B.A.R.C.-636

<«

GOVERNMENT OF INDIAATOMIC ENERGY CbMMISSION

- EXTRACTION OF NEPTUNIUM BY TRILAURYLAMINE

-by , r - .

S. K. Patil, Rajsndra Swarup, Mr V. Ramaniah and N- Srinivasan-. — - - Radiochemistry Division

BUABHA ATOMIC RESEARCH CENTRE*

BOMBAY, INDIA

1972 •*

B. A. R. C.-636

3 GOVERNMENT OF INDIA? ATOMIC ENERGY COMMISSIONU

EXTRACTION OF NEPTUNIUM BY TRE..AURYLAMIHE

by

So K. Patil, Rajendra Swarup, M. V, Ramaniah and N. SrinivaaanRadiochemistry Division

BHA.BHA ATOMIC RESEARCH CENTREBOMBAY, INDIA

1972

ABSTRACT

Trilaurylamine (TM) i B considered as useful solventfor ths final purification of plutoaiusa and neptuniumo As TLAi s considered as an alternate poaoibla extraotant for tho finalpurification of plutonium and neptunium at Texapur ReprocessingPlant under construction^ i t was considered necessary to studyths optimum conditions for the extraction of neptunium using TLAe

Experiments were oacrisd out on the extraction ©f

into 2Ofa TL1 i n Solvesso-100. IIIQ dependence of the extraction of

Kp(iv) on (a) n i t r io aoid concentration from i°8M, (b) neptunium

coacentratiosa from 1-25 ug/ml (o) uranium concentration ranging

froB 0 °> 300 mg/tsi.t has been studisds The extraction of (

from ?M ni tr io aoid aaing varying ooncentration of T1A

studied and the log-log plot of distribution coefficient vs T.TA

ooncentratioa was found to ba a straight line T<dth slope 2= The

effect of diluent on the extraction of Hp(lV) into T1^ waa also

studiedo

The stripping of neptunium from the TIA phase was found

quit© satisfactory with a oistura of 1 5M sulphurio acid aid

0«5M nitr io aoid» 1M formic or acetio aoid and 0.5M perchloric

aoido

EXTRACTION OF NEPTUNIUM BY TRILAURYLAMINE

by

S. K. Patil, Rajendra Swarup, M. V. Ramanlah and N. Srinivasan*

1, INTRODUCTION

Long-chain high molecular uoight ansinsa found a wide application in

nuclear process chemistry for the selective ©ztraotion @f m9tal ieataj, purifieatiea

@f fertile End fisaila aatorials from irradiated fusls and isolation of treas-

plutaaium elenraatse Amino @zt?aoiion of aoids and of metal ion oomplosoo woa

first saportad by Smith and Page in 1948 e In 1957e Sheppard ^ demonstsatsi

th@ high sztraotion powsr of a tertiary amino for ftp(XV) and Pu(lV) aitrategs

Wilsea"' esteaded Sheppard's study and his wozk aroused widespread interest

ia plutonium(XV) nitrats ©Ktraetion Tdth tertiary amines g especially trilauxyl°

(TLA) io considsi-sd as usoful solvent for the final

purification of plntonitus and neptuniums The ohlef advantages of using T1A as

aa ©stsaetent ar® (i) high selectivity in extracting neptunium and platosius

from nitsio aoi& madiua over a large rango of acidities (ii) high astraoting

lowas aoiditiss as compared to most other eainsG^ (iii) adaquato

fros irapuritiss (ivO favourablQ eh&aioal sad physical properties

as high boiling ead fr@@sing points; low density» low solubility ia oatar

ami good rssistaraoo to acid an$ radiation (v)''availability in ralativoly puso

ia

- 2 -

Because of its remarkable properties, trllaurylamine was used

ea oft extraotant for the final purification of plutonium in the reprocess^

ing plants at Marooulew/ and at Cap de la Haguev <. Champion and

Chesne" ' reported the extraction of Np(lV) by TL& in a-dodecane from

nitric acid and the stripping by sulphuric aoid -nitric acid° Reoently

Eathellier and Coworkers* describad a oountor^ourrenfc process for th@

co-extraction of neptunium and plutonium by 20$ T M in dodsoane from ths

wastes of the irradiated fuel processing plants» They also studied the

separation of neptunium and plutonium by selective extraction of

neptunium into T I A ' 1 1 ) .

2. P R E S E N T W O R K

AB TLA. 1B considered as en alternate* possible extraotant for

the final purification of plutonium and neptunium at Tarapur Reprocessing

Plant under construction^ it was therefore considered necessary to study

the optimum conditions for the extraction of septuaiura using TIAO From a(12)

literature survey on the extraction properties of TLAV '„ it was found

thcfc aromatic solvents are by far the most suitable diluents for the

amine compared to aliphatic solvents because of the higher solubilities

of amine Baits and the metal complex in the former solvents. la ths

-present study, Solvesao-100 was used as the diluent as this la likely to

be used at Tarapur Plant. This report describes the following aapeets

of the Kp(lV) » T M extraction systems-

Effect of the TL& aenoantration

Effeet ©f nitsio aoid oa the 2L& sstraetiea of

Effeat of usaaium(vi) concentration on thoextraction of IfpUV) by TU.

Effect of diluent

Stripping of naptuniuin(lV/ from 3?LA phase by gagents suoh as (1) eulphyrio acid and nitrio acidmixture (?.) formia aeid (3) aostio acid and (4} psrchlorieaoii '

3. EXPERIMENTAL

3. 1. Materials

Heptunitso<°237 ^@s obtoined from Oak Mdgo National Iaboratorjr,, USA

in th© fosaa of @pOg Ehiol* ©as

each t i so fsom isradiatsfl natural raaaium bjr W& estrsctioa» 1'!^ obtains^

E & K Laboratories Incoe USA was ussd without further purification as i t

found to bs of sufficiently high purity o SOIVSBBO-IOO tms supplied

"Ess© StamdsKd COffipan3r"E Holland* Stock solution of uranium!'Vl) ni tsats ma

by dissolviHg sue? ? purs uranium osido i s AoRe n i t r i e eoid sad

eoatsnt v&a astimated vcluiaGtrioally

The acidity of the uras^-1 aolutiea^ms dotsEminad after oosaplesins usaaiua

td/lh esalaft© 'e All the othoj? choiaieala ana raagQnta uood was© of Aol geado

sseagt f@£seus sulphamats whlete ^aa psspasad frcs(19)

% ths taathicd Sesoslli@d by Enohwrn) "c

3.2. Pgqcedure ',

I©gtmsi\im»g37 -siaa pasifiod Sscm it@ iEUght©B auelite " P a

of the la i te? from ?M aits lo eel i

to I t lit order to facilitate the estimation of nsptkaium by gams say eeantiag<>

Ferrous sulphainate ( 0,1 H ) was used as a holding 'sedueteat to keep neptunium

aa 8p(lV)6 in all the experinanta the 2**Np eOHQsatsatioa ma kept at ©beat 2-3

ug per mi* 2OJ6 MA in SolveBBQ=>1GQ (vA) was used la al l the ffspoziaontse

3.3. Extraction Experiments

A suitable aliquot of the BpU?) tracer was added to a 5 ml of

e^uaoua phase containing the deslrad conosntratioa of oifeie eoii ©ad 0»1 M

farrous sulphamatOo J s equal volims of 20$ ?M in SolvaoBO=100 pr@«®tuilibsat©i

with nitrio aoid of th« required eonaentration was added and was then shaken for

10 ninutaa using a Vortex miser* I t was centrifuged and aliquota froa both the

phases ware counted in a woll-typa Hal(ffl) ^ -eointlllation oounter*

3. 4. Stripping Experiments

Haptuniu&Cl'iO m® ©st^otet into ZOfa TM in SOITOSBO-IOO Sstm 2 I

nit»io aoid solution* 2 ml of the organio phao© wa@ eontaotsi with 2 s i of the

aqueous phase containing the stripping agent of knom eonosntsation aad 0001 1

fesxous eulphamatfr ($•** «ss added to ensues the tetravalenoy of mepttmi^a

during stripping) and r^a shaken by slow rotation foe eao he«s Binoa this tin©

was found to be ade^uat* in attaining the equilibrium* Hiquots from bothths

phases were counted at the end of equilibration*

4. RJESULTS AND OBSERVATIONS

4.1. Extraction

sxpajeioanta showsd that the oxidation statd of

<3id not ohsnge lieos Dp(iv) §us>ing i t s ostsaotioa into ^M t&an ©ithar 0«O1

©ulplioEat© was used as hoiaiag seductaato fhi® ma ohaekefl

by testing the oxidation stat* of asptnaium ia tha aquaoua phase bafag© asd

after the extraction by MA uaisgj SHBA ©stEaotien msthedo It mm ssacantly(1B)

that the sstraetiwi of Eto(lV) into SM was ©law aad tha q

attained only Biter 10 zalautos although i t was obaGsrvad by RolaaSi st

that tAe @qailib£ium was attained la about a talnat©' K I t wa§

oonelS@z@a desirable to asrlfSf tkiso The kiaetios of QStsaotiea ef

was followed ia 3 S isitsio acid tho rosuUbo of ^lioh shoraod that th@ ®<3.u£librlm

was attained in 1»2 xisutaSo How@v@r; the aquilibrctioa sas oaKsrisd oat fos

10 adnatas in all the estssotioa scpaBimsatSo !Ki© distsibmtioa ©osffioioat

value obtained by taking Hp(lV) activity ia eithsx- phoeo was fo'aai to bo th@

sens indioating tb© EOT© rsttility of tte Qjrstoso Ths distsibatioa oesffiolsat

Q£ lp(SV") w&g also fonaS to Isa iMopeMo&t of th© aoptuaiua' aoaeoatsatioa ia

tho mass 1°25 m/mk iah&9Ssi§ that onty moaoaaoloaff a@seios Q£6

4.2, Effect of TLA Concentration

5b® estEaotion of Ip(SV) ism 3 1 aitsle aoid ^ith ms&tng

tioa of SM. uao atuii@S« 52iQ log°log plot @f thQ dlQtglbstiea eooffioioat

M eoaoantratioa was fouaS to te a gts@ight lies cith a slofe of

. 1)O Ste^naoa eM ffeig©' ' eosaeotea tho ©stsaotioa of

SM. tak®@ pleae pgQSBaabiy ^m. tho fOEsa&ieia of oa

^g (1)

teite ©te©Q ssoojeflini t® ©la&tiea (?)•

- 6 -

Both these •eohanisBS suggest that the dietelbutiea coefficient of

varies with the leooKi power of 3SA eoneentsatioa as found

4. 3. Effect of Nitric Acid Concentration

Apart frea BOOS results obtained for plutonius by ColeBC&v^% Fas

Gael ^ and Kcaar at al » ao qpantiteti^e data as® available on th© ©3txae°

tien of ths actiaidesg partieulaely neptunium Sss the @£Sfc®sa EM-SO1TOSSO»10Q

HNO,-^O. The variation of the distribution coeffioient of Hp(iv) with the

nitrio acid ooneeatratioa i s shorn in Pig. 2 . fhe values for Su(l^) for the

sane systea taken from l i terature' 2 ' ' ere also plotted for comparison. A broad

iaxiana around 4M HNO, was observed for both neptuuiua and plutonitwe

values fop fe( lv) are hijiei? thea for Sp(iv) by a factor of 4-5. at a l l the

acidities* Ifhis agrees with the tssad of ths results obteJ.asd fey EQdas'at e l

for Hp(XV) ami Pa(l^) nith TOA in sylenao $fc© dGGSoaas of ostsactnbility at

she higher aoid concentration aay be attributes to ths fosmstioa of the highs?

oonplex or uncharged complex saatal aoide of the tjpQ ^Hp(K0_)gO fh

•ight at least partly be also due to the deoreaee of aitmte ±ms at

oonoentration of aitrio aoid or due to the competing effect of the

present ia the organie phase*

4'. 4. Effect/of Oraniuni Goncentration

i s tho feed solution for the final pasificati«a of neptunium in

Bixex process ie liksly to eonteia soae U£aaim(^

of 3 gA)» i t van cooiidered nsoaasasy to atud^1 the ©ffsat of

-7 -

on tht distribution oeeffieiant of Np(lV)0 g]h@ distribution coefficient of

Np(lV) wag determined as a function of W(Vl) ocnoantratioa (0-500 gA)» Eho

data given in Table 1 show that xhe distribution coeffioiant of Hp(lV)

decreases with increasing U(V£) oonoentrationo ThiB trand is similar to tha

observed in tho estrastien of Pu(iv) with diffasant amines^ ' ''. The

diatsibution coaffioioat of tj(^) in 30^ T U in Solveseo-100 from 2 M nitrio

aoid was ssporfced to bs about 1 '« The sstracted uranium dGoreasQa tha

eonoentsation of frao TLk. available for ths eztraotion of neptuniua which

results the deersas? of Hp(lV) distribution oesffloiesit with inoraasiag

uranium oonoantratlon as observed..

4. S. Effect of Diluent

It is knoisn that the diluents hava pronouaosd Qffsot on ths sstssc°

^ '0tion of Qleuaa-bs ' 0 Tha variation of the distribution oosffieieat with tha

diluent was attributed by Ta»fe@v" to the ohange in tfes diluent golaEitye

Ths distribution cosffioiant data for Ip(lV) obtainsd by using different

J diluents for TL& gas eummariaQd in fablo 2 and ar@ comparad @ith similar

litsraturs date for Hp( V) aad Bn(lV)a i t een be soea that diluents have

pt'Onouaced effect on tfea estsaotiea of both neptualwa and plutoniua m

ozpaotod (ulgo 3)0

4.6, StJipping

Sinee thi dlitsibution cosffioient of MpUv) into TM ia fairly

aigfe aTOa fsoa dilute aitslo aeifi oolutioa the stelpplai of nepttrates

b^ gsdueiaa taa aqueous aitric acid concentration is aet

oossplearing agents msss uaed to etudy the feasibility of esisg t-hsas

« a -

reagents to strip neptunium from M>&» Chesne• et el rQcomaenaed a mixture

of 1.5M sulphuric aoid and 0.07M nitrio aoid for stripping the Plutonium into

the aqueous phase fron 3&A phase. SoukeV1' reportQd the possibility of using(32)

formic aoid as a. stripping agent fa? pluteniuB «hereas C©leEaaw ' eat

Hasffner ^ proposed acetio aoid for the same purpose a EsparlEsnts wasa

carried oat using all these stripping agents as wsll ©s perohlorie eoiS and

the results axe sumnasieed in Tables 5 snd 4« It son b@ aaoa fros h@se data

that all the reagents atrip Hp(iv) from i^A almost quantitatiTOljo Th@

affeotiTS stripping of Hp(iv) fey perohlorio @oid may %s dus to ths high

extraotability of cl0." ion Into TIA because of its poor hydration. Aoetio

and formio acids probably bahave as bidentate llgands and form eomplexeg

Hp(lV) nhioh z«£$ be only oetionio and axe not extracted by

R E F E R E N C E S

1* Smith; B»L* and Faga, J.E.e J> Soo= Chem*62.. 4S (1948)*

2. Sheppard, J,C, USAEC B@port HW-51958 (1957)-

3* Wileon, A.S*, Proo. 2nd BH Int. conf* S^AE, j^B 348 (1958)

4* Vanghen, V. and Mason* P.A., OSAEG Report TID-12665 (1%O)

5* Coleman, C.P., Huol. Sol* Shg., IJ., 274 (1963)O

6* Baronoelll, P., at al.f Hucl. Sol* Eag.f VJ., 298 (1963).

7* Chesae1 A.f Koahly, 6. and Bathellier, A«« Hucl* Sci« Eng»9

8* Duboz, M.» Enftrgio Rucleaire, £ , (4)p 226 (1965).

% Champion* J . and Chesne', A., 0EA-R-26O7 (-1964).

10« GouriBae Far D# and Bathellier, A., Badiochim Acts., 15(4) 187 (197O)9

11. Bathellier, A @t el*9 ibid., Jl (4) 191 (1970).

12. Wilson, A.S., HST-68207 (19S1)»

13» Patil, S.K., ©t al - MHC/i=i40 (1971)O

14<> Moor®, F.L., Anal© CSHQIUOO 29_, 1941 (1957)0

1§« Srinirasan, N., ©t al., IAEC-374 (1968).

Vegal, A.I., "fest Book of Qjaantitasfeiv© XnorgBnio3 d Ed. p»535 O96i)o

17o OBML Maater Analyisicel Manual TID-7015, Hathod He» 1=215212

18e OML Maater Analytical Manual TID-7015, Mathod Hoo 9-042200

19» Buohanon, B.F.» et al., Talaata, £, 173 ( 1 % O ) .

20» Bolandi, G.g st al, UP- = 14945 (1964)0

210 Stevenson, CoEo0 and Paige, DeMo, React» Fuel P T O C O O Q ,Tech., 10 (3) e 247 (1967)O

220 Colomans CoF., Atomic Energy Review^ 2_ (2) 3 (1964)0

23o Van Gael, -J.'N.C, Thesis "Recovery of Para Plutooium byExtraction with Trilauiylamine and Direct Prooipitation°pLaboratories fo? Industrial Bavalopmant of Earochamia, Mol«Belgium (January, 1968)o

24« Kumar, Se?«, Kapoor, SoCo, and Jain, S«Po, IABC-476 (197O)«

25» Kedas, WoB9(, st al, Euol. Sole Eog., 1£, 287 (1963)«

Wilson, A.So, Proe» 2nd Int. Conf. (DH) PUAB Ganava,348 (1958).

27o Baronqalli, P e, Sc^bcnajG^ and Ziff@raxo, M., BadioohiQej I,, 75 ( 1 9 6 3 ) O

28o Brown, Koio, et al«, Indo Eng» Chem.f

i?o fsube, M., J. Isorg. Huol. Chem.9 12., 174 (1959)«

30e Chesne', Ao, Kohely, <*«, end Bathellier, A»9 "SolvsntEstraotion Chemiat^" aymposiume G t l i l g fsnn

S ( )

- 10 -

* Stlieafeim* 4©tft9B & (g) 71

32* 0©l«aan#

Int . Conf. Gsaevaj 10, 370 (1fS§

Table - 1

EFFECT OF URANIUM(VI) CONCENTRATION ON THE EXTRACTIONOF Np(IV) BY 20% TLA IN SOLVESSO-100 FROM 2 M NITRIC ACID

50 100 150 200 g§0 3m

eoaffieicmt of «>3 3*5 2.?

Table - 2

EFFECT OF DILUENT ON THE EXTRACTION OF Np(IV) BY TLACONCENTRATION OF TLA - 20% (v/o)

Cono.ef

1

*

4

i

».T?0o0

82 06

t « 34<.T

§73 S4c2

311 ?Oo4

262 92 <>e

© <• Bafe»

f " •

ES .30^300

180

300

400

450

sneo 15

o 21

, 24

• 34

116,3

227.1

25©

650

aes

864

1061

Doi5flqr

go

140

220

450

760

900

1000

Table ° 3

STRIPPING OF Np(IV) FROM TLA PHASE BY SULPHURIC ACIDAND NITRIC ACID MIXTURE

phase « Stslfhusl© &oi& 4- a&tsel©0*01 M S l ^

piiwe » SO^ SM ia §O1V«SBO°

0.5

0.8

1.0

1.5

2.0

1.5

1.2

1.0

0,5

0

1.17

O«36

0.18

0.014

0.003

Table - 4

STRIPPING OF Np(IV) FROM TLA PHASE BY FORMIC,ACETIC AND PERCHLORIC ACIDS

phase ©nd pQEehiori© aei ia

in pith

Ceasoatscaiica of

Ao@tio ooid

0*5

O0OO252

0^00464

0.003S

O..OC030

10

25UJ

u.ILUlooaso

aE!Ga

10

LINE W!Tt-l SLOPE

i L I I I I i i t I i »I

10-i I 10V / 0 TLA IN SOLVESSO-10©

FIGURE-). DISTRIBUTION RATIOS FOR OTRACTION OFFROM 3M HKOg V« COCEKTRAfJON OF TLA INSOLVESSO-600.

S615OEfa©

©

A@ui©ys PHASE c )

s-a.S@LVESS@»8@0 WITH WiTfti© A€SB g©MeE^TRATI0r4.

I-tuu

ui ,A2o2o

mS

!0

oX

•

XYLENESOLVESSO- 100

OOOECANE

. SHELL SOL-T

Np ( IV)

Pu CIV)

0 I g 3 4CONCENTRAT20N OF HNO3(Rf3)

FIGURE- 3. EFFECT OF DILUENT OH THE EXTRACTIONAND Pu(rV) INTO gO%fLAv