IMPROVEMENTS IN TREATING AURIFEROUS, ARGEN- TIFEROUS, OR OTHER METALLIC ORES.
Year: 1857

page_text: LETTERS PATENT to Edouard Primard, of Paris, (France,) Civil Engineer,
for the Invention of "IMPROVEMENTS IN TREATING AURIFEROUS, ARGEN-
TIFEROUS, OR OTHER METALLIC ORES.
Scaled the 5th January 1858, and dated the 11th July 1857.
PROVISIONAL SPECIFICATION left by the said Edouard Primard at the
Office of the Commissioners of Patents, with his Petition, on the
11th July 1857.
I, EDOUARD PRIMARD, of Paris, (France,) Civil Engineer, do hereby declare
the nature of the said Invention for "IMPROVEMENTS IN TREATING AURIFEROUS,
ARGENTIFEROUS, OR OTHER METALLIC ORES," to be as follows:-
The Invention relates to an improved method of reducing from their ores
gold, silver, and other metals, on which chlorine may sufficiently act. The
ores are heated in a suitable oven in which the same are arranged, in such
manner that by the introduction of water in the interior of the oven on the
ores, these latter are burst or split more or less, so as to cause them to be
more easily crushed and reduced to the state of a more or less finely divided
powder; or the ores may be heated in the oven, and burst afterwards by being
taken out of the same, and brought in contact at once with cold water. The
ores are then crushed in stampers of a cylindrical form, and provided with
suitable partitions; the stampers and pestels being of metal and of very

page_text: great power, the ores are thus reduced to a more or less fine powder, are
mixed with a suitable quantity of water, and in this state chlorine gas obtained
by any suitable means is caused to act on them in a closed vessel, whereby a
metallic solution is obtained from which the metal is afterwards precipitated,
after which the same is melted, and thus reduced to a duly metallic state.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Edouard Primard in the Great Seal Patent Office on the
11th January 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDOUARD
PRIMARD, of Paris (France), Civil Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eleventh day of July, in the year of our Lord
One thousand eight hundred and fifty-seven, in the twenty-first year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Edouard Primard, Her special licence that I, the said Edouard Primard,
my executors, administrators, and assigns, or such others as I, the said Edouard
Priuard, 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, usc, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN TREATING
AURIFEROUS, ARGENTIFEROUS, OR OTHER METALLIC ORES," upon the condition
(amongst others) that I, the said Edouard Primard, my exccutors or
administrators, by an instrument in writing under my, or their, or one of their
hands and seals, should particularly describe and ascertain the nature of the
said Invention, 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 Edouard Primard, do hereby declare the
nature of the 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:
The Invention relates to improved methods applicable principally to the
extraction of gold and silver from their ores, various parts of the Invention
being applicable also to the extraction of other metals from their ores,
Hitherto this separating, extracting, or reducing of gold and silver from their

page_text: ores was done, 1', by washing, after having previously caused the orcs to
be brought to a coarsely divided state by stamping or pounding them under
water, or by crushing the same while in the dry state between rollers or by
millstones; 2, by amalgamation with mercury; 8, by melting. By the
washing process all the metal concealed in the interior of the sand, and also
the fine particles carried off by the water are lost. By the amalgamating
process the mercury intimately unites with those particles only of the metal
which are sufficiently freed from their sandy covering. By the melting process
the evaporation gives rise to a considerable loss of metal. These threo
methods consequently, in comparison to the richness of the ore and the time
and capital they require, give but very trifling results, the great principle
having hitherto been overlooked that each particle of sand contains an appre-
ciable quantity of the precious metal intimately mixed therewith, and that
consequently, by gathering only those particles of the metal which offer them-
selves actually separated from the sand, by far the largest part of the metal
will be lost. It is from this reason that in my methods I principally have in
view to reduce to an almost impalpable powder the quartz, which, as being the
hardest and most difficult part of the ore, is in the old methods the least finely
divided, whereas the shistus and clayey parts are much easier reduced to a
very fine powder. In order, however, to cause the quartz more easily to bo
pulverized, I begin by submitting the same to an elevated temperature in a
closed kiln, so as to prevent any undue evaporation of the metals, and the
quartz having thus been brought to the required degree of heat, I cause a
small stream of water to be projected on the same.
In the annexed Drawing Fig. 1 represents an elevation, and Fig. 2, a plan
view of the kiln I make use of for this object. This kiln I prefer giving a
conical form; the same is constructed from fire-brick or any other suitable
fire-resisting material, and covered on the outside with a proper fire-resisting
cement; I prefer the kiln to be able of containing about 30 tons of ore at
cach operation. The kiln has an interior fire-place A, imbedded in the soil
X, Y, indicating the ground line; a are the fire bars; B is the door of the
fire-place of which C is the ash-pit; D is an opening for introducing the ore
in the interior of the kiln, after which this opening is hermetically closed, the
ore is heaped all round the firc-place in the kiln, and covered by a thin layer
of the shistus or other earth containing the precious metal. The kiln is then
fired, and the quartz having become sufficiently heated a small stream of
water is projected on the quartz, by means of a tube passing through the top
of the kiln, after which the quartz is extracted and submitted to the crushing
apparatus of which Fig. 3, represents a vertical longitudinal, and Fig. 4, a

page_text: vertical transverse section, and Fig. 5 a plan view. The samo consists of a
series of cast or wrought-iron stampers or pestles E, the lower ende of which
is rounded off, the concave bottom of the trough or cast-iron mortar F corre-
sponding nearly with the convexity of the pestles, each of which latter passes
through a cover G, with which each of the troughs is furnished, the pestles
are lifted up by suitable lever-arms H, fixed to a main shaft I, receiving motion
from any suitable prime mover. In order to obtain a perfect crushing, the
pestles should be very heavy, not weighing less than 1000 to 1200 lbs., and
act in succession and independantly of each other, so as to permit of stopping
the motion of one or more of them without interfering with the others. The
quartz having thus been brought to the state of an almost impalpable powder,
the same is mixed with the metal containing shistus or other carths, which
latter being much easier reduced to a fine powder, as the quartz may consc-
quently be pulverised in any suitable crushing or stamping apparatus. It
will be understood that previous to the introducing of the quartz or other
gangues in the kiln, they must be roughly crushed which I prefer doing by
means of square or rectangular cast-iron pestles acting in rectangular cast-
iron troughs. The quartz and the shistus or other earths having thus been
reduced, together or separately, to an almost impalpable powder, are now sub-
mitted together to the action of chlorine gas in the apparatus represented in the
Figs. 6, 7, 8. The same consists of a retort K, in which chlorine is evolved
by any of the known means, and carried by the pipe L into the receiver M,
the interior of which is lined with lead, and furnished with a perforated false
bottom m, on which the powder after having been mixed with a sufficient
quantity of boiling water is spread out. The pipe L opens in the false bottom
m, in order to cause the chlorine gas to pass through the ore spread out on the
said false bottom from where the gas is conducted by another pipe L', opening
in a similar manner in the false bottom m' of a second receiver M', from
where another pipe L again carries the gas to a third receiver, and so on for
a sufficient number of receivers which, if required, may be placed all round
the retort K, in the manner as shown by the plan view Fig. 8. Each of the
receivers is furnished at the top with a holo o, for introducing and withdraw-
ing the crushed ore, which hole is hermetically closed up during the introduc-
tion of the gas in the receiver; at the bottom each receiver has a pipe p
with stop-cock for drawing off the water collected below the false bottom.
The crushed ore before being introduced in the receivers is mixed with a
suflicient quantity of boiling water, so as to obtain a temperature of from 20
to 30° C. In each receiver a layer of quartz and sand is introduced between
the false an the real bottom, so as to serve as a filtering medium. The

page_text: chlorine having acted on the ore sufficiently long to effect the transformation
of the gold into chloride, the same is washed with hot water, which water
being collected the gold is precipitated therefrom in the ordinary manner by
sulfhydric acid or any other suitable means. The ore treated in this manner
still contains the silver, which latter is extracted by the following means:-
On the ore in each of the receivers M is laid a sufficient quantity of chloride
of sodium according to the silver contained in the ore. The receivers are
then connected with a steam boiler or generator in the manner as shown in
Fig. 7, in which Figure P represents the steam boiler from which a main
pipe Q conveys the steam to each of the receivers M, M', &c, by means of
dipping pipes q, q', &c. The steam having acted in this manner on the oro
for about two hours, the water condensed between the false and real bottoms
is drawn off by means of the pipes p, this water contains the silver, which
latter is precipitate therefrom, and the pure silver further obtained from this
precipitate by any suitable means.
Having thus described and particularly ascertained the nature of my
Invention, and the manner in which the same is or may be used or carried
into effect, I claim the apparatusses and modes of operating herein-before
described, in as far as they are to be employed for the extracting of gold and
silver or other metals from their ores.
In witness whereof, I, the said Edouard Primard, have hereunto set my
hand and seal, this Second day of January One thousand eight hun-
dred and fifty-eight.
5 Witness,
G. B. REPETTO.
EDOUARD PRIMARD. (L.S.)