Method of and Apparatus for Effecting Electrolysis.
Year: 1894

page_text: Date of Application, 17th Dec., 1894
Complete Specification Left, 17th Oct., 1895-Accepted, 17th Dec., 1895
PROVISIONAL SPECIFICATION.
Method of and Apparatus for Effecting Electrolysis.
I, Dr. CARL KELLNER, of IX Wasagasse No. 29, Vienna, Austria, and
Cellulose Works, Hallein, Austria, Doctor of Philosophy and Director of the
Kellner-Partington Paper-pulp Company, Limited, do hereby declare the nature of
this invention to be as follows:-
-
As is well known, the vertical arrangement of electrolytic apparatus is for many
reasons to be preferred to the horizontal arrangement. This is especially the case
with apparatus in which mercury is employed as an electrode, because:-
1. It is difficult to place and maintain large and heavy apparatus horizontal
with such accuracy as to cause the bottom to be everywhere uniformly covered with
a thin layer of this expensive metal.
2. It is difficult to act electrically upon large horizontal surfaces uniformly, and
experience shows that an amalgam of an alkali metal decomposes the water of the
electrolyte at the places of small current density, which in the case of the
electrolysis of the chlorides of the alkali metals, causes the formation of
hypochlorites.
3. The output-capacity of horizontal apparatus is restricted by difficulties in
respect of construction and material, many contacts, large space, and numerous
apparatus being required.
4. The surface of the mercury, which alone is effective or operative, is rendered
impure by the anodes arranged above it.
5. In practical working, it is very inconvenient to keep large quantities of
mercury in constant uniform movement.
It has heretofore been proposed to employ mercury in a vertical or inclined form
as a cathode for instance, by causing it to trickle in thin sheets or streams down
over vertical or slightly inclined amalgamated metallic surfaces constituting the
cathode, or by drawing amalgamated metallic bodies, bands, and strips of sheet
metal, through mercury. But all these apparatus are so complicated, and their
output is so small, as to render them unfit for use for working on a large scale.
Now the present invention is designed to provide means for enabling the
complete decomposition of metallic chlorides to be effected electrolytically, with
the practically complete utilization of the electro-chemical equivalent of energy, by
means of vertically arranged extremely simple, durable and reliably working
apparatus without the use of a porous diaphragm or partition.
According to this invention, the mercury cathode is employed in the form of
narrow strips which are formed by a system of channels and are compelled to
circulate in a helical or zigzag path or paths about the anode or anodes, whilst
they are being continuously freed, in a cell separated from the decomposing
chamber, from the kation they have taken up in their course.
By employing this method it has also been rendered possible to construct
apparatus of any desired output capacity.
The quantity of mercury required is small in consequence of the high current'
density that is attainable therewith; and the raising apparatus or operation is
simple because it is sufficient, in tlie case of an apparatus however large, to raise upi

page_text: to the initial convolution of the helical path only that quantity of mercury which is
requisite for a single convolution of the helix.
In carrying this method into practice, the apparatus illustrated by way of
example in a number of modified forms in the accompanying drawings, may be
employed.
Fig. 1 illustrates in vertical section ;
Fig. 2 partly in plan and partly in horizontal section, an apparatus constructed
of cylindrical shape.
Figs. 3 & are respectively a perspective view, a part vertical section, and a
part horizontal section showing a cylinder provided with helical channels for
guiding the mercury strip or stream.
Figs. 6, 7 & 8 are respectively an elevation partly in section, a vertical section,
and a horizontal section, illustrating another construction of apparatus of flat
shape, adapted to be inserted into existing electrolytic apparatus, in place of a
diaphragm.
Figs. 9 & 10 show respectively in horizontal and vertical section, another
arrangement of apparatus in which the strip-like layer of mercury, in contra-
distinction to the two forms of apparatus shown in Figs. 1 to 8, is subjected to
action or influence on both sides (is "irradiated" from both sides), and is
consequently adapted to work with a large current density.
Fig. 11 shows partly in elevation and partly in section, a portion of the channel
used in the apparatus shown in Figs. 9 & 10.
such as
In the apparatus illustrated in Figs. 1-5, A is a cylinder composed of material
porcelain or stoneware provided with numerous helical channels a, a, all..
b, b¹¹.....
(of which only a few are shown for the sake of clearness) through
which the mercury flows in the form of a stream, the parts of the mercury stream
in the several channels constituting strips. The channels are arranged on the
cylinder A (Fig. 3) in such a manner that the first, third, fifth and so on
convolutions, that is to say, the channels forming the odd-numbered convolutions of
the helix, are situated on the inner surface of the cylinder, whilst the channels
forming the second, fourth, sixth and so on, or even-numbered convolutions, are
situated on the outer surface of the cylinder. The internal channels situated in
the decomposing cell communicate with the external channels situated in the
forming cell each by means of an opening or slit c formed in the wall of the
cylinder.
In the cylinder A. to the uppermost channel a of which the mercury is supplied
through a pipe 7, there is inserted a suitable anode (or anodes) B preferably of
cylindrical shape, which is filled with the solid salt to be decomposed, so that
this salt cannot enter into the mercury channels, but, by passing from below the
anode into the electrolyte around the same will become dissolved therein and so
maintain the strength thereof.
The whole is arranged in a vessel C which contains the substance (water or
other fluid reagent) with which the separated kation is to be combined, and is
closed by a cover d. is the inlet pipe for the liquid reagent, and and ² are
gas exit pipes.
The anode B is connected to the positive pole of an electric generator, and the
mercury is connected with the negative pole thereof.
As the resistance of the long stream of mercury, with the considerable current
consumption, would be very appreciable, it is advisable to connect the stream of
mercury at various points in its length with the negative pole of the electric
generator. For this purpose the vessel C is made of metal, for example iron, and
is connected electrically at various points with the mercury by means of the wires n,
the vessel itself being connected to a wire n', as shown on the left hand side of
Fig. 1, by which it is placed in electrical connection with the negative pole of the
electric generator.
But if electricity produced by the combination of the kation dissolved in the
mercury cathode, with the liquid reagent in the vessel C, is to be utilised, then, as

page_text: shown on the right hand side of Fig. 1. the wires are connected to form another
common return lead n² to the negative pole of the electric generator, another
lead m extending from the vessel C. The mercury in the external channels and
the vessel, form in this case the electrodes of a secondary element which can be
advantageously used for supplying current to another electrolyti apparatus, or for
relieving the main source of current supply.
If it is mainly desired to effect a decomposition of the mercury amalgun that
shall be capable of regulation, all the mercury strips are again connected by a lead
with the negative pole of the dynamo machine, and into this lead there is included
a resistance W, Fig. 9, and beyond the latter a connection is male with the
conducting vessel C. In this way there is formel a short-circuited element which
promotes the formation of caustic soda. The efficiency of this element, that is to
say, the speed of the decomposition of the amalgam, may be regulated by varying
the resistance.
The mode of operation of the apparatus is as follows:
Assuming for example that common salt is to be decomposed with the object of
producing simultaneously by electrolysis, caustic soda, ammonia, and chlorine gas,
then a solution of comm in salt is placed in the decomposing vessel A, and water in
the combining vessel C and mercury is poured into the topmost inner channel.
As soon as the electric circuit is completel, sodium will be separated from the
solution of common salt contained in the decomposing vessel and will unit with the
mercury kathode, but during the passage of the mercury amalgam through
the secon helical convolution & situated on the outside of the vessel A, the above
mentioned sodium will combine with the water in the combining vessel, with
formation of caustic sola and liberation of hydrogen. The mercury freel fron the
sodium then passes at once into the next inner helical convolution a', again
amalgamates with sodium, carries the same into the outer helical convolution in
the combining vessel where it yields ap the sodium as before, and so on passing
finally out of the apparatus in a pure condition by a pipe q' to a pump por
other suitable raising device by which it is again delivered to the pipe and thus to
the topmost inner channel a for re-use.
The concentrated solution of caustic soda is drawn off from the vessel C through
a pipe p. If instead of water, a solution of sodium nitrate be used in the combining
vessel, ammonia gas will be liberated instead of hydrogen. The hydrogen or
ammonia, as the case may be, escapes through the pipe, whilst the chlorine
escapes through the pipe, the gases being conducted by these pipes to the place
where they are to be utilized.
The hereinbefore described arrangement of vessel A with mercury channels
serves to provide a fluid tight division between the interiors of the decomposing
and combining vessels.
But in cases where no value will be attached to this arrangement, there may be
employed in place of the cylinder A, an insulating wall for separating the two
spaces, as shown in Figs. 6 7 and 8. This wall is provided on both sides with
the oppositely inclined channels a, a¹ ..that are connectel together by means
of slots r, so that the mercury flows along a flattened helical or zig-zag path
extending alternately through the decomposing space and the combining space.
This arrangement is especially suitable for use in existing electrolytic apparatus
which work with diaphragins because it is merely necessary to insert the wall A³
with channel in place of the diaphragm.
In the case of very large apparatus it will be advantageous to employ the
In this arrangement the
construction of apparatus shown in Figs. 9 10 and 11.
channel portions a a and b, bare, arranged respectively in separate
decomposing and combining vessels the said chaunel-portions being connected
together by means of bent pipes situated outside of and between the said
5 vessels.
Thus the mercury supplied from the pipe 7, circulates in semi-convolutions

page_text: between three electrodes of opposite poles, and is in this way subjected on both
sides ("irradiated " on both sides) to the action of these electrodes, so that only
half the quantity of mercury is required, whilst the output is the same as in the
arrangements herein before described.
Dated this 17th day of December 1894.
Method of and Apparatus for Effecting Electrolysis.
I, Dr. CARL KELLNER of IX Wasagasse No. 29, Vienna, Austria, and
Cellulose Works, Hallein, Austria, Doctor of Philosophy and Director of the
Kellner-Partington Paper-pulp Company, Limited, 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 :--
As is well known, the vertical arrangement of electrolytic apparatus is for many
reasons to be preferred to the horizontal arrangement. This is especially the case
with apparatus in which mercury is employed as an electrode, because :-(1) It is
difficult to place and maintain large and heavy apparatus horizontal with such
accuracy as to cause the bottom to be everywhere uniformly covered with a thin
layer of this expensive metal. (2) It is difficult to act electrically upon large
horizontal surfaces uniformly, and experience shows that an amalgam of an alkali-
metal decomposes the water of the electrolyte at the places of small current density,
which in the case of the electrolysis of the chlorides of the alkali-metals causes the
formation of hypochlorites. (3) The output-capacity of horizontal apparatus is
restricted by difficulties in respect of construction and material, many contacts,
large space, and numerous apparatus being required. (4) The surface of the
mercury, which alone is effective or operative, is rendered impure by the anodes
arranged above it. (5.) In practical working, it is very inconvenient to keep large
quantities of mercury in constant uniform movement.
It has heretofore been proposed to employ mercury in a vertical or inclined form
as a cathode for instance, by causing it to trickle in thin sheets or streams down
over vertical or slightly inclined amalgamated metallic surfaces constituting the
cathode, or by drawing amalgamated metallic bodies, for example bands, and strips
of sheet metal through mercury. But all these apparatus are so complicated, and
their output is so small, as to render them unsuitable for use for working on a
large scale.
Now the present invention is designed to provide means for enabling the complete
decomposition of metallic chlorides to be effected electrolytically, with the
practically complete utilization of the electro chemical equivalent of energy, by
means of vertically arranged extremely simple, durable and reliably working
apparatus without the use of a porous diaphragm or partition.
According thereto the mercury cathode is employed in the form of narrow strips,
which are formed by a system of channels, and are compelled to circulate in a
helical or zig-zag path or paths about the anode or anodes, whilst they are being
continuously freed, in a cell separated from the decomposing chamber, from the
kation they have taken up in their course. By employing this method it has also
been rendered possible to construct apparatus of any desired output capacity. The
quantity of mercury required is comparatively small in consequence of the high
current density that is attainable therewith; and the raising apparatus or operation
is simple because it is sufficient, however large the apparatus may be, to raise up

page_text: to the initial convolution of the helical path, a stream of mercury corresponding in
cross section to that of the stream flowing through the said helical path at any
given point.
In carrying this method into practice, the apparatus illustrated by way of
example in a number of modified forms in the drawings filed with my Provisional
Specification, may be employed.
In these drawings,
Fig. 1 illustrates in vertical section and Fig. 2 partly in plan and partly in
horizontal section, an apparatus constructed of cylindrical shape.
Figs. 3, 4 and 5, are respectively a perspective view, a part vertical section, and
a part horizontal section showing a cylinder provided with helical channels for
guiding the mercury strip or stream.
Figs. 6, 7 and 8 are respectively an elevation partly in section, a vertical section,
and a horizontal section illustrating another construction of apparatus of flat
shape, adapted to be inserted into existing electrolytic apparatus, in place of a
diaphragm.
Figs. 9 and 10 show respectively in horizontal and vertical section, another
arrangement of apparatus in which the strip-like layer of mercury, in contra-
distinction to the two forms of apparatus shown in Figs. 1 to 8 inclusive, is subjected
to action or influence on both sides (is "irradiated" from both sides), and is
consequently adapted to work with a large current density.
Fig. 11 shows partly in elevation and partly in section, a portion of the channel
used in the apparatus shown in Figs. 9 and 10.
4, 1, 611
'
In the apparatus illustrated in Figs. 1-5 inclusive, A is a cylinder composed of
material such as porcelain or stoneware provided with numerous helical
channels a, a', all
of which only a few are shown for the
sake of clearness, and through which the mercury flows in the form of a stream,
the parts of the mercury stream in the several channels constituting strips. The
channels are arranged on the cylinder A. (Fig. 3) in such a manner that the first,
third, fifth and so on convolutions, that is to say, the channels forming the odd-
numbered convolutions of the helix, are situated on the inner surface of the
cylinder, whilst the channels forming the second, fourth, sixth and so on, or even-
numbered convolutions, are situated on the outer surface of the cylinder. The
internal channels situated in the electrolytical decomposing cell communicate with
the external channels, situated in what I call the combining or forming cell, each
by means of an opening or slit e formed in the wall of the cylinder.
In the cylinder A. to the uppermost channel a of which the mercury is supplied
through a pipe q, there is inserted a suitable anode (or anodes) B preferably of
cylindrical shape, which is filled with the salt, in a solid state, to be decomposed,
so that this salt cannot enter the mercury channels, but, by passing from below the
anode, into the clectrolyte around the same, will become dissolved therein and so
maintain the strength thereof. The whole is arranged in a vessel C which contains
the substance (water or other fluid reagent) with which the separated kation is to
be combined, and which is closed by a cover d. is the inlet pipe for the liquid
reagent, and and are gas exit pipes.
The anode B is connected to the positive pole of an electric generator, and the
mercury is connected with the negative pole thereof.
As the resistance of the long stream of mercury, with considerable current con-
sumption, would be very appreciable, it is advisable to connect the stream of
mercury at various points in its length with the negative pole of the electric
generator. For this purpose the vessel C is or may be made of metal, for example
iron, and connected electrically at various points with the mercury by means of the
wires n, the vessel itself being connected to a wire n', as shown on the left band
side of Fig. 1 by which it is placed in electrical connection with the negative pole
of the electric generator.
But if electricity produced by the combination of the kation dissolved in the
mercury kathode, with the liquid re-agent in the vessel C, is to be utilized, then,

page_text: as shown on the right hand side of Fig. 1, the wires are connected to form a
common return lead n² to the negative pole of the electric generator, another lead m
extending from the vessel C. The mercury in the external channels, and the
said vessel, form in this case the electrodes of a secondary element which can be
advantageously used for supplying current to another electrolytic apparatus, or
for relieving the main source of current supply. If it is mainly desired to effect
a decomposition of the mercury amalgam that shall be capable of regulation, all
the mercury strips are again connected by a lead with the negative pole of the
dynamo machine, and into this lead there is included a resistance W, Fig. 9, and
beyond the latter a connection is made with the conducting vessel C.
In this way
there is formed a short-circuited element which promotes the formation of caustic
soda. The efficiency of this element, that is to say, the speed of the decomposition
of the amalgam, may be regulated by varying the resistance.
The mode of operation of the apparatus is as follows:-
As
Assuming for example that common salt is to be decomposed with the object
of producing simultaneously by electrolysis, caustic soda, and chlorine gas, then
a solution of common salt is placed in the decomposing vessel A, and water in the
combining vessel C and mercury is poured into the topmost inner channel a.
soon as the electric circuit is completed, sodium will be separated from the solution
of common salt contained in the decomposing vessel, and will unite with the
mercury kathode, but during the passage of the mercury amalgam through the
second helical convolution & situated on the outside of the vessel A, the above
mentioned sodium will be acted upon by water contained in the combining vessel C
with formation of caustic soda and liberation of hydrogen. The mercury freed
from sodium then passes at once into the next inner helical convolution a', again
amalgamates with sodium. carries the same into the outer helical convolution in
the combining vessel where it yields up the sodium as before, and so on, passing
finally out of the apparatus in a pure condition by a pipe q' to a pump p or other
suitable raising device by which it is again delivered to the pipe 7 and thus to the
topmost inner channel a for re-use. The concentrated solution of caustic soda is
drawn off from the vessel C through a pipe p'. The hydrogen escapes through the
pipe, whilst the chlorine escapes through the pipe 2, the gases being conducted
by these pipes to the place where they are to be utilized.
If instead of water, a solution of sodium nitrate be used in the combining vessel C,
ammonia gas will be liberated instead of hydrogen.
The hereinbefore described arrangement of vessel A with mercury channels,
serves to provide a fluid tight division between the interior of the concentric
decomposing and combining vessels. But in cases where no value will be attached
to this arrangement, there may be employed in place of the cylinder A, an
insulating wall A' for separating the two spaces, as shown in Figs. 6 7 and 8.
This wall is provided on both sides with the oppositely inclined channels a¹
b, which are connected together by means of slots c so that the mercury flows
along a flattened helical or zig-zag path extending alternately through the
decomposing space and the combining space.
a,
.
This arrangement is especially suitable for use in existing electrolytic apparatus
which work with diaphragms, because it is merely necessary to insert the wall A¹
with channel in place of the diaphragm.
and 6
In the case of very large apparatus it will be advantageous to employ the con-
struction of apparatus shown in Figs. 9 10 and 11. In this arrangement the
channel portions a a¹
are arranged respectively in separate
decomposing and combining vessels, the said channel-portions being connected
together by means of bent pipes / situated outside of and between the said vessels.
Thus the mercury supplied from the pipe g, circulates in semi-convolutions between
three electrodes of opposite or positive polarity and is in this way subjected on both
sides ("irradiated " on both sides) to the action of these electrodes, so that only
half the quantity of mercury is required, whilst the output is the same as in the
arrangements hereinbefore described.

page_text: Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed 1 declare that what I
claim is :-
:-
1. Effecting the electrolysis of metallic salts by means of a mercury electrode,
that is caused to pass in the form of narrow strips or streams formed by a helical
zig-zag or equivalent winding channel, alternately through an electrolytical decom-
posing chamber and a combining or forming chamber, so that it acts in places as a
kathode, and carries the amalgam immediately after its formation in the decomposing
chamber, into the combining or forming chamber, and then, after the kation has
been separated therefrom, it may be with the production of an electric current,
again passes into the decomposing chamber for the purpose of forming fresh
amalgam, and so on, as set forth.
2. For carrying out the method specified in the preceding claim, an apparatus
comprising a helical or zig-zag mercury channel having its convolutions or
parts a bab arranged alternately on opposite sides of a cylindrical or flat wall and
connected in succession by means of slots formed in the said wall substantially as
described.
3. An arrangement of the apparatus specified in Claim 2, in which the con-
volutions of the mercury channel are arranged in decomposing and combining or
forming vessels that are separated from each other, the portions of the said channel
within the two vessels being connected by means of bent pipes situated outside
of the said vessels and anodes being arranged on opposite sides of the mercury
cathode within the decomposing vessel, substantially as herein described.
4. Apparatus of the kind specified in Claims 2 and 3, in which the strips of
mercury are connected on the one hand with the negative pole of an electric
generator and on the other hand with the combining or forming vessel C through a
circuit external to the latter, so that the formation of caustic soda from sodium
amalgam in the strips of mercury is promoted after the manner of the process
in a short-circuited element, and in which the action of this element can be
regulated by means of a resistance W included in the portion of the circuit outside
the said element substantially as described.
5. The improved electrolytic apparatus constructed, arranged, and operating as
hereinbefore described, with reference respectively to and shown in Figs. 1 to 5
inclusive; in Figs. 6 to 8 inclusive; and in Figs. 9 to 11 inclusive of the drawings
berein referred to.
Dated this 16th da of October 1805