The Placer herald., 1865-12-16
Frofh the S. F. Mining and Scientific Press
Gold-bearing Sulphurets and their Reduc.
ton.
BY JOHN SCOTT, NErALLURGICAL CHEMIST.

ent time in the mining community of Cali.
fornia, concerning the introduction of an ef-
tectual and economical method of extracting
the precious metal from the large quantities
OF god,bearing SUI phurets of iron, which are
so extensively found in various parts of this
State, and which are almost valueless TO
their owners because no really practical and
cheap 'neIhod of working them has as yet
been successfully carried into effect have
thought the following remarks in relation TO
their treatment might be of sufficient interest
to your readers to secure place in the col
ums of the Press. Having conducted nu,
merous experiments during the last eight
years on that class cf minerals. for the 'pur.
pose of arriving at a solution of the problem
OF their economical working, | shall enumer.
ate some OF them, and endeavor to point out
what | consider to be an effectual method
for the purpose, describing first process of
my own invention. which gives the desired
result, but which was abandoned by me on
account OF the great expense attending il,
and the tardiness of the operation. By
means of this process the whole of the pyri.
tous matter was converted into magnetic
oxide of iron, the precious metals being left
in a free" state, capable of being extracted
by ANA ganalion, none being lost during
the operation by volatil;zalion or otherwise
| took the sui phure's, mixed them with Car.
bon and placed them in appropriate vessels,
excluding atmospheric oxygen, while a cur
rent of steam was made to act on the mix
ture, it being maintained at bright red
heat. The use of the carbon was to render
The mass permeabIe by vapor and prevent
fusion of the proto sulphurets; the hydrogen
Of the decomposed steam united with the
sulphur of the mineral, and was carried off
principally in the Stale Of sui phuretted by.
drogen, while the oxygen united with the
iron, forming an oxide having the formula
F.3 o.
The common method adopted for desul.
pburizing the mineral is to roas, it, in
finely divided state, with constant stirring,
on sole or reverberatory furnace, with the
assistance Of heat and atmospheric oxygen,
until it be completely peroxidsed. By
means of this method the precious metals
are "treed," when contained in bisu|phde
OF iron, and may be extracted hy we'll known
methods, but unfortunately (this being an
almost universally admitted fact, from TWEEN
ly to eighty per cent. of The precious metals,
especially gold, is carried off. mechanically,
in fine state OF division, along with the
dense fumes Of sulphurous acid gas which
are generated during the decomposition of
the mineral. and which is lost, unless some
means be employed for its collection.
Another method is the "Chlorinalion pro-
cess" which demands, as in the former,
similar oxidation, and hence being subject to
the same loss Of gold previous to the treat.
menl of the mass by chlorine and precipita.
ton of the gold tv proto-suI phate of iron.
The gold by this process is obtained nearly
pure, in the slate OF fine brown powder,
which is afterwards melted into ingos, while
the silver that is associated with the gold is
lost, unless it be afterwards recovered by
treatment with some liquid capable of dis.
solving the chloride of silver formed, which
would be an expensive process, when the ar
genliferous metal exists only in small guam
titles in the alloy contained in the mineral
Several new "invenlions" have been made
lately in the shape of furnaces, to do the
work of desu phurizing and oxidizing the
suphures; but am not aware that any
have yet answered the expectations Of the
inventors. Among them | may mention
"1he Gold and Silver Separating Company's
Furnace" (Dr. Hagan'S), the performance of
which | was requested to examine, in my
professional capacity, the result OF which
may be interesting 10 many OF your readers,
and AS have the permission OF the party
for whom | made the examination to make
it public, will do so.
The object WAS to ascertain If the mineral
operated on (bi SUI phide Of iron) was COM
pIeteIy desuIphurized; if not, to what extent;
If any loss of gold occurred during the
treatment; the amount extracted by amaIga
nation, and the state Of the refuse after
amalgamarion. Samples were furnished me
for the purpose. The mineral had been
treated in Jumps; heat, atmospheric oxygen
and superhea,ed steam being used. The
mineral WAS thus treated, as vas Informed,
during tor'y-eight hours. The result Of my
examinations was as follows:
FIRST - Assay of the crude sulphurets:
Gold $39l.72; Silver $376=S395.4S per
ton.
Second-Analysis Of the crude sulphurets:
Gold O,O65; Silver q OlO; Iron $3.50; Sui
pbur SO $40; Silica (quarlz) 26 73O.
Third-Assay of the mass after treatment:
Gold 1920 so; Silver $3O2=$33252 per
ton.
DISCRIMINATION Of the treated mass
for sulphur only which was found to exist
(partly in bi.suIpbide Of iron and partly in
magnetic sulpbure,) to the extent of 1890
per cent. -,
Fhh-Assay of the bullion extracted by
amaIgamaion, its weight was l.47 ounces
Gold s36 fine, value $25 40; Silver l3l fine,
value so 25; full value $25 65.
Sixth assay Of the tSilings $l4el2 per
ton.
From which conclude that nearly six
teen per cent. Of the precious metals was lost
during the treatment; that the mineral was
desuphurized to the extent OF hfiy-hve per