthesesupplyrisks.Theseincludethepromotion on theEUeconomy. Strategiesarebeingconsidered tomiti- potential riskofsupplyshortagewithanassociatedimpact (EC., 2010).ThismeansthattheECconsiderstheretobea identified niobiumandtantalumas‘critical’rawmaterials tutes arenotavailable,theEuropeanCommission(EC)has ores, andbecauseformanyapplicationseffectivesubsti- Due toconcernsoverfutureaccessniobiumandtantalum ucts, oresandconcentrates,chemicals. traded inavarietyofformsincludingmetallurgicalprod- is compoundedbythefactthatniobiumandtantalumare trade codewithvanadiumandrhenium.Thisuncertainty 100 10 20 30 40 50 60 70 80 90 0

Sources ofUnited Statesniobiumimports Brazil Mozambique Ore andConcentrate Niobium oxide Niobium Metal Ferro-niobium Canada powder inexcess ofUS$300perpound(Reisman, 2011). about US$240per pound;andcapacitor-grade tantalum was aboutUS$120perpound; tantalumoxidesandsalts ferent price:inFebruary2011 tantalum oreandconcentrate Tantalum istradedinthreeforms,eachcommandingadif- Burns, 2009). possibly duetoincreaseddemand(RamResources,2011, were reportedtobeaboutUS$3941perkilogram, to 14perkilogram.However, asofFebruary2011,prices Prior to2007ferro-niobiumpriceslayintherangeUS$12 prices basedoninterviewswithbuyersandsellers. confidential. Trade journalssometimes reportindicative negotiated betweenbuyerandsellergenerallyremain openly tradedonanymetalexchange;contractpricesare Unlike manyothermetalsniobiumandtantalumarenot Prices Portugal (14percent)(Figure16). came fromChina(15percent),Germany(12cent)and cent); tantalumscrapimportsintotheUnitedStates cent), (27percent)andGermany(15 tantalum metaltotheUnitedStateswereChina(27per supplied afurther21percent.Themainexportersof 66 percentofitstantalumconcentratewhilstCanada In 2009,AustraliasuppliedtheUnitedStateswithabout slags totheEUincludeJapan,ChinaandKazakhstan. Currently themainexportersoftantalumores,scrap,andtin are intheformoftantalumoxideoraspotassiumsalt. Germany, JapanandChina.Themajorityoftantalumexports tantalum manufacturingandprocessingwasteincluding Greenbushes mines.Anumberofcountriescurrentlytrade is likelytochangewiththere-openingofWodgina and in 2009 Figure 16 Percentage Imports 10 20 30 40 50 60 70 0 utai aaaCiaKzksa emn Portugal Germany Kazakhstan China Canada Australia (Papp, 2011b).

Sources ofUnitedStatestantalumimports www.MineralsUK.com Scrap Metal Concentrate and substitution Focus on Britain Recycling Niobium and tantalum have never been commercially Both niobium and tantalum can be recovered from waste exploited anywhere in Britain, and there has been no metals and scrap and in both cases account for up to systematic evaluation of niobium and tantalum resources. 20 per cent of total supply (EC., 2010). Niobium is primar- Locations of potential interest are confined to alkaline and ily recovered from niobium-steels and superalloys, but the associated igneous rocks which are relatively rare in the amount recovered from other sources is minor. Tantalum UK. is recovered from a number of different items including cemented carbides and alloys; however, recycling from ca- Carbonatites and associated rocks pacitors is difficult and current technology is poorly devel- The only confirmed carbonatite body in the UK is associ- oped. Other items from which tantalum can be recovered ated with the Silurian89 alkaline Loch Borralan Complex include spent sputtering targets88, and edge trimmings and in the north-west Highlands of Scotland. The whole of shavings from metallurgical processes. the Loch Borralan Complex (including the carbonatite and associated ultramafic rocks) has generally low bulk-rock Substitution niobium contents, and niobium-bearing minerals such as Many of the uses of niobium and tantalum are very specific pyrochlore are not present (Young et al., 1994). and substitutes often incur a cost or performance penalty. Due to the physical and chemical similarities of niobium Carbonate veins and evidence of sodium metasomatism and tantalum the two metals can be substituted for each (fenitisation) have been found at several localities along other in a number of applications, for example, in corro- the Great Glen Fault near Inverness, and have been at- sion- resistant coatings. Where strength at high tempera- tributed to carbonatitic magmatism. Bulk-rock analyses ture is required in steel, metals such as molybdenum and indicate that niobium contents in the carbonate and fenite vanadium are often used as substitutes for niobium and veins are higher than in the surrounding country rocks, tantalum. Efforts are currently being made to substitute but niobium-bearing minerals such as pyrochlore have tantalum by aluminium or ceramics (Table 9 and 10). Some not been found (Garson et al., 1984). These veins are of applications are unique and as such suitable substitutes relatively limited extent, but it is possible that a larger are currently not available, for example, porous tantalum carbonatite mass may exist at depth. alloys used in the manufacture of prosthetic body parts. Alkaline to peralkaline granites and syenites Niobium product/ Possible substitutes Alkaline igneous rocks in the British Isles were formed dur- application ing three main magmatic episodes: the Caledonian mag- HSLA steels Molybdenum and vanadium matism (Silurian to Devonian); the Permo-Carboniferous90; 91 Stainless and high- Tantalum and titanium and the Palaeogene . strength steels Caledonian igneous rocks are widespread, but the vast High-temperature Ceramics, molybdenum, tantalum applications and tungsten majority are calc-alkaline in composition. A suite of alkaline, largely syenitic, plutons occurs in the north-west Table 9 Potential niobium substitutes. (Papp, 2011a). Highlands of Scotland, but all these intrusions are char- acterised by low bulk-rock niobium contents (Fowler et Tantalum product/ Possible substitutes al., 2008). Niobium- and tantalum-bearing minerals have application not been recognised in these syenites. In Wales, Ordovi- Capacitor manufacture Aluminium and ceramics cian to Silurian alkaline microgranites with relatively high Carbide material Niobium bulk-rock niobium contents (up to 150 ppm) occur both in production Snowdonia and the Llyˆn Peninsula. The Mynydd Mawr Corrosion-resistant Glass, niobium, , microgranite in Snowdonia has been reported to contain equipment titanium and zirconium niobium and tantalum minerals (Bevins and Mason, 2010, High-temperature , iridium, molybdenum, Young et al., 2002). applications niobium, and tungsten

Table 10 Potential tantalum substitutes. (Papp, 2011b). 89 Silurian: a unit of geological time between 443 and 416 million years ago. 90 Permo-carboniferous: a unit of geological time around 300 million years ago 88 Sputtering target: metallic materials used as targets for the deposition of that represents the end of the Carboniferous and the start of the Permian. 91

Niobium–tantalum thin-films of tantalum compounds (e.g. tantalum carbide). Palaeogene: a unit of geological time between 65 and 23 million years ago. 23 24 Niobium–tantalum tholeiitic and intoNorthernIreland.Themajorityoftheserocksare western sideofBritain,fromtheBristolChanneltoStKilda The BritishPalaeogeneigneousprovinceextendsalongthe ed througheithermagmaticorhydrothermalprocesses. are norecordsofniobium-bearingmineralsbeingconcentrat- niobium contents,upto180ppm(Uptonetal.,2007),butthere These trachyticigneousmasseshaverelativelyhighbulk-rock central Scotland,whicharetypicallytrachytic not beeninvestigatedindetail(IGS,1975). sediment samples,butthesourceofthesemineralshas ilmenorutile andcassiteritehavebeenfoundinstream- the CairngormGraniteinScotland,,columbite, has alsobeendescribedfromtheseveins(Young, 1987).In mineral veinsoccurwithintheSkiddawGranite;columbite age. AtCarrockFellintheLakeDistrict,tungsten–bearing LCT-type mineralisationisrareingranitoidsofCaledonian minerals havenotbeenrecordedelsewhereinthisarea. plex ofnorth-westernScotland,butniobiumandtantalum occur acrossmuchoftheArchaeanLewisianGneissCom- (von-Knorring andDearnley, 1960).Pegmatitesofthisage for alkalifeldspar, alsocontainscolumbite andpyrochlore Chaipaval pegmatite,whichhaspreviouslybeenquarried ing muscovite,biotite,berylandraretourmaline.The These havetypicalLCTmineralassemblages,includ- occur ontheislandofSouthHarris,inOuterHebrides. A numberoflargePalaeoproterozoicgraniticpegmatites Granites andpegmatitesoftheLCTfamily been reportedfromtheLundyGranite(Thorpeetal.,1995). in miarolitic reported fromthenorthernArrangranite,whereitoccurs sonite, aniobium-andtantalum-bearingoxide,hasbeen moderate bulk-rockniobiumcontents(<50ppm).Fergu- element dataforthesegranitesgenerallyindicatelowto evolved rocksarepresent,chieflyasgraniticplutons. Trace surface. ago. granitic pegmatites. formed intheoceans oratcontinentalmargins. a mineralcalledalkalifeldspar;thefine-grained equivalentofsyenite. which iscircularinplan,withaflatfloor andashallowdomedroof. Scotland andnorthernEnglandduringtheCarboniferous Alkaline magmatismwasextensiveincentraltosouthern 97 96 95 94 93 92 form asetofsmallplugs are maficvolcanicrocks.Morehighlyevolvedmagmaticrocks Permian periods,butthemajorityofexposedigneousrocks

Plug: asmall,cylindrical,bodyofigneousrock,emplacedbeneaththeEarth’s Carboniferous: aunitofgeologicaltimebetween359and299millionyears Miarolitic: atermfor crystal-linedcavitiescommonlyfoundin granitesand Tholeiitic: acertainsuiteofigneousrocks withdistinctchemistrytypically Trachytic: afine-grainedtypeofigneous rockcontainingabundantamountsof Laccolith: abodyofigneousrock,emplaced beneaththeEarth’s surface, 96 to basaltic in composition, but some more toalkalibasalticincomposition,butsomemore 97 1999). Columbite has cavities(Hyslopetal.,1999).Columbitehas 93 andlaccoliths 94 concentrated in concentratedin 95 in composition. incomposition. 92 and and REE Carbonatites oftheWorld, Explored DepositsofNband B Republic ofMalawi. Potential ofMalawi.MinistryEnergyandMines, belzile f B com [AccessedJanuary2011]. A Tantalum andNiobium.BerlinHeidelberg:Springer-Verlag. Guardian, p.25. Christmas laptop?Asktheeastern Congolese.The B Peterborough: JointNatureConservationCommittee. S R E,Y B Open FileReport. B Niobec Mine,Quebec,Canada The CanadianMineralogist,47,1329–1357. Granite, PitingaMiningDistrict,AmazonasState,Brazil. with theAlbite-EnrichedfaciesofMadeiraA-type F, (Y, Ree,Li)DepositandtheMassiveCryoliteassociated Anglo Americanplc.A across. In: Application ofTantalum, NiobiumandTheirCompounds. A References to formtheCornubianBatholith mineralisation. Thesurfaceoutcropsareconnectedatdepth classic LCTgranites,well-knownfortheirtinandtungsten The Variscan (Permian)granitesofsouth-westEnglandare 98 Rostowrack claypits(Symes,2010,Scottetal.,1998). with theStAustellGranite,atGunheath,Goonveanand also beenfoundinpegmatitesandtopazgranitesassociated dyke tonearbygranitesisuncertain.Columbite-tantalitehas (von-Knorring andCondliffe,1984).Therelationshipofthis iferous countryrocksonthenorth-westernsideofDartmoor the MeldonAplitemicrogranitedyke,whichintrudesCarbon- Columbite-tantalite andmicrolitehavebeenrecordedfrom their countryrocks,andinlatestagepegmatitesaplites. mally alteredveinswithintheupperpartsofgranitesand main tinandtungstenmineralisationoccursashydrother granites andtopazgranites,associatedpegmatites.The kilometres inlengthandincludesbiotitegranites,tourmaline

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40, A This commodity profile was produced by the British Geological Survey (2011).

It was compiled by Richard Shaw and Kathryn Goodenough with the assistance of Gus Gunn, Teresa Brown and Debbie Rayner.

This report is one of a series of Commodity Profiles available to download free-of-charge from www.MineralsUK.com.

For further information please contact:

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