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Sudan AcademyAcademv of Science (SAS)(sAs)

Atomic Energy Researches Coordination Council

Extraction and Purification of Yellow Cake

A Dissertation Submitted in Partial Fulfillment of the Requirement for Diploma Degree in Nuclear Science (Chemistry)

By Elshafeea Hassan YYousif ousif (B.Sc.)

Supervisor: Dr. Adam Khatir Sam

January 20062006

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b .. r-Q -I 11r •t ACKNO\VLEDGMENTACKNOWLEDGMENT t I would like to thank honorable sllpervisorsupervisor D.AdamD.Adarn Khatir SamSanr forfcrr his • continuouscontitiuoussupport and guidance, supportsupport. and valuable instructions from || which I have benefited muchnruch in executing this work.rvork. • And also I would like to thank everyoneevery one who aided me in this work.rvork. || •I : ~J IIIIi

Elshafeea Hassan Yousif -. (High DiplomaDiplornaStudent) ~-.T-_-, t • ABSTRACTABSTRACT I 'l'ltis • This dissertationdisscrtationhashas reviewedrcvicrvedcurrentcurre nt studiesstudiesonon productionproductiorrandand T purificationpurilicationofol'yellorv yellow cakecake fromlionr llranium uraniumoresores byby both bothacidaciuranium uranium • 'l'hc l isotopes.isottlpes.The secondsecottdchapterclrapter coverscovers mining nriningand and millingmilling methods,methods, • uraniumuraniurnleachingleacltirtg chemistry,chernistry, precipitation,precipitation, andand purification purificationofof uraniumuraniunr t concentratecotlccntratebyby solventsolventextractionextractiotr andand possiblepossible impuritiesimpurities thatthat commonlycontmonly ,t • interferedinterl'eredwithrvith yellowyellorv cake.cake. The"t'he lastlast chapterchapter presentedpresented ongoingongoing literatureliterature I review.review. •t •I •T •T •T •t •r r• •I

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t AcknowlcdgmcntAckttolvlcdgtrtctrt .. I • Abstract .,. . II t Abstract (Arabic) . III • Table of contents . IV l of IV • List of tablestablcs . VI •f, List of figuresfirgures ' " '" VI il CHAPTERCI{AI'T'BITONEONtr UraniumUraniurnand it's deposits...... deposits 2 I 1.1l.l Introduction...... Introduction... 2 ,2 rF 1.2 UraniumUraniunrminerals...... minerals I 2 1.3L3 Geology ofo[ UraniumUraniurn .. 4

II 1.3.1 UnconfonnityUnconformity related deposits . 4 I 1.3.2 Sandstone deposits .. 4 I I 1.3.3 Quartz pebble conglomerateconglonrerate deposits ... . 5 1.3.41.3.4Vein deposits . 5 I, ~ . -- 1.3.5 Brecciasllreccias complexcornplex deposits .. 5 : 1.3.61.3.6Intrusivelntrusive deposits .. 5 • 1.3.7I.3.7PhosphoricPhosphoric deposits . 6 ..I 1.3.8t.3.8CollapseCollapsc breccias pipe deposits . 6 T 1.3.91.3.9Volcanic deposits . 6 • 1.3.10I .3.I 0 SurficialSurhcialdcposits . 6 1 T 1.3.111.3.1I MetasomatiteMetasonratitedeposits . 7I I 1.3.12| .3.12Metamorphic deposits . 7I I ; JI IVIV

I J-l f 1.3.13I I ligrites deposits . If .3. 3 deposits 7 I 1.3.141.3.I 4 BlackIllackshale deposits ' . 7 * 1.15I .I 5 Other type of deposits . 7 I 1.4 Uranium isotopes . 7 t• CHAPTERCIIAP'TBITTOIVTO\V • Nuclear fuel cyclecvcle " . 12r2 I 2.1 Uranium mining . 12t2 • 2.2 Uranium millingnrillirig . 12 I 2.3 Uranium Leaching .. 12l2 • 2.3.12.3.t Acid leach chemistrychemistrv for uraniuranium urn . 13 t lea~h 15 • 2.3.2 Alkaline leach chemistrychemis[ry for uranium . 15 2.4 Purification . 16 •il 2.5 Solvent extraction . 16l6 I 2.6 Stripping .. 18l8 2.7 Precipitation . 18l8 'THTTBE CHAI1TERCHAI'TBIt THREE I • Literature Review . 22 I ConclusionConclusiort . 272'7 f. ReferencesReflerences •••••••••••••••••••••••• 11 . 282;8 I ..I I ..I FI

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tI •I lfI vV ! .| IIIt t 'I'AI]L[S • LISTt,ISI OFOiI TABLES T Table (1.1):(l.l): list of somesonrecommoncontnron uraniumuraniunr mineralsnrinerals . 3 • J Table (1.2): uraniumuraniunrisotopes .. 8 •; •t -­t lISI'L[ST'OFOF FlCURESFICURIS tillI FigureFigurc(1.1): Uranium decay seriessenes . 9 I FigureFigurc(1.2): UraniumUraniunrActinium decay series .. 10l0 Figure (2.1): Generalized process for uranium extraction ...... J199 • t I Figure (2.2): SchematicSchernaticflow sheet of purificationpurihcationby • Solvent extraction .. 20 IIIT IIII •; •I •; •T •t •T •t •t LIrl VI

Ili ... ~ .J ----~~~~--~- II 11I •I •I •I ••I I •I • CHAPTER ONE •t URANlUMURANTUM AND IT'S DEPOSITS II ••I ..; I Il -.I I •I •t •I -­t •I II :'" I .JJ !:.-t, II

It URANIUMUIIANIUI\lANDr\ND IT'SlT'S DEPOSITSDEI'OSIT-S

It 1.1l.l Introduction:Introtluctiou:

I FollowingIrollowing the developmentdeveloprnentof the nuclear industry during and I• immediately after World War Il,II, attention was focused on developing • technologies, which could be used to upgrade and purify uranium from l low-grade sources. Initially the nuclear industry had relied on high-grade • uraniumuraniunrores fromltorn the BelgiumBelgiurnCongo and Canada. One of the main I participants in this developmentdevelopnrcntwas\\,as Union of South Africa. The I• production of yellowyellorvcake was an essential step in this developmentcleveloprnentr. 1• • 1.2 UraniumUrlniurn minerals:rninerals:

II An understandingurrdcrstandingof mineralizationrnineralizationconcepts ofo{'uranium uranium lead to better understandingundcrstandingof expected leaching behavior. In nature exist mainly in I! 4 the valencevalcnccstate UUa* ' (tetravalent)ltetravalent) and U

II UraniumUraniurnminerals may be termedtennedprimaryprirnary or secondary, depending upon

; their degree of oxidation and origin. The commoncomrnonUranium minerals are I listed in TableT'able(1.1).( l.l ).

H ~I The mostnrost importantinrportantpnmaryprimary ore minerals are uraninite, an oxide, T coffinite, a silicate. Pitchblende, also a primary mineral, is a caliform h variety of uraninite. fl l.r·.1 2 l:t,r It It t The secondary minerals may be formedfornredfromfi'onr elementselenrents and ions derived • fromtiom the primaryprirnarymineralsnrinerals fromfl'orn the intrinsic hosthosl constituents, or from I t migrating ground water, underurider varying pHpll conditions. The transformationtranslbrnration

fromlrom primary to secondary minerals is gradual and complex.conrplex. •II t• I • The most commonconrnronand widespread secondary minerals are carnotite, t tyuyamurite, metatyuyamurite, saleeite, sklodowskite, torbernite, • metatorbernite,metatorbemite,autunite, metaautunite,rnetaautunite, uranophate, schroeckingarite and I zeunerite. Minerals prefixed by Meta are chemically ahdaird physically the , • content~ I same but have lowerlorver water\\,ater content2. . • ( l Table (1.1 l.l ): list of some commoncomnron uraniumuraniun-t mineralsnrinerals • ~lineralSlvlirrerals =r--CompositionCortrpositiorr-----~------~~._------F.irn'uryPrimary I - -_.--ltu,.,t'utt)o;----- .j ------6------~ Uraniteljranite (l)I-, ' U,)t ) 0 21 , • .--_._+ I PitchblendePitchblcnde U,O~UrOs Becqllurelite8..qr',r',*lite Tuq.tut-,o7U02.11 H2O ' • - - - . I BarreneriteB^.erterit" (U,Ca,Fe,Th,Y)(Ti,Fe)2ttj,c r, r.Fti,\)( f r,F")zC), 0 c> • DaviditeDa"i,tite UFe5Tilj025Ue.rf,rO* I Coffinite U(SiO.j)I_x(OH).hU(SiOr)r.,_(OH).* • Secondary I uranophate Ca(U0Ca(UOz)z(SiO3)2(OH)2.5H2h(Si03)2(OHh.5H2zOO • sklodowskite (H30hMg(U0(FI3O)2M g(U02)2(Si04).211 2)2(Si04).2H22OO I schfoeckingarisclqoeckingaritete NaCa3(U02)(C03)(SO.j)F.10H20NaCar(UOzXCOTXSOT)F.I 0lI2O ----- • alltuniteautunlte Ca(U02h(PO.j)2.10-121120Ca(UO:):(l'Or)2.I 0- I 2l lrO ---_. ------I zellneritezeunente ClI(Cu(U0[JO:):(AsOr):. 2b(As04b·1I 0-12110- I 2l lrO20 ---'------,-". • torbernitetortlernite ClI(U0Cu(UO:)r(POr)2.2)2(P04h. 12HI 2ll?O 2O --- I saleeitesalccite Mg(U0Mg(UOu 2b(PO.jh.101hO):(l'Or)2. I 0l lrO _._------_.-. • camotitecam()tlte KK2(UO2XVOl).1-3H202(U02)(V04).1-3H2O -8 rII tyuyamuritelvuvamul'lte Ca(U0Ca(UOz 2)(VO.j).5-8IhO)(V O.r ). 5 ll 20 •T -- -.

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It 1.31.3GeologyGeolugy of0f Uranium It According tott-r thethe geologicalgcological setting,setting, the majorityrnajoritl'of of thethe uraniumuralrium resourcesresources inin thetheworldrvorld cancatr be assignedassigrrecl to one of the followingfollorving typestypes of depositscleposits2'6.2,6. II 1.3.11.3.1 lJLJnconlorrrritynconformity relatedrelatetl deposits It Unconlormity-relatedUttcottlbrrnity-rclateddeposits arise fromfronr geologicalgcological change occurringoccurrirrg II closeclosc to majornrajor unconlormities.uttcotrlbrnrities. Below Belou, thethe unconforty, thethe meta­nreta- sedimentaryscdirttcntaryrocks whichr,vhich host the mineralizationnrineralization are usually faulted and t brecciated. • Unconformity-Uncontbrrnity-related deposits constitute approximately 33%33% of the , I worldworltlUraniumUrattiurn resourcesrLrour.., and they includeinclu

• Nopa~ I Examples of this type are deposits of Michelin in Canada, Nopa$ in • Chihuahua Mexico, Macusani in Peru and numerous deposits in China I and the former USSR. I

t 1.3.10 Surficial deposits I This type broadly defined as uraniferroussediments,sedinrents, usually very young F to recentage that ltavehave not beendeeply buried and maymayor or ntaymay not been F calcificdcalcified to somedegree. The Uraniumdeposits associated with calcified sedimerrts,sediments, relerredreferred to as calcrete,rvhichwhich occur in semiaridareas of T Australia,Namibia and SornaliaSomalia are included with this type,also include T peats,bogs and Karst caverns as rvell well as pedogenic and structural fills. •:! .-F l I --I 6 I fll-r -.

Il 1.3.111.3.1I lVletasomatiteNletasornatitedeposits In this type uraniumuraniunrconcentratesconccrttrates in metasomatitesnretasomatitescommonly intruded ; I by microclinenricroclinegranites. ExamplesE,xarnples of this type are the deposits at Ross Il AdamsAdarnsin Alaska in the USA, Zheltye Vody in Kriroy Rog in Ukraine and Espinbarasl3sllinbaras in Brazil.

Il t l 1.3.12 Metamorphic Metanrorphicdepositsdeposits • This type occurs in metasediments and metavo1canicsrnetavolcanicsgenerally without I direct evidence of post metamorphicmetarnorphic mineralization. Example of this type •l is at fOt"stau,forstau.Australia. •I 1.3.13 Iigritesligrites deposits • This type is generally classifiedclassihecl as an unconventional uranium resource, l occurs in lignites. ExamplesE,xanrples of uraniferous lignites are located in the I • serres basin, Greece, in north andancl South Dakota and deposit at melovoe,melouJe, I Kazakhstan. •I • 1.3.14 Black shale deposits I UraniumUraniurnof this type of deposit also considered unconventional resources. • Examples: challanooga shale in the USA and chanziping deposits in •l china. T 1.3.15 Other type of deposits: • 'Ihis I This type includes the deposits not classified under the above deposits. • Examples are deposits in Todilto, l'odilto, Limestone, Grant's district, New I Mexico, USA. • 1.4 Uranium Uraniurnisotopes 238U,2lsu I Inln nature uranium atoms exist in several forms called isotopes 238U, 235 U ! • tiou. •I and 234 U. Intn typical natural Uranium, most of the mass (99.2739%) would t 7 •.:I Ii

2r8U. ; consistcorlsistof atomsatornsof 2J8 U.AA very small portion of total mass (0.7204%) 2r5U 230U. • consists of atomsatornsof 2J5 U andancl(0.0057%)(0.00 57%) consist of atomsatornsof 2J4U. The 11; t"U 2lsu 2J8 U isit a parent of uranium series (4n+(4n+2) 2) and 235 U is a parent of uranium actiniumactittiunrseries (4n+(4n+3;6.'l'hese 3t These series are shownshorvn in Fig (1.1)(l.l) and (1.2), I ' • respectivel/.respcctivelya. ; There also artificial Uranium isotopes produced in reactor by neutron t'ou, t"u, t"U, tIu 213u.'the • induce such as 236 U, 237 U, 239 U, 232 U and 233 U. The Table (1.2) shows the l a'6. • natural andancl artificial UraniumUraniunr isotopes 4,6. l 'table • Table (1.2):( 1.2):uranium isotopes l1lil isotope HalflifeHalflife AtomAtottt percents%nercentsTo SpecificSpccificactivity Bq/g 232)7)-"-u 72y72v U - - 233233u 5 l1lil U l.G2*10I .62*105 yv - - 234234u 5 0.0057 231.30 U 2.47*102.47*105yv 235235u 8 0.7204 80.01180.01I I U 7.10*7.l0* 10 108vy 236236u 7 • U 2.39*102.39*107yv - - 237237u 6.750 y IIIl U - - 238238u 9 99.2739 12.445 U 4.514.5tr * 10109Yy 239?39u 23.5 min t U - - I

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hI I I I n 8 rt •l I FigureIiigurc(1.1)(l.l) U.oanium-238Uraniurrr-238decaydecal' series: I '81' ;^j145Gy5 Cv ,f 123B?38U l e a 234?sThmrr I 1 . I " 25 d ' • The UraniurnUranium-238 .. 238 144t44I I. (}":"irjiDecay t··wt··r ill\i__ _.' ! I(25dr\6.7 h l DecayDocaySeriesSories ···-·t-'··-r-· _- --_.. ..- .. 234-pa-Nis;6.7 lr ··-.1----.------I - --- P

80XErj8,"txerJvalJesval':es o • 206?0sTI' • • 1·10140d - Lead·206Lead.206is the Tl ·-t I forlorhall-hIehail-lrle are 20fiPt' end roduct 1244.21244.2 rntn :- 206 Ph- stableslableend j, • forfc,rmultiplernultiple 8182 83 84 85 868786 87 88 89909192939489g0 9t 9293 94 8081B0 828384 pi-llhs It docayd*caypaths HgHgnTl Pb Bi8i Po AtAl RnFr Ra AcAcTh Th Pa U NpPu •T •I •I 9 •I E ql t FigureFigurc(1.2):( | .2):UraniumUraniunr ActiniumActiniunr decaydecay series:series: - .... -- - , I Beta • TheTheUranium·235Uranium.23S 144144 Decay I DecayDecaySeriesSeries t42 • i rl tm I ~2:.J5Ugr u Se~ssenes I I li 25h 232tttTh f40 ' 't,,.,. it • i On Th Seriesseries i | 32ky ?3t t 227 Pa 0:>38?38 ?1: Ac I n .--..-l .- I .UUSenes Senes 138 *t'-- • I i .. On ...."'1/il:l/NS. 223 I Nppenesserias zz 227 • ~ 136r36 l1>o I 'l J) ,t)rJ I The four naturalnaturaf DE ' 219 At . i t E 'l • radIoactiveradroactiveseries:::>series :) 13l3,l,1• .. 1 . 'f 223--- Rn .' HA c:c 215.~215 11 d ~~_ t c 81 co 1 I" r- • Thrs t- I 2199Rn ThIS seriesss6gsis;s el 132r32 j. , tizt Rn" I, e-tl 'I I ~fl I traditionallytrffCl't ron&l ly calledcnrleNUCLEAR FUEL CYCLE •IIII I t IIII •I •I •T •I .'I •I 11l

11l NUCLEAR FUELFUBL CYCLECYCLB

11JI- T 2.1 UraniumUraniurn mining:nrirring: t Mining is firstflrststep in nucleartruclcarfuelfLrel cycle and it carried out depending on • the oreorc depth and environmentalenvironrnentalconditions, through either open pit or -l'he I underground mining.rnining. The Fig (2.1) shows shorvsthe diagram of Generalized •I process for uraniumuraniunrextraction. • Open pit miningminirrgoperations,operatiorts, can be applied to sedimentary and vein type I ore bodies. And it used for near surfacesurlace deposits. Open pit mining is • preferred to underunder.ground,ground operation because a high productivity beller ore I recovery, easier dewateringdelvateringand safer mining can have greater •t environmental impact than underground mining.rnining. Underground mmmgmining • used forlbr depths from 50-200 m or more and the selected method and loading operation depend on the type of the ore. Safety is very important

tt • 2 • from radiation hazardhazarrj come fromlrom direct radiation,radiation. dust and radonradon2. • t t. •T 2.2 Uranium Uraniurtrntilling:milling: • The second step of nuclear fuel cycle is milling.rnilling.This step involves t crushing and grinding operation to produce a sized or suitable for aci9aciqlor • alkaline leaching. I 2.3 Uranium Leaching: • Leaching is an important step in the processing of uranium ore. The I 2 • leaching process controls the followingfollowing2: : IIII a) The proportion of uranium solubilized from the ore b) The quantities of reagent, which are major operating cost, required to IIII maintain suitable leaching condition. c) The concentration of impurities in leach solution. •t d) The grinding requirements.requirenrents. •I I 12 •L_I Il

t'u. II UraniumUraniurnores are treated by either acid or alkaline reagents 2,6. A lot of factorsf'actorsmusttnust be consideredconsidercclto select acidacitl or alkaline reagent such as IIII carbonatecarbotratccontentcontertt to ore, efficiencyel'ficiency of uranium extraction \vaterrvater usage, I energy consumption,cottsutnption, productprclduct quality requirements requirenrentsand environmentalerrvironrnental • consideration. Although acid leach is used in majority of uraniumuraniunrmills,nrills, t. t alkalinealkalirreleachinglcaching has numbernurrrber of fundamentalfunclanrentaladvantages these area.e 2: 'l'lte •I a) The solution is morerttorespecific for uraniumuraniunrminerals, leaving most of • thethcgangue unattacked. b) Uranium cah be directly precipitated fromlrom leach liquor. I 'ilre -- , c) The carbonate solution can be easily regenerated, 'I'hcse il These characteristics also lead to a number of disadvantages that include the following:

tI a. Fine grinding is required to expose the uraniumuraniunr minerals. b. Some gangue minerals (such as calciumcalciurnsulphate and pyrite) can * react with alkaline reagent resulting in high consumption. 'l'he I c. The more refractoryrelractoryuraniumuraniunr minerals are not dissolved under alkaline conditions. r 2 I After selection of reagent, there are five-leaching systemssystems2: : 1.l. Agitation leaching (acid and alkaline) il 2. Pressure leaching (acid and alkaline) 3. Strong acid pugging and curing (acid) II 4. Heap leaching (acid) l 5. Insitulnsituleaching (mainly(nrainly alkaline) fr The choice of technique depends on the above factors.lactors. 2.3.12.3,1Acid leach chemistryclternistry' of uraniumurartiurn t 'fhere There are two valency states in whichrvhich urat1lumuraniumoccurs naturally, the t hexavalent formforrn the oxide of whichrvhich is U0UOr.3, and tetravalent from,from. thetl-re

I I .-I 1313 ..t ..',

; oxideol' ,uvhiclris oxide of which is U0Uoz.2. In rn Hexavalentilexavalentformfornr uraniumuraniurn goesgoes directlyclirectly intoi'to t solution:solution: UO,+ 211'-+ UOz'.-+llzo (l) 'l'hc tctravalentgoes t The tetravalent goes intointosolutionsolutiorr afterafteroxidationoxidation toto Hexavalent llexavalentasas shown.shorvn. t U0UO22 ~+ UO/+UOrtt+ + 2e-2e' (2) (2) Thisoxidation ca4 t This oxidation car} bebeachievedachievecl byby ferricferricionion in in thetheleachleach solutionsolution asas givensiven byby thisthisequationequation

J 2 I U0UO,2+ + 2Fe2Fer*+~-r UO/Uor* ++ 2Fe2Fe2n+ (3) (3) To maintain 3 To maintain thethe dissolutiondissolutionofof U0Uoz2 thethe FeFer*+ must be renewedrenewedby t subsequentoxidaiion of Fe2*2 subsequent oxidation of Fe + formedformedinin eq.(3).eq.(3).Iftf manganese dioxidedioxide is is t used as thethe oxidant, thethe followingfollowing reactions taketake place.

2Fe2'+2 ~-) J 2 t 2Fe ++ Mn02Mnoz+ 4H+4H* 2Fe2Fe3,+++ MnMn2'+ + 2H2]lzo20 (4) 2Fe2r2 +l/3clor + ~ 3 2Fe ++ 1/3CIOJ + 2H+2Fl'-+FeFer* +++ 1/3Crl/3cl-++ HHuo20 (5)(s) +{. t 2 ~-+ 3 2Fe2Fe2*+ +H+HzSos 2SOs + 2H+zH* 2Fe2Fel*+ + HHzSoa+2S04+ HHzo 20 (6) The consumption The consumption of acid required to achieve the equivalent oxidation of +L ferrousis reducedby s0%. tf ferrous is reduced by 500/0. If sodiumchlorate or caro,scaro's acid are used insteadof pyrolusitein t I instead ofpyrolusite in theabove eq.(5) (6). By usingsulphuric acid in presenceof an oxiclizingoxidizing agent which provides t leach leach oxidationreduction potentials of 400-500mVmY relativeto saturated calonlcl t calomel electrode,being present in hexavalanceform as uranyl ion this t reactionoccurs: f Uort'UO/ ++ 2soq2-2S0/- -+~ LJo2(so4)2-U02(S04)2- (7)(7) t t--+ UO2U02(SO4)r'-+ (S04)/-+ SO.S04 2- ~ UO2(SO4)34-U02(S04)/- (8)(8) The uranyl t The uranyl sulphatesulphate anionanion cotnplexescomplexes areare species, species, rvhichwhich areare extracted extracted byby solvent. t solvent. UnfortunatelyUnfortunately thethe oxidizingoxidizing sulphuricsulphuric acidacid leach,leach, rvhichwhich is is o{tenoften t l414 nr--, L. •I l carried out at temperaturetentperatureof 40-80 QCoC is aggressive and non-selective • resulting in manyntatryother species besides uranium being leached!"leachedr. Thesel-hese t presentprcscntproblemsproblcrns in uraniumuraniunrsolvent extraction. SomeSorne of the mostrnost • l t important species involved arearer: : Soluble silica Si(OH)4si(oFr)4SiOsio2 z • , (W0 ) z· I TungstenI ungsten (Woo)t'4 r- • Antimony ( Sb0sbo44 )3. I ) ( As0 )3. • Arsenic ( AsO3)r'3 MolybdenumMolybdenurn (Mo0(MoOa)2'4/' 3 t Vanadium (V0(vo'')') 'l'itaniurn il Titanium (Ti0(t'i03)2-3{ ZirconiumZirconiunr ((ZrO)2'Zr03)2-

) 3- il1 PhosphateI'hosphate ( P0Poo 4 )'-

t In addition sulphuric acid dissociates in water as follow: 4 1 H S0 --)-+ HS0 . + H+ k =: 4x 10. il HzSOo2 4 HSO4- H* k 4x 10-r 2 HS0HSO+--+4' --) H+H* + soloSO+2- kk:= 1.27x I .27x10'210. il Chloride (Cr)(Cl-) and nitrate (NO)")(NO:-) anions may be present in the leach " I il Iliquorr.lquor . I 2.3.22.3,2Alkaline leach chemistrycherrristry of uraniumuraniurn The reagentrcagent used in alkaline leach isis carbonate and bicarbonate (sodium I - carbonate - sodiumsodiurnbicarbonate). In solution the uranyl ion forms stable t complex with carbonate ion, thus. -+ UOUOrt'zz+ + 2(C02(Cor)2-3)z- --) [UO[Uozz (C0(COr)r]''3hf (9) 2 UO + + 3(C0 )2- --)-) I Uort*Z 3(Co:)2-3 [UO[Uozz(C0 (Co:)r]o-3)3t (l0) (10) For reaction (1) iriid alkaline process, the hydrogen ion is supplied by , t bicarbonate, with inustmust be present for this purpose. t il 15l5 I •I l UO, + ll2O2-) UOr (I(ll)I)

• UO.,+ (('Or)r + 2(| I('Or + [U02(CO:dJ( + HIlrO20 (12) I )' [UO2(CO,),]'- • '| l 2.4 Purit1cationlturification t • A numbernunrberofol'rrrethods methods dependingdcpending upon type of solution can accomplish 2 -. thethcpurification of the clm-iliedclarilled leading solution. The variables includeinclude2: : a. Concentration of Uranium.Uraniunr. 'ilre b. The amountarrrountand concentration of impurities.irnpurities. '['he c. The desired final purity of thetlie uraniumuraniunrproduct. The leadinglcading solution compositionconrposition willrvill essentially be dependent upon the '['hus. mineralogynrirrerlkrgyof the ore, andattd leadingleadirrgmedium.nrediurn. Thus, a number of puripurificationtication combinationscornbinations maynray be applicable. applicable, For example, the 1. alternative can include the following,follorving,depending upon the feed solution 2 analysis and grade of productprocluctdemamleddemanded2: : 1.l. direct precipitation from alkaline and some acid liquors 2. Ionlon exchange, elution and precipitation. 3. Solvent extraction, stripping and precipitation. 4. Ion exchange followedfollorved by solvent extraction.extractiort.

2.5 SolventSolverttExtractionExtractiort The recoveryrccoveryof uraniumuraniurrtfromfi'ortr oresorcs by uSll1gusingsolvent extraction slI1cesince 1955 withrvith the use of diethyl hexylphosphericacidhcxylphosphericacid (DEHPA)(DEI-IPA) the (DAPEX(DAPE,X process) andattd since 1957 secondary or particularly the tertiary amines (the AMEX process) haslras beenbcen popularpolrular extractions. A commonconrnronorganic phosphate tri-n-butyltri-rr-butyl phosphate (TBP) is widelyrvidely used for separating 'fhe Uranium (VI) fromfronr co-existingco-existirrgelementselernents in a nitric acid medium. The 2'6. Fig.(2.2)Fig.(2.2)shows the -flow flclwsheet of purification by solvent extraction 2,6. 'fhe The distribution coefficient is considerably large over an acid range from pH 3-6 M nitric acid.

16l6 TheTheadvantage advantageofof, (TBP)('t'BP) isis non-volatility non-volatility(boiling(boiling pointpoint 289 289DC) "C)and alclits its stabilitystabilitywithwith concentratedc

DueDue toto thethe large large alkylalkyl groupsgroups ofof TBPTBp (C(cr2t{27o4p)HOP) thethe complexcomplex t 12 27 4 compoundsconrpoundsareare readily readilysolublesoluble inin organicorganicsolventssolvents (e.g.(e.g. kerosene).kerosene). TheThe 6 I distributiondistributioncoefficientcoefficient forfor the theTBPTBP extraction extractiorrisis givensivenasas6: :

I r,",) D_ luo,(rvo,)r.zra I D= (14( l4))

I Theapplicationappl ication of thelorvlow o[of nrassmass action to equation((13) l 3) gives I L, luo,(N o,) r.zrn rr.,, l ^=6 (ls)(15)

Where,Where, K K isis the.the, equilibriumequilibrium constant.constant. ThusThus thethe distributiondistribution coefficientcoefficient I finallybecomcs; finally becomes; K I D_ I [nq[,lrn\ (16)( 16) I FromFrom equationequation ( (16) 16) itit cancan bebe seenseen thatthat thethe distributiondistribution coeffiaientcoeffioient I increasesincreaseswithwith decreasingdecreasingnitratenitrate content.content. I t717 t FollowingFollowingextractionextraction thethe loadedloaded solventsolvent isis usually usuallycontactedcontacted withrvith aa scrub scrub 6 solutionsolutiotrtoto remove retnoveimpuritiesimpurities fromliorn solventsolvent priorprior toto recovery recoveryofuraniumof uranium6..

2.62.6Stripping:Stripping: r .-i AfterAfterscrubbing, scrubbing,thethe solventsolvent passespasses toto thethestrippingstripping circuitcircuit wherewhere uraniumuranium .­ isis recoveredrecoveredinin aqueousaqueoussolutionsolution byby contactcontactofof solventsolventwithrvith acidifiedacidified .. aqueousaqueoussolutionsolution suchsuch asas sodiumsodiunt oror ammoniumammoniumcarbonatecarbonate. . 2.72.7PrecipitationPrecipitation • TheThe resultresultstripstrip solution solutionisis treatedtreatedinin aa precipitation circuit,circuit, whichrvhich itit isis precipitated by ammoniaanrmoniaoror hydrogen-peroxide produce (yellow(yellorv cake)cake). .

-­ The 11 IIZOZ2°2 used for precipitation of uranium peroxide fromfrom strip solution .- after acidifiedacidifred by HN0FINO3toto pHpll3.53.5 inin 7070"CQC withrvithstirring according toto the 3 .. followingfbllowingreaction:

UO2(NO1)+tl2o2 +HrO -) UOUO4.2fl,O.2H ° + 2HNO2HNOr ( (17)17) 4 2 3 The UOUoois conv,ertedconvprtedto UOUo, by heating at 450'C or by reducing it by 4 3 by NurSrO,Na S 0 solution as follow: , 2 2 3

2NaSO0 +UO +H O0 ->~ NurSoOoNa S 0 *UO_,+UO +2NaOH (l(18) 223' 3' 4 2 246 3 8) By using anrmoniaammonia the yellow cake is precipitatedas anunoniumanUTIomum diuranate(NH4)U2O',(NH )U ° , which it dried in an oven at 100' C and then 427 6 clacinedat 350'C toto obtainUO,UO 6.. 3 .. • •.. r818 II

II FigFig (2.1):(2.t):CeneralizeclGeneralized processprocess forfor uraniumuraniuIllextraction extraction

II OreOre I I I1 I MiningMining I I V1 • CrushingCrushingandand grinding grinding I I I1 • LeLeachingaching I I • +1 I SoliclSolid -- liquidliquid • 1I Separationand rvashingwashing tailings I I I • 1Y I I'uriPurificationhcation and concentrationc

Il Fig (2.2): ScheluaticSchematic flowflorv sheet of purification by solventsolvent'~ II extraction. II I Feed solution to solvent extraction I .. II J Extractio : 1Raffinate I TonTo rvaste'aste or to • I Acidificatio I IScrubbinQScrubbins I- ffurtherurther •l I I St'StriDoinsnOOIlH!.II Na..,C0l.NarCO. • StrippedStrillpedsolventsulvent I

I l\ Nil'} .I • PrecinitatioPrecioitatio ": I •,I I I U.oroductU. oroductI (NH4)2U2O7 II I •I I •11I •I •t •I 20 •I ; II I 11I 11I .­I ~I ..I, I • ,, CHAPTERCFIAPTER THREETHREE •I il LITERATURE REVIEW

*

*

Ii I t

II

II I I I •I I LITERATURE REVIEWREVIE\V -- 'fhere t There are nlanymany studies have been conducted on extractionof uranium. El-tlazekEI-Hazek arrdand El-Sayed ( 2003)r2003)3 have proposeclproposed a new liquid emulsion t llcnrbrancmembrane (t.[,M)(LEM) proccssprocess lorfor urarriutnuranium extraction from eitherdehydrate l 1 28-3028-30"/uYu I'zOsP20S (DII)(OH) or hcrni-dihydratehemi-dihydrate 42-45oh42-45% P2O5(HDI'I)P 20s(HOH) rvetwet process t plrosphoricphosphoric acid. lnIn this proccss,process, the organiccomponent of the LE,MLEM is t cornposedcomposed of a synergisticntixturemixture of 0.1M0.1 M di-2-ethylhexyl phosphoric acid (OEHPA)(DE,FIPA)and 0.025M0.0251v1trioctyl phosphine oxide (TOPO) withrvith 4% 'l'hc i Span 80. The internal or the strip acid phase is composedcontposedof 0.5M citric 'ftre I acid. The preparedLEM was provedto be stable in 42-450/042-45o/oP20SPzOs acid concentration rangerarrge , and can, therefore,lherefore, be applied to the phosphoricacid il producedby the hemi-dihydratehenri-dihydrateprocess. After breakdorvnbreakdown of thetlre loaded emulsion, the uranyl citrate in the internal strip phase is separated by adding methanol followed by its calcination to the orange oxide. Most of the reagents used are recycled. The proposed process is characterized by simplicity, practically closed operation cycle in addition to lower capital and operating costs.

Awwad (2002)15(2002)'s useduserlTOPO to extract uramum uraniurn(VI)(Vl) fromfi'om aqueous nitrate medium, it was found that uranium extraction by TOPO was suitable in toluene as diluent than cyclohexane cvclohexaneand chloroform. Sodium hydroxide solution is suitable for striping uranium from TOPO in toluene. Mohammed and Eltayeb (2003)16(2003)t6 used 25%TBP in kerosene to extractexffact uranium from Uro phosphate ore. For this thispurpose first, the thephosphate ore samples have been decomposed withrvith sulphuric acid. The resulting phosphoric acid has been filteredfilteredoff, and pretreated with pyrite and activated charcoaLcharcoal.The chemical analysis of thethe obtained grain phosphoric acid showedsholved thatttrat aboutabout9S% 98% of uraniumuraniunr

2222 ContentContentofof the phosphate oreore was renderedrendered solublesoluble inin thethephosphoric acid.acid. A three thrcc stagcstageextraction extracticlnatat aa phase ratioratio (aqueous/organic)(aqueous/organic)ofof 1l:2,:2, followedfullowcdby twotrvostagesstages strippingstrippirrg using 0.50.5 tvl N,lsodiumsodiunr carbonatecarborrate solutionsolution at a phasepltascratio (A/O)(A/O) of 1:4l:4 have been foundfound toto be thetlre optimumoptinrunt conditionscorrditionsto report morentore than 98%98",'"of uranium content 111in green phosphoric acid to thethc aqueousaqLreoLrsphase as uranyl tricarbonatetricarbonate complex

(U0(UOz2 (COjh)(C'Or)r)By tly applyingsodicasoclica decompositiondecornpositiorr upon thctlre stripping carbonatecat'bonatcsolution usingusirrs 50%5091, sodiumsocliurn hydroxide,hvdroxide. about 98% of uraniumuraniunr contcntcontcrrtwas precipitated[)recipitatedas sodiumsodiunrdiuranate concentrate (Na2(Naz UUz 2 0Or).7), The chemicalclternicalanplysis using atomicatonricabsorption spectrometry (AAS) showed a good agrcementagreementbetweenbetrveen the specifications of the obtained uraniumuraniutn concentrate withlvith the standard commercial specification of sodium diuranate concentrate. Further purification was achieved for the yellow cake by selectives"electiveprecipitation of uranium from the solution as

uranium peroxide (U0(UO4.2l'l20) 4.2H 20) using 30% hydrogen peroxide. Finally the uraniumuraniurnperoxide precipitated wasrvas calcined at 450 degree C to obtain the orangc powderpowcler uraniumuraniunr trioxide (UO(UOr).The j). The chemicalchernical analysis of the final uraniumuraniututrioxide product has proved its nuclear purity and meetsnteetsthe

l standard commercialconlnrercial specification. According to the obtained resultsresults', , it can be concluded that nuclear grade uranium trioxide can be successfully produced with an overall uranium recovery percentage of 93%93o/ofrom Uro phosphateore.

EI-KamashEl-Kamashand E1-SayedEl-Sayed(2003)s(2003)5 used extractionchromatography to studythe extractionoIof both U(VI) and U(lV)U(IV) frornfrom nitric acid solutions using'l'BPusing TBP solvent impregnated polyacrylic acid polymer (SM-7) as inert supportingtnaterial.material. BatcltBatch kinetic and breakthrough columncolunm experirnentsexperiments were carriedout to explain tliethe nrechanisticmechanistic aspects of the extraction processobtain therrnodynarnicthermodynamic parameters and simulateits applications.

23 Based onor-r thethc experimentalexperinrentalresults.results, an approximate and simplified first order kinetic expression haslras been used to interpret the metal depletion in the liquid phase. A mathematical mathernaticalmodel,nrodel, consists of metalnretalion mass transfertrattslerand columncolunur massnlass balance equations, was\!'as proposed to predict the breakthroughbreaktlrroughcurves of both metal ions on an extraction column. The predicted breakthrough curves were in a good agreementagreententwith the ExperimentalExperirnentaldata'.clata'. These results suggested that the proposed models are applicable to the interpretation ofo[ kinetic data, the prediction of breakthrough curves and can be used as design tool for extraction chromatographicchromatographic process.

Thompson ( 20022002)7 used useclsolvent extraction process to recover uranium and technetiumtechnetiurn fromfronr solutions of irradiated commercial reactor fuel whilewlrile sending the plutoniumplutoniunrto wastervastewithrvith the fission products and higher actinides was tested with actual fuelluel solution. HeI-le found the process meets

all goals for recovery and decontamination. Babain et al (2001)8 usedusecl gas$as extraction of actinide complexes withrvith beta-diketones prepared beforehand and analogous ones synthesized in-situ. Ittt was detennineddetermined that tributylphosphate in supercritical carbon dioxide can to extract macroquantities of uranyl nitrate efficiently. Experiments on preparation of uranyl complexes in-situ showsholv that in the case of low excesses beta diketones do not permit to extract uranium fromlrom uranyl nitrate. In the same time uranyl carbonate is extracted efficiently by fluorine-containing beta-diketones in the same conditions. Introduction of additional neutral ligand permits to increase efficiencyelficiency of extraction. Introduction of pyridine into solutions of beta-diketones in supercritical carbon dioxide leads to increase of uranium extraction efficiency from uranyl nitrate and does not affect on uranyl carbonate extraction. Data obtained confirmed

2474 thatthatbasicbasic functionfirnction ofof pyridinepyridineisis binding bindingofof nitricnitricacid acidescaping escapingduringduring formationIbrnrationofol' complexescorrrplcxes ofofbeta-diketones. bcta-diketones.

PugetPtrgctetet alal (2002)9(2002)e usedusedsolvent solventextractionextraction processprocess forfor treatingtreatingaa wastcwaterrvastcwatercontainingcotttaining dissolveddissolved uraniumuranium is is considered.considered.TheyThey usedusecl AluminaAluntina336336 (a (a~llixture qrrixtr-rreofof tri-octyltri-octyl andand tri-decyltri-decyl amines)an'rines) asas extractantextractant inin '['he thistltisprocess.process. The resultresultshowedshowed thatthat itit isispossible possibletoto reach reachanan efficiency efficiencyofof aboutabout95%95u/u forl'or thethe uranium uraniuntextraction,extraction, forfor metalntetalconcentrationconcentration inin thethefeed feed ofof 10l0 ppm.ppnl.Furthermore, Furthermore,anan efficiency effrciencyofof aboutabout50%50% is is reachedreachedforfor metalntetal concentrationconcentrationinin thethefeed feedofof II ppmpprnwhenu,lten thethe liquidliquid flow florvraterate isis equal equal12001200 L/h.Lih.

Zil'bcrmanZil'bcrntanetet al al (2001(2001)r0used)10 used 30%30% tributylphosphatetributylphosphate (TBP)('fBIr) inin dodecaneciodecane underttndcrconditionscorrditions of thethesecond secondorganic phase toto extract uranium(uraniurn(4) 4) andancl uranium(6)uraniurrr(6)fromli'onr nitric acid solutions. By comparingconrparingextraction for \he elementselemetttsforlor similar conditions,cottditions,when using non-stratified extraction systemsystenl(300/0(30% TBP in hexachlorobutadiene), it was shown that during uranium extraction fromlrom aqueous phase for both systems noticeable differences are pointedout. Study of absorption spectra of the light and heavyorganic phases suggested the assumption that solvate forms in both organicphases differ both for uraniunturanium (lV)(IV) anduranium

Cao et al (2002)"(2002)11 have proposedflorv-sheetflow-sheet for obtainingyellorvyellow cake fromfrom Sandstoneores corttainirtg containing uraniunruranium in NongNong Son areato to recoverrecover 'l'hese uraniunruranium in thethe fiortnform of MDU.MDU. These oresores havehave beenbeen classifiedclassified intointo 3 categoriescategories dependillgdepending onon tltethe u'eathcring weathering degree,degree, givinggiving differentdifferent chenricalchemical

compositioncomposition asas shorvn.'l'he shown. The arnountamount ofof calciurncalcium carbonatecarbonate (g(g CaCO3CaC03 /100g11 OOg ofof ore)ore) reactedreacted withwith HCIHCI underunder different different conditionsconditions ofof ternperaturetemperature andand timetime showedshowed that that stirrings,tirring rnettrod method requiresrequires highhigh acidacid consumption.consumption. TheThe resultsresults obtainedobtained fromfrom staticstatic leaching leaching ofof thethe 33 oreore categoriescategories showedshowed thatthat

2525 leachingefficiency largely depends on the weatheringrveathering degree and particle 'l'he size of ore. The lowest leachinglcachingefficiency was observed for non­non- I weatheredweatltcredore.orc. In order to increase uranium extraction this ore was I groundgrourtdto thetlrt:size of max. 2.5rmn,2.5nrrn. andarrd then incubatediricubated by 40%40"toHHuSOa 2S04for 48 hourshoLrrswith the addition of KCIOKC'lO3 (3 kg/tone of ore) as oxidant. The I results of acid pugging showedshorved that uraniumuraniurn extraction efficiency reached

min.min.92u/u92%. The leaching experiments 'Nerewere carried out under the following conditions: Particle size of ore: Weathered: max. 30mm, Semi-weathered: max. 10mm,lOmm,Non-weathered: max. 2.5mm (incubated by 40%40% I-hFI2S04);SOa); 'l-empcrature Temperature 25-30 deg. C; Redox potential; pH I,l, acid consumption: 40­40- 50 kg/ore tone. Leaching efficiency reached 90%. Uranium concentration in thetlre solution after 8-stage counter-current leaching was min. 4 g/L,glL, uraniumuraniunrcontentcontcnt in solid wastervastc 0.00.0l%r. I%. LeachingLcaching solution was filtered and directly neutralized through twot\r,o stages to precipitate yellowcake. ExperimentalExperirnentaldata showedshorvedthat the uranium recovery reached 90%.

YellowYellorvcakecake product metnret the relevant specifications and had UUlOa 30 8 content of minimumnrininturnT6u/u.76%.

FyodorovFyoclorov(2002)12(2002)r2 used In[n Situ Leaching (ISL)(tSL) method to production • uraniumuraniurnfrom open-pit and underground mines in Kazakhstan; they found this method has a number of economical and ecological advantages. Faizal et al (2000)13(2000)rrused solvent extraction TBP/ kerosene to Rirang ore uranium extraction to produce ADU from rare earth and they recovered

98.75 %u/o of U with yellow cake (ADU) whichrvhichcontents U =: 67.55 %o/o andand : RERE2Or20 3 = not detected.

Wisnubroto (1997)14( I gg7)t4used diethyl hexyl phosphoric acidacicl (HDEHP) and Tri-octylamine for U recovery from sulfuric acid solution and he found I that the later compound is easier to use, and also has a good selectivity on recovery ural1lum.uranium.

26 ConclusionConclusion

BasedBascdon on thisthis reVIewrcviervonon extractionextractionandand purificationpurificationofof uramum uranium concentrateconccntratc(yellow(yclloiv cake)cake) fromfronruraniumuraniurn oresores thethe belowbelorv concludingconcluding pointspoints I cancanbebc drawn: drawn: I.l. OpenOpenpitpit miningminingisis preferred preferredtoto under undergroundground operationoperation becausebecause aa high high productivityproductivitybeller bellerore ore recovery,recovery,easiereasier dewateringdewatering andand safer safermining mining cancanhave havegreatergreater environmentalenvironmental impactimpact thanthan undergroundunderground mining.mining. 2.2. AlkalineAlkalineleaching leachingisis preferredprefenedforfor highhigh carbonatecarbonaterocksrocks because becausethethe solutionsolutionisis moremorespecific specificforfor uraniumuraniumminerals,minerals, leavingleaving mostmost of of thethe ganguegangueunattacked,unattacked, uraniumuraniunr cancan bebe directlydirectlyprecipitatedprecipitated fromfrom leachleach liquorliquorandand thethe carbonatecarborrate solutionsolution cancan bebe easilyeasily regenerated.regenerated. 3. Acid leachingleachingisis preferred over alkaline leachingleaching forfor lowlow carbonate rocks and morentore refractoryrelractoryuranium mineralsnrinerals which,rvhich, not dissolved under alkaline conditions. 4. Particle size about 2.5 mmmnt increases uranium leaching efficiency and suitable for filtration.filtration. 5. Potassiumchlprate used as an oxidant is very efficient in increasing leachingeflficiency.efficiency. 6. In Situ Leaching(lSL)(ISL) methodis superiorover other methods because it hasa number of economicaland ecological advantages. 7. TBP isis consideredthethe mostsuitable extractant for uraniumbecause itit isis non-volatilenon-volatile and stable rvithwith concentrated nitricnitric acid. 8. KeroseneKerosene isis thethe most most widelywidely usedused diluent becausebecause itit isis easilyeasily availableavailable andand inexpensive. inexpensive. 9.9. HydrogenHydrogen peroxideperoxide IS thethe bestbest precipitantprecipitant becausebecause givesgIves moremore purepure product.product. +

2727 ReferencesRe[e rell ces

I.t.M.M. W.w. Makenzie:lVlakenzie:UraniumUraniurn solventsorvent extractionextraction usmgusing tertiary tertiary amlllesarninesUranium uraniunr oreore yellow yellorv cake.cake. Seminar,seminar, MelbourneMelbourne AustralAustraliaia (1997).(1997).

2.2.IAEAIAEA(1993): (1993):UraniumUranium extractionextraction technology,technology, TechnicalTeclmical reportreport seriesseriesNo.No. 359,359, Vienna.Vienna.

-t 3.J. E1-Hazek,-N.T.;El-lIazek,-N.'r.; EI-Sayed,-M.S:El-Sayed,-fvr.S: Directtf irectural11um uraniunrextractionextractiorl fromliorn dihydratedihydrateandand hcmi-dihydratehenri-clihyclratewet\\,et process processphosphoricphosphoric acidsacidsby by liquidliquid emulsionemulsionmembrane.ntenrbrane. J.J. Radioanalytical-a~ld­Raclioanalt,tical_arrrcl_ Nuclear-Chemistryl,'luclectr-CltentistryV.V . 257(2), 257(2), 347-352347-352 (2003)(2003 ) 4.4. InternetInLernetwebweb sitesite www.uic.comrvww.uic.com 5.5. EI-Kamash,-A.M.;El-Kamash,-A.M.;Ei-Sayed,-A.A.;L,i-Sayed,-A.A.; Aly,-H.F.Aly,-H.F. ThermodynamicsThermodynamics ofof uranium extractionextraction fromfrom nitric acidacidsolution solutionby TBPTBp loadedloadett on inertirrertsupporting material. Journal of Radioanalytical-and­Ratlioanalytical-and- Nuclear-Chemist,)'.Nucleur-Chemistr.y',V 2532S3(3) 489-495489-495(2002).

(L6. NasscrNasser S.s. Z.:Productionz.:Productionof YellowyellorvCakec'ake from Rock Phosphatephosphate <'s&It's Characterization,M.Sc.'r'hesis,M.Sc.Thesis, Karary AcaclenryAcademy of l'echnology,Technology, Sudan (2004 ).). 'l'hornpson,-M.c: 7. Thompsoll,-M.C: DenronstrationDemonstration ofof thethe uREXUREX solventSolvent ExtractionExtraction ProcessProcess rvithwith DresclenDresden lteactor Reactor FuelFuel SolutionSolution (Report),(Report), (2002\.(2002).

8.8. Babain,-V.;Babain,-V.; Kantachev,-V.;Kamachev,-V.; Murzin,-A.;Murzin,-A.; Shadrin,_A:Shadrin,-A: SupercriticalSupercriqcal gasgas extractionextraction of of microquantitiesmicroquantities ofof metalsmetals byby beta-diketonesbeta-diketonesRussianRussian FederationFederation (200(200 1 I).). 9.9. Puget,-Flavia-P:Puget,-Flavia-P: AltemativeAlternative processprocess for for treatingtreating radioactiveradioactive effluents.lnternationaleffluents.Internationalnuclearnuclear Atlantic Atlanticconference conference(INAC);(INAC); 13.13. BrazilianBrazilian'(2002).(2002).

2828 IO.zil'bcnnan,-B.0.Zi I'bcrnran,-8. Ya.;Ya.; Fcdorov,-[;ed.rov,-yu.S.Yu.S.;; Arkhipov,-S.A.;Arkhipov,-S.A. ; Blazheva,­BI azheva,- I.V.;Glekov,-R.G:I.v.;clekov,-R.G: 4 G ExtractionExtractio.of UUa'+ andanclUU6* + underuricler conditionsco.clitions of thetlresecond organicorgarric phase formationfbrrnation J. Radiokhimiya.,Rartiokhi,rit,o..V.v. 43 (2) 155-159(2001).lss- | se (2001 1. I I.Cao,-H.T.;I.Cao,-lI.1'.; Le,-Q.T.;Le,-Q.'l'.; Dinh,-M.T.;Dinh,-M.'l'.;1'han,- 1'han,_V.L.;V.L.; Le,-K.D:Le,_K.D: UraniumUra.ium leachinganda.d recovery fromfrorn sandstone ores of Nong Son BasinBadirr (Viet(viet Nam)Nanr) Internationallnternationalsymposiumsymposiurn on the uranium productionproductio. cycle and the environment, Viennavienna (2000). 12.Fyodorov,-G.V: l2.Fyodorov,-G.V:UraniumUraniunr production and the environment in Kazakhstan (Report); K.r. The uranium productionproductio' cycle and the environment.envrronment.Proceedings 571 191-198l9l_l9g (2002). 13.Faizal,-R;I 3.Faizal,-R;Hafni,-L.N.;FIalni,-L.N.; Budi,-S.; Sugeng,-sugeng,-w.;susilaningtyas: W.;Susilaningtyas: Rirang uranium ore processing using base methodmethoclwithrvith purificationprrrilicationof uraniumuraniurnhydroxidehydroxitle from fi-onrrarerar.e earths . FifthFiftlt ScientificScictrtiJicPresentationPresentotiotr onotr NuclearNucleqr FuelFttel Cycle:C),cle: Nuclear Fuel I Elements DevelopmentDevelopnre.t Centre,centre, National Atomic Energy Agency 332 102-108102-108 (2000).

14.l4.wisnubroto,-D.-S:Wisnubroto,-D.-S: Uranium extraction from suIfuricsulfuric acid solution, National Atomi Energy Agency, Serpong serpong Indonesia (212)(2r2) 6-126-12(1997).(1997\.

15.Awwad,-N.S:l5.Awwad,-N.s:Equilibrium and kinetic studies on the extraction of uranium (VI)(vl) fromlroln nitric acid medium into tri­tri- phenylphenylphosphi'ephosphine oxide using a single drop column technique. 1.J. Nuclcar-Scicnccs-and-Applications,Nucleur-science.s-urtd-Appticatiorts,V.v. 36 (3)(3),151-160,151-160 (2003(2003))

16.l6.Mohanrnred,-A.-A.;Mohammed,-A.-A.; Eltayeb,-M.-A.-H: Uraniumuraniurn extraction from Urouro area phosphate ore, Nuba mountains, Sudan .6.6,h th Arab conferenceconlerenceon peaceful uses of atomicatonricenergy Cairocairo (Egypt) (2003).(2003).''

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