An Improved Method of Extracting Gold from the Various Auriferous Ores.
Year: 1888

page_text: Date of Application, 7th Aug., 1888
Complete Specification Left, 7th May, 1889-Accepted, 3rd Aug.,
1889
PROVISIONAL SPECIFICATION.
An Improved Method of Extracting Gold from the Various
Auriferous Ores.
I, CLAUDE THEODORE JAMES VAUTIN, of 23 Old Jewry, in the City of London,
and of St. Kilda, Victoria, Metallurgical Chemist, do hereby declare the nature of this
invention to be as follows:-
My invention relates to a method of dealing with gold contained in various auriferous
ores, especially sulphides or pyrites, by means of a combination of chlorination and
amalgamation whereby the ordinary method of roasting such pyrites is dispensed
with.
Now it is to a great extent proved that gold, contained in the various auriferous
sulphides or pyrites, is in a metallic state, although very finely divided and in most
cases coated so as to prevent the extraction by amalgamation if treated raw or
unroasted.
It is further necessary to roast ores containing sulphides before treatment by
chlorine, inasmuch as if the Chlorine is allowed to come into contact with unroasted
pyrites, little or no gold can be converted into a soluble chloride until all the sulphides
shall have been converted into ferric-oxide by the action of the chloride. It is
obvious that the oxidation of the sulphides by the use of chlorine is an expensive
process, and would on account of the cost render it useless for commercial purposes.
Now I have found that by a certain combination of chlorination and amalgamation,
I can dispense with the expense and delay caused in the roasting operation, for if
finely divided auriferous sulphides be submitted unroasted to the action of the
chlorine, the gold is not converted into soluble chloride, or if it is converted it is
immediately re-precipitated so long as any undecomposed sulphides remain, on the
other hand if the gold grains are cleaned by the partial action of chlorine upon the
unroasted auriferous sulphides and if the ore when so treated, is submitted in a separate
vessel to a system of amalgamation in which no sickening of the mercury as it is
technically called occurs, a very large percentage of the gold becomes amalgamated
and so recovered.
I am aware that it is not new either to submit unroasted or raw sulphides to the
action of chlorine or to treat raw or unroasted sulphides by the action of mercury for
amalgamation, but it is both new and useful to first chloridise unroasted sulphides in
one vessel and then amalgamate in another vessel.
Dated this 7th day of Amouct 1000
For FELL & WILDING,
R. A. Hoffmann,
1, Queen Victoria Street, London, E.C., Agents for the Applicant.
COMPLETE SPECIFICATION.
An Improved Method of Extraoting Gold from the Various
Auriferous Ores.
I, CLAUDE THEODORE JAMES VAUTIN, of 23 Old Jewry, in the City of London,
and St. Kilda, Victoria, Metallurgical Chemist, do hereby declare the nature of this
invention and in what manner the same is to be performed to be particularly described
and ascertained in and by the following statement :-
-
My invention relates to a method of dealing with gold contained in various
auriferous ores especially sulphides or pyrites by means of a combination of chlorina-
tion and amalgamation whereby the ordinary method of roasting such pyrites is
dispensed with.

page_text: Now it is to a great extent proved that gold contained in the various auriferous
sulphides or pyrites is in a metallic state, although very finely divided, and in most
cases coated so as to prevent the extraction by amalgamation if treated raw or unroasted.
It is further necessary to roast ores containing sulphides before treatment by
chlorine, inasmuch as if the chlorine is allowed to come into contact with unroasted
pyrites, little or no gold can be converted into a soluble chloride until all the pyrites
or sulphides shall. have been converted into oxide or oxides by the action of the
chlorine. It is obvious that the oxidation of the sulphides by the use of chlorine is
an expensive process, and would on account of the cost render it useless for commer-
*cial purposes.
.
Now I have found that by a certain combination of chlorination and amalgamation,
1 can dispense with the expense and delay caused in the roasting operation, for if
finely divided auriferous sulphides be submitted unroasted to the action of the chlorine,
the gold is not converted into soluble chloride, or if it is converted, it is immediately
re-precipitated so long as any undecomposed sulphides remain; on the other hand, if
the gold grains are cleaned by the partial action of chlorine upon the unroasted
auriferous sulphides, and if the ore, when so treated, is submitted in a separate or the
same vessel to a system of amalgamation in which no sickening of the mercury as it
is technically called occurs, a very large percentage of the gold becomes amalgamated
and so recovered.
I am aware that it is not new either to submit unroasted or raw sulphides to the
action of chlorine, or to treat raw or unroasted sulphides by the action of mercury
for amalgamation, but it is both new and useful to first chloridise unroasted sulphides
in one vessel and then amalgamate in another vessel.
In order to illustrate how I may bring my invention into practical effect I may
either employ closed vats or revolving barrels in which the chlorination or bromina-
tion of the ore takes place before introducing such ore into the amalgamating
machine; or I may first chlorinate the ore in a closed vessel (preferably a revolving
barrel) and when the ore has been sufficiently chlorinated or brominated, I introduce
into the said barrel mercury or known chemicals for the prevention of the sickening
of the mercury, in order to amalgamate the particles of gold and silver, the surfaces
of the said particles having been previously cleaned by the action of chlorine, bromine,
or equivalently iodine.
The barrel or vessel with which I effect this result may be constructed of steel,
iron, wood or other suitable material but preferably of steel or iron, in which case
it would be necessary to line the barrel with lead and wood, earthenware or glass,
so as to resist the action of the chlorine or bromine and expose no amalgamable
surface to the mercury.
I may introduce into this said vessel, if desirable, copper amalgamated strips or
plate for the gold and silver to attach itself to.
I construct such a barrel or vessel so that it may revolve round its own axis in a
horizontal line and I provide it with a suitable manhole for the introduction of the
ore and chemicals and with a suitable outlet for the withdrawal of the mercury after
the chlorination and subsequent amalgamation has been, effected..
Pyrites, in a finely powdered condition, are introduced into the vessel through the
man hole from any convenient hopper. The pyrites may have been previously
chlorinated in a separate vessel above, or may be in the raw state, in which latter case
a sufficient quantity of water is added (or which may have been placed in the vessel
previous to the introduction of the pyrites) together with a sufficient quantity of
sulphuric acid and chloride of lime or other substances from which chlorine may be
generated. The vessel is then closed and air, steam, or water pressure is applied
through a valve preferably placed in a hollow trunnion on which the vessel revolves.
The vessel is then set in motion and revolved for the space of an hour or less or as
long as may be necessary for the absorption of the chlorine. The mercury, is then
introduced and the barrel again revolved for such a space of time as may be neces--
sary to effect the amalgamation of the gold or silver in the particular. ore. under
treatment.
"

page_text: may equivalently use the barrel or vessel so that it shall revolve on its axis in a
vertical plane, the working of the process being similar to that before described.
In the event of my chlorinating in a separate vessel to that in which I subsequently
amalgamate, it is obvious that I may use any known amalgamator for the latter
purpose, and if desirable, pass the chlorinated pyrites over copper amalgamated
plates.
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 :-
The method of extracting gold from the various auriferous ores by the treatment of
the unroasted or raw sulphides or pyrites with chlorine, bromine or iodine, in
combination with the process of amalgamation of the same, substantially as described.
Dated this 7th day of May 1889.
FELL & WILDING,
1, Queen Victoria Street, London, E.C., Agents for the Applicant.