Improvements in the Electrolytic Treatment of Metals.
Year: 1890

page_text: Date of Application, 25th June, 1890
Complete Specification Left, 28th Mar., 1891-Accepted, 2nd May, 1891.
PROVISIONAL SPECIFICATION.
Improvements in the Electrolytic Treatment of Metals.
ALEXANDER WATT, 81, Fernlea Road Balham, Surrey, Electro-chemist do
hereby declare the nature of this invention to be as follows:-
39
In the reduction of metals by electrolysis, as in the process of refining copper
by the electrolytic method, for example, in which the cathodes, or receiving plates
consist of flat plates or sheets of metal, it is well known that after a time the
electro-deposited metal assumes a crystalline form at the edges and corners of
the plates, the metallic crystals, or "trees," as they are called often acquiring
considerable proportions; and if such nodular or tree-like growths are not removed
they are liable to extend until they come in contact with the anodes, when the
current becomes "short-circuited," as it is termed, bringing the operation to a
standstill.
The object of this invention is to prevent the metal under treatment in the
electrolytic baths from depositing upon the edges and corners of the plates and cause
it to deposit only upon the plane or flat surfaces, which the inventor has found
can be most effectually accomplished by protecting the edges and corners of the
plates or cathodes by means of a frame constructed of some suitable non-metallic
substance, such as wood, ebonite, or any suitable material not being a conductor
of electricity-a simple wooden frame answering the purpose perfectly well. The
several parts of a wooden or other suitable frame may be grooved, as in the
ordinary school slate, to receive the edges of the metallic plate or cathode, and
the frame being properly adjusted may then be secured or fastened at its corners
in any convenient way. The upper bar of each frame may be provided with one
or more slots or grooves to admit the "lug" or lugs, with which such plates
are usually provided, such lugs being used, as is well understood; for suspending
the plates in the electrolytic tank from the usual conducting rods.
Dated this 28th day of June 1890.
ALEXANDER WATT.
COMPLETE SPECIFICATION.
Improvements in the Electrolytic Treatment of Metals.
ALEXANDER WATT, 81 Fernlea Road Balham, Surrey, Electro-chemist 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 invention is to prevent, or at least in a great measure to check
the formation of crystalline nodules, or "trees," as they are commonly called, upon
the edges of the cathodes or receiving plates used in the reduction of metals by
electrolysis, as in the well-known process of copper refining by the electrolytic
method. It is well known that when considerable quantities of copper, zinc or
other metals, are deposited upon flat sheets of metal, forming the cathodes or
negative electrodes, that the metal deposited at the edges of the plates frequently
assumes a crystalline form, the metallic crystals sometimes acquiring considerable
dimensions and become a source of great trouble during the electrolytic operation,
since they are liable to extend in growth until they reach the anodes, or positive
electrodes, and in so doing place the current on "short circuit," as it is termed, and
thus prevent the further deposition of the metal.

page_text: To carry out this invention, I enclose each plate, or cathode, in a frame
constructed of some non-metallic substance, as wood, ebonite, or any other suitable
non-metallic material, a wooden frame answering the purpose perfectly well.
When using wooden frames however, I prefer to employ a hard wood, and I find it
advantageous to coat this material with varnish to render it less liable to absorb
the liquid of which the electrolytic bath, or solution, is composed. The several
parts of the frame are provided with slots or grooves, into which the edges of the
plate are inserted, and the parts of the frame are connected and secured in their
proper places in any convenient way. The upper bar of each frame may con-
veniently be provided with a slot or groove through which the "lug," or "lugs,"
with which such plates are sometimes furnished, may pass, these lugs as is well
known, being used for suspending the plates, or cathodes, in the solution or
electrolyte from the usual conducting rods. Respecting the form of frame to be
employed for the purposes of this invention, or the material of which it may be
composed, these may be varied according to the taste or inclination of the user, but
it is preferable to have the frame-work bevelled, from the outer edges inward, so
that more or less sharp edges shall be presented to the exposed surfaces of the
plate, whereby the plate becomes more fully exposed to the direct influence of the
anode. A suitable frame may also be prepared from cylinders of wood, or other
suitable material, slotted or grooved as described, to receive the edges of the
plates, or any modification that will practically answer the purpose may be adopted,
the object being to prevent the edges of the plates from receiving the metallic
deposit during the electro deposition of the metal for the reasons before described.
Having thus fully described the nature of my said invention, and the manner in
which the same may be carried into effect, I wish it to be understood that I do not
confine myself to any particular form, or material, in the construction of the frame
referred to in the foregoing description of my invention, but what I claim as my
invention is:-
The application of a frame, or framework, to the edges of the cathodes, or
receiving plates employed in the electro-deposition of metals for the purpose herein
described.
Dated this 28th day of March 1891