QRNZ-3594

Contract fib. W-7405-eng-26

Reactor C h e m i s t r y Division

MOLTEN-SALT SOLVENTS FOR F'LUORIDE VOIATIWCTY PROCESSING

OF UWm-MATRIX NUCLEAR FUEL E=I;EsIENTS

R. E. Th.om B. J. S t u r m E. X, Guinn

AUGUST 1964

OAK RIDGE NAT3cONAL WlBORATOiiy Oak Ridge, Tennessee

operated by UNIQE\T CARBIDE COKPQRA!JXON

for the U.S. ATOMIC ENERCY COb5MISSION

$E532 hbstraet . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Choice of Constituent Fluorides as A333 Solvents . . . . . . 3

S w e y of Potent ia l Solvent Systems . . . . . . . . . . . . . 5

Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Wterials . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Results and Discussion . . . . . . . . . . . . . . . . . . . . . 9

d-UF3&klti.tlgPQbt . . . . . . . . . . . . . . . . . . . . . 9

System Bsed on LiF-KF . . . . . . . . . . . . . . . . . . . 9

The S y s t e m LfF.NaF.rn3 . . . . . . . . . . . . . . . . . . . 10 T ~ ~ ~ ' ~ s ~ w I N ~ + F - K F - A L F ~ e e . . t e 11.

The syStel3l p-zrF4-rn3 e . e e e . . 11

Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . 12

References . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

MOLTEN-SALT SOLVENTS FOR FLUOFXIIE VOLATIIJ ' IT FRQGESSING

O F ALUMINUM-MAmIX NUCLEAii FUEL 13L;EMETJTS

R. E. Thorn, B. IT. Sturm, E. H. Guinn

The resu l t s of a search f o r molten-salt solvents for i ise in. fluoride vo la t i l i t y processing of aluminum-matrix fuel elc- ments are presented. The solubi l i ty of alurminum fluoride i n various mixtures of fluorides was determined in order t o e s t i - mate the feas ib i l i ty and cost of processing methods. data were accumulated t o construct equilibrium phase diagrams of the solution systems, LiF-NaF-AlF3 Mi72 (where MF2 is CaF2, SrFz, or ZnF:!j, and ICF-ZrF4-KLF3. and revised phase diagrams were determined for the limi-bing binary systems of the alkali fluorides with &Fs by ime of a new visual method f o r determining the occurrence of liquidus transit ions. available i n c lass ica l methods of obtaining liquidus data. For example, it was observed f o r the first time t h a t irmnisei- ble l iquids are formed at high temperatures jn AlFg-based systems. however, higher than is feasible fo r adoption i n most current chernical technologies. O f the various materials evaluated as solvents for the vo la t i l i t y process, the greatest potential f a r application ms displayed by the KF-ZrF4-AlFg system. High solubi l i ty and good dissolution rates are afforded by the inexpensive solvent salt K2ZrF6. tures, approximately 6OO0C, the AlF3 capacity of the solvent is in excess of 25 mole $.

Sufficient;

LiF-KF'-AlF3, LfF-KNFG- New

This method provided several advantages not

The temperatures at which such l iquids form are,

A t operating tempera-

INTRODUCTION

Development of the fluoride vo la t i l i t y process i s sought as a useful and effective alternative t o conventional aqueous processing fo r recovery of uranium f r o m spent nuclear f'uels, fuel elements i n a suitable mol%en fluoride sol-vent by passage of €E gas

followed by fluorination of the result ing m e l t t o vo la t i l i ze uranium as

~ 6 . l

The process depends on dissolving

m e U F ~ ; is pwi f i ed by selective sorption on sol id Nap or other

2

fluorides Molten-salt fl?rorLde v d a t L l i t y processi;ng o f nixlear r'ueIs offers advantages n o t i3:VaK.able wl.t,h. other Chen6cR1. reprocessing mthods ;

(1) thc pmxess i s s iqAe,

a fluor%tmtion step instead of the mimy steps--dejacktirmg, acid d i s s ~ l i i -

t ion, precipi ta tbi l , fil.tra.tion> aqueous pl-oeedwes; ( 2 ) the ixanilun is recovered as 'm6, the fonn peqarea for iso-tope separation,' FVrd ( 3 ) rlisposal is inde 0% essen+uia1.7.y a l l fls--

2 requiring oldy a hydrofluorination step

etcc--'2hwacteristLc of the usual 3-5

ion prodIAt2tS as ~.~tc~*-i.nSolUble SO?.ldS, It is R!.SO OIE of the f e w m&A.ndS 7 that can be used for processing cer ta in ceran&c i%d.,S.

The process has been previously applied successfully t o zirconiim- 1,8,9 m'crix fuels. Cum-enl;ly, it i s consideyed far a l i~n inm-mt r ix Riels

because o f t he i r use i n nruiaerous reactors 'Ojl'- ami because o f the need ,ta-rticipa%ed. f o r processlang large quantities of these fuels e

b e of %he mast i a p o r t m t aspects of voiat i l2ty process development in adapting the process t o a part icular kind of f i e 1 element I s the selec- t i on of a. sanitahle rnol.tm-salJG sol:ient Into whi.ch to pass the HF gas dui:ing

dis;sol.ution. by Boles and good salubi l i ty f o r IuF3, but, because of expense anti toxicity, a i a l t e r - native solvent system i s preferred. They considered liP-ZrF4 soLlrents t o be of potential use, limited- for a crit ical . selection olf o@Amal solvents foy use in vo la t i l i t y processing. Accordingly, a more intensive search for solvents w a s i n i t i - ated using newer methds which perirmEt rapid acc~xmrlation of large numbers of liquid-solid t ransi t ion data,

f OlloFIing :

A preliminary sm?iey o f prospective AlF3 solvents reported

showed tba t a BeFa-LiF solvent provides moderately

The prsliminwy acta. obtained a t that t h e were too

Desirable characteristics of the solvent fo r tlar process inclujie the

1, Taw cost. 2, Liquidus teqer8twes below 60OoCc 3 .

4 . Low vapor pressure. 5. Low viseosity.

6 ,

Substantial salubi l i ty of AlF3 at 5OQ t o 600%.

Noncorrosive with respec-t; t o the IBJTOR-8 container.

3

I n reprocessing alumimm-mtrix fie1 elements, the temper&xwe must be kept below the melting point of aluminum (60Q°C)13 t o avoid forming l iquid metal, which is corrosive t o the container all-oy, IROR-8. cep t ib i l i ty of INOR-8 t o corrosion by l iquid aluminum Is offset by i t s excellent s t ructural properties at high temperatures and its resistLance t o corrosion by fluorine and IFF. It i s desirable t o prevent the maximum operating terrrperzzture from exceeding a 2.im.i-b of at leas t 5Q°C lower than the melting point 0% ahmhm.m; consequently, 600% has been tentatively chosen cis the m a h m temperature for the process. The economic feasibi l - i t y of the process i s highly dependent upon the cost of the solvent. Solvents in which the sa%urating concentrations f o r A E 3 are as low as 8 mole $ my be useful i f the solvent costs l e s s than 58 cents a pound. I@, however, higher-priced solvent cmponents %re required i n order t o obtain the tleslrable solvent characterist ics, the economic feas ib i l i ty of' the process may then require higher saturating concentrations of U 3 .

The sus-

Choice of Constituent Fluorides as A1F3 Solvents

The choicc of" possible solvent constituents can be rapidly narrowed t o one group: HE' and fluorine. Ca%ionic constituents should ei ther have only one va-

lence state as the fluoride? or both the lower fluoride, existing d w b g

dissolution, and. the higher fluoride, f o m d d w b g fluorination should be noncorrosive, possess suff ic ient ly low vapor pressure, and have sui t - able melting characterist ics fo r use i n the solvent.

cheap fluorides which. are stable 3-n the presence of gaseous

Previous t o the O R l K r.ro~-k: on the vo la t i l i t y process there was l i t t l e published information concerning the at tack of d-m metal. by molten fluorides, and none regarding the relationship of El? o r other dissolved 04ui&mt gases t o t h i s attack. a l k a l i m e t a l fluorides and with molten cryol i te t o form flree a l b l i metal and the appropriate fluosoalwnina <;?;e. l4 m e m e t d also reacts with molten K$lWf;, forming a Iph-Al a l loy and a potassium fluoroaliminale, Aluminutn m e t a l reacts with sol id CeF3 at 1000°C Lo fom cerium metal and MF3, with K221iF6, alI.mhW reacts t o form K Z ~ I ; , f'ree tit&m metal, mld ZUz

opaque phase believed t o be a eoqlex of TiF3.15 Published f ree-enera valueslG favor the formation of T I F ~ by the reaction:

It is known tha t aluminum reacts with molten

4

Most of the fluorides in thi,s group are suitable only as minor constitu- ents o f the solvent for the following reasons:

1. IibF, CsF, UF3, and ThFq are madeF&ely e .~~ens ive ,

5

2.

3.

4.

FeF2 and N i F 2 i n high concentrations m y present corrosion problems during f luorbat ion. MgF2, CaF2, SrF2, BaFr, and CeF3 have very hi& m e l t i - n g points (see Table 1). TiF4 in high concentrations my exert somewhat excessive vapor pressure.

These compounds were, therefore, considered not as major solvent consti t- uents but merely as possible additives for possibly depressing the liquidus of a promising solvent. AlFs, and ZrFq--were e v e n t h e principal consideration as solvent collrpo- nent s .

The remaining six compounds--Lip, NaF, KJ?, BeFz,

Survey of Potential Solvent Systems

Except for BeFz, which i s too viscous, none of the promising fluoride constituents individually has the necessary low m e l t i n g point (below 600aC 1 t o be used direct ly as the solvent (see Table 1) a

tures of these fluorides do, however, form adequately low melting eutectics (see "able 2).

l o w melting mixtures for possible use i n the process i s t h e W-AlF3 sys- tem; i ts capacity for additional N_F3 at the process temperature is, however, limited t o about 5 mole $, too l o w f o r process use.

A nmber of" binary mix-

zfhe only AlF3 binary system which provides sufficiently

In order t o find low-melting solvent; systems suitable for the proc- ess, phase relationships were stubicd i n the ternary systems formed by &issolving AlF3 i n a molten binary solvent;. more complex solvent systems because the s-Ludy sf polycomponent systems delineating the phase reactions occurring as ALF3 dissolves i n such sol-

vents is too invol-ved t o pernit adequate characterization i n a reasonable length of time. off-performance d i f f i cu l t i e s i n engineering tests by identification of crystall ized sol ids i s remote f o r multicmponent salt systems unless de- tailed investigation of the phase behavior has been made.

when a fourth component was considered, it was u s u a l P ~ only as 8 minor addition t o a promising ternary system, e.g. , A-E-AlF3, hcluded i n order to lower the liquidus temperatures enough t o meet process requirements. Ailthough the fluoride vo1atiliS;y process i s intended fo r reprocessing

L i t t l e concern w a s given t o

I n adtlition, the probability of diagnosing the cause o f

Accordingly,

7

melt may be observed as phase changes occur9 the apparatus i s also u s e r u l for obtaining interpretable thermal analysis &ta. the temperatwe recorder was periodically standardized against ELF m e l t - ing a t 84.8 k LOC.

To ensure accuracy,

22-24

The precision of temperature measurements obtainable i n routine use Occa- of Chromel-Alumel thermocouples i s generally believed t o be k5"C.

sional calibrations with pure salts have shown that the accuracy of thermal t ransi t ion t eqe ra tu res reported here i s within the S ° C precision limits.

Correspondingly, the accuracy of visual t ransi t ion data reported here i s within S O C .

A similar visual procedwe called "visual p o l y t h e m l method'f has been 11se.d by Russian but t he i r procedure seems infer ior t o that used here i n tha t it apparently does not permit (1) agLl;a-bion of the observed m e l t , (2) addition of salt during the run -to alter the com- position, or ( 3 ) use of vacuum t o control the atmosphere.

A sharp increase i n viscosity i s of'ten displayed by molten salts as they cool to tenrperatures approaching the I-iquidus. 2n most of the systems discussed i n this r q o r t sad was useR11 In signal- ing the onset of crystall ization. been observed also by Velyukov and Sipriya26 for J!Ja$OI?6 a d LiflFg md.

by E l l i s 2 ? for Z n C l 2 .

phase-tmasition temperatures was also noted. e l ec t r i ca l conductance using an ohmneter (Model 630, Trlplet t n e c t r i c a l In sLmen t Company, Bluffton, Ohio) indicated that it m y S ~ S O provide a

pracedwe useful fo r study- AlF3 systems.

This effect w a s noted

Such a sharp chlange i n v5scosity has

A sharp change i n the e lec t r ica l conductance at Preliminary measurement of

Purity of the fluorides used in the phase studies was very important.

The molten-salt systems Were studied primarily by a visual procedure which, in determination of a 1.iquidus temperature, depended on the appearance of precipitate, orten in such a form t h a t it clouded the melt. Accordingly, any impurity which clouded the melt interfered with the study. Because they reacted to fom very sparingly soluble phases, hydroxides and water

8

9

RESULTS AND DTSWSSION

In the search fo r high-capacity solvent systems for use i n the f luo- ride vo la t i l i t y process, equilibrium solubi l i ty data f o r aluminum fluoride in seven fluoride systems WEE obtained.

MF-KF-AlF'3, K$lF6-LiF-CaF2, Km6-LiF-SrF2, K f l F 6 - U F - r n 2 , LiF-NaF- MF3, NaF-KF-fUFs, and KF-ZrF4-A.lF3. the data obtained in these examinations show that only one of these systems, Q-ZrF4-AlF3, can be expected to have pract ical application as a solvent. New data were obtained f o r the limiting bfnary systems LiF-ALF3, ?&3,F'-AJ_F3,

KF-AlF3, and KF-%F4. shown i n Mgs. 8 t o 11. Experimental data for the systems reported here were collected simultaneously for several systems, thus mklng it possible t o cu r t a i l the e f for t s on any ane system as the development i n another system showed promise.

The systems examined included

The phase diagrams constructed from

Hew phase diagrams of each of these systems are

m3 Melting Point

Previously report& experhental values for the melting point of AlF3 range f r a n 986= to 1040°C.28 All of our visual observation data

indicate that these values are l o w and tbt the nelting poi& is higher than the reported sublimEttion temperature, 1270°C,29 though not as high (1920OC) as was regarded by Stemenberg and Vogel. x, Because hi@ liquidus temperatures and vapor pressures prevented visual study of mixtures con- taining over 56 mole $ AZF3, too l i t t l e data were. obtained t o permit a good extrapolation of its m e l t i n g point. tu re t o equilibrium melting point at l a t m i s close t o that for CrF3, 144X0C.

Since AI33 2s of similar stmc- and of comparable s i ze r e l a t i ~ n s h i p , ~ ~ we surmise that i-bs

Systems Based on LiF-KF

Mixtures of %he l ightest alkazi fluorides, LiF, NaF, and KF, m e not so low melting as those obtainable with RbF or CsF; the cost of these l a t t e r t w a materials, however, precludes the i r economic u6e i n process development. The binary mixture of the cheaper fluorides which affords the lowest-melting

The System NaF-KF-AlFa

Preliminary investigation o f the system P s j F - K F - A l F ~ made by &.ston e t indicated tha-t Etluminm fluoride solubi l i ty was negligible i n NaF-KF m i x t u r e s except at temperatures above the NaF-E eutectic. inference was corroborated by addirtional experixnents conducted as part

of the present investigation,

-I

This

Binary systems of the a lka l i fluorides d t h 7zF4 afford bow-melting solvent mi,xt;ures for the heavy-metal fluorides W g and 1W4 and e m be

eqec ted t o provide useful solvents for AlF3 as well. would be preferred because of the high cost of Z r F 4 and because of the vo la t i l i t y of ZrF4-rich l iquids at high terqpemtwes. Nevertheless, the liquidus temperatures at Concentrations of 35 ts 45 mole 5 7irF4, i n the JSF-ZsF4 system and the avai labi l i ty o f K22rF6 8 s an inexpensive reagent suggested the use o f the reagent i n the prelitnimwy evaluation of the

alzrmlnum solvent t igat ion are shown i n Table 9.

in Fig. 7. Grystallization reactions withfa the s y s t a KF-ZrF4-AU3 have

been characterized in detail. except for those hva4_ving . U s and ZrFg:.

Both of these components m e high melting and volati le. t ions w e extremely rl;if'fieul-t t o examine at high t eqe ra tu res because of

Other solvents

The experimental data obtained i n this inves- The phase di-m of the system is shown

Their phase reac-

t h i s vo la t i l i t y and t h e i r Low heat of fusion, which preclude most c

methocis for obtaining phase data, Their crystal l izat ion reactions In the ternary Hlixtures suggest that the only interaction occurring between them at hi& temperatures is the formation of a evtcctic. we have omitted investigation of the 1Mth.g bin= system AlF3-ZrF4.

600°C, the rmximum acceptable temperature for the process, a solvent, KF- ZrF4 (63-37 mole Liquidus temperatures i n the binary system KF'-ZrF4 exclude the m e of solvents richer Fn KF. It can be seen fYum the phase diagram of the system KF-7zFq- ALIi"3 (Pig. 71, canstruc%ed i n this stud;y, that by a single addition of KF arter p a r t i a l dissolution of the me1 element the solub,ility of A D 3 i s increased f r a m LS t o 26 mole $.

For these reasons, A t

was found t o have 15 mole 9 AlF3 capacity.

13

13

-83 e 36

848.0"

545, oa --L28* 7"

9%. CP L263.0"

-90.3"

-93.8

857 rn 0"

I.4l8.0"

1406.0"

19.5

lAo4. of -150.0

930.0

950 OQ

1300. 0g

-1200.0

872.0 -

19.46

1681,O

1.15 9 0

-99,9

2704.0

2260.0

1273.05

-95,P

-84.6

1502.0

2500 0

283 * 3-

-14u0.0

4 c 3

150. c j

!!800. 0

-1300, Gg

-1725 * 0

16'77 a 0

1500* 0

64, T

138.8

207.5

269.5

151.3 129.0

250.8

306 I) 0

360.0

127.4

350.0

350.0

254,o

172,o 250.0

327.0

180.0

223. 0

158.0

219.0 2.47 0

174.0

lA7.r)

118.0

3-64- 0

239.0

271,O

-5.0

-%,6

7% Qa

1400.0

910. 0g

78.9 17.5

4-35 0

1110.0

290.0

a, 3

-37.8 682 + O2

1290.0

1460. Oa

95. I.

8 - 2

18.8

34.4

645.0

58

-45.9

1&08.0

2410.0

- 900. og 233.3 35.0

1748.0

850. OQ

376.0

1-42. ‘7 38.9

1.251 0

2260.0

229.2

17.0

47.6

47.3

647 s 0

189.0

221*8 1-25 L 7

276 7

380.0

424. O

320,o

383.0

2?9* 0

105.0 44.3

153,3 234.0

147.0 237.0

200.0

286,5

292.0

124.5

274-0

403.0

398.0

413-0

339,O

258.0

179.0

72-0

84.. 0

83,O

15

'Bible 1. (continued

T3.F 327.0

TlF3

PbF2 824. oc BiF3 850.0

BiF5 151,4

655.0

230.0

60.0

159. c)

14G.6

2ocs.o

ThF4 I lOO. 0 2680.0 454.0

m4 10% " 0 1417 0 421.5

a La;ndoL.t-B6rnsLein, Zahlenwerte una Funk-tionen, V o l . 2, Eigenschgfien der Materie i n Ihren flggregatzustanden, Part 4 , %alorische Zuslmdsgr6ssen," Springer, Berl-Jur, 6th ed.., 1361.

bL. Brewer, "The Fusfon and Vapx5zaLion D;zta of the Ibl ides ," Paper 7'? p 193-275 in "he Chemistry and Pil[etallurpy of Miscellaneous Materials: Thermodynamics, ea. by 14. L, Q u i l l , McGraw-Hil l , New Yorlr., 1950; Metallurgical hbora tory Report cc-3455 ( 1944 1.

c A. Classner, The Thermochemical. Fxoperties cf the Oxides, Fluorides, ana Chlorides t o 25000K, nrsL-5"75O (1957).

dSublimation point e B. J,

8'7 (1963). Sturm and C. W. Sher ihn , Inorg. Syntheses, '7,

.I -

fB. J. S t m , Inorg. Chem. I 1, 665 (1962).

%meported melting points based on vork at 0RT\TL, sometimes

..,.

only an approximate val.ue based on preliminary experinen-ts.

16

7% 683

68-5

5'70

7'70

63%

432

71.0

355

3G 5 34c

323 330

50'f

500

430f

720

936

Table 3. LiF-KF-AlF3 Liquid-Solid Transition Data

Crystallization Second

(mermal Anapjsis)

Solidus The,~l T qElcctrieai erature ( O C )

Analysis Conductivity V i sua1 Them1 Electrical Temperature (oc) Composition (mole $1

LiF KF mF3 Obsemation Analysis Conductivity

100.0

88.5

86.0

80.0

75.2

75.0

71.6

66.7

63.2

62.5

60.9

60.0

58.8

57.2

57.1

55.6

52.7

50.0

11.5

14.0

20.0

24.8

25.0

28.4

33.3

36.3

37.5

39.1

40.0

41.2

42.8

42.9

44* 4

47.3

50.0

75.0 25.0

848

779

725

765.5

784.5

772

'775

735

745

728

730.5

770

747

812

786

802

86G

1035

996

848

735

766

785

771 787 775

734 738

772

770 775

747

E112 824

802

935

845

711

771

699

708 711

706

710

709

995

Table 3. (continued)

5.9 11.1

20.0 27.3 33.3 41.7 45.5 50.0 55.6 62.5 64.1 71.4 83.4 67.5 61.4 56.25

57.2 54.6 50.0 42.8 70.6 66.7 60.0 54.5 50.0 43.7 49.9 37.5 33.3 28. 1

26.9 21.5 12.5 7.5

13.6 18.75

42.8 45.4

50.0 57.2 23.5 22.2 20. G

18.2 16.7 14.6 13.5 12.5 11.1

9.4 9.0 r7 -. t .i

4.1 25.0 25.C 25.0

570 569 642 710 971 951 917 889

865 839.5 821 800 769 727 722.5 749.5 791 731.5 690 649.5

722

730

559 565 575

714

718

722 718

647

649

Table 3 . (continued 1

Solidus Temperature (OC) Second Crystallization Thermal Electrical ~. .. _I "hermil Electrical

Liquidus Temperatme ( OC Composition (mole $1 Visual

- / O 7 1 *-,., --'? Conductivity 7- h - I T - 3 1 * - xempera-cure i

m r a i y D I t (Thermal- h a l y s i s ) Observation Analysis Conductivity J l F Lt!

50.0

45.0

4-9.9

37*5

30.0

25.0

33.3

25.0

20.0

16.7

15.0

14.3

13.0

12.0

15.4

21.4

26.7

25,o

25.0

30.0

34.1

3'9.5

45.0

50.0

16.7

25,0

30.0 33.3

100.0

4 .0

38,o

34-8

32.0

30.8

28.6

26. '9 25.0

25.0

25.0

25.0

25.0

25.0

25.0

50.0

50.0

50.0

50.0

45.0

47.7

52,2

56.0

53.8

50.0 46.6

50.0

696

727

74-9

767

802 843

976

893

858

824

854

593

623

970

1098

1043

813

690 858

749

462

652

589

622

805 685

645

645

6-45

778 779

852

567

587 565 593 564.

592 563

597 561

605

608 540

20

Table 4. Invariaril; Equilibria in the S y s t e m LiF-FLF-AlF3

50.0 50.0

93-0 7.0

56,O 44* 0

50.4 49.6

85.5 1-4 . 5

64.0 36,O

53-0 47.0

56.0 19.0 25.0

33.0 42.0 25-0

28.1 62.5 9.4

6.0 48.0 46.0

45.5 53.0 I--5

4.92

850

560

575

711.

710

890

648

'778.5

7 2 Z 5

500

490

Eutectic

h i t e c t i c

Eutectic

Peritcctiie

hbLec-bic

Eutectic

Pe r i t ec t i c ( ? )

mtect ica

peritectica

Eutectic

Eutectic

Eutectic

5

a I n subsystem Kfi lF6-Zi f l F g .

subsystem KdlFg-L iF .

21

VisualLy Thermal analysis Data

Liquidus Liquidus lization !Ik?q, Solidus Second Crystal- Cw?lposltion ~ m l e $) Detenninf?d

K a F 6 J3.F CaF2

100.0

80.0

66.7

57.2

50.0

40.0

33.3

28.6 25.0

20.0

18.2

13.3

ll.7 8.7

8.0

7.6

18.9

16.3

14.3

12.7

10,8

9.3

24.1

22.6

21.2

20.0

20.0

33.3

42.8

50.0

40.0

36.4

53.3

58.9

69.6

64.0

61.6

54,l

60.5 65,3

49-1

73.8

77.4

69.0

64.5

GO. 6

57.2

20.0 33.3

42.8

50.0

4-0.0

33.3

28.6

25.0

40- 0

45.4

33.3

29.4

21.7

28.0

30-8

27.0

23,2

20.4

18.2

15.4

13.3

6.9

12.9

18.2

22.8

781

848 870

993.5 992 992

971.5 969

955 950 937

973 944

sou. 945

959.5

908 682

869.5 682

839.5

961

9%. 5

912

876 850 697 688

695 688

695

827,5 715 680

799.5

779 759 675 761

730.5 714 680

719 710 680

831 720

830.5 714 680

826

ti25 712 675

905

875

858

22

Table 6. K$I.U's-SrFr: I jquid-Sol id Tti.ansit3.m Data

7.7

14.3

20,o

25.0

65.7

50.0

a. 0

33.3

50.0

60.0

66.7

75.0

80.0

83 * .3

76.9

71.4

66. '7

62.5

1.6.7

25.0

30.0

33.3

50.0

40.0

33.3

25.0

20.0

15.7

15.4

14.3

13.3

12.5

16.7

25.0

30.0

33.3

1048 7 57

970 967

313

832

774

780 778 767

739 703 632

776 '705 693

829

853 848 703 695

965.5 954

939 930 686

930 918 690

335 903 698

23

Table 7 . K$YLF6-LiF-7ZnF2 Liquid-Solid Transition &ta

Visuizlly Them1 Ana1ys.i.s Data

Liquidus Liquidus lization Temp. Solidus

Cmposition (mole $1 K-6 LiF %2'2

Determined Second Crystzl-

12.2 87.8 722.5 722 722

21.8 84.0 4.2 720 720 655

11.3 80.6 8.1 713 712 663

10.9 77.5 11.6 705 705 668

10.4 74.6 14.9 701 701 670

9.7 69.4 20.8 690 6119 670

9.0 -65.0 26.0 675 6'75 668

8.5 61.0 30.5 669 668

8.0 57.5 34*5 673

7.5 54.4 38.1 666

7.0 50.0 43.0 6 67

563

562

562

24

8.3

15.4

21.*4

26,7

35.3

11.1

20" 0

27.3

33 ,3

75.0

55.6

50.0

47.7

45.4

41.7

38.4-

35.8

33.3

29.4

66 7

60.0

54.5

50.0

25.0

44.4

50.0

52.3

54.6

50. 0

4 . 2

42.8

40.0

35.3

22,2

20,O

1.8.2

16.7

1007

729

$53

1030

1083

858

729

693

66%

636

954 '185

939 744

882 692

849 722

674

660

645

638

627

1005

692

599

6W

601

603

692

594

694

25

W o l e 9. The System KF-AZF3-ZrF4

Composition (mole $1 Visually ~ h e m 1 h a l y s i s Data" Determined Second Crystal- Llquidus Liquidus l i za t ion Temp. Solidus KF U F 3 Z r F 4

75.0 75.0

50.0

45.4

40.0

33.3 25.0

50.0

44.4

4Q. 0

33.3

66.7

70.0

72.7 72.7

76.9

71.4 66.7

62.5

62.5

53.6

46" 9

41.7

37.5

34.1.

50.0

44*4

4.0.0

33.3

22.2 10.0

9.1 9.1

7.7 14.3

13.3

12.5

20.8

17.9

15.6

13.9

12.5 11.4

25.0 25.0

50.0

54.6

60.0

66.7

75.0

ll. 1

20.0

33.3

U.1 20.0

18.2 18.2

15,4

14.3

20.0

25.0

16.7

28.6 37.5

44.4

50.0

54* 5

920 3- 4 920 935.5 +- 4 932

6 0 4 2 4 6100

580 -t f 580

573 5 4

650 -t 4

760 -t- 4

648 k 3

975 3

1030 k 4

x o 3 0 * 4

890 2 3

920 k 3 915

938 5 3 934 942 5 3 934

932 k 3

920 932

a0

440

5.40

520 408 585,442 410

499 42%

934 rt 3

847 3- 3 482

570 5 4

649 +. 4

721 k. 4

505 485

743 4 4 743

821 5 4 81 8 582 438

869 f 5 858 575 428

>loo0 2 5

%recision limits on thermal transition data are approxlmately 5 5 O .

bMetastable transition.

26

27

UNGLASSI FlED ORNL-LR-DWG 20293

-0VE PORT RUBBER GI

Fig* 1. Schematic, D r a w i n g of Appara-tus for V i s u a l Studies.

28

J

Fig. 2. Visual Study Apparatus with Accessories.

UNCLASSIFIED PHOTO 6459%

Fig. 3 . Apparatus f o r Vacuum Sublimation and Distillation.

30

0

0

0

u)

d

0 0

Oi

I

---+---

I

0

0

m

31

A1 F3 -- 1 4 9 0

/\

E-490' \ - S E E INSi-T

LIF 8/19

32

UNCILASSIFIED ORN L- DWG 64-4 537

4 I F3

ii F

33

IJNCILASSIFIEU OkOil - 0 W G 63-4685

Fig. 7 . Tfle System KF-ZrF4-ALF3.

1,

2,

3 ,

4

5.

6.

7.

8.

9.

10.

5.1. I

12 c

13.

14.

15.

16.

Chem. Tec

R. P. Milford, Process I)Cvelopx?nt in the ORLi', Fluoride Volati l i ty ProgTaJfi --. October1 962 t o Sep&?nher 1363, ORW, 'i'M-717 ( O C I . 25, 1965)

R. E. Blanco am3 C , D. Watson, "I-Ieat-Znd Processes f o r Solid Fliels," C h a p - 3 , p. 23-106 in Reactoi- I-ln~T'nsok, ___I ed. by S. M. Stollerc and 3. E. Hichards, Vol. 11, Intcrseience, New Yqrk, 1961.

C. 14. S13asky, "Preparation of Fuels f o r l3rocesshg," L-ap. 3 , p. 75-

-_._.I @hem. .. Y'ech. Div. Ann, Progr. .- Rcr~$. June 30, 1962, ONTi--331/t, p. 39.

"Resjcarch and Ptevelopmeric on Nonaqueous Proceu!; - Volat i l i ty Proc - esses,

11. F. Sawyer and P. T,owenstein, "Fuel-Element Fabi-ica-ti on Faci l i t ies , ' I

Appendix B, p. 673-700 ilra Nuclear Reactor Fuel Elements . ..._- - Metallurgy and WbricaS,ig$, ed. by A . 3 . Kauflnm, Tnterscience, New York, 1962 ~ ~ $ - " e s p ) e c i a l l y Table U- 2, p. 690-5).

Reactor Fuel Proccssizig, 6 , 19 (1 96.3). m _-

P. S. Martin and G. L. X l e s , C3emical Processing _I of Duclear Fuels, p. 22-3, AcadernLc Fress, Ncw York, 1958.

A. Glassner, The 'Ihermochemieal -..-*+ Pro- e r t ies -.--.I- o f the Oxides, Fluorides, -...-.- and C?llori.des to 2500°K, APlL-~i50 il 3n.

35

1.7 *

18.

19.

20.

21 "

22 a

23 .-

24 D

25.

26 *

27,

28 c

29,

30.

31

32.

WRP Quas., Psog . Rept, Jan. 31, 1.959, 03NL-2684, p.

3. J. S t w n , "Prepxra.tfun of Inorganic Fluorides,'s p. 1.86-7 in Reactor Cllem, Div. .h. P r o p . Rept. Jan. 313 1560, 0RNl;-2931.

PSI?? Prop. Rept. March I to Aug. 31, 1961, QRm-3215, p. 122.

R. Ze Thorn2 e t a l "Molten Fl-uorlde Mixtures as Possible Fuel Reproe- - - 0 9 essing Sol.vents, p. 257-9 i n Reactoz- Chem. Div, Aum. Pro@* Rest. Jan. 31, 1963 ORN7;-3417.

-0

T. 13, Dauglas end. J. L. De~er, 3. Am. C h ~ m . Soc. 76 4826-9 (1954)- -9

p. J.W.

A, B. D e n w i t h , "Lfthizrm Fluoride " p T'reatisc on Tnosganic and Tlieorctical Ckmistry, Vox. XI, Suppl. 11, ikngmms, Green, Ifindon, 1961,

174-7 in Nellor '6 Coqrehensive

R, B. Ellis, ''Surface T'ension of Fused Zinc Chlor%fi,e9'' Southeast Re- gional Am. Chem. Society Meeting, NOT. 14-16, 1963, Program ana Abstracts, p. 87.

€1. 3. Emeleus, "Non.rolatility Inorganic Fluorides," pp. 10 and 4.0 in Fluorine Chemistry, Val. Ib ed, by S. II. STmons, AcmiernLc Press, New York, 1950,

L. Brewer, ''The Fusion and Vaporization Data of the F l ides ," Paper 7, p. 193-275 in The ~ d s % q y and Metallurgy of EIiscel.lmeous Materials - Therm0 New York, 1950;

E, K. Stemenberg and R. (1. Vogel, "Fluoride and Other Halide Vola- tilfty Processes," Chap. 6, p. 250-312 i n Reactor Fhndbook, Vola IT, Fuel Reprocessing, ecL by S. 14. Stoller and R. I3. Richards, Interscience, New York, 1.961.

A. F1 Wells, Structural Lnsrgstnjc Chemistry, 3rd ed., Uxfard, E&@and,

I

OIUK - 3 594 UC-4 - Chemistry

TTD-4500 (3lst ed, 1

1. Biology Library 2-4 . Central. Research Library 5. Reactor Division Library

6-7. OENL - Y - I 2 Technical Library Document Reference Sect Ton

8-62. Laboratory Hecords Depa,rtment 63. Laboratory Record-s, ORNL 13. C . 65. J. E. Bigelow 66. C. M. Blood 67. G. E. Boyd 68. M. A. Bredig 69. J. C. Bresee 70. W. H. Carr 71-. W. L. Carter 72. G. I. Gathers 73 i;. W. Cla.rk 74. W. E. Clark 75 . F. L. C i ~ l l e r 76. 13. A. FrieISnan 77. W . R. G r i n i e s

C. J'. Barton

7s-87. E. K. Guinn 8g. C. E. Giithrie 89. c. A. Horton 90. E. W. Horton 91. C . E. Larson 92. H. F. E4cDuffi.c 93. H. G. MacPtiez'son 94. Gleb Manant ov 95. R. P. Milforla 96. M. Je Skinner 97. G. P. Smith

98-107. I3. J. StuXTn 108. J. A. Swai*tout

1.19. A. M. Weinberg 3-20. J. P. Young 121. L. Brewer (consultant) 122. F. Daniels (consultant;) 123. R. W. Dayton (consultant) 124* E. A. Mason (consuLtmt)

109-118. R. E. ThoIIla

125. Research and Development Division, AEC, OR0 126-717. Given dis t r ibut ion as shown i n TID-4500 (31st ec2. ) under

Chemistry category (75 copies - OTS)