extraction of tungsten and rhenium by basic or neutral extractants in xylene from mineral acidic...

J.RADIOANAL.NUCL.CHEM.,LETTERS 106 /i/ 55-64 /1986/

EXTRACTION OF TUNGSTEN AND RHENIUM BY BASIC OR NEUTRAL EXTRACTANTS IN XYLENE FROM MINERAL ACIDIC MEDIA

R. Shabana, S.M. Khalifa M, S. Abdalla, H.F. Aly ~

XNuclear Chemistry Department and Hot Laboratory Centre, Atomic Energy Establishment,

P'O. 13759, Cairo, Egypt

Received 23 July 1986 Accepted 29 July 1986

Extraction of WO~- and Re04 by Adogen-381, tricaprylmethylammonium chloride, Hyamine IO-X, trioctylphosphine oxide or dibenzylsulphoxide in xylene from HN03, HCI or H2SO 4 acid medium was investigated. Based on the separation factors obtained, the separation of ReO~ from WO~- was elucidated. ReO~ was separated from WO~- in high radiochemical purity: >99.9% by three successive extractions and strippings using Adogen,381 from HCI or HNO 3 acid medium.

INTRODUCTION

The extraction of W/VI/ by methyl isobutyl ketone or

tributyl phosphate from mineral acids containing fluoride 1

was studied by De and Rahaman . W/VI/ was extracted quanti-

tatively by oxime 2 in chloroform from acid solutions at

pH 2.5-3.5. Amines extracted tungsten from fluoride 3 and

chloride 4 solutions. Quaternary ammonium salts extracted

W/VI/ from nitric acid 5 and perchlorate 6 solutions. Per-

rhenic acid was extracted from strong acid solutions by

trioctylphosphine oxide 7. Trilaurylamine extracted Re04

55 ElseWer~quo~&A.Laus~ne A k ~ Klad6, B~a~st

SHABANA et al. : EXTRACT ION OF TUNGSTEN AND RHENIUM

quantitatively from different acid media S . As related to

the acid media, the extraction of Re04 by tertiary amines

was found to decrease in the order: H2SO 4 > HCI > HNO 3

/Ref. 9/. In this communication the extraction behaviour

of WO~- and Re04 by Adogen-381, tricaprylmethylammonium

chloride, Hyamine IO'X, trioctylphosphine oxide or di-

benzylsulphoxide'in xylene from HNO 3, HCI or H2SO 4 acid

medium was studied to find and develop a suitable ex-

traction system for the isolation of rhenium from tungsten

to be applied for the 188W § 188Re generator.

EXPERIMENTAL

Chemicals and radiotracers

Adogen-381 was obtained from ADM Chemicals, USA. It

comprises tertiary amines /95.5% min.-mainly tri-isooctyl-

amine/, secondary amines /3% max./, primary amines /1%

max./ and water /0.5% max./. Its average relative molecular

mass is 360. Tricaprylmethylammonium chloride /TCMA/ was

purchased from Fluka, Switzerland as a pure product. Hy-

amine iO-X,/diisobutylcrysoxyethoxyaethyl-dimethyl-ammo-

nium chloride monohydrate; C28H44CINO2.H20/ used was a

pure product obtained from Fluka. Trioctylphosphine

oxide /TOPO/ of AR purity grade was supplied by BDH, Eng-

land. Dibenzylsulphoxide /DBSO/; C6H5CH2SO , was obtained

from Fluka, Switzerland, with a pure label. Xylene

/mixture/ was supplied by Cambrian Chemicals, England,

and used as a diluent. All extractants and the diluent

were used without further purifications. The mineral acids

HNO 3, HCl and H2SO 4 were of AR grade and supplied by BDH,

England. Spectroscopic pure rhenium metal was obtained

from Johnson Matthey, and AR grade /BDH/ sodium tungstate

were utilized as target materials.

56

SHABANA et al. : EXTRACTION OF TUNGSTEN AND RHENIUM

The radioactive tracers used were prepared in situ I0.

Neutron irradiated sodium tungstate was dissolved in bi-

dist~lled water to give a tracer solution containing

185W /T = 75 d/. The irradiated rhenium metal was dis-

solved in IM HNO 3 in the presence of few drops of H202

and diluted with bidistilled water to give a tracer solution

containing 186Re + 188Re /T = 90.6 h and 16.7 h, resp./.

The. concentration of the radioactive tracers used was al-

ways less than Io-5M.

Extraction procedur 9

Preliminary experiments indicated that preequilibrat~on

and equilibration take less than 15 and 40 min, for all

the experiments carried out, alternatively.

The preparation of the samples for y-radiometric as-

say was as that previously reported II. The radioactive

purity of the prepared and separated radiotracers were

estimated using the y-spectrometer 1024 multichannel

analyzer, system Bs 27/N, West Germany.

RESULTS AND DISCUSSION

The extraction of rhenium and tungsten by Adogen-381,

TCMA, Hyamine IO-X, TOPO or DBSO in xylene from HNO 3,

HCI or H2SO 4 acid medium was investigated as a function

of acid concentration; Figs 1-4. Amines such as Adogen-

381, TCMA or Hyamine IO-X extract metals via anion-ex-

change reactions or by adduct formation 12'13. Neutral ex-

tractants such as TOPO or DBSO extract metals by ion as-

sociation or ion-pair formation !4'15 Rhenium and tungsten

are known to be extracted as oxianions by basic or

neutral extractants 13'15

From nitric acid medium, the extraction of ReO4 or

WO by the basic extractants: Adogen-381, TCMA or

57


=, 10 3 0 ~

P = 10 2 0

. - -

a

o ReO~,~ Adogen-381 �9 wo~-J(4 'l.) A Re~l TCMA �9 wo,~-J (5 "/.) D ReO~.~ Hyamine IOXX �9 w~J(o.8 .~.)

10-

i0 -2

10 -3

10 -I I ~ 10

1 0 - 4 ~ I I I ,

10 "~ I 10 10 "~ I I0

Nitr ic ac id concentra t ion, M

Fig. l. Effect of nitric acid concentration on the ex~ traction of ReO~ and WO 2- by Adogen-381, TCMA or Hya/nine IO,X- in xyl4ne

Hyamine lO-X decreased with different rates as the acid

concentration increases; Figs 1,3,4. The distribution

of the oxianions between the two phases - in general -

took the order: Re >> W, Re > W, Re > W for Adogen-381,

TCMA, and Hyamine IO-X, respectively. The continuous

decrease in the extraction of both oxianions by increas-

ing the acid concentrations is related to the compe-

tition for the extraction of nitric acid 16.

From hydrochloric acid medium the extraction of ReO4

with Adogen-381 or TCMA increases as the acid concentration

58


Fig.

Fig.

c. 10 o Re021 (5 /.) o �9 w o,,-~ o ~ s o 0 ,_ A RoO2J(2 "/.1 m 1

D

.~ 10- I

10 -2

10-3

I I I I ~_ l , ~ ,i;..l ~ t ,

10 -I I I0 -I I 10

Nitric acid concentrut ion M 2 . ~ . . f f e c t o f n i t r i c a c i d c o n c e n t r a t i o n on Lhe ex- -

traction of ReO; and WO 2- by TOPO or DBSO In x y l e n e

10 3 o"

,~ 102

'~_

N 10 ?5

o ReO~'[ Adogen-381 I �9 w ~ - J (4 "I.)

�9 R e q l TCI,'~

w o ~ ! c5 ".~ 10 -I o R,o;. l ToPo

,Ib,. w ~ - J (S . i . ) 1o-' ' , i ~ , I , i ' ! , I ,

10 -I 1 I 10 I 10 Hydrochloric acid concentrntion, M

3. Effect of hydrochloric acid concentration on the extraction of Re04 and WO~- by Adogen~381, TCMA or TOPO in xylene-

59


I o R , O ~ Adog~-381 �9 W ~ -J (4 "l.)

, R,o I TCMA �9 wo l (5'.>

io ~ o" --~ ReO;,~ TOPO = : �9 wo~-) (s "I.)

Id-

"r"

II fa I , I , I I - I - - - - - ~ ~ I ,

I0 -~ I I 10 1 10 5ulphurir acid r M

Fig. 4. Effect of sulphuric acid ~oncentration on the extraction of Re04 and WO 4" by Adogen~381, TCMA or TOPO in x@lene -

increased up to certain maxima related to the extractan~

used, followed by different decrease as the acid con-

centration increases. The respective extraction behavio~r

of WO~- exhibits an opposite tendency in relation to Re04;

Fig. 3. The distribution took the sequences: Re >> W for

Adogen-381 and Re > W for TCMA.

The extraction of both oxianions by Adogen-381 or

TCMA from H2SO 4 medium /Fig. 4./ was found to be more ef-

fective /D > 5-150/ and the distribution took the order:

Re > W. The extraction of both radionuclides increases

by increasing H2SO 4 concentration up to a certain value,

related to the extractant used and the element investi-

gated; followed by different decrease at higher acid con-

centrations. The increase in the distribution can be re-

lated to the extraction of Re04 and WO~- when they are

exchanged with the sulphate form of the amine 12. At high-

eracid concentrations, the hydrogen sulphate anions

60


predominate and compete for the amines leading to a de-

crease in the extraction of both Re/VII/ and W/VI/ /Ref.

4/.

With the neutral extractants: TOPO or DBSO /Figs 2-4/

the extraction behaviour of both oxianions from the three

acid media: HNO 3, HCI or H2SO4, was found to be more or

less of the same manner. As the acid concentration was

increased, the distribution increased reaching maxima

related to the extractant employed, the acid medium and

the element extracted. These maxima were followed by

different decrease as the acid concentration increases.

Using HNO 3 the distribution took the sequence: W > Re

for TOPO or DBSO while with HCI and H2SO 4 the respective

order is - in general - Re > W for TOPO indicating

the effect of the acid.

Based on the distribution data of both radiotracers

investigated as related to the acid media /Figs 1-4/ 17

the separation factors /e/ of Re/W were calculated

- in details - for the three acid systems. The values

found indicated that the separation of Re from W using

H2SO 4 with Adogen-381, TCMA or TOPO is impracticable,

since both elements exhibit high distributions /Fig. 4./

which do not facilitate the interseparation of both

elements irrespective of their low e values. Therefore,

the separation via H2SO 4 system was excluded.

Considering the extraction from HCI medium by TCMA

or TOPO, the ~ values of Re/W were found, also, unsuit-

able due to their high distributions /Fig. 3./ which

diminishes the importance of their relatively high

values. However, with ~dogen-381, the separation was

found suitable at 6M HCI; DRe ~ 280, D W = 0.20 and

> 14OO. Practically, three successive extractions for

Re at 6M and strippings at 2M HCl /DRe = 0.O24/, gave

61


66~2% of the original radioactive rhenium in high radio-

chemical purity: >99.9%.

Considering the extraction from HNO 3 medium by TCMA,

Hyamine IO-X, TOPO or DBSO the separation of Re from W

was found impracticable, where the suitable ~ values

were faced with high or low distributions for both

elements, Figs 1.,2. However, with Adogen-381, the

separation was found suitable at IM HNO3; DRe = 8.5,

D W = 0.09 and ~ > 94. Practically three successive ex-

tractions for Re at IM and strippings at 4M HNO 3

/DRe = O..O14/ gave 90~3% of the original radioactive Re

in high radiochemical purity: >99.9%.

REFERENCES

i. A.K. De, M.S. Rahaman, Talanta, ii /1964/ 601.

2. J. Starg, Anal. Chem. Acta, 28 /1963/ 128.

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4. T. Ishimori, Data of Inorganic Solvent Extraction, JAERI/Japan At. Eng. Res. Inst. /1963/ 1047, /1964/ 1062 and /1966/ 1106.

5. P.I. Artyukhin, E.A. Strartseva, Yu.L. Mitaykin, I.M. Ivanov, L.M. Gindin, G.G. Glukhov, Radiokhimya, 14 /1972/ 150.

6. A.M. Wilson, O,K. McFarland, Anal. Chem,, 36 /1964~ 2488.

7. J.J. Bucher, M, Zirin, R.C. Laugen, R.M, Diamond, J. Inorg. Nucl. Chem., 33 /1971/ 3869.

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9. L.G. Arokhina, N.A. Agrinskay~, V.I. Petrashen, Zh. Neor~. Khim., 15 /1970/ 155.

62


i0. S.M. Khalifa, H.F. Aly, J. Inor9. Nucl. Chem., 42 /1979/ 1189.

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12. C.F. Colman, K.B. Brown, J.G. Moore, D.J, Course, Ind. EnH~ Chem., 50 /1958/ 1756.

13. A. Beck, D. Dyrssen, S. Ekberg, ~cta Chem, Scand,~ 18 /1964/ 1695.

14. A.K. De, S.M. Khopkar, R,A, Chalmers, Solvent Ex- traction of Metals, Van Nostrand Reinhold Comp,~ London, 1970.

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extraction of tungsten and rhenium by basic or neutral extractants in xylene from mineral acidic...

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