Improvements relating to the Separation and Refining of Metals and to Apparatus therefor.
Year: 1888

page_text: Date of Application, 11th Feb., 1888
Specification Accepted, 16th Mar., 1888
Improvements relating to the Separation and Refining of Metals and
to Apparatus therefor.
I, HENRY HARRIS LAKE, of the firm of Haseltine, Lake & Co., Patent Agents,
Southampton Buildings, in the County of Middlesex 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 object of this improvement is to facilitate the separation of precious metals
from baser metals and also the separation from metals generally of such foreign
matters as may be incorporated with them.
The invention consists in a process of treating metal, consisting in rolling the
metal into platos, in arranging such plates in an electrolytic bath between an anode
plate and a cathode plate without any connection between the plates to be treated or any
of the plates to be treated and the anode plate or cathode plate except through an
electrolytic solution, and in subjecting the plates to the action of a current of electricity.
The plates to be treated will be most advantageously supported above the bottom of
the bath so that the lower edges of the portions subjected to electrolytic action, will
have nothing immediately below them.
The solution of the bath will preferably be gently circulated from the upper to the
lower portion of the bath.
The invention also consists in a bath having side pieces provided with vertically
extending grooves, closed at the extreme lower ends. The ends of the grooves may
be closed by means of plugs driven into them. However, the grooves shall bo closed
at the lower ends, the material closing them or extending across them will preferably
not project horizontally beyond the sides of the grooves. The sides of the bath having
the grooves may be made separate from the bath and may be driven on to the side
edges of the plates.
The invention also consists in the combination of a number of electrolytic baths, a
receptacle or reservoir for containing the electrolytic solution, a pump for conveying
the solution from the receptacle to the electrolytic baths, a pipe extending from the
receptacle or reservoir, a conduit extending adjacent to the baths and communicating
with the said receptacle or reservoir, branch pipes extending-from the pipe. aforesaid

page_text: to the baths, cocks for curtailing the passage of the electrolytic solution from the
branch pipes, and outlets for conveying the solution from the several baths to the
said conduit.
The invention further consists of the combination with an electrolytic bath, of a
siphon communicating with the bath, a trough into which the siphon may discharge,
the siphon being provided with a hole in the upper part of that one of its limbs which
is within the bath so that whenever the electrolytic solution in the bath shall rise
sufficiently high to cover such hole, it will render the siphon operative and so that
when the solution shall be drawn off sufficiently high to cover such hole, it will render
the siphon operative, and so that when the solution shall be drawn off sufficiently to
expose the said hole, the operation of the siphon will be stopped.
The accompanying drawing illustrates an apparatus adapted for use in carrying out
my improvement. Figure 1, is a sectional side view of electrolytic baths or tanks
embodying my improvement, arranged in series, and a dynamo electric machine
connected therewith, together with certain appurtenances of the baths. Figure 2, is a
plan or top view of the same. Figure 3, is a transverse vertical section of the apparatus
taken at the plane of the dotted line xx, Figure 2 and looking in the direction
indicated by the arrows extending from the ends of said dotted line. Figure 4, is a
horizontal section of a part of one of the baths which form parts of the apparatus.
Figure 5 is a transverse vertical section of one of the baths which form parts of the
apparatus. Figure 6 is a perspective view of one of a number of side pieces which
are employed in each of the baths of the apparatus for the purpose of receiving the
side edges of the plates to be treated and supporting such plates above the bottom of
the bath. Similar letters of reference designate corresponding parts in all the
figures.
-
A designates a dynamo electric machine which may be of any approved style
suitablo for electro-plating. I have deemed it sufficient to give but an arbitrary
representation of this machine, but I have marked the wires connected to the
machino and
so that the representation will be perfectly intelligible. The
positive pole is connected by a wire B with the anode plate C of electrolytic baths or
tanks T. I have shown two of these baths T arranged side by side and have repre-
sented the wire B as branching so as to extend to the anode platos C of both of these
baths.
The cathode plates D of these baths are connected by wires or rods E with the
anode plates C¹ of other electrolytic baths or tanks T'.
There are two of the baths T and they are shown as arranged side by side and in
line with the baths T.
There may be a different number of baths used, but I have illustrated a sufficient
number to enable me to explain all that will be nocessary for an understanding of my
improvement. Should a greater number be used, they may be connected to the.
baths T¹ in the same manner that the baths T are connected to the baths T¹. The
last baths of the series, in the present instance, the baths T' have their cathode
plates D' connected to a wire B which extends to the negative pole of the dynamo
olectric machine.
The anode and cathole plates of each bath are arranged as far apart as possible and
consequently close to the ends of the bath. Between them are arranged a number of
plates G of the metal which is to be treated for the purpose of refining it or
separating its constituent parts. The anode plate of each bath will generally be of
the same character as tho plates G of the metal to be treated.
Assuming that the anode plate of each bath is of copper combined with a greater
or less percentage of precious metals and other foreign matter, and that the plates G.
to be treated are the same, the solution in the bath will be a copper solution, as for
instance a sulphate of copper solution. The cathode platos may then be made of any
suitable material. Indeed they may also be of copper.
The plates of the metal to be treated may be cast in shape to be used in the baths;
but it will be preferable to subject the plates of metal which are to be treated according
to my improvement, to a rolling operation for the purpose of compacting them and

page_text: rendoring them homogeneous. The rolling will be done before they are placed in the
baths. They will be arranged as close together in the baths as they can be located
without danger of contact and supported so as to be elevated slightly above the bottom
of the baths. The means whereby they are supported in the present example of my
improvement consist of grooves a in the side pieces of the baths; such grooves being
closed at the bottom so that they may not only sustain the plates sidewise, but
vertically, by extending under the bottom of the lateral edge portions. When the
platos are supported in this manner, their main portions which extend across the baths
between the grooves a and which are subject to electrolytic action, will not rest upon
anything beneath them.
Preferably the grooves a are made in strips of wood which are independent of or
mado separate from the side walls of the baths; and these strips of wood may perhaps
inost advantageously have the grooves closed at the lower ends by driving plugs into
the grooves at the lower ends. A strip or strips extending beneath the grooves could
however be used. One of the grooved strips of wood is shown in Fig. 6; a¹ being
a plug which is made separately from the strip and driven into the groove of the strip
at the lower end of the strip. It will be observed that this plug a¹ does not project
laterally or horizontally beyond the groove of the strip.
A number of strips such as I have described are shown as arranged side by side in
close proximity to each other and to the side walls of the baths. They may be
fastened to the baths or they may be left unfastened, because in the latter case the
plates fitted to them will keep them in their proper positions relatively to the side walls
of tho baths.
may make the grooves a of the strips, so narrow that the strips will fit tightly
upon the lateral edges of the plates to be treated. Indeed the grooves may be
made so narrow that thoy can only be fitted to the plates by driving them onto the
plates.
It may be advantageous in many cases to form the plates to be treated in such sizes
that several, superposed one above the other will be required to extend from the lower
portion to the upper portion of the baths. Then, if the grooved strips by which they
are to be supported in the baths are adapted to fit tightly upon them, such strips may
be the means of uniting a set of the small plates into one compound plate as shown in
Figure 5.
It is not essential that the strips should severally be provided with but a single groove.
It will be advantageous to soak the strips with parafine if they shall be made of wood.
In any case the strips are to be made of nonconducting material.
The electrical current from the dynamo electric machine passes to the anode plates
of the electrolytic baths T and flows thence through the solution to the nearest of the
plates G of metal to be treated. It flows thence in the same manner from one to
another of the plates G and ultimately to the cathode plates of the baths. From the
cathode plates it proceeds to the anode plates of the baths T, and after passing through
these baths in the same manner as it passed through the baths T, it returns along the
wire B to the dynamo electric machine.
J designates a receptacle or roservoir which contains a supply of the electrolytic
solution.
K designates a pump which is employed to cause the flow of the electrolytic
solution through the baths T T and to effect the mixing of the solution in order that
it may be maintained as far as practicable in a homogeneous condition. This pump
causes the solution to flow from the reservoir J through the baths. After flowing
through the latter, it will return to the reservoir.
I do not desire to claim broadly the idea of circulating a solution through an
electrolytic bath or baths, nor do I wish to be confined to any specific manner of
effecting such circulation. A means whereby the solution may be circulated through
the baths satisfactorily to me in carrying out my improvement, I have illustrated in the
drawings and will now describe.
L designates a main supply pipe leading from a tank J¹, with which the dolivery
pipe of the pump is connected and which consequently receives the solution that is

page_text: conveyed by the pump from the reservoir J. This pipe L extends adjacent to the
several bathis so that it may deliver solution into them.
I may provide any desirable means for effecting the heating of the solution. I
have shown the tank J¹ as having combined with it, a compartment outside of that
compartment or portion which receives the solution; and in such extra compartment
I may arrange a steam coil or otherwise circulate steam so as to accomplish the desired
result.
From the main supply pipe L branch pipes L' extend. They communicate with
the baths near the top of the latter and have combined with them cocks L³ in order
that provision may be afforded for controlling the flow of the solution throngh them
into the baths.
The flow or circulation of the solution through the baths should be very gentle,
because it is undesirable to have any such agitation in the baths as will interfere with
the proper deposit upon the bottom of the baths of the foreign matters in the plates
to be treated when such foreign matters shall have been separated and dropped upon
the bottom of the baths. When the circulation of the liquid is downwards through
the baths it may be less apt to disturb the foreign matter deposited upon the bottom
of the baths, than if the circulation were in some other direction. It will be seen that
the baths have combined with them siphons Q whose shorter arms or limbs are within
the baths and extend close to the bottoms of the baths, yet not so close as to reach the
foreign matter deposited thereon.
The longer limbs of the siphons Qextend outside the baths and down into a
trough N which is located beneath the baths. The solution passing off through the
siphons will therefore be delivered into the trough N. The siphons do not as here
represented pass over the walls of the baths, but pass through the same near their
upper ends. Each of the siphons is provided with a hole 7 in the upper part of that
one of its limbs which is within the bath with which it is used. Whenever the solution
rises in a bath sufficiently high to cover the hole 7 of the siphon which is combined
with that bath, then the siphon will be rondered operative as a siphon and will there-
after continue to siphon out the solution from the lower part of the bath, until the
solution is lowered below the hole. After this the solution may still flow through the
siphon so long as its level remains above the lower portion of the interior surface of
the horizontal portion of the siphon. During the last described flow the operation of
the siphon will be that of an overflow pipe.
By employing siphon pipes for carrying off the solution I am enabled to remove the
solution from the lower part of the baths without appreciably agitating the solution
therein. Other outlets for the solution however, may, if preferred be used instead of
the siphon pipes.
The electric current passing through the baths will decompose the solution, the
anode plate and the plates G of the metal to be treated will be attacked so that their
sides which are the nearer to the cathode plates of the baths will be reduced and the
pure copper (assuming the anodes and the plates G to be made of copper combined
with other metals) will be deposited on the sides of the plates G which are the nearer
to the anode plates and also upon the corresponding sides of the cathode plates. This
action is illustrated in Figure 4, where the bold lines indicate the original condition of
these plates and the dotted lines show their ultimate condition. The precious metals
and other foreign matter will fall to tho bottom of the baths and may be taken
therefrom as occasion may require.
The deposited copper may be easily separated from such portion of the original
plates as may remain unchanged.
Precious metals may be separated in the manner described not only from copper but
also from lead and otlier metals.
The solution being naturally a little more dense at the bottom through electrolytic
action, the operation of drawing from the bottom and returning the heavier solution
at the top, tends equalize the density throughout. This is an important item in the
process.
The separation of precious metals from base metals is not the only purpose of my

page_text: process; for it is equally applicable to the separation from metals, generally of foreign
matters which may be incorporated with them.
By supporting the plates in the bath in the manner which I havo illustrated and
described as a feature of my improvement, a circulation of the solution beneath them is
provided for and the formation of spurs due to the collection of sediment immediately
adjacent to the bottom edges of the plates will be practically avoided; because when
those portions of the plates which are subjected to the electrolytic action of the baths
are isolated above the bottom of the baths, it will take a considerable time for sedi-
ment to accumulate upon the bottom of the baths to such an extent as to reach the
plates, and such time will be longer than the time required for the electrolytic action.
It is obvious that the formation of spurs and the collection of sediment including
metal would seriously impair the electrolytic action of the baths. Moreover when
the plates are supported in the manner I havo illustrated and described, they may be
arranged closer together than when arranged at an incline and supported across the
entire lower edge. Reduction of the resistance offered by the clectrolytic solution
will result from lessening the space between the plates.
Gentle circulation of the solution which I provide for is advantageous, in that it
tends to maintain the solution in a practically homogeneous condition and yet is
insufficient to interfere with either the electrolytic action or the proper deposit
upon the bottom of the baths of the foreign matter separated from the platos treated.
The advantages of that step of the treatinent which forms the subject of my
improvement and which consists in the rolling of the plates are numerous and
important. The rolling of the plates produces a greater homogeneity of the metal
than it would be possible to attain by casting plates. The tendency to the
formation of spurs or knobs during electrolytic action is reduced in proportion to
the homogeneity of the plates. Plates rolled and thereby condensed, compactod
and rendered practically homogeneous can be used of less thickness than if the
plates were merely cast. Indeed metal plates formel solely by casting, would be
so porous that if made thin they would soon become disintegrated or segregated into
numerous small parts when subjected to electrolytic action; whereas the rolled plates
may be subjected to electrolytic action and that action may be continued until tho
plates have been reduced as desired. The plates may be rolled to about one eighth
of an inch in thickness which is thinner than plates can be practically cast.
Moreover when metal is deposited. upon one side of the plates as in my process,
the smoothness of surface which is attained by rolling the plates is of advantage,
because it admits of making a smoother layer of the deposited metal.
Owing to the smoothness of the surfaces of the plates the thinness of the plates and
the consequent short period that the plates have to remain in treatment, I am
enabled to use a more dense current thereby increasing the rapidity of the deposit.
It is of great importance in other ways to bo able to use thin plates. Very many
more of such plates may be used in a bath than would be possible if thick plates wero
employed. The weight of metal under treatment is much less and the length of time
necessary for the treatment of the plates reduced. These advantages make it possible
to work a very much larger plant with the same capital than would be possible it
heavy cast plates were used. The lessoned time during which the plates undergo
treatment enables capital to be oftener turned and also reduces the liability to the
formation of spurs or knobs extending over to confronting plates.
Thin plates may also be handled much more easily than the other plates. Especially
is this true when the said plates are made in sections arranged one above another to
form a compound plate as suggested.
By the use of thin rolled plates which are practically homogeneous, the resistance to
the passage of the electric current offered by the solution between the plates may be
reduced because the plates may be arranged so that they will be closer together at all
times during the electrolytic treatment. The distance may be reduced even beyond that
reduction which is attributable to the method of supporting the plates which I have
shown and described. By reducing the resistance an economy of power is obviously
effected.

page_text: Having thus particularly described and ascertained the nature of my 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 process of treating metals consisting in rolling plates of the metal to be
treated, arranging such plates in an electrolytic bath, between an anode plate and a
cathode plate, without any connection between said plates which are to be treated, or
between any of them and the anode or cathode plate except through the electrolytic
solution and subjecting the plates to the action of a current of electricity, substantially
as specified.
2. The process of separating from copper and like metals, foreign matter which
may be incorporated with the same, consisting in arranging in an electrolytic bath an
anode plate and a cathode plate at a considerable distance apart, interposing between
them one or more plates of the metal to be treated leaving such plates unconnected
electrically except through the solution of the bath, supporting such plates above the
bottom of the bath so that the lower edge of the portions subject to the electrolytic
action will have nothing immediately below them, and subjecting the plates to the
action of a current of electricity, substantially as specified.
3. The process of separating from copper and like metals, foreign matter which
may be incorporated with them, consisting in arranging in an electrolytic bath an anode
plate and a cathode plate, interposing between the Intter one or more of the platos to
be treated, leaving the same electrically unconnected save through the solution in
gently circulating the solution from the upper to the lower portion of the bath, and
in subjecting the plates to the action of a current of electricity, substantially as
specified.
4. An electrolytic bath having side pieces provided with vertically extending
grooves closed at the extreme lower ends, substantially as specified.
5. An electrolytic bath having side pieces provided with vertically extending
grooves closed at the lower ends by means of plugs driven into their lower ends,
substantially as specified.
6. The combination with an electrolytic bath, of side pieces made independent of the
bath and provided with vertically extending grooves for receiving the side edges of
plates; said side pieces being driven onto the sido edges of said plates; substantially
as specified.
7. An electrolytic bath having its sides provided with vertically extending grooves
for receiving plates to be treated, and having supports for the plates arranged at the
lower ends of the grooves and of such width that they will not project horizontally
beyond the inner surfaces of the said sides of the bath, substantially as specified.
8. The combination of a number of electrolytic baths, a receptacle or reservoir for
containing electrolytic solution, a pump for conveying the solution from the receptacle
to the clectrolytic baths, a pipe extending from the receptacle, a conduit extending
adjacent to the baths and communicating with the said receptacle, branch pipes
extending from the pipe aforesaid to the said baths, cocks for controlling the branch
pipes and outlets for conveying the solution from the several baths to the said conduit,
substantially as specified.
9. The combination with an electrolytic bath, of a siphon extending into the same,
and a trough into which the siphon may discharge, the siphon being provided with a
hole in that liimb which extends into the bath, substantially as specified.
LIED TO AND MAT SI nar
1000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.