Improvements in Electrolytic Apparatus for Decomposing Metallic Salts.
Year: 1894

page_text: PROVISIONAL SPECIFICATION.
Improvements in Electrolytic Apparatus for Decomposing Metallic
Salts.
I, CARL KELLNER, of IX Wasagasse No. 29, Vienna, Austria, and Cellulose Works,
Hallein, Austria, Director of the Kellner-Partington Paper-Pulp Co. Ltd and Doctor
of Philosophy, do hereby declare the nature of this invention to be as follows :—
This invention has reference to an apparatus for the electrolysis of alkaline salts
with the aid of a stationary mercury cathode, in which the amalgam formed by
electrolytic action has its location changed from the decomposing chamber in which
it is produced, to a combining chamber in which it is decomposed and the cation
combined with water, an acid, or other body, by the shifting of a partition which is
adapted to be moved to and fro in the mercury and serves to separate the two afore-
said chambers from each other. This partition is in this case made in the form of a
bell closed at its lower edge by a mercury seal and enclosing the decomposing
chamber, so that the amalgam formed in the latter is caused by the shifting of the
bell to have its location alternately on one side and on the other side of the bell with-
out itself changing or moving its position, and thus is caused to gain access to and
become situated in the combining chamber, whilst the mercury on the other side of
the partition, which was previously situated in the combining chamber, effects the
amalgamation of the metal that is being separated by the electrolytic decomposition
of the electrolyte.
In this way, a considerable output can be obtained from the apparatus with a
comparatively small quantity of mercury, because both operations can take place
simultaneously and uninterruptedly.
In the accompanying drawings,
Fig. 1 is a vertical section taken through one cell of an apparatus constructed
according to this invention;
Fig. 2 is a longitudinal section, to a smaller scale, taken through the whole
apparatus;
Fig. 3 is a horizontal section on the line y-y of Fig. 2; and
Figs. 4 and 5 are sections through the bell showing two forms of construction of
the latter.
The apparatus shown comprises a vessel A for the reception of the electrolyte to be
decomposed, and a trough B inserted or suspended in the vessel A, this trough having
in its bottom openings b which are surrounded by projecting borders that serve to
prevent the escape, through the openings b, of the mercury layer or cathode C which
serves as a cathode and covers the bottom of the trough. The anodes D are arranged
in the electrolytic space of the vessel A, horizontally or vertically, and in the latter
case may as shown also project through the openings into the trough B. Each
of the trough openings is covered over by a bell E of non-conducting material,

page_text: such for example as glass, stoneware, porcelain, or. ebonite, which dips at its lower
free edge into the mercury and is of greater width than the opening b, so that it can
be moved to and fro through a certain distance over this opening, the extent of this
movement being limited by the upwardly projecting border b¹. The bell thus encloses
the decomposing chamber communicating with the vessel A, and forms an electrically
non-conducting partition between the decomposing chamber and the combining
chamber of the trough B which is charged above the mercury cathode C, which
constitutes the seal, with water, acid or other substance with which it is desired to
cause the cation, previously taken up by the mercury cathode, to combine.
In order that the mercury shall not become displaced by the lower end of the bell
sliding over the bottom of the trough B when the bell is being moved, slots or
notches e or b² are provided in the lower edge of the bell, as in Figs. 1 and 4, or in
the bottom of the trough, as in Fig. 5.
A gas exit pipe F leads from the decomposing chamber to the exterior of the
vessel A.
The anode D and the mercury cathode C are suitably connected to the terminals
of a suitable source of electricity.
In an apparatus of large size, such as is intended to be employed on an industrial
scale, the whole of the bells E are preferably united to form a cover which is pro-
vided with partitions and is adapted to be moved to and fro in the trough B, the
spaces E' between every two bells being arranged to communicate by means of lateral
openings with the trough B, as shown in Fig. 2. The gas exit pipes F are then
arranged in such a manner that the generated gas is led through all the bells in
succession and is drawn off from the last bell.
The manner of working the apparatus is as follows:-
The electrolyte, for instance a solution of common salt, within the vessel A and
the decomposing spaces or chambers, becomes decomposed by the electrolytic action
which takes place under the bells E, the liberated chlorine gas being led off through
the pipe F, whilst the metallic sodium forms an amalgam with the mercury cathode C
which is situated within the bells E on one side of the anodes D, viz. on the right
hand side in Fig. 1. If now the bells be shifted to the left hand into the position
shown in dotted lines in Fig. 1, the stationary mercury cathode together with the
amalgam becomes thereby situated in the combining chamber of the trough B which
is charged, it may be for instance with water. The sodium separates out from the
amalgam and combines with the water to form sodic hydrate. At the same time, by
the shifting of the bells, that portion of the mercury which was previously situated
outside the left hand side portions of the bells, that is to say in the combining
chamber, will now be located in the decomposing chamber, and acts as the cathode
to produce the amalgamation of the sodium which is continually being separated in
the said decomposing chamber. If the bells after a suitable interval of time, be
shifted back into the position shown in full lines, i.e. to the right hand, the mercury
on the left hand side of the anodes, together with the amalgam formed thereon,
becomes situated in the combining chamber of the trough, and consequently within
the sphere of action of the water in such chamber, whilst on the other hand the
mercury situated on the right hand side of the anodes, and the amalgam portion of
which has been dissolved in the meantime, becomes again situated in the decom-
posing chamber for the purpose of forming fresh amalgam. It will thus be seen that
by the to and fro movement of the bells, the transposition of the amalgam formed
in the decomposing chambers to the combining chambers, and the practically con-
tinuous formation of caustic-soda in the latter, are caused to take place alternately on
the one side and on the other side of the anodes, whilst the mercury cathode itself
remains at rest.

page_text: Improvements in Electrolytic Apparatus for Decomposing Metallic
Salts.
I, CARL KELLNER, of IX Wasagasse No. 29, Vienna, Austria, and Cellulose Works,
Hallein, Austria, Director of the Kellner-Partington Paper-Pulp Coy. Ltd. and
Doctor of Philosophy, do hereby declare the nature of this invention and in what
manner the same is to be performed to be particularly described and ascertained in
and by the following statement :-
This invention has reference to an apparatus for the electrolysis of alkaline salts
with the aid of a stationary mercury cathode, in which the amalgam formed by
electrolytic action, has its location changed from the decomposing chainber, in which
it is produced, to a combining chamber, in which it is decomposed and the cation
combined with water, an acid, or other body, by the shifting of a partition which is
adapted to be moved to and fro in the mercury and serves to separate the two
aforesaid chambers from each other. The partition is in this case made in the form
of a bell closed at its lower edge by a mercury seal and enclosing the decomposing
chamber, so that the amalgam formed in the latter is caused by the shifting of the
bell to have its location alternately on one side and on the other side of the bell
without itself changing or moving its position, and is thus caused to gain access to and
become situated in the combining chamber, whilst the mercury on the other side of
the partition, which was previously situated in the combining chamber, effects in the
decomposing chamber the amalgamation of the metal that is being separated by the
electrolytic decoin position of the electrolyte. In this way, a considerable-output
enn--be--obtained from-the apparatus with a comparatively-small-quantity of
mercury, because--both operations--ean take--place--simultaneously and uninter-
ruptedly.
In the drawings filed with my Provisional Specification,
Fig. 1 is a vertical section taken through one cell of an apparatus constructed
according to this invention;
Fig. 2 is a longitudinal section, to a smaller scale, taken through the whole
apparatus;
Fig. 3 is a horizontal section on the line y-y of Fig. 2; and
Figs. 4 and 5 are sections through the bell showing two different forms of
construction of the latter.
In the accompanying drawings,
Fig. 6 is a longitudinal vertical section illustrating a modified construction of the
apparatus shown in Fig. 2.
Fig. 7 is a vertical section, and Fig. 8 a horizontal section, taken in different
planes, showing a further modified construction of the said apparatus.
Fig. 9 is a vertical section through a cell of the apparatus, similar to that shown in
Fig. 1, but provided with a short circuited secondary electrode for the purpose of
rapidly removing the alkaline metal from the amalgam that has been formed.
The apparatus shown in Figs. 1, 2 and 3 comprises a vessel A for the reception of
the electrolyte to be decomposed, and a trough B inserted or suspended in the vessel A,
this trough having in its bottom openings 6 which are surrounded by projecting
borders b¹ that serve to prevent the escape, through the said openings, of the layer
of mercury C which serves as a cathode and covers the bottom of the trough. The
anodes D are arranged in the electrolytic space of the vessel A, horizontally or
vertically, and in the latter case may, as shown, also project through the openings b
into the trough B. Each of the trough openings is covered over by a bell E of non-
conducting material, such for example, as glass, stoneware, porcelain, or ebonite,
which dips at its lower free edge into the mercury and is of greater width than the

page_text: opening b, so that it can be moved to and fro through a certain distance over this
opening, the extent of this movement being limited by the upwardly projecting
border 6. The bell thus encloses the decomposing chamber communicating with
the vessel A, and forms an electrically non-conducting partition between the
decomposing chamber and the combining chamber of the trough B which is charged
above the mercury cathode C, which constitutes the seal, with water, acid or other
substance with which it is desired to cause the cation, previously taken up by the
mercury cathode, to combine.
In order that the mercury shall not become displaced by the lower end of the bell E
sliding over the bottom of the trough B when the bell is being moved, slots or
notches or 62 are provided respectively in the lower edge of the bell, (as in Figs. 1
and 4), or in the bottom of the, trough, as in Fig. 5. A gas exit pipe F leads from
the decomposing chamber to the exterior of the vessel A.
The anode D and the mercury cathode C are connected to the terminals of a suitable
source of electricity.
In an apparatus of large size, such as is intended to be employed on an industrial
scale, the whole of the bells E are preferably united to form a cover which is provided
with partitions and is adapted to be moved to and fro in the trough B, the spaces E¹
between every two bells being arranged to communicate by means of lateral openings
with the trough B, as shown in Fig. 2. The gas exit pipes F are then arranged in
such a manner that the generated gas is led through all the bells in succession and
is drawn off from the last bell.
The manner of working the apparatus is as follows:-
The electrolyte, for instance a solution of common salt, within the vessel A and the
decomposing spaces or chambers, becomes decomposed by the electrolytic action which
takes place under the bells E, the liberated chlorine gas being led off through the
pipe F, whilst the metallic sodium forms an amalgam with the mercury cathode C
which is situated within the bells E on one side of the anodes D, viz. on the right
hand side in Fig. 1. If now the bells be shifted to the left, into the position shown in
dotted lines in Fig. 1, the stationary mercury cathode together with the amalgamı
becomes thereby situated in the combining chamber of the trough B which is charged,
it may be for instance with water. The sodium separates out from the amalgam and
combines with the water to form sodic hydrate. At the same time, by the shifting of
the bells, that portion of the mercury which was previously situated outside the left
hand side portions of the bells, that is to say, in the combining chamber, will now be
located in the decomposing chamber, and acts as the cathode to again produce an
amalgam with the sodium which is continually being separated in the said decomposing
chamber. If the bells, after a suitable interval of time, be shifted back into the
position shown in full lines i.e. to the right hand, the mercury on the left hand side
of the anodes, together with the amalgam formed thereon, again becomes situated, in
the combining chamber of the trough, and consequently within the sphere of action
of the water in such chamber, whilst on the other hand the mercury situated on the
right hand side of the anodes, and the amalgam portion of which has been acted upon
in the meantime by water to remove the sodium therefrom, becomes again situated
in the decomposing chambers for the purpose of forming fresh amalgam. It will
thus be seen that by the to and fro movement of the bells, the transposition of the
amalgam formed in the decomposing chambers to the combining chamber, and the
practically continuous formation of caustic soda in the latter, are caused to take place
alternately on the one side and on the other side of the anodes, whilst the mercury
cathode itself remains at rest.
It is obvious that the arrangement of apparatus herein before described can be
modified by causing the generation of chlorine to take place outside, and the decom-
position of the amalgam to take place inside the bells E. In this case, the decomposing
and forming chambers are merely interchanged. Fig. 6 illustrates a construction
of apparatus of this kind, in which the vessel A contains the mercury cathode C and
the solution of cominon salt to be decomposed, whilst the bells E that dip into the
mercury, are charged with water with which the sodium that becomes separated from

page_text: the amalgam on the shifting of the bells, combines to form sodic hydrate. The
vessel A is provided with a cover A¹ that is adapted to close gas-tight, and from which
leads a pipe F that serves to carry off the chlorine gas generated in the said vessel. The
cover is provided at a suitable place with an opening which is closed by means of a
movable cover A' that preferably dips into a sealing liquid for the purpose of making
a.gas-tight joint at this part. Through the cover A2 there passes a pipe H which
Berves for discharging the hydrogen that forms in the bells E and is supplied to
the pipe H by connecting pipes H. The bells are rigidly connected together,
and, as in the previous case, are so arranged that they can be moved to-and-fro
in the vessel A, this movement being shared by the pipe H and the sliding
cover A²
The positive terminal wire leading to the source of electricity, is electrically
connected by a conductor that is inserted in a tight manner in a glass tube I
capable of movement in a stuffing-box in the wall of the vessel to the upper part
of each of the bells E, such upper part being made of electrically conducting.
material whilst the lower part of each bell, which dips in the mercury, is either
nade of, or covered with a non-conducting material, the upper part of the bell
thus constitutes the anode. The negative terminal wire is connected to the
mercury.
Instead of being slidden along rectilinearly, the bell E, or the vessel A, or the
bottom of the latter, may have a rotary motion imparted to it. An arrangement of
apparatus of this kind is shown in Figs. 7 and 8.
Here the vessel A, which contains the mercury cathode C, is constructed in the
form of a disc provided with an upwardly projecting edge and the hub of which is
fixed on a vertical shaft K that is rotated by suitable means. The decomposing and
combining chambers are formed by means of fixed radially arranged bells E which
are connected together so as to form a cover provided with partitions, as in the
arrangement shown in Fig. 1.
The decomposing and combining chambers follow each other in succession and are
respectively provided with the chlorine discharge pipe F, and with pipes H for dis-
charging the hydrogen.
A number of such disc-shaped vessels A with radially arranged bells E may be
mounted one above the other upon one and the same shaft. Also the disc shaped
vessels A may be fixed, and the bells E be mounted on the shaft K so as to rotate
therewith, which is equivalent to the mere reversal of the apparatus described with
reference to Figs. 7 and 8, and requires no further description. The manner of
operation is the same as before described, in all cases.
If it be desired that the alkaline metal shall be rapidly removed from the amalgam
formed, then in the case of apparatus of the kind herein described, there may be
employed the method specified in Claim 7 of the specification of my British Patent
No. 17169 of A.D. 1892, whereby the heat liberated in the formation of amalgam is
converted into electrical energy.
For this purpose, into the trough B of the apparatus (Fig. 9) or into the bells E
(Fig. 6), or into the combining cells of the bells E (Fig. 7), that is to say, always in
the chamber in which the separation of the sodium is to take place, there is suspended
a third electrode G which is electrically connected, in any suitable way, to one of the
terminal wires, viz. that extending from the mercury cathode (Figs 6 and 9, thereby
forming a short-circuited secondary element composed of the mercury cathode C and
the electrode G, which element effects the rapid separation or removal of the alkaline
metal from the amalgam. Each third electrode G may be carried either by the corre-
sponding bell E, or by the bottom of the vessel A, through any suitable connection
which should be of non-conducting material, or be covered with such material.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is
1. An apparatus for the electrolysis of metallic salts with the aid of a stationary

page_text: mercury cathode, in which partitions or bells capable of being moved to and fro, and
dipping into the said mercury cathode, are arranged to separate the decomposing and
combining spaces or chambers, from each other and by their to and fro movement, to
cause the mercury cathode to be located alternately within the sphere of action of the
electrolyte and of the substance to be combined with the cation produced, substantially
as herein before described with reference to and illustrated by Figs. 1 and 2 of the
drawings referred to.
2. The modification of the apparatus specified in the preceding claim, in which the
movable partitions or bells are provided with pipes H¹ for carrying off hydrogen, and
are arranged in a closed vessel A which contains the mercury cathode and is provided
with a pipe F for carrying off chlorine, substantially as herein before described with
reference to and illustrated by Fig. 6 of the accompanying drawings.
3. The modification of the apparatus specified in Claim 1, in which-one-or--more
vessels-A-is-or-are-mounted-on-a-vertical shaft so as to be capable of rotating
relatively to the fixed-partitions or bells that dip into-the-mercury enthode carried
by-the-said-vessel-or-vessels, or in which the said partitions or bells are capable of
rotating in a fixed vessel or vessels, substantially as herein before described with
reference to and-illustrated-by Figs. 7 and 8 of the accompanying drawings.
4. In apparatus-of the-kind-specified-in-the-preceding claims, the-arrangement-of
e-third-electrode G-in-the combining chamber or in each such-chamber,-the-caid
electrode-G, or each of them when there are more-than-one, forming with--the
mercury-cathode-n chort circuited secondary element, for the purpose of rapidly
removing the--alkaline metal from-the-amalgam-substantially as hereinbefore
described with reference to und illustrated by Fig-0 of the accompanying
drawings.
4. In apparatus of the kind specified in the preceding claims, the arrangement
of slots or notches e or be in the edges of the partitions or bells, or in the bottom of
the vessel that contains the mercury cathode, for the purpose of obviating displace-
ment of the mercury when moving the partitions or bells relatively to the vessel,
substantially as herein before described with reference to and illustrated by Figs. 4
and 5 of the drawings herein referred to.