close

Вход

Забыли?

вход по аккаунту

?

Патент USA US2849403

код для вставки
Aug. 26, 1958
2,849,393
C DEPREZ ETAL
.CATHODIC DEVICE FOR ELECTROLYTIC CELLS HAVING
A MOVING MERCURY CATHODE
Filed Jan. 4, 1955
I 20
21
ice
1
Patented Aug. 26, 195%}
2
The principle of the cathodic device according to the
invention is, by way of example, diagrammatically il
lustrated in Figures 1 and 2 of the accompanying draw
2,849,393
CATHODIC DE‘VHIE FOR ELECTROLYTIC CELLS
HAVING A MQViNG MERCURY CATHUDE
ings.
Figure 1 shows a front view of a mercury supporting
plate provided with a means for the mercury feed,
Figure 2 is a vertical section of this support,
Charles Deprez and Jean Clement, Brusseis, Beigiuin,
assignors to Solvay & €ie., Brussels, Prelgium, a lieh
gian company
Application January 4, 1%5, Serial No. 47?,746
Claims priority, application Beigium ianuary 27, 1954
Figure 3 is a perspective of a cathode.
Referring to the drawings the support 1 is provided
iii with grooves 2 and 3 which are, according to this par
ticular example, perpendicular to one another.
On the
support 1 is ?xed a tank 4, said tank being provided
13 Claims. (Cl. 204-219)
with an over?ow 7 known per se, which tank receives a
supply of mercury 5 through a pipe 6.
The mercury coming from overflow 7 ?ows along the
The invention relates to a cathodic device for electro
lytic cells having a moving mercury cathode and more
particularly to the metallic surface forming the sup
port for the mercury in cells of the vertical type for the
support 1 in a very thin layer of about one-tenth of a
millimetre. its vertical fall is checked by the grooves 2,
electrolysis of salt solutions whose cations, discharged
at the cathode, are capable of forming ‘amalgams with __
the mercury.
The main di?iculty encountered with electrolytic cells
of the vertical type, for instance, is the obtaining of a
thin uniform and continuous mercury sheet which covers
3 which have a depth of about 0.3 mm. and a width of
about 1.5 mm. The channels or grooves, inclined in
opposite directions and forming a grid of about 4 mm.
squares, direct part of the mercury towards the external
edges of the support and thus contribute to maintain a
perfect continuity of the mercury sheet on the gofered
support.
completely the metallic supporting surface. In fact, the
By way of example, a supporting plate grooved asv de
mercury sheet has a marked tendency to tear or to as
scribed above has been fed with mercury at a ?ow of l
litre/minute per metre of width of the support. The
semble in threads, thus leaving uncovered a more or less
large part of the supporting surface, thereby provoking
cathode thus formed, working in an electrolytic cell at
a cathode current density of 30 amp/sq. dm., has pro
detrimental secondary reactions in the course of the elec
trolysis.
30 duced an amalgam whose alkali metal concentration was
Up to now, no satisfactory solution has been found to "
0.5 percent by weight, the useful height of the cathode
overcome this di?iculty.
One known proposal relates to the use of a system
of steps provided in the supporting body, along which
the mercury ?ows in the form of successive cascades. ‘
A second known proposal seeks to counteract the tend
ency for the liquid metal sheet to separate, by causing
it to flow on a support provided with vertical grooves,
the individual grooves being very closely spaced.
A third known proposal for overcoming the above
40 set may be no longer parallel to one another.
mentioned dit?culty relates to the use of a smooth ver
tical support whose vertical edges approach each other
towards its lower portion.
Application of either of the ?rst or second proposals
leads to a reduction in the occurrence of secondary re- -=
actions without eliminating them completely.
Application of the third proposal requires a very con
siderable mercury feed. Moreover in this latter case the
speed with which the mercury sheet falls is considerable
and provokes a strong whirling in the electrolyte. In "»
the particular case of the electrolysis of aqueous solu
tions of alkali metal chlorides, this phenomenon is ac
companied by an appreciable loss in yield due to the
recombination ‘of the chlorine dissolved in the electro
lyte with the ‘amalgamated alkali metal. On account of i
the high mercury feed the alkali metal concentration is
normally low and in order to obtain concentrations suit~
able in practice, it is necessary to provide supports of
great length, so that such electrolytic cells would have
to be of excessive height.
60
It is an object of the present invention to overcome
being about 2 metres.
The effect of checking of the fall of and spreading
of the mercury caused by the grooves is dependent mainly
on the viscosity and the surface tension of the amalgam
which ?ows‘ on the metallic support. These factors con
tinue to increase continually along the flow of mercury.
In order to take into account these variations, accord
ing to another aspect of the invention the grooves of one
The angles
which they form with the horizontal become greater and
greater the closer they approach the lower part of the
support. However, an angle of 45° seems to be the
maximal limit.
The supporting surfaces can be plane or curved as de
sired. In the case of a vertical cell the support can be
of tubular form and each of the two sets of grooves con
stitute one or more helices in the manner of a multiple
thread screw, the said helices can be of uniform pitch
or, in the case when it is desired to take into account
the variation of the viscosity and/or of the surface ten
sion of the amalgam, the pitch can be variable and in
crease towards the lower part of the support.
The supporting surfaces can be formed of platesv hav
ing grooves on one or two faces, which plates can be
provided internally with an arrangement for the circu
lation of a heating or cooling ?uid, in order to regulate
the temperature, of the cathode.
Figure 3 of the accompanying drawings illustrates by
way of example a cathode constituted by a ?at hollow
body ‘of iron grooved on both faces. The said cathode
the disadvantages inherent in the known proposals by
comprises two opposite surfaces 8, provided with grooves,
means of a device which allows a considerable slowing
and whose horizontal upper edges 9 form overflows‘ 1E3
fed with mercury from two cavities 11 separated by a
partition 12. The mercury is fed into the cavities through
tubes 13, over?ows at 10, ?ows along the grooved sur
down of the mercury ?ow whilst maintaining the metal
spread on the supporting surface and by covering the
latter completely with a thin sheet.
According to one aspect the invention is characterised
in that the metal support of the mercury is provided with
two sets of grooves, inclined in opposite directions and
intersecting in such a manner that their intersection de
termines angles the bisectors of which extend horizon
tally.
faces 8, and the amalgam produced during the electroly
sis enters a collector 14 from where it leaves the elec
trolytic cell through a tube 15. The cathode is connected
with the source of electric current by current supply
means to. Circulation of the heating or refrigerating
fluid takes place through tubes 17 and iii.
2,849,393
it
7. An electrolytic cell as de?ned in claim 6 in which
.
The metallic surfaces which are not covered by mer
cuiy should not be brought into .contact with the electro
lyte; for this reason they are covered by a protective in
sulating coating. As an insulation there can be used an
adhering Coating applied to the partition 12, the current
supply means 16, the mercury feeding tubes 13, and the
collector 14. For constructional reasons, the lateral
faces 19 of the cathode assembly may be covered by an
insulating elastic sheet 20 forming a joint and secured
to the body by terminal plates 21 of metal protected by an
k.
the support includes a cylindrical portion on which said
grooves are provided.
8. An electrolytic cell as de?ned in claim 7 in which
the axis of the cylindrical portion extends in a direction
perpendicular to that of the cell.
9. In an electrolytic cell of the vertical type including
a moving mercury cathode, a vertical support surface
for the mercury, said surface comprising a monoplanar
surface area for receiving the mercury cathode stream in
insulating layer, the plates being kept in position by nuts
terrupted by two sets of intersecting grooves extending
22 and washers 24 screwed on rods 23.
inwardly in a direction away from the exposed surface of
said mercury cathode stream, corresponding grooves in
the two sets being inclined at substantially equal but op
posite angles to the horizontal, the grooves of each of
In the same
way, tubes 17 and 18 passing through the joint 20 and
plates 21 are provided with screw nuts 25 and washers
26. After the assembly, the non-protected metal ends
which protrude from the plates 21 are likewise covered
with an insulating coating.
We claim:
1. In an electrolytic cell including a moving mercury
cathode, a support surface for the mercury, said support
surface comprising a monoplanar surface area for re
ceiving the mercury cathode stream interrupted by two
sets of grooves extending inwardly in a direction away
the respective sets forming increasing angles with the
horizontal towards the lower portion of said surface.
10. A support surface for a mercury stream for use
an electrolytic cell of the vertical type including a mov
ing mercury cathode, said surface being the surface of a
body provided with means for controlling the tempera
ture of said cathodeand being composed of an electrically
conductive-material and comprising a monoplanar surface
area for receiving the mercury'cathodestream interrupted
from the exposed surface of said mercury cathode stream,
said two sets of- grooves being inclined’ in opposite direc 25 by two sets of intersecting grooves extending inwardly
in a direction away from the exposed surface of said
tions and intersecting in such a manner. that their inter
mercury cathode stream, corresponding grooves in the
sections de?ne angles the bisectors of which extend
two sets being inclined‘ at substantially equal but opposite
horizontally.
’
2. In an electrolytic cell including a moving mercury
angles to-the horizontal.
11. A support surface as de?ned‘ in claim 10, provided
cathode, a support surface for the mercury, said support 30
with means for circulating a ?uid within the body having
surface comprising a monoplanar surface area for re
said support surface as its outer surface, whereby the
ceiving the mercury cathode stream interrupted by two
temperature of the moving mercury cathode may be
sets of intersecting grooves extending inwardly in a direc
tion away from the exposed surface of said mercury
, adjusted.
12. A vertical support surface for a mercury stream
cathode stream, corresponding grooves in the two sets 35
for use in an electrolytic cell of the vertical type including
being inclined at substantially equal- but opposite angles
a moving mercury cathode‘, said ‘surface being-the surface
to the horizontal.
of a body provided with means for-controlling'its temper
3. In an electrolytic cell including a moving mercury
ature, said surface comprisingga-rnonoplanar surface area
cathode, a support surface for the mercury, said surface
being composed of an electrically conductive material and 40 for receiving the mercury cathode stream interrupted by
two sets of intersecting grooves‘ extending-inwardly in a
comprising a monoplanar surface area for receiving the
direction away from the exposed surface of said mercury
mercury cathode stream interrupted by two sets of inter
secting grooves extending inwardly in a direction away
cathode stream, corresponding grooves in the two sets
being inclined at substantially equal but opposite angles
from the exposedsurface‘of said mercury cathode stream,
corresponding grooves in the two- sets being inclined at
to the horizontal, the grooves of each of-the respective
substantially equal but opposite angles to the horizontal.
sets forming increasing angles with the horizontal towards
4. An electrolytic cell as de?ned in claim 3 in which
said monoplanar area is de?ned by a ?at surface of ‘the
the lower portion of said surface.
13. A support surface as de?ned ,in claim 12 provided
with means for circulating a ?uid withinthe body having
said support surface as its outer surface, whereby the
temperature of the moving mercury cathode may be
support.
5. An electrolytic cell as de?ned in claim 3 in which
said monoplanar area is de?ned by a curved surface of
said support.
6. In an electrolytic cell of the vertical type including
a moving mercury cathode, a vertical support surface
for the mercury, said surface being composed of an
electrically conductive material and comprising a mono
planar surface area for receiving the mercury cathode
stream interrupted by two sets of intersecting grooves ex
tending inwardly in‘ a direction away from the exposed
surface of said mercury cathode stream, corresponding 60
grooves in the two sets being inclined at substantially
equal but opposite angles to the horizontal.
adjusted.
References Cited in the ?le of this patent
UNITED STATES PATENTS
733,643
1,176,551
Gurwitsch ___________ __ July 14, 1903
Heinemann _________ __ Mar. 21, 1916
692,954
Germany ____________ .._. June 29, 1940
FOREIGN PATENTS
Документ
Категория
Без категории
Просмотров
0
Размер файла
393 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа