Process and Apparatus for the Extraction, Separation, and Refining of Metals by Electrolysis.
Year: 1892

page_text: France),
Date of Application (in United Kingdom), 21st Sept., 1892
Complete Specification Left. 21st June, 1893-Accepted, 22nd July, 1893
PROVISIONAL SPECIFICATION.
Process and Apparatus for the Extraction, Separation, and Refining
of Metals by Electrolysis.
I, DONATO TOMMASI of 3, Place Daumesnil, Paris, France, Engineer, do
hereby declare the nature of this invention to be as follows:-
My invention relates to a process and apparatus for the extraction, separation,
and refining of metals by electrolysis.
I have in another application for Letters Patent of even date herewith and
numbered 16892 described the employment of revolving cathode discs upon which
the metal is deposited in a spongy or crystalline form and removed, as fast as it
is produced, by means of brushes.
The object of the present improvement is to provide an arrangement of cathode
disc adapted for use in cases where it is desired to obtain the metallic deposit in a
compact form.
Reference is to be had to the accompanying drawings, forming part of this
Specification, in which the same letters of reference denote the same parts in all
the figures. Figure 1 represents a face view and Figure 2 an edge view of the
improved cathode disc and Figure 3 a sectional perspective view of one of the
segments of which it is composed.
The cathode disc is constituted of sector shaped segments whose edges are tongued
and slide in grooves in their supporting arms a a made of insulating and
unattackable material fixed to a hub also of insulating material keyed on the shaft.
b are the grooves in the lateral faces of the arms in which are received the tongues c
on the edges of the segments d which are held in place either by strips of insulating
material e fixed by screws or otherwise at each end to the ends of arms a or simply
by screw stops fon the lateral faces of arms a.
In order to obtain a constant contact and regular transmission of the current to
each of the segments of which the cathode disc is composed a metal strip g is
pressed against the inner ends of said segments by means of spiral or other springs h
connected to the conductive axis of the disc.
As in the previous arrangement described in my other application before referred
to, brushes or strips rub constantly against the surface of the discs, not however
for the purpose of detaching the metallic deposit but in order to produce a compact
and absolutely homogeneous deposit. It will be evident that the current required
to produce this compact deposit should be of much less intensity than for
producing a spongy or crystalline deposit..
The principal advantage of the above arrangement is that it allows of the
metallic deposit being removed in sections corresponding to each of the segments
composing the cathode disc without completely dismounting the apparatus, it being
only necessary to unscrew the covering strips or the screws as the case may be,
which may be done whether the discs are in motion or at rest, whereupon the

page_text: segment will be pressed outwards by the spring h and may thus be easily with-
drawn, either for melting or otherwise, and another seginent inserted, if a fresh
metallic deposit is required. The whole of the segments may in this manner be
removed one by one as they leave the bath. This arrangement, moreover, permits
of the removal, without entirely dismounting the apparatus, of any one of the
discs, whether in consequence of the bad quality of the metal or of insufficient or
imperfect contact or other cause, and thus effects a saving in the labor unavoidable
in other electrolytic apparatus. Another not less important advantage is that
when the apparatus is not required to work through the night or for a prolonged
period, the segments may be removed and the oxidation of the deposit thus
avoided.
When, as in the extraction of zinc, cadmium, lead, tin, antimony, etc., from their
alkaline or other solutions, it is necessary to employ an anode which is insoluble in
the electrolyte, a perforated holder of insulating material such as celluloid, ebonite,
gutta-percha, etc., is used which is filled with metallic copper, lead, silver, etc., or
other metal whose oxide is insoluble in the electrolyte and is reducible by electro-
lytic hydrogen, this metal being in a spongy or reduced state obtained by.
precipitation or other means and in the midst of which is placed a plate of carbon,
copper, or other unattackable conducting material.
This arrangement can only be employed when the electrolyte has no solvent
action upon the metal of the anode, even under the influence of the electric current,
and it has for object to enable the anode to take up the oxygen produced at the
positive pole by forming an oxide which is insoluble in the electrolyte and so
preventing the polarization of the anode and the consequent diminution of the
energy necessary for working.
When the metal has been completely oxidised, these anode holders are removed
and placed in a fresh trough containing as electrolyte acidulated or alkaline water
and connected with the negative pole so as to form cathodes, the anodes in this case
being formed either of platinized copper plates or of carbon or other unattackable
conductive substance.
Under the influence of the current, the water being decomposed, the hydrogen
reduces the oxide to the metallic state, while oxygen disengages at the positive
pole.
This method possesses the advantage, besides preventing polarization, of enabling
the same metal to be repeatedly employed as the anode, without the necessity of
renewing it after each operation.
Dated this 21st day of September 1892.
D. TOMMASI,
By A. M. & Wm. Clark,
53, Chancery Lane, London, Chartered Patent Agents.
COMPLETE SPECIFICATION.
Process and Apparatus for the Extraction, Separation, and Refining
of Metals by Electrolysis.
1, DONATO TOMMASI of 3, Place Daumesnil, Paris, France, 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 :-
My invention relates to a process and apparatus for the extraction, separation,
and refining of metals by electrolysis.
I have in another application for Letters Patent of even date herewith & numbered
16892 described the employment of revolving cathode discs upon which the metal
is deposited in a spongy or crystalline form and removed as fast as it is produced,
by means of brushes.

page_text: The object of the present improvement is to provide an arrangement of cathode
disc adapted for use in cases where it is desired to obtain the metallic deposit in a
compact form.
Reference is to be had to the drawings, left with my Provisional Specification, in
which the same letters of reference denote the same parts in all the figures. Figure 1
represents a face view and Figure 2 an edge view of the improved cathode disc
and Figure 3 a sectional perspective view of one of the segments of which it is
composed.
The cathode disc is constituted of sector shaped segments whose edges are
tongued and slide in grooves in their supporting arms a a made of insulating and
unattackable material fixed to a hub also of insulating material keyed on the shaft.
b are the grooves in the lateral faces of the arms in which are received the tongues c
on the edges of the segments d which are held in place either by strips of insulating
material e fixed by screws or otherwise at each end to the ends of arms a or simply
by screw stops f on the lateral faces of arms a.
In order to obtain a constant contact and regular transmission of the current to
each of the segments of which the cathode disc is composed a metal strip g is
pressed against the inner ends of said segments by means of spiral or other springs
connected to the conductive axis of the disc.
h
As in the arrangement described in my other application before referred to,
brushes or strips rub constantly against the surface of the disc, not however for the
purpose of detaching the metallic deposit but in order to produce a compact and
absolutely homogeneous deposit. It will be evident that the current required to
produce this compact deposit should be of much less intensity than for producing a
spongy or crystalline deposit.
The principal advantage of the above arrangement is that it allows of the
metallic deposit being removed in sections corresponding to each of the segments
composing the cathode disc without completely dismounting the apparatus, it being
only necessary to unscrew the covering strips e or the screws f as the case may be,
which may
be done whether the discs are in motion or at rest, whereupon the
segment will be pressed outwards by the spring h and may thus be easily with-
drawn, either for melting or otherwise, and another segment inserted, if a fresh
metallic deposit is required. The whole of the segments may in this manner be
removed one by one as they leave the bath. This arrangement, moreover, permits
of the removal, without entirely dismounting the apparatus, of any one of the discs,
whether in consequence of the bad quality of the metal or of insufficient or
imperfect contact or other cause, and thus effects a saving in the labor unavoidable
in other electrolytic apparatus. Another not less important advantage is that
when the apparatus is not required to work through the night or for a prolonged
period, the segments may be removed and the oxidation of the deposit thus avoided.
When, as in the extraction of zinc, cadmium, lead, tin, antimony, etc., from their
alkaline or other solutions, it is necessary to employ an anode which is insoluble in
the electrolyte, a perforated holder of insulating material such as celluoid, ebonite,
gutta-percha, etc., is used which is filled with metallic copper, lead, silver, etc., or
other metal whose oxide is insoluble in the electrolyte and is reducible by
electrolytic hydrogen, this metal being in a spongy or reduced state obtained by
precipitation or other means and in the midst of which is placed a plate of carbon,
copper, or other unattackable conducting material.
This arrangement can only be employed when the electrolyte has no solvent
action upon the metal of the anode, even under the influence of the electric current,
and it has for object to enable the anode to take up the oxygen produced at the
positive pole by forming au oxide which is insoluble in the electrolyte and so
preventing the polarization of the anode and the consequent diminution of the
energy necessary for working.
When the metal has been completely oxidised, these anode holders are removed
and placed in a fresh trough containing as electrolyte acidulated or alkaline water
and connected with the negative pole so as to no longer form anodes but cathodes,

page_text: the anodes in this case being formed either of platinized copper plates or of carbon
or other unattackable conductive subtance.
Under the influence of the current, the water being decomposed, the hydrogen
reduces the oxide to the metallic state, while oxygen disengages at the positive
pole.
This method possesses the advantage, besides preventing polarization, of enabling
the same metal to be repeatedly employed as the anode, without the necessity of
renewing it after each operation.
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:
1st. In an electrolytic apparatus of the kind herein specified, the construction of
rotary cathode discs, for receiving a compact metallic deposit, of sector-shaped
pieces so fitted in a holder frame as to be in electric contact and capable of
independent removal and replacement, as described.
2nd. In the electrolytic process herein described and particularly for the extrac-
tion of metals from their alkaline or other solutions, the employment as an anode of
a metal whose oxide is insoluble in the electrolyte and is reducible by hydrogen,
the metal being in a divided state and contained in a perforated holder, as specified.
Dated this 21st day of June 1893.
D. TOMMASI,
By A. M. & Wm. Clark,
53, Chancery Lane, London, Chartered Patent Agents.