The Radio Chemistry of Beryllium.us AEC

8/7/2019 The Radio Chemistry of Beryllium.us AEC

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1,at iona l~cademy ~~ vofSciencesNat ional Researc h Counc il9 NUCLEAR SCIENCE SERIESThe Radiochemistryof Bery Ilium


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COMMITTEEL. F. CURTISS , Cha irmanNational Bureau o f St a dards

ON NUCLEAR SCIENCEROBLEY D . EVANS , Wce Ch airmanM&3 BWhU8ettB hu vtitu te of Technology

J . A. D eJUREN, S ec re tu r y1 We,vt inghouse Elec tr ic Corpora t ion

H. J . CURTIS G . G . MANOVBrook.haven National Laboratory Tr a ce rla h , In c .WUEL EPSTEIN W. WAYNE MEINKECali fo rn ia Ine t itu te o f Techno logy Un iver s ity o f Mich igauHERBERT GOLDSTELN A. H. SNELLNu clea r Develop men t Co~ra tion of Oak Ridge Na t io n a l Labor a tor yAmerica E . A. UEHLINGH . J . GOMBERG Un ive rs it y of Wash in g to nUn iver s ity o f Mich igan D . M. VAN PATTERE . D. KLEMA Bar tol Re se ar ch F ou n d a tionNor thwes te rn Un iver s i@ROBERT L. PLATZMANArgonne Nat iona l Labo ra to ry

LIAISON MEMBERSPAUL C. AEBERSOLD W. D. URRYAtomic Ene rgy Commimion U. S. Air ForceJ . HOWARD McMILLEN . WILLIAM E. WRIGHTNa t io n a l S cien ce Found a t ion O ffic e of Nava l Re se amh

SUBCOMMITTEE ON RADIOCHEMISTRYW. WAYNE MEINKE, Cha irman HAROLD KIRBYUniver s ity o f Mich igsn Mound LaboratoryGREGORY R. CHOPPIN GEORGE LEDDICOTTEF lor id a S t a t e Un ive rs it y Oak Ridge Na t io n a l Labor a tor yGEORGE A. COWAN J ULLAN NTELSENLos Ah3DiOt3 Eeientific Laboratory Hanford Laborator iesARTHUR W. FAIRHALL ELLIS P, S TEINBERGUniver s i@ of Wash ington Argonne Nat iona l Labo ra to ryJEROME HUDIS PETER C. STEVENSONBrookh aven Na tion a l Labora tory Un ivers ity of Ca liforn ia (Livermore)EARL HYDE LEO YAFFEUn ivers ity of Celifom .ia (Berkeley) McGU1 Un ivers ity

CONSULTANTSNATHAN BALLOU WlLLL4M MARLOWNava l Rad io lo gic a l Defen s e Labor a tor y Na t ion a l Bu re au of StmdardsJ AMES DeVOEUniver s ity o f Mich igan


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C~STRY-RADIATION ANDR4DIOCHEMIST

The Radioc hem ist ry of Bery l l iumBy A. W. FAIRHALLDepartm ent of Chem is tryUn ive rs ity of W as hin gtonS e attle , W as h in gton

bfZly 1960

Su bcomm it tee on Ra dioch em is tr yNa t ion a l Academy of Scien ces Na tion a l Resea rch Cou n cil

P rt n t ed in USA. P ric e $ 0 .7 5 . Ave ile ble fr om t h eOffic e o f Tech n ic a lServices , Depmtmen to f Commerce , Waeh i agtm 2S ,D. C .


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FOREWORDTh e Su bcomm it tee on Rad ioch em is try ie on e of a n u mber ofSu bcommittees work in g u n der th e Committee on Nu clea r Scien cewith in th e Na tion al Academ y of Scien ces -lia tion al Resea rch Cou ucil.

Its m mbers rep resen t govern men t, in du str ia l, an d u nivers ityla bora tories in th e a rea s of n u clea r ch em is try en d an a lyt ica lchemis try .The Su bcom mit tee h as con cern ed it s elf with th ose a rea sof n u clea r s cien ce wh ich involve th e ch em is t , s u ch a s th ecollect ion sad d is t r ibu tion of ra diochem ica l p rocedu res , th e

es tab lish men t of specifica t ion s for rad ioch em ica lly pu re reagen ts ,t h e p rob lem s of s tockp ilin g u ncon tam in ated m ats r ia ls , th e ava ila -b ility of cyclotron t imm for s ervice irra d ia t ion s , th e p lace ofra dioch em is try in th e u ndergra du ate college progrsm , etc.Th in ser ies of mon ogra ph s h a s grown ou t of th e n eed foru p-to-da te compila t ion of rad ioch em ica l in forma tion an d pro-cedu res . Th e Su bcom mit tee h as en deavored to presen t a s erieswh ich will be of m axim um u s e to th e. work in g ecien tia t an d wh ichcon ta in s th e la ta s t a va ilab le in form ation . E a ch mono gr a phcollects in on e volume th e pert in en t in forma tion requ ired fa rradiochemical work with an in d ividu a l elemn t or a grou p ofclosely rela ted elem en ts .An expert in th e rad iwh em is try of th e pa rt icu la r elem en th a s wr it ten th e monograph, followin g a s ta md ard for mm t develop ed

b y t he S ub cca u mit tee. Th e At om ic E ner gy Comm is sion h aa s pon sor edth e prin t in g of th e ser ies .Th e Su bcomm it tee is con fiden t th ese pu blica t ion s will beu sefu l n ot on ly to th e ra dioch em ia t bu t a lso to th e res ea rchworker in oth er fie~ds su ch as ph ys ics , b ioch em is try or med icin ew ho wish es to u seproblem. rad ioch em ica l tech niqu es to solve a spcific

W. Wa yn e Meim k e, Ch a irm anSu b comm it te e on Ra d ioc h em is t ry

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I.

II.III.

Iv.

v.

VI.

CONTENTSGENERAL REVIEWS OF THE INORGMHC AND ANALYTIC&LCHEMIS TRY OF BE RYLLIUMISOTOPE S OF BE RYLLIUMREVIEW OF BERYLLIUM CHEMISTRY OF INTEREST TORADIOCHEMISTSi.2.3.4.5.6 .7 .

Gen er al Ccm s id er at ion aCom plex Ion s of Berylliu mCh ela te Com plexes of Berylliu mSolu ble Com pou nd s of Berylliu IxIIn solu ble Com pou nds of Berylliu mSolven t Extra ct ion of Berylliu m Com pou ndsIon Exch an ge Beh avior of Berylliu m

PROCEDURES FOR DISSOLVING SAMPLES CONTAININGCOMPOUNDS OF BE RYLLIUMCOUNT~G TECHNIQUES FOR USE WITH ISOTOPES OFBERYLLIUM

COLLECTION OF DETAILED RADIOCHEMICAL PROCEDURESFOR BERYLLIUM

12

33458.91016

21

22

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The Radioc hem ist ry of Bery l l ium A. W. FAIRHALL

Depa rtm en t of Ch em is tryUn ivers ity of Wa sh in gton , Sea tt le, Wash in gton

May i960

I. GENERIL REVIEWS OF THE INORGANIC AND ANALYTICAL CHEMISTRYOF BERYLLIUM

Ber@ium, Pp ~97-2i8 , VO1. I. of Th e Chemica l E lemen ts and Th eirCompounds, N. V. Sidgwick , Oxford Un ivers ity Press , Lon don , 1950.Beryllium ,, PP 204-248, VO1. IV of A Compreh en s ive Trea tis e onIn orga nic a nd Th eoretica l Ch em is try, J . W. Mellor, Lon gman s , Greenand Co. , Lon don , i923.Gmelin is Han dbu ch der Anorgan isch en Ch em ie, Sys tem Nr. 26 , 8 th Edit ion ,Ver lag Chem ie G. m . b .H. , Ber lin , i930.Ch apter 32 , pp 5i6-523, Applied In organ ic An alys is, W. F. Hilleb ran d,G. E. F. Lu n dell, H. A. Brigh t and J . I. Hoffman , 2nd edit ion , J oh nWiley aqd Son s , In c. , New York (i953 ).

Beryllium ~ PP 137-148j VO1. I of SCOtiS E$kmda rd Methods of Ch em ica lAna lys is , N. H. Fu rman , editor , fifth edit ion , D. Van Nos t ran d CO. ,In c. , New York, i9 39.L. W. Neid ra ch , A. M. Mitch ell an d C. J . Rodden , pp 350-359, An a lyti-ca l Chem is try of th e Man h a ttan Project, C. J . Rodden , editor-in -ch ief, McGraw -Hill Book Co. , In c. , New York, i950.Non -fer rou s Meta llu rgica l Ana lys is . A Review. G. W. C. MUn er ,mys t q 619 (1956).

* Th is repor t was prepa red a t th e requ es t of th e Su bcomm ittee onRad ioch em is try of th e Comm ittee on Nu clea r Scien ce of th e Na tion a lResea rch Cou n cil as a con tr ibu tion to a proposed m as ter file on th eradioch em is try of th e elem en ts .

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II. ISOTOPES OF BERYLLIUM

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Ill REVIEW OF BERYLLIUM CHEMISTRY OF INTEREST TOJ UIDIOCHEMISTS

i. Gen era l Con sidera tion sIn an y radioch em ica l sepa ra tion of a pa r t icu la r elemen t th e ch em ica l

procedu res wh ich a re u sed a re govern ed in pa r t by th e amou n t of th eelemen t wh ich is pres en t in th e sample wh ich is bein g an a lyzed . Iso -topic ca r r ier , in amou n ts of th e order of m illigram s , a re often addedto th e sample to fa cilita te th e s epa ra t ion s and to determ in e th e th em -ica l recovery of th e radioactive species . k th e ca se of beryllium th eamou n t of beryllium ca rr ier wh ich is to be added to th e sample isgovern ed by wh ich of th e two radioisotopes is of in teres t : Be 7 csntolera te rela t ively la rge amou n ts of ca rr ier with ou t in ter fer in g withth e su bsequ en t cou n tin g efficien cy, wherea s s amples for cou n tin g Be ioshou ld be a s weigh t les s a s poss ib le. For tu na tely radioch emica lprocedu res for berylliu m a re ava ilab le wh ich efficien t ly will is ola teamou n ts of beryllium ran gin g h orn su b-m icrogram u p to macroamou nts .

III perform in g ch em ics3 sepa ra tion s with sen sib le qu an t it ies ofberyllium pres en t it mu s t be born in m t id th a t bery ~um is a veryt~xic ele m en t . Ca re shou ld be exercised to avoid in ges tion of berylliumth rou gh th e mou th via p ipet tes or by in h a la t ion of du s t or vola t ileberylliu m compou nds . If berylliu m-con ta in in g solu tion s a re spilledon th e skin th ey shou ld be r in sed off a t on ce.

Beryllium is th e ligh tes t member of th e grou p II elemen ts . Inkeepin g with it s pos it ion in th e per iodic ch a r t it h a s on ly on e oxida tionn umber , + 2. It is a very good example of th e ru le th a t th e firs t m emberof a grou p shows a s t rong ch em ica l resemblan ce to th e second memberof th e n ext h igh er grou p : in its ch em ica l beh avior beryllium moreclosely resembles a lum in um th an it does oth er members of th e grou p Helements .

Becau se of th e electropos it ive n a tu re of beryllium , an d th e exis ten ceof on ly on e oxida tion n umber for th e ion , exch ange between ca rr ier andt ra cer species pres en ts n o problem so lon g a s th e s ample con ta in in g th emis com plet ely h om ogen eou s . Th e s tron g tenden cy of beryllium toh ydrolyse and form colloida l aggrega tes above pH 5 requ ires th a tca r r ier -tra cer exch ange be carr ied ou t in fa ir ly acid solu tion .

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Many of th e ch em ica l p ropert ies of berylliu m wh ich a re impor ta n tin its rad ioch em ica l s epa ra t ion s a re a s socia ted with its a b ility toform com plex ion s . Th ese complexes will be trea ted fir s t .

2 . Complex Ion s of Berylliu mBecau se of its sm a ll s ize an d it s dou ble ch a rge, th e beryllium ion

h as a s t ron g ten den cy toward th e forma tion of complexes . Th u s th es imple sa lts u niform ly h ave 4 molecu les of wa ter of crys ta lliza t ionper berylliu m a tom , an d th e h ydra t ion of th e Be++ ion form s , a bas isfor u nders ta n d in g th e s t ron g ten den cy towa rd h ydrolys is an d th eamph oter ic p roper t ies of th is species . S ta bility con sta nts for s evera lberylliu m complexes a re given in Tab le I.

Th e s t ron g ten den cy of Be++ Ion toward complex forma tion sh owsu p in a ra th er pecu lia r way by its power to dis solve beryllium oxide.Th e aqu eou s solu t ion of a n y solu ble s a lt of beryllium can dissolve u pto severa l m olecu la r p ropor t ion s of beryllium oxide or h ydroxide,Th e rea son for th is is appa ren t ly th e ten den cy to form th e complex ion

i+Be(OBe)4 , wh ere BeO molecu les h ave rep la ced H20 molecu les int he a qu o com plex.

Table I. Sta b ility Con s ta n ts for Berylliu m Ch ela tes

Ch ela tin g Agen t log Ki

EDTA G3,K q.ace~lacet on e 8 .2

9 .27 .8

oxa lic a cid 4.0ph osph oric acid 2.54

log K2 log K3 Reference

7.77. 8 ..

6 .7

i.8 1 .4

22484922

Th e complex formed between Be ++ an d C204 = , is of some in teres tin a sm u ch as it is th e on ly oxa la te of a d iva len t meta l wh ich is freelysolu ble k wa ter . It is a good illu s t ra t ion of th e d ifferen ce in ch em ica lbeh a t ior of berylliu m from th a t of th e rema tider of th e grou p II

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elements . Th e low degree of ion iza t ion of th e compou nd is eviden ceth a t it exis ts a s a ch ela te complex.

The complex formed between beryllium an d flu oride ion is wor thn ot in g, Exces s flu or ide ion form s th e complex an ion BeF4=, wh ichresembles very closely th e su lfa te an ion . Th u s BaBeF4 form s anin solu b le precipita te an d fin ds a u se h th e fin a l precipita t ion of berylliumin ra dioch em ica l an alyses . Th e solu ble n atu re of sod iu m flu oroberylla tecan be u sed to advan tage wh ere m in era l specimen s a re fu sed withflu orides to ren der th em solu ble. 19 Th e complex is a fa ir ly s tron gon e, bu t may be completely des troyed by th e add it ion of excess H ~130 3.

Beryllium ion is solu ble in i 0~0 (~4)2C0s solu tion a t pH 8.5 -9,p resumab ly becau se of th e forma tion of a comph+x ca rbon a te an ion .Th is proper@ of beryllium h as been u sed in an ion exch an ge tech n iqu efor th e sepa ra t ion of beryllium from copper an d n ickel. 20

The forma tion of a BeH2P04 complex wh ich lim its th e ph osph a tecon ten t of solu tion s wh ich a re to be u sed in cer ta in ca tion exch an ge

2s epa ra t ion s h as been reported .

3. Ch ela te Com plexes of Berylliu mBeryllium form s n umerou s ch ela te complexes with a va riety of

completin g agen ts . These comple~es may be d ivided in to two grou psaccord in g to wh eth er th ey a re n eu tra l or n ega t ively ch a rged.

Neu tra l complexes a re derived eith er from hydro~ -keto compou n ds ,i.e. ~ -keto -en ols , $ -keto -es ters an d h ydroxyqu in on es , or ss e a specia lcla s s of cova len t deriva t ives of czrbo~lic acids . A la rge n umberof h ydro~ -keto compou n ds h ave been s tu d ied as ch ela t in g agen ts hth e ca lorim etr ic determ in a t ion of trace amou nts of beqlliu m. 2 i Fo rdeta ils of th ese p rocedu res th e or igin a l litera tu re sh ou ld be con su lted.

Th ere a re fou r ch ela t in g agen ts wh ich deserve specia l m en t ionbecau se of th e impor tan t roles wh ich th ey p lay in rad ioch em ica l s epa ra -t ion s of beryllium . Th e fir s t of th ese wh ich will be men tion ed iseth ylen ed iamm tietetraa cet ic acid (abbrevia ted EDTA), an d for th e rea sonth a t it form s a mu ch s tron ger complex with man y meta ls th a n it doeswith berylliu m . Tab le II lis ts s tab ili~ con s ta n ts for a n umber of m eta lion s with EDTA. The va lu e of - 3 .8 for beryllium is su fficien t lysma ller th a n th ose of oth er common meta l ion s th a t s ever+ u sefu l

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s epa ra tion s may be ca r r ied ou t u s in g EDTA to preven t in ter feren ce fromoth er meta l species . For example, berylliu m hydroxide may be precip ita tedwith ammon ia h th e presen ce of a lum in um , with ou t th e la t ter p recip ita t in g,if exces s EDTA is presen t . Oth er examples of s im ila r a pp lica t ion s willbe cited la ter .

A secon d very u sefu l ch ela t in g agen t for berylliu m is acetyla ceton e.Th e ch ela te compou nd beryllium acetylaceton a te, Be(C5H70Z)Z is a lowmelt in g (i080 ) vola t ile (b . p . 2700) solid , in solu b le in wa ter bu t solu b lein organ ic solven ts . Th is ch ela te compou n d form s th e ba s is for a

Table 11 , Form a tion Con s tan ts of Meta l - EDTA Completes aCationVa na diu m (ILI)Ir on (III)IridiumThoriumScandiumMercuryGalliumLutetiumYtterbiumThuliumErbiumCopperVanadylNickelDysprosiumYttriumLeadTerbiumGadolinium

[email protected] . i24.9523.223.12i.8020.27i9.83i9 . 5119.3218.85is . soi8 . 7718.62i8 . 3018.09i8 . 0417.93i7 . 37,

M -4n +Y * MYn -4

CationEuropiumSamar iumNeodymiumZticCadmiumPraseodymiumCobaltAluminumCeriu m (III)Lan thanumIr on (II)MsnganeseVa na diu m (II)C&lciumHydrogenMagnesiumStront iumBariumBeryllium

~(n-4)K=+n

M Y-4

log Ki7 . 35i7 . 14i6 . 6 i16.5016.4616.4016. 3i16.13i5.9815.5014.3i4 . 0412.70iO. 96io. 228.698.637.763.8

a In solu t ion s of ion ic s tren gth O. i. Da ta from referen ce 22 , exceptfor Berylliu m , wh ich is from referen ce 2 .

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solven t extract ion procedu re for amou n ts of beryllium as sma ll a s th eca rr ier -free t ra cer (s ee pa rt III-6). Owin g to th e vola t ility of th ech ela te compou n d, ca re mu s t be exercis ed in redu cin g solu t ion s oftracer beryllium to dryn ess wh ere a cetylaceton e h as been u sed , in

23order to avoid los s of th e t ra cer .A th ird ch ela t in g agen t wh ich is u sefu l for th e isola t ion of beryllium

is th e compou nd th en oylt r iflu or oa ceton e (TTA). Th e complex withberyllium is s low to form an d to decompose, a proper ty wh ich makespos s ib le a solven t-extra ction sepa ra t ion of beryllium from a n umber

24of oth er ca t ion s . Th e n on -vola t ili~ of th is complex is an advsn ta geover acetylaceton e wh ere tra cer amou n ts of beryllium a re con cern ed.

The fou rth ch ela t in g agen t of s ign ifica n ce to berylliu m sepa ra t ion sis a cet ic a cid . Beryllium is a lmos t u n iqu e in form in g a series ofcomplex compou n ds with ca rboxylic acids , of th e gen era l formu laBe40 (0- CO-R)6. Th ese compou nds a re n on -ion ized , solu ble in organ icsolven ts , an d vola t ile. Th e bes t kn own of th ese is th e aceta te, bas icberyllium aceta te, wh ich is formed by trea t t ig berylliu m hydroxidewith a cet ic acid or a cetic a n h ydride. It is gen era lly employed forsolven t extract ion of beryllium in rad ioch em ica l an a lyses , a lth ou gh th es ta b flity an d vola t ility of th e complex (b. p . 330 ) perm its its isola -t ion b y d is tilla tion .

The secon d grou p of ch ela te complexes of beryllium are th osewh ich posses s a n ega t ive ch a rge. Complexes of th is type h ave beenprepa red with a n umber of complext ig an ion s in clu d in g oxs la te, m a lon a te,cit r a t e, $a licyla te a nd su lfa te. Th e complex formed with oxa la te h a sbeen u sed in th e back-extract ion of beryllium acetyla ceton e from th e23orgsn ic ph ase in a solven t extract ion procedu re for berylli~m .Complex forma tion with cit ra te h a s been demon s tra ted and u sed in th e24ion exch an ge sepa ra t ion of th e grou p II meta ls . Th e s s lic yla t ean a logu es su lfosa licyla te an d gen t is ic acid (2 , 5 -d ih ydro~lben zoic acid )h ave been u sed as complet in g agen ts in a n ion exch an ge procedu re for

25s ep ar ation of b er ylliu m sn d for th e spectroph otom etr ic determ in at ion26o f b e rylllum .Deta ils of th e solven t extract ion an d ion exch an ge procedu res

in volvin g ch ela te complexes of beryllium will be ou tlin ed in pa rts IH -6an d -7.

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4 . Solu ble Com pou nds of Berylliu mBeryllium hydroxide is a weak base and th erefore solu t ion s of its

s a lts a re exten s ively h ydrolyses , form in g ion s like Be(OH)+ an d++probab ly a lso colloids of th e form (BeO)x Be . Sa lts of su ch weak

acids a s HCN, HZS an d H2C0 ~ a re a lmos t completely h ydrolyses kwater . Th e h ydrolys is of berylliu m solu t ion s leads to th e absorpt ion ofberyllium on to th e wa lls of th e con ta in t ig ves sel. Figu re i sh ows th epercen ta ge adsorp t ion of Be 7 from ca r r ier -free solu t ion s inO. i M NaCl bu ffered with O. 00 i M NAc as a fu n ct ion of pH. 2 Th e pHwas va r ied by add ition of HC1 or NaOH. Absorp tion as h igh a s 20~0on gla s s con ta in ers were observed a t th e h igh er pH ts .

40 -30 -20 -

fGLASS

10- /#*A POLYETHYLENE -0 /.-Q~- ,3 4 5 6 7 e 9

PHFigu re i. Adsorp tion of beryllium on th e wa lls of polyeth ylen e

and gla s s ves sels a s a fu n ct ion of th e pH of th esolu tion . Da ta of referen ce 2.

Beryllium sa lts of s t ron g m in era l acids su ch a s HNO ~, HC1, HBr ,2s04 c104 etc a re a ll qu ite solu b le in wa ter an d th e sa lts th em selvesa re u su a lly h yd ros cop ic. Th e s t ron g ten den cy of beryllium to formcomplex ion s is sh own by th e fa ct th a t th ese sa lts a lways crys ta llizefrom aqu eou s solu tion with a t lea s t 4 molecu les of wa ter per a tom ofberylliu m, cor respon din g to th e tetraa qu Q com plex.

Solu ble complex ion s with F- , oxa la te, cit r a te, et c. h a ve a lrea dybeen men tion ed (pa rts III-2 an d -3).

The act ion of s tron g bases su ch as NaOH or KOH fir s t p recip ita tein solu ble Be(OH)2. a q, bu t add it ion of excess base cau ses th e precipita tet o r ed is s olve . At room tem pera tu re th e volu bility of fresh ly precipi-ta ted berylliu m hydroxide in O. 39 N, O. 65 N an d i. 99 N NaOH is

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reported to be O, 06 , 0 . i44 an d O. 66 moles of Be(OH)2 per liter . 27The solu t ion , h owever, is u n s tab le. On lon g s ta n d in g, or on boilin g,beryllium is rep recip ita ted as a den se crys ta llin e p recip ita te corres -pon dt ig to th e formu la Be(OH) z. The amphoteric n a tu re of berylliumhydroxide is a very u sefu l property in ra dioch em ica l s epa ra tion s , bu twh en ever a s tron g base is u sed to dis solve beryllium from a m ixtu reof in solu b le, n on -amph oteric h ydroxides th e m ixtu re sh ou ld n ot besu bjected to prolon ged boilin g to effect solu tion of th e beryllium les tth e oppos ite of th e des ired resu lt be obta in ed .

5 . In solu ble Com pou nds of Berylliu mTh e mos t impor tan t in solu b le compou n d of beryllium , so fa r a s

rad ioch em ica l s epa ra t ion s is con cern ed , is th e h ydroxide. It isp recip ita ted from aqu eou s solu t ion by d ilu te base. Becau se of th eamphoteric n a tu re of th e fresh ly precip ita ted h ydroxide, th e beetp recip ita n t for beryllium is ammon ium hydroxide bu ffered with ~4+ ion .Th e precip ita te of beryllium , wh ich begin s to appea r a t a rou n d pH 5,is es s en t ia lly in solu b le in an exces s of th is reagen t . Precip ita t ionof beryllium a t th e meth yl red en d poin t (pH -6) IEM been recommended. 28

Precip ita t ion of den se, u nh ydra ted Be(OH)2 from boilh ig Xl&din esolu tion h a s been men tion ed above in con n ect ion with th e amphotericp rop ert ies of b erylliu m . A somewh a t s im ila r res u lt is obta in ed if th ecomplex ca rbon a te of beryllium in ammon ium ca rbon a te solu tion isboiled. In th is ca se th ere is ob ta in ep a wh ite, gran u la r p recip ita te ofbas ic berylliu m ca rbon ate of som ewh at in defin ite com pos it ion .Add it ion of sodium bica rbon a te solu t ion to a solu t ion of beryllium a lsoprecip ita tes bas ic beryllium ca rbon a te. Ign it ion of th e h ydroxides orth e bas ic beryllium ca rbon a te resu lts in beryllium oxide.

Becau se of th e weakn es s of th e a cid , an d th e con sequ en t s t ron gten den cy to h ydrolys is of th e resu lt in g compou nds , th e phosph a tes ofberyllium have a ra th er complica ted ch em is try. At lower pHrs solu b lecompou nds may be ob ta in ed , wh ile a t h igh er pHls in solu ble p recip ita tesof gela t in ou s n a tu re, an d th erefore d ifficu lt to iden t ify, a re formed .However, a n in solu ble crys ta llin e p recip ita te approxim atin g NH4BsP04

29may be obta t ied by add in g (NH4)2HP04 to beryllium solu t ion s a t pH 5 .5.Ign it ion of th e precip ita te resu lts in Be2P207. Th is p rocedu re is

9


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t h erefore u sefu l in ob ta in in g berylliu m in a den se form of kn ownc oppos it ion.

An oth er meth od for p recip ita t in g berylliu m wh ich h as someadvan ta ges over th e oth ers in volves form a t ion of th e BeF4= complexan ion by addition of exces s F - ion , followed by th e addit ion of exces s

++ ionBa . Th e solu tion sh ou ld be acid ified an d on ly a s ligh t exces s++of Ba ion sh ou ld be u sed in order to p reven t th e precip ita t ion of

BaFZ. Th e resu lta n t p recip ita te of in solu ble BaBeF4 is ft ie -gra in edan d very d ifficu lt to filter th rou gh th e u su a l @pes of den se filterpaper . Diges t ion of th e precip ita te for i O m in u tes p rior to filt r a -t ion h elps somewh a t , bu t th e filt r a t ion problem can be overcomecom pletely th rou gh th e u se of RA -type Millipor~ filters . Th e com pa ct ,den se, an d an h ydrou s precip ita te does n ot requ ire ign it ion as do th eoth ers men tion ed above. Th is is a d is t in ct a dvan ta ge in elim in a t in gth e h ea lth h aza rd as socia ted with th e tra n sfer of ign ited berylliu mprecip ita tes , wh ich ten d t o du s t. Th e BaBeF4 precip ita te is mu chmore rea d ily redis solved th an ign ited BeO, bein g ea s ily d i;solved ina m ixtu re of H3B03 an d HN03. TMs is a u sefu l proper ty wh erefu rth er ch em ica l proces s in g is n eeded to remove u nwsn ted rad ioact ivecon tam in an ts from a berylliu m sample.

Berylliu m 1s s tron g ten den cy towa rd h ydrolys is , an d th e in solu bilityof its h ydrot ide h n ea r n eu tra l solu tion s , mean s th a t berylliu m willten d to co-s epa ra te on precip ita tes wh en th e solu t ion is n ot a t lea s t

29m odera tely a cid . Almos t a n y precip ita te wh ich is form ed h a solu t ioncon ta in in g beryllium a t pH-7 will co-p recipita te th e beryllium to someexten t . Pa rt icu la r ly u sefu l in th is respect a re gela t in ou s h ydroxidessu ch as th ose of a lum in um an d iron . Us in g Fe(OH)3 a s th e co-p recip itan t for berylliu m a llows th e beryllium to be recovered from th eprecip ita te by trea tm en t with cold NaOH solu t ion , or by oth er m ean s .

6 . Solven t Extract ion of Berylliu m Compou ndsTh e ch ela te complexes ,of k rylJ ium with a cetylaceton e, TTA, an d

acet ic acid , wh ich were men tion ed in pa rt III-3 above, len d th em selves

* Obta in able from th e M~pore FilterMassachuset ts .

10

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to very u sefu l solven t extra ct ion procedu res for beryllium . Th ese willbe given in deta il below.Ace~lacetone:

By sh ak in g or s t ir r in g aqu eou s solu tion s con ta t iin g beryllium a tpH 4.5 - 8 with ace~la ceton e a ch ela te complex is formed wh ich issolu ble in organ ic solven ts . E ith er pu re acetyla ceton e, as olu tionof acetyla ceton e in ben zen e or CC14 may be u sed . Th e u se of a sm t iqu a n t ity of pu re acetyla ceton e h a s ten s th e forma t ion of th e ch ela tecomplex, a fter wh ich th e complex may be extra cted in to ben zen e oroth er su itab le solven t . Ey s t ir r in g a solu tion a t pH 4.5 , con ta t iin gabou t 1 m icrogram of beryllium with 4 m l of acetyla ceton e for5 m in u tes , an d th en addin g 20 m l of ben zen e an d s tir r in g for 20 m in u teslonger , Tor ibara and Chen fou n d th a t es s en tia lly i 00~. of th eberyllium is tran s fer red to th e organ ic ph as e. 29 Bolom ey a nd Broido 23shook 25 m l of 10~0 a cetyla ceton e in ben zen e with 25 m l of a solu tioncon tah in g ca rr ier -free beryllium tra cer a t pH 6 for 2 h ou rs an dfou n d th a t a ll bu t a tra ce of th e activity was extra cted in to th eorga nic ph as e.

A grea t man y oth er meta l ion s likewis e form ch ela tes with ace@l-aceton e, and u n der th e con dit ion s descr ibed above man y of th em wou lda lso be extra cted . Th e u se of EDTA makes th e extra ct ion more specificfor b er yllium . ~a r in and GHm lo30 s tu died th e ext ra ction of berylliuma cetyla ceton ate in to CC14, CHC13, bu ~l a lcoh ol an d isoamyl a lcoh olcon ta in in g ace@laceton e from aqu eou s solu tion s con ta in in g EDTAan d Al, Fe, and Cr , an d th e diva len t ion s of Co, Fe, Ni, Mn , Zn , Cd,Pb, Cu , Ca an d Mg. Wh en excess EDTA was presen t on ly beryllium wasextra cted in to th e organ ic ph a se. CC14 proved to be th e bes t of th esolven ts wh ich were s tu died . In s t ron gly ammon iaca l solu tion a lum inuman d iron acetyla ceton a tes cou ld s ls o be extra cted .

Th e organ ic ph a se con ta in in g beryllium acetyla ceton a te may bewash ed with acid ified wa ter to remove u nwan ted impu r it ies with ou t23th e los s of appreciable amou n ts of beryllium . Abou t 2 drops ofO. i N HC1 to 25 m l of wa ter makes a s a tis fa ctory wash solu tion fort his p urp os e.

Th e beryllium acetyla ceton a te complex may beth e beryllium back extra cted in to wa ter by sh akin g

11

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con ta in in g t he ch ela te com p lex w it h eq u a l vo lu m es of e it h e r f 0%23oxa lic a cid or 6 N HC1. Bolom ey a n d Br o id o r ep or t t h a t 9670 of

t r a ce r b e r ylliu m is b a ck ext r a c t ed in 2 h ou r s u n d e r t h e se con d it ion s .Tor ib a r a a n d Ch en 29 r ep or t t h a t i 5 m in u t e s s t ir r in g of t h e or ga n icp h a se w it h 5 N HC1 is su ffic ie n t t o t r a n sfe r t h e b e r y lliu m to t h ea qu eou s p h ase . Be ca u se of t h e vo la t ilit y o f ca r r ie r -fr ee b e r ylliu ma ce t yla ce t on a t e , a ce t y la ce t on e w h ich d isso lve s in t h e a cid u se d t o

F igu r e 2.

100 Pti6.72

80 -

60 -

40 -

20 .

60 120 180 240

Ra te of extract ion of Be by O. 04 M. TTA in ben zen e a td iffe r en t p H va lu es . Da t a of Bo lom ey a n d Wish ,r efe r en ce 3i.

b a ck -ext r a c t t h e b e r y lliu m sh ou ld be ext r a c t ed fr om t h e a q u eou s p h a seby wa sh in g t h e la t t e r w it h on e or m or e p or t ion s of fr e sh b en zen e . Th ea qu eou s p h a se m a y t h en be eva p or a t ed t o d r yn e ss u n d e r a h e a t la m p .I f oxa lic a cid is u se d t o a ccomp lish t h e ba ck -ext r ac t ion of b e r ylliu m

23it m a y b e su b lim ed u n d e r a h e a t la m p w it h ou t 10SS of a ct ivit y . Withbe r ylliu m ca r r ie r p re s en t t h e loss of b e r ylliu m t h rou gh vola t iliza tiond u r in g eva p or a t ion of t h e a q u eou s p h a se d oe s n ot a p p e a r t o b e a p rob l em .


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o! -Thenoy l t r i f luo roace te tone :Th en oylt r iflu or oa ce t on e (TTA) is a u se fu l ch ela t in g a gen t for

31m an y m et als , in clu d in g be r ylliu m. Bolom ey a n d Wish h a ve in ve s -

,100- Cu ++ PH 3.40

g ~._1-VuaK-% 60 -w1-ZwQ 40 -awa

20.- FeIUpH 6.38

Al PH3.4,60 120 180 240

F i g u r eTIME (MINUTES)

3. Ra t e of ext r a c t ion of va r iou s m e t a llic ion s by O. 0 i M TTAin b en zen e a t d iffe r e n t pH va lu e s . Da t a o f Bolor n eyWish , r e fe r en ce 3i.

t iga t ed t h e con d i t ion s u n d e r wh ich b e r ylliu m m ay b e sep a r at ed fr oma n um b er of o t h e r m e t a l ca t ion ~ u s in g t h is r ea gen t . I h e com p llexis r a t h e r s low to fo r m a n d t o d ecom p ose . I n F igu r e 2 is sh ow n t h er a t e of ex t r a c t ion of b e r ylliu m by O. 0 i M TTA in b en zen e a t d iffe r en tpH l s . Th e op t im um pH for t h e ext r a c t ion seem s t o be a bou t 7, w it hext r ac t ion of b e r ylliu m be in g es se n tia lly com ple t e in a bou t 3 h ou rs .Th e ext r a c t ion of ir on (I I I ), a lu m in um a n d cop p e r by O. Oi M TTAin b en zen e a t d iffe r en t pH va lu es is sh ow n in F igu r e 3. Ev id en t lya lu m in um is a lso ext r a c t e d qu it e fa vor a b ly a t pH 7, b u t t h e ext r a c t ionof ir on is r e la t ive ly m u ch le s s fa vor a b le a t t h e h igh e r P H .

Th e ba ck -ext r a c t ion of TTA com p le xe s o f Be , Al, Ca , F e , Zn ,Sr a n d Y fr om b en zen e so lu t ion m a d e O. 0 i M in TTA by con cen t r a t ed

13

a n d


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Figure 4.TIME (HOURS)

Back extract ion s of s evera l meta llic ion s withcon cen tra ted h ydroch lor ic a cid . Da ta of Bolomey an dWis h , r efer en ce 35.

h ydroch loric a cid is s h own in Figu re 4. Back extra ct ion of Ca , Fe,Zn , Sr -d Y is complete t i i5 m in u tes . Alum in um requ ires 6 h ou rs ,an d berylliu m a t lea s t 80 h ou rs , for com plete ba ck -extr act ion .However , th e u se of 2 pa r ts con cen tra ted form ic acid to i pa r tcon cen tra ted HC1 accomplish es th e ba ck-extra ct ion of beryllium ina m a tter of a few m in u tes (cf. Sect ion VI, Procedu re i2 ).

Th e solven t exh a ct ion m eth od u s in g TTA works equ a lly well fort racer or m icro am ou nts of beryllium . For tra cer con cen tra t ion s ofberyllium TTA has th e advan tage over acetyla ceton e th a t th ere is n olos s of beryllium th rou gh vola t iliza t ion of th e berylliu m - TTA complex.Acet ic acid .

Wh en fresh ly precipita ted berylliu m hydroxide is evapora ted s lowly32to dryn es s s evera l t im ee with glacia l a cet ic a cid , or wh en berylliu m

14aceta te is h ea ted to 200 C , th ere is formed th e ch ela te compou ndBe40(0-C0 . CH3)6 , bas ic beryllium aceta te. It is a crys ta lXn esu bs ta n ce in solu ble in cold wa ter , bu t rea d ily solu b le t i mos t common

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organ ic solven ts except a lcoh ol and eth er . Ch loroform is th e solven tmos t common ly employed. Th e solu tion of ba s ic beryllium aceta tein ch loroform is rema rkably. s tab le and may be wash ed free of oth erca tion s by ext ra ct in g with wa ter a cid ified with HC1 or with wa ter alone.Recovery of beryllium from t ie ch loroform solu tion may be accomplish edby extra ction with reagen t HNO ~ or by evapora tion of th e ch loroformfollowed by decompos it ion of th e bas ic beryllium aceta te by h ea t in g withcon cen tra ted HNO ~.

Th e prepa ra tion of ba s ic beryllium aceta te is s omewh a t th e-con sum t ig. Th is d isadvan tage is offs et s omewha t by th e specifici~ ofth e procedu re for berylliu m.

7. Ion Exch an ge Beh avior of Berylliu mThe s t ron g tenden cy of beryllium towa rd complex forma tion makes

poss ib le it s sepa ra tion by a va r ie~ of ion exch sn ge tech n iqu es . Th ese=e summarized in Table III an d discu ssed in deta il below.Ca tion Exch an ge Res in s:

Sepa ra t ion of beryllium from oth er ca tion species by ca t ion exch an gemay & accomplish ed h s evera l ways . Berylliu m is s tron gly absorbedon th e ca tion exch an ge res in Dowex 50 a t pH 6 - 8 , presumably owin g toc olloid f o r-ma t ion 2 . At lower pHfs beryllium will pa ss s lowly th rou gh

33 28a ca tion exch an ge res in solumn . Ehman n and Kohman passed ai. i M HC1 solu tion con ta in in g Be and Al th rou gh a Dowex 50 column , andfollowed it with i. i M HC1. At a flow ra te of i res in volume of elu en tper 25 m tiu tes th e beryllium was completely elu ted with 6 or 7 resinvolumes of i. i M HC1. Un der th es e con dit ion s a lum inum begin s to elu teon ly s fter i 2 to i5 res in volumes of i. 1 M HC1 h ave been pa ssed th rou ght he colu m n.

Milton a nd Gru mm itt34 h ave u sed i. 5 M HC1 as elu tin g agen t sn dDowex 50 res in to effect a s epa ra tion of beryllium from th e oth ermembers of th e s lka lin e ea r th fam ily. Th eir resu lt s s re sh own inFigu re 5 .

Honda 35 a n d Kak ih a n a 36 h ave in ves tiga ted th e elu tion of berylliu mfrom Dowex 50 res in by th e u se of dilu te Ca or Mg solu tion s . Th eseca tion s dis place h from th e column , wh ich th erefore pa sses th rou gh ,

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bu t ca t ion s su ch as Al wh ich a re more s tron gly h eld th a n th e a lka lin eea r th s a re reta h ed by th e res in .

Completin g agen ts , for eith er u nwan ted ca t ion s or beryllium , h avebeen u sed in th e s epa ra t ion of beryllium by ca t ion exch an ge res in s .Mer r ill, Hon da an d t in old2 h ave s tu died th e effect of va riou s complet in g

Tab le ILI. Ion Exch an ge Meth ods for th e Sepa ra t ion of BerylliumCa tion E xch a nge

Res in FormmHRHR

HR

~4 R~4 R

NaR

~4 R

NaR

NH4R

RC 2 04

RCitRC1

RC1

E lu t .k g Agen tca iM HC1O. 05 M Ca or MgO. 4 M oxa lic acid

oxa lic a cidpH 4 .4 -50 .55 M bm .la c.pH 5i 0%(NH4)2C0 ~PH 8 . 5 -9EDTA, pH 3. 5-4.0

0.35 M aceta te

acetylacetonepH 50.0 2 M s ulfos ali-cylic a cid pH 3 .5 -4 .5

Ion s E lu t edBeBeAl, Fe+, U02*Th , ot her sAl, Fe

BeBe

Al, Fe3+, Mn++h ea vy m eta ls ,othersBe

Be

Be

Ion s Re ta in edAl, Mg, Ca , Sr , Ba

Be

Be

oth er a lk . ea r th sCu , Ni

Be, a lk . ea r th s

Al, a lk . ea r th s,U, oth ersAl, a lk . ea r th sU, oth ersCu , U, Ca

h ion Exch an geO. i M oxa lic a cid Be N0.45 M HC1i M amm . cit . pH 8 Be oth er a lk . ea rth sv~iou s con e. HC1 Be m a n y t ra n s it ion

elementsi3 M LiCl a lk . m et als , Be

Mg

Reference28 , 34 , 3535 , 362

37

3420

2 , 38, 39

2

2

25

28

2440-42

43

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Io.o ?:: 6elo 20 3040 maolooI , I 1 I m , 1 1 I

20ELUATE VOLUME (ml)Figu re 5 . Th e sepa ra t ion of berylJ iu m , m agn es ium , ca lcium ,

an d s tron t iu m by ca t ion exch an ge u s in g i. 5 Mhydroch loric a cid elu an t . Dowex 50 column i. ix 8 cm , flow ra te 1 .0 m l/ m in , T w 600 C. Da taof Milton an d Gru rnm it t , r eferen ce 34.

a gen t s on th e u p take of berylliu m by Dowex 50 res in . Be7 wa s u sed asa tra cer in th ese exper imen ts wh ich were condu cted a t room tem pera tu re,/23 - 250 C. Th ey defin e th e d is t r ibu t ion coefficien t of Be, Kd , to be

Be7 adsorbed / g res ind = Be7 rema in in g / m l solu t iona t equ ilib r ium . For pu rposes of n orm a liza t ion th ey s lso defin e th edis t r ibu tion coefficien t , D, to be

++D= 7 adsorbed lg res in

Be rema tiin g / m l solu t ionmeasu red in th e absen ce of complex agen ts .

In O.i MNa+ , an d with th e res in in th e sod ium form , D wasmea su red to be 700 for 200-400 mesh res in an d 830 for 50-i OO meshres in . In O. i M H+, a n d with th e res in in th e h ydrogen form , D wa s

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measu red to be i870 for 50-100 mesh res in . Th e va lu e of D was fou ndto va ry with th e con cen tra t ion , C, of th e mon ova len t ca t ion in th e, solu tion ,and in th e n eighborh ood of th e con cen tra t ion s wh ich were u sed D va ried

i Kas _. d ~e sh ow-n in Figu re 6 plotteda lu es of th e qu sn tia _2 Daga in% th e con cen t ra t ion of completin g agen t for severa l cas es .

Stab ility con s tan ts were ca lcu la ted for th e s evera l complexes fromth es e ca tion exch an ge da ta and are given in Table I, page 4.

Becau se cer ta t i u nwan ted ca tion s may form mu ch s tron ger complexesth an does beryllium , th e u se of complet in g agen ts su ch a s EDTA oroxa la te can be qu ite effective in isola t in g beryllium from a mktu re of

1,0(

0.14

KdT

0.0

O.oc

o

x~J1 t I 1 I 1 1 I 1 1 1 i12 II lo9e 76543 21

-LOG [An-]CONCENTRATION OF COMPLETING AGENT0 . EOlA(Y4-1,0.0SM Na+-Na R u . OXAMTE (A=kQl M Hi++aR~ . AC:~N~:ETONC [A-), 0.1 M + s P~SWRIC ACIO (A-) 0.05 M H+-HR

q = HcPOo-(A-l. O.IU N#-Na RM = OXALIC ACID [d), 0.1 M H+-HNA s OXALIC ACFO&), D. I M M+-No R

Figu re 6 . Uptake of beryllium by Dowex 50 res in fromsolu tion s con ta t iin g var iou s com pletin g agen ts .Da ta of Merr ill, Honda , an d Arn old , referen ce 2.

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ca tion s . EDTA is especia lly u sefu l in th is respect , pa r t icu la r ly in th esepa ra t ion of beryllium from iron and a lum in um . Table lY sh ows th esma ll u ptake of a lum in um by Dowex 50 wh en excess EDTA is pres en t . 2Us in g Amber lite IR-i20 res in in th e sodium form Nadka rn i, Va rde andAthavsle38 fou n d th a t from solu tion s con ta in in g excess Na2H2 EDTA .a t pH 3.5 beryllium was absorbed by th e res in wh ile a lum in um , ca lciumand t ion passed th rou gh th e column . If H202 was pres en t t itan ium a lsopa ssed th rou gh th e column u nabsorbed by th e res in .

Oxa lic acid is u sefu l for th e sepa ra tion of beryllium from su ch ion sa s Fe 3 , Al+, U02+2, s n d Th+4. Oxa lic a cid , O. 4 M solu tion , may be

2u sed to elu te th ese ion s wldle beryllium is reta in ed on th e column .Rya bch ikov a nd ESu kh tia rov 37 repor t th e sepa ra tion of beryllium from t ionan d a lum in um by th e u se of oxa la te a t pH 4.4 . Iron an d a lum inum passth rou gh a s complex ion s wh ile beryllium is reta in ed on th e column .

Th e sepa ra tion of beryllium from magnes ium an d t ie oth er a lka lin e

Table IV. Uptake of Alum in um by Dowex 50 from Solu tion sCon ta in in g Excess EDTA

Volume of solu - p H &for e pH a fter Al absorbedt ion pa ss ed a pas s in g ~a s s in g (mmole / g res in )

50 2.79 -- 0.1930 3.10 3. 2 i 0.00730 3.62 3.78 0.00350 3.52 3.61 0.0026

a Sam ple solu tion : 0.22MNa++0.iMAlY- + O. Oi M excess EDTA+ S04=; CaCO q added to adju s t PH. Da ta of Merr ill, Honda , andArn old , referen ce 2.

ea r th s by mean s of ammon ium lacta te h a s been described by Milton an dGrummit t . 34 Us in g O. 55 M ammon ium lacta te a t pH 5 as th e elu sn t , aflow ra te of i m l/ m in . , an d a Dowex 50 column mdn ta in ed a t a temper-a tu re of 78 C, beryllium was elu ted from a i. i x 8 cm column in lessth an 2 in ters t it ia l column volumes . Th is was con s iderably h advan ceof magnes ium , wh ich began to elu te a t s rou nd 2.5 in ters t it ia l columnvolumes.

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Th e u se of s a licyla te a n a logs for s elect ive elu tion of berylliu madsorbed on a Dowex 50 res in column h as been repor ted by Sch u ber t ,Lin den ba um a nd Wes tfa ll. 22 Us in g O. 02 - 0 . iO M su lfosa licylic acid a tpH 3 .5 -4.5 beryllium is s elect ively elu ted wh ile Cu +, U02++ ++an d Caion s rema in firm ly on th e colu mn . If iron is s lso adsorbed on th ecolumn it ca n be elu ted before th e beryllium with O. i M su lfos a licylic a cid a t pH 2 . i.

Wh en O. i M gen t is ic acid a t pH 6 .0 is u sed to elu te a Dowex 50++ ++colu mn (H - form ) con ta in in g adsorbed Ca an d Be ion s t he b er ylliu m

comes off in a sh a rp ban d , begin n in g wh en th e pH of th e efflu en t rea ch es1 .9 , rea ch in g a maximum at pH 2.74 an d complete wh en th e efflu en t

25rea ch es pH 5.60. Un der th es e con dit ion s ca lcium is s t ill r eta in ed ont he colu m n.

Sta r t in g wit i i50 m l of solu t ion con ta in in g i. i g of CaC12, 5 pg ofBe, an d O. i M in s u J fosa licylic acid a t pH 4 .5 , th es e a u th ors pas sed th esolu t ion th rou gh a colu mn con ta in in g i5 g of a ir-d r ied Dowex 50 res inwh ich h ad been equ ilib ra ted with O. i M su J fosa licylic a cid a t pH 4 .5 .Beryllium pa ssed completely th rou gh th e column with th e a id of 70 m lof was h solu t ion (O. i M md.fosa licylic a cid a t pH 4 . 5) wh ile ca lcium wascom plet ely a ds or bed .

Rap id elu t ion of berylliu m adsorbed on a ca t ion exch an ge res inwh ich h a s been wa sh ed free of u nwan ted ca t ion s may be accomplish edby s t ron g ( >3 M) HC1, 333844 or by a solu t ion of O. 5 M NaAc an d1 M ~C2. In the la t ter ca se O. 5 - i. 5 colu mn volumes of efflu en tcon ta in dl th e berylliu m , wh ich may be recovered as Be(OH)2 bya dd hg NH40 H2.An ion Exc h a nge Res in s :

Th e u se of an ion exch sn ge res in s h th e sepa ra t ion of m eta l ca t ion sim plies th e for in a t ion of n ega t ively ch a rged complex ion s , eith er of th edes ired elemen t to be sepa ra ted, or of u nwan ted im pu rit ies . As amexample of th e la t t er , in h ydroch loric a cid solu t ion berylMum does n otform a complex with ch loride ion of su fficien t s t ren gth to be absorbed

45on Dowex I res in . A grea t m an y oth er meta l ion s do, h owever ,form ch loride complexes wh ich a re a bsorbed by Dowex I res in . 40-42Beryllium may th erefore be sepa ra ted from th ese elem en t s by s implypa s s in g th e solu tion in h ydroch loric acid of appropria te s t ren gth

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th rou gh a Dowex I res in column . Unwan ted ion s will be adsorbed wh ileberylliu m will pa ss th rou gh u mdsorbed.

Even th ou gh beryllium shows n egligib le adsor@ion on to Dowex I res infrom i2 M HC1 solu t ion s , it is in teres t in g th a t th ere is adsorption ofberyllium from i 3 M LiCl solu tion . 43 With a dis tr ibu tion coefficien t of8 in th is solu tion (Be adsorbed per Kg res in / Be remakin g per literof s olu tion ) beryllium cou ld be sepa ra ted by an ion exch an ge from n on -absorbable elemen ts su ch a s a lka li m eta ls an d magn es ium by th is tech n iqu e.

,h ion exch ange s epa ra tion s of beryllium based on th e forma tion ofn ega t ive complexes of beryllium do n ot appear to h ave been exten s ively

28used , Ehmam I an d Kohman have u sed th e oxa la te complex ofberylliu m to effect radioch em ica l pu rifica t ion of berylliu m. BerylJ iu mch lor ide solu tion , a fter evapora tion to dryn ess was taken u p h O. i M2c204 -0 . i5 M HC1 (pH = O. 9) s olu tion an d passed th rou gh a 4 x i/ 2column of Dowex I res in a t a flow ra te of i m l / m in . Elu tion was byth e s ame solu tion , wh ich effected th e eleu tion of beryllium in 5 res involumes.

Nelson and Krau s 24 s tu died th e sepa ra t ion of th e a lka lin e ea r thelemen ts by an ion exch an ge u s in g citra te solu tion s and Dowex I res in .Beryllium is more s tron gly absorbed th a n th e oth er members of th ef am~ a t low cit ia te con cen tra tion s, a lth ou gh a t cit ra te cor icen tra tion sgrea ter th a n abou t O. 1 M magn es ium is more s tron gly absorbed th anberyllium . Effect ive sepa ra tion of beryllium from Ca , Sr , Ba and Ramay be accomplish ed by th is tech n iqu e, bu t th e sepa ra t ion from magn e 13iumis les s s a t is fa ctory. Us in g i M (NH4) 3Cit a t pH 8 beryllium comes offfirs t , bu t th e la s t por t ion of beryllium will be con tam tited with magn es ium .Altern a tively, u sin g O. 2 M (NH4) 3Cit a t pH 4.3 magn es ium comes offfirs t bu t ta ils badly an d con tam in a tes th e beryllium as it is elu ted fromt he colu m n.

IV. PROCEDURES FOR DISSOLVING SAMPLES CONTAININGCOMPOUNDS OF EERYLLIUM

In asmu ch a s th e common sa lts of beryllium , th e ch lor ide, flu or ide,n itr a te, s u lfa te etc. , a re freely solu ble in wa ter , th e problem of

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d is solvin g th e sample is th a t of ren der t ig solu ble th e m a t r ix ma teria lin wh ich th e berylJ iu m is t ibedded . For th e specia l ca se of befylliu mmeta l its elf th e bes t solven ts a re h ydroch loric or su lfu ric acid . Th em eta l a lso d is solves in a lka li h ydrot ide solu t ion s owin g to th e amph otericch ara cter of th e elem en t. Nitr ic acid , eith er con cen tra ted or d ilu te,i s n ot a su ita b le solven t for it r en ders th e meta l pas s ive.

Th e ra dioberylliu m con ten t of meteor ites an d of va r iou s sed im en tsan d rocks is of con s iderab le in teres t to th e geoch em is t . For iron meteor it em a ter ia l aqu a regia is th e solven t common ly employed . For s iliceou sma ter ia ls HF is th e appropria te solven t ; th e s ilica is vola t ilized ,elt iin a t in g a _ an d oth erwis e trou b lesome compon en t from th esam ple. At th e same t im e th e berylJ ium form s a complex with flu oridewh ich shou ld en su re good ca r r ier -t ra cer exch an ge. However, ca resh ou ld be taken to decompose th e flu or ides , an d th e berylliumcomplex, before proceed in g with th e sepa ra t ion . Th e BeF4 = comp le xion is s idk r h beh avior to th e ~4= an ion . Th e bes t m eth od fordes troyin g th e BeF4= complex is to t rea t th e sam ple with HBO ~ a fter th ebu lk of th e flu or ides h ave been decomposed by trea tm en t with HNO ~ orH2S04.

Becau se of th e forma tion of BeF4= complex ion with flu orides , th eu se of a NaF fu s ion to ren der solu ble th e beryllium in s iliceou s samples

19h a s been repor ted by Ru ra l .

V. COUNTING TECHNIQUES

cou n t in g of Be 7

FOR USE WITH ISOTOPES OF BERYLLIUM

The on ly observable ra d ia t ion from Be 7 is a y ra y of O. 477 Meven er~ em it ted in N ii?~. of th e decays (s ee Pa r t U). Scin t illa t ioncou n t in g is th e obviou s ch oice for detect ion of th es e y ra ys . Becau se

+of th e pos s ib ility th a t oth er y-em it t in g species , or ~ -em it t in g specieswh ich wou ld give r is e to O. 54 Mev an n ih ila t ion qu an ta , m igh t bepres en t in th e sample th e cou n t in g of Be 7 can be don e with as su ran ceon ly if a y ra y spectrometer is ava ilab le for exam ih in g th e y ra yspectrum from th e sam ple.

In add it ion to th e criter ion of rad ioch em ica l pu r i@p i. e. th eberylliu m sample for cou n t in g mu s t s h ow on ly a O. 477 Mev y ra y,

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on e m a y a lso r e qu ir e t h a t t h e sam p le em it n o p a r t ic le r ad ia t ion s .?7s in ce Be em it s n on e . I n p a r t icu la r } t h is is a r eq u ir em en t w h en Be 7

is p r od u ced in n u clea r r ea ct ion s in t h e la b or a t or y. 44.s d is cu ssed inP ar t 11, p r od u ct ion of (3-em it t in g Be 40 in s ign ifica n t in ten sit ie s int hese in st an ce s is n eglig ib le . F or t h e s t u d y of Be 7 p r od u ced in n a t u r eby cosm ic r a y a ct ion , Be 40 i6-4,8is a lso kn own to be produ ced so-t h a t a low in t en s i t y of (3 em iss ion fr om Be it l is t o b e exp ect ed .

A t h ir d cr it e r ion of t h e r a d ioch em ica l p u r it y o f a b e r y lliu m sam p leis t h e h a lf-li fe for d eca y of -t h e sam p le t w h ich sh ou ld be 54 d a y.Be ca u se of t h e lon g t im e la p se r eq u ir ed t o es t a b lish a h a lf-life o ft h is m a gn i t u d e , p a r t icu la r ly fo r sam p le s of low a ct ivit y , it is ge n e r a llyd es ir a b le t o e s t a b lish t h e r a d ioch em ica l p u r i t y o f t h e sam ple by ot h e rme a n s .

Wh e r e o t h e r m ea n s of e s t a b lish in g t h e id en tit y of a r ad ioa ct ivesp ec ie s a r e la ck in g? t h e con st a n cy of t h e sp ecific a c t ivit y (cou nt in gr a t e p e r m g of sam p le ) of t h e sam p le w h en p u t t h r ou gh a n um b e r ofr ad ioch em ica l p ur ifica tion s t e p s is u su a lly su ffic ie n t t o d em on st r a t et h a t t h e a ct ivit y is isot op ic w it h t h e e lem en t of t h e sam p le ,

Th e m ost d ifficu lt s it u a t ion fo r e s t a b lish in g t h e p r e se n ce ofBe 7 in a r a d ioch em ica lly p u r e con d it ion in a cou n t in g sam p le a r ise s w h ent h e in t en s i t y is ve r y 10W9 of t h e or d e r of 30 c /m or le s s , in wh ich ca sei t m a y be ve r y d ifficu lt t o ob t a in a n a ccu r a t e y r a y sp ec t r u m or t od e t e c t low in t en s it ie ss or p a r t ic le -em it t in g im p u r it ie s . On e m ust t h e nfa l l back on t h e con s t a n cy of t h e sp ecific a c t ivit y a s a cr i t e r ion fore s t a b lish in g t h e id en t i t y of t h e a ct ivit y w h ich is b e in g cou n t ed . On em u st t he re fo r e have a ve r y r elia b le a n d sp ecific r ad ioch e r nica l p r oced u r efo r b e r ylliu m in or de r t o m in im ize t h e p oss ib i li t y o f h av in g a . r ad ioa ct ivecon tam in an t in t h e cou n t in g sa mp le . En t h is r e ga r d it is w or t h d r aw in g202a t ten t ion to th e n u clide T1 ~ wh ich decays by K an d L cap tu re toHg 202 with t h e em iss ion of 0.44 Mev y rays . Its y ra y en ergy is soclose to th a t of Be 7 th a t th e ch an ce of produ cin g th is species byn u clea r rea ct ion s on m ercu ry an d lead isotopes sh ou ld n ot be overlooked .

Th e closen es s in en ergy of th e y ra y of Be7 to O. 5 i Mev a nn ih ila tionqu an ta makes ra th er ea s y th e determ in a t ion of a bsolu te d is in tegra t ionra tes of Be 7 sam ples . Solu t ion s of th e (3+-em it t in g species Na 22w h ich h ave b een a ccu r at e ly s t a n da r dize d fo r t h e ir a b so lu t e sp ecific

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act ivit ies a re commercia lly ava ilab le for ca lib ra tion pu rposes .Provided th e sou rce is su fficien t ly th ick to s top a ll pos itron s , th era te of em is s ion of O. 51 Mev an n t ifla t ion qu an ta will be ju s t twice th epos itron emis s ion ra te of th e sou rce. The sou rce may th en be u sed todeterm in e th e detect ion efficien cy of th e scin t illa t ion detector forO. 5 i Mev qu an ta , wh ich will be very close to th e detect ion efficien cyfor O. 477 Mev qu an ta .

Na 22 h as also a i. 28 Mev y ray wh ich complica tes ma tters somewh a t ,s in ce th is y ray will a lso give rise to some pu ls es equ iva len t inen ergy to those a ris in g from O. 54 Mev qu an ta . In order to get a rou ndth is Mficu l& it is n eces s a ry to determ in e th e detect ion efficien cy ofth e s t in t .illa tor in th e n eigh borh ood of th e O. 5 i Mev ph oto peak. Th isis bes t done u s in g a scin t illa tion spectrometer with a win dow wh ich canbe opened to s tradd le th e ph otopeak. Con tr ibu t ion s to th e observed

22cou n t in g ra te with in th is win dow from th e 1.28 Mev y ra y of a Nasou rce may be es t im a ted in th e followin g way. The cou n t in g ra tesin th e en erw region a lit t le above and a lit t le below th e O. 51 Mevph otopeak is firs t m easu red u s in g a ra th er sma l l win dow to obta in th ecou n t in g ra te per u n it win dow wid th in th ese two region s . Th esecou n tin g ra tes will be a lmost en t irely du e to i. 28 Mev quanta, an d canbe u sed to es t im a te th e con tr ibu t ion to th e cou n t in g ra te in th e regionof th e O. 5 i Mev photopeak by in terpola tion between th em . In a typ ica l2 t ich well-type scin t illa t ion detector th e con tr ibu t ion from 1.28 Mevqu an ta to th e cou n t in g ra te h th e O. 5i Mev photopeak amou n ts to abou ti 7% of th e tota l.

Havin g es tab lish ed th e cou nting ra te, R, of a n n ih ila t ion qu an ta wh ichfa ll with in th e win dow of th e spectrometer , th e detection efficien&, E,of th e spectrometer with th e win dow s traddlin g th e O. 5 i Mev ph otopeakis given by

E = ~.fa

D is th e pos it ion em is s ion ra te of th e sou rce an d fa is a factorto correct for absorpt ion of O. 51 Mev qu an ta with h th e sou rce. Providedth e sou rce is n ot too th ick , fa is n ot a very s ign ifica n t fa ctor , an d canbe made to can cel a s im ila r correct ion factor for beryllium if th eNa22 sample is abou t th e same th ickn es s a s th e beryllium samples .

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Havin g d e t e r min ed t h e cou nt in g e ffic ien cy of t h e sc in ti lla t o r fo rO. 54 Mev qu a n t a , t h e b a se lin e o f t h e sp ec t r om e t e r is sh ift e d d ow nw a r da n a p p r op r ia t e am ou n t so t h a t t h e w in d ow of t h e sp e ct r om e t e r s t r a d d le st h e O. 477 Mev, p h o t op ea k of Be7. Th e sam e w in d ow w id t h sh ou ld b e u seda s fo r t h e O. 5 i Mev a n n ih i la t ion p h ot op e a k ~ in w h ich ca se t h e d e t ec t ione ffic ien cy of t h e sp ec t r om e t e r is ve r y close t o E . F or a t yp ica l 2 in chw e ll -t yp e scin t illa t ion d e t ec t o r E h a s a va lu e of a b ou t 6 p e r ce n t fo rO. 5 Mev q u an ta .

Res t r ic t in g t h e en e r gy in t e r va l in wh ich p u ls e s w ili b e cou n t ed t ot h e p h o t op ea k r e su i t s in a n a p p r ecia b le loss in cou n t in g r a t e of t h esou r ce ove r t h a t wh ich cou ld be ob t a in ed if a w in d ow w er e n ot u se d . Wit h

7s t r on g Be sou r ce t h e d is in t e gr a t ion r a t e of t h e sou r ce cou ld b ed e t e r m in ed a s ou t lin e d a bove a n d t h e sam p le u se d t o d e t e r m in e t h ecou n tin g e ffic ien cy of a sc in ti lla t ion cou nt e r w h ich cou nt s a ll p ulse s a b ovea m in im um t h r e sh old . Th is is sa t is fa c t o r y fo r sou r ces w it h cou n t in gr a t e s in e xces s of a few h u n d r e d cou n t s p e r m in u t e . Wit h ve r y w ea ksou r ces j h ow eve r p cou n t in g w it h a w in d ow is u su a lly t o b e p r e fe r r e db eca u se ii r esu lt s in a m or e fa vor a b le sam p le -t o -b a ck gr ou n d cou n t in gr a t i o .Cou nt in g of Be 40

Beca u se of t h e lon g h a lf li fe of Be 10~ a n d t h e fa ct t h a t th is n u clide islikely to be of im por ta n ce on ly in n u clea r rea ct ion s p rodu ced th rou gh th eact ion of cosm ic ra ys , th e d is in tegra t ion ra te of a n y sample con ta in in gBe $0 will be very sma ll in deed . Wh en th e low p decay en ergy ofO. 555 Mev is con s idered a lso, th e cou n t in g of Be 40 becom es a form idab leta sk . Eviden t ly Geiger or p roport ion a l cou n t in g of th in samples insom e t yp e of low le ve l cou n t e r is ca lle d fo r .

Sin ce p r oced u r es a r e a va ila b le for iso la t in g be r ylliu m in ca r r ie r -fr e e am ou n t s , cou n t in g sam p le s wh ich a r e ve r y t h in ca n b e p r e p a r ed .P r e su m a b ly t h e t h ick n e ss o f t h e fin a l sam p le is lim it e d by t h eb e r ylliu m con t en t o f t h e s t a r t in g m a t e r ia l w h ich is a n a lyse d . I fsu ch a ca r r ie r -fr ee se p a r a t ion w e r e a t t em p t e d t h e r ecove r y e ffic ien cyo f B e 7cou ld b e ob t a in e d by m ea su r in g t h e r e cove r y of a Be sp ikew h ich w a s a d d ed a t t h e b eg in n in g of t h e a n a lys is . Of cou r se t h e am ou n tof Be 7 sp ik e t o b e a d d ed sh ou ld be ch osen so t h a t i t s cou n t in g r a t e d oe s10n ot ove r w h e lm t h a t d u e t o Be . Th e m uch low er cou n t in g e ffic ien cy

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of Be7 y rad ia t ion in a Geiger or p roport ion a l cou n ter mean s th a trou gh ly i 0 0 t im es th e d is in tegra t ion ra te of Be 7 compared with Be iomay be presen t in th e sample before th e accu racy of cou n t in g ofBeio i8 imp a ir ed .

Th e iden t ity of Be 10 in a sample from th e ca r r ier -free sepa ra t ionof beryllium cou ld be determ in ed in a man n er s im ila r to th a t wh ich is

10u sed wh en ca r r ier ia p res en t . Th e con s tan cy of th e ra t io of th e Becou nt in g ra te to th a t of Be 7 t ra cer , wh en repea ted ch em ica l s epa ra tion sa re performed on th e sample, shou ld su ffice to demon s tra te th a t an y13a ct ivity is du e to Beio.

Becau se of th e complexity of th e ch em ica l s epa ra t ion wh ich m aybe requ ired in some in s tan ces for isola t in g beryllium in a pu recon d it ion , or in h igh yield , it m ay be n eces sa ry to add berylliu mca r r ier . In th is ca se th e fin a l s ample for cou n t in g will h ave anappreciab le th iclmes s , an d th e cou n t ig efficien cy will be somewh a timpaired.

Two sys tem s for cou n t in g modera tely th ick Be io sam ples h avebeen described. Th e ea r lier of th ese i6 u ses a th in wsJ l cylin dr ica lcou n ter of th e type described by Su gih a ra , Wolfgan g an d Libby. 46Th e beryllium cou n t in g sample is mou n ted on th e in s ide wsJ ls of twoh em i-cyt iders by depos it ion from a s lu rry of th e sample in a lcoh ol.

Th e h em icy lin d e r s a r e t h en p la ced in close con t a c t w it h t h et h in w all cou n t er . Un d e r t h ese con dit ion s t h e geom etry of th e cou nteris a bou t 40%. To r ed u ce ba ck gr ou n d t h e cou n t e r is su r r ou n d ed by ar t ig of an t i -cot iciden ce cou n ters . Becau se th e sample a rea can bequ ite la rge u n der th ese con dition s th e sample can be made qu ite th in .However, correct ion for s elf-a bsorpt ion of th e rad ia t ion s is n eces sv,a nd m ay be determ in ed by th e method of Su t t le an d Libby. 47

Figu re 7 sh ows an absorpt ion cu rve in polyeth ylen e of th e rad ia t ion sfrom Be 10 i6u sin g su ch a cou nter . The mea su remen t of th e absorp tioncu rve of th e rad ia tion s from a beryllium sample serves a s a ch eckon th e ra dioact ive pu rity of th e sample, an d th e da ta may be u sedto ca lcu la te th e self absorpt ion of th e ra dia t ion s by th e sample,

Eh man n and Koh man 28 h ave recen tly described a cou nt in g procedu refor measu rh qg very low levels of Be io a nd oth er n atu ra lly -occu rr t igr ad ioa ct ive s pecies . Th ey u se a s ide-win dow cou nter h avin g a win dow

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la , Y

z>.* 10-~>G

Io 10 m3040 so 60 70ABSORBER THICKNESS (mq/km&)

Fig. 7 . Absorpt ion cu rve of Bel 0 in

s u rr ou n din g s hield of a nt i-coin cid en ce

p olye t hylen e in close cylin -d r ica l geom e t r y. Da t a ofArn old , referen ce 16.

-1a rea s ligh t ly over 6 cm~, with acou n ters . The sample is placed

SAMPLE TNICKNESS (m@cmt ]

Fig. 8 . Rela t ive cou nt in g r at e p e ru n it w e igh t of sam p le forsamples of Be10 in BeO offixed specific act ivity vs .th e s am ple th ickn es ses .Da t a of Ehm a n n a n d Koh -m an , r efer en ce 28 . Th eext ra pola tion t o ze r ot h ick n e ss w a s m a d e fr omda ta of Nervik an d Steven -son , r efe r en ce 47.

in a d ish close to th e win dow of th ecou n ter h a geometry close to 40Y0. Th is sys tem is ~eren t ly s implerto con s tru ct an d opera te, a lth ou gh cou n t in g samples will gen era lly n otbe qu ite so th in as in th e th in wa ll cou n ter described above. However,s elf s ca t ter t ig in modera tely th in samples h elps to overcome th e effectsof s elf absorpt ion as sh own in Figu re 8 .

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VI. COLLECTION OF DETAILED RADIOCHEMICAL PROCEDURESFOR BERYLLIUM

PROCEDURE i

Sepa ra t ion of beryllium from s ton eSource - W. D. Ehm an n an d T. P:

Acts ~ 340 (i958).

Procedure:sStep 2 .

Y!%@

m ete orite m ater ia lKoh m an , Geoch im .

Rin se th e specimen with aceton e to removemay h ave been u sed to preserve it .

e t C osmoc him .

a n y laqu er wh ich

Grin d a 50-i50 g sample of th e specimen to a fin d powderu s in g an electrolyt ic iron sh eet an d iron roller . Tra n s ferth is fin e powder to a i liter polyeth ylen e beaker wh ich idplaced h a wa terba th a t room tempera tu re.Dis solve th e sample in a hood by t h e cau t iou s a dd it icm of48% hydroflu or ic acid . (Note i) Abou t 5 m l of bydroflu oricacid per gram of sample is u sed. Allow th e m ixtu re tos tan d a t room tempera tu re for 3-4 h ou rs w i th o cc a si on a ls t ir r ir ig .Hea t th e m ixtu re on a wa ter ba th a t i 0 0 C, with occas ion a ls t irr in g, u n t il th e m ixtu re goes ju s t to dryn es s . Add 50 m lof HF to th e res idu e an d aga in evapora te to d ryn es s . Add50 m l con e. HN03 to oxidize iron -d aga in redu ce to dryn es s .Dissolve th e res idu e in iOO m l of con e. HC1 an d aga inevapora te to d ryn es s to remove. excess HF and HNO ~. Repea tth e evapora t ion wit i i 0 0 m l of con e. HC1.Dissolve th e res idu e from th e evapora t ion in i 1 . of 9 -i O MHC1. Filter th rou gh a fu n n el with fr it ted gla s s disk to removet isolu ble res idu e wh ich is u su a lly fou n d in tra ce ~ou n t .Add = accu ra tely kn own amou n t of & ca r r ier to th e solu t ionan d tra n s fer th e solu t ion to a 2 1 . s e,pa ra tory fu rmel.

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.P RocEDu RE 1 (CONTINUED)

Extra ct iron with con secu t ive 300 -400 ml portion s of isopropyleth er wh ich h as been sa t im a ted with 9 M HC1. Th ree of fou r

Step 8.

extract ion a re u su ally su fficien t, Wash th e combin ed eth erextracts th ree t im es with 50 m l port ion s of 9 M HC1, combin ingth e wash ings with th e extracted aqu eou s ph ase.Redu ce th e volume of th e solu t ion to abou t 250 m l on a h ot pla te.To th is solu tion add 500 m l of i2 N HC1, mak tig th e solu tibnapproxima tely 10 M in HC1. Pass th e solu tion th rou gh anion exctige column approxima te ely 2.5 cm in diameter c on ta t iin g200 - 250 ml of Dowex i, X-i O, 100 - 200 mesh ion exchan geres in . Adju s t th e flow ra te to approxima tely 1 m l / m ti. (Note 2 )W&mh th e column with 500 m l of i O M HC1 and combin e th e elu a tes .

!WE!& Redu ce th e volume of th e solu t ion to 300 m l on a h ot pla te.Add NH40H to pH 7 to precipita te Al and Be hydroxides .Filter th rou gh a Millipore HA fflt er in a 6.5 cm Bu ch n er fu n n eland wash with 25 m l of 5% NH4C1 adju s ted to pH 7.

Step 10 . Dissolve th e precip ita te h dilu te HC1 and reprecip ita te an dfilter a s in Step 9. Repea t th e precipita t ion a th ird t im e.

* Tran s fer th e precip ita ted Al and Be h ydroxides on th e filterpaper to a 250 m l beaker . Add 25 m l of 8 M NaOH,and 10-20mg of Fe (~) ca rr ier . Macera te th e filter paper and h ea tth e m&tu re to boilin g. Filter th e warm s lu r ry th rou gh a fu n n el h avin g a 6.5 cm frit ted gla ss disk.

- Wash th e solids in th e fu n n el with a sma ll amou n t of h u t wa ter ,combin in g th e wa sh ings with th e filt ra te. Dilu te th e solu tionto 250 m l with dis t illed wa ter and trea t th e solu t ion with 6 M HC1to precip ita te Al(OH)s and Be(OH)2 a t th e meth yl red en d pofit .

* Filter off th e p recipita te d h ydroxides an d red issolve th em indilu te HC1. Reprecip ita te th e hydroxides with NH40H a t th emeth yl red en d poin t. Filter th e precipita te and aga in repea tth e precipita t ion a t th e meth yl red end pokt .

Step i4. Dissolve th e precip ita ted Al an d Be h ydroxides in th e m in imummoun t of 6 N HC1 nece s s s ry to yield . complete solu tion . Dilu teth e solu tion to approxima tely 50 m l with d is tilled wa ter and


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P R OCE DUR E 1 (CONTINIJ E D)

Step 15 .

Step 16.

Step i7 .

Step i8.

adju s t th e acidity to i. i M HC1 by dropwise add ition of 6 M HC1,u s in g a pH meter an d s tanda rd 1. i M HC1 solu t ion for compa rison .Pass th e solu tion th rou gh a 25 m l res in volume of Dowex 50,X-8 , 50-100 mesh ion exch an ge column abou t i/ 2 in ch hdiameter sn d 10 in . lon g. .4dju s t th e flow ra te to i m l / m in .After th e solu tion h as passed th rou gh th e column elu tion iscon t in u ed with i. i M HC1 u n til Be is completely elu ted ,u su a lly in abou t 6 or 7 res fi volumes . (Note 3)Evapora te th e efflu en t con t t iin g Be to dryn es s on a s teamba th . Dis solve th e res idu e in 25 m l of 2 M HC1. Pass th esolu t ion th rou gh a 5 m l Dowex i ion exch ange column 2 in .lon g an d i/ 2 in . h diameter ., After pas sage of th e samplesolu t ion th e column is wash ed with 10 m l of 2 M HC1 and th e+2wash in g is added to th e firs t elu a te. Pb is adsorbed int he colu m n.Evapora te th e elu a te con ta in in g th e be~llium to dryn es s .Dissolve th e res idu e in 25 m l of O. i M H2C204 - i. 5 M HC1(PH = O. 9). Pass th e resu lt in g solu t ion &ough a Dowex icolumn 4 in . in len gth and i./ 2 in . h d iameter a t a flowra te of i m l/ m in . Con tin u e elu t ion with O. i M H2C04 -0.45 M HC1 u n til 5 res in volumes (abou t 50 m l) of th e elu t in g ~,solu t ion h as passed th rou gh th e column ., Res idu a l Al isadsorbed on th e ,colu mn wh ile berylliu m passes th rou gh .Trea t th e elu a te from th e column with NH40H to pH z 7 top recip it at e Be(OH)2 . Ft iter th e p recipita te on Millipore HAfilter paper in a 6 .5 cm Bu chn er fu n n el, Ign ite th eprecip ita te a t i OOOC, weigh th e BeO to determ in e a ch emica lyield , an d mou n t th e sample for cou n tin g. (Note 4)

Recycle Pr oced u re:- Tran s fer th e BeO from th e cou n t in g tra y to a beaker an d

trea t it with a m ixtu re of 45 m l con e. 13N03 ~d i5 m l9 M H2S04. Boil th e m ixtu re on a h ot pla te fb r i h ou r, or

30


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P ROCE DUR E I (CONTINUED)

Step 2 .

Step 3.

Step 4.

Step 5 ,

St ep 6.

S tep 7.

u n t i l t h e solu t ion is com p le t e . Dilu t e t h e so lu t ion t o iOOm l w it h d is t i lled w a t e r .Ad d a bou t 10 mg Fe (I I I ) ca r r ie r t o t h e solu t ion a n d p r ecip i -t a t e F e (OH)s a n d Be (OH)2 w it h NH40H a t pH ~ 7. F ilt e r t h ep r ecip i t a t e on Wh a cm a n No. 3i filt e r p a p e r in a 6.5 cmBu ch n er fu n ne l.Tr a n sfe r t h e fi lt e r p a p e r a n d h yd r oxid es t o a 250 m l bea k era n d t r ea t w it h i5 m l of 8 M NaOH solu t ion . He a t . t h e so lu t iont o boilin g a n d fi lt e r t h e w a r m slu r r y t h r ou gh a fu n n e l h a vin ga 6.5 cm frit t ed gla s s d isk. Wa sh t h e res idu e with 10 m lof 8 M NaOH add in g t h e w a sh in gs t o t h e filt r a t e .Dilu t e t h e comb in ed so lu t ion s t o iOO m l a n d a d d 6 M HCIt o p r ecip it a t e 13e (O_H)z a t pH w 7. F i lt e r t h is p r ecip it a t eon Millip or e HA fi lt e r p a p e r in a 6.5 cm Bu ch n e r fu n n e l.Dissolve t h e p r ecip it a t e a n d r ep r ecip it a t e tw ice w it h NH40Ha t pH w 7 to as su re remova l of th e Na+ presen t .?lis solve th e fin a l Be(OH} z precip ita te in 25 m l of con e.HC1 an d pass th e solu t ion th rou gh a iO m l Dowex. i an ionexch an ge column 4 in , lon g an d 1/ 2 in . in diam eter . R~mset h e co lu m n w it h 20 m l of con e . HC1 a ft e r in t r od u ct ion oft he sa mp le .Red u ce t h e com b in ed e fflu en t s fr om t h e co lu m n to iO m l byeva p or a t ion on a h o t p la t e . Ad d 20 m l of d is t illed w a t ert o m a k e t h e r e su lt in g so lu t ion a bou t 2 M in HC1. P a sst h is solu t ion t h r ou gh a iO m l Dowex f. colu m n sm d r in set h e colu m n w it h 20 m l of 2 M EW1.Com b in e t h e e fflu en t s fr om t h e co lu m n a n d eva p or a t e t h emt o d ryne s s . Disso lve t h e r e s id u e in 25 m l of O. i M H2C204 -0.45 M HCI a n d p r oceed a s fr om St ep 4.7 in t h e P r oced u r e .(Not e 5).

NOTESi. Violen t e ffe r vescen ce is p r even t ed by t h e u se of t h e w a t e r b a t h for

coolin g a n d t h e s low a d d i t ion of t h e h yd r oflu o r ie a cid .


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P R OCE DUR E l (CONTINUE D)

2. Res idu sl Fe +6 +4 +5 +4 +33 , CO+2 , Cr , U , Pa ,Po, Bi a n d abou t th ~oth er elemen ts a re h eld in th e column (log D> 1); wh ile Ni 2 , Al+3 ,Ca+2, Th+4 , Pb+2, Ra+2 , an d AC+3 of th e elemen ts of in teres t pa s sfreely th rou gh (n o adsorp t ion ). Th e a lka li elemen ts an d th e oth era lka lin e ea r th elemen ts a re s lag n ot a bsorbed.

3 . Al +3 is h eld on th e colu mn , bu t wou ld s ta r t to elu te a t a bou t 12 toi5 res in volumes of i. i M HC1.

4 . It is recommended th a t a du s t ma sk be worn to preven t th e in h a la t ionof very toxic BeO du s t .

5 . Th e ch em ica l p rocedu re as given is n ot completely sa t is fa ctory in as -mu ch a s th e in it ia l ra d ioact ivity u su ally decrea ses on recyclfig.Th e in it ia l ch em ica l yieId sometimes exceeds 100 percen t , in d ica t in gin complete s epa ra t ion from bu lk con st itu en ts , a lth ou gh a givenspecimen of s ton ey meteor ite, m igh t con ta in a ppreciab le amou n ts of*rylUum. It appea rs th a t a t lea s t th ree recycles may be n eces sa ry.to get r id of a ll con tam tit in g act ivit ies a nd in er t im pu r it ies . Th ein trodu ct ion of a n extra ct ion s tep u s in g a ce~laceton e, followin g th ed irect ion s given k Sect ion HI-6; wou ld probably prove of va lu e inelim in a t in g th ese d ifficu lt ies . Su ch an extract ion 8 tep cou ld bein trodu ced a fter s tep i 3 , u s in g an exces s of EDTA to h old back Al,or th e extra ct ion cou ld be ca rr ied ou t followin g Step i 7 a fterp recip ita t in g Be with NE40H.

PROCEDURE 2

Sepa ra t ion of berylliu m from iron m eteorite ma ter ia lSource - W. D. Ehmam I an d T. P. Kohman , Geoch im et Cosmoch im .

Acts ~ 340 (1958).Procedure:s tep i. Wa sh th e sample, wh ich m ay weigh from iOO to 150 g, with

d is t illed wa ter an d a ceton e to remove ter re sk id d ir ta nd an y la cqu er wh ich m ay h ave been u sed to preserve th especimen.

32


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P RocE Du RE ,2 (CONTINUED)

Step 2 .

S!!?EQ

Step 4.

! &J&

Place th e sample in a 21. beaker a n d trea t with con secu t ive.200 m l por t ion s of aqu a regia . After rea ct ion h a~ ceasedpou r off each port ion in to a sepa ra te beaker . Con t in u e th ist rea tmen t u nt il th e specimen is com pletely dis solved.To th e combin ed solu t ion s add 25 m l of con e. HNO ~ t o en su reoxida tion of iron (H). Evapora te th e solu t ion to n ea r d&n ess.,with severa l 500 m l port ion s of con e. HC1 to remove excessHN03.To th e sm s ll volume from th e la s t evapora t ion add su fficien t9 M HC1 to br in g th e volume u p to i 1 . Filter th e solu tionth rou gh a Wha trn an No. 50 fUter paper in a Bu ch n er fu n n eLA small res idu e, pos s ibly gra ph ite, m ay be d is ca ded .Add beryllium ca r r ier an d ca r r ier s for oth er ra d ioelemen tswh ich it m ay be des ired to sepa ra te. Tra n s fer t ie solu t ionto a 21. s epa ra tor fu n n el an d extract iron with con secu t ive300-400 m l por t ion s of isopropyl eth er s a tu ra ted with 9 M HC1.Th ree or fou r extra ct ion s a re u su ally su fficien t .Combtie th e eth er layers a n d wa sh th em th ree t im es with50 m l por t ion s of 9 M HC1, Add th ese wash in gs to th e aqu eou sphase . Proceed a s from Step 8 of Procedu re 1 for s epa ra t in gberylliu m from s ton e meteor ite m a ter ia l. (Notes 1 , 2 ).

NOTES1 . Th e ch em ica l yield of beryllium $omett ies appea rs to exceed iOO per

cen t . However , th e weigh t of BeO often decrea ses apprecia bly onrecyclin g; imply~g th a t th e a ppa ren t extra yield corn ea fromticom plete s epa ra t ion from bu lk con s t itu en ts ra th er th a n fromberylliu m presen t in th e m eteorite.

2 . See Note 5 of Procedu re S .


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PROCEDURE 3Sep a r at ion of b e r ylliu m fr om d e .ep -sea sed im en ts (I ).Sou r ce - P . S . Goe l, D. P . Kh a r k a r , D. La l, N. Na r sa p p a ya , B.

P et e r s , a n d V. Ya t i r a jam , Deep -sea Resea r ch 4_, 202 (1957).Cor e sam p le s of ocea n -bot t om sed im en t s w e igh ed be tw een 66 a n d

i 39 gr am s w h en d r y. Be r y llium w a s r ecove r ed fr om th em w it h ou ta d d i t ion of b e r yllium ca r r ie r by t h e follow in g p r oced u r e . Th e r ecove r ye ff i c ien t y w a s d e t e r m in ed t o be 80 & i 0~0 by sp ik in g som e sam p le

7se d im en t s w it h Be t r a ce r b e for e t h e a n a lys is .P r o c e d u r e :St ep i. TO t h e d r y sam p le a d d 500 m l con e . HC1 a n d 250 m l con e .

HNO ~. H ea t t o d es t r oy or ga n ic m a t t e r a n d t o d r ive offt h e a cid . Des t r oy n i t r a t e s by r ep ea t ed eva p or a t ion w it hcon e. HC1.

S tep 2 . Boil t h e sem i-d r y r e s id u e fo r i5-2CI m in . w it h con e . HC1,d ilu t e w it h 300 m l w a t e r a n d h ea t t h e m ix t u r e t o b oilin g.Allow t h e solid s t o se t t le a n d d e ca n t t h e so lu t ion . Wa sht h e so lid r e~j~d u e w it h 100 m l p or t ion s of 6 N HC!l u n t ilfr ee of ir on . Com b in e t h e so lu t ion s (Solu t ion L).

S t ep 3. Boil t h e so lid r e s id u e w it h i20 g NaOH in a gla ze d s ilicad ish for i 5 m i.n a n d filt e r off a n y u n d isso lved so lid(Solu t ion M). F u se t h e so lid r e s id u e w it h five t im es it sw e igh t of Na 2C03 a n d d isso lve t h e m e lt in 100-i50 m lof w a t e r . F ilt e r off a n d d isca r d a n y in so lu b le r e s id u e(S olu t io n N ).

S t ep 4. Com b in e solu t ion s L, M a n d N a n d h e a t t o d r ive off (202.Ad d am mon ia t o pH 8 t o p r ecip it a t e in solu ble h yd r oxid es .F ilt e r t h e m ix t u r e , d isca r d in g t h e filt r a t e . Dissolve t h ep r ecip it a t e in 200 m l con e . HC1.

S t e p 5. Eva p or a t e t h e solu t ion t o d r yn ess tw ice w it h a d d it ion s ofHC1 t o p r ecip i t a t e s ilica . Boi l t h e p r ecip it a t e w it h400 m l of 6 N HC1 a n d filt e r (So lu t ion O).

S t ep 6. Mois t en t h e s ilica r e s id u e w it h H2S04 a n d h ea t w it h 487.HF to r em ove Si02. F u me a n y r em ain in g r es id u e w it h H2S04,ign it e it a n d t h en fu se i t w it h Na 2C0s . Disso lve t h e m e lt

34


40/63

Y!3z

Step 8.

Step i2 .

Step 13.

P RocEDu RE 3 (CONT~UED)

in HC1 an d filter . Combin e th e filt ra te with Solu tion O.Add ammon ia to Solu t ion O to br in g th e pH to 8 . Filter th ep recipita ted h ydroxides and dis ca rd th e filt ra te. Dissolveth e precip ita te in .500 m l 6 N HC1.Extra ct Fe(III) from th e solu t ion by sh ak@ with i lit erof eth er . Con cen tra te th e aqu eou e ph ase to i50 m l, add15 g NH4C1 a n d cool in a n ice b a t h . Ad d 300 m l of e t h e ran d pass in HC1 gas . F~ter off th e precipita te of Al an dTi ch lo rid es . Evapora te th e filt r a te to 50 m l volume.Add 8 g d iso~um EDTA to th e solu t ion ah d ad ju s t th e pHto 4 . 5-5.0 by th e add ition of dilu te ~40H. Add 2.5 m lacetyla ce,ton e an d sh ake. for 5 m tiu tes .Extra ct beryllium from solu tion with fou r i 00 m l por tion sof ben zene, sh ak in g th e m ixtu re for i O mhm tes each t im e.,, ,.Combin e th e ben zen e layers and back-ex@act berylliu mby sh ak in g with fou r 475 m l p or t ion s , of 6 N HC1.Combin e th e HC1 extracts and evapora te th e solu t ion todryness . Des troy a Iy, organ ic ma tter by evapora t ion witha~,a regia . Take u p th e res idu e from th e evapora t ion inabou t 40 m l of i N HC1.Cool we solu t ion t i an ice ba th an d add iO m l of 67. cu pferrons olu t ion . Extra ct th e ret ire with th ree 40-m l por tion s ofCHC13, a nd dis ca rd th e organ ic ph ase. Evapora te th eaqu eou s phase to dryn es s an d decompose organ ic m a~erby evapora tion with HN03.Decompose res idu a l n it ra tes by boilin g th e res idu e withHC!l. Evapora te th e solu t ion to dryn es s and take u p th eres idu e in 5 m l of d ilu te HC1. Tra n s fer th e solu t ion a lit t lea t a t im e to a p la s t ic cou n t in g d ish an d evapora te to d ryn es su n der a h ea t lamp .


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PROCEDURE 4Sepa ra tion of berylliu m from deep-s ea sed imen ts (II).Sou rce. - P. S. Goel, D. P. Kh a rka r , D. La l, N. Na rsa ppaya ; B.

Peter s , an d V. Ya tira jam , Deep-s ea Resea rch ~ 202 (i957).A s implified procedu re for recoverin g Be 10 from samples of ocean -

bottom sed imen ts , a s sum in g th a t th e @ryllium is adsorbed on th esu r face of th e. c la y pmicles . ,Procedure:

Step 2.

Step 4.

Step 5 .

Step 6.

Add 5 mg of BeO to th e dried sample an d h ea t th e sample to500C in a mu ffle fu rn ace for 2 hou rs to des troy organ icmatier .Leach t ie ign ited ma ter ia l 4 tim es with i90 m l of con e. HC1an d th en wa sh th e in solu ble res idu e with i: i HC1 solu t ion u nt il th e wa sh in gs a re colorless .Combin e th e acid leach and wash ing6 an d evapora te th esolu t ion to sma ll volume. (Note i) Take u p th e res idu ein wa ter an d add 400 g of disodiu rn EDTA. Adju s t th ePH. of th e solu tion to 4.5 - 5 .Add 5 ml a ce~laceton e an d shake for 5 m inu tes . Th enextract the solu tion with fou r port ion s of ben zen e, sh akin gth e m ixtu re for i O m in u tes each t im e.Wash th e combin ed benzene extra cts with wa ter a t pH 5 .Disc=d th e wa sh in gs and back extract berylliu m withfou r port ion s of 6 N HC1.Tra&fer th e solu t ion a lit t le a t a t im e to a pla s tic cou n t in gd ish an d evapora te to d ryn es s u nder a h ea t l=p . (Note 2)

NOTES,Th e procedu re as qu oted in th e orig&l a rt icle s t ites th a t ana ce~laceton e -ben zen e, extract ion is ca rr ied ou t d irect ly on th eHC1 solu t ion a fter th e &sodium EDTA ha s been added . Sin ce th eextra ction with acetylaceton e mu st be ca rr ied ou t from solu tion sof pH grea ter th a n 4.5, th e con s iderab le qu t it ity of base wh ichwou ld be n e.e de d to brin g th e s t r~gly acid solu tion to th e proper

38


42/63

P R OCE DUR E 4 (CONTINUE D)

pH wou ld re su it in a very la rge volume of solu t ion to be extra cted .Th e detd ls of th e procedu re from th is poin t onward a re n ot givenin th e or igin a l a r t icle. Steps 3 , 4 an d 5 represen t an a t tempta t givin g specific deta ils of th e procedu re based u pon in forma tiongiven in th e origin al a r t icle.

2. Itrema in s to be demons tra ted to wh a t exten t th is s t ip lifiedioprocedu re is capable of recoverin g Be from samples of

s ed im en ta ry m at er ia l.

Pt iEDURE 5Sepa ra t ion of beryllium from Clay by a solven t extra ct ion procedu re.Source - J . R. Merrill, M. Hon da , and J . R. Arn old ,

(t o b e p u blis h ed ).Procedure:

Step 2.

S.!zI+

Divide th e clay sample in to ca . 100 g u n its . Dispers e eachof th em . in a s rn s ll amou n t of wa ter in a i lit er , h ea t-res is tan t polyeth ylen e beaker . To th e m ixtu re s lowly add250 g of 48~, HF foIlowed by 80 m l of con cen tra ted H2S04.Add abou t i O mg of berylUum car rier to th e m ixtu re.Trsn s fer th e m ixtu re to a 300 m l p la t in um dish an d h ea t verys lowly over a sma ll ga s flame . Con tin u e hea t- u n tfl th evis cou s solu t ion wh ich rema in s begin s to solid ify. Coolt h e m ixt u re.Hea t th e res idu e with 300 m l of wa ter . Cen trHu ge an yu nd issolved ma teria l, wh ich shou ld con s is t m a in ly of b lackorgan ic ma tter an d a lum in um an d ca lcium su lfa tes (Note 4).If mu ch u n a t tach ed origin a l s ample is p res en t fu r th erbisu lfa te t rea tmen t is n ecess a ry. Combin e th e su pern a ta n tsolu tion s from th e severa l cla y u n its (Note 2 ).To th e combtied solu t ion s add EDTA in abou t 20% excessover th e amou n t es tim a ted for complet in g th e Fe and Alpresen t . Add su fficien t wa ter to br in g th e volume of th esolu tion to abou t 3 liter s .

37


43/63

P RocEDu RE 5 (CONTINTJ ED)

Step 5 .

Step 6.

Sten 8 .

Step 9.

-

Adju s t th e pH with ammon ia to abou t 6.4 (Note 3 ). Wh enth e solu tion becomes cool aga in add 25 m l bf ace~la ceton ean d s tfi u n t il it is dis solved. Tran s fer th e solu t ion toa large s epa ra tor fu n n el an d e-act th e beryllium complexwi t l r t h r e e 250 m l port ion s of ben zen e (Note 4).Combin e th e ben zen e extracts an d wash th em with 500 m l ofwa ter bu ffered to pH 5-6 with dilu te aceta te. Dis ca rd th ea qu eou s la yer . Back-extract berylliu m from th e ben zen esolution w it h two i 50 m l por tion s of 6 M HC1.Combin e t ie HC1 extracts and add 45 g of disodium EDTA anden ou gh ammon ia to b rin g th e pH to 6.4. Allow th e solu tionto cool, th en add i O m l of acetylaceton e an d s t ir u n t il it isdissolved. Tran s fer th e solu t ion to a Sepa ra tor fu n u el an dextract with th ree i 00 m l portion s of benzen e.Combin e th e ben zen e extracts , an d a fter wa sh in g with 200 m lof bu ffered wa ter , back-extra ct beryllium with two 50 m lport ion s of 6 N HC1. Combin e th e HC1 extra cts h a la rgebeaker , add i O m l of con e. HNO ~ and h ea t th e Rolu t ion(ca u tion ! ). Boil th e solu t ion n ea rly to dryn es s withrepea ted addit ion s of HNOs . ~ . .Take u p th e res idu e from th e evapora t ion in wa ter an d addammon ia to b r in g th e pH to 8 . Filter th e p recipita ted BS(OH)2an d ign ite to BeO.Weigh th e BeO to determ in e ch em ica l yield and mou n t forcou ntfig (Note 5).

,,NOTES

i. In a p relim in a ry exp er im en t, a Stock ton sh a le s ample was u sed asa -model an d Be 7 tra cer was u sed to measu re th e recovery of beryllium .Wi~ abou t 10 mg of beryllium ca rr ier it was fou n d th a t th e h ot wa tere*acts of t he su lfa te cake con ta in a lm os t a ll of th e, berylliu mwh ereas 70 -80~0 of tota l a lum inum was left in solid form .

2 . Sometimes th e brown su pern a tan t solu tion con ta in s some su spen fi ion(a lu minu m compou nd).


44/63

P RocEDu RE 5 (CONTINUED)

3.4.

5 .

Th e color of th e iron - EDTA complex is u sefu l a g an in d ica tor .Occas ion a l d ifficu lt ies of s epa ra t ion requ ire cen tr ifu gin g th e organ icla yer a t th is s tep .Th e over -~ yield of beryllium is abou t 60-70%. Th e procedu re h a sbeen su fficien t to remove a ll rad ioact ive impu rit ies from th e claysamples wh ich were an a lysed , bu t berylliu m ca r r ier is n eces s a ryfor good res ults .

PROCEDURE 6Sepa ra t ion of beryllium from cla y by ~ ion exch an ge procedu re.Sou r ce - J ,

Procedure:Steps i-3

Step 4 .

Ste.u 5 .

Step 7 .

W,?&

R. MerrUl, M. Hon da , a n d J . R. Arn old , (to be pu b lish ed).

As k Procedu re 5 , u s in g 20 mg of BeO ca r r ier for a200-300 g cla y sam ple.T&e O. 5 m l of th e combtied aqu eou s extracts of th e su lfa teca ke an d an a lyse by EDTA complexiometr ic t it r a t ion forFe an d Al (Note i).Add grdudly a mMxre of 2 H4Y + i Na2H2Y* 2 H20 +5 CaC03 to th e solu t ion u n t il abou t O. i mole of exces s EDTA,over th a t n eeded to complex Fe an d Al, MS ken added.Adju s t th e pH to 3.5 -4 with more CaC03 (u su a lly abou t iOO g).(Note 2 ).Add 60 m l of glacia l acet ic a cid as a bu ffer (Note 3 ).Filter off th e in solu ble CaS04 - CaCO ~ an d dflu te th efilt r a te an d wa sh in gs to iO liter s .Pass th e solu t ion th rou gh a i ~ter Dowex 50 x 8 ionexch an ge column in th e Sod ium form . Mter th is solu t ionh a s pas sed th ou gh , pas s th rou gh 1 liter of O. Oi M EDTA +O. i M NaAc + O. 5 M HAc to rem ove an y tra ces of Al a n d Mna dsorbed on th e COILUIUI. (No* 4).Elu te beryllium from th e column with a solu tion of O. 5 MNaAc an d 1 M HAc. Abou t 0 . 5-4 .5 column volum es ofefflu en t con tdn a ll th e berylliu m.

39


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P ROCED~E 6 (CONTINUED)

EsE& Precipita te Be(OH)Z from th e efflu en t by th e addition of

i.

2.

3.

4.

ammon ia . Filter th e p recipita te an d ign ite to. B@. Weighto determ in e ch em ica l yield a nd mou n t for cou n tin g.

NOTESFor d iscu ss ion s of complexometr ic t it ra t ion see G. Schwarzen ba ch ,h a lys t 80 , 713 (4955); die Komplexometr is ch e Titra t ion , G.Sch ws rzen ba ch , F. En ke, W@tga rt ( i955); Com plexometr icTit ra t ion s, G. Schwarzen ba ch an d H. Irvin g, Meth u en an d Co. Ltd . ,Lon don , In ter s cien ce Pu blish ers , In c. , New York. ( i95 7).Ca lcium ca rbon a te is u sed to ra is e th e pH so th a t we electro-lyte con cen tra t ion w~ not be in crea sed . Beryllium is n otcopercip ita ted with Ca S04.If appreciable &ou n ts of Mg or Ca a re in solu t ion th ey willrep lace Na+ from th e ion exchmge resin u sed in th e su cceedin gs tep . In th e presen ce of exces s EDTA th is in crea ses th e pH ofth e solu tion , th e most impor tan t va ria ble in th e proces s . To preven

The Radio Chemistry of Beryllium.us AEC

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