SUMMARY OF NFORMATION ON THE SUPEROXIDES OF SODIUM, POTASSIUM 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 Superoxide . Rate of Fo_ :_i_on of Superoxides . I . .ardour C;:wmical Reactions Involving Na, K, or NaK . b , ;H_ Documcntec . ~xi)losions Attributed to Potassium Superoxide 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 <tu fa. es _; s t.; ambient a _ , ultimately to form materia l ni: I)otas a:n suet° 1•o tddt AO ) . _ •otas sium superoxide originally aought to be K204, but magnetic anc_ x-ray analyses demonstrate e~02 . Bubbling gases containing oxygen through liquid NaK also ca r•~suiL in the formation of potassium superoxide after all of the s : . .n as been oxidized. eported in the literature arc a number of explosions which occurred dur___ the handling of oxide 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 . - 1- 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 ;peroxide ? 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 sodium superoxide 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 _ -2- 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 carbon dioxide and water from the wearer ' s exhaled breath .(3 ) The oxides 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 . -3- 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 melting point (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 .