A NEW OR IMPROVED PROCESS AND APPARATUS FOR SEPARATING COMPOUNDS OF METALS BY ELECTROLYSIS
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by Lyman Elmore at the Office of the
-Commissioners of Patents on the 27th March 1883.
LYMAN ELMORE, of New York City, in the United States of America, at
present residing at the Royal Hotel, in the City of London. "A NEW OR
IMPROVED PROCESS AND APPARATUS FOR SEPARATING COMPOUNDS OF METALS BY
ELECTROLYSIS."
The general object of this invention is the refining and separating of metals by
Electrolytic action, and more especially the refining of metallic ores, alloys or base
bullion, by separating the gold, silver, nickel, copper and other metals contained
therein.
The general principles of the process of dissolving metals, and depositing them
from their solutions by the aid of electricity, are well known. The process consists
in exposing one or more anodes, composed of the metals or alloys of metal to be
operated upon, to the action of a suitable solvent solution in an electrolytic bath,
in which bath the cathode is also immersed. When the positive pole of a dynamo-
electric generator or other suitable source of electricity, is connected with the
anode, and its negative pole in like manner with the cathode of the electrolytic
cell, the coarser metals, such as copper and silver, contained in the anode are
dissolved and thus separated from the gold.
In carrying out this process in the manner heretofore practised, it has been
found that the dissolved silver in the form of sulphate of silver, which is contained
in the solution, is precipitated by contact with the metallic copper of the anode, or
with the hydrogen set free by electric action, and is thereby mingled with the
undissolved or fine gold which falls from the anode to the bottom of the containing
cell, while the copper is deposited upon the cathode. This result renders it
necessary to employ additional processes for separating the silver from the gold.
•
The present Invention is designed to overcome these objections, and to secure a
complete separation of.the gold and other insoluble metals in the solution from the
baser or other metals. To this end use is made of an improved anode or positive
element, composed of material which is a conductor of electricity, and which is not
soluble in the solution employed. Such an anode may be formed of metal, or of
carbon, or other conducting metalloid, and it may be either porous or non-porous,
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page_text: but preferably porous. This anode is hollow and forms a cell or receptacle, which
is suspended in a tank or vat containing a suitable solvent solution, such for
example as sulphuric acid. The anode itself, or a plate or mass of bullion
suspended within it, or both in some cases, is, or are united with the positive pole
of a dynamo-electric machine or other suitable source of electricity. The interior
of the hollow anode is also filled with the sulphuric acid or other suitable solution.
Within the outer solution, but outside the hollow anode, and preferably in close
proximity thereto, is suspended a copper or other equivalent cathode connected
with the negative pole of the electric generator.
It will be understood that any
required number of hollow anodes with their corresponding cathodes may be
suspended alternately within a single tank or vat and connected as herein before.
stated with the respective poles of the electric generator.
The manner in which the improved process is carried out is as follows:-
The base bullion or ores containing the alloy of copper, silver, gold and other
metals is cast into plates, bars or ingots, or broken into masses, or any other
convenient form, and placed within the receptacle formed by the hollow anode.
A copper or other cathode is also provided, which is placed outside the hollow
anode. When a powerful current of electricity is made to traverse the apparatus,
the electrolytic action will attack and dissolve the soluble metals contained in the
bullion within the hollow anode. If a porous anode, such for example as carbon,
be employed, the copper and silver in solution will be carried through the pores of
the same and the copper will be deposited upon the cathode, while the silver, or
After the removal
the greater part thereof, will. be precipitated in the outer cell.
of the silver.and copper from the bullion or ores, the gold will fall to the bottom
of the anode cell, and will accumulate there. If any portion of the silver in
solution, before passing through the walls of the anode, should be precipitated
within the hollow anode, it will be redissolved whenever it comes in contact with
the conducting walls or with the gold at the bottom of the receptacle, which is also
a conductor and in electrical connection with the anode, so that the only metallic
deposit within the anode will consist of gold or other substance insoluble in the
solution employed.
If the hollow anode is formed of a non-porous conducting substance, the solution
containing the copper and silver is removed therefrom by means of a siphon, pump,
or faucet into another suitable receptacle, after which the silver may be precipitated
from the solution by any of the well known processes suitable for the purpose,
while the copper solution may be returned to the outer tank or elsewhere, and the
copper contained therein may be deposited upon the cathode, or the copper may be
extracted from the solution by other means. When the last described modification
of the process is employed, the solution containing silver and copper when removed
from the hollow anode by siphons or otherwise as fast as it becomes saturated, is
replaced by fresh solution. The sulphuric acid or other solution in the outer tanks
.may be used again within the hollow anode after its metallic silver has been
precipitated and its copper deposited.
The most essential feature of my invention consists in the employment of the
hollow anode of conducting material. A diaphragm of porous non-conducting
material would serve equally well to retain the undissolved gold, but inasmuch as
the latter, when separated and thrown down, would be electrically insulated from
the anode the silver would necessarily be precipitated upon it and mingled with it,
whereas in this method the gold, being electrically a part of the anode, acts to
redissolve any silver which may be precipitated upon it, and so retain it in a state
of solution until it passes into the outer cell or is otherwise removed.