Improved Means and Apparatus for Separating Alkaline and Earthy Metals and other Products from the Salts of such Metals, or from other Substances containing them.
Year: 1890

page_text: Date of Application, 19th Dec., 1890
Complete Specification Left, 18th Sept., 1891-Accepted, 24th Oct., 1891
PROVISIONAL SPECIFICATION.
Improved Means and Apparatus for Separating Alkaline and Earthy
Metals and other Products from the Salts of such Metals, or from
other Substances containing them.
We, GEORGE JONES ATKINS, of Ruskin Road, Tottenham, in the County of
Middlesex, Electro-metallurgist, and EDWARD APPLEGARTH, of Copthall
Buildings, in the City of London, Mining Engineer, do hereby declare the nature
of the said invention to be as follows:-
This invention relates to improved means and apparatus for separating alkaline
and earthy metals and other products from the salts of such metals, or from other
substances containing them, as for example for the separation of sodium and
sodium hydrate from sodium chloride, or from the soda waste of paper works
technically called "black liquor."
It is well known that when a solution of the chloride of an alkaline or earthy
metal is subjected to electrolysis, it is split up, chlorine and oxygen being liberated
at the anode or positive pole, while the metal and hydrogen are liberated at the
cathode or negative pole of the chamber or cell in which the decomposition takes
place. It is further known that if the cathode is composed of mercury, the metal
and hydrogen deposited therein form an amalgam with the mercury, but heretofore,
so far as we are aware, it has not been found possible to apply the electrolytic
process to the purpose of separating the said metals from their salts, or from other
substances containing them, because the counter electro-motive force, set up at the
cathode by the metal and hydrogen, has been so great that the electro-motive force
required to effect the decomposition of the solutions and to deposit the metal in
opposition to the said counter electro-motive force has been out of all proportion to
the industrial result obtained.
The object of the present invention is to provide means and apparatus whereby
electrolysis can be utilized for obtaining, on a practical scale, the said metals, or
compounds thereof. with other bodies, from substances containing them without
requiring the expenditure of so great an amount of power as would be required by
the use of ordinary electrolytic apparatus.
For this purpose we employ a novel method of using the mercury into which the
inetal and hydrogen are deposited at the cathode. This method consists in causing
the mercury to flow in a thin continuous stream or lamina over the surface of the
cathode (which may or may not be itself amalgamated with mercury) while
the electrolytic process is going on, that is to say while the metal is being deposited
in the moving mercurial cathode. The mercury and the metal thus combined
form an amalgam which flows away, while still forming a part of the cathode and
while still subjected to the action of the electric current, into a separate chamber
or reservoir where it is removed from the oxidizing action of the solution or other
oxidizing agent, and from which chamber or reservoir it may be removed continuously,
or from time to time, to be treated for the separation of the metal, or metal and
hydrogen, from the mercury, which can then be used again and again indefinitely
as the flowing cathode. The hydrate of the metal, formed and held in solution
in the decomposition chamber or cell, can also be continuously or periodically
removed along with the hydrogen gas given off. By this means, the metal is
removed continuously from the surface of the cathode, and the resistance set up by
the gaseous hydrogen and the above mentioned counter-electro-motive force of the
metal are so much reduced that the power required to effect the decomposition and

page_text: to overcome the said resistance sand counter electro-motive force is so materially
reduced, as compared with what is required in the ordinary arrangements above
referred to, that the application of the electrolytic process is not only made
possible but can be made to produce highly economical results.
The apparatus for utilizing the above described. flowing or moving cathole may
be varied according to circumstances. One arrangement that we have found
suitable and convenient is of the following character A vertical cylinder of
metal, amalgamated on its internal surface with mercury in the usual way, is
provided at its lower end with an outlet passage governed by a stop cock or valve
which communicates with a vessel or reservoir to receive the metal and hydrogen
amalgam as above described. The upper end of the said cylinder is shaped as a
funnel or hopper and has inserted into it the lower end of a second cylinder.
A narrow annular,space is. left between the outside of the inner cylinder and the
inside of the outer one, so that when mercury is allowed to run from an overhead
tank into the said funnel or hopper it finds its way through the annular space, and
coming in contact with the amalgamated surface of the outer. cylinder, flows
comparatively slowly down over the said amalgamated surface and through the
aforesaid outlet passage to the receiving vessel or reservoir. The aforesaid vertical
metallic cylinder forms a stationary cathode chamber which contains a suitable
solution such as that of sodium chloride for example. In the centre of this cathode
cylinder is inserted or suspended an anode pole surrounded by a hose pipe, such as
that used for fire hose, sinade of closely woven hemp or other itextile material,
closed or not at the lower end. This hose pipe of textile material is preferably
treated with silicate of soda in order to preserve-it more or less from the rotting
action of the solution. The carbon or other suitable anode is placed in the said
hose pipe and may consist of a hollow stem or pipe having rings of carbon threaded
-thereon. The materialito be decomposed, chloriderofisodium solution for example,
is passed through this pipe to the bottom of the hose pipe and while gradually
rising to the top thereof, round the external surface of the anode;-is subjected
to electrolytic action, the bulk of the sodium passing through-the-sides-of-the
hose pipe to the cathode, and the-solution, more less deprived of its sodium,
overflows at the top of the those pipe and passes-off,-together with the liberated
|_ chlorine gas, either to waste, or to be utilised for any purpose to which the said
solution or gas may be applicable. The solution in the cathode cylinder, external-
to the hose pipe, gradually becomes charged with sodium hydrate and may be
withdrawn continuously or periodically-along-with-the-liberated hydrogen gas,
from the top of the cathode cylinder, water being admitted at the opposite
end of the cathode cylinder to take the place of the sodium hydrate solution
drawn off.
To facilitate the collection and removal of chlorine and hydrogen gases from the
cathode and anode chambers, respectively, these may the furnished with covers
provided with outlet pipes leading to suitable chambers or gas.holders.
We sometimes make the anode chamber of ordinary porous materialiinstead of
the woven hose pipe as above described, and when the: chamber is of such a depth
that it is not practicable to make it in one piece. of porous material, ,we make it of
several separate lengths placed one on the other and jointed together- by.india-
rubber bands placed over the joints or otherwise.
The above arrangement of apparatus is mentioned merely by way of example; it
is obvious that any arrangement of apparatus which will allow of the use of a' flowing
or moving:mercurial cathode may be employed.
By the above arrangements we are enabled to bring the cathode and anode very
near to each other, so that the stratum of solution between them is comparatively
thin; therefore the resistance of the liquid to the passage of the electric current is
reduced to a minimum; further. by the immediate withdrawal of the weakened
solution from the anode cell, the resistance to the passage of the current through
the liquid is maintained at a minimum. And by the use of the flowing mercurial

page_text: cathode, the counter electro-motive force, due to the metal and hydrogen deposited
therein, is also reduced to a minimum.
Dated thin 10th 1...
Desemba 1000
COMPLETE SPECIFICATION.
Improved Means and Apparatus for Separating Alkaline and Earthy
Metals and other Products from the Salts of such Metals, or from
other Substances containing them.
We, GEORGE JONES ATKINS, of Ruskin Road, Tottenham, in the County of
Middlesex, Electro-metallurgist, and EDWARD APPLEGARTH, of Copthall
Buildings, in the City of London, Mining Engineer, do hereby declare the nature
of the said invention and in what manner the same is to be performed, to be
particularly described and ascertained in and by the. following statement, that
is to say :-
This invention relates to improved means and apparatus, for separating alkaline
and earthy metals and other products from the salts of such metals or from other
substances containing them, as for example, for the separation of sodium and
sodium hydrate from sodium chloride, or from the soda waste of paper works
technically called "black liquor."
It is well known that when a solution of the chloride of an alkaline or earthy
metal is subjected to electrolysis it is split up, chlorine and oxygen being liberated
at the anode or positive pole, while the inctal and hydrogen are liberated at the
cathode or negative pole of the chamber or cell in which the decomposition takes
place. It is further known that if the cathode is composed of mercury, the metal
and hydrogen deposited therein form an amalgam with the mercury, but heretofore,
so far as we are aware, it has not been found possible to apply the electrolytic
process to the purpose of separating the said metals from their salts or from other
substances containing them, because the counter electro-motive force set up at the
cathode by the metal and hydrogen has been so great that the electro-motive force
required to effect the decomposition of the solutions and to deposit the metal in
opposition to the said counter electro-motive force has been out of all proportion to
the industrial result obtained.
The object of the present invention is to provide means and apparatus whereby
electrolysis can be utilized for obtaining on a practical scale the said metals, or
compounds thereof with other bodies, from substances containing them without
requiring the expenditure of so great an amount of power as would be required by
the use of ordinary electrolytic apparatus.
For this purpose we employ a novel method of using the mercury, into which the
metal and hydrogen are deposited, at the cathode. This method consists in causing
the mercury to flow in a thin continuous stream or lamina over the surface of the
cathode (which may or may not be itself amalgamated with mercury) while
the electrolytic process is going on, that is to say, while the metal is being
deposited in the moving mercurial cathode. The mercury and the metal thus
combined, form an amalgam which flows or moves away while still forming a part
of the cathode, and while still subjected to the action of the electric current into a
separate chamber or reservoir, from which the said amalgam may be removed
continuously, or from time to time, to be treated for the separation of the metal, or
metal and hydrogen from the mercury, which can then be used again and again
indefinitely as the flowing or moving cathode. The hydrate of the metal formed
and held in solution in the decomposition chamber or cell, can also be continuously
or periodically removed along with the hydrogen gas given off. By this means the

page_text: metal is removed continuously from the surface of the cathode, and the resistance
set up by the gaseous hydrogen and the abovementioned' counter electro-motive
force of the metal are so much reduced that the power required to effect the
decomposition and to overcome the said resistance and counter electro-motive force
is so materially. reduced as compared with what is required in the ordinary
arrangements above referred to, that the application of the electrolytic process is
not only made possible, but can be made to produce highly economical results.
The apparatus for utilizing the above described flowing or moving cathode may
be varied according to circumstances. One arrangement that we have found
suitable and convenient is shown in the accompanying sheet of drawings, in which
Figure 1 is a vertical section of the electrolytic apparatus, Figure 2 a plan of same,
Figure 3 a section taken on line 1-1 of Figure 1 and Figures 4 and 5 views of
modified arrangements. A vertical cylinder of metal A, preferably amalgamated
on its internal surface with mercury in the usual way, is provided at its lower end
with an outlet passage B, governed by a stop cock or valve or provided with a
syphon B which communicates with a suitable vessel or reservoir, not shown in the
drawings, to receive the mercury and amalgam as above described.
The upper
end of the said cylinder is shaped as a funnel or hopper C, and has inserted into it
the lower end of a second cylinder D. A narrow annular space is left between the
outside of the inner cylinder D and the inside of the outer one A, so that when
mercury is allowed to run from an overhead tank through the pipe E into the said
funnel or hopper it finds its way through the annular space and coming in contact
with the amalgamated-surface of the outer cylinder A, flows comparatively slowly
down over the said amalgamated surface and through the aforesaid outlet passage B
to the receiving vessel or reservoir. The aforesaid vertical metallic cylinder A.
forms a stationary cathode chamber, connected by a conductor A with a dynamo
or other suitable source of electricity. This cathode chamber contains a suitable
-solution-such as that of sodium chloride for example. In the centre of this cathode
cylinder is inserted or suspended an anode pole of carbon; for example,
surrounded by a hose pipe G such as that used for fire hose made of closely woven
hemp or other textile material preferably closed at the lower end. This hose
pipe G of textile material is preferably treated with silicate of soda in order to
preserve it, more or less, from the rotting action of the solution-The-carbon-or-
other suitable anode F is placed in the said hose pipe G and is connected by a
-conductor-with-the-dynamo-or-other-suitable_source_of_electricity. The anode
may consist of a hollow stem or pipe 1 having rings of carbon threaded thereon or
being otherwise surrounded with the carbon 1. The material to be decomposed,
chloride of sodium solution for example, is passed through this pipe H to the
bottom of the hose pipe G, and while gradually rising to the top thereof round the
external surface of the anode F, is subjected to electrolytic action, the bulk of
the sodium passing through the sides of the hose pipe to the cathode A and the
solution, more or less deprived of its sodium overflows at the pipe I near the top
of the hose pipe G and passes, off, together with the liberated chlorine
gas, either
to waste or to be utilized for any purpose to which the said solution or gas may be
applicable, for example the solution may; after-being strengthened, be again used
in the electrolytic apparatus. The solution in the cathode cylinder A external to
the hose pipe G gradually becomes charged with sodium hydrate and may be
withdrawn continuously, or periodically, along with the liberated hydrogen gas by
the pipe J from the top of the cathode cylinder, water being admitted through the
pipe K at the opposite end of the cathode cylinder to take the place of the sodium
hydrate solution drawn off.
To facilitate the collection and removal of chlorine and hydrogen gases from the
cathode and anode chambers respectively, these may be furnished with covers
provided with outlet pipes leading to suitable chambers or gas holders.
.
We sometimes separate the cathode from the anode by means of ordinary porous
material instead of the woven hose pipe above described, and when such
porous separating material is of such a depth that it is not practicable to make it

page_text: in one piece, it may be made of several separate lengths placed one on the other
and jointed together by india-rubber bands placed over the joints, or otherwise.
In order to retard the descent of the mercury over the surface of the cathode A
and to assist in maintaining the latter in a constantly, amalgamated condition, the.
said cathode may be made with horizontal corrugations as shown in Figure 4 for
example, each corrugation A2 forming a gutter or ledge containing a small portion
of mercury which is gradually washed down by the mercury trickling over the
edge of each gutter. The time of descent of the mercury.and amalgam from
the top to the bottom of the cathode is by this means considerably prolonged.
It will be understood that the cathode chamber A may be of rectangular or
other suitable shape instead of round as shown in Figures 2 and 3, and that instead
of being placed in a vertical position the apparatus may be inclined at any desired
angle, and instead of the mercury being supplied at the upper end of the cathode
and caused to flow by its gravity over the acting surface thereof, the-cathode itself
may be moved by any suitable mechanical means so as to cause a film or lamina of
mercury to move with it, as for example in the arrangement shown diagrammatically
in Figure 5, in which A³ represents an electrolytic cell constructed of any suitable
material and having at bottom a tank containing mercury A
This tank may
be provided with a syphon B' for removing the mercury and amalgam as in the
apparatus shown in Figure 1. F is the anode pole and G a porous partition.
The cathode A consists of an endless band of sheet copper for instance, which
passes over the roller A' and under the roller A', the lower part of the said band
or sheet of copper being immersed in the mercury A. Rotary motion being
imparted to the roller A', the band A, the surface of which is amalgamated is
caused to pass through the said mercury A and a thin film or lamina thereof is
carried up by the band and receives the metal and hydrogen in the same manner
as the flowing mercury in Figure 1. Any suitable arrangement of scraper or
brush may be employed to remove superfluous mercury or amalgam from the band
as the latter inoves. The said band A may be corrugated as illustrated in Figure 4,
and the electric connection thereof with the dynamo or other source of electricity
may be effected by a contact brush or any other suitable means.
The above arrangements of apparatus are mentioned merely by way of example;
it is obvious that any arrangements of apparatus which will allow of the use of a
flowing or moving mercurial cathode may be employed.
By the above arrangements we are enabled to bring the cathode and anode very
near to each other, so that the stratum of solution between them is comparatively
thin, therefore the resistance of the liquid to the passage of the electric current is
reduced to a minimum; further by the immediate withdrawal of the weakened
solution from the anode cell the resistance to the passage of the current through
the liquid is maintained at a minimum. And by the use of the flowing mercurial
cathode, the counter electro-motive force due to the metal and hydrogen deposited
therein is also reduced to a minimum.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, we declare that what
we claim is :-
First The improved means for separating alkaline and earthy metals, and other
products from the salts of such metals, or from other substances containing them,
which consist in subjecting a solution of such salt or other substance to electrolysis
in electrolytic apparatus, the cathode pole of which is composed more or less of a
flowing or moving surface or body of mercury, substantially as hereinbefore
described.
Second In electrolytic apparatus for separating alkaline and earthy metals,
and other products from the salts of such metals, or from other substances containing
them, the method of employing mercury at the cathode pole of such apparatus,
which consists in causing the mercury to flow or move over, on, or with the surface
of the cathode pole, substantially as herein before described.

page_text: Third In electrolytic apparatus for separating alkaline and earthy metals, and
other products from the salts of such metals or from other substances containing
them, constructing the cathode pole with means for causing a thin stream or lamina
of mercury to flow or move over, op, or with, the acting surface of the said cathode
pole, substantially as hereinbefore described and illustrated in the drawings.
Dated this 18th day of Sentember 1891
G. J. ATKINS.
E. APPLEGART.
W. H. Beck,
Per G. E. Gunyon,
115, Cannon Street, London, E.C., Agent.