B.A.R.C.-607

ii

GOVERNMENT OF INDIAATOMIC ENERGY COMMISSION

FURTHER STUDIES ON THE PILOT PLANTPRODUCTION OF REACTOR GRADE

ZIRCONIUM SPONGE

*>yChintamani, P. L. Vijay, R. B. Subramanyam

and C. V. SundaramMetallurgy Division

BHABHA ATOMIC RESEARCH CENTRE

BOMBAY, INDIA

- 1972

B.A.R.C.-607

0

GOVERNMENT OF INDIAATOMIC ENERGY COMMISSION

FURTHER STUDIES ON THS PILOT PLANTPRODUCTION OF REACTOR GRADE

ZIRCONIUM SPONGE

by

Chintamani, P. I*. Vijay,. R. B. Subramanyamand C. V. SundaramMetallurgy Division

BHABHA ATOMIC RESEARCH CENTREBOMBAY, INDIA

1972

ABSTRACT

The report presents the revol ts of further invest igat ionsout i n the Zirconium £Llot Plant of the Metallurgy Division,

Atosdc Research Centre, Irambay, on the production of nuclear-gx*n«» d u c t i l e sLrconiufi sponge, i n 15 kilogrem batches*

la * specially designed stainless steel retort - withe foy seaftxoUed 3**sone heating sod continuous sensing

of apstHgB pressure with an argon purge tube - which could be operatedeitba? a s « closed system under poaLtire pressure or as a flow systeauade? sxgcm gas flow, the reduction of anhydrous zirconium tetraehlorideboth with magnesium alone and with magnesium and sodium has beensxanLneda The reduction product was subjected to a pyrc-vaouumtroatswtit to separate the by-product MgClj and excess magnesium, andi i o l a t e pure sLrcoaium sponge metal, which was crushed, graded aodevalutteA*

Ductile, zirooniua sponge meeticg nuclear grade specif icationswio obtained both i n s traight magnesium and in bi-jnetal reductions,with superior purity and bet ter orushabil ity i n the l a t t e r c a s e .7Jhe operatLoao i n partioular established the su i tab i l i ty of thereduotioa retort design and the process conditions for largeroperatLan**

FURTHER STUDIES ON THE PILOT PLANT PRODUCTION

OF EEACTOR GRADE ZIRCONIUM SPONGE

Chintamani*, P.L. Vijay, R.B. Subramanyara*and C.V. Sundaram

1« IHTaODUCTION

1»1 Investigations oarried out in the Metallurgy Division!

fib&bha AtoH&o Research Centre, Troabay, on the production of reactor

SKlrconiuia sponge in 2 kg batches - starting with pure zirconium

cxLde wad adopting the c h l o r i d e route - have been described i n

reports* ' ^ • In the context of s e t t i n g up of a large s c a l e produc-

t i o n plant f o r zirconium sponge from zirconium oxide (60 tonnes per

year) a t t h e Nuclear Fuel Complex, Hyderabad , i t was considered

necessary t o exan&ne -tiie ox ide to metal f low sheet on an intermediate

s o a l e of adequate s i z e , wi th the object of ( i ) generating meaningful

engineering data relevant to the design of fu l l - sca le plant) ( i i )

test ing of various process control instrumentatLon and equipment

essent ia l for the smooth sad safe operation of a large scale plant

and ( i l l ) creating a nucleus of trained staff to be later entrusted

tilth the task of erection and oojmiseioning of the faU-s«al« plant-

1 «2 Keeping i n view that the batch s i z e s in the zirconium and

hafnium sect ions of the proposed tonnage plant would be around 250 kg

and 100 kg respectively, a batch s ize of 15 kg was chosen for the

intermediate scale operations* The results of these investigations

are presented i n th i s report*

1*3 The flow sheet adopted for conversion of oxLde to the

reactor grade sponge was as follows t

n) Preparation of coked briquettes from ground oxide ana

carbon mixture*

* now with Nuclear Fuel Complex, Hyderabad*

- 2 -

fc) Ohloxlnatlon of briquettes to produce anhydrousBireonium tetracblorlde.

o) Pireifieation of raw chloride.

d) Magnesium or fai-metal (magnesium and eodlue) reduotLoaof pure zirconium chloride*

e) fyxo vacuum separation of chloride/chlorides anaexcess reducing agents*

f) Crushing, grading and evaluation of sponge*

1 *4 Itee zirconium tetrachloride required for the reduction

•tap was produced from hafnium-free zirconium oxide received fromthe pilot plant operations of the Chemical Engineering Mvieioo,Bhabha Atomic Research Centre^ • Deta i l s of equipment used andthe prooess employed for t h e steps ( a ) , (b) & (e) mentioned abovehave already been reported i n the ear l i er publications* Duringt h i s period i n order ta further augment • the supply of raw zirconiumtetraohloride a 200 nm di a ver t i ca l shaft eULCa brick l ined chlorina-tor wi th se l f - res i s tance heating of briquettes was a l so eomolssicnefland put i n t o operation*

2 . MAGNESIUM SEDUCTION OF ZIRCONIUM TBTRACHUORIDE

g#1 Bquigaest for Seduction

Equipment used for the controlled reduction of pure zlrconluatetraohlozlde vapour with molten magnesium (r ig .1 ) oomprised of toofol lowing major componentst-

A . Sta inless s t e e l Cylindrical BetortThis was fabricated from AISI 310 5 quality s t a i n l e s sa t s e l (l ,I>. 460 am. height 1425 ma, and waU tbiotoesa 6 as )with a demountable flanged top closure having a water cooledneoprene '0 ' r ing gasket to ensure leak-ttghtness againstia teroa l vaoium/pressure. The welded bottom closure of theretort was provided with a flanged nossle opening of 50 s a

nominal sLse at the oentre to serve as a tap-port for anyexperiments involving tapping of magnesium chloride in themolten state* The retort was also equipped with a vertioalside pipe of 25 mm nominal else welded close to the basefor possible experiments xn a flow system.

!Ehe top closure of -tiie retort carried welded nozzles forpneumatically operated angle type bleeder and argonadmittance cum evacuation valves, a manual bleeder valve,a 6 mm nominal dia argon purge l ine, a control coolingco i l and a sodium in le t line*

The enarge assembly inside "the retort consisted cf an AISI430 type stainless steel crucible (380 mm I.D. and 380 ranfcigh),'a baffle separator (205 mm high) of AISI 430 type?

• and a chloride can (380 rim I.D. and 560 mm high) fabricatedfrom inccnel.

B» Reduction Furnace -The reduction retort -mentioned above was heated by means ofa 3-zone nichrome would pit type electric resistance furnaceof 55 KW rating having independent on-off temperature controlsystems for each zone. Hie top, saddle and bottom zoneratings were 5, 25, and 25 KW respectively. In addition tothe afaove, a 5 KW heater was also provided at the base ofthe retort for uniform and rapid heating of the bottom sonsduring operation*

The furnace was supported across a steel mezzanine floor onwelded lugs at approximately half i t s height. An overheadtwo tonne capacity 2.0.T. erene facilitated loading andunloading of charge assemblies.

0* Xfcesoure Control Panel

In addition to the temperature control panel meant for thefurnaoe, a pressure control panel comprising (l) mecuallycontrolled solenoid valves for actuating the two,pneumaticvalves, ( i i ) a purge meter with a differential pressureregulator to faci l i tate purging the pressure recorder line

- 4 -

t t a constant rate of argon sad ( i i i ) a pressure recorderto record tfaa system pressure continuously during reduction*mis designed, fabricated, end assembled for controllingthe system pressure during operation.

2*2 Assembly for Reduction

ID a typical closed-system straight-magnesiua reduction run,ajrouad 11.4 kg of freshly pickled magnesium (10$ excess over theoreti-cal requirement based on chloride charged) was loaded into the reduc-tion crucible and lowered into the bottom zone of the retort. The

chloride can was placed on top of the crucible with 1toe bafflein between. Around 50 kg of pure zirconium tetrachloride

unloaded (from polyethylene bags) into the chloride can.She retort top closure was quickly bolted down ensuring that theneopren* >0> ring was in position.followed by a l l pneumatic and•leotrioal connections to the various valves and line heaters*

2»3 Operating Sequence

Reduction of zirconium tetrachloride with liquid magnesium

was oarrled out-, as follows;-

( i ) The system was evacuated at room temperature with the helpOf a rotary mechanical high vacuum pump and back-filled .with argon* This operation w«is repeated twice to ensurecomplete removal of atmospheric air and occluded gases*

( i i ) Ihe chloride was 'pre-conditioned1 prior to reduction inorder to remove all volatile impurities which can causepressure build-ups during reduction and also lead toproduct contamination. For ,this conditioning programme,the retort was gradually heated upto 300 °C under a slightpositive pressure of argon with periodic bleeding toremove a l l volatiles • The system was again evacuated atthis temperature and soaked in dyaaado vacuum for 30 minutes*Argon was then admitted into the system and the zonetemperatures gradually raised upto 45O°C nLth periodic

- 5 -

bl«ediag to «n»jyf further removal of volatila impuritiesAnd to maintain the system pressure always around1 to 2 palg.

( i l l ) Oja completion of -file chlorLde conditioning cycle, thereduction zone temperature was raised to 850°C to rapidlymelt 1&e magneaLuiB and Initiate reduction, ftortng thisheating period, the middle zone power was switched off toavoid premature sublimation of the chloride prior to reduc-tion. The radiati.cn heating from the bottom zone wasadequate to vaporise zirconium tetraohloride at thebeginning stages. She top zone as well as all the processlines/valves were maintained at a temperature of around45O°C to avoid chloride condensation.

2*4 giascesB Control

A purge of around 165 ce/mLn of argon was continuouslyottered into the system to avoid choking of the pressure sensing line*lor approximately one hour from the point of switching-on full power.•the system pressure-was cent rolled by periodic bleeding of vapoursuntil the appearance of dense white fumes* Subsequent to this ,pressure control was mainly achieved with the help of air cooling onthe cooling coil* Planned bleeds were, however, taken at intervalsOf one hour in order to eliminate impurities aid corrosion productswhich can otherwise eaatassisi&te the sponge*

Initiation of the reduction reaction was generally indicatedon the pressure recorder by a sharp drop in the system pressure*Increased system pressure due to excessive sublimation of zirconiumtetraohloride was generally controlled wL-th the help of air-coolingo& the cooling coi l as mentioned above or by bleeding* Occasionallya fa l l in the system pressure WAS encountered which was restored tothe operating range of 1 to 2 pidg either by heat input to -foemiddle aone or by admitting argon. The bottom zone temperature wasmaintained between 850 to 875*0 and was never allowed to rise beyond875°C to prevent the formation of a sLreonium-Aron eutectic alloy*

The manual bleeder r e i v e mounted on the aide pipe was periodically

used to purge the retort atmosphere free from impurities and

corrosion product a •

She end of "the reduction reaotL on was generally indicated

by a continuous f a l l of system pressure even when the middle eone

tesperature was as high as 650*0. At t h i s point the furnace power

was awitohed-off and a l l the unreacted chloride was condensed on

the oooUng c o i l with the help of a ir cooling* The retort was then

allowed to cool to room temperature under a positive pressure of

argon* The oruoible containing the sponge, exoess magnesium and

hyvpro&uet magnesium Chloride was removed from the re tor t , brushed

fr*« of a l l loose material and loaded into the vacuum d i s t i l l a t i o n

unit for tha pyro-vaouua separation of magnesium and magnesium

chloride from sponge«

3 * VACUUM DISTILLATION

3»1 Equipment for Vacuum Dis t i l la t ion

She vacuum d i s t i l l a t i o n system ( i i g . 2) - designed for the

pyro-^raouum treatment of the reduction product for i so la t ing

alroonium sponge from exoess magnesium and by-product magnesium

ohloxlde comprised of the following major component a*-»

A. Hetort

This was fabricated- from AISI 3161 quality stainless steel

(l«D. 460 mo, height 1425 mm). The top section-- designed

for an operating temperature of 9!5O*C under high vacuum -

was fabricated from 19 mm thick plates and the water cooled

lower BeetLon from 6 m thick material* The flanged bottom

section of the retort was connected to a separate chamber

having an elbow leading .to the Taouuu system* Keoprene '0'

sing gaskets were used at a l l flanged joint* to ensure

leak-tightness against vacuum.

The liner assembly fabricated from AISI 316L quality •tain*

leas steel emulated of a 37 mm nominal dia support oolvon,

having three retainer baffles, a salt oatcher, a oruoible

support structure, and a sponge retainer plate.

3* Vaouum system

The vacuum system for the retort consisted of e three stageMgh vacuum o i l diffusion pump having a pumping speed of1500 l / see . backed by a rotary meebanloal pump of 450 l/mcapacity. A vaouostat was used to measure the systemvacuum during operation.

C

The bell type nichrome wound electric resistance furnacemeant for heating the oruoible zone of the retort was ratedat 30 KW. The furnace temperature was automaticallycontrolled by an indicating and controlling pyrometer.

Assembly far Vacuum Distillation

Ihe assembly sequence for vacuum distil lation was as followst-

The support column, carrying the crucible supportstructure, the salt catcher, and the baffle plates,was assembled inside the bottom chamber of theretort. The crucible as obtained after • reductionwas placed over the crucible support in an invertedposition • A thin stainless steel liner was wrappedaround the inner assembly, the retort was loweredinto position and bolted with the bottom chamber*The bell furnace was then placed in position overthe top section of the retort*

3,* Operating Brocedure for Vacuum Distil lation

To start the dist i l lation process, the retort was evacuatedto ft iff vacuum of better than one micron* The retort was then isolatedfrom the pumping system and leak rate observed for a short time. Ifno appneiable leak was noticed, the pumping system was once againconnected to the retort and the charge heated to 850 to 870*0 (as••aaured by the inner couple) avoiding any large pressure excursions,particularly during the stages of drying (*-»2SO«o) and salt melting(710*0). top a 15 kg baton of sponge a disti l lation time of 36 houraat 650 to 87D°C (as measured by the inner couple) was found necessaryfor obtaining sponge Beating specifications with respect to residual

magnesium and chlorine •

The furaaoe power was gwltched-off after the specifieddisti l lation period and the furnace lifted-off from the retort lastags* for accelerated cooling. At a orudble temperature of 75°Cthe vacuum system was out off and argon admitted Into the retort.

3«4 Sponge Conditioning

At room temperature, the freshly exposed surface of zlroontwisponge was carefully conditioned by admitting increasing amounts ofair to form a proteotlTe oxide film making the product safe from fisrenaaards during subsequent handling and crushing. This was aohleredby partial evacuation of the retort and back-filling with room airw&tohing for any abnormal increase of crucible temperature* Theproporti en of air in the retort was Increased ffrom 25$ to 100$ in step*of 23j5 aad at a l l intermediate stages a half-hour soak was givenfor proper conditioning to take place* The soaking time with 100$air was between 1 to 2 hours depending on the baton ed.Ee. AfteroompletLcn of the conditioning cycle the retort was onoe againevrouated and back-filled with argon prior to unloading of cruoible*Material balance of a typical reduction and vacuum disti l lation runas described above I s presented in Tabls=I«

4 . SPONGE HANDLING

After unloading, the sponge from the crucible was careful lyshipped out under a protec t ive cover of argon using non-sparking t o o l sof copper-beryllium* larger pieces of sponge were crushed t o around25 mm alas In a hydraulic press* Further crushing to around 6 ma s i nwas achieved i n a Kue-ken type Jaw Crusher, having jaw» o f corrugatedAssign*

5 . PRODUCT

All m e t a l l i c impurit ies Including hafnium i n zirconium wasestimated by spa otrochemioal methods w i th the help of "prism apectro-graph.udng DO-aro exo i ta t ion technique. For t h i s purpose sponge

samples were calcined to oxide In platinum crucibles.

Oxygen aad hydrogen estimations were carried out in a

direot reading gas analyser using vacuum fusion technique. For

th i s purpose polished pieces of arc-melted buttons were used as

samples.

Carbon estimations in sponge were carried out by to ta l

combustion i n an induction furnace i n an atmosphere of high purity

oxygen aad ihe carbon dioxide produced was quantitatively estimated

by gas chroaatogrephy method.

Nitrogen in sponge was analysed by KJeldahl's method.

Hardness of arc-melted buttons was determined using a ViokerB pyramid

hardness taster*

Table-II presents a typical evaluation report on reactor

grade sponge produoed i n these pi lot plant operations.

6 . PROCESS VARIATIONS ADD OOICLUSIONS

6*1 The following process variations with reepeot to the reduc-

t ion step were investigated i n deta i l t o optimise process parameters*

a) Chloride conditioning schedules;

b) Open syBtem reduction under a continuous argon flow;

c) Bl-metal reductions with magnesium and sodium •

Details on process conditions, results obtained and conclusions

derived with respect to the above are presented in the sequels

6*2 Chloride Oonditloninfl Schedules

Ire-conditioning of the chloride prior to actual reduction

plays a very important role with respect to pressure control during

eaotLon. Two different schedules were examined for pre-conditioning.

Id the f irs t instance, the chloride was gradually heated upto 250°0

under dynaoic vacuum followed by a vacuum soak for 2 to 3 hours

depending on the weight of chloride charged. A rotary vacuum pump

in conjunction with a suitable cold trap was used for this -purpose«

In the second case, after evacuation and back-filling pt the systemwith argon at room temperature, the charge was heated upto 300*0 inan argon atmosphere followed ty a second evacuation backfilling withargoa and heating upto 45O"C with intermediate soaks.

Uth low temperature vacuum degassing, i t was confirmedthat the pressure control during reduction was difficult due toprolonged and gradual evolution of non-ccodensaWte gases such asfef&xogen chloride and other volatile impurities, which were notcompletely removed from -foe oblorlde during pre-conditioning*. Reduction'efficieaeies in this case were only of the order of 65 to 70$ due tofrequent bleeding of system (cooling air on cooling co i l was ineffec-tive due to the presence of non-condensable vapours) in order tos&intain -Use operating pressures in the range of 1 - 2 pslg. Furtherthe sponge obtained after vacuum distil lation was relatively impureanalysing high in iron, chromium, and oai^f^m (2000h 400 „ sad: 1000 ppmrespectively).

In the latter case where the ehlerfcde was. soaked at highertemperatures prior to reduction, the reaction proceeded very smooth])?- the beginning end completion of actual reduction, being indicated bynarked pressure fa l l s in the system. The requirement of air-coolingon control cooling co i l was only occasional since the rate of sublima-tion of zirconium tetrachiorlde could be easily controll d to matchwith i t s actual consumption due to reaction with magnesium* Furtherfor similar batch s i ses , ttie actual reduction time in this case wassignificantly lower compared to the earlier case, where chloride wasonly degassed at a lower temperatures She.end product in this casewas considerably purer with respect to iron, chromium and oxygen(50f 70, and 850 ppm respectively)*

6*3 Open System Reduction under a Continuous Argon Blow

Experiments were conducted} using Hie reduotion equipmentdesoxi bed above, ( i ) as a closed system as described In para 2 above,and ( i l ) as en open system under a continuous argon flow* lor thelatter ruas, an air oool«d condenser was used for effeotive condensation

of unreaoted Chloride, and a sulphfaiic add coluim at -fee exit endof the condenser for maintaining the desired operating pressure inthe system* Ttee aeid column also served as a vent for excess argon*

Reduction efficiencies obtained with the flow Bystemware only of the order of 60 to 70$ since considerable amount ofBireonium tetrachloride by-passed into the air-cooled after-condenseralong; with the argon purge. However, no sophisticated instrumenta-tion was required for such a system for pressure control during thersection, elnoe the system was open to atmosphere through the acidcolunu. Such a system i s simple to operate and easy to control,since one has to guard against only sharp pressure falls to be madegood with argon admittance which can otherwise lead to a back suctLcnof acid/air into the retort*

Quality of zirconium sponge obtained in flow system runswas also inferior analysing some what high in oxygen and nitrogen(1000 end 125 ppm respectively) presumably due to contaminationfrom argon*

On the other hand the success of the closed system operationdepended mainly on the continuous availability of a choke-free argonpurge line through wMoh uninterrupted and reliable pressure monitor-ing was carried out* HLgher reduction efficiencies of the order of80 to 90$ were achieved with the closed system as there was no largeby-pass of unreduced chloride* Quality of the sponge obtained withrespect to oxygen and nitrogen (850 and 15 ppm respectively) was alsobetter compared to the flow system presumably due to the lesserthroughput of argon gas which was a source of oxygen and nitrogenoontamLnatL on •

6*4 Bi-Metal Reduction of Magnesium and Sodium

Bi-metal.reductions of zirconium tetrachloride were alsoinvestigated, using a mixture of 10$ sodium and magnesium as thereducing agent • The reduction was actually performed in two stages- f irst with sodium at around 65O°C The zone temperature was thenraised to 850 to 875°C for the second stage reduction of si,rconiuo

tetraohloride with liquid magnesium aa described above. The reducedproduct was vacuum die t i l led in the conventional way*

She metal obtained by U.-metal reduction was relativelypurer in iron ard chromium (20 and 35 ppm respectively) and alsopossessed a lower hardness of around 125 V.P.N, Improvement in purityoaa possibly be attributed to (i) the lower solubility of impuriti.esl ike iron in sodium metal (as compared with magnesium) and also ( l i )the scavenging action of NaOl on Impurity chlorides. Further, onaccount of the higher thermal conductivity of Nad, heat dissipationduring reduction i s better and the resulting sponge i s less dense,sticks less to the oruolble and i s more easily crushed*

7- CCTOMSIOIf

The above investigations demonstrated the feasibility ofsafely carrying out the reducti en of zirconium chloride vapour withmolten magnesium in a rigidly-closed stainless steel retort,differentially heated in an electric resistance furnace, and usingan argon-purge tube for continuous monitoring of system pressure forprocess control. Better reduction efficiencies were achievable withthis system than by carrying out the reduction under a continuousflow of argon. While quality metal was obtained both in reductionwith magnesium alone and in bi-metal reductions with magnesium andsodium, the purity and orushabillty of the sponge were better in thelatter case* The operating experience was valuable for the design,erection and commissioning of the large scale Zirconium Sponge Plantat the Nuolear Puel Complex, Ifrderabad*

8* A0KNOWIEDOBMS9TB • •.

The authors wish to express t h e i r s incere thanks and

gratitude to

( l ) He Brahm Prekash, Director, Metallurgy Group, and Dr V.K*

Moorthy, Head, Metallurgy SLvisLon, B.A.R.G., for the ir constant

encouragement and keen Interest i n the progress of the above programmes

c . - . > , . v ;; > . l - . - V . - . - - .:••'••--

-13-

(ii) Shrl RJK. Garg, Head, Zirconium Oxide Section, Ohemlcal

Engineering SLvLaLon, 3.A.R.C., for the regular supply of nuclear

grade zirconium 03d.de for the investigations, anl Shrl N. Saratchandran,

Scientific Officer, Metallurgy Division, B.A.R.C., under whose super-

vision the oxide was concerted to anhydrous ZrGl.j

(iii) Dr T.3. Krlahnan (now Head, Quality Control laboratory,

Nuolssx Fuel Complex, Hyderabad) for the detailed evaluation of 1he

various zireoci^jm Intermediates and the final metalj

and (iv) the supporting staff of the Hlot Plant, for their unstioted

efforts throughout the course of the project*

HES'EHEa'CSS

1* R.8. Babu, (Mntamanit F.L. VIJay and R.B. Subramanyam'Studies on the produotion of nuclear grade zirconium spongefrom pure slrconium oxide*B.A.R.C.-427(1969).

2 . O.V. Sundaram et a l .'Pilot plant production of nuclear grade slroonium sponge fromIndian zircon1

A.E.B.T .-201 (1965).

3* H. Saratohandran, R.K. Garg» C.V. Sundaram, and H.C. KatLyar'The present status and the projected programme of zirooniumderelopment in India1

Symposium on decent Developments i n Non-Ferrous Metal Technology*(National Metallurgical laboratory, Jamshedpur, India, December!968) Vol . I l l , pp. 163=172.

4* I . S . Kxtshnan'Analytical quality control i n the production of nuclear gradealrconium and I t s alloys*Symposium on 'Recent DevelopmtartB In Non-7errous Metal Technology*( 4 i y jajsahedpur, India, December 1958) Vol. I l l , pp. 223-230.

5* G*W. Elger,'A comparison of the quality of zirconium prepared by different^aueisxrtsiv • , \Bureau of Mines report investigations USBM-U-702 (January 1961)

TAHLE - I

Material Balance in Magnesium-reduction of ZrOl̂and Vacuum Distillation

Conditions i 1« Reduction temperature t 825 - 875°C

2. Vacuum distillationtemperature .

3* Holding time forvacuum distillation

t Cruoible centre temp* - 850°CRetort wall temp* - 94O°C

t 36 hours

Material in kgs Recovery

Reduction

1. Input(a) ZrCl4 (raw)(b) Magnesium excess)

2. Output

(a) Weight of ZrOl. absorbed

(b) Weight of ZrCl4 undistllled

(c) Weight of ZrOl. in lowerchloride form

(d) Weight of ZrCl. bled and recoveredin the condenser

(e) Unaccounted chloride

49.4

11.4

43.1

1.52.00

1.5

1.3

87.2 %

3.36$

4.48?S

3.36*

2.91$

Vacuum diBtillation .

1* .Inpuh

Reduced material

2* Output ',

(a) Metal recovered(b) losses

54.5

16.000.87

94.8

Overall recovery (based on chloride charged) t 82.7$

-15-

IABIE - II

Analysis of sLroooium sponge produced Inclosed-system reduction of ZrCl. withMagnesium 4

(impurities expressed as ppm)

Al

90

B

<0.5

BL

<25

0

400

Oa

<100

Go

<1O

Or

180

Cu

<25

1*8

100

Hg

160

Mg

500

Ma

75

Mo

<10

IT

. 8 5

Kl

<10

0

865

Sb

< 25

si

< 5 0

Sn

<1O

33.

100

Hardness

150

MAh4UAL BLEEDER VALVE

ARGON PURGE LINE

PNEUMATIC BLEEDER VALVE

COOLING COIL

3 ZONE FURNACE

CHLORIDE CAN

H3SO4. COLUMN

\STEEL MEIZANINE

BAFFLE

LIQUID SODIUM INLET

MgCl2. TAP PORT

FIG, t REDUCTION EQUIPMENT

TITLE REFERENCE

FURNACE

CRUCIBLE

- # * "T .C.

CRUCIBLE SUPPOR T

STEEL MEZZANINE

SALT CAN

WATER COOLING JACKET

QIFr USION PUMP

PJG. 2 VACUUM DISTILLATION ASSEMBLY