An Improved Process for the Extraction of Gold from its Ores, and Apparatus Employed therefor.
Year: 1894

page_text: Date of Application, 27th Nov., 1894
Complete Specification Left, 25th Apr, 1895-Accepted, 15th June, 1895
An Improved Process for the Extraction of Gold from its Ores, and
Apparatus Employed therefor.
I, LOUIS CLÉMENT DAUMAS, Doctor of Medicine, of 35 Rue Boissy d'Anglas,
9 Cite du Retiro, Paris, France, do hereby declare the nature of this invention to
be as follows:-
This invention relates to an improved process for the extraction of gold from its
ores and consists essentially in mixing protochloride of sulphur saturated with
chlorine directly with the auriferous ore, then subjecting the mixture to heat,
afterwards filtering the solution resulting from such mixture, and precipitating the
gold while the solution is still warm; the solution of protochloride of sulphur and
the chlorine disengaged during the process being recovered for use over and over
again.
The apparatus employed for carrying out my process may consist of the following
parts viz.--a large tank for containing a solution of protochloride of sulphur
alone; a smaller tank for containing a solution of protochloride of sulphur
saturated with chlorine; a chamber wherein the ore is treated and the gold
dissolved; a vat wherein the gold is precipitated, a recipient containing an
earthenware filtering slab; a receiver for containing the deposited gold and its
precipitant; a compressed air chamber; and piping, controlled by suitably arranged
cocks, for connecting these parts together. All the parts that come into contact
with the chemicals employed are made of glass or stoneware and encased in sheet
iron with a suitable cement between.
The gold dissolving chamber is composed of glass or other suitable substance
that is not affected by hot chlorine and its shape may be such that its lower portion
for about a third of its length is of smaller diameter than the upper portion while
the intervening part between the upper and lower portions may be made tapered. It
is covered with an outer metal casing and is surrounded with a steam jacket This
chamber has an upper and a lower cover, the upper one being provided with
suitable openings, one of which is for the jacket of a thermometer, another for a
compressed air tube having bent branches of unequal length at its inner end which
cause the ore to be stirred up by the action of the air; another for the introduction
of the ore; another for an air outlet pipe; and another for a pipe fitted with a
safety valve and having two connections one communicating with the before
mentioned compressed air-tube and the other with the small tank. The lower or
reduced part of the gold dissolving chamber is furnished with a glass cylinder
having a sloping lip or rin at its upper part beneath which is a perforated stoneware
disc made in halves which are so pivotted that they are capable of assuming an
inclined position for the purpose of allowing the ore supported thereon to fall to
the bottom of the gold dissolving chamber. This disc is provided with a recess for
receiving a filter composed of some very porous substance. The lower cover of
the said gold dissolving chamber is formed with a concave portion having notches
for the reception of two perforated plates with an asbestos tissue between said
concave portion constituting a chamber which is connected by a pipe to the
precipitating vat. The lower cover is likewise provided with a large outlet or
opening having a special fastening device that is conical at its lower part,
cylindrical at the middle and terminating in two branches at its upper portion

page_text: which latter when brought into contact with the lower part of the two halves of the
disc cause them to assume a horizontal position and thus close the opening at the
top of the glass cylinder.
The precipitating vat is cylindrical and made of glass protected externally with
a casing of cement and iron. Its upper cover is formed with apertures one of
which is for a gauge-glass; another for a pipe conveying the liquid from the gold
dissolving chamber to the vat; another for a manhole fastened with a screw and
yoke; another for a compressed air tube similar in construction to that employed
in the gold dissolving chamber; and another for an air outlet pipe. Suitable
connections are also provided for enabling this vat to be connected to the air
compression chamber. The lower cover of this vat communicates with the said
gauge glass and leads to the recipient containing the stoneware filtering slab through
a suitable inlet chamber. This recipient is divided into two compartments by the
before mentioned stoneware filtering slab one of which is in communication with
the receiver for containing the deposited gold and the other with the large tank.
The receiver for containing the deposited gold is made of glass and is of cylindrical
form having a horizontal top and an oblique bottom, and contains a horizontal slab
of stoneware said receiver being surrounded with a casing of cement and iron and
with a steam jacket. An opening is provided at the bottom which is closed by a
special fastening that is conical at its lower end, cylindrical at its middle and
terminates at its upper part in an enlargement which when brought against the
slab of stoneware forces it firmly against the lower edge of a cylindrical
prolongation that projects from the top cover into the receiver, and a side opening
is formed in the said receiver to permit of the stoneware slab being removed This
receiver is in communication with the large tank beforementioned. All joints in
the apparatus are preferably made of lead coated with platinum foil and U pipes
may be provided on the various air outlet pipes for preventing the entrance of
moisture to the apparatus.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.
COMPLETE SPECIFICATION.
An Improved Process for the Extraction of Gold from its Ores, and
Apparatus Employed therefor.
I, LOUIS CLEMENT DAUMAS, Doctor of Medicine, of 35, Rue Boissy d'Anglas,
Cite du Retiro 9 Paris, in the Republic of France, do here by 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 an improved process for the extraction of gold from its
ores and consists essentially in mixing directly with the auriferous ore protochloride
of sulphur impregnated with chlorine, then subjecting the mixture to pressure and
heat, afterwards filtering the solution, next dissociating or precipitating the gold
while the solution is in a hot condition and finally subjecting the solution to a
second filtration; the protochloride of sulphur, and the chlorine disengaged during
the process, being both recovered for use over and over again.
The apparatus I employ for carrying out my process consists of the following
principal parts viz. :-a tank for containing a solution of protochloride of sulphur
alone; a smaller tank for containing a solution of protochloride of sulphur
impregnated with chlorine, a chamber wherein the ore is treated with the
protochloride of sulphur and chlorine and the gold thereby dissolved; a vat or
chamber wherein the gold is precipitated; a recipient or filtering chamber wherein
the second filtration takes place; a chamber for receiving, the deposited gold; a

page_text: compressed air-chamber; piping connecting these various chambers together; and
suitably arranged cocks for controlling the working of the apparatus.
In order that my invention may be clearly understood and readily carried into
effect I will proceed to describe the same more fully with reference to the
accompanying drawings in which :
Figure 1 is a diagrammatic view shewing the general arrangement of the
apparatus.
Figure 2 is a vertical section of the gold dissolving chamber.
Figure 3 is a vertical section of the gold precipitating chamber.
Figure 4 is a vertical section of the filtering chamber and of the gold depositing
chamber.
Figure 5 is a vertical cross section of the filtering chamber.
In Figure 4a portion of the central part of the filtering chamber has been
broken away.
Like letters of reference indicate similar parts in all the figures.
A, B are the two tanks, the former containing the solution of protochloride of
sulphur alone, and the latter the solution of protochloride of sulphur impregnated
with chlorine. C is the gold dissolving chamber; D the gold precipitating
chamber; E the filtering chamber; F the gold depositing chamber; G the
compressed air or gas chamber; and H a pump for feeding said chamber G with
the compressed air or gas
All the parts that come into contact with the chemicals employed are made of
some material that will withstand the action of said chemicals, such as glass,
stoneware, wrought or cast iron coated with magnetic oxide or enamel or any other
substance that is not attacked by the chemicals employed
The gold dissolving chamber C as shewn in the drawings (Figure 2) is of
funnel-shape, that is to say its lower portion is of smaller diameter than the upper
portion and the intervening part is tapered. I may however employ any other
suitably formed chamber for my purpose.
This chamber is surrounded with a
steam-jacket and is provided with an upper cover e and a lower cover f. e¹ is a
thermometer having a dial for indicating the temperature within the chamber.
e2 is a tube for conducting compressed air or gas from the chamber G to the branch
pipes ex situated within the chamber C. These branch pipes are of unequal
length and are disposed radially with their outer ends curved inwardly all in the
same direction for the purpose hereinafter stated. es is an opening for enabling the
ore to be introduced into the chamber. eis an air outlet pipe having a cock e.
e is a pipe through which the contents of tank B enter the chamber C. This
pipe is provided with a safety valve B7 and two lateral connections e ethe
former of which communicates with the compressed air tube e and the latter with
the tank B, each of said connections being respectively provided with a cock ex
and ex.
Fitting into the lower part of the chamber C is a cylinder g having at its upper
part a sloping lip or ring and a central transverse piece g². Immediately below
the underside of said lip or rim g' is a perforated disc h made in halves which are
pivotted at h³ ³ to the transverse piece g³ so as to permit of said halves assuming
the position indicated in dotted lines. The upper side of the perforated disc is
recessed at h³ for the reception of some filtering medium such as pieces of glass
and slag wool. The lower cover f is formed with a concave portion ƒ having
notches or channels for the reception of two perforated plates ff with asbestos or
slag wool interposed between them, through which the liquid, after percolating
through the glass and slag wool above the disc h, passes prior to flowing away by
the pipe f* to the precipitating chamber D. The said perforated plates f² fare
preferably so arranged that they will not become accidentally displaced when
compressed air or gas is allowed to enter the dissolving chamber through the pipe f
for the purpose of clearing the filters. The lower cover is provided with a central
opening which is normally kept closed by a plug i. This plug is formed with an
inwardly projecting arm terminating in horns which are so arranged that, when

page_text: the plug i is in its closed position, they come against the lower part of the pivotted
halves of the disc hand cause them to assume their horizontal position, thereby
closing the opening in the mouth of the cylinder g. In the drawings I have shown
a lead ring g interposed between the cylinder g and the interior of the chamber C,
for making a tight joint between these parts, but instead of this ring I may employ
an annular lead fillet located above said cylinder g and having its internal
circumference inclined so as to offer little if any impediment to the downward
movement of the ore within the chamber C. A lead joint ring g is likewise
provided between the rim of the pivotted disc and the lip g¹ and I also provide
lead fillet gs between the pivotal portions of the disc and the transverse piece g².
The precipitating chainber D (Figure 3) consists of a cylindrical vessel
surrounded with a steam jacket D¹ and having end covers d d. d¹ is a gauge-glass
whose lower end is connected to the horizontal pipe d× communicating with the
lower part of said chamber D. The liquid from the dissolving chamber C is
conducted to the chamber 1 through the pipe ƒª which is controlled by a cock fo
This pipe is also provided with means for enabling the pipe G' from the compressed
air chainber G to be coupled thereto. d² is a manhole through which access can
be had to the interior of the chamber D. The cover for this manhole is kept
closed by a screw working in a yoke d. d is a tube for conducting compressed air
to the branch pipes dx which latter are similar in construction to the pipes ex
already mentioned. is a pipe leading to the upper part of the tank B, said pipe
being provided with two lateral connections de d the former of which communicates
with the pipe d5 at a point above the safety valve B' and the latter with the air
tube d controlled by a cock ds. This cock also serves to control the entrance of
compressed air through the inlet d. do is an air outlet tube controlled by a
cock d, said air outlet tube being similar to the one with which the gold
dissolving chamber is provided. The horizontal pipe dx situated at the lower end
of the chamber D communicates with the filtering chamber E and is controlled by
the cock xx. The chamber D is also preferably provided with a thermometer
having a dial similar to that shewn in Figure 2.
The filtering chamber E (Figures 4 and 5) consists of a vertically arranged
rectangular vessel which is divided vertically into two compartments by the porous
slab or partition Ex and these compartments I term respectively anterior and
posterior compartments. This chamber is provided with end covers E¹ E² the
upper one of which is furnished with a junction box E* communicating at its top
with the chamber D through the pipe dx and at its bottom with the posterior com-
partment of the filtering chamber by means of the conduits E. E and E are
cocks with which the upper cover E' is also provided the former of which com-
municates with the posterior compartment and the latter with the anterior
compartment. These cocks are provided with ineans for enabling the pipe of the
compressed air chamber G to be connected thereto and serve to regulate and
control the entrance of the compressed air to the filtering chamber. The lower
cover E2 is furnished with two junction boxes E E" similar in construction to the
junction box E. The one E' communicates with the anterior compartment by the
conduits Es and the other E communicates with the posterior compartment by
the conduits E10. A¹ is a pipe connecting the junction-box E with the tank A
the said pipe being provided with a cock A² which is located in proximity to said
tank and is free to be put into communication with the air-pump H. The junction-
box E is in connection with the gold depositing chamber F, communication
between them being controlled by the cock F¹.
The gold depositing chamber F (Figure 4) consists of a cylindrical steam
jacketted vessel having a horizontal top and an oblique bottom. It is provided
with a lateral opening F2 which is normally kept closed by the cover F³ and
fastening F. The upper cover F has a cylindrical prolongation F which
extends into the chamber F, and the lower cover F has a detachable plug F
whose inner end is prolonged so as to come against a horizontally arranged porous
slab F when said plug is in its closed position and thus keep said slab firmly

page_text: pressed against a joint ring Fx interposed between the lower edge of the cylindrical
prolongation F and the said slab so as to produce a fluid tight joint between these
parts. The lower part of this depositing chamber communicates with the tank A
by means of the pipe A'.
The tanks A and B (Figure 1) are of cylindrical form, the one A being at least
twice the capacity of the other B. The tank A is provided with an air outlet
pipe controlled by a cock A' and with a gauge-glass A whose lower end opens
into a pipe A communicating with the bottom of the tank A, and the top of tank B.
A cock A' is provided for controlling the passage of the contents of the tank A
into the tank B. The tank B is stean jacketted and is provided at its upper part
with a thermometer having a dial (not shewn in the drawings). B₁ is a gauge-glass
which communicates with the pipe B, and B2 is an air-outlet pipe controlled by a
cock B³. The said pipe B is in communication with the lower part of the said
tank and likewise comminunicates with the pipe B and with the pipe e. ex is a cock
for directing and controlling the flow of the liquid from the tank B to the gold
dissolving chamber C, and for allowing the chlorine to escape from chamber C to
chamber B.
The operation of the apparatus is as follows:-The tank B having been charged
with protochloride of sulphur impregnated with the required quantity of chlorine,
and the tank A with protochloride of sulphur alone, the lower aperture of
chamber C is closed as also is the cock f³. The roasted auriferous ore in a
powdered condition is introduced into the chamber C through the opening e³ which
is then closed and the cock e³ for allowing the escape of air from said chamber is
opened. The cock x is next opened to allow the liquid protochloride of sulphur
impregnated with chlorine to run into the chamber C. This cock is kept open
until all the liquid contained in tank B has entered the chamber C, after which
said cock is again closed. The tank B is then filled again with protochloride of
sulphur from the tank A by opening the cock A' which is closed again after this
filling operation is completed. Hot compressed air or gas from the chamber G is
now allowed to enter the tube e² by opening the cock ex and said air or gas by
escaping through the branch pipes ex into the chamber C produces an agitation of
the inass within the said chamber. After a few minutes the entrance of the com-
pressed air or gas is stopped by closing the cock ex and the mass within the
chamber C is allowed to settle into a uniform layer thereof. The air outlet e is
then closed. The temperature within the chamber C is then raised to about 130° C.
by allowing steam to circulate in the jacket C¹. At this temperature all the
gold contained in the ore is dissolved the gold being in the state of a double
chloride of gold and sulphur. The cock ex is now opened to put the pipe
cominunication with the pipe B' and the excess of chlorine is liberated in the
chamber C and is allowed to escape by the pipes B' B' and B' into the tank B
where it is absorbed by the protochloride of sulphur which has already been
admitted into said tank.
in
When the operation has so far progressed the cock √ is opened and the pressure
of the compressed air or gas (which is equal to about three atmospheres) forces all
the liquid contained in chamber C into the precipitating chamber D: the cock d
being left open during this time to allow of the escape of air through the air
outlet d¹º. The gauge glass d' having indicated that all the liquid has entered the
chamber D the cocks and d" are closed and stean is allowed to circulate in the
jacket D¹ thereby raising the temperature within the chamber D to the boiling
point of the liquid. All chlorine remaining in the liquid is thus driven off and
returns to the tank B by the pipes d' de; the cocks d¹ d¹³ being opened for this
purpose.
The gold in solution in the protochloride of sulphur within the chamber D in
the form of a double chloride of gold and sulphur can be precipitated by intro-
lucing into said chamber a suitable precipitant such as finely powdered charcoal.
Hot compressed air or gas is then allowed to pass into the chamber D through the
ube d whereby a violent agitation is produced in the liquid and the powdered

page_text: charcoal is caused to come into intimate contact with the solution and the precipita-
tion of the gold takes place. Instead of employing the powdered charcoal for
precipitating the gold I may employ a suitable vapour such as the vapour of
sulphur. Or the double chloride of gold can be dissociated so that the gold will
remain in a free state.
After this precipitation or dissociation has taken place the cock dxx is opened
and the liquid in the tank D is forced through the pipe dx into the posterior
compartiment of the filtering chamber E by the action of the compressed air.
Froin the posterior compartiment the liquid is forced through the filtering slab Ex
into the anterior compartment and rises in the pipe A', while the gold with its
precipitant (if the latter be employed) is left in the posterior compartment. The
cock dxx, is then closed, and the cock F¹ is opened to establish communication
between the posterior compartment of chamber E and the depositing chamber F.
The cock A is then also opened to admit hot compressed air or gas which by
entering the pipe A' forces the liquid contained therein and in the anterior com-
partment of the chamber E, back into the posterior compartment and thence into
the chamber F. As the liquid passes through the posterior compartment it carries
with it the gold previously retained in said compartiment, and as said liquid is
forced through the filtering slab F in the chamber F, the gold with its precipitant
(if any of the latter has been employed) is left upon said slab while the liquid
passes along the pipe A3 back to the tank A. In order to hasten this latter part
of the process compressed air can also be forced into the chamber E through the
inlets controlled by the cocks E° E. Any vapour of protochloride of sulphur
that may remain in the chamber F is driven off by steam circulated in the jacket
of this chamber. Finally the lateral aperture F² of chamber F is opened and
the slab removed by detaching the plug F. Upon this slab the gold and its
precipitant (if any of the latter has been used) will be found.
In order to remove the ore, from the chamber C after it has been treated by my
process, it is only necessary to lower the plug thereby releasing the halves of the
disc which then assume the position shewn by dotted lines in Figure 2 by their
own weight. The ore is thus allowed to drop out of said chamber C through the
opening in the lower cover.
The pipes B1 B5 and d are preferably so arranged that they meet at a common
Junction where they are controlled by the cock di
All the joints between the covers and bodies of the various vessels or chambers
are preferably made of lead coated with platinum foil, or of pure platinum, although
any other suitable substance may be used for the purpose provided it will make
a good air tight joint and not be detrimentally affected by the chemicals employed
in the process.
As shown in the drawings the various air outlet pipes may be provided with
U tubes which may contain chloride of calcium for preventing the entrance of
moisture to the apparatus
Instead of arranging the various members of the apparatus in a superimposed
manner as represented in Figure 1 of the drawings I may if found more convenient
arrange then approximately on the same level, thereby enabling the various
members and cocks to be more readily reached.
Having now particularly described and asertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. The process of treating auriferous ore for the extraction of gold therefrom,
consisting in mixing with the ore a solution of protochloride of sulphur impreg-
nated with chlorine, subjecting the mixture to pressure and heat to form a double
chloride of gold and sulphur, filtering the solution; precipitating the gold or
dissociating the salt of gold from such solution while the latter is still hot, and
finally subjecting the solution to a second filtration, substantially as described and
for the purposes specified.

page_text: 2. The method of separating the gold from the liquid in which it is suspended,
by means of two filters one of which presents a large filtering surface and the
other a small filtering surface for the purpose specified.
3 The apparatus for use in treating auriferous ore for the extraction of gold
therefrom, consisting essentially of a tank for containing a solution of protochloride
of sulphur alone; another tank for containing a solution of protochloride of
sulphur impregnated with chlorine, a chamber wherein the ore is treated with the
protochloride of sulphur and chlorine solution and wherein the solution is separated
from the ore by filtration; a gold precipitating chamber, a vertical filtering
chamber; a gold depositing chamber; pipes connecting these various chambers
and suitably arranged cocks for controlling and working the apparatus substantially
as described.
4. In apparatus for treating auriferous ore the construction of the gold dissolving
chamber substantially as described with reference to Figure 2 of the accompanying
drawing.
5. The means for enabling compressed air or gas to be admitted to the gold
dissolving chamber for producing a uniform layer of the inass within said chamber
substantially as described
6. The construction and arrangement of the horizontally arranged filter within
the gold dissolving chamber, said filter being divided into halves capable of turning
about pivots, substantially as described and for the purposes specified.
7. The means for operating the divided filter substantially as described and
shewn with reference to Figure 2 of the accompanying drawings.
8. Constructing the lower cover of the gold dissolving chamber with an annular
filter substantially as described with reference to Figure 2 of the accompanying
drawings.
9. In apparatus for treating auriferous ore, the gold precipitating chamber
constructed substantially as described with reference to Figure 3 of the
accompanying drawings.
10. The means for enabling compressed air or gas to be admitted to the gold
precipitating chamber for causing the precipitant to come into intimate contact
with the solution substantially as described.
11. In apparatus for treating auriferous ore a filtering chamber provided with
a vertical filtering slab or partition dividing said chamber into two compartiments
substantially as described with reference to Figures 4 and 5 and for the purpose
specified.
12. In apparatus for treating auriferous ore the gold depositing chamber
constructed substantially as described with reference to Figure 4 and for the
purpose specified.
13 The general construction arrangement and combination of parts constituting
my apparatus for extracting gold from auriferous ores substantially as described
with reference to the accompanying drawings.
Dated this 25th day of April 1895.
L. C. DAUMAS.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.