Improvements in Obtaining Gold and Silver from Ores and other Compounds, and Apparatus therefor.
Year: 1894

page_text: Date of Application, 20th Feb., 1894
Completa Specification Left, 19th Nov., 1894-Accepted, 20th Mar., 1895
PROVISIONAL SPECIFICATION.
Improvements in Obtaining Gold and Silver from Ores and other
Compounds, and Apparatus therefor.
I, JAMES NICHOLAS, of Waterloo, in the County Palatine of Lancaster,
Manufacturing Chemist, do hereby declare the nature of this invention to be as
follows:-
This invention has principally for its object the obtaining of gold from its ores
or other compounds but it is also applicable for obtaining silver from its ores and
other compounds, and it also comprises an improved process and apparatus which
while applicable to ores and other compounds generally is effectual with ores and
other compounds from which gold and silver hitherto have not been easily
obtainable because of the presence of various other metals or their compounds or
because of the physical or chemical conditions of the gold and silver in the ore or
other compounds. The ore or other compound in a powdered condition is treated
with oxalic acid only, or with oxalic acid in conjunction with a hypochlorite either
or both. If the ore or other compound be treated with oxalic acid only then it is
but a preliminary treatment to some other process such as the cyanide amalgamation,
or chlorination processes for the purpose of extracting gold and silver from ores
and other compounds than the process hereinafter described. But if oxalic acid is:
used in conjunction with a hypochlorite then the extraction of the gold contained
in the ore or other compound may be obtained in solution the gold in it being
converted into chloride of gold without the aid of any other process while any silver.
which is present will be converted into chloride of silver and will be retained in the
ore or other compound which has been so treated.
The method which I have adopted by preference in carrying out this invention
is as follows. I reduce the ore or other compound containing gold and silver
to a pulverulent condition and then saturate it with a solution of oxalic acid
and this I do in the following manner. The powdered ore or other compound is
conveyed into a vessel made of suitable material. This vessel is constructed with
a perforated false bottom covered with a filtering web. This vessel is also furnished.
with un upright geared shaft and to this shaft are attached arms to act as stirrers..
At the bottom of these arms are placed scrapers or brushes so arranged that when
the shaft revolves in and stirs the powdered mass under treatment these scrapers
or brushes will graze or lightly rub the filtering web and so keep open its pcres,
prevent clogging and so permit the free filtration or drainage of the liquid from
the ore or other compound under treatment. The vessel may also be so constructed
that an arrangement to hasten filtration by suction may be adapted if desired and
it may also be so constructed that operations in it may be conducted under pressure
if pressure is deemed necessary. The pulverized ore or other compound which has
been placed in the vessel is saturated with oxalic acid solution which for convenience
is stored in a vessel and placed at a higher level than the first mentioned vessel,
such saturation being accomplished by either upward or downward percolation or
by both.
When the ore or other compound is completely saturated with the
oxalic acid solution and shows strong acid reaction, liquid hypochlorite of lime
(which for convenience is stored in a tank similarly placed) is caused to percolate-
by either upward or downward filtration or by both through the pulverized ore or
other compound which has been saturated with the oxalic acid solution and this

page_text: percolation of the hypochlorite of lime solution is continued until a strong
persistent chlorous odour begins to rise from the ore or other compound which is
under treatment. When this chlorous odour is distinctly and persistently
discernable the flow of the hypochlorite of lime solution is arrested and time
allowed for the various reactions to take place and these may be hastened by
causing the shaft in the first mentioned tank to revolve. After the lapse of a
sufficient period (generally about one hour) the reactions are complete and the
liquid matter is drawn off from the powdered ore or other compound which has
been under treatment, by means of a cock and run into a fourth tank so constructed
that its contents may be heated if desired by means of a steam coil or otherwise.
After the liquid matter has been run off the treated pulverized ore or compound is
well washed with water, the washing being effected by water being run into the
first mentioned tank and by causing the shaft in it to revolve. This water is next
run off and added to the liquid in the fourth tank.
The precipitation of the gold along with other matter is then effected by adding
a sufficiency of stannous chloride. This precipitation may be hastened and
perfected by beat, but heat is not necessary to be applied if a reasonable time is
allowed for complete precipitation say 12 hours. The precipitate is collected,
washed with water, dried, calcined or cupelled to get rid of foreign matter and the
gold in it is then melted and run into bars and will be found if the operations have
been properly conducted practically chemically pure.
The ore or other compound from which the said extraction of gold has been
made still contains its silver, which being in the form of chloride of silver has not
been dissolved out by either the chlorous solution or the water, but it is recoverable
by using any of the known solutions in which chloride of silver dissolves in and
then proceeding according to known means to procure
it in its metallic
condition.
It is manifest that the operation which has been described can be varied and
milar results obtained in a variety of ways, viz. :-The order of saturation with
the solutions may be reversed. The oxalic acid and the hypochlorite of lime one
both may be mixed with the pulverized ore or other compound in a dry or
partially dry condition and the reactions necessary to be obtained by saturation
with water.
Dated this 20th day of February 1891
Improvements in Obtaining Gold and Silver from Ores and other
Compounds, and Apparatus therefor.
I, JAMES NICHOLAS, of Waterloo, in the County Palatine of Lancaster,
Manufacturing Chemist, do hereby declare the nature of this invention and in
what manner the same is to be performed to be particularly described and
.scertained in and by the following statement:-
This invention has principally for its object the obtaining of gold from its ores
⚫r other compounds but it is also applicable for obtaining silver from its ores and
<ther compounds, and it also comprises an improved process and apparatus which
while applicable to ores and other compounds generally is effectual with ores and
other compounds from which gold and silver hitherto have not been easily obtainable
because of the presence of various other metals or their compounds or because of
the physical or chemical conditions of the gold and silver in the ore or other
compounds. The ore or other compound in a powdered condition is treated with
oxalic acid only, or with oxalic acid in conjunction with a hypochlorite either or
both. If the ore or other compound be treated with oxalic acid only then it is but

page_text: a preliminary treatment to some other process (such as the cyanide amalgamation
or chlorination-processes for-the-purpose-of-extracting-gold-and silver from -ores-
and other compounds) than the process hereinafter described. But if oxalic acid
is used in conjunction with a hypochlorite then the extraction of the gold contained
in the ore or other compound may be obtained in solution the gold in it being
converted into chloride of gold without the aid of any other process while any silver
which is present will be converted into chloride of silver and will be retained in the
ore or other compound which has been so treated.
The method which I have adopted by preference in carrying out this invention
is as follows:-I reduce the ore or other compound containing gold and silver to a
pulverulent condition and then saturate it with a solution of oxalic acid (say 1 lb.
of acid to 100 gals. of water) and this I do in the following manner. The powdered
ore or other compound is conveyed into a vessel made of suitable material. This
vessel is constructed with a perforated false bottom covered with a filtering web.
This vessel is also furnished with an upright geared shaft and to this shaft are
attached arms to act as stirrers. At the bottom of these arms are placed scrapers.
or brushes so arranged that when the shaft revolves in and stirs the powdered mass
under treatment these scrapers or brushes will graze or lightly rub the filtering web.
and so keep open its pores, prevent clogging and so permit the free filtration or
drainage of the liquid from the ore or other compound under treatment. The
vessel may also be so constructed that an arrangement to hasten filtration by
suction may be adapted if desired and it may also be so constructed that operations
in it may be conducted under pressure, if pressure is deemed necessary. The
pulverised ore or other compound which has been placed in the vessel is saturated
with oxalic acid solution which for convenience is stored in a vessel and placed at a
higher level than the first mentioned vessel, such saturation being accomplished by
either upward or downward percolation or by both. When the ore or other
compound is completely saturated with the oxalic acid solution and shows strong
acid reaction, the superfluous liquid is preferably drawn off and liquid hypochlorite
of lime consisting of say 10 lbs. of hypochlorite to 100 gals. of water (which for
convenience is stored in a tank similarly placed) is caused to percolate by either
upward or downward filtration, or by both through the pulverized ore or other
compound, which has been saturated with the oxalic acid solution and this
percolation of the hypochlorite of lime solution is continued, until a strong persistent
chlorous odour begins to rise from the ore or other compound which is under
treatment. When this chlorous odour is distinctly and persistently discernable, the
flow of the hypochlorite of lime solution is arrested and time allowed for the various
reactions to take place and these may be hastened by causing the shaft in the first
mentioned tank to revolve. After the lapse of a sufficient period (generally about
one hour) the reactions are complete and the liquid matter is drawn off from the
powdered ore or other compound which has been under treatment by means of a
cock and run into a fourth tank so constructed that its contents may be heated
if desired by means of a steam coil or otherwise. After the liquid matter has been
run off the treated pulverized ore or compound is well washed with water, the
washing being effected by water being run into the first mentioned tank and by
causing the shaft in it to revolve. This water is next run off and added to the
liquid in the fourth tank.
The precipitation of the gold along with other matter is then effected by adding a
sufficiency of stannous chloride. This precipitation may be hastened and perfected
by heat, but heat is not necessary to be applied if a reasonable time is allowed for
complete precipitation say 12 hours. The precipitate is collected, washed with
water, dried, calcined or cupelled to get rid of foreign matter and the gold in it is
then melted and run into bars and will be found if the operations have been
properly conducted practically chemically pure.
The ore or other compound from which the said extraction of gold has been
made still contains its silver, which being in the form of chloride of silver has not
been dissolved out by either the chlorous solution or the water, but it is recoverable

page_text: by using any of the known solutions in which chloride of silver dissolves in and
then proceeding according to known means to procure it in its metallic condition.
It is manifest that the operation which has been described can be varied and
similar results obtained in a variety of ways, viz. :-The order of saturation with
the solutions may be reversed. The oxalic acid and the hypochlorite of lime one
or both may be mixed with the pulverized ore or other compound in a dry or
partially dry condition and the reactions necessary to be obtained by saturation
with water.
The drawing shows the apparatus I employ. A is the tank into which the
pulverized ore is introduced and B is a stirrer in it fixed on the axis B¹ which is
caused to slowly revolve. The bottom bar of the stirrer is armed with brushes C
acting upon the horsehair filter cloth D. E is a cock by which the liquid is
discharged into the tank F and G is a cock for emptying and cleaning. HH are
two tanks one for the oxalic acid and the other for the hypochlorite each being
provided with a stirrer H' and a cock and pipe J leading the liquid into the
tank A.
If upward filtration is desired the pipe J leads to the bottom of the tank A as
shewn in dotted lines. KK are test cocks.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. In obtaining gold and silver from ores and other compounds the use of
oxalic acid as a preliminary treatment to existing processes substantially as
described.
2. In obtaining gold and silver from ores and other compounds the use of oxalic
acid and a hypochlorite substantially as described.
3. Precipitating gold from solutions containing oxalates and chlorides by means
of stannous chloride substantially as described.
4. Obtaining gold and silver from ores and other compounds substantially as
described.
5. The apparatus for obtaining gold and silver from ores and other compounds
substantially as described and shown in the drawing.
Dated this 19th day of November 1894:
CARPMAEL & Co.,
Agents.