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A critical study of the methods for the quantitative determination of beryllium

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A critical study of the methods for the quantitative determination of beryllium

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Content A CRITICAL STUDY OF THE M ETHODS
FOR THE
QUANTITATIVE DSTERMIB ATI O H OF BERYLLIUM
A T h esis
P re se n te d t o th e D epartm ent of C hem istry
U n iv e rs ity of S outhern C a lif o r n ia
In P a r t i a l F u lfillm e n t
o f th e
R equirem ents f o r th e
Degree of M aster o f A rts
by
W . Roy Hews cm
June 1935
UMI Number: EP41469
. All rights reserved
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0 5 s w « « W biistteg" .. ’
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jetary
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INTRODUCTION
The in c re a s in g im portance o f b e ry lliu m and
b e ry lliu m a llo y s in in d u s try h as le d th e s c i e n t i f i c
w orld t o seek more a c c u ra te and more r e l i a b l e m ethods
f o r th e q u a n tita tiv e d e te rm in a tio n of b e ry lliu m .
A lthough th e re a re s e v e r a l m ethods a v a ila b le , th e
ac cu rac y o f th e r e s u l t s o b ta in e d by u sin g th e s e
m ethods i s somewhat q u e s tio n a b le . From th e l i t e r a t u r e
on th e s u b je c t we f in d th a t th e problem is th e so u rce
of much d i f f i c u l t y , c h ie f ly because of th e b u lk y and
g e la tin o u s n a tu re o f th e h ydroxide p r e c i p i t a t e s of
b e ry lliu m , aluminum and ir o n . T his p a r t i c u l a r k in d
of p r e c i p i t a t e p o sse sse s th e p ro p e rty of r e a d i ly ad-*
so rb in g s u b sta n c e s from s o lu tio n th e re b y m aking th e
m ethods in v o lv in g such p r e c i p it a t i o n s r a t h e r d i f f i c u l t
to make q u a n t i t a t i v e .
An en u m eratio n o f th e m ethods d e s c rib e d in
l i t e r a t u r e w i l l se rv e to show th e e x te n t o f th e work
which has been done on th e a n a ly ti c a l d e te rm in a tio n
of b e ry lliu m . H ubert T. S. B r itto n 1 h a s g iv en a
resum e of t h ir t e e n m ethods d e s c rib e d in th e l i t e r a
tu r e from 1798 to 1914.
1 H ubert T. S. B r itto n , A n a ly st, 46, 359-66 (1921)
2.
1 . D ig e s tin g o f th e h y d ro x id e p r e c i p i t a t e s
w ith c o n c e n tra te d s o lu tio n s of ammonium c a rb o n a te
Q ausing b e ry lliu m h y d ro x id e t o p a ss in to s o lu tio n .
(Y au q u elln 2 ) .
2 . T reatm ent of aluminum and b e ry lliu m
h y d ro x id es w ith a s a tu r a te d s o lu tio n o f ammonium
c h lo rid e and b o ile d u n t i l a l l f r e e ammonia h as been
l i b e r a t e d , th e b e ry lliu m h y d ro x id e p a s s in g in to
s o lu tio n . (B. H. Rose3 ) .
3 . The d ecom position of e i t h e r sodium hydroxide
o r p o tassiu m h y d ro x id e s o lu tio n s o f b e ry lliu m
h y d ro x id e when d ilu t e d and b o ile d . (G m elin4 ) .
4 . S o lu b ili ty o f b o th b e ry lliu m and aluminum
h y d ro x id e in e i t h e r su lp h u ro u s a c id o r in a concen
t r a t e d s o lu tio n o f ammonium h y d ro x id e s a tu r a te d w ith
s u lp h u r d io x id e . When th e s o lu tio n i s b o ile d to
e x p e l th e s u lp h u r d io x id e , th e aluminum h y d ro x id e i s
p r e c i p i t a t e d , w h ile th e b e ry lliu m s ta y s in s o lu tio n .
(B e r th e ir 5 ) *
2 V au g u elin , Ann. Chim. P h y s ., 26. 155 (1798)
3 B. H. Rose, Kandbuoh d e r A n a ly tisch e n Chemie, I I , £>1, (1851)
4 Gm elin, Pogg A nnalen, 50, 175, (1840)
5 B e r th ie r , Ann. Chim. P h y s ., i i i 7, 74, (1843)
A s im ila r method h as been d e s c rib e d u sin g
sodium th io s u lp h a t e .6
5 . The p r e c i p i t a t i o n o f aluminum a s a b a s ic
su lp h a te by th e a d d itio n o f sin e to a s o lu tio n in
s u lp h u ric a c id . (D ebray7 ) .
To be s a t i s f a c t o r y , t h i s m ethod re q u ire d a
d ig e s tio n w ith z in c f o r two o r th r e e d ay s.
6 . A m ethod in w hich th e o x id es a re fu se d
w ith p o tassiu m , hydrogen f lu o r id e th e n tr e a te d w ith
b o ilin g w a te r and th e b e ry lliu m e x tr a c te d as a
double f lu o r id e by th e a d d itio n of hydrogen f lu o r id e
7 . A p r e c i p i t a t i o n o f b e ry lliu m as a double
p h o sp h ate by th e a d d itio n of ammonium p hosphate
in th e p rese n ce of c i t r i c a c id when th e q u a n tity
o f aluminum p r e s e n t i s s m a ll, (H b ssle r9 ) .
8 . A method depending upon th e i n s o l u b i l i t y of
b e ry lliu m h ydroxide in d im ethylam ine. (V in cen t1 0 ) .
6 Gomptes r e n d ., 46, 987, (1858)
7 D ebray, Ann. Chim. P h y s ., i i i , 44, (1855)
8 S i l l . Amer. J . S c i ., 34, 356, (1864)
9 K b ssle r, Z e its c h , A nal. Chem., 17, 148 (1878)
10 V in cen t, B u ll. Soc. Chim ., 3 3 , 157, (1880)
9 . H aven's m ethod depends upon th e in
s o l u b i l i t y of AlClg 6HgO in o o n o e n tra te d hy d ro -
o h lo r ic a o id and e t h e r s a tu r a te d w ith hydrogen
c h lo rid e g a s .
10. S o lu b ili ty of b a s ic b e ry lliu m a c e ta te
in ch lo ro fo rm . (Haber and Van O ordt12) .
11. P r e c i p i t a t i o n of th e aluminum by s o lu tio n
of sodium c a rb o n a te . (H art1 3 ) .
T his m ethod was l a t e r m o d ifie d by P arso n s and
1 4
B arnes w ith th e u se o f sodium b ic arb o n ate *
IE . The fu s io n o f b e ry lliu m oxide and aluminum
oxide w ith e x c ess sodium ca rb o n a te f o r two o r th r e e
h o u rs , and th e e x tr a c tio n o f th e sodium alu m in a te
w ith w a te r, th e b e ry lliu m oxide rem ain in g u n a tta c h e d .
(W inder and Wenger1 5 ) .
13. The m ethod depending upon th e v o l a t i l i t y
of b a s ic b e ry lliu m a c e ta te by d i s t i l l a t i o n u n d er
16,
reduoed p re s s u re * (19 mm.)
11 Haven, Chem. News, 76, 111, (1897)
IE H aber and Van O ordt, Z e its c h . A norg. Chem., 40 , 466, (1903)
13 H a rt, J . Amer. Chem. S o c ., 17, 604, (1896)
14 P arso n s and B arn es, J . Amer* Chem. S o c ., 28, 1589, (1906)
15 W inder and Wenger, Z e its c h . A nal. Chim ., 51, 470, (1912)
16 B u ll. Soc. Chim ., 15, E05, (1914)
In a d d itio n to th e s e , we f in d th e fo llo w in g
in th e l a t e r l i t e r a t u r e .
14. The use o f q u in a liz a r in o r 1 , 2, 5 , 8
te tra h y d ro x y a n th ra q u in o n e in an a lk a lin e s o lu tio n
p r e o i p i t a t e s b e ry lliu m w hich form s a b lu e la k e and
i s d eterm in ed o o lo r im e tr ic a lly . (Helmut F is c h e r^ 7 ) .
15. The s e p a ra tio n of aluminum from a s o lu tio n
o f aluminum and b e ry lliu m by th e a d d itio n of oxine
o r 8 -h y d ro x y q u in o lin e . (Hoi th o ff and S a n d e ll^ 8 ) ,
16. M o d ific a tio n of e t h e r h y d ro c h lo ric a c id
method o f rem oving th e aluminum. (C h u rc h ill,
19
B rid g es and Lee ) .
17. S e p a ra tio n o f b e ry lliu m from la rg e
q u a n t i t i e s of ir o n , th e d eterm in atio n of b e ry lliu m
in cop p er, n ic k e l and zin c a llo y s and th e d e te rm in a
tio n of b e ry lliu m in b e r y l. (Helmut F is c h e r 2®).
18 . The s e p a r a tio n of b e ry lliu m from aluminum
by th e use o f g u an id in e c a rb o n a te . ( J l l e k and K ota2^ ) .
17 Helmut F is c h e r, W iss. V erftff. S'.iem ens-Eonzera,
5, 99-119 (1926)
18 E o lth o ff and S a n d e ll, J . Am. Chem. S o c ., 5 0 . 1900
19 C h u rc h ill, B rid g es and L ee, In d . Eng. Chem. A nal. Ed.
2, 405-7, (1930)
20 Helmut F is c h e r, (Loc. o i t . ) 8 (1) 9 -2 0 , (1929)
21 J i l e k and K ota, C .A ., 25, 5864, (1931)
RESUM E OF ANALYTICAL W O R K WITH SPECIAL
ATTENTION TO W O R K O N COM PARISON OF M ETHODS
By th e p o s itio n of b e ry lliu m a s th e f i r s t
member of group I I in th e p e r io d ic system , we may
p r e d ic t some o f i t s p r o p e r tie s and a c tio n s*
I I I I I I
r ?
Li Be B C
Na M g A1 S i
B e ry lliu m a s a m e ta l i s s l i g h t l y l e s s b a s ic
in c h a r a c te r th a n i s magnesium b u t in i t s a c tio n s
resem b les aluminum v ery c lo s e ly . T his we f in d tr u e
of th e f i r s t member of any group and th e second
member of th e n e x t group such as th e resem blance of
boron to s i l i c o n . The hy d ro x id e o f b e ry lliu m i s a
m o d erately weak b ase which p o s s e s s e s s l i g h t a c id
p r o p e r tie s a s does aluminum h y d ro x id e . Aluminum,
how ever, p o s s e s s e s s tr o n g e r am photeric p r o p e r tie s
th a n does b e ry lliu m and th e r e f o r e is more t r u l y a
t r a n s i t i o n elem en t. I t i s a ls o s l i g h t l y more a c id ic .
Upon th e d if fe re n c e in th e a c i d i t y o f th e h y d ro x id e
of aluminum and b e ry lliu m a re b ased many q u a n tita
ti v e d e te rm in a tio n s ; such as -
1 . D ig e s tio n of th e h y d ro x id es w ith cancan-
t r a t e d amonium ca rb o n a te c a u sin g b e ry lliu m to p a ss
in to s o lu t io n ,
2 . D ig e stio n of th e h y d ro x id es w ith s a tu r a te d
s o lu tio n s of ammonium c h lo rid e and b o ilin g u n t i l a l l
f r e e ammonia is l i b e r a t e d ,
3 . D ecom position of sodium hy d ro x id e or
p o ta ssiu m hy d ro x id e s o lu tio n s o f b e ry lliu m h y d ro x id e
by d i l u t in g and b o ilin g .
4 , S o lu b ili ty of b o th b e ry lliu m and aluminum
h y d ro x id e in su lp h u ro u s a c id and th e p r e c i p i t a t i o n
o f aluminum hydroxide when th e s o lu tio n i s b o ile d
to e x p e l su lp h u r d io x id e ,
5 , The use of sodium c a rb o n a te o r sodium
b ic a rb o n a te .
These m ethods depend upon th e fo rm a tio n o f
s o lu b le b a s ic s a l t s by b e ry lliu m le a v in g th e aluminum
22
p r e c i p i t a t e d , H ild eb ran d * found t h a t th e hydrogen
io n c o n c e n tra tio n n e c e s s a ry to p r e c i p i t a t e b e ry lliu m
and aluminum h y d ro x id es by means of sodium h y d ro x id e
v a r ie d from 10“3 to 10“® r e s p e c tiv e ly . T h e re fo re ,
i t may be seen t h a t th e s e p a ra tio n s depending upon
th e fo rm a tio n o f s o lu b le b a s ic s a l t s of b e ry lliu m
m ust be k e p t a t a d e f in ite hydrogen io n c o n c e n tra tio n
22 H ild e b ra n d , J . Amer. Chem. S o c ., 35, 864, (1913)
by th e use of th e r e a g e n ts . T h e re fo re , th e concen
t r a t i o n s and te m p e ra tu re s of th e re a g e n ts m ust be
c a r e f u l ly r e g u la te d .
On th e su rfa o e i t lo o k s as i f th e c o n o e n tra tio n
oou ld be re g u la te d w ith s u f f i c i e n t accu racy and com
p le te s e p a r a tio n co u ld th e re b y be e f f e c t e d . However,
th e n a tu re of th e c o l lo id a l p r e c i p i t a t e s of th e
h y d ro x id es of ir o n , aluminum and b e ry lliu m re n d e rs
th e s e p a ra tio n s a l i t t l e in a c c u r a te . The p r e c i p i t a t e
has a g r e a t ten d en cy to ad so rb su b sta n c e s from
s o lu tio n . T h e re fo re , in th e s e m ethods, th e o b je c t to
s t r i v e f o r i s th e re d u c tio n in seme m anner of th e
volum inous p r e o i p i t a t e to a form in w hich i t may be
e a s i l y and q u ic k ly washed f r e e from ad so rb ed m a te r ia l.
The b e ry lliu m h ydroxide o b ta in e d by b o ilin g w ith
p o ta ssiu m hydroxide s o lu tio n was found, to be g ra n u la r
and co u ld be e a s ily w ashed, th e a d s o rp tio n seem ing
to be a t a minimum. Some a u t h o r i t i e s have o b ta in e d
good r e s u l t s by th e u se of t h i s m ethod and some have
23
n o t. B tltto n g iv e s th e m ost fa v o ra b le c o n d itio n s
f o r th e u se of sodium h y d ro x id e .
1 . E v ap o rate s o lu tio n to 25 m l. b rin g to room
te m p e ra tu re .
23 B r itto n , A n a ly st, 46, 359-366, (1921)
2 . Add 6 S T sodium hy d ro x id e u n t i l th e p r e c i p i
t a t e j u s t r e d is s o lv e s . Too much w i l l oause a slo w er
and Incom plete d e p o s itio n of b e ry lliu m h y d ro x id e .
3 . B o il f o r t y m inutes and d i l u t e to 500 ml#
Too lo n g b o ilin g may cause d e p o s itio n of aluminum
h y d ro x id e.
4 . F i l t e r th e b e ry lliu m hy d ro x id e im m ediately*
f o r i f allow ed to s ta n d , th e sodium alu m in ate w i l l
slo w ly decompose and a ls o some b e ry lliu m hy d ro x id e
may be d is s o lv e d .
He gave r e s u l t s a s fo llo w s :
Grams BeO ta k e n Grams BeO found
0.206? 0.2065
0.1255 0.1258
0,0665 0.0665
0.0653 0.0658
Some have o b ta in e d s a t i s f a c t o r y r e s u l t s w ith
th e ammonium c a rb o n a te m ethod, b u t th e account g iv en
by B r itto n ^ 4 i s n o t com plim entary to th e m ethod.
The a d d itio n of th e re a g e n t to a c o ld s o lu tio n
o f b e ry lliu m and aluminum s a l t s , dropw ise w ith con
s t a n t s t i r r i n g in o rd e r t o e lim in a te a d s o rp tio n as
much as p o s s ib le was t r i e d . The c o n c e n tra tio n s and
4.
24 B r itto n ,( L o c . c i t . )
te m p e ra tu re s were v aried , and i t was found t h a t th e
amount o f b e ry lliu m c a r r ie d down by th e p r e c i p i t a t e d
aluminum was a p p re c ia b le no m a tte r how th e p ro c e s s
was c a r r ie d o u t. B r itto n th e n t e s t e d th e f i l t r a t e
w hich sh o u ld have c o n ta in e d n o th in g b u t b e ry lliu m
which had n o t been occluded by th e aluminum hy d ro x id e
and found a f t e r tre a tm e n t t h a t c r y s t a l s o f alum were
form ed w hich pro v ed th a t th e r e was a ls o some aluminum
which had n o t been p r e c i p i t a t e d .
The ammonium s u lp h ite m ethod depends upon th e
c o n c e n tra tio n of hydrogen io n s produced in a weak
s o lu tio n of su lp h u ro u s a c id from which no more su lp h u r
d io x id e can be e x p e lle d by b o ili n g . I t i s claim ed
t h a t th e hydrogen io n c o n c e n tra tio n th u s o b ta in e d i s
cap ab le of k eep in g th e b e ry lliu m h y d ro x id e in s o lu tio n
b u t w i l l n o t d is s o lv e th e aluminum h y d ro x id e .
B r i t t o n 's r e s u l t s show t h a t c o n s id e ra b le amounts
of b e ry lliu m a re ad so rb ed by th e aluminum h y d ro x id e .
Grams AlgOg ta k en Grams AlgOg found
0.1695 0.1811
0.0766 0,0911
A ll th e aluminum a p p e a rs t o have been p r e c i p i-
I
ta te d b u t a ls o sane b e ry lliu m was c a r r ie d down alo n g
w ith th e p r e c i p i t a t i o n .
She method of u s in g sodium c a rb o n a te w hich ten d s
to p r e c i p i t a t e aluminum and le a v e b e ry lliu m in s o lu tio n
does n o t work out w e ll, because of th e f a c t th a t
sodium c a rb o n a te i s much to o b a s ic in i t s r e a c tio n s
and te n d s t o d is s o lv e a p p re c ia b le amounts o f aluminum
h y d ro x id e •
The s e p a ra tio n o f b e ry lliu m from aluminum by
th e use of th e sodium b ic a rb o n a te (P arso n s and B arnes
PR
m ethod ) , sh o u ld t h e o r e t i c a l l y approach a b e t t e r
s e p a r a tio n s in c e t h i s re a g e n t h y d r o liz e s to form a
l e s s b a s ic s o lu tio n th an does sodium c a rb o n a te .
The s o lu tio n of b e ry lliu m h y d ro x id e in sodium b ic a rb *
onate ta k e s p la c e much more r e a d ily on warm ing,
th e re fo r e i t i s su g g e sted in th e p ro ced u re t o b o il
f o r one m in u te . Too much b o ilin g , how ever, would
cau se th e lo s s of an e x c e ss amount of carbon d io x id e
w hich would d is p la c e th e h y d ro ly s is e q u ilib riu m o f
sodium b ic a rb o n a te re n d e rin g i t more b a s ic and th e re b y
d is s o lv in g some of th e aluminum. P arso n s and B arnes
recommend te n grams of sodium b ic a rb o n a te p e r 100 m l.
and b o ilin g f o r one m in u te. Due to a d s o rp tio n e f f e c t s ,
two or th r e e p r e c i p i t a t i o n s a re n e c e s s a ry , th e
combined f i l t r a t e s c o n ta in in g th e b e ry lliu m .
B r itto n found t h a t th e amount o f b e ry lliu m
25 P arso n s and B arn es, J . Am. Chem. S o c ., 28, 1589 (1906)
ad so rb ed w ith th e aluminum h y d ro x id e v a rie d w ith th e
amounts o f each p re s e n t b u t av erag ed ab o u t f iv e p e r
o e n t of b e ry lliu m oxide ad so rb ed , u sin g from 0 .1 to
0 .0 1 grams o f each o x id e . Two p r e o ip it a ti o n s gave
v e ry good r e s u l t s as shown by B ritto n * s experim ents*
Grams AlgQg Grams BeO
Taken Found Taken Found
0.0226 0.0226 0.1409 0.1406
0.0792 0.0795 0.1106 0.1106
0.0852 0.0855 0.0941 0.0940
0.1537 0.1542 0.1421 0.1417
0.1087 0 ,1 0 9 0 0.0132 0.0129
B r itto n concluded th a t th e m ethod was e n t i r e l y
s a t i s f a c t o r y p ro v id in g two p r e o ip it a ti o n s were made
w ith th o ro u g h s t i r r i n g and t h a t th e b e ry lliu m and th e
aluminum in th e c a rb o n a te s o lu tio n w ere n o t more th a n
0 .1 5 grams p e r 100 m l. as a s a f e ty m easure to keep
th e b e ry lliu m w ith in i t s l i m i t s o f s o l u b i l i t y .
H. F is c h e r86 o b je c ts to th e sodium b ic a rb o n a te
m ethod on th e grounds t h a t th e b a s ic c a rb o n a te o f
aluminum form ed d u rin g th e p r e c i p i t a t i o n w ith sodium
b ic a rb o n a te is s o lu b le to th e e x te n t o f 0 .7 mg of
aluminum oxide in 100 m l. of s o lu tio n . He s t a t e s
th a t u s in g a t r i p l e p r e c i p i t a t i o n o f th e h y d ro x id e
from each 150 m l. s o lu tio n and u sin g 50 m l. o f wash
in g s o lu tio n , th e amount o f aluminum oxide e n te rin g
th e b e ry lliu m f i l t r a t e i s 4 .2 mg. T h e re fo re , u sin g a
26 H. F is c h e r, "Beryllium **, S-iem ens-K onzem , 24-28
te n p e r c e n t b e ry lliu m oxide ore w ith 0 .5 g r . i n i t i a l
w eig h t, th e re would be a c o rresp o n d in g f i n a l w eight
o f 54 mg o f b e ry lliu m oxide in s te a d of th e q u a n tity
50 mg to be e x p e c te d . He f u r t h e r co n ten d s th a t th e
iro n h y d ro x id e p o s s e s s e s a c e r t a i n s o l u b i l i t y and
th e r e f o r e on m aking a s y n th e tic m ix tu re re p re s e n tin g
an ore h av in g a co m p o sitio n of 1 0 .0 4 $ BeO, 2 0 .06$
AlgOg and 1 .5 $ #©2 ° 3 i he o b ta in e d an av erag e o f
1 1.25$ o f b e ry lliu m oxide o r an 1 1 .9 $ e r r o r .
Upon u sin g th e q u in a lis a r in m ethod which he
s u p p o rts , he o b ta in e d an average o f 9 .8 8 $ BeO o f
t h i s same p r e p a r a tio n .
F is c h e r a ls o o b je c ts t o th e sodium c a rb o n a te
fu s io n of the b e r y l o re . He fa v o rs th e m ethod by
which one gram o f the f in e l y d iv id e d powdered m in e ra l
i s mixed w ith th e same amount of sodium s i l i c o -
f lu o r id e and the m ix tu re ig n ite d in a new p o rc e la in
o r iro n c r u c ib le a t a te m p e ra tu re of betw een 680° an&
710° C. f o r th r e e h o u rs . Ih e re s id u e i s e x tra c te d
w ith w ate r and c a u s tic soda added u n t i l an a l k a l i n i t y
Of N/4 i s p ro d u ced . An a liq u o t p a r t o f t h i s s o lu tio n
i s th e n o o lo r im e tr ie a lly t i t r a t e d , w ith th e use of
q u in a liz a r i n . !Ehe fu s io n w ith sodium s i l i o o - f l u o r i d e
p ro d u ces s i l i c o n f lu o r i d e which form s f lu o r id e s o r
double f lu o r id e s of b e ry lliu m and aluminum* She
sodium b e ry lliu m f lu o r i d e and b e ry lliu m f lu o r id e
are s o lu b le in w a te r w h ile aluminum f lu o r id e and
sodium aluminum f lu o r id e a re not* fh e iro n i s
p r e c i p i t a t e d out in th e form of In s o lu b le PegOg.
A ta b le i s g iv en com paring th e r e s u l t s o f th e
a n a ly s is of th re e b e r y l o res by th e c o lo rim e tr ic
a i l i c o - f l u o r i d e m ethod and the b ic a rb o n a te and
c o lo rim e tr ic m ethods a f t e r sodium c a rb o n a te fu s io n .
% BeO o b ta in e d by % BeO by soda fu sio n
th e c o lo rim e tr ic
s i l i c o - f l u o r i d e g r a y im e tr io a lly o o lo r i-
method (b ic a rb o n a te ) m e tric a lly
B e ry l I 9*64 1 1 .7 9 ,8 4
10.40
B e ry l I I 1 2 .0 4 1 6 .6 11.8
B e ry l I I I 4 .4 1 7 .3 4 .4 2
4*66 4 .6 2
In th e fa c e o f such f i g u r e s , i t lo o k s a s i f th e
accu racy o f th e P arso n s and B arnes m ethod h a s been
o v erestim ated * However, th e r e s u l t s o b ta in ed by many
w orld known a n a ly s ts u sin g th e P arso n s and B arnes
method of p r e c i p i ta t i o n w ith sodium b ic a rb o n a te a re
e n t i r e l y s a t i s f a c t o r y , and as f a r as i s known, th e
r e s u l t s o b ta in e d by H ellm ut F is c h e r of th e Siem ens-
Konzern Chem ical Company in Germany have n o t been f u l l y
s u b s ta n tia te d .
EXPERIMENTAL DETERMINATION O J* BERYLLIUM: BT
PARSONS A N D BARNES M ETH O D
The m ethods w hich a re d e s c rib e d in th e l i t e r a
tu r e on b e ry lliu m c o n s is t of an a n a ly s is of known
amounts o f a m ix tu re of p u re aluminum and p u re
b e ry lliu m s a l t s , and com puting th e p e rc e n ta g e of
e r r o r from th e r e s u l t s obtained* S ince any commer
c i a l a n a ly s is f o r b e ry lliu m would be from impure
s a l t s o r o res c o n ta in in g b e ry lliu m , aluminum, iro n
and s i l i c a t e s , th e n e x t s te p would be to s t a r t from
th e b e ry lliu m ore i t s e l f and go th ro u g h th e e n tir e
e lim in a tio n of th e u n d e s ira b le c o n s titu e n ts , then
com paring th e r e s u l t s o b ta in e d by th e d i f f e r e n t
m ethods used*
In o rd e r to have a s ta n d a rd sam ple from w hich to
work and to e lim in a te a s f a r a s p o s s ib le any e r r o r
w hich m ight be in v o lv ed th ro u g h th e s e p a ra te w eigh
in g and sodium c a rb o n a te fu s io n o f each sam ple, a
la rg e b a tch was h an d le d in th e fo llo w in g manner*
A pproxim ately 12 grams of f in e ly ground b e r y l
ore was w eighed o u t. A pproxim ate b a tc h e s o f two
gram s each were p la c e d in a la rg e p la tin u m c r u c ib le
and in tim a te ly m ixed w ith about te n grams o f anhydrous
sodium c a rb o n a te . The m ix tu re was co v ered w ith a th in
b la n k e t o f th e p u re sodium c a rb o n a te and th e c ru c ib le
co v e re d . I t was g r a d u a lly h e a te d t o th e f u l l capa
c i ty of a F is c h e r b u rn e r. A fte r b la s tin g from f o r t y
t o s i x t y m in u tes, th e m e lt became c l e a r and th e b u rn e r
was rem oved. Ih en c o o l, th e e n tir e c r u c ib le was
p la c e d in a 600 m l. b e a k e r and 150 m l. of s ix norm al
h y d ro c h lo ric a c id ad d ed , th e b e a k er being covered
to p re v e n t lo s s by s p a tte r in g . When th e a c tio n had
ceased , th e p la tin u m c ru c ib le and l i d were removed
and w ashed, th e w ashings b ein g added t o th e s o lu tio n .
The s o lu tio n was th e n ev a p o ra ted to d ry n ess on th e
w a te r b ath in o rd er to d eh y d rate th e s i l i c a . The
re s id u e o b ta in e d was d eh y d rated f o r two h o u rs a t
105° to 110° C. This was th en d ig e s te d f o r te n
m in u tes on th e w ate r b ath w ith 2 0 m l. o f h y d ro c h lo ric
a c id ( s p . g r . 1 .1 ) . The m ix tu re was d ilu te d w ith
1 0 0 m l. c o ld w a te r and f i l t e r e d , th e re s id u e b ein g
washed w ith c o ld w a te r c o n ta in in g one p e r c e n t of
c o n c e n tra te d h y d ro c h lo ric a c id .
Not b ein g p r im a r ily in t e r e s t e d in th e s i l i c a t e
re s id u e , t h i s was d is c a rd e d and th e f i l t r a t e c o n ta in
ing th e b e ry lliu m , iro n and aluminum was p la c e d in a
two l i t e r b o t t l e . A fte r h aving o b ta in e d , in th e above
m anner, th e f i l t r a t e s from th e sodium ca rb o n a te
fu s io n and. su b se q u en t s i l i o a t e rem oval, th e s e f i l
t r a t e s were combined and d ilu te d to two l i t e r s .
T his two l i t e r s o lu tio n was ta k e n as a s ta n d a rd
of ocaaparison by w hich th e d if f e r e n t m ethods of
b e ry lliu m a n a ly s is c o u ld be w eighed a g a in s t each
o th e r.
The f i r s t method u sed was the P arso n s and B arnes
sy stem . F i f t y m l. was drawn from th e s o lu tio n f o r
each sam ple, The a n a l y t i c a l p ro ced u re was as fo llo w s :
To th e §0 m l. of s l i g h t l y a c id s o lu tio n ,
hydrogen su lp h id e was p asse d i n . A lthough no v i s i b l e
p r e c i p i t a t e o th e r than s u lp h u r was o b ta in e d , th e
s o lu tio n was f i l t e r e d . The hydrogen s u lp h id e gas
rem aining in th e f i l t r a t e was e x p e lle d by b o ilin g .
About 1 m l. of n i t r i c a c id was added in o rd er to
o x id iz e th e ir o n . The h y d ro x id es of b e ry lliu m ,
aluminum and iro n were th e n p r e c i p i t a t e d by th e a d d i
tio n w ith c o n s ta n t s t i r r i n g o f an ex cess o f ammonium
h y d ro x id e .
The ammonium h ydroxide used was f r e s h ly p re p a re d
and p re s e rv e d in th e fo llo w in g m anner; 2 0 0 ml* of con
c e n tr a te d ammonia s o lu tio n was p la c e d in a F lo re n c e
F la s k and d i s t i l l e d in to a n o th e r F lo re n c e F la s k con
ta in in g 150 m l. of d i s t i l l e d w a te r. The ammonia was
allo w ed to b ab b le in to th e d i s t i l l e d w a te r. In
o rd e r to keep th e d i s t i l l e d w a te r co o l so t h a t a
maximum amount of ammonia gas would be ab so rb e d ,
th e f l a s k was su rro u n d ed by a la r g e r v e s s e l con
ta in in g about o n e -h a lf g a llo n of w a te r. The
d i s t i l l a t i o n was c o n tin u e d a t about 70° to 80° C.
u n t i l no more ammonia co u ld be d e te c te d by i t s odor
in th e o r ig in a l f l a s k . The p re p a re d ammonia was
th e n p re s e rv e d in a f l a s k lin e d w ith o e re s in wax.
The ammonia th u s p re p a re d was u sed in a l l hy d ro x id e
p r e c i p it a t i o n s and in a l l n e u t r a liz a tio n s sin c e i t
was e n t i r e l y f re e from d is s o lv e d s i l i c a .
The h y d ro x id es p r e c i p i ta t e d by t h i s ammonia were
c o a g u la te d by h e a tin g t o b o ilin g . The b e a k e r was
th e n s e t a s id e u n t i l th e h y d ro x id es had s e t t l e d some*
w h at. The s o lu tio n was f i l t e r e d , p o u rin g a s much o f
th e d e a r s u p e rn a ta n t liq u i d as p o s s ib le th ro u g h th e
f i l t e r . As soon as th e h y d ro x id e p r e c i p i t a t e i s
p la c e d in th e f i l t e r , th e c o l lo id a l p a r t i c l e s o f th e
p r e c i p i t a t e e n te r th e p o re s of th e f i l t e r p a p e r and
re n d e r th e f i l t r a t i o n ex c e e d in g ly slow . T his p r e c i p i
t a t e c o n ta in in g a l l th e b e ry lliu m , aluminum and iro n
was washed w ith a two p e r c e n t s o lu tio n of ammonium
a c e ta te , being c a r e f u l to add enough ammonia to th e
w ashing l i q u i d to re n d e r i t a l k a l i n e ..
The e n t ir e f i l t e r p a p e r c o n ta in in g th e p r e c i p i
t a t e was removed from th e fu n n e l and p la c e d in a
b e a k e r where th e h y d ro x id es were d is s o lv e d by th e
a d d itio n o f d ilu t e h y d ro c h lo ric a c id . The s o lu tio n
was n e x t o x id iz e d by n i t r i c a c id , and th e n n e u tr a liz e d
w ith ammonia t o th e p o in t where th e s o lu tio n was s t i l l
j u s t c l e a r .
T his s o lu tio n was th e n d ilu te d to 10Q m l. w ith
c o ld w a te r and te n grams of sodium b ic a rb o n a te added,
ta k in g c a re to p re v e n t lo s s by e ffe rv e s c e n c e . The
m ix tu re was th en h e a te d to b o ilin g and b o ile d from
f o r t y - f i v e to s ix t y seco n d s, th en cooled and f i l t e r e d .
The re s id u e was washed w ith h o t te n p e r c e n t s o lu tio n
of sodium b ic a rb o n a te .
The r e te n tio n of th e f i r s t f i l t e r p ap e r reduced
to f ib e r s in th e s o lu tio n h a s a b e n e f ic ia l e f f e c t in
th a t i t p re v e n ts th e to o r a p id e v o lu tio n of carbon
d io x id e and steam, from th e s o lu tio n when h e a tin g ,
w hich red u ces any m ech an ical lo s s to a minimum.
Due t o th e c o llo id a l n a tu re of th e p r e c i p i t a t e
and i t s a d s o rp tio n e f f e c t s , th e p r e c i p i t a t e was d i s
so lv e d in d i lu t e h y d ro c h lo ric a o id , o x id iz e d w ith
n i t r i c a o id , d ilu te d to 1 0 0 m l. and te n grams of
sodium b ic a rb o n a te a g ain ad d ed . The m ix tu re was
th e n b o ile d f o r one m in u te, co o led and f i l t e r e d .
Since t h i s does n o t co m p lete ly f r e e th e
b e ry lliu m from th e adsorbed iro n and aluminum
h y d ro x id e s, th e p r e c i p i t a t e was a g a in d is s o lv e d in
d ilu t e h y d ro c h lo ric a o id , o x id iz e d w ith n i t r i c a c id ,
d ilu te d to 1 0 0 m l. and te n grams of sodium b ic a rb o n
a te added and b o ile d f o r one m in u te , The p r e c i p i t a t e
was f i l t e r e d o f f and th e f i l t r a t e s from th e th r e e
s im ila r p r e c i p i t a t io n s were com bined,
The s o lu tio n c o n ta in in g th e combined f i l t r a t e s
was slo w ly and c a r e f u lly a c i d i f i e d w ith h y d ro c h lo ric
a c id and th e carbon d io x id e co m p letely removed by
b o ilin g , th e b e a k e r b e in g covered t o p re v e n t m echani
c a l l o s s . B e ry lliu m hydroxide was th en p r e c i p i t a t e d
by th e a d d itio n o f a s l i g h t ex c ess of ammonia and th e
s o lu tio n h e a te d to c o a g u la te th e p r e c i p i t a t e .
When th e hy d ro x id e had s e t t l e d , i t was f i l t e r e d
through #41 Whatman f i l t e r p a p e r and washed arith a
two p e r c e n t s o lu tio n of ammonium a c e ta te c o n ta in in g
a l i t t l e f r e e ammonia. When th e re sid u e had been washed
f r e e from c h lo rid e s , th e f i l t e r p a p e r and th e p r e c i p i
t a t e were p la c e d in a p la tin u m c r u c ib le and ig n ite d .
Since b e ry lliu m oxide i s s l i g h t l y h y g ro sc o p ic , th e
ig n ite d re s id u e was w eighed q u ic k ly ,
The r e s u lt s o b ta in e d from th e P arso n s and B arnes
method u sin g 50 m l, of th e s ta n d a rd s o lu tio n a re as
f o llo w s :
r
W eight of BeO
Sample 1 0.0301
* £ 0.0305
* 3 0 .0301
* 4 0.0303
DETEEMINATION O F THE SOLUBILITY O F
ALUM INUM IN SODIUM BICARBONATE
In accordance w ith th e p ro ced u re f o r th e
s e p a r a tio n of b e ry lliu m from aluminum and ir o n as
g iv en in th e P arso n s and B arnes m ethod, a t r i p l e
p r e c i p i t a t i o n of th e aluminum and iro n by a te n
p e r c e n t s o lu tio n of sodium b ic a rb o n a te i s c a lle d
f o r . I t i s claim ed by some who oppose t h i s method
t h a t due to th e s o l u b i l i t y of aluminum in a te n p e r
c e n t sodium b ic a rb o n a te s o lu tio n , the r e s u l t s o b ta in e d
f o r b e ry lliu m which was c o n ta in e d in th e f i l t r a t e
were to o h ig h . J a n d e r 2 7 g iv e s th e s o l u b i l i t y as 0 .7
mg. o f AlgOg in 1 0 0 ml* of te n p e r c e n t sodium b i
carb o n ate* H. T. S. B r itt o n 2 6 d eterm in ed th e s o lu
b i l i t y o f AlgOg and a ls o o f BeO in a s a tu r a te d s o lu tio n
of sodium b ic a rb o n a te . H is r e s u l t s show a s o l u b i l i t y
o f 0*4 mg. p e r 1 0 0 m l. so lu tio n *
B r itto n o b ta in e d h i s r e s u l t s by th e a d d itio n of
0 ,5 N aluminum s u lp h a te to a s a tu r a te d sodium b io a r -
b o n ate s o lu tio n u n t i l a v i s i b l e p r e c i p i t a t e was form ed,
which to o k 0 .0 5 m l. and was e q u iv a le n t to 0 .4 mg* o f AlgO^.
27 Ja n d e r and Weber, Z e it. A norg. Chem*, 151. 266, (1923)
28 H. T. S. B r itto n , A n a ly s t, 46, 437, (1921)
I t seemed t h a t f u r t h e r in v e s tig a tio n of th e
s o l u b i l i t y of aluminum in sodium b ic a rb o n a te s o lu
tio n was d e s ir a b le , so a s o lu tio n of p o ta ssiu m alum
was p re p a re d w hich was e q u iv a le n t to 0 * 1 gram
AlgQ3 p e r 20 m l. An eye d ro p p er was th e n c a l i
b r a te d by d e te rm in in g th e number of drops w hich were
re q u ire d t o m easure one m l. By t h i s m ethod one drop
was e q u iv a le n t to l/2 9 m l. The number of drops
which were re q u ire d v a rie d from th re e to s i x . Upon
changing th e se to m illig ra m s o f A I20 3 th e range
would be from 0 .5 mg. AlgO^ t o 1 . 0 mg. AlgO^ in 1 0 0
m l. o f te n p e r ce n t sodium b ic a rb o n a te s o lu tio n , a t
20° C.
These f ig u r e s are n e c e s s a r ily h ig h due to th e
i n a b i l i t y to a c c u ra te ly d eterm in e when a p r e c i p i t a t e
had form ed.
THE USE O P CA RB O N DIOXIDE GAS TO MAINTAIN
THE EQUILIBRIUM OP A BOILING SOLUTION OP
SODIUM BICARBONATE
The method f o r th e d e te rm in a tio n of b e ry lliu m
a s g iv e n by B arsone and B arnes2 9 recommends th e b o i l
in g o f th e sodium b ic a rb o n a te s o lu tio n o f b e ry lliu m ,
iro n and aluminum f o r one m in u te, sin c e i t was
d eterm in ed t h a t b e ry lliu m was more r e a d ily s o lu b le
in a h o t s o lu tio n .
When th e sodium b ic a rb o n a te s o lu tio n s a re
h e a te d , la rg e volum es of carbon d io x id e a re e v o lv ed .
T h e re fo re , an experim ent was p erfo im ed in o rd e r to
d eterm in e w h eth er o r n o t a s u f f i c i e n t amount of carbon
d io x id e would be l o s t to re n d e r some of th e aluminum
s o lu b le . I t was shown by B r itto n t h a t sodium c a rb
onate was to o b a s ic to q u a n t ita tiv e l y p r e c i p i t a t e
alum inum . T h erefo re th e sodium c a rb o n a te form ed by
th e lo s s of carbon d io x id e from th e sodium b ic a rb o n a te
s o lu tio n m ig h t be s u f f i c i e n t to d is s o lv e some aluminum.
The experim ent c o n s is te d of ru n n in g th re e
sam p les, one by b o ilin g th e sodium b ic a rb o n a te s o lu
tio n f o r 45 se co n d s, one by b o ilin g f o r one m inute
29 P arso n s and B arn es, (L o o .c it. )
and one by p a s s in g in carbon d io x id e a t th e r a te of
f o u r bubbles p e r second from a 1 / 8 inch o r i f i c e f o r
one m in u te .
The r e s u l t s show t h a t th e re is n o t enough
sodium c a rb o n a te foim ed by b o ilin g f o r one m inute
to d is s o lv e an a p p re c ia b le amount o f aluminum.
Sample
I
I I
I I I
T reatm ent
B o ile d 45 seconds
B o iled 60 seconds
B o iled 60 seconds
p assed in C0g a t r a te
of 4 b u b b les p e r second
B e su it
0.0301 g r . BeO
0.0303 g r .
» »
0.0301 g r .
A N INVESTIGATION O P THE USE OP SODIUM
BICARBONATE AS A PRECIPITATING AGENT FOR IRON
Due t o th e f a c t th a t ir o n was som etim es
p re s e n t in th e f i l t r a t e a f t e r th e tre a tm e n t of th e
aluminum, iro n and b e ry lliu m s o lu tio n s w ith sodium
b io a rb o n a te , an in v e s tig a tio n of th e use of sodium
b ic a rb o n a te as a p r e c i p i t a t in g a g e n t was p erfo rm ed .
In two c a se s d u rin g th e a n a ly s is , hydrogen
p e ro x id e was used in s te a d o f n i t r i c a c id to o x id iz e
th e ir o n . These sam ples, a f t e r tre a tm e n t w ith a
te n p e r c e n t s o lu tio n of sodium b ic a rb o n a te and su b
se q u en t p r e c i p it a t i o n w ith ammonia, were found to
c o n ta in more iro n than was o r i g i n a l l y p r e s e n t in th e
sam p les. When C. P . hydrogen p e ro x id e was u se d ,
how ever, th e sam ples appeared to be n o rm al.
Two sam ples o f fe rro u s ammonium s u lp h a te con
ta in in g ab o u t 0 .1 2 grams of w ere ta k e n . The
f i r s t sam ple was o x id iz e d w ith n i t r i c a c id and p re
c i p i t a t e d in a te n p e r c e n t s o lu tio n o f sodium
b io a rb o n a te . The second sample was o x id iz e d w ith
hydrogen p e ro x id e and p r e c i p ita t e d in a te n p e r ce n t
s o lu tio n of sodium b ic a rb o n a te . Iro n was found in
th e f i l t r a t e s o f both sam p les.
The r e s u l t s w hich w ere o b ta in e d a re as
f o llo w s :
I
I I
Sample
Fe found in
f i l t r a t e
O xidized w ith BHO
ppted. w ith 1 0 $
HaHCOg
0.1283
0.0141
3
O xidized w ith
HgOo, ppted-
w ith 10$ SaHOO,
0.1342
0.0130
3
From th e s e r e s u l t s i t i s q u ite c le a r t h a t th e
Sodium b ic a rb o n a te m ethod, as recommended by P arso n s
and B arn es, and so w id ely u sed , does n o t g iv e a
s a t i s f a c t o r y s e p a ra tio n from ir o n . F u rth e r in v e e ti -
g a tio n o f t h i s phase of th e problem w ould be w e ll
w orth w h ile . In th e m eantim e, i t i s s a fe to say
t h a t i f b e ry lliu m i s determ ined in an ore c o n ta in in g
ir o n , th e f i n a l w eighed p r e o i p i t a t e of b e ry lliu m oxide
sh o u ld be fu se d w ith p o tassiu m p y r o s u lf a te and a
c o lo rim e tr ic d e te rm in a tio n of th e ir o n c o n ta in e d in
th e p r e o i p i t a t e sh o u ld be made. T his ir o n , c a lc u
l a t e d as FegOg, sh o u ld be s u b tr a c te d from th e w eight
of th e ig n ite d p r e o i p i t a t e to g iv e th e tr u e w eight of
th e b e ry lliu m o x id e .
2 8.
A N EXPERIMENTAL DETERMINATION OP BERYLLIUM
BY THE M ETH O D O P EQLTHQPP AN D SANDELL
The n e x t method used was th a t p u b lis h e d by
30
K o lth o ff and S an d e ll w hich makes use o f oxine
ox 8 -h y d ro x y q u in o lin e In a ^ s o lu tio n o f two
n o m a l a o e tie a c id . Ten m l. of th e re a g e n t th u s
p re p a re d i s s u f f i c i e n t to p r e c i p i ta t e one m i l l i
mole o f aluminum.
An a liq u o t p o r tio n of th e p re v io u s ly m entioned
s ta n d a rd s o lu tio n was ta k en f o r each sam ple. The
s o lu tio n was n e u tr a liz e d w ith ammonia and th en made
s l i g h t l y a c id w ith a c e ti c a c id . The s o lu tio n was
warmed to 50° o r.* 60° 0 . and a n ex c ess of th e a c e ti c
a c id s o lu tio n o f oxine added. Two norm al ammonium
a c e ta te was slow ly added u n t i l a perm anent p r e c i p i
t a t e was o b ta in e d , and th en an excess o f tw enty to
t h i r t y m l. m ore. When th e p r e c i p i t a t e o f (CgH^QNjg A1
had s e t t l e d , th e liq u id was drawn by s u c tio n through
a H irsc h fu n n e l. T h is p r e c i p i t a t e h a s a g re e n ish
y ello w c o lo r . I f th e aluminum i s w anted, the p r e c i p i
t a t e i s w ashed w ith c o ld w a te r and d rie d a t 1 2 0 ° to
140° 0 . T his p r e o ip i t a t e c o n ta in s 11*1$ o f AlgO^.
30 K o lth o ff and S a n d e ll, Amer. Chem. S o c ., 50, 1900, (1928)
N ot b e in g in te r e s te d in th e aluminum p r e a i p i -
t a t e , i t was d is o a rd e d . The f i l t r a t e was h e a te d
n e a rly to b o ilin g and ammonium h ydroxide c a r e f u l ly
added u n t i l th e s o lu tio n sm elled f a i n t l y o f ammonia*
The b e ry lliu m h y d ro x id e p r e c i p ita t e d in t h i s manner
ap p ears t o be more volum inous and h as a yellow
c o lo r due to adsorbed o x in e . The p r e c i p i t a t e was
f i l t e r e d and th o ro u g h ly washed w ith h o t d i l u t e
ammonium a c e ta te c o n ta in in g a few drops of ammonium
h y d ro x id e . The p r e c i p i t a t e was d r ie d , ig n ite d and
quiofcly w eighed.
The r e s u l t s o b ta in e d by t h i s m ethod u sin g 100 m l.
w ere a s fo llo w s :
Sample W eight of BeO
1 0.0580
2 0.0504
3 0.0588
4 0.0580
5 0.0579
COM PARISON OF THE M ETH O D O F
PARSONS A ND BARNES WITH THAT OF
KOLTHOFF A N D SANDELL BY M EANS OF PURE SOLUTIONS
The r e s u l t s o b tain ed by th e use o f th e m ethod
of K o lth o ff and S an d ell when compared w ith th o se
o b ta in ed by th e method of P arso n s and B arnes were
low in ev e ry case* An av erag e of th e r e s u l t s ob-
ta in e d from th e s ta n d a rd sam ple by th e P arso n s and
B arnes m ethod was found t o be 0.0604 gram s of BeQ
p e r 100 m l. o f s o lu tio n . The r e s u l t s o b ta in e d by
th e use o f th e oxine m ethod of K o lth o ff and S a n d e ll
av erag ed 0.0582 grams of BeO p e r 100 m l. o f s ta n d a rd
s o lu tio n . Computing th e p e rc e n ta g e o f e r r o r assum
in g th e sodium b ic a rb o n a te method t o be c o r r e c t , a
v alu e of - 3 . 6$ was o b ta in e d .
In o rd e r t o check on th e s e r e s u l t s , a s o lu tio n
of pure b e ry lliu m n i t r a t e was made so t h a t by
a n a ly s is i t c o n ta in e d 0.1348 gram s o f BeO p e r £5 m l.
A lso a s o lu tio n o f alum was p re p a re d w hich had an
aluminum oxide c o n te n t o f 0.15 gram p e r 25 m l. The
b e ry lliu m was s ta n d a rd iz e d by p r e c i p i t a t i o n w ith
ammonia.
Samples were made c o n ta in in g 25 m l. of th e
Sodium b io a rb o n a te
P arso n s and B arnes
Grams BeO
0.1348
0.1350
0.1345
8 -hydroxyquin o lin e
K o lth o ff and S a n d e ll
B rans BeO
0.1257
0.1253
b e ry lliu m s o lu tio n and 25 m l. of th e alum so lu tio n *
She b e ry lliu m c o n te n t o f th e s o lu tio n s was d eterm in ed
by both th e sodium b io a rb o n a te method and by th e
oxine m ethod. The r e s u l t s o b ta in e d by th e oxine
method were ag ain low*
S ta n d a rd iz a tio n
Grams BeO
0.1348
0.1347
0.1348
Computing th e p e rc e n ta g e of e r r o r , a v a lu e of
-6 .9 $ was fou n d .
In com paring t h i s e r r o r o f 6 .9 $ w ith th e value
o f 3 .6 $ o b ta in e d by th e d e te rm in a tio n s made on th e
o re , a d if fe re n c e of 3 .3 $ i s fo u n d . T his d if fe re n c e
may be e x p la in e d by th e f a o t th a t th e ore sam ples
c o n ta in e d only 0.0303 grams o f BeO w h ile th e p re p a re d
sam ples c o n ta in e d 0.1348 grams of BeO, I t may be
co n clu d ed , th e r e f o r e , th a t th e oxine method f o r th e
d e te rm in a tio n of b e ry lliu m te n d s to g iv e r e s u l t s which
a re s l i g h t l y low er th a n the tr u e v a lu e s .
S U M M A R Y
In stu d y in g m ethods f o r th e d e te rm in a tio n of
b e ry lliu m in th e p re se n c e of aluminum, i t h a s been
shown th a t th e m ethod of P arso n s and B arn es, based
upon th e s o l u b i l i t y o f b e ry lliu m compounds in sodium
b io a rb o n a te s o lu tio n u n d e r c e r t a in w e ll re g u la te d
c o n d itio n s , and th e i n s o l u b i l i t y of aluminum
h y d ro x id e o r b a s ic c a rb o n a te u n d er the same c o n d itio n s ,
y ie ld s r e s u l t s w hich a re a c c u ra te w ith in lim its of
re a so n a b le e x p e rim e n ta l e r r o r .
The 8-hy& roxyquinoline m ethod o f K o lth o ff and
S a n d e ll h a s been found to g iv e r e s u l t s f o r b e ry lliu m
t h a t a re to o low .
Hew d e te rm in a tio n s of th e s o l u b i l i t y o f aluminum
in a s o lu tio n o f sodium b ic a rb o n a te have been made*
I t h as been shown t h a t iro n is n o t co m p letely
s e p a ra te d from b e ry lliu m , a s h as h e re to fo re alw ays
been assum ed, by b o ilin g th e m ix tu re of th e two
w ith sodium b io a rb o n a te s o lu t io n ; and n e c e s s ity has
been shown f o r f u r t h e r tre a tm e n t of th e b e ry lliu m
o x id e, fo llo w ed by a c o lo rim e tric d e te rm in a tio n of
th e co n tam in atin g ir o n .
The u se o f a c u rre n t of carbon d io x id e in m ain
ta in in g th e e q u ilib riu m in a b o ilin g s o lu tio n of sodium
b ic a rb o n a te h as been s tu d ie d , and i t has been shown
to be u n n ec essary f o r th e s e p a ra tio n of b e ry lliu m
and aluminum*

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Creator Newsom, W. R (author)

Core Title A critical study of the methods for the quantitative determination of beryllium

Degree Master of Arts

Degree Program Chemistry

Publisher University of Southern California (original), University of Southern California. Libraries (digital)

Tag chemistry, inorganic,OAI-PMH Harvest

Language English

Contributor Digitized by ProQuest (provenance)

Advisor [illegible] (committee chair), [illegible] (committee member)

Permanent Link (DOI) https://doi.org/10.25549/usctheses-c17-786343

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Legacy Identifier EP41469.pdf

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Rights Newsom, W. R.

Type texts

Source University of Southern California (contributing entity), University of Southern California Dissertations and Theses (collection)

Access Conditions The author retains rights to his/her dissertation, thesis or other graduate work according to U.S. copyright law. Electronic access is being provided by the USC Libraries in agreement with the au...

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