The electrolytic synthesis of battery active manganese dioxide
by Edward F Sylvain
A THESIS Submitted to the Graduate Faculty in partial fulfillment of the requirements for the degree
of Master of Science in Electrical Engineering
Montana State University
© Copyright by Edward F Sylvain (1950)
Abstract:
The experimental work concerning the electrode stability, current efficiencies, and power requirement
per unit weight of manganese dioxide has been undertaken to establish the type of electrical load to be
expected in the electrolytic production of battery active manganese dioxide from Montana manganese
bearing ores. The results have been considered not only to the applicability of the electrical load to a
commercial process but also as to the quality of the product. THE ELECTROEITiC SYNTHESIS OF BATTERY ACTIVE
MANGANESE DIOXIDE
EDEARD F . •SYLVAIN
■ A THESIS
S u b m itted t o th e G raduate F a c u lty
p a r t i a l f u l f i l l m e n t o f th e re q u ire m e n ts
f o r th e d eg ree o f
M aster o f S cien ce i n E l e c t r i c a l E n g in e e rin g
Montana S ta te C o lleg e
Approved:
Hekdj M ajor "Department
C h airm an, Exam ining Committee
'BAan , G raduate D iv is io n
Bozeman, M ontana
A ugust, 1950
hi i t ?
S'l* £*
Cy>. I*
- 2 TABLE OF CONTENTS
Page
£
ABSTRACT......................................................................
I
I n tr o d u c ti o n ........................................................................................
£
II
E x p erim en tal Work .................................... . . . . . . . . .
8
III
A.
A pparatus
. . . . . . . . . . . . . . . . . .
8
1 . Power S u pply. . . . . . . .
...................................
8
2 . E l e c tr o ly te C o n ta in e r and E x te rn a l H eat Supply 10
3« E l e c tr o ly te and E le c tro d e S u p p o rts ........................... 11
Iu D rying Oven ..................................
12
B.
P rocedure
............................... .... .................................. 13
I . P r e p a r a tio n o f th e E l e c t r o l y t e . . ............................13
'2 . E l e c t r o l y s i s . .................................................................
13
3 . Anode S t r i p p i n g ...................................................................lii
C.
O b se rv a tio n s and R e s u lts .......................................
16
1 . E le c tro d e S t a b i l i t y . . . . . . .
....................... 16
a . Anodes..............................
17
b . Cathode ...........................................
18
2 . C e ll V o ltag es ..........................
19
a . Anode C u rre n t D e n sity .............................................19
b . E l e c t r o l y t e A c id ity . . . . . . . . . . .
19
Ce E l e c t r o l y t e Manganese S u lp h a te C o n cen tra­
tio n s ................................................
20
d . Anode to Cathode S p a c in g . . . . . . . . .
20
3 . C u rren t E f f ic ie n c ie s and Kw-Hr P er Pound o f
MnO2 . ..............................
2D
a . Anode C u rre n t D e n sity . . . . .
.................. 23
b . E l e c t r o l y t e A c id ity . . . . .
...................... 2£
c . C e ll T em p eratu re. . . . . . . . . . . . .
23
d . Anode M a te r ia l. . . . . . . . . . . . . .
26
e . E l e c tr o ly te Manganese S u lp h a te C oncentra­
tio n s . . . . . . . . . . . . . . . . . .
2?
f . Anode to Cathode S p a c in g . . . . . . . . .
27
Iu E l e c t r o l y t i c MnO2 D a ta. . . . . . . . . . . .
28
3 . A n a ly sis o f E l e c t r o l y t i c MnOp . . . . . . . .
29
6 . R e s u lts o f B a tte ry Perform ance T e s ts . . . . .
29
Commercial A p p lic a b i lity o f E l e c t r i c a l Load
C h a r a c t e r i s t i c s ..................................................................
30
A.
30
C u rre n t D e n sity . . . . . . . .
.....................................
95124
3
-
-
B0 E l e c t r o l y t e C o n c e n tra tio n s , , . .................................... - , . . S l i
Co
Power F a i l u r e , . . . . . . . .
. . . . . . . . . . .
D0 E le c tro d e S pacing and C e ll S iz e . . . . . .
. . . . . 3 6
IF
C
n
V
L i t e r a t u r e C ite d
VI
•A.pp®ildux. . . . . . . . .
o
n
c
l
u
s
i
o
s
38
. . . . . .
. . . . . . . . . .
T able I
E l e c t r o l y t i c MnO2 D a ta . . . . . . . . . . . .
T able I I
A n a ly sis o f E l e c t r o l y t i c MhO2
T able I I I B a tte r y T e s t D ata . . . . . . . .
F ig u re 2
F ig u re 3
37
. IiO
!46
. . . . . . . I i ? '
The R e la tio n o f C u rre n t E f f ic ie n c y , E nergy
R equirem ents and C e ll V o ltag e to V arious
C u rre n t D e n s itie s . . . . . . . . . . . . . . . .
!48
The R e la tio n o f C u rre n t E f f ic ie n c y , Energy
R equirem ents, and C e ll V o ltag e to V arious
E l e c t r o l y t e Acid C o n c e n tra tio n s . . . . . . . .
Ii9
F ig u re U The R e la tio n o f C u rre n t E f f ic ie n c y and Energy
R equirem ents to V arious Manganese S u lp h a te
C o n c e n tra tio n s . . . * . . , «
. . . . . . . . . .
F ig u re 5
The R e la tio n o f C u rre n t E f f ic ie n c y , Energy
R equirem ents, and C e ll V o ltag e to E le c tro d e
S p acing 0 . . . . . . O . . . . . . . o . . .
X
. 51
-IlABSTRACT
The e x p e rim e n ta l work concernin g th e e le c tr o d e s t a b i l i t y , c u r­
r e n t e f f i c i e n c i e s , and power re q u ire m e n t p e r u n i t w eig h t o f manganese
d io x id e has .been u n d e rta k en to e s t a b l i s h th e type o f e l e c t r i c a l lo a d
to be e x p e c te d i n th e e l e c t r o l y t i c p ro d u c tio n o f b a t t e r y a c tiv e man­
ganese d io x id e from Montana manganese b e a rin g ores* The r e s u l t s have
been c o n sid e re d n o t o n ly to th e a p p l i c a b i l i t y o f th e e l e c t r i c a l lo a d
to a com m ercial p ro c e ss b u t a ls o a s to th e q u a lity o f th e p ro d u ct*
—5 ^
I INTRODUCTION
The s u c c e s s f u l p ro d u c tio n o f " b a tte ry a c tiv e manganese d io x id e i s
a m a tte r o f c o n sid e ra b le "im portance f o r b o th m i l i t a r y and com m ercial
u tiliz a tio n .
In war tim e s , .e s p e c ia lly d iirin g th e l a s t w orld w ar, th e r e
was a heavy demand f o r a manganese d io x id e t h a t would be' p u re enough
a c t a s a d e p o la r iz e r in d ry c e l l b a t t e r i e s .
to
I n th e p a s t , t h i s demand
h a s b een met by n a t u r a l ore s u p p lie s m ain ly from th e A fric a n Gold C o ast.
In th e fu tu r e ,., i t i s .e v i d e n t from, th e r e s u l t s o f t h i s t h e s i s and o th e r
t r e a t i s e s co n ce rn in g manganese d io x id e p ro d u c tio n t h a t th e demand w il l '
be met' by -an e l e c t r o l y t i c manganese d io x id e .
O bviously t h i s w i l l "be a
r
bonus t o American in d u s tr y .
Since- th e c h ie f source o f " n a tu r a l .ore a v a ila b le to th e U n ite d S ta te s
i s th e A fric a n 'Gold Coast o re , the p ro d u c tio n o f e l e c t r o l y t i c manganese
d io x id e from l o c a l ore. s u p p lie s h a s. a tw o fo ld e f f e c t :
(I) sh o p ld th e ' '
n a t u r a l ore su p p ly be c u t o f f , n a tio n a l s e c u r i t y w i l l n o t be je o p a rd iz e d
by la c k o f - b a t t e r y a c tiv e manganese d io x id e ; (S) an abundant su p p ly o f ■
o re h e r e t o f o r e . n o t used f o r .b a t t e r i e s (r h o d o c h ro s ite ) , can now be u t i l i z e d
in th e e l e c t r o l y t i c p ro c e s s to y ie ld a b a t t e r y a c tiv e manganese d io x id e
w ith b e t t e r c h a r a c t e r i s t i c s th a n n a t u r a l o re s u n d er heavy c u r r e n t d ra in
c o n d itio n s .
R u ssia n p y r o l u s i t e , p re v io u s to 1914, was a s ta n d a rd d e p o la r iz e r used
in d ry c e l l s .
The su p p ly was , c u t . o f f due t a World. War I , and-nat.ive_p.yro-
l u s i t e s were t r i e d w ith poor r e s u l t s .
These r e s u l t s le d e x p e rim e n te rs to
b e lie v e t h a t som ething more th a n th e manganese d io x id e c o n te n t determ ined
- 6 th e a c tio n in th e c e l l s , s in c e n a tiv p p y r o lu s ite w ith a s much a s ninety-r
f i r e p e r c e n t m an g an ese'd io x id e was t r i e d , a s a s u b s t i t u t e f o r R u ssia n
p y ro lu s ite .
E l e c t r o p l a t i n g o f mangapese d io x id e has been in th e e x p e r i­
m e n tal s ta g e s in c e a s e a r l y .a s 1918-, how ever, a t t h a t tim e th e im port­
ance o f th d ' c r y s t a l . s t r u c t u r e 'o f .'t h e ; manganese ■d io x id e was n o t re c o g n iz e d .
L a te r work- done .by G-.., W. N ich o ls (I) i n 1932, b ro u g h t t o l i g h t some o f th e
.problem s in v o lv e d in th e p ro d u c tio n o f e l e c t r o l y t i c manganese d io x id e ;
nam ely th e-d ep en d en ce o f th e e l e c t r q p l a t i h g on- th e m ic ro sco p ic s u rfa c e
o f 'th e anode.
One .year . l a t e r , Dr. P e te r Marx (2) p u b lis h e d a paper a t
B itte r f e ld - , Germany w hich d i d . I i t t l q more, th a n 'c o n f ir m Am erican con­
c lu s io n s oh t h e 'm a t t e r * '
_
I t w asn’t . u n t i l World.War- I I t h a t , w ith th e in c re a s e d r e s e a r c h due
t o .th e s h o rta g e o f ■n a t u r a l manganese d io x id e o r e , th e im portance o f th e .
c r y s t a l s t r u c t u r e became a p p a r e n t .. T h e.ty p e o f c r y s t a l s tr u c tu r e found
t o be m o s t- s a t is f a c to r y f o r use in d ry c e l l b a t t e r i e s is c a lle d "gammas tr u c tu r e " - .o r , more . commonly, '!gamma-phase" .
R e c e n tly ,. in 1949,. G eorgia
I n s t i t u t e -of T echnology ..(3 )'",d id ."a'co n sid erab le amount; o f w ork, under th e
a u s p ic e s o f ..the .U n ite d .States..A rm y S ig n a l "Corps, w hich i s d is c u s s e d in '
d e t a i l i n - t h e i r . r e p o r t t i t l e d "The E l e c t r o l y t i c . S y n th e s is o f B a tte r y
A ctiv e Manganese. D io x id e ".
The G e o r g ia .I n s t itu te o f Technology r e s u l t s
were a p o s itiv e in d ic a tio n t h a t the e l e c t r o l y t i c manganese d io x id e could
be produced un d er c e r t a i n p ro c e s s c o n d itio n s t o y ie ld gamma phase man­
ganese d io x id e .
A lso ; work c o n cern in g th e anode problem was conducted
a t Georgia- I n s t i t u t e o f T echnology.
F u r th e r re s e a rc h , on th e p ro je c t,...u n d e r th e a u s p ip e s .o f th e U n ited
S ta te s A rm y-Signal C orps, i s being- c a r r ie d on by th e Montana S ta te Col­
le g e E n g in e e rin g E xperim ent S t a t i o n a t Boss erne n , M ontana.
S in c e Montana
i s th e le a d in g p ro d u c e r o f manganese o r e s , Montana o re s such as rh o d o c h r o s ite from B u tte and p y r o l u s i t e from P h illip s b u r g a re u sed i n th e r e ­
s e a rc h w ork.
S in c e th e p ro c e s s o f p ro d u c in g b a t t e r y a c t i v e manganese d io x id e i s
o f an e le c tro c h e m ic a l n a tu r e , th e r e s e a r c h i s conducted as a j o i n t p ro ­
j e c t betw een th e E l e c t r i c a l E n g in e e rin g and th e Chem ical E n g in ee rin g
D epartm ents o f Montana S ta te C o lle g e .
-C onsequently, two th e s e s w i l l be
w r i t t e n on th e s u b je c t a t t h i s tim e .
This t h e s i s w i l l cover t h e e l e c t r i ­
c a l a s p e c ts o f th e r e s e a r c h , and a second t h e s i s by A rth u r M. Magriuson
w i l l in c o r p o r a te th e ch em ical e n g in e e rin g a s p e c ts 0
• '
'
'
B a tte r y perform ance t e s t s on two e l e c t r o l y t i c manganese d io x id e
sam ples from runs. Carbon 7 and Carbon 22 a re b e in g conducted :by th e .
S q u ie r S ig n a l L a b o r a to r ie s .
a re in c lu d e d i n t h i s t h e s i s .
The r e s u l t s of" th e i n i t i a l b a t t e r y t e s t
F u r th e r r e s u l t s from the.- S q u ie r S ig n a l
L a b o ra to rie s w i l l be a tta c h e d to t h i s t h e s i s Mien a v a i l a b l e .
Chem ical
a n a ly s e s on e l e c t r o l y t i c manganese d io x id e w ere co nducted by th e U nited
S ta te Army S ig n a l Corps L a b o ra to rie s on numerous S a n p le s0
—
8
—
• I I EXPERIMENTAL work
The fo llo w in g d is c u s s io n o f e x p e rim e n ta l work p e r ta in in g to the
t9APPARATUSH and "IROpEDURElt w i l l be incom plete" because th e d is c u s s io n
o f th e a p p a ra tu s u sed i n p re p a rin g t h e - e le p tr o ly te and th e p r e p a r a tio n
o f th e e l e c t r o l y t e i t s e l f w i l l be e x p la in e d i n d e t a i l i n th e chem ical
e n g in e e rin g t h e s i s .
I n t h i s t h e s i s m en tio n o f th e chem ical e n g in e e rin g
te c h n iq u e s u sed w i l l be o n ly q i a l i t a t i v e when c l a r i t y n e c e s s i t a t e s .
A. APPARATUS
The b a s ic equipm ent u sed i n th e r e s e a r c h w ork, a f t e r th e e l e c t r o l y t e
i s p re p a re d , a r e a s u i t a b l e d -c power s u p p ly , m ethod o f h e a tin g th e e l e c ­
t r o l y t e d u rin g o p e r a tio n , e le c tr o d e a n d ,e le c tr o d e s u p p o rts , and a d ry in g
oven to determ in e th e d ry w e ig h t o f anodes b e fo re and a f t e r o p e ra tio n .
I.
Power Supply
Run Carbon I power su p p ly was a 33 v o l t , 125 ampere d -c g e n e ra to r
w hich i s s t i l l a v a il a b le i n th e e l e c t r i c a l e n g in e e rin g la b o r a to r y i n "the
e v en t t h a t a g r e a t e r power su p p ly sh o u ld be n eed ed .
A d -c g e n e r a to r w ith
a c a p a c ity o f 50 v o l t s and 15 amperes was u se d i n a l l ru n s e x c e p t Carbon I .
To e x c it e th e f i e l d o f t h i s d -c g e n e r a to r , a " f r e e w h e elin g " r e c t i f i e r
d r e m i t was d e sig n e d .
The r e c t i f i e r , p ro v id e d a c o n v en ien t means o f con­
t r o l l i n g th e o u tp u t o f th e g e n e r a to r s in c e th e c o n tr o llin g v a r ia c o f th e
r e c t i f i e r was p la c e d d i r e c t l y on th e c e l l t a b l e .
The c a p a c ity o f th e d -c
g e n e ra to r was found to be q u ite s a t i s f a c t o r y f o r th e la b o r a to r y work be­
c a u se , by p ro p e r d e sig n o f th e anod es, i t was p o s s ib le t o o b ta in c u r r e n t
d e n s i t i e s up to hO am peres p e r sq u are f o o t .
In d e e d , th e c u r r e n t d e n s i t i e s
no v
2.5 V
CONTROL VARIAC;
O-> -12 0 V <
D-C
FIELD
GEN.
CELL
TABLE
F ig u re I - Schem atic Diagram o£ th e E l e c t r i c a l A pparatus Used in th e E l e c tr o ly s is
—10 ~
o b ta in e d co v ered more th a n th e p r a c t i c a l ran g e o f th e p ro c e s s as w i l l
be d is c u s s e d s u b s e q u e n tly .
I n p a s s in g , i t m ight be m entioned t h a t th e
r i p p l e i n th e o u tp u t v o lta g e o f th e d -c g e n e ra to r caused by th e f i e l d
r e c t i f i e r s a s shqwn on an o s c illo g r a p h , was ap p ro x im a te ly e q u a l i n mag­
n itu d e to th e in h e r e n t r i p p l e caused by th e commutator o f th e d—c gen­
e ra to r,
Thus, a low r i p p l e f a c t o r v o lta g e was m a in ta in e d f o r th e e -
I e c t r o I y s i s . ■ The e l e c t r i c a l s e t u p .i s shown d ia g ra m m a tic a lly i n F ig ­
u re I 0
2»
E l e c t r o l y t i c C o n ta in e r and E x te rn a l H eat Supply
In o r d e r to m a in ta in th e e l e c t r o l y t e a t ab o u t 93° C. d u rin g e x p e r i­
m e n ta l r u n s , i t was n e c e s s a ry to h e a t th e c e l l s by an e x te r n a l means.
'
T his was accom plished by u s in g a h o t p l a t e o f
w a tts c a p a c ity u n d er­
n e a th each e l e c t r o l y t e c o n ta i n e r .
C o n seq u en tly , th e e l e c t r o l y t e con­
t a i n e r was made o f py rex w ith dim en sio n s a s fo llo w s s, 6 in c h d ia m e te r by
11 3A
in c h h e ig h t w ith a p p ro x im a te ly 3900 c u b ic c e n tim e te rs -u seab le V ol-' :
•
ume,
’
>
'
W ith t h i s a rran g em en t, h e a t c o u ld be a p p lie d d i r e c t l y to th e c e l l and
c o n tr o lle d by two m ethods.
One c o n tr o l was by means o f th e low -m edium -high
sw itc h on th e h o t p l a t e , and th e o th e r c o n tr o l was th ro u g h v a r ia c s to w hich
th e h o t p l a t e s w ere e l e c t r i c a l l y c o n n e c te d .
W ith th e p y re x c o n ta in e r
p la c e d d i r e c t l y on th e h o t p l a t e , th e u n i t was p la c e d on a c e l l t a b l e s
A tta ch e d to th e ta b le was a c e l l ra c k w hich se rv e d as a te r m in a l b o ard
f o r e l e c t r i c a l c o n n e c tio n s and a ls o p re v e n te d th e p y rex c o n ta in e r from
any h o r iz o n ta l movement w hich w ould cau se th e c o n ta in e r to s l i p from th e
hot p la te e
“ IX —
■.
3»
-
E le c tro d e s and E le c tro d e S u p p o rts
I n a l l th e e x p e rim e n ta l ru n s one ty p e o f e le c tr o d e h o ld e r was used,,
The e le c tr o d e h o ld e r was made from a l / h in c h s h e e t o f p o ly s ty re n e
w hich i s r e s i s t a n t to s u lp h u r ic a c id .
The o u ts id e dim ensions o f th e
. p o ly s ty re n e h o ld e r a re l i 'in c h e s by 8 in c h e s w ith s l o t s p ro v id e d f o r th e
p lacem en t o f th e anode, c a th o d e , and a th erm o m eter.
To p re v e n t s lip p in g
th ro u g h th e s l o t s , th e anode, cath o d e and therm om eter i n each e le c tro d e
h o ld e r w ere clam ped i n p la c e .
W ith e le c tr o d e s and therm om eter clamped
to th e e le c tr o d e h o ld e r, th e u n i t was p la c e d d i r e c t l y on th e p y rex con­
t a i n e r i n su ch a manner t h a t th e anode, c ath o d e , and therm om eter ex ten d ed
i n t o th e e l e c t r o l y t e .
p y re x c o n ta in e r .
The e le c tr o d e h o ld e r r e s t e d on th e to p rim o f th e
I t was th e n a sim ple m a tte r to make e l e c t r i c a l connec­
tio n s to th e te r m in a l b o a rd .
I n a l l th e e x p e rim e n ta l r u n s , th e c ath o d e was made from a chem ical
le a d s h e e t l / l 6 in c h e s th i c k w ith dim ensions such t h a t th e cathode,.’a re a
was a p p ro x im a te ly tw ic e th e anode a r e a .
To in s u r e p l a t i n g on b o th s id e s
o f th e anode, a c ath o d e was p la c e d on e ac h s id e o f th e anode; th e t o t a l
cathode a r e a b e in g tw ic e th e anode a r e a .
A v a ila b le f o r r e s e a r c h w ere two ty p e s o f an o d es.
The f i r s t anode
u se d , i n ru n s Carbon I th ro u g h Carbon 6 , was a h ard carb o n ro d , 7/8 in c h
i n d ia m e te r.
I t i s b e lie v e d t h a t t h i s p a r t i c u l a r ty p e o f anode was used
in "arc lig h ts " .
At any r a t e , th e anodes o f t h i s ty p e p ro v ed o f no im­
p o rta n c e s in c e th e y d id n o t p ro v id e s a t i s f a c t o r y r e s u l t s .
The second
ty p e o f anode u sed was an "Acheson G ra p h ite " o f grade A.G.R. as d e sig n a te d
-1 2
-
by th e N a tio n a l Carbon Company« -This ty p e o f anode was u sed i n a l l ru n s
su b se q u e n t to Carbon 6„. The dim ensions o f th e anode u sed i n m ost ru n s
was 9 in c h e s by U in c h e s by l / 2 in c h .
I n some ru n s i t was n e c e s s a ry to
d e sig n th e anodes w ith a s m a lle r e f f e c t i v e a r e a .( a r e a submerged i n th e
e l e c t r o l y t e ) i n o r d e r to a c h ie v e h ig h c u r r e n t d e n s i t i e s .
To fin d th e
e f f e c t i v e a r e a , i n a l l c a s e s , th e a c t u a l c u r r e n t d iv id e d by th e c u r r e n t
d e n s it y w i l l g iv e th e e f f e c t i v e a r e a .
(See T able I f o r d a t a ) .
Acheson
G ra p h ite o f grade A. G. R. i s a much s o f t e r m a te r ia l th an th e f i r s t c a r­
bon ro d u se d .
T his s o f t m a te r ia l d id le n d i t s e l f to more s a t i s f a c t o r y
re s u lts .
Iu
D rying Oven
I t was found c o n v e n ie n t to u se a d ry in g oven to d e te rm in e th e dry,
w e ig h ts o f th e anodes b e fo re and a f t e r an e x p e rim e n ta l r u n .
th e g ra p h ite a b so rb s ab o u t 10 grams o f th e e l e c t r o l y t e .
I n g e n e ra l,
I n o r d e r to
d e term in e c u r r e n t e f f i c i e n c i e s , th e d ry w e ig h t o f th e anode was re c o rd e d
b e fo re a ru n ; and a t th e end o f th e r u n , th e anode p lu s manganese d io x id e
was d r ie d i n th e oven a t a te m p e ra tu re o f a b o u t 80-85
re c o rd e d .
C ., and th e w eig h t
By s u b tr a c ti n g th e d ry w e ig h t o f th e anode b e fo re a ru n from
th e d ry w e ig h t p f th e anode fo llo w in g th e r u n , th e manganese d io x id e de­
p o s i t was determined®
/
" 13 “
B.
PROCEDURE'
The p ro c e d u re fo llo w e d i n p ro d u c in g b a t t e r y a c tiv e manganese d io x id e
from manganese b e a rin g o re can be summarized i n th r e e s te p s :
t i o n o f th e E l e c t r o l y t e .
1.
(2)
The E l e c t r o l y s i s .
( l ) P re p a ra ­
(3) ' Anode S tr ip p in g .
P r e p a r a tio n o f th e E l e c t r o l y t e '
B r i e f l y 5 i t was r e q u ir e d t h a t th e manganese b e a rin g o re be p u t in to
a manganese s u lp h a te s o lu tio n w ith c e r t a i n c o n c e n tra tio n s o f manganese.
I n th e p ro c e s s o f o b ta in in g th e manganese s u lp h a te , s u lp h u ric a c id was
em ployed.
The f i n a l s o l u t i o n c o n ta in in g manganese s u lp h a te and s u lp h u ric
a c id c b n s t i t u t e d th e e l e c t r o l y t e .
The e lim in a tio n o f im p u r itie s and th e
a c tu a l p r e p a r a tio n o f th e e l e c t r o l y t e f o r v a rio u s c o n d itio n s i s d i s Qtibsed i n d e t a i l i n th e c h e m ic a l. e n g in e e rin g t h e s i s on t h i s r e s e a r c h * ^
2.
EIe c t r o l y s i s '
The e l e c t r o l y s i s i t s e l f was perform ed by p a s s in g a p r e s c r ib e d
amount o f c u r r e n t th ro u g h th e e l e c t r o l y t e by means of. th e e le c tr o d e s .
However5 c e r t a i n c h ro n o lo g ic a l s te p s m ust be ta k e n i n th e e l e c t r o l y s i s
p ro c e ss.
W ith p y rex c o n ta in e rs f i l l e d to a p re s c r ib e d volume o f e le c ­
t r o l y t e , th e h o t p l a t e s w ere tu rn e d on a llo w in g th e e le c tr o ly te - to a t ­
t a i n a te m p e ra tu re o f ab o u t 93° C.
th e e l e c t r o l y t e re a c h e d 93
O
T h is to o k a p p ro x im a te ly 2 h o u rs .
When
C. t h e - c e l l h o ld e r , com plete w ith anode, c a th ­
ode, and therm om eter was p la c e d i n th e c e l l and co n n ected e l e c t r i c a l l y to
th e d -c g e n e r a to r .
B efore s t a r t i n g th e g e n e ra to r., i t was n e c e s s a ry to
allo w a b o u t 2 m in u tes f o r th e e l e c t r o n i c tu b e s i n th e r e c t i f i e r c i r c u i t
to warm up.
A f te r s t a r t i n g th e g e n e r a to r , th e c o n tr o l v a r ia c i n th e
r e c t i f i e r c i r c u i t was v a r ie d u n t i l t h e , am m eter.in d ic a te d an ap p o in ted
amount o f c u r r e n t p a s s in g th ro u g h th e c e ll s #
. W hile e l e c t r o l y s i s was ta k in g p la c e , i t was n e c e s s a ry to r e p la c e
th e s p e n t e l e c t r o l y t e p e r i o d i c a l l y w ith f r e s h s o lu tio n o f n e u t r a l man­
ganese s u lp h a te « A t th e same tim e , th e s u lp h u ric a c id g e n e ra te d was
w ithdraw n i n p ro p e r amounts „
The amount o f f r e s h s o lu tio n added and th e
amount o f a c id removed i s co v ered i n d e t a i l i n th e ch em ical e n g in e e rin g
th e s is .
D uring th e e x p e rim e n ta l ru n s , th e changing o f s o lu tio n was p e r ­
formed e v e ry 1 /2 h our o r e v ery hour- depending on th e q u a n tity added and
removed.
I t has been th e p r a c t i c e i n th e r e s e a r c h d u rin g th e p a s t y e a r
to average th e v o lta g e and c u r r e n t re a d in g f o r th e p e rio d betw een r e ­
p le n ish m e n t o f th e s p e n t e le c t r o l y t e #
When s to p p in g a ru n th e c o n tr o l v a r ia c was changed u n t i l th e ammeter
re a d in g was z e r o # When th e ammeter re a d z e ro , i t was th e n s a f e to d is ­
co n n ect th e c e l l s and remove th e e le c tr o d e s from th e e le c t r o l y t e #
3.
Anode S tr ip p in g
The method used i n th e p a s t by o th e r e x p e rim e n te rs to remove th e
manganese d io x id e from th e anode was sim ply by s c ra p in g th e anode w ith,
a wood c h i s e l .'
T his was a most u n s a ti s f a c to r y o p e ra tio n , b ecau se th e ^
ad h eren ce o f th e manganese dioxi. de to th e g ra p h ite anode i s o f such
s tr e n g th t h a t rem oval o f th e manganese d io x id e w ith o u t g r a p h i t e c o n te n t
was p r a c t i c a l l y im p o s s ib le . - A lso , t h i s was a r a t h e r te d io u s p ro cess#
I t was' fo u n d , d u rin g t h i s r e s e a r c h , t h a t i f th e anodes w ere b o ile d i n th e
e l e c t r o l y t e w h ile s t i l l i n th e e le c tr o d e h o ld e r w ith th e c a th o d e s , th e
manganese d io x id e , a f t e r a m a tte r o f U to 5 hours tim e , became lo o s e a t
th e s u rfa c e o f th e a n o d es.
This .was due to th e s o fte p in g o f th e anodes®
However, th e s o f te n in g occurs, on th e s u r f a c e o f th e anodes o n ly , and does
n o t p re v e n t f u r t h e r u se o f th e anod es.
S in c e carbon i s mixed w ith man­
ganese d io x id e i n p r e p a r a tio n f o r d ry c e l l b a t t e r i e s , th e carbon im p u rity
was n o t c o n sid e re d d e tr im e n ta l.
I p f a c t , A.G.R. g rq h ite has been found
to be s u p e r io r f o r d ry c e l l b a t t e r y use*
• , “ '16 «=
C,
OBSERVATIONS AND RESULTS
I n o r d e r to det'erm ine th e ty p e 6f e l e c t r i c a l lo a d in v o lv e d i n th e
p ro d u c tio n o f b a t t e r y a c tiv e manganese d io x id e from l o c a l o r e s , i t was
'
n e c e s s a ry to e s t a b l i s h th e range o f p r a c t i c a l o p e ra tin g c o n d itio n s „ A
s e r i e s o f r u n s , d e s ig n a te d Carbon I th ro u g h Carbon 2 1 , w ere perform ed
f o r t h a t p u rp o s e .
The e s s e n t i a l d a ta has been p la c e d on c u rv es and
ta b le s w hich s h a l l be r e f e r r e d to th ro u g h o u t th e fo llo w in g d is c u s s io n .
Whenever p o s s i b l e , t h e o r e t i c a l c o n s id e r a tio n w i l l be g iv en alo n g w ith
■th e d is c u s s io n .
T hat i s , some o f th e phenomena i n t h i s e l e c t r o l y t i c
p ro c e ss was n o t f u l l y u n d e rs to o d .
For in s ta n c e , why, when under th e
same c o n d itio n s .and when b o th anodes a r e good e l e c t r i c a l c o n d u c to rs,
does one anode m a te r ia l le n d i t s e l f to th e p ro c e ss v e ry w e ll, w h ile
.
a n o th e r w i l l n o t .
A nother phenomenon i s th e f a c t t h a t e l e c t r o l y t i c
manganese d io x i d e .i s n o t a co n d u cto r o f e l e c t r i c i t y when p ro d u ced a t
c e l l v o lta g e o v e r 1 ,7 v o l t s ( 1|.)$ and y e t , a c u r r e n t was p a s s e d through
th e c e l l s w ith ab o u t th e same v o lta g e r e q u ir e d w ith and w ith o u t a man­
ganese d io x id e p l a t i n g on th e an o d e.
Does t h i s mean t h a t , . a s G0W,
N ic h o ls con clu d ed , th e p l a t i n g could o n ly ta k e p la c e u n d e rn e a th th e
manganese d io x id e c o a tin g ? ( 2 ) ,
For th e p u rp o se o f e s t a b l i s h i n g th e
c h a r a c t e r i s t i c s o f th e e l e c t r i c a l lo a d , th e u n d e rs ta n d in g o f such ac­
t i o n i s o f seco n d ary im p o rtan ce i n t h i s t h e s i s ,
I.
E le c tro d e S t a b i l i t y
Much more w ork has been done on th e problem o f f in d in g a s u ita b le
anode th a n i s p re s e n te d h e r e .
However5 to show th e e f f e c t s o f d i f f e r e n t
ty p e s o f anode m a te r ia l on th e e l e c t r o l y t i c p r o c e s s , b o th ty p e s o f anodes
u sed i n t h i s r e s e a r c h w i l l be d is c u s s e d , a lth o u g h th e r e s u l t s w ith th e
h a rd carbon ro d anode w ere f a r i n f e r i o r to th e A.G.R. g r a p h ite -anode
re s u lts .
A more com plete l i s t o f anodes t r i e d w i l l 'b e found i n th e
r e f e r e n c e s , m ain ly i n th e G eorgia I n s t i t u t e o f Technology ( 3 ) re p o rt .
and th e p u b lic a tio n by D r. P e te r Marx ( 2 ) .
I t i s i n t e r e s t i n g to note- t h a t S to r e y , S te in h o f f and H off (k ) .
found t h a t i f f o r g r a p h ite anodes th e p o t e n t i a l drop a c ro s s th e c e l l
was k e p t below th e d eco m p o sitio n p o t e n t i a l o f w a te r a c i d i f i e d w ith
s u lp h u r ic a c id ( a p p ro x im a te ly 1 .7 v o l t s ) , th e r e would be no d e te r io r a ­
t i o n o f th e anodes.
However,' t h i s i s im p r a c tic a l f o r a com m ercial
o p e r a tio n .
a.
Anodes
The c h ie f f a c t o r a f f e c t in g th e anodes i s c u r r e n t d e n s ity .
F o r th e h a rd carbon anodes, c u r r e n t d e n s i t i e s o f Ii3=60 a m p s . / f t . ^
caused so much d e t e r i o r a t i o n to th e anodes t h a t th e e l e c t r o l y t e
became opaque from suspended carb o n - a f te r -as l i t t l e as '3 hours
o f ru n tim e..
The A.G.R. g r a p h ite anodes d id not. undergo d e te r ­
i o r a t i o n to such a d e g re e .
When-A.G.R. g ra p h ite anodes w ere used
w ith 39' a m p s /f t. 2 c u r r e n t d e n s ity and 3 ho u rs o f ru n tim e , th e
e l e c t r o l y t e was alm o st t o t a l l y c l e a r o f suspended c a rb o n .
The
d e t e r i o r a t i o n a t t h i s c u r r e n t d e n s it y seemed s l i g h t , a s o n ly a
s m a ll amount o f carbon was found on th e bottom o f ' th e e l e c t r o l y t e
c o n ta in e r .
T his amount was an e s tim a te d 1 /2 gram o r l e s s . ■
- 18 A lthough Van A rsd ale and M aier (£) d id n o t m entiqn any anode d e te r ­
i o r a t i o n f o r c u r r e n t d e n s it ie s up to 30 a m p s ,/ f t . 2 u sin g AeGiRe
g r a p h ite anodes, th e G eorgia I n s t i t u t e Of Technology (3 ) d id f in d
c o n s id e ra b le damage to A0GeRe g ra p h ite abodes a f t e r lo n g p e rio d s o f
o p e r a tio n ( 30-75 hours a t c u r r e n t d e n s i t i e s o f above 20 a n p s0/ f t 0^ ) 0
The a c id c o n c e n tr a tio n caused some anode d e t e r i o r a t i o n , b u t
n o t to such an e x te n t 'as d id th e c u r r e n t d e n s ity .
I n ru n Carbon 15,
C e ll 3 a d is c o l o r a t io n o f th e . e l e c t r o l y t e was n o tic e d a f t e r ab o u t 10
ho urs o f o p e r a tio n .
The amount o f suspended -carb o n was s t i l l n o t
enough to cause concern a f t e r 15 ho u rs o f o p e ra tio n *
T em perature seemed to be th e cau se o f s e r io u s anode d e t e r i o r a ­
tio n .
F o r ru n Carbon 6 , C e lls I , 2, 3, and k , th e d e c re a se d tem­
p e r a tu r e s caused much anode d e t e r i o r a t i o n w ith o th e r f a c t o r s r e ­
m aining c o n s ta n t.
I n f a c t , a t i|0° C. c e l l te m p e ratu re th e anode 1
was a tta c k e d to .s u c h a d e g re e t h a t la r g e s u rfa c e s o f th e h a rd c a r ­
bon rod anode w ere d em olished.
Under th e same c o n d itio n s , a t a tem­
p e r a tu r e o f 92° C ,, th e anode d id n o t undergo such in te n s e d e s tr u c ­
tio n ,
S in ce i t i s n o t a d v isa b le to o p e ra te a t low te m p e ra tu re s (see
"Anode. C u rre n t E f f i c i e n c i e s and Kw-Hr p e r Pound MnOgs" " C e ll Tem­
p e r a t u r e s ." ) ■ th is , d e tr im e n ta l a c tio n may be e lim in a te d *
b.
Cathode
I n a l l th e e x p e rim e n ta l ru n s ch em ical le a d was used as th e c a th ­
o d e,
The chem ical le a d r e s i s t e d s u lp h u ric acic| r e a c t i o n , and was n o t
a f f e c t e d by th e c u r r e n t d e n s ity . ' I n th e e l e c t r o l y t i c p ro c e ss th e chem ical
le a d c ath o d e a c te d as a 100 p e r c e n t l i b e r a t o r o f hydrogen»
2e
C e ll V o ltag es
. D uring th e e x p e rim e n ta l ru n s th e av erag e v o lta g e p e r c e l l was o b ta in e d
and p l o t t e d a lo n g w ith th e c u rv e s o f c u r r e n t e f f i c i e n c i e s ' and- "icw-hr p e r'
pound MhOg.
The v o lta g e s w ere o b ta in e d d i r e c t l y from th e anodes t o e lim ­
in a t e te r m in a l c o n ta c t p o t e n t i a l drop and IR drop th ro u g h th e e l e c t r i c a l
c o n n ectio n a s s o c ia te d w ith th e C e l l s 0 'A ls o ? th e v o lta g e s p e r c e l l were
av erag ed o v e r an e n t i r e ru n .
I t was found t h a t a f t e r stopping, th e e le c ­
t r o l y s i s , a back v o lta g e o f about l e5> v o l t s e x is te d f o r a s h o r t d u ra tio n
(a b o u t 5 m in u tes) and th e n dropped to a v a lu e o f ab o u t 0„7 v o l t s 0
ae
Anode C u rre n t D e n sity
An in c re a s e d a v erag e v o lta g e p e r c e l l was e x p e rie n c e d w ith an
in c r e a s e i n c u r r e n t d e n s it y .
The v o lta g e in c r e a s e i s ap p ro x im ately
l i n e a r i n th e range o f from 1*^8 v o lts a t a c u r r e n t d e n s it y o f 3„37
amps . / f t . 2 to 2 *5)6 v o l t s a t 39 a m p s « /ft*2 w ith th e g r a p h ite anodes.
T his i s i n d ic a te d i n F ig u re 2*
b.
E l e c t r o l y t e A c id ity
W ith in th e u s e f u l ran g e o f a c i d i t y , th e re was no v a r ia tio n in
th e average v o lta g e p e r c e l l ; o th e r f a c t o r s h e ld c o n s ta n t.
A s lig h t
v o lta g e in c re a s e , o c cu red f o r a c id i tie s betw een 33o5> and 6? g n i./l. HgSO^0 .
The v a lu e o f th e v o lta g e a t 6? g m ./l. was found to be 1 .9 v o l t s ; and
-
20
-
a t 33. 5 gme/ l . th e v a lu e o f th e v o lta g e was 2 .0 v o l t s .
B oth v a lu e s
- /
w ere ta k e n fro m .ru n s w here th e c u r r e n t d e n s ity was 10 a m p s ./ f t .^ ,
as shoim i n F ig u re 3 .
c.
E l e c t r o l y t e Manganese S u lp h a te C o n c e n tra tio n s
The av erag e v o lta g e p e r c e l l was n o t a f f e c t e d by a change i n
manganese s u lp h a te c o n c e n tr a tio n .
For th e e n t i r e range o f manganese
c o n c e n tra tio n s p l o t t e d i n F ig u re k s i . e . , 100 to 1?6 g m ./l. MnSO^,
th e v o lta g e was 1 .875
0 .0 2 5 v o lts u n d er th e c o n d itio n s g iv en i n
F ig u re Uo
d.
Anode to Cathode S pacing
As w o uld be e x p e c te d , an in c r e a s e i n th e sp ac in g o f th e e le c tr o d e s
. caused a g r e a te r v o lta g e drop a c c e ss th e. c e l l w ith a l l o t h e r 'f a c t o r s '
b e in g h e ld c o n s ta n t.
T h is v o lta g e drop was due to th e lo n g e r c u rrd p t,
p a th th ro u g h th e e l e c t r o l y t e .
The av erag e v o lta g e drop o c c u rrin g a t
•
-
"•
.....
a sp a c in g o f 0 .U38 in c h was 1 .7 1 v o l t s , and a t a sp acin g p.f 1 <s'75 in c h e s
.
th e v o lta g e drop Was I . $2 v o l t s .
3.
T his i s in d ic a te d i n F ig u re 5o ’
C u rre n t E f f i c i e n c i e s and Kw-Hr p e r Pound o f MnOp
The anode c u r r e n t e f f ic ie n c y i s th e r a t i o o f th e a c tu a l amount o f MnOg
p la te d on th e anode t o 't h e amount t h a t sh o u ld be p la te d on a c c o rd in g to.
F a ra d a y ’ s second law o f e l e c t r o l y s i s , i f a l l th e manganese combined w ith
oxygen to form MhOg.
t i o n i n th e c e l l s
To e x p la in t h i s f u r t h e r , c o n s id e r th e ch em ical ac­
MnSO^->■ 2 HgO = HgSO^ 4* Hg4-MnOg.
The manganese
changes v a le n c e from tw o, i n MnSO^ to f o u r , i n MnOg, o r a t o t a l change o f
I
'
.
-
v a le n c e o f two..
21
-
The hydrogen i s given o f f a t th e cath o d e, and th e MnO2
i s , o f c o u rs e , p la te d on th e anode.
Now th e n , F a ra d a y 's law s t a t e s t h a t
th e w e ig h t o f a m e ta l d e p o s ite d , o r o f a gas s e t f r e e by an e l e c t r o l y t i c
p ro c e ss, i s d i r e c t l y p r o p o r tio n a l to th e g ra m -e q u iv a len t w e ig h t o f th e
m e ta l o r g a s5 and t h a t 965UO coulombs w i l l d e p o s its m e ta l o r s e t o f f gas
to th e amount o f one g ra m -e q u iv a le n t w e ig h t.
I n e q u a tio n form th e law
i s a s fo llo w s :
m = qw
9& h0 n
w here m i s th e w e ig h t i n grams o f th e m e ta l d e p o s ite d , o r o f th e
gas s e t f r e e ,
q i s th e q u a n tity o f e l e c t r i c i t y i n coulombs p a s s in g th ro u g h
th e e l e c t r o l y t e .
w i s th e atom ic w e ig h t o f th e m a te r ia l d e p o s ite d , o r s e t f r e e .
n i s th e v a le n c e o f th e m a t e r i a l .
U sing a v a le n c e change o f two and th e atom ic w eig h t o f Mn as 5U»93, and
th e atom ic w e ig h t o f O2 as 32, th e t h e o r e t i c a l d e p o s its o f MnO2 i s , a c - .
c o rd in g to F a ra d a y 's Laws
m = q .x 86,93
96^UO x 2
■
‘
Gm. MnO2
and q - hours x 3600 x amperes
t h e r e f o r e , m = hours x 3600 x amperes x 86,93
96^0 x 2
m = (1 ,6 2 x amperes x h o u rs ) Gm. MnO2
-
22
-
andj f i n a l l y , the c u rre n t e f f i c i e n c y i s :
c u r r e n t e f f ic ie n c y = a c tu a l w eig h t o f MhO9 d e p o s ite d i n grams x 100
1 ,6 2 x amperes x hours
D ir e c tly r e l a t e d to th e c u r r e n t e f f i c i e n c i e s i s th e Kw-=Hr p e r pound
o f MnO0 .
To show th e method u sed i n c a l c u l a t i n g t h i s from the d a ta g iv en
on T ab le I , a s p e c i f i c exam ple, ru n Carbon 12 from Table I , w i l l be. ta k e n
as fo llo w s :
A verage v o lts p e r c e l l . . . . . . . .
i
. 1,8 0
Grams MnOg p ro d u c e d . . . . . , . . . . . . . I .
.6 0 ,5
A c tu a l c u r r e n t . . . . . . . . . . . . . . . . .
3o
Hours o f r u n . . . . . . . . . . . . o . . .
* * IT o2 ^
Kw-Hr = 1 ,8 0 x 3»72 x 17,23
1000
Pounds MnO0 = 60,6
2 ' ~W l
Kw-Hr p e r pound MnO z 1 ,8 0 x 3*72 x 17,25) x h&h - 0 ,8 6 5
,
^
6 0 ,5 x 1000
I t sh o u ld be m entioned t h a t s in c e th e a v erag e v o lta g e p e r c e l l was
ta k e n d i r e c t l y from th e an o d es, th e power re q u ire m e n ts f o r a commer­
c i a l p ro c e ss w ould be s l i g h t l y g r e a t e r depending on th e te r m in a l v o l­
ta g e drop and IR v o lta g e d ro p ,th ro u g h th e a s s o c ia te d e l e c t r i c a l conn e c tio n s .
I n th e case o f b o th c u rre n t e f f i c i e n c i e s and Kw-Hr p e r
pound MnOg th e v a lu e s g iv e n i n ' Table I a r e u n c o rre c te d f o r im p u r itie s .
The e r r o r in tro d u c e d i p c u r r e n t e f f i c i e n c i e s and Kw-Hr p e r pound MnOg
w ould n o t be s e r io u s s in c e th e im p u r itie s c o n s itu te a sm aH p ercen tag e
o f th e an o d ic d e p o s i t s .
I t i s i n t e r e s t i n g to n o te t h a t a c c o rd in g to Kameyama and I I d a
—23 “
( m e ta llb o rs e 1932, p« 1183) i t i s p o s s i b l e , by use o f a l t e r n a t i n g c u r­
r e n t , to o b ta in a d ry c e l l MnO2 i f th e MnSO^ i s decomposed a t th e h ig h e r
te m p e ra tu re s .
T his was t r i e d by P e te r Marx (2 ) w ith p la tin u m gauze
e le c tr o d e s having an e le c tr o d e s u r f a c e o f 2 cm. 2
The o n ly r e s u l t given
was t h a t w ith a c u r r e n t d e n s ity of £0 amp./dm. 2 (ab o u t U63 a m p s /f t.2 )
and a v o lta g e o f about 20—25 v o l t s , the power consum ption was u n reaso n ­
a b ly h ig h i n com parison to t h e use o f d i r e c t c u r r e n t,
a.
Anode C u rre n t D e n sity
-
The d a ta o b ta in e d f o r th e v a r i a t i o n o f c u r r e n t d e n s ity w ith
e l e c t r o l y t e c o n c e n tra tio n s o f 6? g m ./l. H^SO^ and 137<>£ g m ./l.
MnSO^, e le c tr o d e s p a c in g o f I in c h , te m p e ra tu re o f 93° C ., has
been p l o t t e d i n F ig u re 2 .
E xam ination o f th e curve o f c u r r e n t
e f f i c i e n c i e s i n d ic a te s a maximum e f f i c i e n c y o f ab o u t 6 3 .7 p e r
c e n t, o c c u rrin g a t a c u r r e n t d e n s ity o f 6.72 a m p s /ft. 2
The en­
e rg y r e q u ir e d to produce a pound o f MnO2 a t th is ; c u r r e n t d e n s ity
i s O068I1 Kw-Hr p e r pound MhO2 .
At lo w er c u rre n t, d e n s i t i e s , be­
low £ a m p s i / f t .2 , th e c u r r e n t e f f ic ie n c ie s - drop r a p id ly , and th e
en erg y re q u ire m e n t in c r e a s e s so r a p id ly t h a t t h i s m ight w e ll be
c a lle d th e c u to f f p o in t o f th e e l e c t r o l y s i s f o r a l l p r a c t i c a l .
p u rp o s e s .
F o r c u r r e n t d e n s i t i e s above 6.72 a m p s ./ f t. 2 th e c u r -
r e n t e f f i c i e n c i e s and Kw-Hr p e r pound MnO2 have a more g ra d u a l
in c r e a s e and d e c re a se r e s p e c tiv e ly , up to a c u rre n t d e n s ity o f
about 20 .a m p s ./f t. 2
Beyond t h i s p o i n t , th e e l e c t r o l y s i s be­
comes im p r a c tic a l f o r two re a s o n s :
( l ) th e energy re q u ire m e n t
becomes e x c e s s iv e ly h ig h (a b o u t 2 .3 Kw-Hr f o r c u r r e n t d e n s ity o f
“ 21). “
39. a m p s/fto 2 ) (2)„
The anode d e t e r i o r a t i o n , n o t e v id e n t by i n ­
s p e c tio n o f th e c u rv e s, becomes e x c e s s iv e .
A lthough th e amount o f anode d e t e r i o r a t i o n i s r a t h e r d i f f i ­
c u l t to p r e d i c t , th e amount o f anode d e t e r i o r a t i o n found a f t e r
.5 ho u rs ru n tim e a t 39 a m p s , / f t c u r r e n t d e n sity ' was an estim a­
te d 1/2 gram found on th e bottom o f th e c e l l .
o c c u rre d when g r a p h ite anodes w ere u se d .
T his d e te r io r a tio n
W ith th e h a rd carb o n
ro d anodes, t h e d e t e r i o r a t i o n a t c u r r e n t d e n s i t i e s o f 1)5-60
a m p s ,/ f t.
was such th a t a f t e r about 10 h o u rs o f o p e ra tio n th e s e
anodes l o s t c o n s id e ra b le w e ig h t.
I n g e n e r a l, th e r e i s a l i m i t to th e c u r r e n t d e n s i t i e s u se a b le
f o r re a so n a b le c u r r e n t d e n s i t i e s and power re q u ire m e n ts .
The low er
l i m i t i s due to th e c u to ff p o in t o f th e e l e c t r o l y s i s , and th e upper
l i m i t i s d e p e n d e n t on th e ty p e o f anode u se d .
S in ce th e c u r r e n t e f f i c i e n c i e s a re governed by th e ampyhr o f
e l e c t r o l y s i s th e o n ly e s s e n t i a l d if f e r e n c e betw een c u r r e n t e f f i c i e n ­
c i e s and en erg y r e q u ir e d to produce a pound o f MnO0 i s i n t h e v o lta g e p e r c e ll , th e Kw-Hr p e r pound MnOg cu rv es fo llo w an in v e rs e
r e l a t i o n s h i p w ith c u r r e n t e f f i c i e n c i e s .
As d is c u s s e d u n d er wC e ll
V o lta g e s ," th e amount o f v o lta g e v a r i a t i o n i s sm all f o r most c a s e s ,
•and as a r e s u l t o f t h i s , th e l i n e a r i t y o f th e in v e rs e r e l a tio n s h ip
i s e v id e n t from F ig u re s 2 , 3S and I),
— 2J?
be
E l e c t r o l y t e A c id ity
As i n th e case o f c u r r e n t d e n s i t i e s th e e l e c t r o l y t e a c i d i t y
e f f e c t s th e c u r r e n t e f f i c i e n c i e s and energy re q u ire d i n a s im ila r
m annere
T hat i s , th e r e i s a c u to f f p o i n t , and a p o in t f o r maxi­
mum v a lu e s o f c u r r e n t e f f i c i e n c i e s .
As shown i n F ig u re 3 , w ith
an a c i d i t y o f ab o u t 95 g m ./l,
S
and th e fo llo w in g c o n d itio n s ;
2
137*5 gnio/lo MnSO^, 10 a m p s ./ f t e , I in c h e le c tr o d e sp a c in g ,
g ra p h ite anodes o f A.G.R. ty p e j th e maximum c u r r e n t e f f ic ie n c y i s
ab o u t 72 p e r c e n t, and th e e n erg y r e q u ir e d to produce a pound o f MnOg
i s found to b e 0 o-7Ul Kw-Hr6
The c u to f f p o in t due to th e e l e c t r o l y t e
a c i d i t y i s i n th e re g io n below 10 gm6/ l 6 HgSO^ f o r th e same condi­
tio n s as s t a t e d above,
The upper l i m i t o f a c i d i t y i s n o t d e fin ­
i t e l y e s ta b lis h e d j i t i s b e lie v e d t h a t th e anode d e t e r i o r a t i o n ,
as i n th e case o f c u r r e n t d e n s i t i e s , w i l l be th e d e te rm in in g f a c ­
tor.*
C6
T his i s b a se d on th e l i t e r a t u r e c o n s u lte d (U)e .
C e ll Tem perature
A ru n c a l l e d "Carbon 6U was made to d e term in e th e e f f e c t o f
c e l l te m p e ra tu re s on c u r r e n t e f f i c i e n c i e s and power re q u ire m e n ts „
A lthough t h i s ru n was made w ith th e. h a rd carbon ro d an o d es, where
a t b e s t o n ly 26 p e r c e n t e f f i c i e n c i e s w ere o b ta in e d , i t d em o n strates
th e f a c t t h a t th e p ro c e s s s h o u ld be co n d u cted w ith a h ig h tem pera­
tu re .
On ru n Carbon 6 n o t o n ly d id th e c u rre n t e f f i c i e n c i e s de­
c re a s e w ith low er te m p e ra tu re s , b u t a ls o th e abode d e t e r i o r a t i o n
-
26
*
was more s e v e re a t th e lo w e r te m p e ra tu re s 6 F o r I n s ta h c e 5 Van A rsd ale
and M aier (£) s t a t e d t h a t a h ig h e r te m p e ra tu re w i l l in c r e a s e th e speed
o f h y d ro ly s is so t h a t th e manganic s o lu tio n s do n o t have tim e to d i f ­
fu s e away from th e e le c tr o d e b e fo re b e in g decomposed; and t h a t the
r a p id b re a k in g -u p o f manganic s a l t s p re v e n ts f u r t h e r o x id a tio n r e s u l t ­
in g i n oxygen form ed.
I n a d d itio n to t h i s 5 G eorgia I n s t i t u t e o f Tech­
nology (3) found t h a t from th e numerous sam ples d e n t i n t o th e Army
S ig n a l Corps L a b o r a to r ie s 5 ru n s conducted above 80° Co p ro d u ced MnOg
t h a t was p r a c t i c a l l y a l l gamma p h a s e .
Lower te m p e ra tu re s gave a
m ix tu re o f gamma p h ase MnO2 and c ry p to m e la n e.
W ith th e s e r e s u l t s i n
m ind5 a l l ru n s from Carbon 7 th ro u g h Carbon 22 were conducted a t 93°
C .± 3° C.
d.
Anode M a te ria l
A lthough o n ly two ty p e s o f anodes w ere u sed i n th e e l e c t r o l y s i s
tp d ate h e re at-M ontana S ta te C o lle g e 5 th e c u r r e n t e f f i c i e n c i e s and
energy re q u ire m e n ts d em o n strate th e dependence o f e f f i c i e n t e l e c t r o l ­
y s i s on t h e ty p e o f anode u s e d .
F o r exam ples ru n Carbon I u sin g a
h a rd c a r to n anode a t l£, a m p s ./ f t . ^ 5 137o5> g m s ./l. MnSO^s 67 g m s ./l.
HgSO^5 91° C .5 had a c u r r e n t e f f ic ie n c y o f 23 p e r c e n t5 and energy
r e q u ir e d was- 2 . If? Kw-Hr p e r pound MnO2 ; w h ile ru n Carbon IB 5 C e ll 2
u sin g A.G.R. g r a p h ite anode a t 18.6 amps . / f t . ^ 5 137.5: g m s ./l. MnS0 , 5
67 g m s ./l. H2SOjj5 93° C .5 had a c u r r e n t e f f ic ie n c y ,of 3L p e r c e n t5
and th e e n erg y re q u ire m e n t was 0 .9 0 6 Kw-Hr p e r pound ^MnOg.. - Accord­
= 27 —
in g to th e chem ical e q u a tio n o f th e e l e c t r o l y s i s s i t w ould' ap p ear as
i f e i t h e r anode w ould prove s a t i s f a c t o r y , i . e . , s in c e th e prim e
re a so n f o r th e anode i s to p ro v id e a p a th f o r th e c u r r e n t th ro u g h
th e c e l l s , and b o th ty p e s o f anodes a re good co n d u cto rs o f e l e c t r i c ­
i t y , th e e l e c t r o l y s i s sh o u ld n o t be e f f e c t e d by th e ty p e o f e l e c t r i ­
c a l c o n d u cto r u s e d .
Because th e r e i s a g r e a t d if f e r e n c e i n th e r e ­
s u l t s o f th e two ty p e s o f anodes u sed j i t would seem l o g i c a l to a t ­
t r i b u t e t h i s in c o n s is te n c y to th e m ic ro sc o p ic s u rfa c e s o f th e anodes,
e.
E l e c tr o ly te Manganese S u lp h a te C o n c e n tra tio n
W ith a c u r r e n t d e n s ity o f 10 a m p s ,/ f t., , e l e c t r o l y t e a c i d i t y o f
67 g m s ./l. H^SO^, 93° C ., i t was found t h a t a maximum c u r r e n t e f f i c ­
ie n c y o f 73oil p e r c e n t e x i s t e d w ith a en erg y re q u ire m e n t o f 0,735
J-" / '.
Kw-Hr p e r pound MnO2 , f o r MhSO^ c o n c e n tra tio n o f 1^0 g m ./l. A l­
though th e current, e f f i c i e n c i e s v a r ie d from k3 p e r c e n t to 7 3 .Ii . -„
'
p e r c e n t, th e Kw-Hr p e r pound MnO^ v a r ie d from 1 .2 3 to 0 .7 3 5 , and
f o r th e modt p a r t rem ained i n th e neighborhood o f about 0 .9 Kw-Hr p e r
pound MnOg.
f.
T his i s shown i n F ig u re It.
Anode to Cathode S p acin g
I t was found t h a t in c r e a s e d sp a c in g from cathode to anode gave
a s l i g h t l y in c r e a s e d c u r r e n t e f f i c i e n c y (from 52 p e r c e n t a t O .l^S
,.inches to 5 8 ,8 p e r c en t .a t 1 .7 5 in c h e s .)
Because o f th e in c re a s e d
v o lta g e p e r c e l l , th e en erg y re q u ire m e n t d id n o t change f o r th e spac­
in g o f O .I1.38 in c h e s to 1 .7 5 in c h e s , b u t rem ained a t 0 .9 0 Kw-Hr p e r
■= 28 <=>
pound MnO^0
%t would seem t h a t f o r the same energy re q u ire m e n t a
l a r g e r sp a c in g o f e le c tr o d e s sh o u ld be u sed to u t i l i z e th e in c re a s e d
c u r r e n t e f f ic ie n c y ; however, i f th e g r e a t e r amount o f c e l l space i s
. c o n s id e re d .o n a la r g e s c a l e ' o p e r a tio n , th e advantage o f in c re a s e d
c u r r e n t e f f i c i e n c i e s m ight be o v er b a la n c e d by th e c o s t o f f l o o r
space.
F ig u re S shows th e r e l a t i o n o f c u r r e n t e f f i c i e n c i e s and power
re q u ire m e n ts w ith e le c tr o d e s p a c in g s o f O0ItfS in c h e s , I in c h and 1 .7 5
in c h e s .
I f tim e would have perm itted, i t w o u ld have been i n t e r e s t i n g to
ex p erim en t on e le c tr o d e s p a c in g s le s s th a n OeItfS in c h e s a p a r t .
S in ce
e l e c t r o l y t i c MnO2 i s n o t a co n d u cto r o f e l e c t r i c i t y , once a p la tin g
was on th e an o d e, th e r e would be no d an g er o f s h o r t - c i r c u i t i n g the
anode and cathode e
-
h« E l e c t r o l y t i c MnO^ D ata
R eferen c e has a lr e a d y b e en made to Table I and th e a s s o c ia te d c u rv e s.
T able I has been p re p a re d d i r e c t l y from th e notebook u sed d u rin g th e r e ­
se a rc h ,
The n u m e ra l■s u p e r s c r i p t s ’ r e f e r to n o te s which a re l i s t e d on th e
page im m ed iately fo llo w in g T able I .
The c u rv e s given i n F ig u re s 2, 3,
I*, and 5 w ere c o n s tr u c te d d i r e c t l y from th e d a ta given i n T ab le I .
Table
I and graphs a re in c lu d e d on pages Ij-O to 5lo
5.
A n a ly sis o f E l e c t r o l y t i c MnO^
The chem ical a n a ly s is was made on c e r t a i n samples by th e F o r t Mon­
mouth L a b o r a to r ie s .
Table I I .
The r e s u l t s o f th e s e a n a ly se s have b een com piled i n
I n a l l c a se s w here a chem ical a n a ly s is was made th e s tr u c t u r e
- 29. o f MnO2 was found' to be "gamma p h a s e " „
to th e o th e r s a n p le s a n a ly z e d .
6«
Run Carbon 12 sample was s u p e r io r
T his i s shown i n Table T I,
R e s u lts o f B a tte r y P erform ance T e s ts
B a tte r y perform ance t e s t s w ere p e rfo rm ed on a -sample from ru n Car­
bon 7 by th e B a tte r y Branch o f th e S q u ie r S ig n a l L a b o r a to r ie s ,
s u l t o f th e i n i t i a l t e s t i s g iv e n i n T able I I I .
The r e ­
A lso , a ru n to be c a ll e d
"Carbon 22" w i l l h e n c e fo rth be com pleted to p ro v id e a b a t t e r y t e s t .
ru n w i l l be made under th e same c o n d itio n s a s e x is te d f o r Carbon 21.
The
P ro ­
v is io n w i l l be made to in c lu d e such d a ta i n t h i s t h e s i s when o b ta in a b le
under T able I I I 0
I t sh o u ld be n o te d t h a t th e o re from th e A fric a n Gold C o a st, when
made up i n t o a b a tte r y , and t e s t e d g iv e s a n A verage I n i t i a l S e rv ic e o f
ab o u t 8£ hours when d is c h a rg e d thro u g h 166 2 /5 ohms; w h ile Carbon 7
sample when u ndergoing a b a t t e r y t e s t d is c h a rg e th ro u g h 166 2 /3 ohms
g iv e s an Average I n i t i a l S e rv ic e o f 1 0 9 ,1 h o u rs , as shown i n T able I I I 0
T h is m a n ife s ts th e s u p e r i o r i t y i n t h i s r e s p e c t o f ru n Carbon 7 sample
to th e A fric a n o r e .
The s h e l f l i f e o f th e b a t t e r y made from th e sample
o f ru n Carbon 7 may o r may n o t compare to t h a t o f th e b a t t e r y made from
A fric a n o r e .
S ubsequent t e s t s by th e S q u ie r S ig n a l L a b o ra to rie s w i l l
d e term in e th e s h e l f l i f e o f th e b a t t e r y made from ru n Carbon 7 s a m p le ,.
-
III
30
^
■■.'," i'
COMMERCIAL APPLICABILITY OF ELECTRICAL LOAD CHARACTERISTICS
I n c a s e s w here e l e c t r i c energy r a n i s ''^ re b ased on a peak demand o f
e l e c t r i c a l lo a d , and w here . i t i s d e s ir a b le to have a h ig h lo a d f a c t o r ,
e l e c t r o l y t i c MnOg o f f e r s a t t r a c t i v e com m ercial p o s s i b i l i t i e s .
A lso ,
i n many c ase s th e r e i s s e a s o n a l power a v a il a b le t h a t co u ld v e ry w e ll
be u t i l i z e d . i n th e e l e c t r o l y t i c p r o d u c tio n .o f b a t t e r y a c ti v e Mn02 w ith ­
o u t r e d e s ig n o f 'th e e l e c t r o l y s i s a p p a r a tu s .
From th e e x p e rim e n ta l
d a ta th e o n ly s e r io u s ly u n d e s ir a b le f a c t o r i s th e la c k o f a s u ita b le
anode.
A lthough g ra p h ite anodes can be u sed up to a c u r r e n t d e n s ity
o f about 20 amps. / f t . 2 , i t w ould be e x p e d ie n t to have an anode t h a t
w ould n o t d e t e r i o r a t e u n d er h ig h c u r r e n t d e n s i t i e s so t h a t th e tim e
in v o le d i n th e e l e c t r o l y t i c p ro d u c tio n o f b a t t e r y a c tiv e MnOg co u ld
be m ost e f f i c i e n t l y u t i l i z e d .
A.
C u rre n t D e n sity
I n o rd e r to have a lo a d t h a t would be a p p lic a b le f o r o b ta in in g
a h ig h e l e c t r i c a l lo a d f a c t o r and re d u c ed power r a t e s on a p eak de­
mand b a s i s , th e e l e c t r i c a l lo a d w ould have to be r a t h e r f l e x i b l e .
To i l l u s t r a t e w h at i s m eant by th e f l e x i b i l i t y o f th e e l e c t r o l y t i c
lo a d i n p ro d u c in g b a t t e r y a c tiv e MnO , a s p e c if ic example w i l l be
2
g iv e n . I n th e exam ple, i t w i l l be assumed t h a t a c e l l room f o r th e
e l e c t r o l y s i s i s to be u se d h av in g th e .fo llo w in g designs'
Anode. . . . . .
.A .G .R. g r a p h ite w ith e f f e c t i v e a re a o f 15> f t . ^
C athodes . . . . .
.'Chemical le a d w ith e f f e c t i v e a re a o f I ^ f t . ^
E l e c t r o l y t e . . . .C o n c e n tra tio n s o f 6? g m /l. HoSOii and 137.5 g m /l.
MnSOli
4 ' ' ;
o
T em perature. . . .93 ■ C*
- 31 E le c tro d e s p a c in g . . . . . . .
I in c h
C e ll u n i t . ............................... . . 2 0 anodes and 21 cath o d es
Number o f c e l l u n i t s . . . . . . l l ;
C o n ta ct p o t e n t i a l . . . . . . .
Assumed to be 0 .3 0 v o l t s
I n a' 2k hour, p e r io d , th e e x p e c te d o u tp u t o f MnOg5 power r e q u ir e d , and
tim e to o b ta in a to n
o f MnOg based on th e e x p e rim e n ta l d a ta found on
th e curves o f F ig u re 2, w ith a c u r r e n t d e n s ity o f 10 a m p s ./ f t .2 would
be s
(10 x 1E>) amps x 1.62 gm MnO0 x 2k h r . x li* c e l l u n its x 20 anodes
_______ anodes
amp-hr
■
c e ll u n it „
k£h g m ./lb . ~
”
!
“ “
20^0 l b . Mn02 i n 2U h o u rs .
The power r e q u ir e d would be:
20^0 l b . x Q,o'9.06 Kw-Hr
' I b 0-MnO2
x 2 .1 8 = 2160 Kw-Hr f o r a 2h h r . p e r io d .
TTHH
w here th e q u a n tity 2 .1 8 allow s f o r a d d itio n a l power due to c o n ta c t
-TTHH
v o lta g e d ro p .
The tim e r e q u ir e d to produce a to n o f MnOg w ould be:
2000
2m
x 2i| s 23®lt h o u rs .
The c o s t o f en erg y a t l / h c e n t p e r Kw-Hr i s $ 3.27 p e r to n .
S in ce AGR
g r a p h ite anodes a re b ein g u s e d , a s a f e v a r i a t i o n i n th e c u r r e n t d e n s ity
w ould be from 5 a m p s . / f t . 2 to 1 8 .6 a m p s . / f t . T o show th e e f f e c t o f
v a r i a t i o n o f c u r r e n t d e n s ity th e v a lu e s u sed above w i l l be ta k e n as a
b ase f o r p e r u n i t v a lu e s , i . e 0, 10 a m p s . / f t . 2 co rresp o n d s to a p e r u n i t
c u r r e n t d e n s ity o f 1 .0 ; and so on f o r th e o th e r v a lu e s ab o v e.
S in ce the
—32 =»
extrem e c o n d itio n s o f f l e x i b i l i t y a re th e v a lu e s o f i n t e r e s t . T able
IV i s shown below?
TABLE IV.
C u rre n t
D e n s ity
F l e x i b i l i t y o f O utput and E l e c t r i c a l Load i n ' P e r U n it
V alues
O utput
o f MnOg
i n 2k h r .
E nergy R equired
For O utput o f
MnOg
Time R eq u ired
f o r to n o f
MnOg
C ost o f E le c - '
t r i c a l Energy
P e r Tbn o f MnOg
I
I
I
I
I
o ,5
O6ItUl ■'
0.177
2 ,2 5
1,0 7
1 ,8 6
1 ,765
2 ,l i t
0oUt5 .
1 .2 1
" In s p e c tio n ' o f T able IV I n d i c a t e s 't h a t th e lo a d ( en erg y r e q u i r e d f o r o u tp u t o f MnOg) may be v a r ie d from a p e r u n i t energy re q u ire m e n t
o f Ool;?? to 2elU w ith a v a r i a t i o n o f c o s t o f e l e c t r i c a l power p e r to n
MnOg i n p e r u n i t v a lu e s o f o n ly I „07 to I eB l0 ,In o th e r w ords, th e e l e c t r i c a l lo a d can be v a r ie d th ro u g h a w ide ran g e w ith o u t in c r e a s in g
to any a p p re c ia b le amount the power c o s t o f th e e l e c t r o l y s i s f o r a
u n i t w e ig h t o f MnOge
T his w ould be an im p o rta n t ite m , i f on a la r g e
s c a le o p e ra tio n th e e l e c t r i c i t y c o s t p e r month was b a se d on a peak
demand f o r t h a t m onth, , T hat i s , a t t h e tim e o f a n tic ip a te d peak d e -
•
mand, th e e l e c t r o l y s i s power re q u ire m e n t c o u ld be red u ced and th u s
save a c o n s id e ra b le amount o f power c o s t fo r . th e month.
C o n v erse ly ,
th e p ro d u c tio n c o u ld be in c r e a s e d when a s la c k p e rio d o f power de­
mand o c c u rre d and th u s th e lo a d f a c t o r o f an e l e c t r o l y s i s p l a n t could
be m a in ta in e d a t a h ig h e r v a lu e th a n i f t h i s p r a c tic e w ere n o t a d o p ted .
The a c t u a l v a lu e s in v o lv e d may be found by' m u ltip ly in g th e p e r
=" 33 u n i t v a lu e by th e b ase v a lu e s giv en i n th e p re v io u s c a lc u la tio n f o r c u r­
r e n t d e n s ity o f 10 amps. / f t , 2 .
The v a lu e s shown above a re v e ry c o n se rv a tiv e v a lu e s .
F o r in s ta n c e ,
as shown i n T able I f o r ru n s Carbon 1 3 , C e ll 3j Carbon lU , C e ll 2; Car­
bon 153 C e ll I j Carbon 20, C e ll I and Carbon 21, c u r r e n t e f f i c i e n c i e s o f
about 70 p e r c e n t a re o b ta in a b le u n d er c e r t a i n c o n d itio n s .
The c o n d itio n s
f o r ru n Carbon 21 w ere chosen from th e maximum c o n d itio n s as shown i n '
F ig u re s 2 , 3, and ij..
S in ce th e o th e r ru n s produced e f f i c i e n c i e s i n th e
re g io n o f 70 p e r c e n t th e optimum c o n d itio n s assumed from p re v io u s ex­
p e rim e n ts do n o t seem to be to o c r i t i c a l .
B.
ELECTROLYTE CONCENTRATIONS'
■ I n a com m ercial o p e r a tio n , th e e l e c t r o l y t e i s u s u a lly c o n tin u ­
o u s ly r e p le n is h e d w ith f r e s h s o lu tio n by a n a t u r a l g r a v ity flow from •
a s to r a g e ta n k .
A lso , i t i s u su ally th e p r a c t i c e to have th e d is c h a rg e
from one c e l l u n i t flow d i r e c t l y in to t h e n e x t, and so on, i n a s e r ­
i e s arrangem ent o f e l e c t r o l y t e flo w .
As a r e s u l t o f t h i s , th e concen­
t r a t i o n s o f th e f i r s t c e l l o f th e s e r ie s arran g em en t w i l l be d i f f e r ­
e n t from t h a t i n th e l a s t c e l l i n th e s e r i e s arrangem ent fo llo w in g
a p e rio d o f o p e r a tio n .
As F ig u re s 3 and U i n d i c a t e , th e c u r r e n t e f -
f ic ie n c y may be h e ld a t o r above £0 p e r c e n t w ith c o n c e n tra tio n v a r i ­
a tio n s o f 115 to 1?6 g m s /l. MnSO^ and 30 t o 130 g m s /l. HgSO,.
Thus
th e e l e c t r o l y s i s would n o t be .e f f e c te d s u b s t a n t i a l l y by th e d i f f e r ­
e n t e l e c t r o l y t e c o n c e n tra tio n s i n th e v a rio u s c e l l u n i t s 0
-
32
-
G0 POWER FAILURE
I n th e p ro d u c tio n o f e l e c t r o l y t i c manganese m e ta l ( 6 ) i t i s
n e c e s s a ry to p ro v id e an a u x ilia r y power su p p ly such as s to ra g e
b a t t e r i e s , i n e v en t o f power f a i l u r e , to keep th e manganese p la te d
on th e c a th o d e s from going back in to so lu tio n ®
I n th e c a se o f e -
l e c t r p l y t i c MnOg, th e p ro c e ss does n o t te n d to. gp in to r e v e r s e , ..
as in d ic a te d by th e e x p e rim e n ta l ,a-c e l e c t r o l y s i s t r i e d . b y P e te r
Marx (2 )„
A lso , numerous t r i a l s to remove th e MnO2 p l a t i n g by
b o ilin g an o d es, h aving an MnOg p l a t i n g , i n th e e l e c t r o l y t e w ere
a tte m p te d w ith o u t re d isso lv ih g th e MnO2 p l a t i n g .
T h e re fo re , i t
i s con clu d ed t h a t no a u x i l i a r y power su p p ly i s needed to p re v e n t
th e MnOg from r e tu r n in g to s o lu tio n i n e v e n t o f a power fa ilu re ®
t=» ^6 w
D.
ELECTRODE SPACING AND CELL SIZE
As m entioned p re v io u s ly ^ th e e l e c t r o l y t i c MnO0 produced a t v o lta g e s o v e r 1 .7 v o l t s i s a nonconductor o f e l e c t r i c i t y ; and s in c e
o p e r a tio n on a com m ercial b a s is w ould be above 1 .7 v o l t s s i t would
seem a d v is a b le to u se a c lo s e r sp a c in g o f e le c tr o d e s once th e anode
has a p l a t i n g o f MnO2 on i t s s u r f a c e .
To g iv e an id e a o f th e space
c o n s id e r a tio n in v o lv e d i n a c e l l u n i t o f th e ty p e u sed i n th e f o r e ­
going “C u rre n t D e n s ity " , suppose th e g ra p h ite anode was I in c h t h ic k ,
and th e c ath o d e 1 /8 in c h t h i c k .
Then, w ith a I in c h sp a c in g betw een
cath o d e and anode th e r e q u ir e d minimum le n g th o f th e c e l l u n i t would
be 5><,22 f e e t ; and s in c e th e c e l l u n i t w ould be ro u g h ly 3 f e e t w id e,
a minimum a r e a o f f l o o r space r e q u ir e d w ould be 13.66 f t . 2 .
However,
say th e sp ac in g betw een e le c tr o d e s was red u ced to 0 .3 in c h e s,, th e n
th e minimum a re a r e q u ir e d would be 1 0 .6 3 f t . ^ p e r c e l l u n i t ; o r a n e t
s a v in g o f f l o o r sp a c in g o f a b o u t 3 f t . .
S in c e a la r g e number o f
c e l l u n its would be r e q u ir e d i n a com m ercial o p e ra tio n , th e sav in g .,
i n f l o o r space would be a c a r d in a l p o i n t . ■
-
37
-
IV CONCLUSIONS
Under a number' o f v a rio u s c o n d itio n s th e c u rre n t e f f i c i e n c i e s
o b ta in e d w ere i n th e neighborhood o f 70 p e r c e n t^ and from th e s e
d a ta th e p o s s i b i l i t y o f an e l e c t r o l y t i c p ro c e s s t h a t co u ld be o p e ra te d a t t h a t e f f i c i e n c y i s c o n c e iv a b le w ith th e u se o f an A.G .R. anode«
Of c o u rs e , th e ad v an tag es to be r e a l i z e d w ith a s o lu tio n to th e anodic
problem w hereby g r e a t e r c u r r e n t d e n s i t i e s may be u t i l i z e d w ith o u t harm,
to th e anodes i s o b v io u so
The p ro d u c t as f a r as t e s t e d i s s u p e r io r to th e n a t u r a l manganese
d io x id e from th e A fric a n Gold C o a st, and th e f l e x i b i l i t y o f th e e le c ­
t r i c a l lo a d i s conducive to low power rates®
A nd-in c o n c lu s io n , i t i s th e r e f o r e l o g i c a l t h a t th e p ro d u c tio n o f
"
b a t t e r y a c ti v e manganese d io x id e i n a e l e c t r o l y t i c p ro c e ss from Mon­
ta n a o re s i s com m ercially f e a s i b l e as to t h e q u a lity o f th e p ro d u c t
and th e p o s s i b i l i t y o f o b ta in in g low power rates®
-
— 38 —
V.
(1 )
LITERATURE CITED
N ic h o ls, George W.,- " E l e c t r o l y t i c Manganese D io x id e", T ran sac­
tions o f th e E le c tro c h e m ic a l S o c ie ty , V ol. I X II, 1932, 392-l|038
(2)
Marx, P e t e r , t r a n s l a t e d by R a ls to n , O0 C0, "Anodic D e p o sitio n
o f Manganese D io x id e ", U n ited S ta te s D epartm ent o f th e I n t e r i o r *
B ureau o f Mines In fo rm a tio n C ir c u la r No0 I k ^ h3 May, I 9I4.8
(3 )
K is s e n , G0H0, " E l e c t r o l y t i c S y n th e s is o f B a tte r y A c tiv e Manganese
D io x id e ", F in a l R e p o rt, P r o j e c t No0 1 0 7 -7 , J u ly 31, 19h9*
(U)
S to r e y , O0 ¥ . , S te in h o f f , E r n e s t, and H o ff, E. R0, "The Anode
Problem i n th e E le c tr o d e p o s itio n o f Manganese D io x id e " , T ran s, a c tio n s o f th e -E le c tro c h e m ic a l S o c ie ty , Volume 86, 19UU, 33 7 -3 U^*
(5 ) Van A rs d a le , GeD. apd M aier, G0G0, "The E l e c t r o l y t i c B eh av io r o f
Manganese i n S u lp h a te S o lu tio n s " , T ra n s a c tio n s o f th e American
E le c tro c h e m ic a l S o c ie ty , Volume XXXIII, 1918, 109-131.
( 6 ) "O peration- o f E l e c t r o l y t i c Manganese P i l o t P la n t, " U n ite d S ta te s
D epartm ent o f I n t e r i o r , Bureau o f M ines B u l le tin Noe U6 3 , B oulder
C ity , Nevada, 19U6»
■VI A P P E N D I X
Table I ,
E le c t r o ly t ic MnOg Data
#
mi - s c a)
Q
!-af -H lO . O
Sn E-I M m
tH W h i s . H O -I
B o H g-
r o
Carbon I
Hard Carbon
ChemicalILd&d
' i o h. e
3 ,5 3 "
2 C^.lls
Carbon 2
D is c o h t.
h fte r
5 h rs.
Carbon 3
I C e ll
Hard Carbon
Chemical Lead
Carbon 4
I C e ll
Hard Carbon
Chemical Lead
Carbon 5
I C e ll
Hard Carbon
Chemical Lead
iC e ll I
Hard Carbon
Chemical Lead
Carbon 6
C e ll 2
Hard Carbon
Chemical Lead
77
137.-5
Table I 6 E le c t r o ly t ic MhOg Data (continued)
>—
>
g
RUM AND
CELL
I " .
Il
Carbon 6
C e ll 3
I Carbon 6 I
C e ll k ;
I Carbon 7
I Ay0 .,of
5 C e lls
I
I
S
:
Is
h|i
7
Hard Carbon _
uHemical Lead
7 •
S oft C arbon(2 )
Chemidal Lead
17.5
,
■ BC--K
I
CNiig
I s
Hard Carbon
Chemical Lead
_
„
.
Ill
III'
m '
•
■
10.3
8 .3
32
,
7 ,.!
/ — »
-
i
5
I l ■ IS III
S B
BJ
■ 1 1
8 .2 6
3 .0 $
60
■ .
137V5
67I
32
11.5
9 .3
7 .1
L .7.15
2 .9 5
41
6?
8 6 .2
10
50
6 .0 6
1 .9 2
1.P7
93
I
137.5
.67
.
:
:
d438 S o ft Carbon
Chemical Lead
C arbon.8.
C e ll 6'
Carbon 8
C e ll 7
1.75. S o ft Carbon.
Chemical .Lead
61.9
18
' 70.3
-
:
Carbon 9 I
C e ll I
(3 )
I Carbon 9 I
C e ll 2
I Carbon 9
6
I C e ll
18
I
S o ft Carbon
Chemical Lead
;
52
5 8 .8
'
io .i
-4.1-
1 .7 1
1 0 .1
4..1
1 .9 2
3 0 .8
39
S o ft Carbon ..
Chemical Lead
5.
. 1 7 .1
1 8 .4
S o ft Carbon
Chemical Lead
■5
54
50 ,1
93 . 137 <
67
.898
93
■
.
28.7
•
.90$
. -I
-
5
.
.
137.5
'6 7
■
11 .5
2V$6
-2.33
93
137.5 "
67
3 0 .4
1 1 .5
2 .6
3 .9 8
93
127.^5.
67
1 8 .6
11.5
2 .1
1.094
93. 1 3 M
•67
.
-
■
.
•
Table I ,
E le c t r o ly t ic MnOg Data (continued)
p k
E-I M (I) M
P "H
HH
I Carbon" 10
C e ll I
I
Carbon 10|
C e ll 2
I
I' P &
I ■ S o ft Carbon
Chemical Lead
I
I S o ft Carbon
I Chemical Lee
Carbon IOi I
C e ll 6
'
(4 ) .
Carbon 11
Soft.. Carbon
ChemibMl Lead
Carbon 12
I C e ll
S o ft Carbon
Chemical Lead
Carbon 13
C e ll I
Chemical Lead
Carbon 13
C e ll 2
I
Carbon 13
C e ll 3
|C arbon 14
C e ll I
O k %-E4
S o ft Carbon. :
Chemical Lead
S o ft Carbon
Chemical Lead
.
S o ft Carbon
(Chemical Lead
12
137; 5
T able I ,
El e c t r o l y b i c 'MnO^ D ata (continued).
Cti
ES 9 .S
o
% E-t- «5
H.f* «J|
wvL40 H—«
Carbon
C e ll 2
. Soft. Carbon
T Chemical Lead
Carbon 14
C e ll 3
S o ft Carbon
Chemical Lead
Carbon 15
C e ll I
S o ft Carbon
Chemical Lead
Carbon
C e ll 2
rSoft. Carbon
Chemical Lead
Carbon 15
C e ll 3
S o ft Carbon .
^heniical >Lead
Carbon 16
I C e ll
Chemical Lead
Carbon 17
I C e ll .
S o f t Carbon:
Chem ical Lead
Carbon 18
C e ll I
Carbon 18
I C e ll 2
125
.982 ( 93
S o f t . Carbon
Chemical Lead;'
'
Table I..
E le c t r o ly t ic MnOg Data (continued)
. -Q
ti -SQ S
O
^ ,2 ,6
...
A- '
H. b b !.COQ
Il H (D
g O
(7)
Carbon 18
I C e ll 3 .
I
I Carbon 18
S o ft Carbnn •
•ChemicSl Lead
C e l l -4
S o ft. Carbon
Chemical Lead
Carbon 19
I C e ll
C oft ,Carbon,.
.Chemical Lead
Carbon 20
C e ll 2 .
Carbon 21
!C e ll
•I
!'S o f t .Carbon..
Chem ical Lead.
I
s d f t Carbon
C hem icil Lead
S o f t . Carbon •
Chemical Lead
855 93
T able I ( c o n tin u e d ) ■
NOTES ■
Vr Run Carbon Ii and ru n Carbon 5 a re in a c c u r a te due to th e f a c t t h a t
d e t e r i o r a t i o n o f th e anodes caused c o n s id e ra b le carbon to be su s­
pended i n th e e l e c t r o l y t e w hich c o u ld n o t be e a s i l y s e p a ra te d from
t h e .manganese d io x id e o
(1 )
Carbon ro d s 7 /8 in c h e s i n d ia m e te r w ith i n s c r i p t i o n ltEtlO P la n ia
EFFEKT."
(2)
N a tio n a l C arbon Company anodes, A.G.R. ty p e g r a p h ite , a re l / 2
in c h th ic k and It in c h e s W ide0
(3)
Made a r e - r u n on t h i s p o in t (C arbon 16 ) .
(U)
Due to th e f a c t t h a t MnSO^ c o n c e n tra te s w ere n o t c o n s i s t e n t , th e
d a ta o f t h i s ru n a re n o t r e l i a b l e .
(5 )
S o lu tio n p re p a re d from r o a s te d p y r o l u s i t e . .
(6 )
Anode p l a t e d on one s id e o n ly .
(7 )
P o s s ib le e r r o r i n w e ig h ts .
— 1^6 —
T able I I .
CARBON AW
CELL '
A n a ly sis o f E l e c t r o l y t i c MnOg
STRUCTURE AVAILABLE Og AS
PER CENT OF MnOg
% Mn.
% Fe.
%Pb.
RATING
Carbon I
C e ll I
Samma
70.6
U8.3
I.U
0.15
Carbon 7
A ll C e lls
Gamma
75.6
5U.6
2.5
0 .13
2
Carbon 9
C e ll I
Gamma
0 .1 1
6
Carbon 9
C e ll 2
Gamma
65.0
5o.o
1 .9
0.13
3
Carbon 9
C e ll. 6
Gamma /
53.0
39.8
IoU
O o ll
5
Carbon 10
C e ll I
Gamma
111.7
3U.8
.1.8
0.08
7
Carbon 10
C e ll 2
Gamma
■ 6 U .ii
U7.2
0.17
U
Carbon 12
I C e ll
Gamma
82.p
3 7 .8
.
5U.7
1.2
_
I
.
•= 1*7 =■
T able I I I *
SAMPLE
Carbon
7
Carbon
7
Carbon
22
DISCHARGE.
RESISTANCE'
(ohms)
16 .2 /3 '
166 2 /3
B a tte ry T e s t B ata
TYPE OF ■ TEST END
DISCHARGE
VOLTAGE
C pntinuous
1 .0
C ontinuous
1.1 3
AVERAGE ■' INITIAL
INITIAL
CAPACITY
SERVICE- REQUIREMENTS
(h o u rs)
(b p ecso )
109*1;
130
o:
-4T
F igure 2 - The R e la tio n o f Current E f f ic i e n c y , Energy Requirem ents and C e ll V oltage
t o V arious Current D e n s it ie s .
CELL
PER
VOLTAGE
AVERAGE
PER
C EN T
KILOWATT-HOURS
CURRENT
PER
POUND
E F F IC IE N C Y
MnO,
o
EFFICIENCY
Ui
O
CURRENT
CC
Li
CL
Ui
IO
CENT
>
LU
O
<
PER
CC
LU
>
<
F igu re 3 - The R e la tio n o f Current E f f i c i e n c y , Energy Kequirements and C e ll V oltage
t o V arious E le c t r o ly t e A cid C o n cen tra tio n s.
iU
to
ANODE
- A .6 .R . GRAPHITE
CATHODE - CHEMICALLEAD
^*2^4
~ 6 7 g m /l
CURRENT DENSITY-,Ocrnp,^
ELECTRODE SPACING-1 in. ’
EFFICIENCIES__ !
MnO,
PER
--K ILO W A TT- HOURS PER POUND
150
GRAMS
Mn SO.
175
PER
L IT E R
F igu re 4 - The H e la tio n o f Current E f f ic i e n c y and Energy Hequirememts to V arious
Manganese S u lp h ate C o n cen tra tio n s.
LOWATT- HOURS
CENT
CURRENT
PER
EFFI
CURRENT
POUND
T E M P E R A T U R E -936 C- 3 eC
Figure 5 - The R e la tio n o f Current E f f i c i e n c y , Energy R equirem ents and. C e ll V oltage
to E le ctro d e S p acin g.
PER
VOLTAGE
KILOWATT - HOURS
CND
AVERAGE
C Jl
s—
CELL
Mn 0
ROUND
PER
CO
M
O
NTANASTATEUNIVERSITYLIBRARIES
762
0005201 6
■ r5 6 e
95124
S y lv a in . E . F .
The e l e c t r o l y t i c s y n th e s is o f
b a t t e r y a c ti v e manganese d io x id e .
DATE
l\t ISSUED TO
H9V 6 '62
^
S
y a -e P
^
MAR2?
95124
W&
N. >'
3 7 g
j> „
V y a bx
C *f. Z