ores or compounds Containing the same.
Year: 1886

page_text: Date of Application, 13th Oct., 1886.
Complete Left, 13th Aug., 1887.
Complete Accepted, 11th Oct., 1887.
ores or compounds Containing the same.
I, ALEXANDER PARKES, of 8 Chancellor Road, Dulwich, in the County of Surrey,
Gentleman, do hereby declare the nature of this invention to be as follows:-
This invention relates to the treatment of certain kinds of ores or compounds, which
contain gold, and frequently silver and other valuable metals, for the purpose of
extracting such metal or metals therefrom.
In treating silicious ores, I crush or granulate the ore and fuse the same in a
reverbatory or other suitable furnace with fluxing matters containing baryta, lime,
fluor-spar, cryolite, caustic soda, chloride, silicate or carbonate of soda. The particular
kind of flux most suitable for the purpose varies with the character of the ore under
treatment, but may be readily selected by those skilled in metallurgical art. The
mixture of ore and flux having been converted in the furnace to a perfectly fused mass,
I add thereto metallic lead in a granulated state, or litharge, or other oxide of lead
or carbonate of lead. When the ore is poor in lead, I may add thereto copper or tin,
or the oxidised compounds of copper or tin, with sufficient carbon to reduce the lead
or other metals in combination with the precious metals. When the ore contains
iron (such, for example, as that obtained from the Mount Morgan Mines of Queens-
land) the precious and other metals may be collected by fusion without the addition
of lead; a small quantity of carbon being used with the flux with a view to reducing
a sufficient quantity of the iron to form with the gold and other metals a metallic
mass of a character adapted for subsequent economical treatment. In some instances,
particularly where the ores are free from lead, I add copper or tin, or the oxidised
compounds of copper or tin, to form or assist in forming a metallic medium in which
the precious metals are concentrated. By the use of the above named fluxing agents,
I obtain a practically perfect reduction of all the gold (and silver, if any) contained
in the ore; the slag resulting being practically free from the precious metals.
The compound of auriferous lead resulting from the above described process may
be cupelled and the gold separated without employing mercury. If the compound
contain gold and silver, the precious metals may be separated from the lead by means
iD.
171

page_text: of metallic zinc on what is known as Parkes's desilverising process. If the compound
contain copper or tin, either naturally or by addition in the process of reduction, the
same may be separated and recovered by the methods hitherto generally practised, or
by electrolysis.
When operating upon refractory ores of the sulphide class (such, for example, as that
obtained from the Ravenswood Mines of Queensland) and which usually contain gold,
silver, copper and other metals, I crush or granulate the ore and melt it in a furnace
as before described, but in conjunction with fluxes composed of the alkaline or earthy
sulphates or chlorides, and containing carbon or to which carbon is added. To the
mixture of ore and flux is added lead or oxidised compounds of lead. When the ore
does not contain sufficient lead to combine with and collect the gold (and silver, if
any) contained in the ore, sulphide of lead may be added with the object of collecting,
chiefly in the form of sulphides, all the precious and other metals sought to be
recovered. These completely separate from the slag; and, the latter having been
removed, the sulphide compound or regulus whilst hot is sprinkled with water which
causes the mass to disintegrate and resolve itself into a fine powder. Although
convenient and in some respects advantageous, it is not an essential feature of my
invention that the regulus should be thus treated whilst in a heated state.
By the above described means, the metallic sulphides are concentrated in a mass
of comparatively small bulk. The product is thereupon calcined, and the precious
and other metals are extracted by any of the ordinary methods. Previous to cal-
cination, it is sometimes advantageous to wash the regulus with water with the object
of removing soluble impurities.
Dated this 11th day of October 1886

page_text: Ores or Compounds Containing the same.
I, ALEXANDER PARKES, of 8, Chancellor Road, Dulwich, in the County of Surrey,
Gentleman, 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 :—
This invention relates to the treatment of certain kinds of ores or compounds for
the extraction of the gold, silver and other metals contained therein by means of an
economical and expeditious process which enables practically the whole of the precious
metals to be separated, and whereby the usual preliminary operation of calcining the
ore is dispensed with. The processes of amalgamation and chlorination may also be
avoided.
In treating silicious ores, which frequently contain silver, copper and other metals
in addition to gold, I crush or granulate the ore and melt it in a reverberatory or
other suitable furnace with fluxing matters containing caustic lime or limestone and
caustic soda or silicate of soda. The mixture of ore and flux having been converted
in the furnace to a perfectly fused mass, I add thereto metallic lead, by preference in
a granulated state, or litharge or other oxide of lead or carbonate of lead. When the
ore is poor in lead, I may add thereto (instead of lead) copper or tin or the oxidised
compounds of copper or tin, with sufficient carbon to reduce the lead or other metals
in combination with the precious metals. When the ore contains iron (as is the case,
for example, with that obtained from the Mount Morgan Mines of Queensland), the
precious and other metals may be collected without the addition of lead; a small
quantity of carbon being used with the flux with a view to reducing a sufficient
quantity of the iron to form with the gold and other metals a metallic mass of a
character adapted for subsequent economical treatment. In some instances, particularly
where the ores are free from lead, I prefer to add iron, copper or tin, or the oxidised
compounds of iron, copper or tin, in conjunction with carbon, to form or assist in
forming a metallic medium in which the precious metals are concentrated. By the
use of the above named fluxing and other agents, I obtain a practically perfect
reduction of all the gold (and silver, if any) contained in the ore; the slag resulting
being practically free from the precious metals.
The compound of auriferous lead resulting from the above described process may
be cupelled, and the gold separated without employing mercury. If the metallic
compound contain gold and silver, the precious metals may be separated from the lead
by means of metallic zinc on what is known as "Parkes's desilverising process."
If the metallic compound contain copper or tin, either naturally or by addition in the

page_text: process of reduction, the same may be separated and recovered by the methods hitherto
generally practised or by electrolysis.
In applying my improved process to auriferous ores which are essentially silicious
and non-sulphurous, the fluxing materials I prefer to employ consist of caustic lime
and caustic soda in combination, the same being used in conjunction with carbon. No
appreciable loss of gold or silver takes place either in the furnace or in the slag. In
operating upon such ores, for example, as are obtained from the Mount Morgan Mines
of Queensland, I employ with each ton of ore from 3 to 5 hundredweight of caustic
lime (by preference), 1 to 14 hundredweight of caustic soda or silicate of soda, together
with from to 1 hundredweight of carbon. To these is added from 1 to 3 hundred-
weight of lead or oxidised compounds of lead; or there may be substituted herefor
from 1 to 2 hundredweight of a mixture of silicate of lead and soda in equal pro-
portions. The above proportions will work satisfactorily with other ores of the silicious
and non-sulphurous class; though in each case actual trial and experience may
enable the proportions given above to be somewhat varied with advantage.
By the means described, I am enabled to form a bath of alloy in which the gold
and silver are collected and from which the slag can be readily separated. If the ore
contain copper or other reducible metal, such metal or metals will be similarly
collected in the alloy; and if deemed of sufficient value, may be recovered therefrom
by electrolysis or other known process.
In treating refractory ores of the sulphide class, I crush or granulate the ore, as
before described, and melt it in a reverberatory or other suitable furnace with fluxes
composed of caustic lime or limestone in conjunction with caustic soda, or silicate of
soda, or sulphur compounds of soda, such as sulphate and bisulphate, and containing
carbon or to which carbon is added. To the mixture of ore and flux is added lead,
or oxidized or sulphur compounds of lead, with the object of collecting all the precious
and other metals sought to be recovered. These completely separate from the slag ;
and the latter having been removed, a metallic compound is obtained in a condition
suitable for treatment by what is known as "Parkes's desilverising process," or by
other known methods for separating the gold and other metals contained in such
compound.
In some instances, the ore in its natural state contains sufficient lead to render the
addition, as above mentioned, of lead or oxidised or sulphur compounds of lead
unnecessary; in which case, a sufficient quantity of the lead naturally contained in
the ore is reduced and combines with and serves to collect the gold (and silver, if any)
contained in the ore.
Instead of adding lead in the furnace as above described, a regulus may be obtained
as the result of the process of smelting the mixture of ore and flux, and this regulus
may be treated with lead or the compounds of lead before mentioned.
The regulus obtained as the result of smelting sulphide ores with the compound
flux of the kind herein before specified possesses the peculiar property or tendency to
disintegrate and resolve itself into a fine powder by mere exposure for a few hours
to the atmosphere. This effect, which resembles that to which quicklime is subject,
may be expedited by sprinkling the regulus, whilst hot, with water. In such finely
divided state, the regulus is specially adapted for treatment with lead or by other
known methods for separating the gold and other metals contained therein; as, for
example, by calcination and chlorination. Furthermore, the metallic sulphides being
collected in a concentrated mass, the quantity of material or regulus requiring further
treatment is of comparatively small bulk.
In applying my improved process, by way of example, to ores such as are obtained
from the Ravenswood Mines of Queensland, I employ, for each ton of such ore,
3 to 4 hundredweight of caustic lime (by preference) in combination with either
1 hundredweight of caustic soda, or the same quantity of sulphate or bisulphate of
soda, or half that quantity of silicate of soda; from to 1 hundredweight of carbon
being added. If the ore be very refractory, a small proportion of oxide of iron may
with advantage be employed to assist the fusion of the earthy matters.
I regard it not merely as unnecessary but as undesirable that the ore should be

page_text: subjected in the first instance to calcination for the purpose of driving off the sulphur
contained therein. I have found that without calcining the ore, the metals reduced
separate very perfectly from the slag, and that the latter is left remarkably free of
the precious metals. Furthermore, by my improved process, the use both of amalga-
mation and of chlorination may be dispensed with, an improved result being at the
same time attained.
Instead of a reverberatory furnace, a cupola or blast-furnace may be employed for
melting the ore. Before being placed in the furnace, the ore may with advantage be
crushed to a moderate size; but the usual operation of stamping or grinding the same
to a fine powder is rendered unnecessary.
I regard as a characteristic feature of my invention the use of caustic lime and
caustic soda in combination as fluxing materials, loss of gold and silver being thereby
prevented. These agents, when used in suitable proportions such as I have indicated,
react upon one another in such a manner as to produce great fluidity and to permit
of a given quantity of ore being treated with a far smaller quantity of flux than by
any laboratory or other process with which I am acquainted, my improved process
being thereby rendered commercially practicable. In cases where carbonate of baryta,
fluor-spar or cryolite are readily procurable, they may be added with advantage in
small quantities to the mixture of lime and soda; the fluor-spar being specially useful
in highly silicious ores as it renders the slag very fluid, in like manner as oxide of
iron acts when the ore is highly aluminous. Carbonate or nitrate of soda may also
be used when procurable at a sufficiently cheap rate.
Having thus particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, I would have it known that I do
not confine myself to the exact proportions specified as suitable for each of the
principal classes of ore, inasmuch as the variations in the physical and chemical
characteristics of ores will suggest modifications in individual cases, but I claim :-
1st. The improved process of treating auriferous ores of the silicious class, whether
sulphurous or non-sulphurous, for the extraction of the gold and other metals contained
therein, by fusing the ore in a suitable furnace with fluxes compounded of lime and
soda substantially in the proportions herein respectively specified for each class of
ore, adding thereto lead or oxidised compounds of lead and producing a metallic
compound adapted for treatment by known methods for the separation of the gold
and other metals contained therein.
2ndly. For treating auriferous ores of the silicious and non-sulphurous class and
containing iron, the modification of the process referred to in the first claiming clause,
substantially as herein set forth; and whereby the use of lead for forming a metallic
medium for collecting the precious metals is dispensed with, and a portion of the iron
contained in the ore is employed for the purpose, carbon being added (with or without
oxide of iron) for reducing the said metals.
3rdly. For treating auriferous ores of the silicious and non-sulphurous class,
particularly such as are free from lead, the further modification of the process
referred to in the first claiming clause, substantially as herein set forth; and whereby
iron, copper or tin, or the oxidised compounds of iron, copper or tin, are introduced
to the furnace and furnish or assist in forming a metallic medium for collecting the
precious metals.
4thly. For treating auriferous ores of the sulphide class, the modification of the
process referred to in the first claiming clause, substantially as herein set forth; and
consisting of fusing the ore in a suitable furnace with fluxes compounded of lime
and soda, whereby a regulus having a natural tendency to disintegrate is produced,
which may be treated with lead or by other known methods for the separation of the
gold and other metals contained therein.
5thly. As fluxing substances for use in fusing auriferous ores of the silicious and
non-sulphurous class, the combination, substantially in the proportions herein set
forth, of caustic lime or limestone with caustic soda or silicate or carbonate of soda,
the same being employed in conjunction with carbon.

page_text: 6thly. As fluxing substances for use in fusing auriferous ores of the sulphide class,
the combination, substantially in the proportions herein set forth, of caustic lime or
limestone with caustic soda or nitrate silicate or carbonate of soda or sulphur compounds
of soda.
7thly. In the reduction of auriferous ores of the sulphide class, producing a regulus
having a natural tendency to disintegrate and to assume a condition specially adapted
for expeditious and economical treatment by known methods for the separation of
the gold and other.metals contained in such regulus.
Dated this 19th day of August 1007