Mineralogical and chemical characterization of DD3 kaolin from the east of Algeria

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Pleasecitethisarticleinpressas:H.Senoussi,etal.,MineralogicalandchemicalcharacterizationofDD3kaolinfromtheeastofAlgeria,Bol.

w w w . e l s e v i e r . e s / b s e c v

Mineralogical

and

chemical

characterization

of

DD3

kaolin

from

the

east

of

Algeria

Hamza

Senoussi

a

_,

_Hocine

_Osmani

a

_,

_Christian

_Courtois

b

_,

_Mohamed

_el

_Hadi

_Bourahli

a,∗

Q1

a_Non_Metallic_Materials_Laboratory,_Institute_of_Optics_and_Precision_Mechanics,_University_Ferhat_Abbes,_Setif₁_Algeria b_Ceramics_Materials_and_Processes_Laboratory,_University_of_Valenciennes_and_{Hainaut-Cambresis,}_France

a

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i

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e

i

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Articlehistory: Received1July2015 Accepted1December2015 Availableonlinexxx Keywords: Kaolin Halloysite Identiﬁcation Intercalation

Organicmoleculesintercalation

a

b

s

t

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c

t

Themineralogicalandchemicalcharacteristics,basedonX-raydiffraction(XRD)and scan-ningelectronmicroscopy,ofakaolinknownasDD3,fromeasternAlgeriawereexamined inthepresentstudy.

TheresultsshowedthatkaolinDD3hasanaluminacontentof39%.TheSiO2/Al2O3molar

ratioof2.14isclosetothatofapurehalloysite.Thehematiteconcentrationisrelatively largeandtheﬂuxoxidesratiosremainasacceptableimpurities.Microscopicobservations showedapredominanttubularhalloysitephase,ﬂattenedhexagonalplatelets correspond-ingtothepresenceofkaoliniteanditspolymorphs(nacrite,dickite),andhydratedalumina. TheSiO2/Al2O3molarratioandtubularDD3suggestpossibleusesintechnicalceramicsand

nanotechnologyapplications.

AnalysisbyXRDrevealedthepresenceofmanyphases.Thermaltreatmentat450◦Cand chemicaltreatmentwithHClconﬁrmedthepresenceofhalloysite.Theinclusionintheclay oforganicmolecules(dimethylsulfoxide(DMSO),DMF,anddilutedglycerol)showedthatthe DMSOledtoexpansionoftheinter-planardistance.TheintercalationbyDMSOmolecules resultedinashiftofthebasalpeakfrom10to11.02 ˚Aandpartialdisplacementofthepeak from3.35to3.65 ˚A.Thesetwopeaksarecharacteristicofhalloysite.Thepresenceofresidual nacritewasalsoconﬁrmedbytheshiftofthepeakobservedat3.35 ˚A.

AfullanalysisoftheXRDpatternsusingtheMatchsoftware,basedontheseresults, showedthattheDD3clayconsistsof>60%halloysite.

(http://creativecommons.org/licenses/by-nc-nd/4.0/).

Caracterización

mineralógica

y

química

de

caolinita

DD3

procedente

del

este

de

Argelia

Palabrasclave: Caolinita Halloysita Identiﬁcación

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Enelpresenteestudioseexaminaronlascaracterísticasmineralógicasyquímicas, basán-donosenanálisismediantedifracciónderayosX(DRX)ymicroscopioelectrónicodebarrido, deunacaolinitadenominadaDD3,procedentedelestedeArgelia.

∗ _{Corresponding}_author.

E-mailaddresses:h.senoussi@mail.lagh-univ.dz(H.Senoussi),hocineosmani@yahoo.fr(H.Osmani),

Christian.Courtois@univ-valenciennes.fr(C.Courtois),bourahlim@yahoo.fr(M.e.H.Bourahli).

http://dx.doi.org/10.1016/j.bsecv.2015.12.001

(http://creativecommons.org/licenses/by-nc-nd/4.0/). 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

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Intercalación

Intercalacióndemoléculas orgánicas

Losresultadosreﬂejaronquelacaolinitaposeeuncontenidodealúminadel39%.La pro-porciónmolarSiO2/Al2O3de2,14escercanaaladelahalloysitapura.Laconcentraciónde

hematitesesrelativamentegrande,ylaproporcióndeóxidosfundentessemuestracomo impurezasaceptables.Lasobservacionesalmicroscopioreﬂejaronunafasepredominante dehalloysitatubular,plaquetashexagonalesaplanadasquesecorrespondenconla presen-ciadecaolinitaysuspolimorfos(nacrita,dickita),yalúminahidratada.Laproporciónmolar SiO2/Al2O3ylaDD3tubularsugierenposiblesusosparacerámicatécnicayaplicacionesde

nanotecnología.

ElanálisismedianteDRXrevelólapresenciadediversasfases.Eltratamientotérmicoa 450◦CyeltratamientoquímicoconHClconﬁrmaronlapresenciadehalloysita.Lainclusión enlaarcillademoléculasorgánicas(dimetilsulfona(DMSO),DMF,ygliceroldiluido)mostró quelaDMSOconducíaalaexpansióndeladistanciainterplanar.Laintercalaciónporparte delasmoléculasdeDMSOoriginóuncambiodelvalormáximobasalde10a11,02 ˚A y undesplazamientodedichovalormáximode3,35a3,65 ˚A.Dichosdosvaloresmáximos soncaracterísticosdelahalloysita.Tambiénseconﬁrmólapresenciadenacritaresidual medianteelcambiodelvalormáximoobservadoa3,35 ˚A.

UnanálisiscompletodelospatronesdelaDRX,utilizandoelsoftwareMatch,basadoen dichosresultados,reﬂejóquelaarcillaDD3secomponede>60%dehalloysita.

(http://creativecommons.org/licenses/by-nc-nd/4.0/).

Introduction

Themostimportantmineralsinkaolinarekaoliniteand

hal-Q2

loysite.KaoliniteAl2Si2O5(OH)4isoftenusedasabaseforthe

synthesisofneworgano-mineralnanomaterialsdesignedfor applicationsinindustriesand forenvironmentalprotection

[12].Halloysitehadasimilarcompositionwithsomeexcess watermoleculespresentbetweenthelayersandoftenexhibits atubularmorphology.Halloysiteloseswatereasilyfromthe intermediatelayerandisfrequentinsomepartialdehydration state.FullyhydratedhalloysiteAl2Si2O5(OH)4·2H2Obecomes

increasinglyimportantbecauseofitsuseinnanotechnology applicationswhichtakesadvantageofitstubularhabit[18].

Typically,clayshaveahexagonalstructureoriented per-pendicularlytothe Caxis. Theinterlayersdistancevaries accordingtothetypeofclay.

FirstorderX-rayBragg reflectiondidnottotally identify themineralspresentintheclay.Thecompoundscomplexity causedamultiplereflectionofhigherorders(n=2,3,4,...) pro-motingthesuperpositionofthefirstorderpeakswiththoseof higherorders.Thepresenceofchloriteinthekaoliniteclayled tothesuperpositionofthepeakcorrespondingtothe reflec-tionofthefirstorderofthekaolinite(d=7 ˚A)withthatofthe secondorderreflectionofchlorite.Toremoveambiguityinthe identificationoftheseminerals,auxiliarytechniquestailored to the specificthermal properties and chemical properties ofthese clay minerals were used. Thecommon technique used consists of the intercalation of the clay mineral by organic molecules. Thelatter resulted inthe expansion of theinterlayerdistanceofbasallayers.Thisinducedashiftof thefirstorderpeakreflectiontosmallerangles.Theorganic moleculesusuallyused are:ethylene glycol orglycerin, N-methylformamid,hydrazin,potassiumacetateanddimethyl sulfoxide(DMSO).

The intercalation of these molecules between layers of nacritenotonlycausedanincreaseintheinterlayerdistance,

butalsosomeinter-sheetstranslation[1].Amongtheorganic moleculesused,theDMSOreducedthetranslationofthe octa-hedral site.In this case, the guestmoleculesoccupied the spacebetweenthetwositescausingadecreaseofthe coher-entdomainsizeconsistencybothinthedirectionofthelayers andintheperpendiculardirection(d002=11.19 ˚A).This

inter-calationcausedcleavageoftheparticles.Asimilarresultwas obtainedbyBookinetal.[2]fordickite.Anotherstudyis con-cernedwiththeintercalationofhalloysiteenrichedkaolinite claybyformamides,potassiumacetateandhydrazine[4].The Q3

treatmentoftheﬁrsttwomolecules,followedbywashingwith waterorwaterandglycerol,ledtothetotalexpansionof hal-loysite.Thepeakat7.2 ˚Amovedto10.1 ˚Aand remainedin this position.Withkaolin,thesetreatmentsdidnotleadto suchdisplacement.Nevertheless,intercalationbyformamide and potassiumacetatemolecules underestimatedthe pro-portionofhalloysitecomparedtotheuseofhydrazine.This wasbecauseofthepresenceofthedisordered kaolinite,as halloysitemaintaineditshydratedstateaftertheremovalof hydrazinebywaterwashing. Q4

Therefore, thesetreatmentsdidnotallowaquantitative estimationoftheproportionofhalloysiteinkaolin–halloysite mixtures.Thequantiﬁcationofkaolinispossiblebyusinga prolonged intercalationmethod(over18 days).Inthis con-text,itappearedthatthehydrazinewasthemostappropriate intercalationmolecule.Itledtoanalmosttotaldisplacement. Itwasalsonotedthatthecrystallineandthegrainsizehad someinﬂuenceontheintercalationquality[4].

Formamide moleculeswereusedtodifferentiate kaolin-iteandhalloysite[7].Immersionofhalloysiteinaformamide solutionforashorttime(<1h)enabledacompleteexpansion oftheclay.Kaolinitewasrathersusceptibletosuchtreatment onlyafteralongperiod(4h).Atatemperaturegreaterthan 110◦C,this treatmentwas nomore effectiveon halloysite. Thehighertemperature treatmentcausedthe transitionof halloysite(10 ˚A)todeﬁnitivemetahalloysite(7.2 ˚A).

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JacksonandAbdelkader[13]obtainedthetotalexpansion ofﬁnetypeIVkaoliniticﬁreclays.Theyusedground kaolin-itewithCsClandtheresultingmixturewasinterposedwith hydrazineandheatedat65◦Cfor24h.Asecondinterposed procedurewasmadewithDMSOand themixtureobtained washeatedat90◦Cfor24h.Thismultipletreatmentledtoa shiftoftheXRDpeakfrom7.2to11.2 ˚A.

Theintercalationofwellcrystallizedhalloysitewith ethy-leneglycolconﬁrmedtheresultsofHillierandMacEwan[5,17]. Thisledtoadecreaseintheintensityof7.2 ˚Apeakand anincreaseintheintensityof3.58 ˚Apeak,whichresultedin aratioreductionI(7.2 ˚A)/I(3.58 ˚A).Theintercalationof ethy-leneglycolpromotedashiftin(7.2 ˚A)peakto2.58 ˚Aleading toathirdorderreﬂectionpeakclosetothepeakofhalloysite (3.58 ˚A).

Otherauthorshavestudiedthede-intercalationof kaolin-iteanditseffectonthecrystallineofthehostmaterial[11]. ItwasreportedthattheintercalationofN-methylformamid, especiallyDMSO,causedalargestructuraldisorder.Octavian andRouxhet [3], however,concludedthat the treatmentof kaolinitewithDMSOdidnotaltertheoriginalconﬁguration. Theheattreatmentbetween100and250◦C,waterwashing andthemethanolpreventedthedeformationofthecrystal lattice.Theproposedmethodforde-intercalationbyheating from100◦Cto250◦C,washingwithwaterandmethanolorCS2

[8]wasprobablythereasonfortheapparentcontradiction. Theprecedingworksmentionedrevealedthatathorough analysisofmulti-componentnaturalclayrequiredassociating severalothertechniquesinadditiontoSEM, EDXandXRD. Attemptingadifferenttypeofintercalationmoleculesmay removesomeambiguities.Inthis work,acompleteprocess analysisofDD3kaolin,basedonmorphologicalobservation, chemicalanalysisandXRDdiffractionassociatedwithtailored intercalationtreatments,waspresented.

Experimental

Rawmaterial

ThematerialstudiedisakaoliniticgrayclaydesignatedDD3 extractedfromamountainofeasternAlgeria(DjebelDebagh).

Physico-chemicaltreatment

TheidentiﬁcationofthedifferentphasespresentintheDD3 kaolinfromXRDmeasurementsrequiredtheuseofdifferent treatments.

Theﬁrstwasathermaldehydrationat450◦C.Thesecond wasmadeupofadehydrationstepatroomtemperature fol-lowedbydissolutioninhydrochloricacid(4N)forhalfanhour at20◦C.Thethirdtreatmentwasmadeupoftheintercalation oforganicmoleculesintheclaybysprayingawatersolution ofspeciﬁcadditives.Theusedorganicmoleculesinawater solution(10%water)areGlycerin,dimethylformamide(DMF)

[7]andDimethylsulfoxide(DMSO).TheDMSOwasalso inter-calatedinvaporform[8,14].Onegramofkaolinwith20mlof DMSOwasplacedinapyrexTM_sealed_enclosure._The_mixture

wasstirreduntilahomogeneoussolutionwasreachedand heatedat60◦Cfor12h. A1 Si 0 p Ca Cr Mn 8100 Kev 0.000 10µm

Fig.1–TypicalX-EDSresultsandlocalizationofthe analyzedareasonsinteredDD3kaolin.

AnalysisofsolidphasesbyXRD

ThesampleswereanalyzedusingaPhillipsPW3050/60 diffrac-tometerwithacopperanticathode(=1.540598 ˚A).Theground powder(particlesize<50␮m)wascompactedandﬂattened betweentwoglassslidestoincreasethepreferentialgrain ori-entation.Thesampleswerethenscannedfrom4to90◦witha stepof0.02◦persecond.Matchsoftwarewasusedtoidentify themainphasesusingtheCODInorganic20130415database.

MicroscopyanalysisbySEM-EDS

Theobservationsofthemorphologyofthevariousmineralsin thekaolinDD3weremadeusingaHitachiS4700SEM.Before observation,thepowderofkaolinwasdispersedinacetone underultrasonicvibrationsanddried.Chromium metalliza-tionwasperformedbyvacuumdeposition.

Furthermore, an Energy-Dispersive X-ray Spectrometry (EDS)wasusedintandemwiththeSEMforidentiﬁcationof kaolinDD3chemicalelements.

Results

and

discussion

SEM-EDSanalyses

The main elements and their corresponding oxides were determined byX-EDS.Thelocalizationofsixanalyzedsites designatedbynumbersandatypicalX-EDScurveisshownin

Fig.1.

SEMobservations

SEMphotographsofDD3kaolinpowder(Fig.2)showed irreg-ular grainsizesand variousparticleshapes.Thisimperfect structure was linked to some disturbances in the octahe-drallayerinwhichironmayreplacealuminum[10].Grains

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Pleasecitethisarticleinpressas:H.Senoussi,etal.,MineralogicalandchemicalcharacterizationofDD3kaolinfromtheeastofAlgeria,Bol. Tubule

Quasi hexagonal Flat plate Tubule-sheet coiled

1µm 1µm

Fig.2–SEMobservationofDD3kaolin.

exhibited irregular tubular shapes, sometimes elongated (rolledsheets)andinsomecasesspherical.Theseshapesare indicativeofhalloysite.Thetubularformwaspredominant.It allowedthestorageofwater,conferringplasticity.The tubu-larrodswere entangled(Fig.2a),givinggood tear strength tothematerial.Additionally,thepresenceofnearhexagonal shapesandﬂattenedplateletsprobablyindicatedthepresence ofnacrite,dickiteandhydratedalumina,characterizingthe presenceofkaolinite,whosebasalsurfaceswere perpendicu-lartothe(001)directionandsidefacesperpendicularto(010) and(110)directions.Thepredominanttubularshapedgrains revealedthathalloysitewasthemainmineralconstituentof thestudiedclay.

Themain chemical elements detectedand their oxides

(Table1)conﬁrmedtheoriginofclay.Thepredominant

con-stituentsweresilicaandalumina.TheSiO2/Al2O3molarratio

was2.14.Thisratiowasveryclosetothatofapurehalloysite. Thedispersion ofthe observedvaluesforthesetwooxides showedthatthechosensitesexhibitedvariablecompositions. Theproportionsofotheroxides(Fe2O3,MgO,Na2O,K2Oand

MnO)remainedacceptablesuchasimpuritiesrelativeto con-ventionalapplication.Thepresenceoftheseoxidesinsuch concentrationmaybeasignoftheexistenceofchloriteinthe clay.Theirpresenceplayedanimportantroleintheformation

Table1–Weightpercentageofdifferentchemical elementsandcalculatedoxidesinDD3kaolin.

Element wt(%) SD Calculatedoxides wt(%) SD

O 47.65 0.69 – – – Si 23.08 1.97 SiO2 49.00 4.22 Al 20.84 3.56 Al2O3 39.00 6.74 Fe 3.12 0.61 Fe2O3 4.50 0.87 Na 1.78 0.91 MgO 2.90 0.61 Mg 1.74 0.36 Na2O 2.41 1.22 Ca 1.15 1.03 CaO 1.63 0.84 Mn 0.49 0.15 MnO 0.62 – K 0.23 0.11 K2O 0.34 0.14

SD,standarddeviation;wt,weightaverageamount.

4.42Å 4.09Å 3.5Å 2.026Å Treated with Hcl (4N) 4.83Å 7.2Å 10Å _4.36Å 4 8 12 16 20 24 28 32 2Theta (º) 36 40 44 48 Treated at T=450ºC Untreated 7.3Å

Fig.3–Effectofheattreatmentat450◦CandHClonthe

XRDspectraofDD3kaolin.

andevolutionofcrystallinephasesduringtheheattreatment ofkaolin.Itappearedthattheconcentrationofhematitewas relativelylarge.

XRDcharacterization

TheanalysisofXRDspectrawasdifﬁcultbecauseDD3kaolin containedseveralmineralphasesandmanyimpurities.The observedoverlappingpeaksmadecomplextheirfull identiﬁ-cation[9].Additionaltreatmentswereusedtoremovesome ambiguity.Thesewerealow-temperaturethermaltreatment (450◦C), achlorhydricacid chemicalattack(4N)and aclay interlayerintercalationwithorganicmolecules.

TheobtainedXRDspectraofDD3(<50microns)forthe thermallyorchemicallytreatedsamplesincomparisonwith anun-treatedcaseisshowninFig.3.Atlowdiffractionangles, there wasa fairlylarge continuousbackground becauseof Lorentz polarization [15] and the presence of amorphous phases.Twobroadpeaks(thefirstonebetween19◦and33◦and thesecondonebetween34◦and43◦)werealsoobserved. Fur-thermore,thelowintensityandthemoreorlesspronounced asymmetryofthepeaksatthesmallestangleswerelikelyas aresultofthegreaterdisorderofthestructureofthiskaolin. The peak at 10 ˚A could be attributed to both hydrated halloysite-type (10 ˚A) than illite, muscovite, or phlogopite phases. The thermal treatment caused the displacement of the 10 ˚A peak to 7.2 ˚A with improved peak symmetry. Halloysite was the onlydioctahedral 1:1 layersilicate that dehydratesatsuchlowtemperature[7].Thiscausedashift ofits XRDpeak confirmingthat the10 ˚A peakcorresponds tohydratedhalloysite(001)(DRXdata:halloysitePDFfile 29-1489,tometahalloysitePDFfile29-1487).Inanobviousway,the gibbsitedehydroxylationatsuchtemperaturegiveamorphous alumina[6], ledtothe disappearanceofthepeakat4.83 ˚A. Theremainingpeakskepttheiroriginalposition.Thesame effectwasobtainedbydehydrationwithhydrochloricacidHCl forhalf anhour.Inthiscase, thehalloysitepeak shifteda

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Pleasecitethisarticleinpressas:H.Senoussi,etal.,MineralogicalandchemicalcharacterizationofDD3kaolinfromtheeastofAlgeria,Bol. 11.02Å 10Å 4.36Å 3.65Å 3.35Å 4.83Å 7.2Å DMSO Vapor DMF Glycerin DMSO Crude 48 44 40 36 2Theta (º) 32 28 24 20 16 12 8 4

Fig.4–Effectofintercalationoforganicmoleculesinthe DD3kaolinonXRDspectra.

littletothenewposition7.30 ˚A.Theshrinkagebecauseofthe heattreatmentat450◦Cwasslightlyhigherthanthatobtained chemicallywithHCl.Inthislastcase,anincreaseinthepeak intensitywasobservedprobablybecauseofimpurities disso-lutionandtherearrangementofthedisorderedphases.The (001)peakofhallosyite(4.36 ˚A)alsoshiftedto4.09 ˚AafterHCl treatment.Anewpeakappearedat2.026 ˚Aandwasattributed toironoxide(Fe3O4)(JCPDSﬁle65-3107)resultinginvarious

mineralsacidicattackssuchaschlorite.

XRDdiagramsaftertheinsertionoforganicmoleculesare showninFig.4.ExpansionisreducedafterDMSOwasinserted insolution form. Thiscould be explainedby the presence ofamoreresistanttointercalationsuchaskaoliniteand/or itspolymorphs[16].Indeed,the7.17 ˚Apeakcorrespondingto kaoliniteunderwentaslightshiftto7.2 ˚A.Nosucheffectwas observedintheXRDdiagramafteratreatmentwithglycerol. TheintercalationofmoleculesofDMSOand DMFinvapor formresultedinacomplete displacementofthebasepeak from10 ˚Ato11.02 ˚A.Aminorshiftofanotherpeakfrom3.35 ˚A to3.65 ˚Awas alsoobserved.Theexpansionwas more pro-nouncedinthecaseofDMSOwhosemoleculeswere more orless bulky.Thetwo shiftedpeaks belongedto(001) and (003)halloysite.Thisisconsistentwiththeotherresultsthat showedthatintercalationofformamideswaseffectiveeven duringanexposureofless than onehour [7]. Peaks corre-spondingtokaolinite,however,didnotundergoanychange. ThepresenttreatmentwasprobablyinsufﬁcientasCostanzo etal.reported[14].Thekaoliniteunderwenttotalexpansion whenitwassubjectedtoanintercalationtreatmentwitha steamDMSOat60◦Conlyafteraperiodoftendays.The3.25 ˚A peakshiftto3.65 ˚Amaybeduetothepossiblepresenceof nacriteandcertainlyquantityofkaolinite,dickiteandnacrite together.

Matchsoftware was used to analyze the obtained DD3 clayXRDdiagrams.Polynomiallow-passsmoothinginterval

H-Halloysite K-Kaolinite G-Gibbsite M-Magnetite Di-Dickite Q-Quartz N-Nacrite

b

a

T-Todorokite C-Chlorite Hi-Hematite M Di Hi H N Q-Di H N G K T H C K-N Hi M 70 65 60 55 50 45 40 35 10 15 20 2Theta (º) 25 30

Fig.5–FullanalysisofDD3kaolinXRDdiagrams(a)◦2 from3◦to30◦,(b)◦2from30◦to70◦.

convolutionofelevenpointswasdone toreducetheeffect ofbackground noise.For theobtaineddiagram (Fig.5), the mainpeakswereindexedbythemostlikelyminerals(indexed byletter).Inthisﬁgure,peakscloseto10 ˚A,4.36 ˚Aand3.35 ˚A wereattributedtoquartzandthe4.83 ˚Apeakwasattributedto

Table2–Fullidentiﬁcationofmineralspresentinthe DD3kaolin.

Mineralphases(DD3) Weightamount(%)

Aluminosilicates Halloysite(H) 63–66 Kaolinite(K) 2–3 Nacrite(N) 7–9 Dickite(Di) 1–2 Chlorite(C) 6–8 Silica Quartz(Q) 5–7 Aluminacompound Gibbsite(G) 7–8 Other Hematite(Hi) 2–3 Magnetite(M) 1–2 Todorokite(T) 2–3 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291

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gibbsite.Severalweakreﬂectionpeaks,however,didnotseem tocorrespondtothesetwophases.

Relativeamountsofeachphaseweredeterminedand pre-sented (Table 2). They revealed that the main phase was halloysitewithanaverageamountof62wt%.

Conclusion

ThechemicalandmineralogicalanalysisofDD3kaolinwas achievedbyusingdifferentandcomplementaryintercalation characterizationtechniques.

EDXchemicalanalysisindicatedthepresenceofthehigh amountofalumina(Al2O3)witha(SiO2/Al2O3)molarratioof

2.14similartothatofapurehalloysite.Inaddition,the pres-enceofthehighamountofFe(III),Mg,Na,MnandCamay indicatethepresenceofchloriteandtodorokite.

SEM observation showed imperfect tubular grains attributed to halloysite as the predominant structure. The imperfection was because of the disturbances in the octahedral layer or iron replacing aluminum. In addition, the presence of quasi-ﬂattened hexagonal platelets was attributed to kaolinite and its polymorphs (dickite and nacrite)andtohydratedalumina.

AfullanalysisofXRDdiagramsrequiredtheuseof sev-eral additional intercalation treatments to identify several disputablepeaks.Theheattreatmentat450◦Ccausedashift ofaﬁrstpeakfrom10.06 ˚Ato7.32 ˚Athatisthecharacteristic ofthepresenceofhydratedhalloysite.Thesameeffectwas obtainedusingatreatmentwithhydrochloricacidHCl(4N) forhalfanhour.Inthiscase,thepeakbarelyshiftedtothe newposition7.30 ˚A.Moreover,thisacidictreatmentpromoted theappearanceofapeakat2.026 ˚Awhichwasaresultofiron oxideextractedfromchloritebythischemicaltreatment.

TheresultsobtainedbytheinsertionofDMSOandglycerol byimmersionduring1hin10%dilutedwatersolutionshowed anexpansionoftheinterplanardistanceofkaolinwithDMSO and nochange withglycerol. In addition, theintercalation withDMSOinvaporformandDMFresultedinthecomplete shiftofthe10 ˚Abasalpeakto11.02 ˚Aandpartialdisplacement ofpeak3.35 ˚Atopeak3.65 ˚A.Thesetwopeakscorrespondedto (001)and(003)halloysite.Theresidualpeakat3.35 ˚Aobserved aftervaportreatmentwasprobablybecauseofapolymorph ofkaolinite(nacrite).

Theseresults,basedonthecomplementarymethodsused, showedthattheDD3claywasmainlycomposedofhalloysite. Anear60%halloysiteratiowasdeterminedbasedonMach software.

Acknowledgments

TheauthorswouldliketothankProfA.LERICHE,Laboratoire desmatériauxcéramiques etprocédésassociésandProfA. Bataille,Laboratoiredestructuresetpropriétésdel’étatsolide UMRCNRS8008FrancefortheircontributiontoXRD,SEMand EDSanalysis.

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[1]A.BenHajAmara,H.BenRhaim,A.Plancon,Evolution structuraledelaNacriteenfonctiondelanaturedes moléculesorganiquesintercalées,J.Appl.Crystallogr.33 (2000)1351–1359.

[2]A.S.V.Bookin,A.Drits,A.Plancon,C.Tchoubar,Stacking faultsinkaolingroupmineralsinthelightofrealstructural features,ClaysClayMiner.37(1989)297–307.

[3]A.Octavian,P.Rouxhet,Noteontheintercalationof kaolinite,Dickiteandhalloysitebydimethyl-sulfoxide,Clays ClayMiner.25(1977)259–263.

[4]B.K.G.Theng,G.J.Churchman,J.S.Whitton,G.G.C.Claridge, Comparisonofintercalationmethodsfordifferentiating halloysitefromkaolinite,ClaysClayMiner.32(1984)249–258. [5]D.M.C.MacEwan,Halloysiteorganiccomplexes,Nature157

(1946)157–160.

[6]E.Damigos,Déshydratationdelaboehmiteenaluminede transitionétudethermodynamiqueetstructurale(These doctorat),EcoleNationaleSupérieure,Saint-Etienne,France, 1987.

[7]G.J.Churchman,J.S.Whitton,G.C.Claridge,Intercalation methodusingformamidefordifferentiatinghalloysitefrom kaolinite,ClaysClayMiner.32(1984)241–248.

[8]G.J.Churchman,Relevanceofdifferentintercalationtestsfor distinguishinghalloysitefromkaoliniteinsoils,ClaysClays Miner.38(1990)591–599.

[9]H.Bounib,H.Osmani,K.Loucif,G.Chevalier,G.Fantozzi, Caractérisationmécaniqueetmicrostructural,AnalChim. Sci.Matériaux37(2012)171–184.

[10]J.P.Legros,Lesgrandssolsdumonde,PressePolytechnique etUniversitaireRomande,Lausanne,France,2007. [11]L.Heller-Kallai,E.Huard,R.Prost,Disorderinducedby

de-intercalationofDMSOfromkaolinite,ClayMiner.26 (1991)245–253.

[12]M.Jakub,W.Ewa,G.Adam,B.Eel ˙zbieta,B.Krzysztof,Surface areaandporosityofnanotubesobtainedfromkaolin mineralsofdifferentstructuralorder,ClaysClayMiner.59 (2012)116–135.

[13]M.L.Jackson,F.H.Abdelkader,Kaoliniteintercalation procedureforallsizesandtypeswithX-raydiffraction spacingdistinctivefromotherphyllosilicates,ClaysClay Miner.36(1978)81–87.

[14]P.M.Costanzo,R.F.Giese,OrderedHalloysite:

diméthylsulfoxideintercalate,ClaysClayMiner.34(1986) 105–107.

[15]R.C.Reynolds,TheLorentz-polarizationfactorandpreferred orientationinorientedclayaggregates,ClaysClayMiner.14 (1986)359–367.

[16]R.L.Frost,S.J.VanDerGaast,M.Zbik,J.I.Kioprogge,G.N. Paroz,Birdwoodkaolinite:ahighlyorderedkaolinitethatis difﬁculttointercalate,anXRD,SEMandRaman

spectroscopicstudy,Appl.ClaySci.20(2002)177–187. [17]S.Hillier,P.C.Ryan,Identiﬁcationofhalloysite(7 ˚A)by

ethyleneglycolsalvation‘MacEvanseffect’,ClaysClayMiner. 7(2002)487–496.

[18]Y.Peng,T.Daoyong,A.Faïza,Y.Wenchang,F.Mingde,L. Dong,H.Hongping,Changesinstructure,morphology, porosity,andsurfaceactivityofmesoporoushalloysite nanotubesunderheating,ClaysClayMiner.60(2012) 561–573. 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400