Improvements in Gold Extracting Processes, and Apparatus Communicated therefor. POUR L'EXTRACTION by LA SOCIÉTÉ ET INTÉGRA ECONOM PROCÉD Extractor
Year: 1895

page_text: his Print is in accordance with the Original Specification as it stands after
Amendment (under Section 11 of the Patents, &c., Act, 1883), as required by
the decision of the Chief Examiner of the 5th day of December 1896. .
Date of Application, 24th Aug., 1895
Complete Specification Left, 23rd May, 1896-Accepted, 27th June, 1896
PROVISIONAL SPECIFICATION.
Improvements in Gold Extracting Processes, and Apparatus
Communicated
therefor.
POUR L'EXTRACTION
by LA SOCIÉTÉ
ET
INTÉGRALE
ECONOMIQUE DE L'OR, PROCÉDÉ DE RIGAUD, of 16, Rue Drouot, Paris,
in the Republic of France, Gold Extractors.
I, WILLIAM PHILLIPS THOMPSON F.C.S. M.I.M.E. of The Agency for
Foreign Patent Solicitors 6, Lord Street, Liverpool and 6, Bank Street
Manchester both in the County of Lancaster, 118, New Street, Birmingham in
the County of Warwick and 31 High Holborn in the County of Middlesex,
Civil Engineer do hereby declare the nature of this invention to be as
follows:-
:-
This invention has for its object an improved process for extracting gold from its
ore, allowing the extraction of the whole of the metal to be effected at a cost much
below that of the most improved processes at present employed.
This process consists in treating the gold ore with a powerful solvent which is
formed by the combination of sulphur and chlorine forming a cloride of
sulphur SC, which is, according to the remarkable works of Mr. Isambert, the only
clearly defined chloride of sulphur.
:
Although chlorine constitutes one of the elements of the solvent which is.
employed, this improved process has no analogy with the processes based on the
use of free chlorine or nascent chlorine, and particularly with the very improved
method of Plattner, seeing that chlorine does not act in this form in
process.
our'
It may also be pointed out that as there exists only a single clearly defined chloride
of sulphur S.Cl, it is easy to deduce therefrom that all the chlorides of sulphur only
differ from one another by the greater or less saturation of their solution with
chlorine. This process for the economic treatment of gold ore is based on this
circumstance.
This process consists in introducing, into a suitable closed receptacle, ore mixed
with water in sufficient quantity to form a liquid mud.
.
· Ore crushed, and sieved in a No. 30 sieve generally requires 10 to 15% of water
to bring it to this condition, but it is evident that more water will be required
according as the ore is more finely pulverised. When this has been done it is slightly
warmed, and the solution of chloride of sulphur super-saturated with chlorine, is.
immediately introduced.
I

page_text: The reaction is a complex one, and becomes more complex according as there are
more metals present in the ore. In the simplest case, that is to say in an alluvial
ore, pan dirt, or native gold contained in a quartz gangue, there takes place simply
a contact of the combined solvents with the precious metal which is dissolved almost
instantaneously and entirely. The solution of gold mingles with the water without
being precipitated. A little sulphuretted hydrogen is formed as a result of the
small quantity of iron which the quartz contains, and a little sulphate of lime which
remains insoluble. It is only then necessary in this case to filter and wash, in order
to collect the entire gold contained in the ore. But it is not always alluvial- or
quartz-mud which is to be treated, and then the reaction is more complex without the
treatment being more complicated.
A certain quantity of metals previously existing in the ore in the form of sulphides
are first separated from their compounds, and pass into the condition of chlorides,
some soluble, others (such as silver, quicksilver and the like) insoluble. But there is
formed at the same time sulphuric acid, and sulphuretted hydrogen, the former
precipitates the insoluble sulphates, the latter reconverts a part of the others
into sulphides, whilst owing to the heat which these chemical actions cause,
the sulphur released combines directly with the magnesium, copper, iron,
lead, cadmium and bismuth which have escaped the action of the sulphuretted
hydrogen, thus releasing and allowing to pass into the condition of chloride,
all the precious metal which these other various metals in their former condition
retained.
When the gold ore does not contain either antimony zinc, or tin, as is very
frequently the case, the result of the reaction is found to be identical and similar
in all points to the treatment of quartz, alluvial ores and the like. When on the
other band these three metals are found in combination (a case almost unknown)
with gold ore, the use of this improved solvent must be dispensed with for the
moment.
Finally if only one of these metals be combined with the gold ore, it
passes with
it into the chloride solution, and then it only requires to be treated by one of the
suitable separating methods described in any treatise on chemistry.
A rapid and simple method of separation in the case where two of these metals are
combined with the gold ore will now be described.
When all the parts of the gold ore have been brought in direct contact with the
combination of sulphur and chlorine employed, the whole of the gold which these
ores contain either in the form of native gold, or of sulphide, or of oxide, is
transformed into soluble chloride of gold, and it suffices to collect the whole of this
solution in order to extract the whole of the gold from its ore.
This is done by washing it in pure water, and in order to avoid having to
precipitate small quantities of gold in. solution, in a sufficiently large quantity of'
water, such washing water is then collected in a large vat or tank where it is,
allowed to deposit its metallic gold under the action of air alone, and of the
organic elements which such water always contains in sufficient quantity to produce
sufficiently rapidly this result. The same washing water under these conditions
may serve a large number of times, which is a great advantage for gold-mining
operations where the scarcity of water creates real and even unsurmountable
difficulties.
The part of the coloured but limpid solvent which, after filtration, contains the
gold except what the washing water has carried away, is treated with sulphate of
iron, which precipitates the precious metal in a metallic condition. If care be'
taken to only employ for the precipitation, the quantity of ferric salt actually.
necessary according to the percentage of precious metal in the ore, this same solvent
after having given up the gold contained in it, may serve again and again for the
further treatment of fresh ore, but in this case it is better not to carry out the
precipitation before the solvent is almost saturated with gold, that is to say contains
about half its weight in gold.
As already stated this solvent may be employed in two different ways, one"

page_text: which may be called the slow process although it is still incomparably quicker
than the most recently known one, and the other which may be called the rapid
process, because the whole operation may be accomplished in a few hours (crushing
the ore, dissoiving the gold, precipitation and combination of the precipitate into
an ingot of metal).
Any suitable apparatus consisting of a closed vessel made of enamelled cast iron,
or other suitable material capable of resisting the corrosive action of the solvent,
may be employed for carrying out this so called rapid process. The apparatus
may be fixed or movable, and comprises an agitator, which enables the material to
be imashed so as to cause it to be thoroughly brought in contact with the solvent.
The apparatus must be capable of being heated by steam or by an open fire. It
must however be noted that this heating is not indispensable, and especially that
it need not be prolonged. It only serves to hasten the commencement of the
reaction. As soon as the latter commences, the chemical action itself develops
such a heat, that it is useless, and might even be dangerous, to increase it by
any external action. The apparatus is fitted in addition to the charging and
discharging mechanism with the ordinary safety devices and a tap for discharging
the liquid.
All being arranged as has been described, the pulverized material is introduced
into the apparatus, and then the solvent is poured in. The agitator is then set in
motion, and all the particles of ore are forced consequently to come successively in
contact with it. After an agitation lasting from one hour to one hour and a half,
with some stoppages in order to allow the action to take place, the apparatus is
allowed to remain stationary.
The ore is soon covered with the liquid, which holds in solution almost all the
gold contained in such ore. This liquid, which is not yet saturated, may be run on
to a fresh quantity of ore to be treated, in the manner hereinbefore described.
The washing water is then introduced, and the agitators are caused to describe
several revolutions, experience showing pretty soon according to the more or
less argillaceous nature of the ore the quantity of water which should be
passed through the apparatus at one or more times, in order not to cause loss
of gold.
The other or so called "slow process
"does not require more complicated
apparatus. The following is a brief description of it.
A series of narrow but high cylinders, the diameter of which must always however
be in proportion to the height calculated on the basis that 15 centimetres of diameter
per metre of height is the best condition, are employed. These cylinders made of
enamelled metal, wood lined with lead, carburetted cast iron, or earthenware, are
provided at their base with a sort of network of suitable form intended to filter
the liquid. At the base they have a simple opening, or a short length of tube
ending in a single channel serving all the series of cylinders. The cylinders being
thus placed side by side, and arranged in series, the solvent is conveyed to the
upper part of each of them, taking care not to fill in too much ore. so that the
effervescence, which takes place, may not cause a portion of the solvent to be
ejected from the cylinder. When the effervescence commences, the upper part is
closed, and a little time is allowed for the liquid to pass through the whole mass
and collect at the bottom. It is then passed through a fresh series of cylinders
containing fresh ore, and so on successively until it is found to be sufficiently
saturated to proceed to precipitation. The operation is consequently a
methodical one.
If the richness of the ore under treatment be unknown, warning is given that
the solvent is saturated, or inactive, when it loses its suffocating, nauseous and very
characteristic odour. It is of course understood that the same washing water is
passed through the same series of cylinders in the same order.
This treatment may thus be carried out automatically, without effort, and
without great expenditure of manual labour, it being sufficient to have a pump,
and the necessary piping for feeding the series of cylinders. Pipes are arranged

page_text: for conveying regularly by means of pumps, the liquids to the points where their
action is to be exerted.
It is so easy to imagine an arrangement of this kind that it suffices to
mention it.
After the operation the cylinders are discharged into a carriage, or truck of
sufficient size to receive the ore from the whole series of cylinders, and then
replaced. A travelling hopper is employed for charging them.
Although the use of chloride of sulphur S,Cl, with which experiments have
been made for the treatment of gold ore as herein before described has been more
particularly specified it is understood that the right is reserved of using for this
same treatment, of analogous products resulting from the combination of sulphur
or chlorine with any one of the metalloids of the monatomic and diatomic
series, the expression metalloid defining the substances actually classed under this
heading.
1 11-
1 1000
A
COMPLETE SPECIFICATION (AMENDED).
Improvements in Gold Extracting Processes, and Apparatus
therefor.
ET
communication by LA SOCIÉTÉ POUR L'EXTRACTION INTÉGRALE
ECONOMIQUE DE L'OR, PROCÉDÉ DE RIGAUD, of 16 Rue Drouot, Paris,
in the Republic of France, Gold Extractors.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of The Agency for
Foreign Patent Solicitors, 6 Lord Street, Liverpool, and 6 Bank Street,
Manchester both in the County of Lancaster, 118 New Street, Birmingham
in the County of Warwick, and 322 late 31 High Holborn in the County of
Middlesex, Civil Engineer, do hereby declare the nature of this invention and in what
manner the same is to he performed, to be particularly described and ascertained in
and by the following statement :-
This invention has for its object an improved process for extracting gold from
its ore, allowing the extraction of the whole of the metal to be effected at a cost
much below that of the most improved processes at present employed.
This process consists in treating the gold ore with a powerful solvent which is
formed by the combination of sulphur and chlorine forming a chloride of
sulphur S₂Cl, which is, according to the remarkable works of Mr. Isambert, the
only clearly defined chloride of sulphur.
Although chlorine constitutes one of the elements of the solvent which is
employed, this improved process has no analogy with the processes based on the
use of free chlorine or nascent chlorine, and particularly with the very improved
method of Plattner, seeing that chlorine does not act in this form in our
process.
It may also be pointed out that as there exists only a single clearly defined
chloride of sulphur S,Cl₂, it is easy to deduce therefrom that all the chlorides of
sulphur only differ from one another by the greater or less saturation of their
solution with chlorine. This process for the economic treatment of gold ore is
based on this circumstance.
This process consists in introducing, into a suitable closed receptacle, ore mixed
with water in sufficient quantity to form a liquid mud.
Ore crushed, and sieved in a No. 30 sieve generally requires 10 to 15% of

page_text: water to bring it to this condition, but it is evident that more water will be
required according as the ore is more finely pulverized. When this has been done
it is slightly warmed, and the solution of chloride of sulphur super-saturated with
chlorine, is immediately introduced.
The reaction is a complex one, and becomes more complex according as there
are more metals present in the ore. In the simplest case, that is to say in an
alluvial ore, pan dirt, or native gold contained in a quartz gangue, there takes
place simply a contact of the combined solvents with the precious metal which is
dissolved almost instantaneously and entirely. The solution of gold mingles with
the water without being precipitated. A little sulphuretted hydrogen is formed as
a result of the small quantity of iron which the quartz contains, and a little
sulphate of lime which remains insoluble. It is only then necessary in this case
But it
to filter and wash, in order to collect the entire gold contained in the ore.
is not always alluvial- or quartz-mud which is to be treated, and then the reaction
is more complex without the treatment being more complicated.
A certain quantity of metals previously existing in the ore in the form of
sulphides are first separated from their compounds, and pass into the condition
of chlorides, some soluble, others (such as silver, quicksilver and the like)
insoluble. But there is formed at the same time sulphuric acid, and sulphuretted
hydrogen; the former precipitates the insoluble sulphates, the latter re-converts a
part of the others into sulphides, whilst owing to the heat which these chemical
actions cause, the sulphur released combines directly with the magnesium, copper,
iron, lead, cadmium and bismuth which have escaped the action of the
sulphuretted hydrogen, thus releasing and allowing to pass into the condition of
chloride, all the precious metal which these other various metals in their former
condition retained.
When the gold ore does not contain either antimony, zinc, or tin, as is very
frequently the case, the result of the reaction is found to be identical and similar
When on
in all points to the treatment of quartz, alluvial ores and the like.
the other hand these three metals are found in combination (a case almost
unknown) with gold ore, the use of this improved solvent must be dispensed with
for the moment.
Finally if only one of these metals be combined with the gold ore, it
passes with it into the chloride solution, and then it only requires to be treated
in
treatise on
by one of the suitable separating methods described any
chemistry.
A rapid and simple method of separation in the case where two of these metals
are combined with the gold ore will now be described.
When all the parts of the gold ore have been brought in direct contact with
the combination of sulphur and chlorine employed, the whole of the gold which
these ores contain, either in the form of native gold, or of sulphide, or of oxide,
is transformed into soluble chloride of gold, and it suffices to collect the whole
of this solution in order to extract the whole of the gold from its ore.
This is done by washing it in pure water, and in order to avoid having to
precipitate small quantities of gold in solution, in a sufficiently large quantity of
water, such washing water is then collected in a large vat or tank where it is
allowed to deposit its metallic gold under the action of air alone, and of the
organic elements which such water always contains in sufficient quantity to
produce sufficiently rapidly this result. The same washing water under these
conditions may serve a large number of times, which is a great advantage for
gold-mining operations where the scarcity of water creates real and
unsurmountable difficulties.
even
The part of the coloured but limpid solvent which, after filtration, contains the
gold except what the washing water has carried away, is treated with sulphate of
If care be
iron, which precipitates the precious metal in a metallic condition.
taken to only employ for the precipitation, the quantity of ferric salt actually
necessary according to the percentage of precious metal in the ore, this same

page_text: .
'solvent after having given up the gold contained in it, may serve again and again
for the further treatment of fresh ore, but in this case it is better not to carry
out the precipitation before the solvent is almost saturated with gold, that is to
say contains about half its weight in gold.
As already stated this solvent may be employed in two different ways, one
which may be called the slow process although it is still incomparably quicker
than the most recently known one, and the other which may be called the rapid
process, because the whole operation may be accomplished in a few hours
(crushing the ore, dissolving the gold, precipitation and combination of the
precipitate into an ingot of metal).
The
Any suitable apparatus consisting of a closed vessel made of enamelled cast
iron, or other suitable material capable of resisting the corrosive action of the
solvent, may be employed for carrying out this so called rapid process.
apparatus may be fixed or movable, and comprises an agitator, which enables
the material to be mashed so as to cause it to be thoroughly brought in contact with
the solvent. The apparatus must be capable of being heated by steam or by an
open fire. It must however be noted that this heating is not indispensable, and
especiably that it need not be prolonged. It only serves to hasten the
commencement of the reaction. As soon as the latter commences, the chemical
action itself develops such a beat, that it is useless, and might even be dangerous,
to increase it by any external action. The apparatus is fitted in addition to the
charging and discharging mechanism with the ordinary safety devices and a tap for
discharging the liquid.
All being arranged as has been described, the pulverized material is introduced
into the apparatus, and then the solvent is poured in. The agitator is then set in
motion, and all the particles of ore are forced consequently to come successively
in contact with it. After an agitation lasting from one hour to one hour and a
half, with some stoppages in order to allow the action to take place, the apparatus
is allowed to remain stationary.
or
The ore is soon covered with the liquid, which holds in solution almost all the
gold contained in such ore. This liquid, which is not yet saturated, may be run
on to a fresh quantity of ore to be treated in the manner herein before described.
The washing water is then introduced, and the agitators are caused to describe
several revolutions, experience showing pretty soon according to the more
less argillaceous nature of the ore the quantity of water which should be
passed through the apparatus at one or more times, in order not to cause loss of
gold.
The other or so called
"slow process
"does not require more complicated
apparatus. The following is a brief description of it.
A series of narrow but high cylinders, the diameter of which must always
however be in proportion to the height calculated on the basis that 15 centimetres
of diameter per metre of height is the best condition, is employed. These
cylinders made of enamelled metal, wood lined with lead, carburetted cast iron,
or earthenware, are provided at their base with a sort of network of suitable form
intended to filter the liquid. At the base they have a simple opening, or a short
length of tube ending in a single channel serving all the series of cylinders. The
cylinders being thus placed side by side, and arranged in series, the solvent is
conveyed to the upper part of each of them, taking care not to fill in too much
ore, so that the effervescence, which takes place, may not cause a portion of the
solvent to be ejected from the cylinder. When the effervescence commences, the
upper part is closed, and a little time is allowed for the liquid to pass through
the whole mass and collect at the bottom. It is then passed through a fresh series
of cylinders containing fresh ore, and so on successively until it is found to be
sufficiently saturated to proceed to precipitation. The operation is consequently a
methodical one.
If the richness of the ore under treatment be unknown, warning is given that
the solvent is saturated, or inactive, when it loses its suffocating, nauseous and very

page_text: characteristic odour. It is of course understood that the same washing water is.
passed through the same series of cylinders in the same order.
This treatinent may thus be carried out automatically, without effort, and without
great expenditure of manual labour, it being sufficient to have a pump, and the
necessary piping for feeding the series of cylinders. Pipes are arranged for
conveying regularly, by means of pumps, the liquids to the points where their
action is to be exerted.
It is so easy to imagine an arrangement of this kind that it is sufficient to-
mention it.
After the operation, the cylinders are discharged into a carriage, or truck of
sufficient size to receive the ore from the whole series of cylinders, and then
replaced. A travelling hopper is employed for charging them.
Although the use of chloride of sulphur S₂Cl, with which experiments have
been made for the treatment of gold ore as hereinbefore described has been more.
particularly specified, it is understood that the right is reserved of using for this
same treatment, analogous products resulting from the combination of sulphur or
chlorine with any one of the metalloids of the monatomic and diatomic series
the expression metalloid defining the substances actually classed under this.
heading.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, as communicated to me. by
my foreign correspondents, I am aware that it has been proposed to use sulphur
chlorides in combination with other reagents in gold extracting processes and I do
not claim such combination, but I declare that what I claim is :-
An improved process for extracting gold from its ores, consisting in treating
said ores
in a closed vessel with a powerful solvent such as chloride of
sulphur S,Cl, after first pulverizing them, and in then agitating and slightly
heating the mixture, thus producing as saturated a solution of chloride of gold as
possible, said solution being then treated with sulphate of iron which precipitates
the gold in a metallic condition, the other metals forming insoluble compounds
which are easily separated out; the whole substantially as hereinbefore.
described.