US3009767A - Separation of transuranic elements from rare earth compounds - Google Patents

Description

i l P i l t United States Patent 3,009,767 SEPARATION OF TRANSURANIC ELEMENTS FROM RARE EARTH COMPOUNDS Truman P. Kohman, Chicago, 111., assignor to the United 7 States of America as represented by the United States Atomic Energy Commission No Drawing. Filed Sept. 24, 1945, Ser. No. 618,408

17 Claims. (Cl. 23-145) The present invention relates to a process for the separation of certain transuranic elements from 4f-type rare earth and alkaline earth compounds and other impurities. More particularly, it is concerned with the separation of neptunium and plutonium from rare earth fission prodnets and other impurities present in carrier precipitates by subjecting the latter to extraction with a solution in which the neptunium and plutonium compounds present in said precipitates are soluble, but in which the rare earth and alkaline earth compounds are insoluble, or substantially so.

It is known that plutonium can be produced in small quantities by the bombardment of uranium metal with slow or thermal neutrons. The designation plutonium or element 94 as used throughout the present description refers to the transuranic element having an atomic number of 94. The expression 94 means the isotope of element 94 has an atomic weight or mass of 239. Similarly, the terms element 93 or Np refer to the new element known as neptunium having an atomic number of 93.

Uranium is composed of three isotopes, namely, U U and U the latter being present in excess of 99 percent of the whole. When U is subjected to the action of slow or thermal neutrons, a fourth isotope, U is produced having a half-life of 23 minutes and undergoes beta decay to Np which decays further by beta radiation with a half-life of 2.3 days to yield plutonium. In addition'to the formation of the transuranic elements, neptunium and plutonium, there are simultaneously produced other elements of lower atomic weight known as fission fragments. These fission fragments are composed of two distinct element groups, i.e., a light and heavy element group. The light group contains elements having atomic numbers of between about 35 and .46 while the heavier group is composed of elements of atomic numbers varying between about 51 and 60. The elements of these groups as originally produced are considerably overmassed and under charged and hence are highly unstable. By beta radiation, however, they quickly transform themselves into isotopes of these various elements having longer half-lives. The fission fragments and their resulting decay products are commonly known as fission products.

The various radioactive fission products have half-lives ranging from a fraction of a second to thousands of years. Those having very short half-lives may be largely eliminated by aging the material for a reasonable period before handling. Those with very long half-lives do not have sufficiently intense radiation to endanger personnel by moderate shielding. On the other hand, the fission products having half-lives ranging from a few days to a few years have dangerously intense radiations which cannot be eliminated by ageing for practical storage periods. These products are chiefly radioactive isotopes of "ice Sr, Y, Zr, Ob, and Ru of the light group and Te, I, Cs, Ba, La, Ce, and Pr of the heavy group.

It may be readily seen that plutonium produced as generally set forth above is contaminated with considerable quantities of uranium and fission products. In fact, the plutonium constitutes only a very minor portion of the irradiated mass i.e., rarely more than about one percent thereof by weight and not infrequently as low as one or several parts per million. In view of such a low concentration of plutonium in the irradiated metal, it becomes apparent that the procedure employed to recover that element must be highly efficient in order to be at all practicable.

There have been devised a number of procedures for the removal and concentration of plutonium from extremely dilute solutions thereof. In general, such methods involve the formation of various insoluble compounds in said dilute solutions in which the compounds are capa ble of carrying plutonium in a lower valent state not greater than 4, usually 3 or 4. The carrier precipitate and plutonium thus obtained are then dissolved and the plutonium oxidized to a valent state greater than 4, usually the hexavalent state, in which state of oxidation it is soluble in the presence of said carrier. Under these conditions, the plutonium remains in solution and the fission products are removed when the carrier compound is precipitated. Thereafter, the dissolved plutonium is reduced to a valence state in which it is carriable by the aforesaid or other carrier and removed from solution in the form of a carrier precipitate which may again be dissolved and the plutonium purified further if considered necessary or desirable by repeating the above cycle. This procedure obviously is cumbersome and time consuming since it requires a number of such steps in order to effect a substantial removal of fission products and other impurities.

It is an object of the present invention to provide a process by which plutonium and neptunium can be more efficiently separated from impurities such as, the rare earth and alkaline earth fission products normally associated therewith than has been afforded by prior methods.

A further object is to provide a process whereby it is possible to separate plutonium and neptunium from said rare earth and alkaline earth fission products without the utilization of involved oxidation-reduction steps formerly required to effect such separations.

A still further object is to provide a new process for the separation of the aforesaid transuranic elements from solutions containing uranium fission products, which involves first the simultaneous utilization of separate carriers for said transuranic elements and for fission products and thereafter employing a solvent which is capable of selectively extracting the transuranic elements and carrier therefor, leaving behind the fission products and carrier therefor in the form of a substantially insoluble residue.

Further objects will be apparent from the present description.

It has now been discovered that when carriers containing plutonium and neptunium, such as the tetrafluorides and dioxalates of thorium and uranium (+4 valence), are extracted at elevated temperatures with a solution of ammonium fluoride, ammonium oxalate, or a mixture thereof, the rare earth fission products as well as other im- Patented Nov. 21, 1961.

purities present therein may be readily separated from the neptunium and plutonium since the aforesaid rare earths and impurities are substantially insoluble in said solution whereas plutonium and neptunium as well as carriers of the above mentioned class are easily soluble therein. Otherwise expressed, the process of my invention may be specifically represented in substance as follows:

wherein B represents the oxalate or fluoride ions and RE stands for the rare earths present in the carrier precipitate.

In accordance with a preferred embodiment of my invention, hydrogen fluoride is added to an acid solution of neutron irradiated uranium which has previously been subjected to the action of a suitable reducing agent such as, for example, sulphur dioxide, sodium nitrite, or ferrous ammonium sulphate in order to completely reduce the neptunium and plutonium present to the +4 or carriable state. In addition to the aforesaid components, such a solution likewise contains rare earth and alkaline earth fission pnoducts, a fission product carrier, and thorium or uranous ions depending on the particular plutonium car.- rier which it is desired to employ. On addition of the hydrogen fluoride, a precipitate of thorum fluoride, or uranium 'tetrafluoride is formed carrying with it the hubrides of plutonium and neptunium together. with the insoluble fluorides of the rare earth fission products and their carrier. The precipitate thus formed is. then separated by filtration or other convenient means after which it is extracted with an aqueous solution of ammonium fluoride, ammonium oxalate, or a mixture thereof at elevated. temperatures such as, for example, from about 70 to 100 0., preferably at about 80 to 90 0, thereby extracting the thorium or uranium carrier component neptunium, plutonium, and a small quantity of rare earth fission products and carrier from said precipitate leaving behind as a substantially insoluble residue the fluorides of the rare earths and carrier therefor. To the solution thus formed is added a suitable mineral acid such as, for example, nitric acid to precipitate plutonium, neptunium, thorium fluoride,'or uranium tetrafluoride and a greatly reduced quantity of rare earth fission products and carrier, In this connection the normality of the solution'from which the plutonium and neptunium are precipitated may v'a'r'y between'the range, 0.01 to 10 N. In general, however,

it has b'een found preferable to employ acidity ranges of between about 0.1 and 1.0 N.

Further separation of the neptunium, plutonium, and thorium, Oruranium fromrare earth fission, products and carrier can be readily accomplished by repeating' the above cycle. After therare earths have'thus'beenremove'd, the.

thorium fluoride, or uranium tetafluoride carrriier can be separated from the neptunium and plutonium by. means of any of several suitable methods. It is preferred, however, to accomplish this object by metathesizingsaid carrier with strongalkali which involvesreacting the carrier.

precipitate with an alkali metal hydroxide-.such -as,for

example, potassium or sodium hydroxides, tq yield thoriw um or'uranious hydroxides, either of which is readilyv soluble in nitric acid. The carrier precipitate which is.

converted by this treatment to the hydroxide is then washed with water to remove any fluoride ions which.

might be present after which it is dissolved in a suitable oxidizing medium such as, for example, one. consisting of a mixture of nitric acid and potassium dichromate whereby the valence of the neptunium and plutonium contained therein is changed to the +6 state.

In the event thorium has been used as a carrier, the plutonium and neptunium may be precipitated by adding sodium acetate to the solution to form sodium plutonyl acetate and sodium neptunium acetate which are relatively insoluble compounds, leaving thorium in solution.

If uranium tetrafluorideis. employed asv a ca r er, thesolu: tion which has been subjected to the oxidizing action of the nitric acid-potassium dichromate mixture contains neptunium, plutonium, and uranium in the hexavalent state and hence separation of the latter cannot be efiected until the neptunium and plutonium have been selectively reduced to the +4 valence state. This can be accomplished by introducing into the solution a suitable reducing agent such as, for example, sodium nitrite or sulphur dioxide whereby the valence ueptunium and plutonium is changed from +6 to +4 while uranium is unaffected. The plutonium and neptunium. can then be removed from ut on. e a qn o he da e o peroxidein a known manner. 1 i v 7 When. the. oxalates of. thorium oruranium'are employed as carriers for plutonium in the process ofmy invent-ion, procedures slightly difierent, from those set forth. above should be utilized; in separating said, carriers from the neptunium and plutonium. Thus, after the rare earth fission products and other impurities have been removed,

' the carrier precipitate which consists of thorium, or unan:

ferrous ammonium sulphate, -or sulphundioxide whereby,

ium. oxalates, neptunium, and plutonium is dissolvedin a mixture of nitric acid and potassium dichromatei Inthe case of thorium carrier precipitates, the plutoniumam neptunium present therein are oxidized. to, the, +6, state and as such maybe separated from thorium by the addition of sodium acetate to form insolublesodium plutonyl acetate and sodium neptunyl acetate, As -an alternate. method, the thorium can. be removed from solution, by the addition of a suitable source of fluorideoroxalate ions. With ur nium carrier precipitates, the whole is dissolved in a mixture of dichromate and nitricacid-to oxi-. dizethe. uranium, plutonium and neptuniumtoa valence. of +6, To the resulting solution is theuyadded a. sui t able redueing agent'such as, for example, sodium tnitr ite,

the plutonium and neptuniumpresent therein are-r d ce .d to the +4 valence state. Under these. conditions p lu toniuin and neptunium can readily be removed from the solution in the form of their iodates or peroxideshin -a; known manner leaving the uranium in sqlutiqn The'quantityo'f fission product carrier utilized should. not, in generahexceed a concentration greaterthan approximately ten times the amount of plutonium onplut'oniurn carrier present. 'In. the majority von.instancesp however, it is, preferable-to employ-said fissionproduct carrier in an amount substantially. equivalent to the,eou.-. centratioh of thorium or uranium carriers: utiliuedg. Ifr osi f fission p duc a e 9--.p ,utQ !m. .plur tonium carrier greater. than ten to one are used,;it; will be bserv d iw v if i lt-w.-re eq mhc.

plutonilu'n 'from the"fission product carrier.- precipitate wing to the. fact that the plutonium isisubstantiallyen solution,- .of, ammonium. fluoride or ammonium. oxalate.

As examples I of suitable rare earth, and alkaline-earth; fisn'p r duq c ie here m y; be mentio ed he fluorid s.

and oxalates' of lanthanum, ceriu.m (+3 valence), strum, 11111.11, 9 1 um .v um; n e ik o her cqmpound 'of fission product elements. which areinsolublejin-the ammonium oxalate or fluoride solution and insoluble in the initial plutonium solution from I is carried, also may beused. I

In regard to the strengthof the ammonium fluoride or ammonium oxalate solutions utilized, in. carrying-out the,

PT$$ d my nven on. itv m y g n ra be sa d: hat;

these twosaltsor a mixture thereof,shouldipreferablybe,

present in quantities suflicient to provide :a saturatedsolu tion'at about 25C., audit is to be-stricflymnderstood that the expression aqueous saturatedgsolution? appearing; in certain of. the appended claims is tobe constrqled as ai saturated solution of either of the a foresaid' aH or; 31 1 ture thereof at the above indicated temperature. 7

Theuwor'd carrier, as generally considered, may be which the plutonium In instances where plutonium and neptunium are present in macro amounts, i.e., about 50 mg. per liter and above, it is unnecessary to employ a carrier therefor since these elements will precipitate satisfactorily together with the rare earth fission products when hydrogen fluoride, oxalic acid or other suitable acid is added thereto. The

precipitate thus formed can then be extracted with an aqueous solution of ammonium fluoride or ammonium oxalate in accordance with the procedure outlined above to eifect a direct separation of neptunium and plutonium from the rare earth fission products and other impurities.

Where relatively large concentrations of neptunium are present'and it is desirable to separate the same from plutonium, this object may be readily accomplished by selectively oxidizing the neptunium to the +6 or noncarriable state by the action of a mixture of sodium bromate and nitric and/ or sulphuric acids at a temperature of about 50 to 70 C. for a period not to substantially exceed ten to fifteen minutes. Under such condi tions the plutonium remains in the +4 or carriable state, and can be removed from the solution by merely adding hydrogenfluoride or oxalic acid provided the plutonium is present in macro quantities; if not, it can be satisfactorily separated by means of a suitable carrier such as, for example, thorium fluoride.

The present invention may be further illustrated by the following specific examples:

Example I The resulting mixture was agitated at 50 C. for two hours and then cooled to about 25 C. and agitated for an additional two hours after which the precipitate thus formed, containing plutonium and rare earth fission products, was separated by filtration. The residue thus ob tained was washed with 30 milliliters of a solution, 0.015 M in oxalic acid and l M in nitric acid. The washed precipitate was next dissolved in 950 milliliters of 0.3 M ammonium oxalate, and the resulting solution heated with agitation for about one. hour at 75 to 85 C. The'hot solution was then filtered to remove the rare earth and other insoluble oxalates present after which 3.05 liters of N nitric acid was added to the filtrate. The acidified solution was next heatedat 75 C. for one hour in the presence of agitation, and then cooled to 25 C. and stirred for one hour. During this treatment a precipitate formed consisting essentially of plutonium, some neptunium, thorium oxalate, and a greatly reduced quantity of rare earth fission products and other impurities. Specifically, it was found that 99 percent of the rare earth fissionproducts, 99.7 percent of the alkaline earths, and 75 percent of the zirconium present had been removed from the original precipitate in one cycle.

Example 2 i To 4 milliliters of a solution containing03 mg. of

'Ih+ as thorium nitrate, 0.3 mg. of La as lanthanum nitrate, 600 counts/minute of plutonium, and 6,000 counts/minute of neptunium, was added suflicient hydrofluoric acid to render the resulting solution approximately 6 N after which the precipitated fluorides were centrifuged, and the supernatant liquor decanted. The

residue was next washed with 1 milliliter of water, centrifuged, the supernatant layer decanted, and the washed precipitate extracted with 5 milliliters of 10 N ammonium fluoride for 1 hour at 80 C. while agitating. The mixture was then cooled, centrifuged and 5 milliliters of nitric acid added to the supernatant liquor. As a result, a precipitate of thorium fluoride was formed which carried with it about 92 percent of the plutonium and approximately 93 percent of the neptunium originally present. Also, approximately 95 percent of the lanthanum percent in the original precipitate was removed in one cycle.

Example 3 The procedure and conditions employed were identical in all respects with those utilized in Example 1 except for the fact that the solution used to extract the thorium oxalate precipitate consisted of 950 milliliters of 5 N ammonium fluoride to which had been added suflicient ammonium oxalate to produce a saturated solution at 25 C. The quantity of rare earth fission products and alkaline earths removed from the thorium oxalate precipitate in one cycle amounted to 96 and 98 percent respectively.

- While the examples given above are illustrative of certain specific applications of my invention, it should be particularly understood that I do not desire to be limited thereto since it will be apparent to those skilled in the art that said invention is susceptible of numerous modifications without departing from the scope thereof. In general, it may be said that any process involving the utilization of ammonium salt solutions of the aforesaid type to separate plutonium and/ or neptunium from rare. earth compounds is to be regarded as lying within the scope of my invention.

What is claimed is; 1. A process for the separation of transuranic values selected from the group consistingof plutonium and neptunium values from 4f-type rare earth and alkaline earth values which comprises extracting at elevated temperatures a solid composition containing said transuranic values, a carrier for said transuranic values selected from the group consisting of the oxalates and fluorides of thorium and uranium (+4 valence) and an impurity of the group consisting of rare earth and alkaline earth values and a carrier therefor selected from the group consisting of lanthanum fluoride, cerium trifluoride, strontium fluoride, calcium fluoride, yttrium fluoride, lanthanum oxalate, cerous oxalate, strontium oxalate, calcium oxalate and yttrium oxalate, with a solution of an ammonium salt selected from the group consisting of ammonium fluoride and ammonium oxalate, removing the insoluble matter which consists essentially of rare earth'and alkaline earth values and carn'er therefor, addmg a mineral acid to the resulting solution to precipitate said transuranic values and the carrier for these transe uranic values together with a greatly decreased concentration of rare earth and alkaline earth values, and repeating the above cycle to eflect further separation of the transuranic values and carrier therefor from said rare earth and alkaline earth values.

2. A process forthesepara'tion of transuranic values selected from the group consisting of plutonium and neptunium values from 4f-type rare earth and alkaline earth values, which comprises extracting at elevated temperatures a solid composition containing essentially said transuranic values, a carrier for said transuranic values selected from the group consisting of the oxalates and fluorides of thorium and uranium (+4 valence), and rare earth and alkaline earth values and a carrier therefor selectedfrom the group consisting of lanthanum fluoride,

solution to precipitate said transuranic values and the carrier for these transuranic values together with a greatly decreased concentration of rare earth andalkaline earth values, and; repeating the above cycle to efieet further separation of saidtransuranic values and' carrier therefor from said rare earth and alkaline earth values.

3. A process for the separation of'transuranic valuesselected from the group consisting of plutonium and 'nep' tunium values from 4f-type rare earth and alkaline earth v ues Whi omp s s x ct ng a temp ratures of b weenehou fio nd Ga so id:sempo itioucontainr s ssen ally aid an rani al e ac rien fiortsaid:

a s n p c ues e ec om the. oup onsist ng-of:

l q-.- ?fisl q. ,a d flu des of t or um and uranium 1+4, el nse an a e, an a k lin ar h; values-and. a. ca i he eto: se e ted rom th oup consistin fln z y mfl da W i m t flu r d st nti m-fluoride, qa s um flu ide t r u fluoride, lanthanum oxalate, cerous oxalate, strontium oxalate, calcium oxalateanglyttr um oxa a h; a. so ution of anv mmonium salt elec ed r m, e r u o i in of' mmonium fluori e and aminoniumpoxalate, removing the insoluble matter, which consists essentially, ofrare ear h and alkaline earth,

values andv carrier therefor, adding, nitric acid togthe -reslllting solutionto precipitate said transuranic values and: the

carrierfor these transuranie values together with a greatly 'decreased concentration, of rare earth and alkaline earth valu s, and re a in th b ve c c e t si s further separation of said-transuranicvalues, and; zearr ier therefor from said rare earth and akalineearth values,

4. A process for the separation fytransuranioavalues s ws rfrern her wp c ns t n qf-plut n uma unepnriiu ta u st m r pe a -earth nd lka i e-earth values which comprises extracting, a t,f temperatures ofxbeween h w '8 so slp wnpo i oo o tain:

n: s entia y aids ransur ni va ue ca rier .-.sa d, transuranic :v alues selected from the group consisting of e a t s qdr uqr de r t-th tii ml nd r ium valence-and rare earth and alkaline earth values and x at e her st ewe mmc hessronpcons st ng of cerous oxalate, strontium oxalate, calcium, oxalateand; lvttr v 1 ox l t "w th a lu on: t u-.' ammmium sa lwt i r m e. a uponsrist n ofta mo ium-fluoride ant mmoniums xa te. r mov ue hens b lmauer w i v n sts: se t ll t er art al al nert values and carrier theretor, adding-nitric aeid-to the esult ng ut o a r de te sa stans ranis valves.

an hs sr is q h sns ranis alue o ther with ;s wd c eas ic ns ntra Quays ear hiandialsaf ine at h: amcsa stn w tin bqve et e fect ur e par t on; qt sa d; r nsun n q alr e aa sl-t arlier, thereiorfrqmsaidmare earth and alkaline earth values,

A -99w he, t p ra nv Qt ra s ra oal e selected from the group consistingofplutonium and nep tunium valuesvfrprn 4 f-typeJarewearthand; alkaline-earth values, which comprises extracting .atalmperatureofi be; tween about 70;and .10 0 (2., a,solid compqsition,contaim, n ts s nt 'll an r nie elusa Harr ero aid trans:

uranic valuesl selected, from the group consisting; of 1 the oxalates. andffluorides of thorium and. uraniurn- (+4 vanse), nd a e e thi ndtalkalinev r hva an la asthanurncarrier therefor, with a saturated aqueous solution of n ammon m lts ss edi pm e rwr con tns of o iflp r e an mu .w ii m. x ter mo n v e w e' 755 andyttniumoxalatwwith a solution of ammonium'salt t to alue 4 a ues; w i h? i st ne at tsnm wtss 9 u ns 9.0 so id o tain n es nti lly a r ss en alues th s ate. fo ans r n v lussf uu m te a d, al alin va es ands (+3. m sses) carrier therefor with, an aqueous. saturated solution of ammo ium oxalate, e ov ng. t e s ub e m tter: o i t fiswn y o ra w th n a ka ine va ues, and the carrier therefor, adding nitric acid; tot-he resulting solution to. precipitate val es, nd, he horium: o a te to; these. a uranie alu o e her-w th s fl deceased conc ntr t on o ar and alka in values, and. peatin t aboye W916 o: lim fur he s pa ti n o said w ts an thor um-o ala f om said rm e r h aas ka ne a ues, r

t- A Pswsror he se arat on oi ra sur values el atsd. he r posm ns o lp q mend. Pfl Qm l 1 -fi fiy w e' a th anti lka in v ue which em es -e t a in at 1IHPK3JWM- Qt: be w en about-89 and C- s id, W th! f winin s ent all sa d-Hsn wan c values a th r um Q de for s idtmnsumn e em n s; and, and a k ine salu e o h-s aqueous s u ate o ut o o ammon m. fluoride, removing the insoluble ,matter essent al yo and alka ine; v the lanthanum carrier therefor, addiu g -nitric acidto the, resulting solution to precipitate said transuranic values and the thorium fluoride carrier for these transuranic w l e o e herw thfii e tlvt dec ea ed eono utrationtof are a th and a k eauh v lue and; n pe t ethe whose. ys etz-totet sq separat on 15 said; w n a tho nrflumide rom sai r r nd. alineear hmalues- I .18 t. process for th separationoftransumanip eleetedgfr .m the groupmnsisting of plutoniummndmep tuui m value 4fetype-=raret1earth alkaline value which -expraetiugaata atem erature, of o -ween .abou, ;70,and.,-1-Q0' 6; a-esolidioompositioniconf. taiuin'g' essentially said transuranic-values, v .a; thorium ,ox-. alatewarrien for said transuranic elements, and rare earth nd} alkaline earth: values and cerium (+3.: alence) rier th refor-smith: a saturated aqueous; solution of; a mix-a tmeaoi ammoniumifluoride. and ammoniummxalate, moving ,the. insoluble matter which consistsessentiallygf rare: earth and; alkaline; earth yaluesaandacerium therefor,- adding nitric acid-to thearesultingssolution, :to precipitateasaid transuranic values. and: oxalate. togeth'euu-withta greatly decreaseds concentration of earth and alkaline..- earth v alues, and: repeatingrthe above:v eyoletoeffeot further separationroftsaidtransuranic ualues' and-rthorium oxalate frqmasaidmaret eargthmamd; alkaline v eanthivalnes.

9. 'Alp rocess forlthetseparation-of tr ansurarnic valueslv I selected from the group consisting of: plutonium hep-A c tunium values. :4fatype rarerearth and al'lcalineeaflh} values, which comprises extracting at tempenatures of between about 70' and tCz-v-a-r solid =Oomposition containing essentially saidtransuranic values, a carrier for said transuranic values selected from the group consisting ofoxalates angl-gfluoride s of -thorium -I54 va lence), rare earth and alkaline earth andga carrier therefor seleoted-from the group consisting ct -lanthanum fluoride, cerium ,trifluoride strontium 'fl uoride, calcium fluoride, fluoride lanthanum 015alate cerous oxalate, oxalate, ealciumfoxalate selected from the group consisting of ammonium fluoride and ammonium oxalate, removing the insoluble matter which consists essentially of rare earth and alkaline earth values and carrier therefor, adding thereto sufficient mineral acid to produce a solution whose acidity ranges between 0.01 and about 10.0 N thereby resulting in the precipitation of said transur-anic values and the carrier for these transuranic values together wtih a greatly decreased concentration of rare earth and alkaline earth values, and repeating the above cycle to eflect further separation of said transuranic values and carrier therefor from said rare earth and alkaline earth values.

10. A process for the separation of transuranic values selected firom the group consisting of plutonium and neptunium values from 4f-type rare earth and alkaline earth values, which comprises extracting at temperatures of between about 70 and 100 C. a solid composition containing essentially said transuranic values, a carrier for said transuranic values selected firom the group consisting of oxalates and fluorides of thorium and uranium (+4 valence), and rare earth and alkaline earth values and a carrier therefor selected from the group consisting of lanthanum fluoride, cerium trifluoride, strontium fluoride, calcium fluoride, yttrium fluoride, lanthanum oxalate, cerous oxalate, strontium oxalate, oxalate and yttrium oxalate, with a solution of ammonium salt selected from the group consisting of ammonium fluoride and ammonium oxalate, removing the insoluble matter which consists essentially of rare earth and alkaline earth values and carrier therefor, adding thereto sufficient mineral acid to produce a solution whose acidity ranges between 0.1 and about 1.0 N, thereby resulting in the precipitation of said transuranic values and the carrier for these transuranic values together wtih a greatly decreased concentration of rare earth and alkaline earth values, and repeating the above cycle to elfect further separation t transuranic values and carrier therefor from said rare earth and alkaline earth values.

11. In a process for the separation of transuranic values selected from the group consisting of plutonium and neptunium values from 4f-type rare earth and alkaline earth fission product values, the steps which comprise contacting a solution containing said transu-ranic values in a valence state not greater than 4 and rare earth and alkaline earth fission values with a carrier for said fission products selected from the group consisting of lanthanum fluoride, cerium trifluoride, strontium fluoride, calcium fluoride, fluoride, lanthanum oxalate, cerous oxalate, strontium oxalate, calcium oxalate and yttrium oxalate and a carrier for said transuranic values selected from the group consisting of the oxalates and fluorides of thorium and uranium (+4 valence), recovering the precipitate thus obtained and extracting it with a selective solvent for said transuranic values and carrier therefor comprising a solution of an ammonium salt selected from the group consisting of fluoride and ammonium oxalate, and removing from the resulting solution the insoluble matter present therein which consists essentially of rare earth and alkaline earth values and carrier therefor.

=12. In a process for the separation of transuranic values selected from thegroup consisting of plutonium and neptunium values from uranium fission products the steps which comprise contacting the solution containing said transuranic values in a valence state not greater than 4 and said fission products with a carrier for said transuranic values selected from the group consisting of the oxalates and fluorides of thorium and uranium (+4 valence) and a lanthanum carrier for said fission products, recovering the precipitate thus obtained and extracting it with a selective solvent for said transuranic values and carrier therefor comprising a solution of an ammonium salt selected from the group consisting of ammonium fluoride and ammonium oxalate, and removing from the resulting solution the insoluble matter present therein which consists essentially of uranium fission products and carrier therefor.

13. In a process for the separation of transuranic values selected from the group consisting of plutonium and neptunium values from uranium fission products, the steps which comprise contacting a solution containing said trausuranic values in a valence state not greater than 4 and uranium fission products with a carrier for said transuranic values comprising thorium oxalate and a carrier for said fission products comprising cerous oxalate, re-

* covering the precipitate thus obtained and extracting it at a temperature of between about and about C. with an aqueous saturated solution of ammonium oxalate, and removing from the resulting solution the insoluble matter present therein which consists essentially of uranium fission products and cerous oxalate.

14. In a process for the separation of transuranic values selected from the group consisting of plutonium and neptunium values from uranium fission products, the steps which comprise contacting a solution containing said transuranic values a valence state not greater than 4 and uranium fission products with a carrier for said transuranic values comprising thorium fluoride and a carrier for said fission products comprising lanthanum fluoride, recovering the precipitate thus obtained and extracting it at a temperature of between about 80 and about 90 C. with an aqueous saturated solution of ammonium fluoride, and removing from the resulting solution the insoluble matter present therein which consists essentially of uranium fission products and lanthanum fluoride.

15. A process for the separation of transuranic values selected firom the group consisting of plutonium and neptunium values from 4f-type rare earth and alkaline earth values which comprises extracting at elevated temperatures a solid composition containing said transuranic values, a carrier for said transuranic values selected from the group consisting of the oxal'ates and fluorides of thorium and uranium (+4 valence), and an impurity of the group consisting of rare earth and alkaline earth values and a carrier therefor selected from the group consisting of lanthanum fluoride, cerium trifluoride, strontium fluoride, calcium fluoride, yttrium fluoride, lanthanum oxalate, cerous oxalate, strontium oxalate, calcium oxalate and yttrium oxalate with a solution of an ammonium salt selected from the group consisting of ammonium fluoride and ammonium oxalate.

16. A process for the separation of neptunium values from 4f-type rare earth and alkaline earth values which comprises extracting at elevated temperatures a solid composition containing said neptunium values, a carrier for said neptunium values selected from the group consisting of the oxalates and fluorides of thorium and uranium (+4 valence), an impurity of the group consisting of rare earth and alkaline earth values and a carrier therefor selected from the group consisting of lanthanum fluoride, cerium trifluoride, strontium fluoride, calcium fluoride, yttrium fluoride, lanthanum oxalate, cerous oxalate, strontium oxalate, calcium oxalate and yttrium oxalate with a solution of an ammonium salt selected from the group consisting of ammonium fluoride and ammonium oxalate, removing the insoluble matter which consists essentially of rare earth and alkaline earth values and carrier therefor, adding a mineral acid to the resulting solution to precipitate said neptunium values and the carrier therefor together with a greatly decreased concentration of rare earth and alkaline earth values, and repeating the above cycle to effect further separation of neptunium values and carrier therefor from said rare earth and alkaline earth values.

17. A process for the separation of plutonium values from 4f-type rare earth and alkaline earth values which comprises extracting at elevated temperatures a solid composition cont-aining said plutonium values, a carrier for said plutonium values selected from the group consisti mum fluo id a h n m. l tq; n Joxah e,

mintium ox a ca m: qxala nd umv o a with a. s u i 9 n amm ni m-Sa l t rom h @0 9 consi in o n um fluo d n ammnn u 6x 11??? -QQ Y Pg th ns lubl mm w i h onsis 1o a hf t si alka s a h Y H 7 No referenges cited.

Claims (1)

1. A PROCESS FOR THE SEPARATION OF TRANSURANIC VALUES SELECTED FROM THE GROUP CONSISTING OF PLUTONIUM AND NEPTUNIUM VALUES FROM 4F-TYPE RARE EARTH AND ALKALINE EARTH VALUES WHICH COMPRISES EXTRACTING AT ELEVATED TEMPERATURES A SOLID COMPOSITION CONTAINING SAID TRANSURANIC VALUES, A CARRIER FOR SAID TRANSURARANIC VALUES SELECTED FROM THE GROUP CONSISTING OF THE OXALATES AND FLUORIDES OF THORIUM AND URAMIUM (+4 VALANCE) AND AN IMPURITY OF THE GROUP CONSISTING OF RARE EARTH AND ALKALINE EARTH VALUES AND A CARRIER THEREFOR SELECTED FROM THE GROUP CONSISTING OF LATHANUM FLUORIDE, CERIUM TRIFLUORIDE, STRONTIUM FLUORIDE, CALCIUM FLORIDE, YTTRIUM FLUORIDE, LANTHANUM OXALATE, CEROUS OXALATE, STRONTIUM OXALATE, CALCIUM OXALATE AND YTTRIUM OXALATE, WITH A SOLUTION OF AN AMMONIUM SALT SELECTED FROM THE GROUP CONSISTING OF AMMONIUM FLUORIDE AND AMMONIUM OXALATE, REMOVING THE INSOLUBLE MATTER WHICH CONSISTS ESSENTIALLY OF RARE EARTH AND ALKALINE EARTH VALUES AND CARRIER THEREOF, ADING A MINERAL ACID TO THE RESULTING SOLUTION TO PRECIPITATE SAID TRANSURANIC VALUES AND THE CARRIER FOR THESE TRANSURANIC VALUES TOGETHER WITH A GREATLY DECREASED CONCENTRATION OF RARE EARTH AND ALKALINE EARTH VALUES, AND REPEATING THE ABOVE CYCLE TO EFFECT FURTHER SEPARATION OF THE TRANSURANIC VALUES AND CARRIER THEREFOR FROM SAID RARE EARTH AND ALKALINE EARTH VALUES.