Improvements in Method of and Apparatus for Separating Metals.
Year: 1895

page_text: Date of Application, 8th Jan., 1895-Accepted, 23rd Feb., 1895
COMPLETE SPECIFICATION.
Improvements in Method of and Apparatus for Separating
Metals.
1, BERNARD MOEBIUS, of 133 East 18th Street, in the City, County and State
of New York, United States of America, Mining 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 an improved method and apparatus for separating
metals by electrolysis, its principal object being to withdraw the silver or other
deposited metal from the apparatus as fast as it is deposited and to prevent short.
circuiting caused by the formation of bridges between the anodes and cathodes.
For this purpose my invention consists essentially in passing the cathode through
the bath in close proximity to the anode or anodes, depositing the silver on the
cathode in a loose, spongy or crystalline form, collecting the silver carried off by
the cathode and discharging it continuously outside of the bath and preventing the
anions and cations from being mixed with each other.
In carrying out my invention 1 use by preference apparatus of the nature shown
in the annexed drawings, in which :-
Fig. 1 is a sectional elevation of the apparatus, part being broken away.
Fig. 2 is a vertical cross section on the line x-y, Fig. 1.
Fig. 3 is a detail view of the contact lever for the anodes.
Fig. 4 is a detail view showing modified forms for the diaphragm and frame.
Referring to the drawings the letter A represents a tank of the usual construction
for the electrolytic bath. B B' are rolls placed within the tank, one of which,
B, is rotated in the direction of the arrow by suitable means, such as the pulley P.
C is an endless apron stretched between the rolls B and B and supported by
intermediate rolls and 6'. This endless apron is the cathode and is for this
purpose formed entirely of sheet metal, by preference silver; or it may be made of
sheet metal with a non-metallic backing, or of non-metallic material upon one side
of which a coating of silver is deposited by electrolysis aud firmly compressed
during the process of deposition, or copper may first be deposited and then coated
with silver.
As seen in the drawings, the entire endless cathode is contained within the bath
and is stretched horizontally.
EE are frames and G anode plates supported by said frames E. The bottom
of the frames consists of diaphragms of muslin or other suitable material such
as porous earthenware; or the whole frame together with the bottom may be a
dish of porous earthenware, as shown in Fig. 4 where E' G' is the porous dish.
The frames E are removably supported upon the sides of the tank A.
D is an endless apron or conveyor formed of rubber cloth, canvas or other
suitable material; it is stretched between rolls d and d', the roll d being rotated
in the direction of the arrow by suitable means, such as the chain n and wheels K
and O.
K is a conductor supplied with positive current from a dynamo machine and
connected with the anodes G (formed of the bullion to be separated) by contact
arms M. L is the conductor for the negative current connected with the movable
cathode C by brushes F. The contact arms M are by preference made of copper
and the ends protected by rubber sleeves r and thin platinum caps p, as shown in
Fig. 3.

page_text: S is a scraper bearing against the lower part of the apron D, and Ra
receptacle into which the silver or other deposit is discharged. The receptacle R
is provided with a strainer for filtering off the liquid carried over with the
deposit.
The bullion to be separated is cast into anode plates G, which are placed
into the frames E so as to be immersed in the exciting liquid and the anions and
cations are thus separated by the diaphragms and prevented from being mixed.
As an exciting liquid I use by preference a strong solution of sodium or potassium
nitrate sufficiently acidulated with nitric and sulphuric acid to keep some silver
and all the copper in solution, such a bath being a very good conductor of
electricity.
When parting bullion containing silver, gold, copper and other metals, a current
of small electromotive force is used and the dissolved silver is precipitated upon the
cathode C in a loose spongy state or in crystalline form; it is slowly carried by
the cathode C over the roll B and either collected in the tank near its end, whence
it may be removed, or by preference collected upon a conveyor D, which at once
takes it out of the tank and discharges it into the receptacle R whence it is taken
to the melting pot.
The copper is dissolved but remains in solution provided the exciting liquid be
properly acidulated and not too poor in silver and too rich in copper.
By slowly moving the cathode past the anodes, collecting the deposit therefrom
and again presenting fresh surfaces of the cathode to the anodes, short circuiting
such as generally caused by bridges formed between the anodes and cathodes, is
prevented. The cathode may pass very close to the anodes, thus reducing
resistance; the crystals deposited upon the cathode form part of the same, increase
the surface and likewise reduce resistance. The work goes on continuously without
interruption for cleaning; the silver is delivered ready for the melting pot instead
of being blocked up in the apparatus and requiring the investment of large
capital. The apparatus is very simple and requires but little repair and attention.
The gold and the platinum metals are retained upon the diaphragms together
with lead peroxide, some peroxide of silver and other impurities. Whenever any
one of the anode plates is exhausted, its contact lever is raised up and a fresh anode
plate put in. The residue upon the diaphragms is collected in rotation, so that
there is no interruption in the process. This residue, containing gold and other
metals, is treated in the usual well known manner.
By the method and apparatus described the entire anode is subjected to the
action of the current and no scraps are left which have to be remelted, as in other
processes.
While the method and apparatus above described are designed particularly
for separating alloys containing silver, they may be used for other purposes, as,
for instance, for the electrolytic deposition of copper in a loose spongy state.
By arranging a series of vats in tiers one above the other and discharging all
the silver into one and the same receptacle, a great economy in space may be
effected.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I déclare that what I
claim is :
1. The herein described method of refining alloys containing silver, which
consists in placing the alloys as anodes into a bath suitable for dissolving silver
and copper therefrom, subjecting the anodes to an electric current of small electro-
motive force, slowly passing a silver cathode through the bath beneath the anodes
and in close proximity to the same, preventing the mixing of anions and cations,
depositing the silver upon the cathode in a loose, spongy or crystalline form, and
collecting the silver deposited on the cathode, substantially as specified.
2. The herein described method of refining alloys containing silver, which
consists in placing the alloys as anodes into a bath suitable for dissolving silver and

page_text: copper therefrom, subjecting the anodes to an electric current of small electro-
motive force, slowly passing a silver cathode through the bath beneath the anodes
and in close proximity to the same, preventing the mixing of anions and cations,
depositing the silver in a loose, spongy or crystalline form upon the cathode, and
continuously carrying the same out of the bath by mechanical means, substantially
as specified.
3. The herein described method of refining alloys containing silver, which consists
in placing the anodes into a bath of nitrates sufficiently acidulated to keep the
copper in solution, subjecting the anodes to an electric current of small electro-
motive force, slowly passing a cathode through the bath beneath the anodes and in
close proximity to the same, preventing the mixing of anions and cations, depositing
the silver upon the cathode in a loose, spongy or crystalline form, leaving the gold,
platinum metals and impurities at the anodes, collecting the silver from the cathode
and discharging it, substantially as specified.
4. The herein described method of refining alloys containing silver, consisting in
subjecting the alloy as anode to an electric current of small electromotive force in
a bath of an alkali nitrate, such as sodium nitrate, sufficiently acidulated with
nitric acid and sulphuric acid to keep the copper in solution, passing a cathode of
silver through the bath beneath the anodes and in close proximity to the same,
depositing the silver upon the cathode in a loose, spongy or crystalline form,
collecting it and carrying it out of the bath, and preventing the mixing of the
anions and cations, substantially as specified.
5. In an electrolytic apparatus for the separation of metals, the combination of
an anode formed of the metals to be separated, a horizontal endless cathode in
the form of an endless apron, diaphragm frames suitable for receiving and sub-
merging anode plates placed horizontally in close proximity to the upper part
of the endless cathode and adapted to prevent the mixing of anions and cations,
and mechanical means for collecting the deposit from the endless cathode,
substantially as described.
6. An electrolytic apparatus consisting of the vat A, anode frames E with
diaphragms, endless cathode C stretched on rolls, means for slowly moving the
endless cathode beneath the anodes and in close proximity to the same, proper
electric connection for the anodes and the cathode and a conveyor adapted to
collect the deposit from the endless cathode within the bath and to deliver it
outside the bath, substantially as specified.
Dated this 8th day of January 1805
HARRIS & MILLS,
23, Southampton Buildings, London, W.C., Agents.