thorium recovery

8/13/2019 Thorium Recovery

1/45

--F-

ORNL-2173

PROGRESS REPORT ON S E P W T I O N ANlDA E LIQUORS BY THE

AMEX PROCESSv 3. cmme

8.b.

CENTRAL RESEARCH LIBRARYDOCUMENT COLLECTION-

L L I A R Y LOAN COPYDO NOT TRANSFER TO ANOTHER PERSON

If you wish someone else t o see th is document,send in name wit h document and the libr ary willarrange a loan.

GE NATIONAL LABORATORYOlPQRAT'EDB Y

UNCOM CARBIDE NUCLEAR COMPANYemA Division of Urnion Carbide a n d Ca r b m Corpolratien

-ST OFFICE BOX X OAK RIDGE, T E N N E S S E E


2/45


3/45

UNCLASSIFIED ORNL- 2173Chem st ry

Cont r act No. , W 7405- eng- 26

CHEM CAL TECHNOLOGY DI VI SI ONChemcal Devel opment Sect i on C

PROGRESS REPORT ON SEPARATI ON AND RECOVERYOF URANI UM AND THORI UM FROM

SULFATE LI QUORS BY THE AMEX PROCESS

D, J . Cr ouseK. B . BrownW Do Ar nol d

Date I ssuedDEC 2 6 1956

OAK RI DGE NATI ONAL LABORATORYOperat ed byUNI ON CARBI DE NUCLEAR. COMPANYA Di vi si on of Uni on Carbi de and Carbon Corporat i onOak Ri dge, Tennessee i

UNCLASSIFIED


4/45


5/45

UNCLASSI FI ED - i i i -

1.2.3.756.

7-26.2728.293031323334-35 9363738394041.424344.4546.4748.

I NTEREaAL DI STRI BUTI ONORNL-2173Chemst r y

C E. Cent erBi ol ogy Li br ar yHeal t h Physi cs Li brar yCent r al Resear ch Li brar yReact or Experi ment alEngi neer i ng Li br ar yLaboratory Records Depart mentLabor atory Records, ORNL R.C.A M Wei nbergL, B Emet (I(-25)J e P. Murray (Y-12)J . A Swart out 'E, H Tayl orE. D, Shi pl eyF. L. Cul l erM L. Nel sonW H J or danC. P, Kei mJ . H. Frye, Jr .S, C. Li ndA. H Snel lA . Hol l aenderM T. Kel l eyI(. 2. Mor ganT. A . Li ncol nR S. Li vi ngst onA . S. Househol derc s. Harr i l l

49. C E. Wnters50. D W. Cardwel l51. E. M Ki ng52. W, Ke Ei ster53. F. R, Br uce54, D, E. Ferguson55. R. B, Li ndauer56, H, E. Goel l er57. D, D Cowen58. R A , Charpi e59. J . A. Lane60. M J. Ski nner61, RY E. Bl anco62. G E. Boyd63. We E Unger64. R. R. Di cki son65. A , T. Gresky66. E D Arnol d67. C, E. Gut hr i e68. J. W Ullmann69, K. B. Brown70. K. 0 ohnsson71. H, M, McLeod72. W. De Ar nol d73. M Benedi ct ( consul t ant )74. D L, Kat z ( consul t ant )75. C. E, Lar son ( consul t ant )76. G T. Seaborg ( consul t ant )77. ORNL - Y- 1 2 Techni cal Li br aDocument Ref erence Sect i on

EXTERNAL DI STRI BUTI ON78. R. F. Bacher , Cal i f or ni a I nst i t ut e of Technol ogy79. L. Squi r es, duPont Company, W l mngt on80. Di vi si on of Research and Devel opment , AEC, OR081-665. Gi ven di st r i but i on as shown i n TID-4500 ( 12t h ea. ) under Chemst r y cate

(200 copi es - OTS)DI STRI BUTI ON PAGE TQBE REMOVED I F REPORT I S G I V E 3 PUBLI C DI STRI BUTI OR

UNCLASSI FI ED


6/45


7/45

i/.. . .. .. -v.-

CONTENTSPage

0. 0 ABSTRACT. . ........................................ 12. 0 ' SUMMARY .......................................... 3

3. 1 Ext r act i on of Ur ani um and Thor i um . O O O . O 53. 1. 1 Separat i on of Urani um f romThor i umby Sel ect i ve Ur ani um Ext r act i on. a . e . 0 o 5

Synt het i c Sul f at e Li quor s. ............ 83. 1. 2 Ext r act i on of Thor i um f r om3- 1. 3 Separ at i on of Thor i um f r omUr ani umby Sel ect i ve Thor i umExt r act i on. . . 8

3. 2 Thor i um Str i ppi ng. . . . ........................ 16Chl or i de Sal t Sol uti ons. . . . . . ......... 163. 2. 1 St r i ppi ng, wi t h Ni t r at e or

3. 2. 2 St r i ppi ng w t h Sod' i umCar bonat e Sol ut i ons. . . . . . . . . . . . . . . . . . . 194. 0 CONTI NUOUS COUNTERCURRENT TESTS. . . ................ 19

4. 1 Ur ani um Recover y Cyc l eo ODO. . OOOOOO. .. . . . . . . . 214. 2 Thor i umRecover y Cycl e. O . O o e O . O O . . O O o O . O O O . . 26

5. 0 ESTI MATED REAGENT COSTS. .......................... 305, l Urani um Recovery Cycl e....................... 305, 2 Thor i umRecover y Cycl e, ...................... 30

APPENDI XESA, Desi gn and Oper at i on of t he 3.4agnesi um Oxi de St r i ppi ng Syst em . . . . . . . . . . . . . .Bo Descr i pt i on of Reagent s, . e . . e o . 36


8/45


9/45

- 1 -

0 . 0 ABSTRACT

T he a m in e e x t r a c t i o n (Amex) p r o c e s sc a n be u s e d e f f e c t i v e l y f o r t h e e x t r a c t i o na n d s e p a r a t i o n o f u r a ni um a n d t h o r iu m f r o ms u l f a t e l i q u o r s i n w hich t h e s e meta l s co-ex i s t , , W it h p r o p er c h o i c e o f r e a g e n t s ,e i t h e r u ra ni um o r t h or i um c a n b e e x t r a c t e df i r s t an d t h e o t h e r e x t r a c t e d i n a s e c o n dc y c l e . R e a g e n t c o s t s a r e e s t i m a t e d t o bel o w f o r b o t h t h e u ra n iu m a n d th o r i um r e c o v e r yc y c l e s

1 0 IN T R O D U C T IO N

E x t e n s i v e s t u d i e s o n t h e re c o v e r y o f u ra ni um a nd o t h e rme t a l s f rom a c i d l i q u o r s by e x t r a c t i o n w i t h l o n g c h a i n a mi ne si n h y d ro c a r o n d i l u e n t s (Amex p r o c e s s ) h av e b ee n r e p o r t e dpreviously. 1-6)o n t h e Amex p r o c e s s w i t h r e g a r d t o i t s a p p l i c a t i o n f o r t h es e p a r a t i o n a nd r e c o v e r y o f u ra ni um a nd t h or i um f r om s u l f u r i ca c i d o r e l e a c h l i q u o r s i n wh ich t h e s e t w o e l em e n ts c o e x i s t .

The p r e s e n t r e p o r t d e s c r i b e s f u r t h e r s t u d i e s

S i n c e t h e known o c c u r r e n c e s o f t h or i um i n a p p r e c i a b l ec o n c e n t r a t i o n i n d o m e s ti c ur an iu m o r e s a r e r e l a t i v e l y r a r e ,t h e p r o c e s s e s u s e d o r b e i n g d ev e lo p ed f o r domest ic a p p l i c a -t i o n ha ve n o t b e en f a c e d a s y e t w i t h t h e pr ob le m o f s e p a r a t -i n g a nd r e c o v e r i n g b o t h meta l s . T h i s pr ob le m , o n t h e o t h e rh a n d , i s o f c o n s i d e r a b l e i m po rt an ce i n t h e p r o c e s s i n g o fc e r t a i n C a na di an ore s . Large b o d i e s o f u r a ni u m- t h or i u m o r e s ,r e c e n t l y d i s c o v e re d i n t h e B l i n d R iv e r d i s t r i c t , a r e nowb e i n g : t r e a t e d by a p r o c es s which i n c l u d e s s u l f u r i c a c i dl e a c h i n g , c o u n t e r c u r r e n t d e c a n ta t i o n an d f i l t r a t i o n t o o b t a i na c l e a r l e a c h l i q u o r , a nd s r t i o n o f u ra ni um o n a n i o ne xc ha ng e r e s i n s i n c ol um ns r P The s u l f u r i c a c i d l e a c h i n gs t e p d i s s o l v e s a l mo s t a l l t h e ur an iu m a nd a n a p p r e c i a b l ea mo un t o f t h o r i u m f r o m t h e ore., The a n i o n e x ch an ge s t e p i se f f e c t i v e f o r a c h i e v i n g c o mp le te u ra ni um r e c o v e r y f ro m t h el e a c h l i q u o r s , b u t i t i s n o t e f f i c i e n t i n s e p a r a t i n g t h eu r an i um fr o m t h e t h o r i u m , T he t h o r i u m c o n t e n t o f t h e u r an i umc o n c e n t r a t e i s s u f f i c i e n t l y h ig h t o c a u s e s e r i o u s pr ob le ms i ne x i s t i n g r e f i n i n g p l a n t s w here t h e s e p r od u c t s a r e f u r t h e rp r o c e s s e d i n t o p u r e u ra n iu m c o mp ou nd s a n d metals . ( 8, A l s o ,p r o v i s i o n f o r r e c o v e r i n g t h or iu m a s a v a l u a b l e , o r p o t e n t i a l l yv a l u a b l e , b y- pr od uc t f ro m t h e B l i n d R i v e r o r e s h a s n o t b e e nmade

I n t h e c o u r s e of p r e v i o u s s t u d i e s o n t h e Amex p r o C e s s ,t h e e x t r a c t i o n s of numerous meta l s , i n c l u d i n g t h o r i u m fr om


10/45

- 2 -

sul f at e sol ut i ons were i nvest i gat ed. I t was f ound t hat cer -t ai n amnes whi ch possessed hi gh ur ani um ext r act i on powerhad negl i gi bl e ext r act i on power f or t hor i um Al so, i t wasf ound that cer t ai n ot her am nes wer e ef f ect i ve extr act ant s ,f or t hor i um ' the ext r act i on coef f i ci ent s bei ng hi gher , i nsome cases much hi gher , t han t hose f or urani um The var i at i oni n ext r act i on per f or mance of t he di f f er ent am nes coul d becor r el at ed w t h var i at i ons i n t he compound t ype and st r uct ur e.On the basi s of t hese observat i ons a prom si ng pr ocess wasdevel oped f or t he r ecovery of t hor i um and ur ani um f romsul f ur i c aci d di gest s of monazi t e sand. 3 )st udi es wer e al so made on l i quor s of t he composi t i on t hatm ght be der i ved f r omBl i nd Ri ver t ype ores, and ef f ect i vethorium-uraniumLseparations were demonst rated. ( 2)Pr el i m nar y

The i nt ent of t he present st udi es has been to eval uat emore cl osel y t he f easi bi l i t y and econom cs f or appl yi ng t heam ne ext r act ant s t o the r ecover y and separ at i on of ur ani umand t hor i um f r om l i quor s of t he Bl i nd Ri ver t ype. Twogener al process possi bi l i t i es have been consi der ed: ( 1) t heext r act i on of ur ani um i n a f i r st cycl e w t h subsequent ex-t r act i on of t hor i um and (2 ) ext r act i on of t hori um i n t he pri -mar y- cycl e w t h subsequent ext r act i on of ur ani um Ther esul t s f r om t hi s wor k may al so be used i n eval uat i ng acombi nat i on of sol vent ext r act i on w t h present i on exchangepract i ce wher ei n t hor i um i s r ecover ed f r om t he l i quor pr i ort o or af t er t he ur ani um separ at i on st ep,

Sever al am nes whi ch wer e expect ed f r om ear l i er wor k t opossess f avor abl e pr oper t i es f or t he i nt ended appl i cat i onwer e sel ect ed f or st udy al ong wi t h, f or pur poses of compar i -son, sever al compounds whi ch wer e expect ed t o gi ve rel at i vel ypoor perf ormance. Numerous bat ch ext r act i on t est s . were madet o compar e t he ext r act i on abi l i t i es of t he di f f er ent r eagent sand to eval uat e t he i mport ance of sever al pr ocess var i abl es.Si nce sampl es of ur ani um t hor i umores or pl ant l i quor s wer enot avai l abl e, al l t est s wer e made on synt het i c l each sol u-t i ons, Pr el i m nar y eval uat i ons of t hr ee di f f er ent met hodsf or st r i ppi ng t hor i um f r om t he or gani c ext r act s wer e al somade by batch t est i ng. Ur ani um st r i ppi ng was not exam nedsi nce sever al f f ect i ve methods have been devel oped i nprevi ous ~or k . 7~9~96)smal l m xer - set t l er equi pment t o demonst r ate a two cycl eAmex process f or t hor i um and ur ani um r ecover y under condi t i onsof cont i nuous count er cur r ent oper at i on. Reagent consumpt i onsf or bot h the ur ani um and thor i um cycl es were est i mat ed f r omt he dat a obt ai ned,

Fi nal l y, a bench- scal e r un was made i n

Di scussi ons of sever al t opi cs of gener al per t i nence t ot he use of amnes as ext r act i on agent s have not been wi t hi nt he scope of t hi s r epor t , e. go, avai l abi l i t y of di f f er entr eagent t ypes, r eagent st abi l i t y, di l uent compat i bi l i t i es,ext r act i on sel ect i vi t i es w t h r egar d to ot her met al s, probabl er eact i ons t aki ng pl ace dur i ng ext r act i on and st r i ppi ng, phase


11/45

- 3 -

s e p a r a t i o n , e t c , T he se t o p i c s h ave b ee n t r e a t e d i n c o n s i d e r -a b l e d e t a i l i n p r e v i o u s r e p o r t s e ( 1 , 2 r 4 9 6 )t h a t t h e s e r e p o r t s b e r ev ie w ed a s b a c k g ro u n d mat e r i a l f o r t h ep r e s e n t d i s c u s s i o n sI t is s u g g e s t e d

2 , O SUMMARY

P r e l i m i n a r y b e n c h - s c a l e s t u d i e s h av e b e en co m pl e te d ont h e u s e o f t h e amine e x t r a c t i o n (Amex) p r o c e s s f o r t h er e c o v e r y a nd s e p a r a t i o n o f u ra ni um a n d t ho r iu m f ro m s u l f u r i ca c i d o r e l e a c h l i q u o r s i n wh ic h t h e s e t w o e l e m e n t s c o e x i s t .I n b a t c h e x t r a c t i o n t e s t s o n a l i q u o r o f t y p i c a l th or iu mo r u ra ni um c o n t e n t , e x c e l l e n t s e p a r a t i o n of u ra ni um f ro mt h o r i u m w a s , ac h ie v ed by s e l e c t i v e l y e x t r a c t i n g t h e ur an iu mw i t h a t e r t i a r y amine s u ch a s t r i ( i s o - o c t y 1 ) - o r t r i - n - o c t y l -a m in e, I f s c r u b b i n g s t a g e s were p r o v i d e d , o r i f t h e C rg a n icp h a s e w a s l o a d e d t o n e a r s a t u r a t i o n w i t h u r an i um , goods e p a r a t i o n s c o u l d a l s o b e o b t a i n e d w i t h s e c o nd a r y a m in es i nw hic h t h e a l k y l c h a i n s w e r e b ra nc he d i n c l o s e p r o x i m i t y t o t h en i t r o g e n . Of t h e s e c on d a r y a m in e s t e s t e d , Amine S - 2 4 w a ss u p e r i o r i n p e r f or m an ce .Thorium w a s e f f i c i e n t l y r e c ov e r e d f ro m u ra ni um -b ar re nl i q u o r s by e x t r a c t i n g w i t h a b r a n c h e d c h a i n p r i m a r y a m in e o ra s e c o n d a r y a mi ne w i t h b r a n c h i n g a t a d i s t a n c e f rom t h en i t r o g e n , F o r e x a m p le , P ri m en e JM-T ( p r i m a r y) an d d i ( t r i d e c y 1 P )a m i n e ( s e c o n d a r y ) w e r e e f f e c t i v e e x t r a c t a n t s i n t h i s r e s p e c t ,w i t h t h e l a t t e r r e a g e n t p r e f e r r e d b ec a u se o f lower l o s s e s t o t h ea qu eo us l i q u o r s a nd g r e a t e r s e l e c t i v i t y w i t h r e g a r d t o o t h e rmetals s u c h a s i r o n ( I I I ) , E x t r a c t i o n s o f t ho ri um w i t h t h e s er e a g e n t s would be e q u a l l y p o s s i b l e f ro m l i q u o r s t h a t ha d be enp r o c e s s e d p r e v i o u s l y f o r u ra ni um r e c o v e r y e i t h e r by Amex o ra n i o n e x ch a ng e . C om p le te t h o ri u m e x t r a c t i o n i s o t h e r m s wered e t e r m i n e d f o r t y p i c a l l i q u o r s w i th 0 . 1 M d i ( t r i d e c y 1 P )a mi nei n k e ro s en e a s t h e e x t r a c t i n g s o l v e n t . Kt t h i s r e a g e n t c on ce n-t r a c t i o n , t h e i n d i c a t e d maximum l o a d i n g o f t h e s o l v e n t w a sa p p r o x i m a t e l y 3 g T h p e r l i t e r .The p o s s i b i l i t y of f i r s t s e p a r a t i n g t ho r iu m from t h eo r i g i n a l l e a c h l i q u o r , l e a v i n g u r an iu m f o r s u bs e qu e nt r e c o v e r y ,

w a s i n v e s t i g a t e d w i t h t w o a m i n e s w h ic h h a d d e m o n s t r a t e dg r e a t e r t h a n a v e r a g e t h o r i um e x t r a c t i o n p ow er , i . e . P r ime n eJM-T a n d d i ( t r i d e c y 1 P ) am i ne . F a v o r a b l e s e p a r a t i o n s were n o to b t a i n e d w i t h t h e l a t t e r r e a g e n t , t h e r a t i o o f t h o r i u m t ou ra n iu m e x t r a c t i o n c o e f f i c i e n t s b e in g t o o l o w f o r t h e d e s i r e dp u r p o s e , H ow ev er , w i t h P r im e n e JM-TP r e a s o n a b l y e f f e c t i v es e p a r a t i o n a n d r e c o v e r y o f t h o r i u m were shown t o b e p o s s i b l e .T hu s, a n a l y s i s of b a t c h t e s t d a t a i n terms o f a c o n t i n u o u sc o u n t e r c u r r e n t p r o c e s s i n d i c a t e d t h a t e s s e n t i a l l y c o mp le te


12/45

- 4 -

t h o r iu m r e c o v e r y a n d - a d e q ua t e s e p a r a t i o n f ro m ur an iu m c o u l db e a c c om p l i s h ed b y o p e r a t i n g u n d e r c o n d i t i o n s w hi ch wou ldl o a d t h e o r g a n i c p ha se t o n e a r s a t u r a t i o n w i t h t h or iu m.S i m i l a r e nd r e s u l t s s h o u ld b e a t t a i n a b l e when o p e r a t i n g a tlower l o a d in g s by s c r u bb i ng t h e s o l v e n t w i t h d i l u t e s u l f u r i ca c i d ,

T ho rium c a n b e s t r i p p e d f ro m t h e o r g a n i c e x t r a c t bymethods s i m i l a r t o t h o s e d e v e l o p e d e a r l i e r f o r u r a n i u m p r o -c e s s i n g . ( 4 ) F o r e x am p l e, 1 .0 M s o l u t i o n s of n i t r a t e o rc h l o r i d e s a l t s c o n t a i n i n g 0.05-M s u l f u r i c a c i d h av e g i v ene f f i c i e n t r em ova l of t h o r iu m , p Fo vi di ng p r eg n an t s t r i pl i q u o r s c o n t a i n i n g 20-30 g of t h o r i u m p e r l i t e r . Sodiumc a r b o n a t e h a s a l s o shown promise a s a s t r i p p i n g r e a g e n t ,U s i ng d a t a f ro m t h e b a t c h e x p e r i m e n t s a s a g u i d e , a con-t i n u o u s c o u n t e r c u r r e n t t e s t o f t h e Amex p r o c e s s f o r s e p a r a t i o na n d r e c o v e r y o f u r a n i um a n d t h o r i u m was made i n b e n c h - s c a l em i x e r - s e t t l e r e qu ip m en t . T he c o m po s it i on o f t h e s y n t h e t i c

l e a c h l i q u o r u se d i n t h i s t e s t w a s , i n grams p e r l i t e r , 1 , 2 U,0 .2 T h , 1 .0 F e ( I I I ) , 1 . 0 F e ( I I ) , 40 S O 4 ; pH 0.9 . Recovery ofg r e a t e r t h a n 9 9 . 9 of t h e u r an iu m a n d g r e a t e r t h a n 99 of t h et h o r i u m was a c hi e ve d i n a t wo -c yc le o p e r a t i o n . I n t h e f i r s tc y c l e , u r a n i u m w a s r e co v er e d by e x t r a c t i n g i n 3 m i x e r - s e t t l e rs t a g e s w i t h 0 . 1 M t r i - n - o c t y l a m i n e i n k e r o se n e p l u s 3 vt r i d e c y l a l c o h o l , T he -u ran ium w a s s t r i p p e d from t h e e x t r a c tw i t h a n a qu eo us s l u r r y o f magnesium o x i d e , y i e l d i n g a p r o d u c tc o n t a i n i n g o n l y 0 . 0 3 - 0.05 Thoz I n t h e s e co n d c y c l e ,t h o r i u m w a s e x t r a c t e d f rom t h e r a f f i n a t e of t h e u r an iu mr ec o v er y o p e r a t i o n i n 3 mi x er - s e t t l e r s t a g e s w i t h 0.05 Ms o l u t i o n o f d i ( t r i d e c y 1 P )a mi ne i n k e r o se n e , The t h or i um w a ss t r i p p e d f rom t h e e x t r a c t w i t h 1 . 0 M N a C l - 0 . 0 5 M H 2 S 0 4s o l u t i o n an d p r e c i p i t a t e d w i t h ammozia, The p r o d k tp r e c i p i t a t e t h u s o b t a i n e d c on t a in e d o n l y smal l a m o u n t s ofo t h e r metal i m p u r i t i e s . B ase d o n t h e d a t a f ro m t h e c o n t i n u o u sc o u n t e r c u r r e n t t e s t , i t w a s e s t i ma t e d t h a t t o t a l r e a g e n t c o s t smi g h t b e a s l o w a s & 7 6 / l b U,08 f o r u r an iu m r e c o v e r y a n d- 13 &/ 1b T ho z f o r t h o r i u m r e c o v e r y .

C o n t i n u o u s t e s t s h a ve n o t b e e n made o n r e c o v e r y o ft h or i um a n d ura ni um i n r e v e r s e o r d e r t o t h a t d e s c r i b e d ab ov e ,e . g . , r e c o ve r y o f t h or i um by e x t r a c t i n g w i t h a r e a g e n t s u c ha s Pr imene JM-T a n d s u b s e q u e n t r e c o v e r y o f u r an i um by o n e o fs e v e r a l s u i t a b l e am ine r e a g e n t s , ( 4 9 6 ) S i n c e e x c e l l e n t s e pa -r a t i o n s a r e s o e a s i l y o b t a in e d by e x t r a c t i n g u ra ni um w i t h at e r t i a r y amine i n t h e f i r s t c y c l e , i t i s b e l i e v e d t h a t t h i sr e v e r s e s e q u e n c e wou ld b e a l e s s f a v o r a b l e p r o c e s s a r r a n g e-m e nt . On t h e o t h e r h a n d , m i l l s u s i n g a n i o n e xc ha ng e r e s i n sf o r ur an iu m r e c o v e r y f ro m u r an i um - t ho r iu m l i q u o r s a r e a l r e a d yi n e x i s t e n c e . I n s t a l l a t i o n o f a p r i m a r y t h o r i u m r e c o v e r yc y c l e i n t h e s e m i l l s s h o u l d be p r o f i t a b l e s i n c e i t woulde l i m i n a t e t h e p ro bl em of t h or i um c on t a m i na t i o n i n p r e s e n t i o ne x ch a ng e ur a ni u m c o n c e n t r a t e s a n d p r o d u c e , a t t h e same t i m e ,


13/45


14/45

TABLE 1. URANI UM- TEORI UM EXTRACTI ON WTH AM NESFROM 0, 5 M SULFATE SOLUTI ON

~~

Aqueous: 1 g U and 0. 5 g Th per l i t er ; 0. 5 M S O 4 ; pH 0 . 9r gani c: 0. 1 M amneCont act t i me: 2 mnTemperat ure: Room-

Or eani c*R&H 9D- 178 Am ne i n ker osene+ 2 v capr yl al coholAm ne S- 24 i n kerosene

Tr i - n- octyl am ne i n ker osene+ 2-v capr yl al cohol

Tri ( i so- octy1) amne i nkerosene + 3 v tr i decylal cohol

PhaseRat i o( a m

36

36

36

36

Fi nal Concent r aAqucU

DUSTh-~

0. 0470. 29

0. 0240. 26

0, 0110.13

0.0190. 18

*Am ne st r uct ur es are gi ven i n Appendi x B.**Th/ U i n head l i quorTh/ U i n organi c

0. 410. 46

0. 410. 50

0. 470. 40***

0. 490. 51

i on, g,OrgaiU

2. 83 7**>3. 04. 5

2. 84. 5

2. 84. 8

. i ter.cTh0. 250.072

0. 26h

:o. 02.o. 02

0. 020. 02

Ext r act i onCoef ci enlI

U6013

12517

25035

15027

0. 60. 16

0. 630. 04

to. 05(0. 05

70

>110

>70,110

***Poor mat er i al bal ances. Thi s does not have an i mpor t ant ef f ect on t he si gni f i cance oft he dat a, however s si nce bot h phases were anal yzed f or ur ani um and t hori um _

I


15/45

be expected at st i l l hi gher ur ani um l oadi ngs. * Fur t herdecont am nat i on m ght al so be obt ai ned by scr ubbi ng t heor gani c ext r act w t h di l ut e sul f ur i c aci d. I n pr ocesspr act i ce, t he scr ub sol ut i on t hus produced woul d be recycl edto some sui t abl e poi nt i n t he pr ocess st r eamThe di f f er ences obser ved i n t he ef f ect i veness of ur ani um

and t hor i umsepar at i on w t h the di f f erent am nes ar e i nagr eement w t h those ant i ci pat ed f r om ear l i er st udi es on t hesel ect i vi t y of am nes f or ur ani um over ot her met al s as af unct i on of am ne t ype and st r uct ur e. As st ated i n ORNL-19590 "t he ef f i ci ency w t h whi ch ur ani um can be separ ated byam ne extr act ant s f r om t he var i ous met al cont am nant s i sdependent on a number of f act or s. The t ype and st r uct ur e oft he extract ant i s of pr i mary i mport ance, t he pr i mary am nesbei ng gener al l y t he l east sel ect i ve and the symmet r i calt er t i ar y am nes** gener al l y t he most sel ect i ve of t he r eagent st est ed. W t h secondar y am nes, branchi ng of t he al kyl chai nson t he car bon adj acent t o the ni t r ogen i mpr oves the sel ec-t i vi t y over t hat of am nes w t h no br anchi ng or w t h br anchi ngf art her r emoved f r om t he ni t r ogen. Thus, compounds such asC&C 16F27 ( now Am ne S- 24) and R&H 9D- 178 am ne, ar e super , i ori n sel ect i vi t y to compounds such as di l aur yl , di ( 2- but yl oct yl )and di ( t r i decy1 P) am nes. Al so, i t has appear ed t hat C16F27 ( Am ne S- 24) , i n whi ch b h chai ns are br anchedf i r st carbon, has somewhat bet T sel ect i vi t y pr oper t iR&H 9D- 178, i n whi ch onl y one chai n i s br anched at t he f i r stcar bon.

Pr i mary am nes and secondary am nes w t h no br anchi ng orbr anchi ng di st ant f r om t he ni t r ogen wer e not i ncl uded i n t het est s shown i n Tabl e 1, As , suggest ed above, t he pr ef er ent i alext r act i on of urani umw t h t hese compounds woul d have beenpoor , As a mat t er of f act , as descr i bed bel ow and as al so* I t shoul d be not ed, however p t hat at a phase r at i o of 6a/ 10urani um l oadi ng of t he or gani c phase was not f ar f r om t hemaxi mum l oadi ng achi evabl e w t h t hi s l i quor . Al so i t shoul dbe not ed t hat , i n a count er cur r ent ext r act i on syst em l oadi ngi s i ncr eased at t he expense of i ncr easi ng t he number of ex-t r act i on st ages r equi r ed f or compl et e ur ani um r ecovery. I naddi t i on, and possi bl y mor e i mpor t ant , oper at i on of t he systemi n such a manner as t o accompl i sh essent i al l y maxi mum ur ani uml oadi ng of t he br gani c phase r equi r es extr emel y car ef ul con-t rol . The or gani c and aqueous f eed r ates must be accur atel ymeasured and the ur ani um cont ent of t he f eed l i quor and t heamne concent r at i on accur atel y known. I n vi ew of t hese con-si der at i ons the mor e sel ect i ve t er t i ar y am nes descr i bedabove woul d be oper at i onal l y super i or f or t hi s appl i cat i on.

**Unsymmet r i cal t er t i ar y am nes w t h t hree al kyl chai ns ofr easonabl e l engt h shoul d behave si m l ar l y. For mor e compl et edi scussi ons of ef f ect s of r eagent st r uct ur e see ORNL- 1734,- 1922 - 1959, and - 2099.


16/45


17/45

b

TABLE 2 . EXTRACTION O F THORIUM FROM A SYNTHETICLEACH LIQUOR WITH AMINES

Aqueous : 0 .20 g T h , 1.1 g F e ( I I ) , a nd 0 .9 g F e ( I I 1 ) p e r ' b i t e r ;O r g a n i c : 0 . 1 M amTne i n k e ro se n eP h a s e r a t i o : F 1

A s 0.4 M SO, 9 pH 0.9; B , 0 . 6 - SO19 pH 0 . 5C o n t a c t t i m e : 5 minT e m p e r a t u r e : R o o m

Amine*R&H 9D-178Armeen 212**D i ( t r i d e c y 1 P )Primene JM-T

R&H 9D-178Armeen 212**D i ( t r i d e c y l P)Primene JM-T

AqueousAAAA

BBBB

F i n a lPH1 . 01 . 01 . 01 . 0

0.600.600 . 6 00 . 6 0

T h , g / l i t e rAqueous0.0270 .0040.003

(0 .003

0.0970 .014

-c0.0034 0 . 0 0 3

O r g a n i c0 .340 . 4 00.420 . 3 9

0 .190 .360 .400 .39

* A m i n e s t r u c t u r e s a r e g i v e n i n A p pe n di x Bo

F e i nO r g a n i c ,g / l i t e r0 . 1 10.030 .350 . 9 1

0.0260 , 0 1 60.0470 . 8 1

Thor iumE x t r a c t i o nC o e f f i c i e n t( E a

1 31 0 01 4 0

> 1 3 02

26> 1 3 0> 1 3 0

* * D i l u e n t w a s k e r o s e n e m o d i f i e d w i t h 5 v ' t r i d e c y l a l c o h o l .


18/45

- 10 -of i r on i n t he ext ract woul d be expect ed t o be consi der abl yl ower *

Thi s expect at i on i s borne out by t he i sother ms f orext r act i on of t hor i um at pH 0 . 5 and 0 . 9 by 0. 106 M di ( t r i -decyl P)amne ( Fi g. 1). Dat a f r omwhi ch t he i sot l i erms wer epl ot t ed, i ncl ud- i ng anal yses f or t he amount of i r on ext r act edi nt o t he or gani c phase, are pr esent ed i n Tabl es 3 and 4 Atbot h pH l evel s very hi gh t hor i um ext r act i on coef f i ci ent swer e obser ved w t h t hi s r eagent even at r el at i vel y hi ght hor i um l oadi ngs i n t he or gani c phase. The i sot her ms i ndi -cat e a maxi mum t hor i um l oadi ng f r om t hese sol ut i ons of about3 g per l i t er , cor r espondi ng t o about 8 mol es of amne permol e of t hor i um Sl i ght l y hi gher thor i um l oadi ngs wer ei ndi cat ed at pH 0 . 5 t han at pH 0 . 9 , but i t seems possi bl et hat t he smal l di f f er ence coul d be at t r i but ed t o anal yt i caluncer t ai nt i es. As not ed pr evi ousl y, t he amount of i r onextr act ed w t h t hi s am ne was l ow at pH 0. 5, At pH 0 . 9 0al t hough i r o n ext r act i on was appr eci abl e at l ow t hor i uml oadi ngs ( Tabl e 4) onl y rel at i vel y smal l amount s of i r onwere present i n t he organi c phase when i t was l oaded t o nearsat ur at i on w t h thor i um

3. 1. 3 Separ at i on of Thor i um f romUr ani um by Sel ect i veThor i umExt r act i on. The possi bi l i t y of sel ecti vel y ext r act -i ng t hor i um f r oma synt het i c sul f at e l i quor cont ai ni ng 1. 2 gU and 0. 2 g Th per l i t er was st udi ed wi t h ker osene sol ut i onsof Pr i mene J M- T and di ( t r i decy1 P) amne. Both t hese amneshave previ ousl y been shown t o be good ext r actant s f orurani um l s2 4 ) Thus, achi evement of an ef f ect i ve separ a-t i on of t hor i um f r omur ani um out of a l i quor i n whi ch t heur ani um concent r at i on i s appr eci abl y hi gher t han t hat of t het hor i um r equi r es that t he thor i um ext r act i on power of t her eagent be ext r emel y hi gh, i . e. , consi der abl y hi gher t han f orur ani um I f t hi s condi t i on i s met , i t shoul d be possi bl e tokeep t he ur ani um ext r act i on at a l ow l evel by l oadi ng t hesol vent t o near sat ur at i on w t h t hor i um To det er m ne thedegr ee to whi ch separat i ons woul d be af f ect ed by t hor i uml oadi ng i n t hese par t i cul ar sol vent s, t he ext r act i on testswer e car r i ed out at sever al di f f er ent phase r at i os.

W t h di ( t r i decy1 P) amne t he ur ani um and t hor i umseparat i ons obt ai ned were qui t e poor even under t he mostf avor abl e exper i ment al condi t i ons, t he r at i o of t hor i um t our ani um coef f i ci ent s evi dent l y bei ng too l ow f or t hedesi r ed pur pose ( Tabl e 5). W t h Pr dmene J M- T, however ,ef f ect i ve separ at i ons and r ecover i es wer e shown t o be possi bl e( Tabl e 5 and Fi g. 2). For exampl eo i n a si ngl e st age cont act ,90 of t he t hor i um coul d be ext r act ed whi l e removi ng at t he

?

*I r on ext r act i on can al so be r event ed by reduci ng t o t he non-ext r actabl e f er r ous st at e ( 1r


19/45


20/45


21/45

- 13 -

0.400.801 . 2

1. 62. 1 .2.42 .82. 93. 1

TABLE 4. DATA ON EXTRACTI ON OF THORI UM FROM

0. 360.280.22

0. 200.170. 130. 0920. 0300. 019

A SYNTHETI C LEACH LI QUOR AT PH 0. 9 BY DI ( TRI DECYL PI AMI NEAqueous: 0 .20 g Th, 1. 1 g Fe( I 1) 0. 9 g Fe( I I 1) perOr gani c: 0. 106 M di ( t Fi decy1 P) amne i n ker oseneProcedur e: Organi c cascaded agai nst f r esh vol umes ofl i quor and phases sampl ed af t er each con-t act ; phase r at i o was 2a/ 10 on al l con-t act s except the l ast whi ch was 5a/ 10

l i t er ; 0. 4 E SO ; pH 0. 9-

Cont act t i me: 2 mn per st age

CascadeNo.

9

Fi nall queousP1. 00. 90. 90. 90 . 90 . 90. 90 . 90. 9

Fe i nOr gani cAqueousc0 . 002c0 .002(0. 00240 .002400> 600> 8 0 0. l oo0

>12009307016


22/45


23/45

- 15 -UN CLASS IF EDOR NL-LR-DWG. 16767

I O 0

P 902WIa 80WIE 0II-LL6 0

s c I I02 0.4 0.6 OS I .o I .2OF URANIUM EXTRACTEDFIGURE 2 . SELECTIVE EXTRACTION OF THORIUM WITH

PRIMENE JM -T IN KEROSENE


24/45


25/45

0 b

F i n a lPH

TABLE 6 . STRIPPING THORIUM WITH A C I D I C NITRATE AND CHLORIDE SOLUTIONS

P h a se S t r l P P l n gS e p a r a t i o n T h y g / l i t e r C o e f f i c i e n tT ime, sec Aqueous1 Organic S E II

O rg a n i c : 0 . 0 5 M d i ( t r i d e c y 1 P )a mi ne i n k e ro s en e l o ad e d t o 1 . 6 g Thp e r Ti te r f rom a s y n t h e t i c l e a c h l i q u o rC o n t a c t t i m e : 2 min

1 . 1 51 . 2 51 . 3 51 . 4 01 . 4 0

T e m p e ra t u re : R oom (28OC)

4 54 5556555

,~ S t r i p p i n g S o l u t i o n

1 . 57 . 31 3 . 61 7 . 31 9 . 0

148121 52 0 '25,0.08(?)0 . 1 10.230 .440 . 6 7

I :. 0 M N a C l - 0.05 M H S04- - 152 0

1 . 2 01 . 2 51 . 3 01 . 4 01 . 5 01 . 4 51 . 4 5

5 0606065754 070

1 . 66 . 11 2 . 51 8 . 22 2 . 43 0 . 23 0 . 3

4 0 . 0 0 5< 0 . 0 0 50 . 0 2 80.0720 . 1 0 00 . 2 00.52

> 280> 1 2 0 04502502201 5 06 01 9 ?)65604028


26/45

- 1 8 - U N CLASS F EDORNL-LR-DWG. 167684 0

3 0

20

10

0

I I I I I I

0. I M HNOS-0.9M NH,NO,

I . O M N a C l - 0.05M H 2 S 0 4

TE ST CONDITIONS L ISTE D IN TA B L E 6 )

10.0 0. 0.2 0.3 0.4 0.5 0.6 0.7 0.8

FIGURE 3 . ISOTHERMS FOR STRIPPING THORIUM FROM 0 . 0 5 MOf TR IDE CY L P ) AM INE W ITH NIT RA TE AND CHLORIDE SOLUTIONS

g / l Th IN.ORGANIC


27/45

1 9 -3.2.2 S t r i p p i n g w i t h Sodium C a r b o na t e S o l u t i o n s . P r e -l i m i n a r y s t u d i e s h av e be en made on t ho r iu m s t r i p p i n g w i t hsod ium c a r b o n a t e s o l u t i o n s . I n t h e t e s t s d e s c r i b e d i nT a b l e 7, SL t h or i um l o ad e d d i ( t r i d e c y 1 P )a m in e - k e r o s e n es o l v e n t w a s c o n t a c t e d w i t h 8 w/v %* s o d i u m c a r b o n a t e a tv a r i o u s p h a s e r a t i o s .

s t r i p p e d a f t e r 2 m i n c o n t a c t t i m e and 99 a f t e r 1 0 min c on -t a c t t i m e , y i e l d i n g i n each case a c l e a r a q u e o u ss o l u t i o n . A t h i g h e r o r ' g a ni c / a q ue o u s p h a s e r a t i o Ih i g h e r t h or i um l o a d i n g i n t h e aq u eo us a nd a smal le r e x c e s s o fs od iu m c a r b o n a t e , t h o r i u m r em o v al from t h e o r g a n i c p h as e w a sl e s s c o m pl e te b u t t h e r e was some i n d i c a t i o n t h a t b e t t e rr e c o v e r i e s migh t h a v e b e e n r e a l i z e d w i t h l o n g er c o n t a c tt imes .** P r e c i p i t a t i o n of t h or i um o c c u r r e d i n a l l t h e s el a t t e r e x p e r i m e n t s , t h e amount of p r e c i p i t a t e f orm ed i n c r e a s -i n g w i t h i n c r e a s e d c o n t a c t t i m e . Over t h e r a n g e o f c o n d i t i o n ss t u d i e d i n t h e s e p a r t i c u l a r t e s t s t h e d e gr e e o f p r e c i p i t a t i o nv a r i e d f r o m 7 t o 99 .9 % of t h e t f o t a l t ho r i um s t r i p p e d . I nt e s t s w here p r e c i p i t a t i o n o c c u r r e d , t h e p h a s e s e p a r a t i o n w a s ,n e v e r t h e l e s s , r a p i d a nd c l e a n w i t h a l l t h e p r e c i p i t a t es e t t l i n g i n t o t h e a qu e o u s phase .

A t a p h a s e r a t i o o f 9 0 / l a , 95% o f t h e t h o r i u m was

A s a r e s u l t of t h e s e p r e l im i n a r y b a t c h s t u d i e s i t i sb e l i e v e d t h a t sodium c a r bo n a t e s t r i p p i n g c o u l d be o p e r a t e ds u c c e s s f u l l y i n a m u l t i s t a g e s y st e m where more e f f i c i e n tu t i l i z a t i o n of t h e s t r i p p i n g a g e n t w ould b e a c h ie v e d .F u r t h e r t e s t s w i l l be made t o b e t t e r d ef dn e t h e optimum com-b i n a t i o n of s u c h c o n d i t i o n s a s s od iu m c a r b o n a t e c o n c e n t r a t i o n ,f l o w r a t i o s , c o n t a c t t i m e , t e m p e r a t u r e , e t c ,

4 . 0 CONTINUOUS COUNTERCURRENT TESTS

P r e l i m i n a r y d e m o n s t r a t io n of t h e a p p l i c a b i l i t y o f t h eA m e x p ro c e s s f o r s e p a r a t i o n a nd r e c ov e ry of u r a n i u m a n dt h o r i u m from s u l f a t e l each l i q u o r s h a s b e en made i n c o nt i nu o usc o u n t e r c u r r e n t b en ch s c a l e e q u i p me n t . The d e s i g n of t h eequ ipment w a s g e n e r a l l y s i m i l a r t o t h a t u se d i n Dapex p r o c e s st e s t s which a r e d e s c r i b e d i n A pp en di x A o f ORNL-2172 w i t h t h ee x c e p t i o n t h a t pumps were n o t u se d f o r t r a n s f e r r i n g t h eo r g a n i c p h as e f r om s t a ge t o s t a g e . I n s t e a d , a d va n ta g e w a st a k e n of t h e h y d r a u l i c head d e v e l o p e d b y t h e m ix er i m p e l l e r st o p r ov i de i n t e r s t a g e f l ow o f o r g a n i c . The s y n t h e t i c l eachl i q u o r t r e a t e d i n t h e s e t e s t s s e e T a b l e 7 ) . c o n t a i n e d u r a n i u m ,8 w/v s o d i u m c a r b o n a t e = 8 0 g Na,CO, p e r l i t e r .

**Be t t e r r e c o v e r i e s m i g h t a l s o be o b t a i n e d a t h i g h e r t e mp e r a -t u r e s


28/45

TABLE 7 . STRIPPING THORIUM WITH SODIUM CARBONATE SOLUTIONSO rg a n i c : 0 . 0 5 M d i ( r i d e c y l P ) am in e- i n k e r o s e n e l o a d e dt o l o b Th per l i t e r f ro m a s y n t he , t ic l i q u o rS t r i p s o l u t i o n : 8 w / v Na,CO, s o l u t i o nTe mp er at ur e: Room (28OC)

P h a s eR a t i o( o m

99

111 3

1 51818

C o n t a c tT i m e ,min2

1 022

1 022

1 0

PhazcsSepar Lt o nTime, sec1 04 0,10c 10

1 0c10< 1 0< l o

Th, g/Aqueous1 3 . 31 5 . 11 4 , 4 *

8 .8*1 , 5 *6 . 06 .1*0.024*

. i t e rO r g a n i c0 .0720 . 0 1 80 .190 . 3 10.0820 . 4 80.650 . 4 4

' Thor iumS t r i p p e d**( of t o t a l )~~

95998 88 195705972

Thor iumP r e c i p i t a t e d( of s t r i p p e d )007

4 892646 49 9 . 9

* Th or iu m p r e c i p i t a t i o n o c c u r r e d ; a q u e ou s p h a s e w a s f i l t e r e d b e f o r e a n a l y s i s .**Based on t h e e x t r a c t a nd s t r i p p e d o r g a n i c a n a l y s e s .

8 1


29/45


30/45


31/45

- 23 -

TABLE 8. OPERATING CONDITIONS FOR THE URANIUM RECOVERY CYCLE

E x t r a c t i o n S y st emNumber of mixer - se t t l e r s t ages : 3O r g a n i c : d h a s e : 0 . 1 0 M t r i' - n -o c t yf r a min e i n 97% k e r o s e n e -

3% t r r d e c y l - a l c o h o lL ea c h l i q u o r : S y n t h e t i c l i q u o r i d t h 1 . 2 g U , 0 .2 g T h ,1 .0 g F e ( 1 1 ) , 1 . 0 g Fc 111) a n d 4 0 g SO4 p e rl i t e r ; pH 0 .9F e e d r a t e : Aqueous 100 ml/min

Organ ic 25 m l / m i n ,R e s i d e n c e t i m e i n e a c h m i x e r : 1 . 6 rninR e s i d e n c e t i m e i n e ac h s e t t l e r : Aqueous 1 . 5 minO r g a n i c 6 min

S t r i p p i n g S y st em s e e A pp en dix f o r f u r t h e r i n f o r m a t i o n )Number o f s t r i p p i n g s t a g e s : 1S t r i p p i n g a g e n t : A queous s l u r r y of Mi c h i g a n Ch e mi c a l C o .N o . 1 5 c a l c i n e d magnes i t e , 0 .467 M MgO*Feed r a t e : E x t r a c t 25 ml/minMgO s l u r r y 5 ml/min

-

O p e r a t i n g t e m p e r a t u r e : R o o m (32OC)R e s i d e n c e t i m e i n e a c h of t w o c o c u r r e n t mixers: 10-12 rninR e s i d e n c e t i m e i n s e t t l e r : A qu eo us ( s i n g l e p a s s ) 7 .5 minOr ga n i c 14 rnin

*A s a m p l e of t h e s l u r r y was t i t r a t e d w i t h a c i d t h u s g i v i n gt h e t o t a l b a s e s t r e n g t h of t h e s l u r r y wh ich i s e x p r e s s e dh e r e a s e q u i v a l e n t MgO.


32/45

TABLE 9. URANIUM RECOVERY CYCLE DATA

E x t r a c t o n

E x t r a c t i o n S ys te mS t a g e 1S t a g e 2S t a g e 3

2 0 . 3 6 5 . 0 0 . 0 0 5 1 40 .016 1 . 9 CO.005 1200 .0017 0.47


33/45

- 25 -same m agn esiu m o x i d e - o r g a n i c c o m b i n a ti o n ha d r e s u l t e d i ne s s e n t i a l l y c o mp le te (>99 .8% ) s t r i p p i n g u s i n g s i m i l a r con-t a c t i n g c o n d i t i o n s , A l o n g er c o n t a c t t i m e a n d / o r morev i g o r o u s m i x i ng w ou ld p r o b a b l y h a v e g i v e n i mp ro ve d e f f i c i e n c y .A l s o , o t h e r t e s t s ( r e s u l t s n o t p r e s e n t e d ) h av e shown t h a ti n c r e a s i n g t h e t e m pe r a t u re o f t h e s t r i p p i n g sy s t em by a sl i t t l e a s 10C a p p r e c i a b l y i n c r e a s e s t h e r a t e of r e a c t i o no v e r t h a t o b s e rv e d a t room t e m p e r a t u r e . F u r t h e r s t u d y of t h em ag nes ium o x i d e s t r i p p i n g m e tho d i s b e i n g made i n a t w o - s t a g ec o u n t e r c u r r e n t s y s t em a s c o n t r a s t e d t o t h e s i n g l e s t a g eo p e r a t i o n u se d i n t h e s e t e s t s . T h e i m p o r t a n c e o f m i x i n gv a r i a t i o n s , c o n t a c t t i m e , t e m p e r a t u r e , a n d excess magnesiumo x i d e w i l l b e e v a l u a t e d .

. P h y s ic a l o p e r a t i o n of t h e e x t r a c t i o n a nd s t r i p p i n g c i r -c u i t s w i th r e s p e c t t o p ha se s e p a r a t i o n , e t c . w a s s a t i s f a c t o r yt h ro u gh o ut t h e r u n . The o r g a n i c o v e r f l o w from t h e s t r i p p i n gs e t t l e r w a s c l e a r a nd c om p l et e ly d e v oi d o f p r e c i p i t a t e . I ts h o u l d b e em phas ize 'd t h a t t h e r e s i d e n c e times i n t h e e x t r a c -t i o n a n d s t r i p p i n g mi xe rs a nd s e t t l e r s a s show n i n T a b l e 8a r e n o t me a n t t o r e p r e s e n t t h o s e t h a t w ould b e us ed i n a c t u a lp r oc e ss p r a c t i c e . The p a r t i c u l a r c o n d i t i o n s u se d i n t h i st e s t r e s u l t e d f rom a c h o i c e o f c o n v e n i e n t f l o w r a t e s a sd i c t a t e d by t h e s i z e o f t h e c o n t a c t i n g e q u ip m e nt a n d pumpsa v a i l a b l e . O t h e r w ork o n t h e Amex p r o c e s s by t h e P r o c e s sT e s t S e c t i o n h a s sh ow n t h a t much lower r e s i d e n c e t i m e s ,p a r t i c u l a r l y i n t h e mi xe r ,* r e p o s s i b l e w i t h p r op e r o p t i m i z -i n g of t h e m i x in g v a r i a b l e s 791T he m ag ne si um " d i u r a n a t e " s l u r r y d i s c h a r g e d f ro m t h es t r i p p i n g s ys te m w a s c o l l e c t e d i n t h r e e i n c r e y e n t s , w h ich

were f i l t e r e d , washed w i t h w a t e r , a nd d r i e d a t 4OO0C. F i l -t r a t i o n r a t e s f o r a l l t h e s e s am p l es were r a p i d . T he u r a n i umc o nt e n t o f t h e f i l t r a t e ( n o t i n c l u d i ng t h e wash s o l u t i o n ) w a s0 . 0 0 8 g p e r l i t e r , e q u i v a l e n t t o 9 9. 95 % r e c o v e r y o f t h e c o n -t a i n e d u ra ni um i n t h e p r od u ct p r e c i p i t a t e . The U308 c o n t e n tr a n g e d from 75-78% a n d t h e Tho z c o n t e n t w a s o n l y 0 . 0 3 - 0 . 0 5 %( T a b l e l o ,u ran ium p r e c i p i t a t e s l u r r y d i s c h a rg e d f rom t h e o r g a n i cM ea su re me nt o f t h e am oun t o f o r g a n i c e n t r a i n e d * * i n t h e

* A s d e s c r i b e d ab ov e , t h i s d o es no t n e c e s s a r i l y a p p l y t o t h em i x e r s i n t h e m agnesium o x i d e s t r i p p i n g s y st e m w he re a n i n -c rease i n r e s i d en c e t i m e would p resumably have been bene-f i c i a l . Even h e r e s h ow ev er , more e f f i c i e n t m ix in g m ig ht b eu s e d a s a n a l t e r n a t e t o i n c r e a s e d r e s i d e n c e t i m e o r mi g h tp e r m i t a d e c r e a s e i n t i m e .

**The o r g a n i c c o n t e n t o f t h e s l u r r y w a s d e t e r m i n e d by s c r u b b i n ga volum e o f t h e s l u r r y e x h a u s t i v e l y w i t h b en z en e , e v a p o r a t i n gt h e b en ze ne s c r u b s o l u t i o n t o a r e l a t i v e l y s m a l l vo lume , andt i t r a t i n g i t s am ine c o n t e n t . P r e v i o u s s t u d i e s ( u n r e p o r t e d )


34/45

- 26 -

P r o d u c t , A n a l y s i s ,F r a c t i o n U 3 0 8 MgO C 0 3 SO, Thoz1st 7 8 , 3 1 1 . 8 0 . 5 6 0 . 0 5 0 . 0 42 nd 7 4 .8 1 4 .3 0 .4 0 0 . 0 5 0 .033 r d 7 7 . 0 1 2 .8 0 .2 8 0 . 0 5 0 . 05

TABLE 10 . ANALYSIS OF URANIUM PRODUCTS

L o s s o nI g n i t i o na t1ooooc,

6 . 47 . 76 . 4

r e c o v e r y c h a m b e r s e e Append ix A ) showed a l o s s o f 0.0 02 l bo f a mi n e a n d 0 .0 0 7 g a l o f d i l u e n t p e r pound o f U 3 0 8 . S u c hlo s ses w ou ld b e u n i m p o r t a n t c o s t w i s e , S i n c e t h e s l u r r y d i s -c h a r g e f ro m t h e s e t t l e r c o n t a i n e d 0 .0 19 l b o f a m in e a n d 0 .0 67g a l o f d i l u e n t p e r pound o f U 3 0 8 , t h e r e c o v e r y e f f i c i e n c y i nt h e o r g a n i c r e c o v e r y c h am be r w a s a b o u t 90%. I n p r o c e s sp r a c t i c e t h e o p e r a t i o n o f t h e o r g a n i c r e c o v e r y c ham be r may n o tb e n ec e s s a r y s i n c e t h e s e l o s s e s a l s o w ould n o t b e p r o h i b i t i v e .F u r t h e r m o r e , i t i s p r ob a b le t h a t some o f t h e o r g a n i c e n t r a i n e di n t h e s l u r r y c o u l d be r e c o v e r e d f ro m t h e f i l t r a t e f o l l o w i n gp ro du c t f i l t r a t i o n .

4 .2 Th o r iu m Re c o v e r y C y c l eThor ium w a s r e c o v er e d f r om t h e r a f f i n a t e o f t h e u ra niu mrecovery c y c l e u s i n g d i ( t r i d e c y 1 P )a m in e a s e x t r a c t i o n a g e n t .T h i s a m in e w a s s e l e c t e d s i n c e i t p r o v i d e s a f a v o r a b l e combi-n a t i o n o f h i g h t h o r i um e x t r a c t i o n power ( s e e T a b l e s 2 , 3 , a nd4 ) a n d l o w am in e d i s t r i b u t i o n l o s s t o t h e a q u e ou s p h a s e . *

h a ve i n d i c a t e d t h a t t h e r e i s no p r e f e r e n t i a l a d s o r p t i o n o fam in e o n t h e ur an iu m p r e c i p i t a t e . T h u s , d e t e r m i n a t i o n o f t h ea m ine c o n t e n t ' o f t h e s l u r r y o f f e r s a c o n v e n i e n t me th od f o re s t i m a t i n g t h e volum e o f o r g a n i c e n t r a i n e d .*The l o s s ' o f a mine th r ou g h d i s t r i b u t i o n t o t h e a q ue o u s p h a seo n a l b a m i ne / lb Th b a s i s i s i n v e r s e l y p r o p o r t i o n a l t o t h et h or i um c o n t e n t o f t h e h ea d l i q u o r . H en ce , s i n c e t h e t h or i umc o n t e n t of t h i s l i q u o r w a s l o w (/J 0 . 2 g p e r l i t e r ) i t w a sp a r t i c u l a r l y i m p o r ta n t t o c h o o s e a n a m in e w i t h a l o w d i s t r i -b u t i o n l o s s . T he s t e a d y s t a t e d i s t r i b u t i o n l o s s o f d i ( t r i -d e c y l P ) a m i n e t o a 0 . 5 M s u f a t e l i q u o r a t pH 1 h a s b e e nme a s u r e d t o b e a b o u t 5 F p m. t 2 ) Th e l o s s o f P r i m e n e JM-R r e -d i s t i l l e d P ri me ne J M-T)9 t h e o n l y o t h e r a m in e of t h o s e t e s t e dt h u s f a r w h ic h s how ed c o m p a r a t i v e t h o r i u m e x t r a c t i o n p ow er ,w a s me a s u r e d t o b e a b o u t 50 ppm ( n o t p r e v i o u s l y r e p o r t e d ) .


35/45

- 27 -O p e ra t in g c o n d i t i o n s f o r t h e r u n a r e l i s t e d i n T a b l e 11.Th e t h o r i u m w a s e x t r a c t e d w i t h 0 . 0 5 M d i ( t r i d e c y 1 P ) a m in e i nk e ro s e n e , u s i n g t h r e e e x t r a c t i o n stazes a n d a n a q u e o u s / o r g a n i cf e e d r a t i o of 7 /1. Thor ium w a s s t r i p p e d f rom t h e e x t r a c t w i t ha n a c i d i c c h l o r i d e s o l u t i o n ( 1 . 0 M N a C l - 0 , 0 5 M H 2S 04 ) i nt h r e e s t a g e s . * The r u n p roceed ed- fo r 8 h r , w h i a w a s e q u i v a -

l e n t t o a b o u t 5 . 5 c o m p l et e c y c l e s of t h e o r g a n i c p h as e . H e r ea g a i n 9 as i n t h e ur an iu m re c o v er y c y c l e d e s c r i b e d ab o ve , t h er e s i d e n c e t imes o f t h e a qu eo us a nd o r g a n i c p h a s es i n t h es y st e m ( T a b l e 11 h av e no r e l a t i o n t o t h o s e t h a t m ig ht b ep o s s i b l e i n a c t u a l p r a c t i c e . The c o n d i t i o n s c ho se n f o r t h i st e s t were s im p ly t h o s e t h a t w e r e c o n v e n i e n t t o u s e i n t h ea v a i l a b l e s m a l l b e n c h - s c a l e e q u i p m e n t .S am pl es of t h e o r g a n i c a n d a q ue o u s p h as e s f r om t h es e t t l e r of e a c h s t a g e were t a k e n a f t e r a p p ro x im a t e l y 3 , 4,a n d 5 c o m p l e te c y c l e s o f t h e o r g a n i c p h a s e . T he t h o ri u m c on -t e n t of t h e f i n a l r a f f i n a t e w a s C 0 .0 02 g p er l i t e r ( T a b l e 1 2 ) ,a n d t h u s t h o r i u m r e c o v e r y was g r e a t e r t h a n 997b6 A l t h o u g h a n

a p p r e c i a b l e a mou nt of i r o n w a s e x t r a c t e d i n t h e b ot to m e x-t r a c t i o n s tage , mos t o f t h i s i r o n w a s r e j e c t e d f r o m t h eo r g a n i c p h as e a s i t l o a d e d t o a h i g h e r l e v e l w i t h t h or iu m , s ot h a t t h e f i n a l i r o n c o n t am i n a t io n w a s u n i m p o r t a n t .T ho riu m s t r i p p i n g w a s n o t c o mp le te i n t h i s t e s t , w i t ht h e r e c y c l e d o r g a n i c p ha se c o n t a i n i n g 0 .0 8 - 0 .10 g p e r l i t e r .N e v e r t h e l e s s , a s j u s t d e s c r i b e d , t h i s l e v e l of t h or iu m w a ss u f f i c i e n t l y l o w t o a l l o w e s s e n t i a l l y c om p le te t h or iu mr e co v e r y i n t h e e x t r a c t i o n s y s t em .The pr e gn a n t s t r i p s o l u t i o n c o n ta i n e d 1 8 . 1 g Th a n d 0 .1g F e p e r l i t e r , Thor ium w a s p r e c i p i t a t e d f ro m t h i s s o l u t i o nby r a i s i n g t h e pH t o 7 . 0 w i t h ammonium hy dr ox id e. Ammoniar e q u i r e m e n t s were a p p r o x i m a t e l y 0.24 l b NH, per pound Thoz .The p r e c i p i t a t e , w h ic h f i l t e r e d r e a d i l y , . w a s wa s h e d wi t h watera nd d r i e d a t l l O C . T h e t h o r i u m p r o d u c t a n a l y z e d 6 5. 5% T hozO O Z 2 F e , 0.07% C l , a n d 24 S O , . Weight l o s s e s a f t e r i g n i t i o na t 200, 5 0 0 , and 1000C were 7.99 1 1 . 6 s an d 31.8%9 r e s p e c t i v e l y .T he h i g h s u l f a t e c o n t e n t o f t h e p r o d u c t may b e u n d e s i r a b l e ,a nd m et h o d s, o t h e r t h a n c a l c i n i n g , f o r e l i m i n a t i n g s u l f a t e a r eb e i n g s t u d i e d ,P h y s ic a l o p e r a t i o n o f b o t h t h e e x t r a c t i o n an d s t r i p p i n gc i r c u i t s w a s s a t i s f a c t o r y t h r ou g h o u t t h e r u n .

* A s s u g g e s t e d e a r l i e r f o r u r an iu m, o t h e r s t r i p p i n g m etho dsc o u l d a l s o b e u s e d a s o u t l i n e d i n p re v io u s r e p o r t s a nd o t h e rs e c t i o n s o f t h i s r e p o r t ,


36/45

- 2 8 -

TABLE 11, OPERATI NG CONDI TI ONS FOR THE THORI UM RECOVERY CYCLE

Ext r act i on Syst emNumber of m xer - set t l er st ages: 3Or gani c phase: 0.05 M di ( t r i decy1 P) amne i n ker osene-Leach l i quor : r af f i nat e f r om ur ani um r ecover y cycl e +synt het i c ur ani um bar r en l i quor ; * appr oxi mat ecomposi t i on, g/ l i t er, 0 . 2 Th, 1. 0 Fe(I I ) ,1, O Fe( I I I ) , 0. 0004 Us 40 S O 4 ; pH 0 . 9 5Feed r ate: Aqueous 160 m/ mnOr gani c 2 2 . 5 m/ mnResi dence t i me i n each mxer : 1. 3 m nResi dence t i me i n each sett l er : Aqueous 0. 7 m nOr gani c 5 m n

St r i ppi ng Syst emNumber of m xer - set t l er st ages: 3St r i ppi ng agent : 1. 0 M NaCl - 0 . 0 5 M HzSO4Feed r at e: Ext r act 2 2 . 5 m/ mnSt r i p sol ut i on 1. 7 m/ mn

- -Resi dence t i me i n each m xer : 10 mnResi dence t i me i n each set t l er : Aqueous 16 m nOr gani c 8 . 5 m n

*A l arger vol ume of l i quor f o r t hor i um r ecover y was desi r edf or t he t est s t han was avai l hbl e as r af f i nat e f r om t he ur ani umr ecover y cycl e. Hence, addi t i onal ur ani um bar r en synt het i cl i quor was pr epar ed w t h si m l ar composi t i on, Thi s was combi ned w t h the r af f i nat e f r om t he ur ani um r ecover y to gi ve t hedesi r ed vol ume of f eed l i quor for t he thor i um r ecover y cycl e.


37/45

TABLE 1 2 . THORIUM RECOVERY CYCLE DATA

Mater ia lSampledT ho ri um C o e t f i c i e n t sime 0 2 Fe i nTh , g / l i t e r O r ga n i c , E x t r a c t i o n S t r i p i ngampl ing ,* Aqueoush r PH Aqueous I O r g a n i c g / - l i t e r ( E m S O

S t a g e 1 5 0 .90 0 .18 1 . 5 7 0 . 0 0 5 8 . 7 --S t a g e 2 0 .92 0 .041 1 . 5 5 0 . 0 15 3 8 --S t a g e 3 0 .95 < 0.002 0 .57 0 .063 >280 --S t a g e 1 6.5 0 . 9 0 0 . 1 8 1 . 5 5 0 , 0 0 4 8 . 6 --S t a g e 2 0.92 0.035 1 .45 0 . 0 2 1 4 1 --S t a g e 3 0095 < 0.002 0.44 0 .065. >220 --S t a g e 1 8 0.90 0 .12 ---- 0.006 -- --S t a g e 2 0.92 0 . 0 1 1 .02 0 .048 1 0 0S t a g e 3 0.95 < 0 ,002 0.16 0 .075 > 80 ----

S t r i p p i n g S ys te mS t a g e 1 5 1 .45 16 .3** 0 .90 -- -- 1 8

. 1 .25 7 . 1 0 .26 -- -- 2711

S t a g e 2 1.1 0.098 -- --t a g e 3 1 . 1 01 9St a g e 2 1 . 2 5 9 . 5 0 . 3 4 -- -- 281 9

-- --t a g e 1 6 .5 1 .45 2 0 . 6 * * 1 - 1 0S t a g e 3 1 - 1 0 1 . 9 0.098 -- --S t a g e 1 8S t a g e 2S t a g e 3

1 - 4 51 . 2 51 - 1 022.6** 0 .97 --9 .6 0.262 , l 0 .08 ----

233726

' -* 'One comple te cyc le of t h e o r g a n i c p h a se r e q u i r e d a p p r o x i m a t el y 1 . 5 h r .* * P r e c i p i t a t e f or me d on s t a n d i n g o v e r n i g h t .

.


38/45

- 30 -5 . 0 ESTIMATED REAGENT COSTS

U s in g t h e d a t a f ro m t h e c o n t i n u o us c o u n t e r c u r r e n t r u n sd e s c r i b e d a b o ve , r e a g e n t c o s t s h av e be en e s t i m a t e d f o rr e c o ve r y o f u r an iu m a nd t ho r i um fro m t h e s e s u l f a t e l i q u o r sw i t h a mi ne e x t r a c t a n t s . The f o l l o w i n g a s s u m p ti o n s were made:

1. T he u ra n iu m a nd t ho r i u m c o n t e n t s o f t h e he ad l i q u o ra r e t h e same a s i n t h e l i q u o r t e s t e d , i . e o , 1 . 2 g U a n d 0 .2 gTh pe r l i t e r .2 . The l o s s o f t h e o r g a n i c p h as e t h r o u g h e n t r a i n m e n t a n ds p i l l a g e i s 0.05% o f t h e r a f f i n a t e volu me. T h i s e s t i m a t e i sb as ed on r e s u l t s of p r o c e s s t e s t s by t h e P r o ce s s T e s t S e c t i o nw hi ch ha ve a c t u a l l y i n d i c a t e d lower l o s s e s . H ow ev er , t h i sp a r t i c u l a r s o u r c e o f r e a g en t c o s t m ig ht v a r y c o n s i d e r a b l y i nl a rg e - s ca l e o p e r a t i o n a n d w ould b e s t b e ch ec ke d i n a p i l o tp l a n t w h i c h i s o p e r a t i n g c on t i nu o u s ly on t h e a c t u a l l i q u o r s t o

b e t r e a t e d .3 . L oa di ng s o f t h e e x t r a c t a n d t h e s t r i p s o l u t i o n s a r ee x a c t l y t h e same a s o b t a in e d i n t h e c o u n te r c u r r e n t t e s t s .I t s h o u l d be em p ha si ze d t h a t t h e es t imates ma d e h e r e a r ef o r o n l y o n e s e t o f p r o c e s s c i r c u m s t a n c e s . O t h e r p r o c e s s i n ga r r a n g e m e n t s a r e p o s s i b l e , f o r e xa mp le , c h o i c e o f d i f f e r e n ts t r i p p i n g m eth ods or t y p e o f l i q u o r t r e a t e d , w hich c o u l d l e a dt o d i f f e r e n t c o s t s t h a n t h o s e p r e s e n t e d .

5 . 1 Ura ni um Re c o v e r y Cy c l eThe es t i ma t ed t o t a l r e a g e n t c o s t s ( T a b l e 1 3 ) f o r t h eu ra ni um r e c o v e r y c y c l e a r e a b o u t 7 p e r p o u n d o f U 3 0 8 r e c o v e r e d .A pp ro xi ma te ly h a l f t h i s c o s t i s f o r t h e m a gn es iu m o x i d eu t i l i z e d f o r s t r i p p i n g an d t h e ba l a n c e f o r l o s s e s o f t h e am in ea nd d i l u e n t .

5 .2 Th o ri u m Re c o v e r y Cy c l eFor t h e t ho r i um r ec o ve r y c y c l e , t h e t o t a l r e a g e n t c o s t s ,i n c l u d i n g t h e c o s t o f ammoaia f o r p ro d u c t p r e c i p i t a t i o n , a r ee s t i m a t e d ( T a b l e 1 4) t o b e a b o u t 1 3 6 p e r p o un d of Thoz re-c ov er ed . F i f t y - f o u r p e r ce n t o f t h i s c o s t i s c o n t r i b u t e d byes t ima tes o f e n t ra i n m e nt an d s p i l l a g e l osses of t h e o r g a n i cs o l v e n t , t h e a mou nts b e i n g r e l a t i v e l y g r e a t e r f o r t h o r iu mt h a n f o r u r a ni u m ow i ng t o t h e lower c o n c e n t r a t i o n of t h o r i u mi n t h e head l i q u o r . The s e n s i t i v i t y o f o v e r a l l c o s t s t o t h e s el o s s e s w i t h d i l u t e l i q u o r s a g a i n p o i n t s u p t h e ne e d f o r p i l o t -s c a l e s t u d i e s o f t h i s f a c t o r . I t w ou ld b e e q u a l l y i m p o r t a n t t od e t e rm i n e w h et he r t h e a c t u a l l o s s e s m i g h t be h i g h e r t h a n e s t i -mated or w h e th e r t h e y c o u l d b e h e l d lower b y , e , g . , p r o v i d i n gs u f f i c i e n t ho ld -up t i m e f o r t h e r a f f i n a t e p r i o r t o d i s c a r d .


39/45

? C

ChemcalMgO

TABLE 13. ESTI MATED REAGENT COSTS FOR URANI UM RECOVERY

Consumpt i onUrani um preci pi t at i on

Tri ( i so- oc- t yl ) amne*

Tot al organi c phase

Di str i but i on t o raf f i nat e("25 PPm

Ent rai nment and spi l l age**

Consumpt i on,I b/ l b U z O n0, 660. 017

0. 043 gal / l b U, 08

80 1. 4

45d/ gal *** 1. 9Tot al 6. 9

*Tr i - n- octyl am ne, r at her t han t r i ( i so- octyl ) amne, was actual l y used f or t he demonst r a-t i on r un.si der abl y bet t er t han that of t r i - n- o t yl amne, and si nce t he ext r act i on per f or mance ofwas postul ated f or thi s est i mat e. The l ' i sted cost of t he amne (80&/ l b) i s an est i mateby t he manuf act urer of a r easonabl e sel l i ng pr i ce f or - t he compound, assum ng that i twoul d be produced i n l arge quant i t i es. At t he pr esent t i me i t i s avai l abl e onl y i nexper i ment al l ot s, and unt i l quant i t y producti on i s real i zed, co t of t he am ne woul d,of cour se, be subst ant i al l y hi gher . ' However , t i s evi dent t hat assumpt i on of a costeven doubl e the above val ue, i . e. , $1. 60/ l b, woul d not r ai se the est i mat ed cost of t heam ne l oss to a prohi bi t i ve val ue.

However , s i nce t he suppl y potent i al (4) of tr i ( i so- octy1) amne appear s con-t hese t wo compounds have proved to-e al most i dent i cal , the use of t r i ( i so- octy1) amne

**Organi c l oss by ent rai nment and spi l l age est i mated at Oe05%of t he r af f i nate vol ume:***Based on kerosene cost of 14d/ gal and t r i decyl al cohol cost of 23g /lb No char ge i smade f or t he t r i decyl al cohol l ost t hr ough di st r i but i on t o the aqueous phase. Thel oss of t r i decyl al cohol f romdi(2-ethylhexy1)phosphoric aci d - ker osene sol vent hasbeen measured t o be 410 ppml o), suggest i ng t hat t he l oss f r om t he amne-ker osenesol vent i s al so very l ow and negl i gi bl e cost w se.


40/45

TABLE 14. ESTI MATEDREAGENT COSTS POR THORI UMRECOVERY

Consumpt i on,l b/ l b ThOz2. 90. 250. 240. 022

0. 26 gal / l b Tho2

Uni t Cost ,L/ l b0. 81. 55. 8

80*

276/ gal ***

ChemcalWaClH2SO,,NH3Di ( t r i decy1 P) am ne

Or gani c phase

Consumpt i onThori um st r i ppi ngThori um st r i ppi ngThori um pr eci pi t at i onDi str i but i on to r af f i nat e( 5 PPmEnt rai nment and spi l l age**

0.41. 41. 8

7. 0Tot al 12. 9

*Di ( t r i decyl P) amne i s now avai l abl e onl y i n exper i ment al quant i t i es. As w t ht r i ( i so- octy1) am ne ( see f ootnot e, Tabl e 13) , t he sel l i ng pr i ce of t he compound woul dbe sensi t i ve t o t he l evel of product i on. The pr i ce l i st ed i s t hat est i mat ed by themanuf act ur er f or l ar ge- quant i t y product i on.**Or gani c l oss by ent r ai nment and spi l l age est i mated at 0. 05% of t he r af f i nate vol ume.

***Based on kerosene cost of 14b/ gal .

.a (..

I t


41/45


42/45

- 3 4 -

APPENDIX A

Des ign a n d O p e r a t i o n o f t h e M ag nesi um O x id e S t r i p p i n g Sy s te m

T he magnesium o x i d e s t r i p p i n g s y s t em u s e d f o r t h e u r an iu mr e c o ve r y c y c l e s e e p .2 1) c o n s i s t e d o f t w o c o c u r r e n t b a f f l e dm i x e r s , a s e t t l e r , a n d a n o r g a n i c r e c o v e r y c ha mb er c o n n e c t e dt o g e t h e r a s show n i n F i g . A-1 . I n o p e r a t i o n , t h e o r g a n i c ex-t r a c t a nd t h e ma gn esi um o x i d e s l u r r y were f e d t o t h e f i r s tmi x e r ( A ) f ro m w h i ch t h e y p a s s e d t o t h e s e c on d mixer ( B ) andt h e n t o t h e s e t t l e r ( C ) . R e s i d e n c e t i m e i n e ac h mixer w a sa p p r o x i m a t e l y 1 2 m in . T he s t r i p p e d o r g a n i c p h a s e o v e r f lo w e df r o m t h e s e t t l e r a n d w a s r e c y c l e d t o t h e e x t r a c t i o n s ys te m.The s e t t l e r w a s p r o v i de d w i t h a v e r y s l o w - t u r n i n g s t i r r e r 9w hi ch a i d e d i n d is en ga g em e nt o f o r g a n i c fr om t h e s l u r r y . T hem agn esiu m " d i u r a n a t e " s l u r r y w a s pumped f rom t h e bo t to m of t h es e t t l e r a nd f e d t o t h e t o p o f t h e o r g a n i c r e c o v e r y c ham ber ( D ) .S l u r r y w a s pumped f ro m t h e bo t t o m o f t h e o r g a n i c r e c o v e r ychamber t o a f i l t e r . Bo th t h e C a n d D c h a mb e r s w e r e e q u i p p e dw i t h c o n i c a l - s h a p e d b o t t o m s t o e n s u r e pr o p e r d i s c h a r g e o f t h es l u r r y s o l i d s . S l u r r y w a s pumped from C t o D a t a c o n s i d e r -a b l y f a s t e r r a t e t h a n i t w a s pumped from D , O p e ra t i on i n t h i sm an ne r a l l o w e d c o n t i n u o u s o v e r f l o w o f a q u e o us * ( a n d r e c o v e r e do r g a n i c ) f r o m D which w a s r e c y c l e d t o C . The l e v e l of t h ei n t e r f a c e i n C w a s c o n t r o l l e d by t h e r a t e a t w hich s l u r r y w a spumped from D o

S u cc e ss i n a v o i d i n g em u l s i o n f o rm a t i o n w h i l e c o n t a c t i n gt h e m agnesium o x i d e s l u r r y w i t h t h e e x t r a c t depends on ma in -t a i n i n g t h e o r g a n i c ph as e co n t i n uo u s i n t h e mixers . S i n c et h e o r g a n ic / a q ue o u s f e e d r a t i o t o t h e s y s te m i s h i g h , i . e . ,4 5 / 1 t h i s c o n d i t i o n i s n o t d i f f i c u l t t o m a i n t a i n , a l t h o u g hsome ca re s h ou l d be t a k en i n s t a r t - u p t o e n s u r e t h a t t h eo p p o s i t e c o n d i t i o n , i . e . , a q ue o u s p h a s e c o n t i n u o u s , d o e s n o tr e s u l t . T h i s i s b e s t a cc om p li sh ed by f i l l i n g t h e m ix e rs w i t ht h e o r g a n i c ph as e an d s t a r t i n g t h e s t i r r e r s b e f o r e b e g i n ni n gf e e d o f t h e m ag ne si um o x i d e s l u r r y .

The magnesium o x i d e s l u r r y u se d i n t h i s r u n w a s p r e p a r e dby d i s p e r s i n g M i ch ig an No, 1 5 c a l c i n e d m ag ne si te ** i n water .

* S i n c e t h e ur a n i u m p r e c i p i t a t e s e t t l e d f a i r l y r a p i d l y i n D ,t h e aq ue ou s o ve r f l o w c o n t a i n e d e s s e n t i a l l y no s o l i d s .

**The s o u r c e of t h e m ag ne si um o x i d e u s e d f o r s t r i p p i n g ur an iu mf ro m a mi ne s ca n b e a n i m p o r t an t v a r i a b l e s i n c e v a r i o u ss am pl es hav e shown d i f f e r e n t d e g r ee s o f r e a c t i v i t y f o r t h i sp ur po se , I n a d d i t i o n t o No. 1 5 c a l c i n e d m a g n e s i t e ( M i ch i ga nCh e mi c a l C o o ) o t h e r commercial magnesium o x i d e s am p le s i nt h e same p r i c e r a n ge w hich h av e g i v e n s a t i s f a c t o r y s t r i p p i n gr e s u l t s i n c l u d e N o . 5 c a l c i n e d m a g n e s i t e ( M i c h i ga n C h em i ca lCo.), c a l c i n e d m a g ne s it e No. 2665 ( W e s t v a c o ) , a nd s y n t h e t i cm a g n e s i t e c a l c i n e d L-2-65 ( D o w Ch e mi c a l C o . ) ,


43/45

i, i

UN CLA SS IF I DORNL-LR-DW 16770- 00 RPM -400 R P MP IO RPM

MAGNESIUM DIURANATESLURRY, - 4 0 m l / m i n IT'+ MAGNESIUMP I = FINGER PUMPP 2 = MICROBELLOWS PUMPCAPACITY O F THE SETTLER - AQUOUS 300 m l ; ORGANIC 350 m lCAPACITY O F T H E ORGANIC RECOVERY CHAMB ER - 650 m l FILTER

DIURANATESLURRY TO5 m l l m i n

FIGURE A - I . MAGNESIUM OXIDE STRIPPING SYSTEM


44/45

- 3 6 -Pr i or . t o use t he sl ur r y was "homogeni zed" i n a War i ng bl ender .Thi s pr ocedur e was adopt ed si nce, i n pr el i m nar y t est s, somedi f f i cul t y had been encount ered i n pumpi ng a uni f or m sl ur r ybecause of set t l i ng out of t he l ar ger si zed par t i cl es i n t hef eed l i ne. The probl em of pumpi ng a uni f or m sl ur r y i s un-doubt edl y much more di f f i cul t i n t he smal l - scal e exper i ment alequi pment used wher e t he sl ur r y f eed r at e i s onl y 5 m/ mnt han i t woul d be i n pl ant - scal e equi pment wher e the f l owvel oci t y i n t he f eed l i ne woul d be much hi gher . I n l ar gescal e oper at i on, i t i s doubt f ul t hdt "homogeni zat i on" of t hesl ur r y woul d be necessary.

APPENDI X BDescr i pt i on of Reagent s

Am ne S- 24: bis(l-isobutyl-3,5-dimethylhexyl)amine

Am ne 9D- 178: dodecenyl Pr i mene 81

CH3 CH31 1 RH rCH3 CH3 R 1

wher e R + R' + R = 11- 14 car bon at oms


45/45

thorium recovery

Documents