Improvements in Electrolytic Apparatuses for Extracting Metals Lighter than the Electrolyte.
Year: 1899

page_text: Date of Application, 5th June, 1899
Complete Specification Left, 2nd Mar., 1900-Accepted, 14th Apr., 1900
PROVISIONAL SPECIFICATION.
Improvements in Electrolytic Apparatuses for Extracting Metals
Lighter than the Electrolyte.
A communication by HERMANN BECKER, Chemical Engineer, of 5, Rue Guy-
Patin, Paris, in the Republic of France.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of the Agency for Foreign
Patent Solicitors, 6, Lord Street, Liverpool, and 6, Bank Street, Manchester, both
in the County of Lancaster, 118, New Street, Birmingham, in the County of
Warwick and 322, High Holborn, in the County of Middlesex, Civil Engineer,
do hereby declare the nature of this invention to be as follows:-
The present invention relates to an apparatus intended for the extraction of
metals which, in the electrolysis of their salts, or oxides, in fusion, rise to the
surface of the liquid mass, and it consists of an apparatus which enables the
metals obtained to be easily collected, whilst preserving them from contact with
air and preventing them from being re-dissolved in the electrolyte after having
quitted the cathode. This result is obtained by means of a collecting cone of
metal suspended in the electrolyte above the cathode and which in electric
communication with the cathode.
The apparatus is composed of a metal vessel lined or otherwise, the bottom of
which is provided with a large pipe for giving passage to a rod, on the end of
which the cathode proper is fixed. The lower end of the pipe is closed by means
of a cylindrical piece or stopper of insulating material such as lava, porcelain,
fireclay or the like, perforated in the centre with a hole, through which the rod
passes. The pipe is surrounded or enclosed by a refrigerating jacket or sleeve
having a double casing or by any other suitable refrigerating arrangement.
The refrigeration of the pipe has for its object to render pasty, and if possible
solid, the electrolyte contained therein, so as to avoid any leakage between the
said tube and the plug or stopper. The cathode is formed of a metallic piece,
having a slightly tapering shape, so as to facilitate the rise of globules of metal in
a straight line to the surface of the bath, which globules of metal form on the
surface of the said cathode, but it may assume any other suitable form answering
the same purpose.
In one form of the apparatus, a cathode may be employed of a special form.
comprising a certain number of rectangular, square or round bars, cast in one
piece with the base, which is fixed to the end of the rod. This arrangement allows
of the cathode surface being considerably increased, and consequently of the
metal produced being concentrated in a limited space at the surface of the bath.
The anode of annular form entirely surrounds the cathode. It may be in one
or more pieces. It is made of agglomerated retort carbon or of metal, according

page_text: to the nature of the electrolyte. This anode is suspended by one or more rods
which serve as conductors and which are fixed to the outer surface of the anode,
or the constituent parts of the anode, in such a way that there is a greater space
between the rod of the anode and the cathode than between the anode itself and
the cathode. The anode must not be immersed down to the bottom of the vat,
it must be at the most, at the same height as the cathode.
Above this cathode there is suspended a metallic piece of conical form, insulated
from the apparatus, and which is designed to collect the globules of metal which
rise to the surface of the electrolyte.
This collecting cone has the form of a very wide recessed shade or reflector, and
is provided with a vertical or approximately vertical flange or raised edge. It has
a centre tube of sufficiently large diameter and having a thick wall. This tube
is closed by a heavy hinged lid forming a valve, or in any other suitable manner,
and is provided with a discharge pipe slightly inclined, which passes through the
wall of the electrolytic vessel. At the point where the discharge pipe passes
through the wall of the vessel, it is insulated by means of a little tube or collar
of asbestos or porcelain.
The diameter of the collecting cone must be a little greater than that of the
cathode, and smaller than the diameter of the annular anode, so that the globules
of metal which are detached from the cathode all come under the collecting cone,
and the gases which are released at the anode, can pass outside this cone.
The collecting cone must not be immersed too deeply in the electrolyte, so
that the latter can not extend above the edge and cover the collecting cone, the
upper face of which is always in contact with the air, thus preventing any
abnormal increase in the temperature. When the temperature of the electrolyte
with which the operation is carried out is too high, the collecting cone may be
chilled by causing cold air to arrive therein, or by allowing water to drop therein,
which water is immediately volatilized, or even by any other suitable system of
refrigeration.
In some cases a conical collector may be employed in the wall of which a refri-
gerating gas or liquid may be caused to circulate. This refrigeration of the
collecting cone has for its object to lower the temperature of the liberated metal
sufficiently to prevent its distillation and its oxidation on its exit from the dis-
charge pipe. The collecting cone is connected in shunt with the negative con-
ductor by means of a resistance calculated in such a way that only a very small
fraction of the total current can pass through it. It therefore plays the part of
an auxiliary cathode so that the metal liberated at the principal cathode, and
which rises into the collecting cone, becomes again negative during the time that
it occupies in sliding over the lower face of the collecting cone and rising
in the pipe which conveys it to the discharge opening. The passage of the metal
from the principal cathode to the auxiliary cathode is so rapid that it cannot be
re-dissolved in the electrolyte, and once it comes against the auxiliary cathode,
the metal forms part of the latter, so that it cannot be attacked by the bath. It
must also be understood that the particular form of the collecting cone described
is, not indispensable, as this part inay assume any other suitable form fulfilling
the same object.
If it be desired to collect the gas which is liberated at the anode, it is sufficient
to cover the apparatus with a suitable lid or cover provided with a discharge pipe.
The apparatus is mounted on a frame or foundation of cast metal, bricks or the
like, of any suitable form.
In this electrolytic apparatus the electrolyte is maintained in fusion by the heat
developed by the passage of the current which enables only the central part of the
mass to be kept liquid and ensures great durability for the apparatus.
The metal which emerges by the discharge pipe having been brought to a
suitable temperature, by one of the systems of refrigeration herein before described,
may, if not very oxidizable, be received in an ingot mould of any suitable form
placed beneath the end of the discharge pipe. If the metal is too oxidizable, an

page_text: ingot mould is employed which is almost hermetically closed, and provided at
its upper part with an opening, in which the end of the discharge pipe can enter.
Dated this 3rd day of June 1899.
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.
Improvements in Electrolytic Apparatuses for Extracting Metals
Lighter than the Electrolyte.
A communication by HERMANN BECKER, Chemical Engineer, 5, Rue Guy-Patin,
Paris, in the Republic of France, a citizen of the Swiss Republic.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., Agent for Foreign Patent
Solicitors, of 6, Lord Street, Liverpool, and 6, Bank Street, Manchester, both in
the County of Lancaster, 118, New Street, Birmingham, in the County of
Warwick, and 322, High Holborn, in the County of Middlesex, Civil Engineer,
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:-
The present invention relates to improvements in an apparatus intended for the
extraction of metals which rise to the surface of the liquid mass in the electrolysis
of their salts, or oxides, in fusion.
This apparatus is shown in the accompanying drawings,
Figure 1 being a vertical section,
Figure 2 a detail view of a special form of cathode and
Figure 3 a detail view of a collecting cone.
The apparatus is composed of a metal vessel A, lined or otherwise, the bottom
of which is provided with a large pipe a giving passage to a rod b on the end of
which the cathode proper B is fixed. The lower end of the pipe a is closed
by means of a cylindrical piece or stopper a¹ of insulating material such as lava,
porcelain, fire clay or the like perforated in the centre with a hole, through which
the rod b passes. The pipe a is surrounded by a jacket or sleeve h having a double
casing in which a refrigerating liquid or gas is caused to circulate, but the sleeve
with its double casing may if desired be replaced by any other suitable refrigerat-
ing arrangement. If the temperature of the electrolyte be not too high and
the length of the pipe a be sufficiently great the refrigerating arrangement may
be dispensed with.
The refrigeration of the pipe a has for its object to render the electrolyte con-
tained therein, pasty and if possible solid, so as to avoid any leakage. The
cathode B is formed of a metallic piece having a slightly tapering shape so as to
facilitate the rise in a straight line to the surface of the bath, of the globules
of metal which form on the surface of the cathode.
The cathode of special form shown in Figure 2 consists of a certain number
of rectangular, square or round bars b¹ çast in one piece with the base 6ª which
is fixed on the end of the rod b. This arrangement allows of the cathode surface
being considerably increased and consequently of the metal produced being con-
centrated in a limited space at the surface of the bath.
The anode C of annular form entirely surrounds the cathode. It may be in one

page_text: or more pieces. It is made of agglomerated retort carbon or of metal, according
to the nature of the electrolyte. This anode is suspended by one or more
rods which serve as conductors and which are fixed to the outer surface of the
anode or the constituent parts of the anode in such a way that there is greater
space between the rod of the anode and the cathode than between the anode itself
and the cathode.
The anode must not be immersed down to the bottom of the vat, it must be at the
most at the same height as the cathode. A few centimetres above this cathode a
inetallic piece of special form which may be called a collecting cone in view of the
conical form of its essential part and the object which it has to fulfil, is
suspended in any suitable manner and insulated from the apparatus, and the
object of this collecting cone is to collect the globules of metal which rise to
the surface of the liquid mass and to cause the metal to flow out of the vat.
The conical form has been preferably selected because that is the one which
has yielded the best results in the experiments, but it must of course be under-
stood that any other suitable form realising the same advantages may be employed.
This collecting cone D has the form of a wide recess, shade or collector and is
almost flat. It is provided with a vertical or approximately vertical flange d
inclined towards the centre. It has a central tube e of somewhat large diameter
and having a thick wall. This tube e is closed by a heavy hinged lid or in
any other suitable manner, and is provided with a discharge pipe f. slightly
inclined, which passes through the wall of the electrolytic vessel. At the point
where the discharge pipe passes through the wall of the vessel it is insulated by
means of a little tube or collar f¹ of asbestos or porcelain. The diameter of the
collecting cone must be a little greater than that of the cathode B and much
smaller than the diameter of the annular anode, so that the globules of metal
which are detached from the cathode all come under the collecting conc and the
gases which are released at the anode can pass outside this cone.
The collecting cone must not be immersed too deeply in the electrolyte so that
the latter can not extend above the edge and cover the collecting cone, the
upper face of which is always in contact with the air, thus preventing any
abnormal increase in the temperature. When the temperature of the electrolyte
on which the operation is carried out, is too high, the collecting cone may be
cooled by causing cold air to flow therein or by allowing water to fall thereon
drop by drop, which water is immediately volatilized, or even by any other
system of refrigeration.
The conical collector shown in Figure 3 allows of a refrigerating gas or liquid
being circulated in its wall. This refrigeration of the collecting cone has for its
object to lower sufficiently the temperature of the liberated metal so as to prevent
its distillation and its oxidation on its exit from the discharge pipe.
The collecting cone is connected in shunt with the negative conductor 9 by
means of a resistance calculated in such a way that only a very small fraction
of the total current can pass through it. It plays therefore the part of an auxiliary
cathode, so that the metal liberated at the principal cathode and which rises into
the collecting cone becomes again negative during the time that it occupies in
sliding over the lower face of the collecting cone and rising in the pipe which
conveys it to the discharge opening. The passage of the metal from the principal
cathode to the auxiliary cathode is so rapid that it cannot be re-dissolved in the
electrolyte, and once it comes against the auxiliary cathode the metal forms part
of the latter so that it cannot be attacked by the bath.
In order to collect the gas which is liberated at the anode it is sufficient to
cover the apparatus with a suitable lid or cover provided with a discharge
pipe. The apparatus is mounted on a frame or foundation of cast metal, bricks
or the like of any suitable form.
In this electrolytic apparatus the electrolyte is maintained in fusion by the heat
developed by the passage of the current. The arrangement herein before described
of the anode, the cathode and the collecting cone as well as the various arrange-

page_text: ments for refrigeration enable the central part only of the mass to be kept liquid
which ensures exceptional durability of the apparatus. The metal which is dis-
charged from the discharge pipe having been brought to a suitable temperature
by one of the systems of refrigeration herein before described may, if not very
oxidizable, be received in an ingot mould of any suitable form placed beneath
the end of the discharge pipe. If the metal is however oxidizable an ingot
mould of any suitable form is employed which is capable of being closed almost
hermetically and is provided at its upper part with an opening in which the end
of the discharge pipe can enter.
For instance for preparing sodium with this electrolytic apparatus, soda mixed
with carbonate of soda in given proportions may be taken as the electrolyte. The
pipe of the electrolising vat may be cooled by means of a cooling jacket, whilst
the collecting cone will be sufficiently refrigerated by its simple contact with the
air. As the sodium is very oxidizable, a closed ingot mould adapted to the end
of the discharge pipe is used for collecting it.
It may be explained that for preparing sodium in this electrolytic apparatus,
soda and carbonate of soda mixed in any suitable proportions are employed as
electrolyte. Various experiments made with regard to this point have shown that
it is soda carbonate which is more particularly decomposed by the passage of the
electric current, and caustic soda has as its main action to increase the conducti-
bility of the electrolyte and lower the fusing point of the soda carbonate.
According to this consideration which appears to be the correct explanation
of the phenomenon, it has been found that caustic soda may be replaced by
alkaline salts or alkaline earthy salts and carbonate of soda in solution or in
suspension in alkaline salts or alkaline earthy salts, or mixed with the soda salts
in fusion, may be employed as electrolyte, for instance a mixture of soda car-
bonate and sodium chloride may be employed as electrolyte.
It is evident that the same method may be employed for extracting potassium
it being sufficient to replace the salts having a sodium base, by salts having a
postassium base.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, as communicated to
me by my foreign correspondent, I'declare that what I claim is;-
1. The electrolytic apparatus substantially as hereinbefore described, charac-
terised essentially by the following points:-
(a) A metallic vessel having at its lower part a large pipe closed by an
insulating stopper which is traversed by the rod or conductor of the
cathode, said pipe being adapted to be cooled if required externally by
suitable means;
(b) a cathode of large surface arranged in such a way as to facilitate the
vertical rise of the globules of metal;
(c) a collecting cone intended to collect the metallic globules and to cause
the metal to pass out of the apparatus, said collecting cone being adapted
to be cooled by suitable means and having a central pipe closed by a
movable cover and provided at the side with an inclined discharge pipe (f)
and further connected to the negative conductor by means of a
resistance:
() an annular anode in one or more pieces connected by its external face
to one or more conducting supports..
2. The application of the apparatus herein before described to the extraction
by electrolytic means of all metals lighter than the electrolyte.
3. In the peculiar application of the described apparatus to the extraction of
sodium and potassium, the use as electrolyte of alkaline carbonates in suspension
or in solution in alkalis in fusion, that is to say, the use as electrolyte of mix-
tures in suitable proportions of alkaline carbonates and alkalis, as well as the

page_text: electrolysis of alkaline carbonates in suspension or in solution in alkaline salts
or in alkaline earthy salts or in a mixture of said salts in fusion, substantially as
herein before set forth.
Tlated this let dow of Val 1000
WM. P. THOMPSON & Co.,
Agents.