Gold Hill daily news. [volume] (Gold Hill, N.T. [Nev.]) 1863-1882, 1865-12-05

stones, or other suitable apparatus, and
brought to the condition Of an impalpabie
powder, when it is ready for the a~malgamat-
ing process. 3D. 49,
This is performed in casks, arranged in a
horizontal position in rows, each turning on
a shaft which passes through its axis. These
casks are Of various sizes, from q capacity to
receive 1000 pounds Of ore, to that Of 5000
pounds, as may be seen at the new French
Mill, and are provided in mostcases with iron
ends-when charged with the sifted ore and
about thirty per cent. Of water; about elgnt
per cent. Of metallic iron is introduced, for
the purpose Of reducing the chloride to the
condition of metallic silver, when it amalga.
mates with the mercury. The casks, being
charged, are set to reyolve for an hour and a
half or two hours, till the ore-powder and
water become an uniform pulp. The mer-
curry is then introduced, and the casks again
put in motion, ut tho rate OF about twenty
revolutions per minute, for fourteen or slx-
teen hours.
During tho rotation the temperature rises
considerably, so that even in Winter it some
times stands as high as l04 dogs. Fahrenheit.
In this operation the chloride Of silver is
decomposed by the metallic iron, and the
liberated silver a~malgamated BY the mercury.
This matter is greatly facilitated and expe-
dited by the presence Of an excess Of salt in
the water, which, although taking no direct
chemical action on the already chlorinized
silver, increases the intensity OF the reducing
power Of the metallic iron, by its predispos-
ing or electro-chemical agency, just rs the
yoltaic pile of copper and silver IL rendered
active BY a solution Of salt. ..
The fact is well known and appreciated by
the amalgamators Of Chile, who always used
salt in the reduction Of their ores OF native
chloride of silver with advantage, both as
regards time and produce. As soon rs the
amalgamation is supposed to be complete,
the casks are filled with water and set revolv-
ing slowly (about six or eight times in n min
ute), whereby, in the course Of an hour, the
greater portion Of the amalSam will have col
lected at the bottom, and, in consequence Of
| the dilution, n portion OF the chloride Of sill.
YER held in solution By the salt will fall down
and become decomposcd and amalgamated.
| The amalgam is then drawn oil into suitable
vessels, aud the remaining portions Of the
casks run of into n vessel similar to the sep
arators of Nevada, when the remaining por-
ton Of the amalgum is recovered. The ANAL
gam is then strained and distilled in the
usual manner, previous TO the melting OF the
| silver into bars.
The fourth process, which is very extern
sively practiced in England, is hat Of smelt-
ing the refractory ores Of silver with argen-
~tiferous galena. In this operation the lead
ore is first crushed and concentrated BY
washing, up to sixty or seventy per cent. Of
lead. It is then dried on the top OF the re-
yerbatory furnace. which in its most improved
form is furnished with two hearths, one
above the other, the dried ore is passed
through n door in the roof Of the upper
hearth, where it undergoes a roasting and
dcsulphurizing, at n temperature sufficiently
low to avoid fusing the sulphide of lead.
When this has been accomplished, 1t IS
raked through an aperture into the hearth
below, where it is kept some hours at n red
heat it comes out in a verified condition,
and contains about ninety per cent. of lead.
The roasted ore is then broken up and mixed
with limestone and small coal, metallic iron,
and sometimes soda ash-the mixture thrown
into the reducing furnace (Which is on the
cmpola principles, similar 10 those used in
the iron foundries, with alternate layers Of
coal. When the operation is completed. the
slugs are nearly free from lead and silver,
and n mattee remains with the last portion,
which contains about twenty per cent. OF
lead. This is broken up and returned to the
furnace with the next charge.
The poor and refractory ores OF silver,
such as tailingS, are very advantageously
treated in this process. They are first to be
mixed with sufficient clay TO give consistency
to the mass to enable It to be nodded into
small bricks. These are dried in the air till
they will bear handling, and then introduced
into the reducing furnace when ut its full
heat; the silver is taken up BY the lead with
all the accuracy OF an ordinary assay, and Is
afterwards separated By what is known as
Pattinson's process for desilvcrizing lead.
Tb., 1no.oKtNn 20 Nnrfnrpnj IN fynlyn IN
twenty. -four cast iron pans, five TO six feet in
diameter, and three to three and n half feet
deep, set in two rows, back to back, in a
range Of brickwork, each pan being furnished
with its own furnace. The argentferouS
lead is introduced into the pans Mt each eX-
tremity Of the rangc, and when melted, the
hrc drawn and contents permitted to cool.
As it does so the lead solidifcs, as small
granular crystals from the sides Of the pan
toward the center. When about one.haif
the quantity has solicited, it is quickly tished
out with large iron ladies' perforated so as to
allow the fluid portion Of the lead, which re-
tains the silver and flows back into the PAM.
and transferred to the next pan, where 1t IN
dergoes the same process Of melting, cooling
and fishing, into the next pan, and so on till
the solid hshed lead is found to be free from
silver, which is generally accomplished by
the time it has reached the sixth pan, all the
silver remaining with the fluid lead left in
the different pans.
Fresh silver lead is introduced into the first
pan after each fishing, and the silver is thus
concentrated in the fluid lead OF each pan
without increasing the bulk. This conccn-
tration goes on till it approaches $50 ounces
of silver to the ton Of lead. When the con-
GLIDING operations are performed by mixing
the different fluid portions, and gradually
concentrating by repeated fshings in one
small pan when the richness has arrived
at $50 ounces to the ton (Which it should not
be allowed to exceed) it is conveyed into a
small pan set in the same brickwork with
the cupclling furnace, and fed into tho cupel
BY n ladle through 4 channel Of communica-
ton as reQuired-the cupel is usually OF an
oval shape, two feet long by fifteen inches
wide and three inches thick-it works of its
| charge to saturation, and furnishes the plate
Of silver in about twenty hours. BY this
process lead containing but four ounces OF
silver to the ton is prOftably worked-the
loss Of lead does not exceed two per cent,
while its quality Il. e., malleability) is greatly
| improved BY the extraction Of the silver, de-
silverized lead being worth So per ton more
than that which contains silver enough to
| contaminate, but insufficient to pay for eS-
traction.
When silver is found to exist in paying
quantities in copper ores, which is often the
case with the gray or antimonial ore Of cop.
per, the calcined ore is mixed with lead or
lead ores and fused or calcined, and the re-
sulting products are either liquidated TO
sweat out the silver, or cupelled. In liqui.
dation the copper is run into pigs (called
liquidation cakes) and kept above a red heat
for two or three days the lead first melts
and flows in drops into cast iron troughs,
carrying with it the silver which is after
wards obtained by cupellation.
The fifth and last method of reduction to
which | shall draw your attention is that
known as the brine process, by which the
chloride Of silver formed by calcining and
chlorinizing in the reverbatory furnace, is
dissolved out Of tho other furnace products
by means Of a hot concentrated solution Of
salt, and the metallic silver obtained by pre-
cipitation with metallic copper.
This process was first introduced in Ger
many some years ago, but from some defects
and obstacles in working it ton the large scale,
it was for Il long time regarded BY practical
men us a failure, until after a series Of elabo-
rate and expensive experiments, said to have
cost over $780,, 900, it was brought to perfec-
ton and is now in successful operation in the