A NEW AND IMPROVED PROCESS AND APPARATUS FOR THE EXTRACTION OP METALS FROM THEIR CHLORIDES OR FLUORIDES
Year: 1884

page_text: [Communicated from abroad by Richard Grätzel, of Hanover, in the Germ
Padove
1. LORENTZ ALBERT GROTH, K.G.V. Civil Engineer and Managing Director of
the Universal Inventors and Patentees Financial Company Limited, 30 Finsbury
Pavement Loudon E.C. in the County of Middlesex, do hereby declare the nature
of said invention for A NEW AND IMPROVED PROCESS AND APPARATUS FOR THE
EXTRACTION OP METALS FROM THEIR CHLORIDES OR FLUORIDES a communication
to me from abroad by R. Graetzel of Hanover in the German Empire to be as
follows:-
The object of this invention is the extraction of metals especially of aluminium
and magnesium from their combinations with chlorine and fluorine on a large scale
by means of electrolysis with the assistance of a gas having reducing qualities or
which is neutral in respect to the said metals. It consists partly in thus insulating
the electrodes that the chlorine formed at the positive electrode may be conducted
away separate from the gas and partly in continuously regenerating the molten
mass under treatment.
A dynamo-machine is used for supplying the electricity.
According to the strength of the machine two or more melting vessels which also
serve as decomposition vessels may be placed behind or at the side one of ther each
in a separate hearth.
They are made of metal, copper, iron, or steel and form the negative electrode.
They are placed on a fire-brick-plate in the centre of the grate and the top opening
of the hearth is then closed with a fire-brick-cover.
Each vessel is closed with a cover.
The reducing or neutral gas is led by a pipe to the melting vessel and out again
through another pipe.
The positive carbon electrode is placed within a separate china or other refractory
non-conducting vessel in order to insulate both electrodes and to keep the chlorine
formed on the carbon and the neutral gas separate.

page_text: This insulating-vessel preferably of cylindrical shape is hung up within the
outer, or smelting vessel through a hole in the lid and has itself a covering through
which the carbon projects.
At the bottom or on the sides at the lower end are holes through which the
molten matter is admitted to the carbon electrode.
The chlorine when formed is led away through a pipe common for all the
hearths.
The connection of two or more melting vessels in one circuit is effected in the
usual way.
For producing aluminium which usually adheres to the negative electrode or
settles as powder on the bottom of the melting vessel it is best to make the negative
electrode of metal preferably of aluminium.
The melting vessel proper may in such case be made of porcelain clay or other
like refractory material and protected by an outer metal casing from direct contact
with the flames.
Into this vessel the metal or aluminium electrode is inserted and placed in
connection with the negative pole of the dynamo-machine.
If the melting-vessel is made of graphite the outer metal casing can however be
dispensed with. Moreover the metalic electrode may be placed directly into a metal
vessel which is able to resist the heat employed.
For renewing or regenerating in the molten mass the chloride or fluoride
decomposed by the process and simultaneously allowing the tension of the electric
current within the apparatus to be reduced plates or rods made of alumina and
carbon for aluminium and of magnesia and carbon for magnesium are placed in the
inner or insulating vessel near the positive carbon electrode.
The carbon enters into combination with the oxygen of the metalic oxide while
the metal combines with the chlorine and is melted.
Dated this 3rd day of January 1884
LORENTZ ALBERT GROTH.

page_text: I, LORENTZ ALBERT GROTH K.G.V. Civil Engineer and Managing Director of
the Universal Inventors and Patentees Financial Company, Limited, 30 Finsbury
Pavement London E.C. in the County of Middlesex do hereby declare the nature
of said invention for "A NEW AND IMPROVED PROCESS AND APPARATUS FOR THE
EXTRACTION OF METALS FROM THEIR CHLORIDES OR FLUORIDES a communication
to me from abroad. by R. Graetzel of Hanover in the German Empire, and in
what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :—
"
The object of this invention is the extraction of certain metals, such as
aluminium and magnesium from their combinations with chlorine and fluorine on
a large scale by means of electrolysis with the assistance of a gas having reducing
qualities or which is neutral in respect to the said metals, and the improvements
consist in means, firstly, for efficiently insulating from each other the positive and
the negative electrodes, and, secondly, for regenerating in the molten mass the
chloride or fluoride decomposed during the process, and simultaneously allowing
the process to be carried out by an electric current of less tension.
On the annexed sheet of drawings Fig. I represents in vertical section, together
with its furnace, an apparatus in which the negative electrode is constituted by
the melting pot; Fig. 2 is a like section of an apparatus with negative electrode
separate from the pot. Fig. 3 is an outside view of the tube or vessel y serving as
insulator.
In
In the process for extracting the metals of alkaline earths from their chlorides
and fluorides by electrolysis, as hitherto practiced by the inventor and partly
described in the specification of the British letters patent A.D. 1882 No. 5509, an
apparatus is used in which the negative electrode is either formed by the melting
and decomposing-vessei itself, which is in this case made of metal, or by a separate
metallic surface, such as a dish or plate of metal, or metallic strips or wires.
the latter case the melting pot may be lined with porcelain, fire-clay, plumbago or
other suitable fire-proof material. An apparatus of the first kind is shown by
Fig. 1, and one of the second kind by Fig. 2. In Fig. 1 the conducting-wire n
connects the vessel a, and in Fig. 2 the separate electrode 7, with the negative pole
of the dynamo-machine. In both apparatuses is the positive electrode, made of
carbon, and m the wire leading from the same to the positive pole of the said
machine.
.
It has moreover been set forth in the aforesaid specification that a gas having
reductive qualities, as for instance lighting-gas, may be introduced into the melting-
vessel. In Figs. 1 and 2, b is the pipe for the admission of the said gas, and c the
pipe for the egress of air at the commencement of the operation, and through
which gas may be allowed to escape during its continuation. The purpose of the
employment of such gas is to prevent the metal separated out by the process from
being oxidised by the air. Instead of a reductive gas, a gas which is neutral in
respect to the metal, as for instance hydrogen, may also be used with like effect.
The process may, however, also be carried out without the aid of such gas, and in
this case the decomposing-vessel should be well closed, so as to prevent fresh air
from entering.
If, in the melting and decomposing-apparatus thus described, there is an
uninterrupted body or mass of air or gas between the upper portions of the two
electrodes, the decomposing operation does not proceed satisfactorily. The quantity

page_text: of metal separated out is insufficient and the apparatus works irregularly. This
arises from the circumstance that the air or gas when being hot, is a conductor of
electricity, and consequently leads a considerable part of the current from one
Likewise the
electrode to the other, so as to divert it from its required course.
slags forming on the surface of the molten mass are a conductive substance. In
order to prevent the formation of shunt-currents through these mediums and to
conduct the whole current through the mass to be acted upon, the inventor arranges
within the melting-pot a partition of a non-conductive material adapted to insulate
the two electrodes from each other upon their parts exposed to contact with the
hot air or gas and the slags. This partition or insulator consists in the tube or
vessel g of cylindrical or other suitable form, open at its lower end, or provided at
or near its bottom with apertures gl, and closed at the top, and which is made of
porcelain or other material being a non-conductor of electricity and adapted to
resist the action of chlorine or fluorine set free during the decomposing-process and
of the heat to which it is exposed. The said insulator is inserted through the top
or lide of the melting-vessel and arranged to extend so far down into the latter as
to be with its open end, or with the apertures gl below the surface of the molten
mass to be decomposed, and through it is passed into the said mass the positive
electrode k.
For
In addition to its described effect the insulator, when thus arranged with the
positive electrode in it, operates to keep the chlorine or fluorine, evolved on the
electrode, separate from the gas which may be employed in the process.
conducting away the chlorine or fluorine a pipe p is put in communication with
the top of the insulator.
In case lighting-gas is introduced by the aforesaid pipe b, the insulator is of
special importance, inasmuch as by the action of the chlorine or fluorine this gas is
decomposed into hydro-chloric or hydro-fluoric acid and carbon, the latter forming
on the surface of the molten mass a highly conductive layer.
For renewing or regenerating in the molten mass the chloride or fluoride
decomposed by the process, and for simultaneously allowing the process to be
carried out by an electric current of less tension, the inventor places into the
insulator g, close to the positive electrode, rods or plates d, or pieces of other
suitable form, composed of the oxide of the same metal as that which is to he
Thus for aluminium they
extracted from the molten compound, and of carbon.
are made of alumina and carbon, and for magnesium of maguesia and carbon.
These rods, &c., will be acted upon by the nascent chlorine or fluorine; the metal
of the oxide combines with the said halogene or a portion thereof, and passes as
chloride or fluoride into the molten mass, while the carbon combines with the
oxygen of the metallic oxide to carbonic oxide. In this manner chloride or fluoride
is restored to the fused material which is thus continuously regenerated either partly
or completely. The said rods or pieces d may therefore be called regenerating-
pieces. The portion of chlorine or fluorine not combining with the metal of the
oxide, passes off together with the carbonic oxide by the pipe p.
On account of the chemical affinity of the chlorine or fluorine to the metal in the
regenerating-pieces, the separation of the former from the chloride or fluoride in
fusion is facilitated, inasmuch as the electric energy is supported in its operation
by chemical energy. The decomposition may therefore be carried out by a current
of less tension.
but they
By preference
The regenerating-pieces being placed close to the said positive electrode, will be
within the electric circuit upon their part immersed in the fused mass;
are not intended to be directly connected with the conductor m.
the said pieces are composed of such relative quantities of the metallic oxide and
powdered charcoal as that, by the combination of the latter with the oxygen of the
former, carbonic oxide will be produced. A slight excess of charcoal is, however,
of advantage. The ingredients are made up with some tar or a solution of dextrine
into a dough, which is pressed into moulds, whereupon the pieces thus obtained
are dried and exposed to a red beat in a closed receptacle.

page_text: Having thus particularly described and ascertained the nature of this invention,
and the manner in which it is to be performed as communicated to me by my
correspondent, I declare that what I claim is :
1. In combination with a metallic-melting and decomposing-pot a, and means
for conducting an electric current into the substance contained therein, the
insulator consisting of a non-conductor of electricity and communicating at its
bottom end with the said pot, and through which the positive electrode is passed
into the substance, substantially as and for the purpose described.
2. In the process of extracting a metal such as aluminium and magnesium from
a chloric or fluoric compound thereof by an apparatus comprising a metallic melting-
pot, means for conducting an electric current into the compound contained in the
pot, and an insulator consisting of a nou-conductor of electricity and through
which the positive electrode is passed, the employment of regenerating-pieces d,
composed of the same metal as that which is to be extracted and of carbon, and
which are placed into the said insulator, substantially as and for the purpose set
forth.
Dated this 2nd
T

page_text: PROVISIONAL SPECIFICATION.
I, LORENTZ ALBERT GROTH, K.G.V. Civil Engineer and Managing Director of
the Universal Inventors and Patentees Financial Company Limited, 30 Finsbury
Pavement London E.C. in the County of Middlesex, do hereby declare the nature
of said invention for A NEW AND IMPROVED PROCESS AND, APPARATUS FOR THE
EXTRACTION OF METALS FROM THEIR CHLORIDES OR FLUORIDES a communication
to me from abroad by R. Graetzel of Hanover in the German Empire to be as
follows:-
The object of this invention is the extraction of metals especially of aluminium
and magnesium from their combinations with chlorine and fluorine on a large scale
by means of electrolysis with the assistance of a gas having reducing qualities or
which is neutral in respect to the said metals. It consists partly in thus insulating
the electrodes that the chlorine formed at the positive electrode may be conducted
away separate from the gas and partly in continuously regenerating the molten
mass under treatment.
A dynamo-machine is used for supplying the electricity.
According to the strength of the machine two or more melting vessels which also
serve as decomposition vessels may be placed behind or at the side one of ther each
in a separate hearth.
They are made of metal, copper, iron, or steel and form the negative electrode.
They are placed on a fire-brick-plate in the centre of the grate and the top opening
of the hearth is then closed with a fire-brick-cover.
Each vessel is closed with a cover.
The reducing or neutral gas is led by a pipe to the melting vessel and out again
through another pipe.
The positive carbon electrode is placed within a separate china or other refractory
non-conducting vessel in order to insulate both electrodes and to keep the chlorine
formed on the carbon and the neutral gas separate.
D

page_text: This insulating-vessel preferably of cylindrical shape is hung up within the
outer, or smelting vessel through a hole in the lid and has itself a covering through
which the carbon projects.
At the bottom or on the sides at the lower end are holes through which the
molten matter is admitted to the carbon electrode.
The chlorine when formed is led away through a pipe common for all the
hearths.
The connection of two or more melting vessels in one circuit is effected in the
usual way.
For producing aluminium which usually adheres to the negative electrode or
settles as powder on the bottom of the melting vessel it is best to make the negative
electrode of metal preferably of aluminium.
The melting vessel proper may in such case be made of porcelain clay or other
like refractory material and protected by an outer metal casing from direct contact
with the flames.
Into this vessel the metal or aluminium electrode is inserted and placed in
connection with the negative pole of the dynamo-machine.
If the melting-vessel is made of graphite the outer metal casing can however be
dispensed with. Moreover the metalic electrode may be placed directly into a metal
vessel which is able to resist the beat employed.
For renewing or regenerating in the molten mass the chloride or fluoride
decomposed by the process and simultaneously allowing the tension of the electric
current within the apparatus to be reduced plates or rods made of alumina and
carbon for aluminium and of magnesia and carbon for magnesium are placed in the
inner or insulating vessel near the positive carbon electrode.
The carbon enters into combination with the oxygen of the metalic oxide while
the metal combines with the chlorine and is melted.
Dated this 3rd day of January 1884.

page_text: 41
I, LORENTZ ALBERT GROTH K.G.V. Civil Engineer and Managing Director of
the Universal Inventors and Patentees Financial Company, Limited, 30 Finsbury
Pavement London E.C. in the County of Middlesex do hereby declare the nature
of said Invention for A NEW AND IMPROVED PROCESS AND APPARATUS FOR THE
EXTRACTION OF METALS FROM THEIR CHLORIDES OR FLUORIDES," a communication
to me from abroad by R. Graetzel of Hanover in the German Empire, and in
what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
The object of this invention is the extraction of certain metals, such as
aluminium and magnesium from their combinations with chlorine and fluorine on
a large scale by means of electrolysis with the assistance of a gas having reducing
qualities or which is neutral in respect to the said metals, and the improvements
consist in means, firstly, for efficiently insulating from each other the positive and
the negative electrodes, and, secondly, for regenerating in the molten mass the
chloride or fluoride decomposed during the process, and simultaneously allowing
the process to be carried out by an electric current of less tension.
On the annexed sheet of drawings Fig. 1 represents in vertical section, together
with its furnace, an apparatus in which the negative electrode is constituted by
the melting pot; Fig. 2 is a like section of an apparatus with negative electrode
separate from the pot. Fig. 3 is an outside view of the tube or vessel g serving as
insulator.
In the process for extracting the metals of alkaline earths from their chlorides
and fluorides by electrolysis, as hitherto practiced by the inventor and partly
described in the specification of the British letters patent A.D. 1882 No. 5509, an
apparatus is used in which the negative electrode is either formed by the melting
and decomposing-vessel itself, which is in this case made of metal, or by a separate
metallic surface, such as a dish or plate of metal, or metallic strips or wires. In
the latter case the melting pot may be lined with porcelain, fire-clay, plumbago or
other suitable fire-proof material. An apparatus of the first kind is shown by
Fig. 1, and one of the second kind by Fig. 2. In Fig. 1 the conducting-wire n
connects the vessel a, and in Fig. 2 the separate electrode r, with the negative pole
of the dynamo-machine. In both apparatuses is the positive electrode, made of
carbon, and m the wire leading from the same to the positive pole of the said
machine.
It has moreover been set forth in the aforesaid specification that a gas having
reductive qualities, as for instance lighting-gas, may be introduced into the melting-
vessel. In Figs. 1 and 2, b is the pipe for the admission of the said gas, and c the
pipe for the egress of air at the commencement of the operation, and through
which gas may be allowed to escape during its continuation. The purpose of the
employment of such gas is to prevent the metal separated out by the process from
being oxidized by the air. Instead of a reductive gas, a gas which is neutral in
respect to the metal, as for instance hydrogen, may also be used with like effect.
The process may, however, also be carried out without the aid of such gas, and in
this case the decomposing-vessel should be well closed, so as to prevent fresh air
from entering.
If, in the melting and decomposing-apparatus thus described, there is an
uninterrupted body or mass of air or gas between the upper portions of the two
electrodes, the decomposing operation does not proceed satisfactorily. The quantity

page_text: of metal separated out is insufficient and the apparatus works irregularly. This
arises from the circumstance that the air or gas when being hot, is a conductor of
electricity, and consequently leads a considerable part of the current from one
electrode to the other, so as to divert it from its required course. Likewise the
slags forming on the surface of the molten mass are a conductive substance. In
order to prevent the formation of shunt-currents through these mediums and to
conduct the whole current through the mass to be acted upon, the inventor arranges
within the melting-pot a partition of a non-conductive material adapted to insulate
the two electrodes from each other upon their parts exposed to contact with the
hot air or gas and the slags. This partition or insulator consists in the tube or
vessel g of cylindrical or other suitable form, open at its lower end, or provided at
or near its bottom with apertures g¹, and closed at the top, and which is made of
porcelain or other material being a non-conductor of electricity and adapted to
resist the action of chlorine or fluorine set free during the decomposing-process and
of the heat to which it is exposed. The said insulator is inserted through the top
or lide of the melting-vessel and arranged to extend so far down into the latter as
to be with its open end, or with the apertures g¹ below the surface of the molten
mass to be decomposed, and through it is passed into the said mass the positive
electrode k.
In addition to its described effect the insulator, when thus arranged with the
positive electrode in it, operates to keep the chlorine or fluorine, evolved on the
electrode, separate from the gas which may be employed in the process. For
conducting away the chlorine or fluorine a pipe p is put in communication with
the top of the insulator.
In case lighting-gas is introduced by the aforesaid pipe b, the insulator is of
special importance, inasmuch as by the action of the chlorine or fluorine this gas is
decomposed into hydro-chloric or hydro-fluoric acid and carbon, the latter forming
on the surface of the molten mass a highly conductive layer.
For renewing or regenerating in the molten mass the chloride or fluoride
decomposed by the process, and for simultaneously allowing the process to be
carried out by an electric current of less tension, the inventor places into the
insulator g, close to the positive electrode, rods or plates d, or pieces of other
suitable form, composed of the oxide of the same metal as that which is to be
extracted from the molten compound, and of carbon. Thus for aluminium they
are made of alumina and carbon, and for magnesium of magnesia and carbon.
These rods, &c., will be acted upon by the nascent chlorine or fluorine; the metal
of the oxide combines with the said halogene or a portion thereof, and passes as
chloride or fluoride into the molten mass, while the carbon combines with the
oxygen of the metallic oxide to carbonic oxide. In this manner chloride or fluoride
is restored to the fused material which is thus continously regenerated either partly
or completely. The said rods or pieces d may therefore be called regenerating-
pieces. The portion of chlorine or fluorine not combining with the metal of the
oxide, passes off together with the carbonic oxide by the pipe p.
On account of the chemical affinity of the chlorine or fluorine to the metal in the
regenerating-picces, the separation of the former from the chloride or fluoride in
fusion is facilitated, inasmuch as the electric energy is supported in its operation
by chemical energy. The decomposition may therefore be carried out by a current
of less tension.
The regenerating-pieces being placed close to the said positive electrode, will be
within the electric circuit upon their part immersed in the fused mass; but they
are not intended to be directly connected with the conductor m. By preference
the said pieces are composed of such relative quantities of the metallic oxide and
powdered charcoal as that, by the combination of the latter with the oxygen of the
former, carbonic oxide will be produced. A slight excess of charcoal is, however,
of advantage. The ingredients are made up with some tar or a solution of dextrine 5
into a dough, which is pressed into moulds, whereupon the pieces thus obtained
are dried and exposed to a red heat in a closed receptacle.

page_text: Having thus particularly described and ascertained the nature of this invention,
and the manner in which it is to be performed as communicated to me by my
correspondent, I declare that what I claim is :
1. In combination with a metallic-melting and decomposing-pot a, and means
for conducting an electric current into the substance contained therein, the
insulator g consisting of a non-conductor of electricity and communicating at its
bottom end with the said pot, and through which the positive electrode is passed
into the substance, substantially as and for the purpose described.
2. In the process of extracting a metal such as aluminium and magnesium from
a chloric or fluoric compound thereof by an apparatus comprising a metallic melting-
pot, means for conducting an electric current into the compound contained in the
pot, and an insulator g consisting of a non-conductor of electricity and through
which the positive electrode is passed, the employment of regenerating-pieces d,
composed of the same metal. as that which is to be extracted and of carbon, and
which are placed into the said insulator, substantially as and for the purpose set
forth.
1
.