Improvements in and connected with the Extraction of Gold by Electrolysis.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in and connected with the Extraction of Gold by
Electrolysis.
I, OCTAVIUS MARCH, of 53, Victoria Street, Westminster, in the County of
London, Electrical Engineer, do hereby declare the nature of this invention
to be as follows:-
The object of my invention is the extraction of gold from ores, silts, tailings,
slimes etc. by electrolysis in a more economical manner than heretofore.
In carrying out my invention I preferably employ an apparatus arranged as
follows:
I make use of a suitable vessel of any convenient shape having the bottom
floored or tiled with carbon plates and having attachments for electrical con-
nection brought through the bottom of the vessel.
This Hoor of carlon plates forms the anode. The vessel is then partly filled
with crushed ore, silt, tailings, slimes or other matter containing gold, and a
Bolution of any suitable chloride such as sodium chloride.
At the upper part of such vessel 1 place a tray with perforated bottom and
covered with a suitable porous diaphragm, the bottom of such tray being below
the surface of the solution. In this tray, I place a plate of metal, carbon, or
other suitable material to form the cathode.
If it be desired to collect the gold as an amalgam mercury is put in the tray
containing the cathode.
When this apparatus is connected with a suitable electric current chlorine is
liberated at the anode, gold chloride is formed which is again split up and the
gold deposited upon the cathode or retained by the mercury as an amalgam.
Dated this 23rd day of November 1897.
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents.
Improvements in and connected with the Extraction of Gold by
Electrolysis.
I, OCTAVIUS MARCH, of 53, Victoria Street, Westminster, in the County of
London, Electrical Engineer, do hereby declare the nature of this invention
Price 8d]

page_text: 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 my invention is the construction of an electrolytic cell for use
in the extraction of gold from ores, silts, tailings, slimes etc. and for performing
other electro-chemical operations in a more convenient and economical manner
than heretofore.
The apparatus hereinafter described may be used for the extraction of gold
from any auriferous material by direct chlorination therein, and the simultaneous
generation of sodium amalgam, or it may be used as a separate generator of
chlorine gas and sodium to be afterwards used in connection with gold extraction,
or for the electro deposit of gold from solution.
In the accompanying drawing: Fig. 1 shows a vertical section of an electro-
lytic cell constructed according to this invention and suitable for the extraction
of gold. Fig. 2 shows the cathode pot.
The cell comprises a vessel built of wood having carbon plates or blocks a
set in the bottom with bitumen, paraffin wax or other suitable material band
whose carbon studs e pass out through the bottom and have their extremities
copper plated, a suitable conductor being connected with them and carried
to the terminal e, any desired number of carbon plates of any desired form
may be employed in one cell. For convenience the sides of the cell are
extended below the bottom y. When this form of cell is used for chlorinating
purposes the carbon plates set in the bottom as hereinbefore described form the
anode, and if it be used for direct chlorination of auriferous material within the
cell itself the material to be so treated is placed in the cell with a solution
of sodium chloride. The cell has a lid cover resting on supports and this lid
carries the cathode pots m which drop into holes in the lid and rest upon
Hanges the said supports which carry the lid being below the water line
so that the lid is sealed and forms a trap for the gases liberated in the cell..
The cathode pots are fitted into the lid in such a way that their flanges form
air tight joints, this being obtained by rubber packing, clay luting or other
convenient means. The lid is fitted with a tube which may be placed in any
convenient position and by means of which the liberated gases, such as chlorine
may be carried off.
The cathode pots are constructed of porcelain or other suitable material and
are made in three parts comprising an outer pot m perforated all round a little
above the bottom with holes p, an inner pot q having its bottom perforated
all over with holes, and a plain cylindrical sleever over the bottom of which a
piece of linen canvas or other suitable fibrous material is stretched before
it is inserted in the inner pot g. These three parts when put together with a
suitable piece of linen or canvas form a porous pot having very little electrical
resistance and suitable for use with a mercury cathode. The fabric s preferably
extends beyond the edges of the sleeve and fills part of the space between
the sleeve and the inner pot q. Mercury to the desired depth is placed on 'the
fabrics on the perforated bottom of the pot q and any mercury or amalgam
dripping through said pot falls into the bottom of the outer pot m and are
retained therein owing to the holes being some distance above the level of its
bottom. A convenient method of making electrical contact with the mercury
placed in the cathode pot is as shown in Fig. 1 to put a perforated disc of copper
of the same diameter as the outside of the sleeve r at the bottom of the sleeve
before stretching over the linen. This copper disc has a conducting rod attached
to it ending with a terminal w and covered with insulating material but any
other suitable means of making contact may be adopted.
t
When a cell constructed as above described having been charged with auri-
ferous material and sodium chloride, is connected with a suitable electric current,
chlorine is liberated at the anode and sodium at the cathode, the carbon being
the anode and the mercury the cathode. The chlorine rising from the anode

page_text: permeates the auriferous material hand, combining with the gold, forms gold
chloride while sodium is liberated at the cathode and, combining with the mer-
cury forms solium amalgam. By properly adjusting the electric current the
gold chloride can be broken up and the gold deposited in the mercury that is
to say--the energy required to decompose the gold chloride is less than that
required to form it. In practice I find that with 6 volts or more the chloride
is formed and with 3 to 4 it is decomposed.
For the electro deposit of gold in solution the cell can be used in the following
way: The carbon plates in the bottom can be used as cathodes and covered
with a film of mercury. The cell may be filled with a solution of gold, the lid
and pots dispensed with and an anode of zinc or other suitable material suspended
in the upper part of the solution. By means of the electric action set up in the
cell so arranged or by external current, the gold can be thrown down into the
mercury.
An alternative method of using this apparatus as a cell for the deposit of
gold in solution is to replace the bottom carbon plates by zinc plates otherwise
arranging the cell as shown in the drawing with the lid and cathode pots in
place. The cell is then filled with the gold solution to be treated and the circuit
closed between the zinc anode and mercury cathode. A suitable resistance may
be included in such circuit if desired.
If it be desired to use the cell for the generation of chlorine and sodium it is
arranged as in the drawing except that no auriferous material is placed in it.
the cell containing only brine of a suitable density. The mercury in the cathode
pots when sufficiently charged with sodium can he removed by lifting out the
inner pots, and they can be removed, emptied, re-filled and replaced without
breaking the water seal or interrupting the electric circuit. Fresh brine can
also be inserted by lifting out an inner pot and pouring it into an outer pot.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
1. In an electrolytic cell the combination with a containing vessel, of carbon
plates or blocks set horizontally in the bottom of the said vessel and having
carbon studs passing through it and adapted to be connected together and to a
source of electric energy, substantially as described.
2. In an electrolytic cell the combination with a containing vessel of a porous
pot, usually a cathode pot, comprising an outer pot perforated at a short distance
above the bottom thereof and jointed to the cover of the said vessel, an inner
pot with perforated bottom, an inner sleeve or open tube inserted into the said inner
pot, and a piece of fibrous fabric stretched across the lower orifice of the said
sleeve or tube and held firmly between it and the inner pot substantially as
described and for the purpose set forth.
3. In an electrolytic cell the combination with a containing vessel of a porous
pot, usually a cathode pot, comprising an outer pot perforated at a short distance
above the bottom thereof, an inner pot with perforated bottom, an inner sleeve
or open tube inserted into the said inner pot, a perforated disc of metal fitting
the lower end of the said sleeve or tube and having a conducting rod covered
with insulating material, a piece of fibrous fabric stretched across the said disc
and held firmly between the said sleeve and inner pot, and a layer of mercury
placed on the said fabric and inside the sleeve substantially as described.
4. An electrolytic cell comprising a containing vessel having a cover provided
with a liquid seal, horizontal carbon plates or blocks set in the bottom of the
said vessel and provided with studs passing through it and adapted to be con-
nected together and to a source of electrical energy; and a porous pot comprising
an outer pot perforated at a short distance from the bottom thereof and fitting
in the cover of the containing vessel, an inner pot with perforated bottom, an

page_text: inner sleeve or open tube inserted into the said inner pot, and a piece of fabric
stretched across the lower orifice of the said sleeve or tube and held firmly
between it and the inner pot.
Dated this 23rd day of August 1898.
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents.