AN IMPROVED MODE OF EXTRACTING METALS FROM THEIR ORES
Year: 1855

page_text: LETTERS PATENT to John Forrest, of Dears Place, Somers Town, in the
County of Middlesex, Mineralogist, for the Invention of "AN IMPROVED
Sealed the 15th April 1856, and dated the 16th October 1855.
PROVISIONAL SPECIFICATION left by the said John Forrest at the Office
of the Commissioners of Patents, with his Petition, on the 16th October
1855.
I, JOHN FORREST, of Dears Place, Somers. Town, in the County. of Middle-
sex, Mineralogist, do hereby declare the nature of the said Invention for
"AN IMPROVED MODE OF EXTRACTING METALS FROM THEIR ORES". to be as
follows:-
The chief object of this Invention is to extract the precious metals from
their ores by a more simple process than is at present employed. for that'
purpose. In carrying out this object, I reduce the ore to small pieces, and
immerse the same for a short time in an alkaline bath. I then remove the
broken pieces of ore from the bath, and subject them to the action of heat in
a retort or other suitably constructed furnace, and I thus effect the fusion of
the metal. Or I mix with the broken ore a dry flux composed of the com-
pounds of sodium or potassium, or the two combined, or other suitable fluxes;
and by means of furnace heat I extract the pure metal from the ore. By
continuing this heat, the pure metal may be run into a mass without the aid of
any subsequent operations, or the use of other media.

page_text: This process, besides enabling me to extract the gold in an expeditious and
economic way, avoids the waste of the precious metal, by the glaze which
forms on the broken pieces of ore preventing the dispersion of the minute
particles.
.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Forrest in the Great Seal Patent Office on the
16th April 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOIN
FORREST, of Dears Place, Somers Town, in the County of Middlesex,
Mineralogist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Sixteenth day of October, in the year of our Lord
One thousand eight hundred and fifty-five, in the nineteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said John Forrest, Her special license that I, the said John Forrest, my
executors, administrators, and assigns, or such others as I, the said John
Forrest, my executors, administrators, and assigns, should at any time agree
with, and no others, from time to time and at all times thereafter during
the term therein expressed, should and lawfully might make, use, exercise,
and vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "AN IMPROVED MODE OF
EXTRACTING METALS FROM THEIR ORES," upon the condition (amongst others) that
I, the said John Forrest, by an instrument in writing under my hand and
seal, should particularly describe and ascertain the nature of the said Inven-
tion, and in what manner the same was to be performed, and cause the same
to be filed in the Great Seal Patent Office within six calendar months next
and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said John Forrest, do hereby declare the
nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement (that is to say):
This Invention relates to the extraction of the precious metals from their
ores by a more simple and economical process than is at present employed for
.that purpose.
In carrying out this object, I reduce the ore to small pieces, and immerse
the same for a short time in a hot alkaline bath, in order that the ore may

page_text: absorb within its pores or fissures a portion of the alkaline solution. The
broken pieces of ore when saturated with the alkaline solution I remove from
the bath, and I then subject them to the action of a white heat in a muflle
retort, or other suitably constructed furnace. While under this heat the alkali
will become fused, and forming a flux, it will greatly facilitate the fusion of the
metallic matters contained in the ore, and the separation of the precious metals
from their combinations.
Another and most important part which this flux plays in the operation is
to cause the small particles of gold or silver to agglomerate in large beads on
the surface of the broken pieces of ore, and thus to prevent the loss of the
precious metals by: sublimation.
'
The ore having been subjected to a white heat sufficiently long to reduce
the gold to a pure metallic-state (which will in general take place in about
fifteen minutes, more or less, according to the quantity of ore under treatment),
is discharged from the muffle or furnace into cold water, whereby the ore is
rendered very fragile, and capable of being readily crushed and reduced to
powder. The precious metals may then be separated by any of the ordinary
washing or amalgamating processes.
The composition of the alkaline bath may vary, but I have found the follow-
ing to be cheap and efficient :-(1), American potash; two pounds dissolved in
water sufficient to cover the broken ore to be operated upon; or in lieu
thereof, (2) common soda; six pounds dissolved in the like quantity of water
before indicated; or, lastly, (3), a mixture of one pound of American potash
with three pounds of common soda dissolved in water, as above indicated.
When operating upon gold or silver bearing ores which contain in large
quantity either iron, copper, or arsenic, I prefer to modify my process some-
what; that is, instead of immersing the ore in a hot alkaline bath, I place
the broken ore in the furnace, (preferring to operate upon, say, half a ton at a
time rather than on a larger quantity,) and strew over it or mix with it a dry
flux. I then raise the temperature of the furnace, as before described, to a
white beat, and extract the precious metal in a pure state from the ore. By
continuing this heat, the pure metal (if the ore under operation is very rich)
may be run into a mass, thus rendering the crushing, washing, or amalgamating
processes unnecessary. When the fusing operation is arrested at the stage at
which the ore is discharged into water, the gold or silver will be found in the
form of beads of various sizes studding the surface of the ore, which is
covered with a glaze, that insures the adhesion of the gold or silver beads to
the ore, and which glaze prevents (as above mentioned) the sublimation of the
precious metals. The dry flux which I prefer to employ (the quantity of ore

page_text: under operation being, say, half a ton,) is a mixture of nitrate of potash-one
pound, carbonate or borate of soda one pound, and common soda eight pounds.
I do not, however, confine myself to these proportions, or indeed to the com-
bined use of these materials, as the object I have in view is simply to obtain a
cheap and efficient flux, which will also by glazing the ore prevent the loss of
the gold and silver by sublimation.
Having now set forth the nature and object of my Invention of "An Improved
Mode of Extracting Metals from their Ores," and explained the manner of
carrying the same into effect, I wish it to be understood that I claim the
glazing of gold and silver bearing ores as herein described, for the purpose of
preventing the loss of the gold and silver by sublimation when exposed to
-furnace heat.
In witness whereof, I, the said John Forrest, have hereunto set my
band and seal, the Sixteenth day of April, in the year of our Lord
One thousand eight hundred and fifty-six.
Witness,
J. W. MOFFATT,
66, Chancery Lane.
JOHN FORREST. (L.S.)