Year: 1888

page_text: burgh, Transvaal, South Africa, Mining Engineer.
I, WILLIAM PHILLIPS THOMPSON, F.('S., M.I.M.E., of the Agency for Foreign
Patent Solicitors, 6, Lord Street, Liverpool, and 6, Bank Street, Manchester, both in
the County of Lancaster, and 323, High Holborn, in the County of Middlesex, Civil
Engineer, do hereby declare the nature of this invention to be as follows
-
The invention relates to the extraction of gold and silver from their ores, by
means of chlorine, bromine, or iodine, and mercury, and the application of electricity
for decomposing and amalgamating
(1) The ore after being pulverized by suitable means, is placed into rotating
vats, or vats made to agitate their contents, with a sinall quantity added of chlorine,
bromine, or iodine separately, or mixtures of chlorine bromine or iodine or chemicals
which produce chlorine, bromine or iodine, and some water The contents of the
vats are then subjected to a pressure of air or steam which may be anything above
the atmospheric pressure, and the vats put into motion for a short period of time
which may vary from a few minutes to several hours, according to the nature of
the ore.
Mercury or Sodium Amalgam is next added to the ore and solution either in the
same or other vats, and pressure of air or steam again applied to the contents, and
the contents agitated as before.
By these means the gold which came into solution, in the first instance, is
precipitated and amalgamated with the mercury. The vats containing the ore,
amalgam, etcetera, ale next emptied into a receiver, and the ore, amalgam,
etcetera, is washed down an inclined table of amalgamated copper by jets of water
which carry the ore etcetera to the foot of the table, and thence to what my
correspondent calls electrolytic cells. Part of the amalgan remains behind on the

page_text: copper plate and the remainder in the electrolytic cells. The gold or silver is obtained
from the amalgam in the usual way
If thought advisable, before adding the mercury, the gold in solution may be
leached out, and precipitated by any known means, and the gold or silver remaining
in the ore is extracted as above described.
(2) The Electrolytic Cells
These consist of a number of narrow boxes or troughs made of some non-conductor
of electricity. and with mercury cathodes, and carbon, platinum or lead peroxide
anodes
These boxes or cells are arranged in the form of steps, that a liquid may flow
over each cell and fall into the next. The bottom of each cell is covered with
mercury and the mercury is connected with the negative pole of an electric
generator, so that the mercury acts as a cathode The positive pole has an anode
made of carbon or other suitable material, and is suspended in each cell at a
convenient distance from the mercury, so as to admit of the ore etcetera which is
washed down the amalgamated copper plate, passing between the anode and
athode The amalgamated copper plate is connected with the negative pole of the
electric generator
The action of the electrolytic cells is as follows
The ore on leaving the vats may contain some gold or silver compounds and also
some floured mercuiv, or floured amalgam, and metallic gold To prevent these
being lost, the whole of the ore and solution is passed through the electrolytic cells.
A current of electricity is kept constantly flowing between the anode and cathode
and during the passage of the ore and solution through the cells, any gold or silver
compounds that may be present with the ore are decompo od, and the gold or silver
goes to the mercury cathode where they readily amalgamate. Any floured mercury
or floured amalgam, and metallic gold are also retained.
The mode of operation is as follows
The ore which has been pulverized by suitable means, is placed into the vat
through a manhole with some chlorine, bromine or iodine added. The manhole 18
next closed and air on steam forced into the vat until a pressure of 60 to 80 pounds
to the square inch is reached, above the atmospheric pressure While under this
pressure, the vat is caused to agitate the contents by revolving on horizontal axis,
or other means for about one or two hours The manhole is next opened and some
mercury or sodium amalgam added, and the manhole is closed again and air or steam
forced into the vat as before
The contents are again agitated for a short time, and are then emptied into a
receive, and washed down to distribute the ore etcetera, over an amalgamated copper
plate, and thence fall into electiolytic cells.
The electrolytic cells have mercury at the bottom of each, connected with the
negative pole of an electric generator, and have anodes suspended so as not to touch
the mercury The mercury acts as the cathode, and a constant flow of electricity is
kept up between the anode and cathode, and at the same time the ore etcetera passes
through the cells
The chemicals placed in the vat, along with the ore, dis-olve, or partially dissolve
the gold that may be present, and the silver is converted into an insoluble compound.
Upon the addition of mercury the gold in solution is precipitated and amalgamated
by the mercury. The gold that did not come into solution is prepared that it readily
amalgamates with the mercury. The pressure of air or steain inside the vats
accelerates the gold to solution and hastens the operation of precipitation and
amalgamation
01 silver
The electrolytic cells are to decompose and amalgamate any gold
compounds, and to retain floured mercury and floured amalgam and metallic gold
which might otherwise escape with the tailings. When the compounds of gold or
silver pass into the electrolytic cells, the compounds are decomposed and the gold
or silver goes to the mercury cathode, as in electrolysis, when they readily
amalgamate.

page_text: manner.
The floured mercury and floured amalgam are retained in a somewhat similar
The appliances for this process, described above, may from time to time
be altered and rearranged, but the process will remain the same.
Dated this 6th day of June 1888.
WM. P. THOMPSON & Co.,
Agents for the Applicant.
Improvements in or relating to the Treatment of Ores for Facili-
tating the Extraction and Recovery therefrom of Gold and Silver
and in Apparatus therefor.
A communication from abroad by HENRY FORBES JULIAN, of Frazer Street, Johannes-
burgh, Transvaal, South Africa, Mining Engineer.
I, WILLIAM PHILLIPS THOMPSON F.C.S, M.I.M.E., of the Agency for Foreign
Patent Solicitors, 6, Lord Street, Liverpool, and 6, Bank Street, Manchester, both in
the County of Lancaster, and 323, High Holborn, in the County of Middlesex, Civil
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 :-
This invention relates to an improved process of and apparatus for the extraction
and recovery of gold and silver from ores by means of the action of chlorine, bromine,
or iodine and mercury, and to the application of electricity for decomposing and
amalgamating.
The invention may be understood by the following description, reference being had
to the accompanying drawings, in which
Figure 1 is a side elevation, partly in section, of a plant adapted to effect the
purposes of the invention.
Figure 2 is a front elevation of the same, and
Figure 3 is a plan.
The ore, after being pulverised by suitable means, is placed in a rotatable vat or
a vat constructed with apparatus adapted to agitate its contents, the said vat being
preferably constructed of such materials as are not acted upon to any great extent by
the chemicals employed within_it Such a rotating vat is shown at A. It is
mounted upon
a horizontal axis I, and is driven from the belt pulley H', through th
medium of gearing H, H.

page_text: With the ore in the vat there is added a small quantity of chlorine, bromine, or
Iodine, or of a mixture of two or all of these substances, or of chemicals which
produce chlorine, bromine or iodine There is also added as much water as will
reduce the mass, after agitation, to the consistency of a semi-liquid mud
The manliole of the vat is then closed by a tight cover such as B, and the contents
subjected to the pressure of air, steam, or other fluid by means of any suitable device,
such as an air compressor G which is driven by the gear H¹ H H' and has its
outlet connected with the hollow shaft I. The pressure may be almost anything
above that of the atmosphere. About 60 to 80 lbs. to the square inch will suffice in
most cases.
The vat is now rotated while under pressure, and its contents agitated for a period
sufficient to cause them to assume the consistency of a uniform semi-liquid mud.
This period may vary from a few minutes to several hours, according to the nature
of the ore under treatment, and the pressure applied to the contents in the vat, one or
two hours being a usual time
In the above operation the gold is wholly or partly dissolved by the action of the
chlorine, bromine, or iodine aided by the pressure within the vat, while the silver is
converted into an insoluble compound, which may be, for example, a chloride,
bromide or iodide, according to which chemical or chemicals have been employed.
The gold which is not dissolved, is, however, so prepared, that it will readily
amalgamate with mercury, in the following operation.
The manhole of the vat is now opened, and a quantity of mercury or sodium
amalgam 18 added to the semi-liquid mass, either in the same vat or in another one.
The manhole is then closed, the pressure of the air, steam, or other fluid, again
applied to the contents, and the latter are then preferably agitated as before, but only
for a few minutes as a general rule.
The
In this operation the gold is readily precipitated by the mercury and formed into
an amalgam, and a portion of the mercury replaces the gold so precipitated
pressure within the vat also accelerates the operation of precipitation and
amalgamation
If thought advisable, the portion of the gold contained in solution may, before the
mercury is added, be leached out and precipitated by any known means, and the
gold and silver remaining in the ore may then be extracted therefrom, as above
described
After the above second operation the cover B is removed and the contents of the
vat emptied into a receiver C, where they are allowed to settle for a short time. The
receiver has preferably a sloping bottom and is provided with outlet openings c which
are controlled by slides C¹
be
After settling, the slides C¹ are drawn up and the ore, amalgam, etcetera, on issuing
from the openings care, by means of jets of water, washed down and distributed
over one or more inclined plates D of amalgamated copper The water jets may.
supplied by a perforated pipe placed in front of the openings c
l
The plates D are
so inclined that the ore etcetera may be washed off them readily, the inclination being
about one inch to the foot. Each plate is connected, preferably at its foot, (as
shown), to the negative pole of an electric generator, for a purpose hereinafter set
forth
After the passage of the material over the plates D and also, if desired, before its
passage over the same, it is caused to pass through a series of electrolytic cells E,
arranged successively one below the other so that a liquid may flow through one
and fall into the next. The cells consist of a number of narrow troughs or boxes,
preferably made of some non-conductor of electricity, and each provided with a
cathode F¹ of mercury, (or sodium or potassium amalgam), connected with the
negative pole of an electric generator, and with an anode F of carbon, platinum,
lead peroxide, or other suitable material which is connected with the positive pole of
the said generator. The mercury cathode F¹ is placed at the bottom of the cell, and
the anode F is supported above, and at a convenient distance from it. The anodes F
thus serve as vertical partitions for the cells E and the material washed down from

page_text: the receiver and plates D falling successively into the cells, 14 obliged to pass
through each, between its anode and cathode I desirable, the anode F may be
imply at ached to the lower edge a suitabl⚫ vertical parntion of some other
material The number of such cels wul vary according to circumstances, but usually
fou to nine are found to be ample The cells it the he is of the copper plates D
e similar to those below them, but the mercury cathodes F¹ are connected to the
negative pole of the generator by means of the plates which are extended backwards
as shown so as to form the bottoms of th cells in direct contact with the mercury
cathodes
'
The action of the electrolytic cells and copper plates is as follows
_
The ore on leaving the vat may contain some gold or silver or mercury compounds,
and also some floured mercury or floured amalgam and metallic gold To prevent
any of these being lost in the tailings the whole of the ore and solution is passed
through the electrolytic cells and over the copper plates, wh'e a strong current of
electricity is kept constantly flowing from the anodes to the cathodes. During the
passage of the ore and solution through the cells, any gold and silver compounds that
may be present are decomposed and the gold and silver go to the mercury cathode
where they readily amalgamate and are retained. Any floured mercury or floured
amalgam and metallic gold that may be present are also retained in a somewhat
similar manner.
Part of the amalgam in the solution is retained by the amalgamated copper
plates D. These are used as a guide to the operator in order that he may see what is going
on. They should be kept covered with sodium or potassium amalgam. This may
be done by allowing a solution of potassium or sodium compounds, such as salt, soda,
or potash, to pass through the cells and over the plates while the current of electricity
is passing.
This solution may be conveniently kept in a vessel K placed above the upper cell
and provided with a suitably controlled outlet pipe as shown
The sodium or potassium of the solution is deposited and amalgamated at the
mercury cathodes, while the element with which it was combined, is liberated at the
anodes.
The gold or silver may be obtained from the amalgam in the usual way.
It will be obvious that the form of the plant for carrying out the above process
may be modified considerably without altering the process itself.
Having now particularly described and ascertained the nature of the said inven-
tion, 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 for extracting and recovering gold and silver from their ores, which
consists in agitating the pulverised one under pressure with water and with chlorine,
bromine or iodine, in then adding mercy and again agitating under pressure, 1
afterwards passing the resultant mixture over one or more amalgamated copper
surfaces in electrical contact with the cathode of an electie cucuit, and in finally
submitting the mixture to electrolytic action between mercurial cathodes located below
it, and suitable anodes, such as described, immersed in it at a convenient distance
above the cathodes, substantially as set forth
2 The improvement in the process for extracting and recovering gold and silver
from their ones, which consists in agitating the pulverised ore under pressure with
chlorine, bromine or iodine and water, and in adding mercury and again agitating
under pressure, after the gold and silver have combined with the halogen or have
been otherwise prepared by it for amalgamation, substantially as described
3. The improvement in the process for extracting and recovering gold and silver
from their ores, which consists in adding mercury to the mixture of pulverised
chlounated, brominated, or iodinated ore and water, and agitating the whole under
pressure, substantially as described
The improvement in the process for extracting and recovering gold and silver
from their ores, which consists in passing the mixture of chlorinated, brominated,

page_text: or iodinated ore, gold and silver amalgam, mercury, and water over one or more
amalgamated surfaces in electric contact with the cathode of an electric circuit,
whereby part of the amalgam of gold and silver is 1etained on said surface or surfaces,
substantially as set forth
5 The improvement in the process for extracting and recovering gold and silver
from their ores, which consists in passing the tailings, that still contain (1) gold or
silver (2) gold or silver halogen compounds (3) floured mercury or amalgam and
(4) water, over one or more mercurial cathodes and under one or more opposing
anodes, preferably of carbon, immersed in the mixture during the passage of an
electric current, whereby the halogen compounds of gold or silver are decomposed,
and the gold, silver and floured mercury or amalgam retained by the mercury cathodes,
substantially as described.
IT 1
1
WM. P. THOMPSON & Co.,
Agents for the Applicant.