SUMMARY OF NFORMATION ON THE OF , AND Na K

"Compiled By :

E. L . Reed Liquid Metals Information Center October 16, 1969

HDMSP00030591 r

i OF CONTENT' Page In .- ociuction ...... Sc' :cteclilYReference Abstract ~hec :_ ......

PC ..3SSLMan hUD 'OhldC . . - F . e - ......

I . Sodium . . . . . Rate of Fo_ :_i_on of Superoxides ...... I . .ardour C;:wmical Reactions Involving Na, K, or NaK . . b , ;H_ Documcntec . ~xi)losions Attributed to 6 VIII. INK - Pipe-Thread - Sealant Explosions ...... 7 IX. Recommended Cleaning Procedures for K, Rb and C s Containers ...... 7 a Experimental Study of NaK Hazards ...... 8

XI. General Reactions of Na , K, and NaK with Organi c Compounds ...... 9

Resc rences ...... 1 0

.ca ,

A Ti ._uty-three Technical Report Index/ Abstract Sheets A~ - Preparation of Sodium Superoxid e A- - Excerpts from Sodium and Nat1 Engineering Handbook (Should not be further dissern i .iated ) A4 - p=rivate communication from MSA Research Corp ., Evans City, Pa. regarding potassium superoxides AS - Excerpts from Manual of Hazardous Chemical Reactions (1968 ) A6 - USAF C Bulletin No . 251 , "Explosions Involving Metallic K o r Ai - USAEC Bulletin No . 222, "NaK Reacts Explosively with Pipe Thread Sealant " AS - MSA Bulletin, "Cleaning Procedures for K , Rb, and Cs , : ntainers," (May i9 :2 ) A9 - Soc .Ur- Potassium Alloy . An Experimental Study of t-s Hazards (Feb. 1957 ) Ai0 - MSA Bulletin MD-65-1, "NaK and Potassium Technical Bulletin" All - Ethyl Corporation Bulletin, Reactions of Sodium with C :ganic Compounds"

HDMSP00030592 INTRODUCTIO N

'ot Muni alloys of±so.lium and potassium (NaK) wil l e a

eported in the literature arc a number of explosions which occurred dur___ the handling of contaminated potassium and/or NaK attributed tc rid reaction of potassium superoxide with either subsurface un- oxid zed 1otassium metal (or NaK) or with organic materials that have beer. ,s ._4- in attempts to dispose of the material . For example, in one incident a violent explosion occurred during the chipping of a thick oxide crus` frc~n the surface of a potassium metal brick. As will be referenced la _ t: }:nlosi ,n was attributed to the driving of surface superoxid e i Dr_ w_ . :-e underlying potassium metal . Si.niiar incidents will 30 - - _ e explosions have occurred when organic lic, ._d, such oh -r - .Ided to superoxide contaminated potassium. 4.nd/or u_- _g disnosai operations . :.'_-ice >tassium superoxide can form iblent or sli on-dly elevated tempera-. on the surface or walls of vessels . ontair_'- : potassium and/c. : NaK iicre is a definite hay-_rd volved in handling or disposing of these materials . The primary _ia :-: - rd .;.rs to be due to the combination of unreacted potassium me; o _ ctec. NaK in the presence of potassium superoxide because essentially _)ot _ .iur.- superoxide powder is safely handled . Pure pc)----- ssiurn- superoxcc is Y _ :iufactured in ton lots ; its primary use is in car__5te .- _ of self-,_,ntainea breathing apparatus . The recommended disposal p :-_ce- dur-_ ..)f -.)unchi holes in the canister and letting the superoxide react in a llon can of water apparently has'never resulted in an explosion . Hk_ rer, if an organic material or a liquid metal (such as NaK o r pot<. 5iu_n) were to contact the superoxide powder in these canisters an expic .3io=: would result .

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HDMSP00030593 )d_ s-- . .c .-.mot . than ', - Fa~1y does not form at or . :_ ..va Lca:J ) - c: except u •_ 3-,ecial conditions . The

rc _(I ir. __ .e ` -e of sodium peroxid e xidatioo .s above 300C and p .tii raoly between 300 and 4000 ; superoxide- has been preiiarc-1 by reaction of sodium ; ? V_L:_". x~rat 4000 and 1800 psi oxygen p : cssure .( ) Thus the disposal c _ - ;Hated sodium metal does not involve the type of hazar d at• with t :.c disposal of potaE=5ium or NaK . No instances of _iv- reactions with sodium supcsro de were found in the .ac . .atu_-e ._rr: _s a higher percentage of oxygen in tha n is ._.i potassium superoxide . Since sodium superoxide and potassium -)x ~__ are similar compounds one should use the same precautions - :ali..g either of these materials ; however, as already noted, sodiu m .id, _.nd not sodium superoxide is the equilibrium oxide unde r

:ate siurn and sodium superoxides are discussed in greater . deta_- la ;a;_ _ some information is -.resent,_d on the rate of form- of the : :o -.pounds . Also, a number Of razardous reactions in'ving p iu: . : metal, sodium metal, anc. Null with other chemicals are in.-- C, fc - completeness . _Fir.--_,,_ lumber of appendices are attached givi:. s : _ected reference abstract s .ee ._ technical safety bulletins, recomm_-_.ded disposal procedures and general information on some reaf'-ons of potassium, sodium and NaK with organic materials .

IL. SELECTED REFERENCE ABSTRACT SHEET S

Twenty-three Technical Report index /Abstract sheets have been sc ed from 3D9 computer printouts from our data bank as being the r er :_i rent guidance in the safe handling of alkali metals . Eac :: -ter p rintou . is for a single literature reference and gives .=^_ c t'- a Lho-, source, document number , contract number (if perforyne,7. ur goverment cont :iict), descriptive terms (used for retrieval ) , tio:_ ..te , and abs t ract. Literature refer .:=nces include reports, Journal aiic ..cs, and boc .cs . For reports , the listing under Document Ncmnbr _

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HDMSP00030594 rc ~:i, t *: f€ lb' viated titles are used lt__ . n .:: ci]Lxc~. f,,i:rv :n .,ractice of "Coden fo r is ., ~'itles, T1 Special T,:chi : ' lblication No . 329 and _:e .n._ __s . For books, again following Coden practice, the publisher s volume _. .zd page numbers (if appropriate), and publication yea r ate - : a document number . The LM number is a five-digit `•er Nti'_zich our Center assigns to a report when it becomes part o f o:._ to bank. ;'his accession number is primarily for use within the Cc for sequential filing of reports . These abstract sheets are attached as Appendix Al .

III. POTASSIUM SUPEROXID E

. ..um:~ orciai quantities of potassium superoxide (tons per day) are -)y atomizing molten potassium in air . The oxidation product s o ~rvc_-. .__ed consists -~ ? very finely divided yellow powder approaching os :`1'r t.h retical composition of KO2 . For sorrto- tirne .

_ur_ p_ue was regarded as the tetroxide (K204) ; nowr_ver, is studies prover- it to be KO2 . The compound has a melting - .oin . of 380C, a dissociation temperature (at 1 atm .) of 6000, and a iersity of 2 .14 grams per cc . An important use for potassium sup:- _-~xic o is in self-contained breathing apparatus . It is ideal for this pur;-c- :.e because of its ability to control humidity, evolve oxygen, an d remove the and water from the wearer ' s exhaled breath .(3 )

The of interest in NaK, or in any of the alkali metals , are the -_de :M,O, the peroxide (M202), and the superoxide (MO2). The w___ .cs have more available oxygen per atom of metal and _ence c act more vigorously in any oxidation-type reaction. Pota-arum. in ---nominally pure form can be used with relative safe- y in .nt fined breathing apparatus at one should recognize the th exists if this product sho,_ld inadvertently come into ccnta,: _ v --gar-c materials or with potassium metal or liquid NaK . :__-_ur:- for the safe disposal of canisters containing relatively : re po:-s ;,ium superoxide powder was outline: and referenced in the introduction .

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HDMSP00030595 conditions where the is :aratcci <= `V-A t ==f ':etal, it is possible n __ _,acr oxides . Examples -.uch conditions are : (1) on th e ;e j _y r =i - ng on the surface of a weer. pool of molter . ~zta t } an t c wails of a container on whic h t :.. _ - exists a film o .' molten metal ; and (4) in spraying droplets of 'n r..utal thrc;a :,n an oxygen-rich atmosphere .

'ot ., sium ~_ .peroxidc is forme : . mu.-ii more readily than s-3dium

ox. e . Potassium superoxide is made. commercially > ;y dis- `ing a fine spray of molten potassium into an air strea m having an oxygen content of from 13 to 35o by volume in a mixture with - 4- roren. I_:stantaneoas oxidation occurs ; the air stream acts t o qu :-i._.h the- oxide below its (380C) substantially as rapidly s oxide is fanned. The overall reaction is exothermic, whic h .s s :fficie:,-,. heat (about 135 K-cal) to carry the reaction of all tai. __am to _~ompletion.(3) Thug, when exposed to the action of 0:_;r z, .=stassium finally oxidizes to t :-? superoxide KO2, which i s .• ib oxide of potassium at room temperature in the presence of _1 -essures of oxygen.

o ._talysts are mentionec _ .. articles describing the commercia . .ra-_'on of KO2 and apparently none are required. Heavy metal 3, such as copper oxide, nickel oxide, cobalt oxide, and magnesium diox.de, are mixed in the charge of KO2 (when used in self-contained breathing apparatus) to catalyze the reaction of the potassium super- oxiC-= with carbon dioxide and moisture . The reactions of concern in this . .pplL..ation are :

2KO2 + H2O ------ZKOE + 3/2 0 2

2KOH + CO2 ------K2CO3 + H2 O

It is _ .ie . .::ioned in Reference 3 that "It is important, however, ti3ac only a p .io: of the superoxide be mixea with catalyst to avoid excessiv e ._ _ . _ - tic, : of oxygen. "

rently based on K204 ; one-half this value for KO2 .

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HDMSP00030596 _;OiiIUM SU'_EB i ) r

J on .. assive potassium

Nc-. _ toII,, teli.,3cratu ~- c-, £ ivCi~ll cono tions are r ecuire d to t{d €ts of two methods for preparing soc . .um

s i: . . oxiuc are gi .ccn in Appendix A2 .(4) In the first method a solutio n of _L :11 in liquid ammonia wlien oxidized rapidly yields a product cor- to the empirical formula Na3O[ which is though to be a c; and sodium superoxide in the ratio of 1 to 4 . se,.ond rn,;thod sodium per(,,.-..u is oxidized to the higher oxide _:.on ditions of high temperature and high oxygen pressure . Cupric titanium oxide or show considerable promise a s cataly_ts in it p . .Ong the yield of superoxide .

%ce=pts frc_n a preliminary draft of the Sodium and NaK Engineering _.ok . ;.ow being prepared for publication by the Liquid Metal Engineering presented in Appendix A3 . These excerpts indicate that sodium C-)Cic also can be formed by the reaction of sodium vanaz :v 1. lean ,1ressure e'en at a temper :autre of "50'C_ ( Please note thattni&inf. va- tier. AT :, .ndix A3 has not beer, cleared for publication and should not :, d _. aminated. )

V. RATE OF FORMATION JF 5 .. _'EROXIDES

Wher. -potassium supero ;dde is produced commercially by discharging a fine spray of molten potassium metal into an air stream having an oxygen cc_=::- -: of from 13 to 35 percent by volume, in a mixture with nitrogen, the re- -' -n essentially inst.:i :__neous . The -product is a finely divided yello w : p :- . =7n the other hand very inlormation has been published o n t` of superoxide formation on the surface of potassium bricks or on the surface of NaK . Appendix A4 is a copy of a private communication from ti'_SA research Corp. which has some information on this subjectS5) It is Aed therein that the rate of formation of the superoxide in air at ar.lu- temperature or slightly above "is not rapid in terms of hours, out c., . . __ ice appreciable time . " in another private communicationfE it wa

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HDMSP00030597 t} :=r yc_ . i

Cr pit ovc . tsr 2 However, in

.a'` . all of the lo sions attr oi;t• potassium superoxid e ° Svc the pota ., s- uc_ or NTaK had been exposed to nr environments for prolonged periods of time .

of formation of sodium superoxide is slow, even with . .rsts . in table 1 on page 126 of Appendix A2, for example, reaction of_om 1 to 48 hours are listed . In some instances up to 24 hour s _ eruired to obtain maximum y'_elds of the superoxide . In Appendix A2, it is reported that reaction times of 2 hours were used to prepare the super- ox:

VI. HAZARDOUS CHEMICAL REACTIONS INVOLVING Na, K, or NTa K

In ac-u .tier_ tc the dangerous reactions involving potassium superoxide, a nur- ac -)f adcit'_:nal hazardous reactions involving Na, K, and NaK have ec •oport_ _ . In the interest of completeness Appendix A5(7) has bee is c.d wn . . hz lists a number of such hazardous reactions including so: 2x ..sion that were attributed to potassium superoxides on NaK ant: _ .A~,Aic. ,L-ssium. -

1I:... DOCUMENTED EXPLOSIONS ATTRIBUTED TO POTASSIUM SUPEROXID E

Appendix A6 is a copy of a U . S. A. E. C Health and Safety Information Bulletin(s) which delineates explosions involving metallic potassium or NaK mat were documented by the United Kingdom Atomic Energy Authority (U-- . - _'A ;_ Eight incidents of violent explosions are cited that were attributed c-_- to the reaction of potassium superoxide with underlying potassiu m -'-ii (o- NaK) or to the reaction of potassium superoxide with organic

:_terials . Recommendations are made to dispose of potassium and tiaK l yes as soon as possible and t;; '-.andle any such residues suspected tai._ing superoxides only by re--note operations . If it becom es ne essary to stcre NaK residues, dry, air-tigl_t cortainers under an inert atmospi:are are --c-commended. Storage under oil is not recommended .

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HDMSP00030598 ='II rI-IREAD-SEALANT EXPLOSIONS

s t asic. i;ivision of Olitra 5~fi y of the USAEC ha s S ous Accident Bulletion No . 2~ dated March 27, 1964 entitled, :_ . :n- ., ..assiun: Alloy (NaK) Reacts i __ ..osively with Pipe Thread ! a in an incr . :tr^►., : i'F& i glove bo . samples of commercially ~'- .-- .,lc pipe sc :, :ant Lupo were droppe d into a container of 1VaK ; violent :.id :, .met-imes reactions resulted . The trade names of these ',ave been passed on to AEC Field Offices for transmittal to :EC ontractors having need for this information . Appendix A7 gives further information this subject .

_X. RECOMMENDED CLEANING PROCEDURES FOR K, Rb and Cs CONTAINER S

In addition to -potassium and NaK, rubidium and cesium can form su-)e xi _ s, arc ..ic addition of an alcohol to a vessel containing any suc h xi car result in a violent ex .)losion. Appendix A8 is a copy of tit s suet; by Mine Safety Applian/ e Research Corp .' (91 .)n_ c.,eaning ui :or cleaning vessels containing any one of these three metals . M -.1ners have been handled in such a fashion as to definitel y ie entry of oxygen, then an alcohol wash may be used . Methyl a~.- . . i .. = ecommended for potassium ; isopropyl alcohol for rubidium or cesiur_-.. lowever, if superoxides are present, or if their presence is suspected -these must be destroyed before an alcohol wash can be used . Three procedures are recommended for destroying superoxides . These are. i_==ted below :

F -_.ures for Destroying K, Rb or Cs Superoxide s

1 - Heat the entire container to 600 to 800 deg . F for several hours to reduce the superoxides . The top and sides of the container must be heated , too, since these are particularly good sites for superoxide formation . Cool, and then use an alcohol wash.

Iii.: . --Dd 2 - React with dry steam . The steam must be dry and the container must be preheated to prevent condensation.

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HDMSP00030599 .r.ois_ gas_ ~ • --~~ : inert gas can be moistened by ~-,'ater a ' _ - - -, ; .,t necessary to preheat the container .

1 1 . ^ncar= t. b,_ the simplest :r(,._ A.re . Although this bulletin .ot cover tr : nt '?f ti4 071xidct in N7aK, it would be anticipates c .__est same ?~ -o1cciares also apply to NaK . In the case of NaK, n o a ium supc :•r _<< • is formed -uti: all of the sodium has been oxidized '0 .iur. . monoxide .(10~ Thus, if ;.here are potassium superoxides in c ~~ K, he ri_ .ztc riai must be composed+, of sodium monoxide, potassium a d residual potassium metal, ii any.

X. EXPERIMENTAL STUDY OF NaK HAZARD S

Appendix Ac ~s a copy of a report by A. J. Finkel, M. D. and (11 1 W. F . L-_-ons Which is primarily a study of the biological effects of )il_cd on a_:ir. .ul and human tissue . A great number of organic ur e sted in NaK and an appendix was drawn up re,_=.m- ig C. for first %treatment of liquid metal burns . ,mnicdiia .Looding of the area with mineral oil containing addi . ves 5 :)n ; ; ended followed by r c mova> of the liquid metal by scrapin g sh__ p-edged spatula . It is stated that water should not b e i t the burn until after the alkali .-petal has been removed from

_n. particles of liquid metal enter the eyes immediate flushing with uneral oil is recommended . These recommendations conflict with the safety policies now generally accepted at many laboratories where, u::on contu-_ with NaK, it is recommended that the victim be imL_ ctiatti ly placcc under a safety shower so that both kinetic and c .: -.i__ica . reactions will effect a quick removal of the NaK from the _-s bc~ y or 'othes . A multispray type shower was found to be

Est c fectivc _

ie -so of -r_ i icral oil for treating Jody surfaces exposed to NaK _zer than room temperatures is not recommended because- a) Na droplets could be trapped under t :c mineral oil and continue to react with body fluids and tissue , causing further damage ; and b) us of mineral oil in the eye can result in a film residue which woulc co_ -plicate future examination ane treatments .

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HDMSP00030600 1 P~ c ndix A9 thera is one particular item of interest :in i)3W 20, an' -\iai: . j .-lifferent viscosity grades o :_ were s ;p ..___-' ii_ i-~ - _n .; -ILO .Y eiai plates . NaK pellets o. . :nese air:, : _ ;ns of oil ignitccz explosively in less than one

XI. GENERAL REACTIONS OF Na, K AND NaK WITH ORGANIC COMPOUND S

-is a matter of possible general interest two additional appendices '. . -1d A 11) have been included which give a number of reactions o f _ .1, rotassium and NaK with organic compounds . None of these rcac: - ;ns are listed as being particularly hazardous but one should be cons-: .-ntly on guard in organic syntheses against using contaminated potassium: or NaK oxidized to the extent that potassium superoxides may be present.

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HDMSP00030601 r FA C E:

1 . )e_,_cing Instruc-io'_ s for Mine Safety Appliance Chem-ox Breathi ..c iit o . '1V SA- 9942=20 .

Sittig, " Sodium, Its Manufactur e . Properties and Uses , " (Re : old Publishing Corp. , New York City ( 1956) .

3 . C . B . Jackson and R . C . Werner, " Manufacture and Use of , " Advances in Chemistry S eries No . 19, American Chemical S.~ciety, Washington, D . C . (1957) .

4 . V . Schechter and R. H. Slal:ely, "Preparation of Sodium Super- oxiue, " (Mine Safety Appliance Co . , Callery, Pa . ) . Paper presented at the 129th Meeting of the American Chemical Society , Dallas, Texas (April, 1956).

5. Private communication, J. W . Mausteller, MSA Research Corp. , Evans City, Pa . (May, 1967) .

6. Private communication, H. Strahl, Atomics International , Canoga Park, Calif. (Oct . 1969).

7. Excerptq from "Manual of Hazardous Chemical Reactions , " Published < -ional Fire Protection Association, 60 Batterymarch St . , )s~'n, Mass . (1968) .

_,.alth and Safety Information Bulletin No . 251, "Explosions Involvin g to 1ic Potassium or NaK, !I Division of Operational Safety, U. S. A. E. C ., ",Washington , D . C . (Reproduced, with permission, from U. K. A. E . A. Safeguards Buttetin , Issue 2 / 66). (March 13, 1967).

9. "Cleaning Procedures for K . Rb, and Cs Containers , " Mine Safety Appliance Research Corp., Evans . City, Pa. (May 10, 1962).

10. D . D . Williams, J . A. Grand and R. R. Miller , "Determination of the Solubility of Oxygen Bearing Impurities in Sodium, Potassium and Their Alloys , " J. Physical Chem . , 63 pp 63- 71 (1959) .

11 . A . .i . Finkel, M. D. , Ph. D. and W . B . Lyons , "Sodium Potassium Alloy. An Experimental Study of its Hazards , " Thesis submitted by T 1 inkel to the American Academy of Occupational Medicine i n i ifiiment of the requirements for Fellowship . Presented at the -,,nth Annual Meeting of the Academy , Washington, D. C . (Feb . 13-15, 1967) .

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HDMSP00030602