Improvements relating to the Extraction of Gold and other Metals from Ores, Tailings, Slimes and other Compounds containing the same, to Apparatus therefor, and to the Preparation of Solvents for Use in such Extraction.
Year: 1895

page_text: Date of Application, 2nd Dec., 1895
Complete Specification Left, 1st Sept., 1896-Accepted, 28th Nov., 1996
PROVISIONAL SPECIFICATION.
Improvements relating to the Extraction of Gold and other Metals
from Ores, Tailings, Slimes and other Compounds containing the
same, to Apparatus therefor, and to the Preparation of Solvents
for Use in such Extraction.
We, HENRY RYAN LEWIS, of 7 Drapers' Gardens, in the City of London,
Mining Engineer and Metallurgist, and CHARLES GELSTHARP, of 211 Jubilee
Terrace, Clayton, Manchester, in the County of Lancaster, Chemist and
Metallurgist, do hereby declare the nature of this invention to be as follows:-
Our invention relates to the extraction of gold and other metals from ores,
tailings, slimes and other compounds containing the same, and to apparatus
therefor, and also to the preparation of solvents to be used in such extraction.
One important feature of our said invention is the employment, in the extraction
of gold and other metals from the ores or other compounds, of hypochlorous acid
or bypobromous acid however obtained, or of a mixture of hypochlorous or hypo-
bromous and other oxi-acid of chlorine or bromine, or a mixture of hypochlorous
or hypobromous acid and any other suitable chloride or bromide or acid.
In the extraction of gold and other metals from ores or other compounds
according to our said invention, we first, if necessary, reduce the ores or compounds
to a fine state of division, and if necessary calcine the same, with or without the
addition of a suitable chloride.
We then treat the ores or compounds by methods or processes such as those herein-
after mentioned so as to render the gold soluble in water or in water containing
bisulphate of soda or a suitable chloride or acid, and we extract the gold and
other metals by washing and precipitation or electro-deposition as hereinafter
mentioned.
The ores or compounds in a fine state of division, are placed in suitable vats,
tanks or barrels, and when necessary leached with water, or with a dilute acid or
alkaline solution.
According to one method or process of bringing the gold to a soluble condition,
the ores or compounds are then digested with a solution of hypochlorous acid or
hypobromous acid, or other oxi-acid of chlorine or bromine, or a mixture of
hypochlorous or hypobromous or other oxi-acid of chlorine or bromine, with other
suitable chloride, bromide or acid, or such solution or mixture is caused to circulate
through the ore or compound, until all the gold is rendered soluble in water, or in
water containing bisulphate of soda or a suitable acid.
Or the ores or compounds are mixed with chloride of lime or with a solution of
bleaching powder, or bleaching liquor or other suitable hypochlorite or hypo-
bromite; and gaseous or
liquid carbonic acid, acetic acid or other suitable acid, is
added to or caused to circulate through the mixture until all the gold is rendered
soluble; or gaseous or liquid hypochlorous acid or hypobromous acid is or may be
added to or caused to circulate through the mixture until all the gold is soluble
in water, or in a mixture of water and a suitable chloride or acid.
Or the ores or compounds are mixed with finely divided carbonate of calcium or
other suitable carbonate, sulphate, phosphate, arseniate or oxide and water, and
then gaseous or liquid chlorine or bromine or gaseous or liquid hypochlorous acid

page_text: or hypobromous acid is added to or caused to circulate through the mixture unth
all the gold is rendered soluble.
Or the ores or compounds are mixed with a solution of bleaching powder, or
other suitable hypochlorite or hypobromite, and then chlorine or bromine is added
to or caused to circulate through the mixture until all the gold is rendered soluble
in water, or in water and a suitable chloride or acid.
If the ores or compounds are of such a nature as to render it necessary, they are
treated, by any of the above mentioned methods or processes in suitable vats, tanks
or barrels, under pressure and agitated.
The solutions obtained as above mentioned containing the gold and other metals,
are decanted or filtered off, and, if desired, mixed with or caused to circulate
through a further quantity of the ores or compounds. The ores or compounds
are then washed with water, or with a mixture of water and acid or a suitable
chloride, until free from gold, and the washings are mixed with or caused to
circulate through a further quantity of the ores or compounds. When the solution
contains sufficient gold, it is treated with carbon, sulphuretted hydrogen, sulphide
of sodium, or other sulphide, or with metallic copper, zinc, iron, or compounds of
these metals. The precipitated gold and other metals may then be treated for the
separation of the metals, by any well-known method or process.
Or the solution containing the gold and other metals is run into or caused to
circulate through suitable covered vats or tanks, containing a number of suitable
anodes and cathodes which are connected with a dynamo-electric machine or other
source of electricity. When a current of electricity is passed through the solution,
the gold and other metals are deposited on the cathodes, and the chlorine or
bypochlorous acid or mixture of the two is liberated at the anode. The liberated
gas is conveyed by suitable pipes or tubes, into a suitable chamber containing
slaked lime for the production of bleaching powder, or into milk of lime, soda or
magnesia, or other suitable compound, to produce bleaching liquid; or the chlorine
or mixture of chlorine and hypochlorous acid may be used to treat a further
quantity of the ores or compounds as above mentioned. The liberated chlorine
may also be passed into or mixed with water containing carbonate of lime, or other
suitable carbonate, oxide, sulphate, or chloride so as to produce hypochlorous acid
to be used again in the process above mentioned.
The solution from which the gold has been precipitated, may also be used to
treat a further quantity of the ores or compounds. If desired, the ores (after
treatment with cyanide of potassium in the ordinary way to extract gold and
silver) are treated with hypochlorous acid, as above mentioned, so as to profitably
extract the 2 dwts. to a few grains of gold left in the ores or compounds after
treatment with the cyanide.
If the ores or compounds contain silver, the whole of it is converted into argentic
chloride by the hypochlorous acid, and if the hypochlorous acid solution contains
an excess of salt, or other suitable chloride, the chloride of silver is dissolved out
along with the gold; by using hypochlorous acid containing very little chloride of
sodium or other chloride, however, the chloride of silver will be allowed to remain
in the ore or compound after the gold is all dissolved out. The chloride of silver
is or may be then dissolved out of the ore or compound by a strong solution of
salt or other chloride or by hyposulphite of soda solution, and can then be
precipitated or deposited by electrolysis or by other suitable methods or
processes.
The solvent for use in extracting the gold and other metals, we produce by
mixing the proper quantity of carbonic, sulphuric or other suitable acid with, or
adding the same to a solution of bleaching powder, bleaching liquor, or other
suitable hypochlorite or hypobromite, so as to combine with the base, and thus set
the hypochlorous acid or hypobromous acid free. When necessary the solution is
filtered or decanted, and is then ready for diluting to the required strength for use
Or the hypochlorous acid or hypobromous acid is or may be distilled off, and
condensed in a suitable condenser, or in the wet or moist ore.

page_text: Or we produce the hypochlorous acid or hypobromous acid by electrolysing a
solution of any suitable chloride or bromide, having a suitable carbonate, sulphate,
oxide or phosphate near the anode.
Or we submit the solution containing the gold as above mentioned to electro-
lysis, and mix the liberated chlorine with carbonate of lime, or other suitable
carbonate, sulphate, phosphate, chloride or oxide, so as to form hypochlorous acid.
Or we pass chlorine into carbonate of lime or other suitable carbonate, sulphate,
phosphate or oxide so as to produce hypochlorous acid.
Or we form the hypochlorous acid by passing into a solution of bleaching
powder, or other suitable hypochlorite at a proper temperature, the chlorine
obtained while electrolysing the solutions containing the gold and other metals;
or by first precipitating the gold from the solution, by means of copper or zinc
and then electrolysing the solution containing the copper and zinc; or by other
suitable methods or processes.
If desired we form the hypobromous acid in similar ways, using bromine in
place of the chlorine.
The apparatus which we use in the extraction of the gold and other metals,
according to our said invention, comprises one or more tanks, vats or other suitable
vessels for producing and storing the solvents. These vessels are preferably
placed at a higher level than the lixiviating tanks to which they are connected by
pipes for conveying the solvent thereto.
We provide one or more vats, tanks or barrels of suitable capacity, and when
intending to use the solvent in a gaseous state or to pass chlorine or carbonic or
other acid through the ore or compounds, we place a tightly fitting cover on one
tank or barrel, which we provide with one or more doors and tubes for charging
and discharging the ore, for introducing the liquid, and for conveying away any
unused gas or vapour into other tanks or vats containing ore or liquid for absorbing
the gas. If desired we place near the bottom of each tank or vat a perforated or
porous false-bottom, over which we place straw, heather, asbestos, flannel or other
suitable filtering material. The space below the false-bottom we connect by pipes
with the next tank or vat, and, where necessary, we provide an injector or pump
for assisting in causing the liquid to circulate up through the ore or compounds or
down through the ore or compounds in the first tank or vat and then up through
or down through the ore or compounds in the next tank or vat. We also connect
the space below the false-bottom by pipes to the carbonic acid, hypochlorous acid
or chlorine generators so that the gases may be conveyed under the false-bottom
of the vat and thus caused to circulate up through the ore; and when necessary
we fix in the centre of the vats or tanks a central shaft to the end of which
we attach one or more suitable arms; the said shaft is made to revolve for
the purpose of agitating the ore; or we connect the vats, tanks or barrels with
suitable gearing for the same purpose.
In carrying on another of our above mentioned methods of treatment, we
connect the leaching or lixiviating tanks or vats by means of suitable tubes and
valves with the hypochlorous, carbonic or other acid or chlorine generators (or
with the depositing vats), and also with settling tanks or receiving vats for
receiving the gold solution; and in or connected to these tubes we provide an
injector or force-pump, so arranged that, when the liquid in the lixiviating tank is
caused or allowed to flow into the settling or receiving vat, it causes a vacuum, so
that the hypochlorous, carbonic or other acid or chlorine rushes into the lixiviating
vats, and where the liquid is caused to flow or is forced back into the lixiviating
vats, the excess of hypochlorous, carbonic or other acid or chlorine is forced back
into the generators, so that no hypochlorous, carbonic or other acid or chlorine is
lost. Or the injector or force-pump may be used to force the hypochlorous,
carbonic or other acid or chlorine up through or down through the ore or
compounds in the lixiviating vats.
For precipitating the solution containing the gold and other metals obtained by
lixiviating the ore or compounds, we provide a suitable number of vats or tanks

page_text: and so arrange them that the liquid can be agitated when necessary and caused to
flow from one vat to another as required. When we wish to precipitate the gold
and other metals by means of sulphuretted hydrogen, we place a tightly fitting
cover over the tanks and provide suitable doors in the covers; we also connect the
tanks to tubes for conveying the gases from one vat to another, and for conveying
sulphuretted hydrogen from the sulphuretted hydrogen supply into the precipitating
vats. When we precipitate the gold and other metals from the solution by
electrolysis, we construct one or more suitable covered vats, or one long vat
containing a number of partitions so as to form a number of compartments, in
which we place a number of anodes and cathodes of suitable material, the anodes
and cathodes we connect to a dynamo-electric machine or other convenient source
of electricity, and we provide the depositing vats with suitable valves for the
removal of the gold, etc., and the covers with suitable tubes for conveying the
chlorine or other gas to where it is required or into the lixiviating tanks, and we
also provide these depositing vats with tubes and valves for causing the liquid to
properly circulate round the anodes and cathodes, and, where necessary, through
fresh ore or compounds. When we use copper, zinc or other solid or liquid
precipitant, the precipitating tanks need not be covered.
Dated the 2nd day of December 1895.
D. YOUNG & Co.,
11 & 12 Southampton Buildings, London, W.C.,
Agents for the Applicants.
COMPLETE SPECIFICATION.
Improvements relating to the Extraction of Gold and other Metals
from Ores, Tailings, Slimes and other Compounds containing the
same, to Apparatus therefor, and to the Preparation of Solvents
for Use in such Extraction.
We, HENRY RYAN LEWIS, of 7 Drapers' Gardens, in the City of London,
Mining Engineer and Metallurgist, and CHARLES GELSTHARP, of 211 Jubilee
Terrace, Clayton, Manchester, in the County of Lancaster, Chemist and
Metallurgist, do hereby declare the nature of this invention and in what manner
the same is to lie performed, to be particularly described and ascertained in and by
the following statement :-
Our invention relates to the extraction of gold and other metals from ores,
tailings, slimes and other compounds containing the same, and to apparatus
therefor, and also to the preparation of solvents to be used in such extraction.
The chief object of our said invention is to provide for the extraction of the
gold and other metals at a lower cost and in a simpler, safer and more economical
manner than is practicable with chlorine, and for the profitable extraction of gold
from very refractory ores and from ores containing very small quantities of gold,
and also from tailings and the like after the same have been treated by the
cyanide process, for which purposes chlorine cannot be profitably employed.
One important feature of our said invention is the employment, in the manner
substantially as hereinafter described, of hypochlorous acid or of hypobromous acid
or of a solution containing hypochlorous or bypobromous acid together with
chlorides or bromides.
We have found that a dilute solution of hypochlorous acid can be employed to
much greater advantage than chlorine in the extraction of gold from ores, tailings
and slimes, and more especially from those which contain very small quantities of
gold, since hypochlorous acid possesses an oxydizing power superior to that of
chlorine. It is moreover, much quicker in action than cyanides.

page_text: In the extraction of gold and other metals from ores or other compounds
according to our said invention, we first, if necessary, reduce the ores or
compounds to a fine state of division and if necessary wash the same and calcine
them with or without the addition of salt or other suitable chloride.
We then treat the ores or compounds by either of the methods or processes
hereinafter described so as to render the gold soluble in water or in water
containing bisulphate of soda or a suitable chloride or acid; and we extract the
gold and other metals by washing and precipitation or by electro-deposition as
hereinafter described.
As the hypochlorous acid is the acid which we find it most advantageous to
employ, we will more particularly describe herein our methods or processes as
carried on with that substance; but we wish it understood that we can also use
hypobromous acid or mixtures of hypochlorous or hypobromous acid and suitable
chlorides or bromides.
In carrying our said invention into practice, the ores or compounds, in a fine
state of division, are placed in vats, tanks, barrels or other suitable vessels, and,
when necessary, leached with water, or with a dilute acid or alkaline solution, and
are then treated with or subjected to the action of hypochlorous acid for example,
by one or other of the following methods or processes, viz. :-
1. The ores or compounds are digested or leached with the solution of hypo-
chlorous acid, or the solution of hypochlorous acid is caused to circulate through
the said ores or compounds, until all the gold is rendered soluble in water, or in
water containing bisulphate of soda or a suitable acid or chloride.
2. The ores or compounds are first mixed with chloride of lime (bleaching
powder) or with bleaching liquor or with a solution of bleaching powder or of a
suitable chloride or hypochlorite, and then gaseous or liquid carbonic acid, acetic
acid or other suitable acid is added to or caused to circulate through the mixture
until, by means of the hypochlorous acid liberated in contact with the ores or
compounds, all the gold is rendered soluble in water or in a mixture of water and
acid or bisulphate of soda.
3. Gaseous or liquid hypochlorous acid is mixed with or caused to circulate
through the ores or compounds until all the gold is soluble in water, or in water
and acid.
4. The ores or compounds are mixed with finely divided carbonate of calcium
or other suitable carbonate, oxide, sulphate, or phosphate, and water, and then
gaseous or liquid chlorine or bromine is added to or caused to circulate through
the mixture until all the gold is rendered soluble. The carbonate, oxide, sulphate
or phosphate used in this process should be such as is capable of producing hypo-
chlorous or hypobromous acid when chlorine or bromine is caused to circulate
through the mixture.
5. The ores or compounds are mixed with a solution of bleaching powder, or
other suitable hypochlorite and then chlorine, or chlorine and a suitable acid is
added to or caused to circulate through the mixture until all the gold is rendered
soluble in water or in water and acid.
If the ores or compounds are of such a nature that the hypochlorous acid cannot
penetrate into the centre of the particles, the said ores or compounds are treated
by any of the above described methods or processes in suitable vats, tanks or
barrels, under pressure, by forcing into such vats, tanks or barrels compressed air
or steam, the ores or compounds being preferably agitated during such treatment.
The solutions obtained as above described, containing the gold and other metals,
are then decanted or filtered off, and if desired mixed with or caused to circulate
through a further quantity of the ores or compounds in other tanks or vessels.
The ores or compounds contained in the first tank or vessel are then washed or
leached with water, or with a mixture of water and acid or a suitable chloride,
until they are free from gold and other metals; the solutions or washings thus
obtained are, if desired, mixed with or caused to circulate through a further
quantity of the ores or compounds in other tanks or vessels.

page_text: We obtain the gold from such solutions by one or other of the following methods
or processes, viz. :-
1. When the solution obtained by lixiviating the ores or compounds contains
sufficient gold, we allow it to run off into a receiving or settling tank, so that any
fine ore it may contain may settle down, and thus be prevented from contaminating
the precipitate containing the gold. The clear solution in the settling tank we
then run into the precipitating tanks, where we precipitate the gold and other
metals either by adding to or passing into it in regular quantities sulphuretted
hydrogen, sulphurous acid, sulphide of sodium, sulphate of iron, carbon, copper,
zinc or iron, or compounds containing the same. The precipitated gold and other
metals are then allowed to settle, and the clear solution is run off, and used for
leaching fresh ore. The precipitated gold and other metals we then run into a
filter, or wash with water. We then dry, and when necessary roast and melt the
precipitate so as to obtain the gold and other metals, or we sell the dry precipitate,
or treat it with sulphuric acid, or by other well-known processes, so as to
obtain the gold free from other metals. We then precipitate the silver by means
of copper and the copper by means of zinc or iron, and the zine by means of
carbonate or sulphide of sodium, or we precipitate these metals by electrolysis as
hereinafter described.
2. Or when the solution obtained as herein before described contains sufficient
gold, we decant or filter it off, and cause it to flow into a receiving tank, where
any fine ore contained in it, is allowed to settle. The clear solution we then cause
to flow into, or circulate through one or more covered vats, containing a number of
cathodes of lead or other suitable metal, and a similar number of carbon anodes,
which we connect with a dynamo-electric machine or other source of electricity.
By these means we cause a current of electricity to pass through the solution, thus
causing the gold and other metals to deposit on the cathodes, and the chlorine or
hypochlorous acid to be liberated at the anodes. When the cathodes have been
sufficiently coated with the gold and other metals, we remove them from the vats,
and either melt them and thus obtain the gold and other metals, or we scrape and
brush the cathodes, and thus obtain the gold and other metals which we then treat
with sulphuric or other acid, to dissolve the metals, and leave behind the pure
gold, which we then melt and run into bars. To the solution containing the metals
we add metallic copper to precipitate the silver, which we wash, dry and melt and
run into bars. We then precipitate the copper by means of zinc or iron, which
we then wash, dry, and melt and run into ingots. The zinc we precipitate by
means of carbonate of soda or sulphide of sodium.
The chlorine or hypochlorous acid liberated at the anodes, we convey by suitable
tubes either into the leaching vats, for treating fresh ore as previously described,
or into the carbonic acid generator containing carbonate of lime, or other carbonate,
oxide, sulphate or phosphate, for the production of carbonic acid and bypochlorous
acid for use in treating fresh ores.
3. Or when the solution contains sufficient gold, after allowing it to settle as
previously described, we run it into the precipitating tanks, and add to it, or cause
it to circulate through finely divided copper or zinc, until all the gold and silver is
precipitated. The precipitated gold and silver thus obtained we wash, dry and
sell, or treat it with sulphuric acid, which dissolves the silver, leaving the gold in
a pure state, which we then melt and run into bars. The silver we precipitate
with zinc or copper, or with chloride of sodium. The precipitated silver we then
melt and run into bare. After precipitating the gold and silver with copper or
zinc, we pass the solution containing these metals into the covered vats containing
the anodes and cathodes previously described. When only a small quantity of
copper is present, we add a little metallic zinc, which precipitates the copper,
which we then wash, dry, and melt and run into ingots. We then pass the electric
current through the solution, which causes the zinc to deposit on the cathodes and
the chlorine to be liberated at the anodes. The chlorine we convey by suitable
tubes either into the leaching vats for treating fresh ore as previously described, or

page_text: into the carbonic acid generator, containing carbonate of lime, or other carbonate,
oxide, sulphate or phosphate, for the production of carbonic acid, and hypochlorous
acid, or other hypochlorite, bleaching powder or liquid.
When the ores or compounds contain any base metal soluble in water, or when
the ores have been washed with salt or other chloride, if necessary we leach or
wash the ore or compound with water, or with water and acid or a chloride, or with
water and an alkali or alkaline earth for the removal or partial removal of the
base metals, before treating them with hypochlorous acid.
The ore after it has been treated as above described, or ores that do not
require previous washing, when desired, we saturate with carbonic, sulphuric or
other suitable acid (not oxalic acid) and then cause a solution of bleaching powder,
or other hypochlorite to circulate through the ore, until, by means of the
hypochlorous acid liberated in contact with the ores or compounds, all the gold
is rendered soluble. We then wash out the gold, and precipitate it as above
described.
After extracting the gold from ores or compounds by any of our methods or
processes above described, if any silver should remain in the ore, it is in the form
of chloride. This chloride we then extract by causing a strong hot solution of
salt or other chloride, or of hyposulphite of soda, or an ammoniacal solution to
circulate through and digest the ore, until all the silver is soluble, which we then
wash out with water, and from the solution thus obtained, we precipitate the
silver by means of or by adding to the solution metallic copper or zinc, or by
electrolysing the solution. We then obtain the silver in the metallic state, which
we then wash, dry and melt and run into bars for sale.
The hypochlorous acid for use in extracting the gold or other metals from the
ores or compounds, we prepare by one of the following methods or processes, viz. :—
1. We dissolve bleaching powder, or a suitable hypochlorite in water, and, when
necessary, filter or decant off the clear solution; we then mix with or cause to.
circulate through it the proper equivalent quantity of carbonic acid, sulphuric,
acetic, or other suitable acid, to combine with the base and thus set the hypochlorous
acid free. When we use carbonic acid or sulphuric acid, a precipitate is formed,
which we allow to settle. We then decant or filter off the clear solution, which
we dilute either with water, or with the solution obtained in the treatment of a
previous lot of ore, to the proper strength to suit the quality of the ore to be-
treated. It is then ready for use. Or we
run the solution containing the
hypochlorous acid into a retort or covered tank which is connected with a condenser
or with the lixiviating vats by means of tubes. We then heat the retort or tank
to the proper temperature, until the hypochlorous acid is distilled off and condensed
either in the condenser or in the wet ore in the leaching vats.
2. We mix a quantity of finely divided carbonate of lime or other suitable
carbonate, oxide, sulphate, phosphate, acetate or oxi-chloride with water, or with
the waste solution obtained from treating a previous lot of ore, in one or more
covered vessels, and then pass chlorine (either liquid or gaseous) into or up through
the mixture, until a sufficient quantity of hypochlorous acid is formed. We then
filter or decant off the clear solution and dilute it down with water, or with the
waste solution obtained from the treatment of a previous lot of ore, to the proper
strength to suit the grade of ore to be treated. It is then ready for use.
Or we
run the solution containing the hypochlorous acid into a retort or covered tank, and
distil off the hypochlorous acid as above described.
3. We pass chlorine produced by the electrolysis of the solutions containing the
gold and other metals, or chlorine however obtained, through a solution of bleaching
powder, or of a suitable hypochlorite, kept at a proper low temperature, until the
solution is saturated, and then, if necessary, pass a current of air or carbonic acid
through the solution, to drive out the excess of chlorine. We then allow any
precipitate that is formed to subside, filter or decant off the clear solution and
dilute it down to the proper strength with water or with a saturated solution of a
suitable chloride, or with the waste solutions obtained in treating a previous lot of

page_text: ore. Or we run the clear solution into a retort or covered tank, and distit ana
condense the hypochlorous acid as bereinbefore described.
4. We pass a quantity of dilute solution of any suitable chloride through the
electrolytic vats and so proportion the size of the electrodes to the strength of the
electric current that hypochlorous acid, or a mixture of hypochlorous acid and a
hypochlorite of the base is formed when the electric current is caused to pass
through the solution. To the solution thus produced, we add, when necessary,
carbonic, sulphuric, acetic or other suitable acid, and we filter or decant off the
clear solution, which we then dilute to the proper strength to suit the quality of
ore to be treated. It is then ready for use.
If desired we prepare hypobromous acid by any of the methods above described,
using bromine in place of chlorine.
The apparatus we use for extracting the gold and other metals from the ores or
compounds, by means of hypochlorous acid, by the methods herein described,
consists of a number of vats, tanks, or vessels connected together with the necessary
tubes, valves, pumps or injectors, and, in some instances, with a dynamo-electric
machine, and so arranged on different levels that the liquid or solution containing
the solvent, will flow from the tanks in which it is prepared into the tanks containing
the ore or compound, and, after circulating through the ore or compound, it will
flow into the settling tanks, and then into the precipitating or depositing vats, and
can then be pumped or forced back to the top level for use in treating fresh ore.
The said apparatus also comprises two or more vats or tanks for the production
of carbonic acid, by the action of chlorine, or of sulphuric or other acid, or
carbonate of lime, or other carbonate, and so arranged on different levels that the
generated carbonic acid can be forced either into the tanks containing the ore or
compounds, or into tanks containing a solution of bleaching powder or other
hypochlorite, as may be desired.
In the accompanying drawing
Figures 1 and 2 show, in sectional elevation and in plan respectively, one
arrangement of our apparatus.
Figures 3 and 4 show, in sectional elevation and in plan respectively, a modified
arrangement of the said apparatus.
Figures 5 and 6 are similar views showing another arrangement or modification
of our apparatus.
The apparatus arranged as shown in Figures 1 and 2, is well adapted for the
production of hypochlorous acid according to the first method or process herein-
before described, and for the extraction of gold or other metals from ores or other
compounds by the first and third methods or processes herein before described.
Carbonic acid, for example, is generated in the vat or tank a from a suitable
carbonate; hypochlorite of lime or other suitable hypochlorite is dissolved in
water in the vat or tank 6 so as to form a solution thereof, and the clear solution
flows through the pipe m into the vat or tank c, in which it is treated with carbonic
acid supplied from the tank a through the pipe l. The ores or compounds to be
lixiviated or leached are placed in the vats or tanks d, e, and into these tanks is
allowed to flow through the pipes n, n' the hypochlorous acid from the vat or
tank c; the hypochlorous acid is caused to circulate through the ores in the vats d
and e until all the gold is rendered soluble as above described. The solution
containing the gold and other metals is allowed to run through a pipe t into a
settling tank f, from which the clear solution is allowed to run through the pipe
into the precipitating vats 9, 9'. The precipitated gold and other metals being
allowed to settle in these vats, the clear solution is then run off through the pipe
and is returned, by an injector i (worked by steam or compressed air as may be
most convenient) or by a suitable pump, to the tank or vat b to be used for the
treatment of a further quantity of ore. The precipitated metals are conveyed
through the pipes r, r¹ to the filter tank or press h.
w, w are pipes provided with valves for starting and stopping the flow of liqui
from one tauk to another.

page_text: The ores in the tanks d, e, are, after the above treatment, washed or leached as
herein before described until they are free from gold, the solutions or washings thus
obtained are run through pipes p, p₁ into the tank f and thence into the vats g, g¹,
whence they are returned to be circulated through a fresh quantity of ore.
The higher level vats can be placed on wood trestles standing on a cement or
asphalte floor, so that any leakage of gold solution may be caught in a small tank
sunk in the floor. The leaching vats we provide with a door in the bottom so that
a wagon can be run under them, and the washed ore dropped into the wagon and
thus quickly discharged.
If desired we place near the bottom of each tank or vat a perforated or porous
false-bottom, over which we place straw, heather, asbestos, flannel or other suitable
filtering material. The space below the false-bottom we connect by pipes with the
next tank or vat, and where necessary we provide an injector or pump for assisting
in causing the liquid to circulate up through the ore or compound or down through
the ore or compounds in the first tank or vat d and then up through the ore or
compounds in the next tank or vat e. We also connect the space below the false-
bottom by pipes to the carbonic acid, hypochlorous acid or chlorine generators so
that the gases may be conveyed under the false-bottom of the vat and thus caused
to circulate up through the ore; and when necessary we fix in the centre of the
vats or tanks a central shaft to the end of which we attach one or more suitable
arms; the said shaft is made to revolve for the purpose of agitating the ore; or
we connect the vats, tanks or barrels with suitable gearing for the same purpose.
In the modified arrangement shown in Figures 3 and 4, which is well adapted
for the extraction of the metals by the second method or process hereinbefore
described, the carbonic acid generated in the tank a is collected in a gas-holder c, c².
The solution of hypochlorite of lime or other hypochlorite from the vat 6 is
allowed to run through pipes n, n¹ into the leaching tanks d and e, and carbonic
acid from the holder c, c¹ is then delivered through the pipes o, o' into the liquid in
the said tanks d, e. In or connected to these tubes or pipes we provide an injector
or force pump, so arranged that, when the liquid in the lixiviating tank is caused
or allowed to flow into the settling or receiving vat, it causes a vacuum so that the
hypochlorous, carbonic or other acid or chlorine rushes into the lixiviating vats,
and where the liquid is caused to flow or is forced back into the lixiviating vats,
the excess of hypochlorous, carbonic or other acid or chlorine is forced back into
the generators, so that no hypochlorous, carbonic or other acid or chlorine is lost.
Or the injector or force pump may be used to force the bypochlorous, carbonic or
other acid or chlorine up through or down through the ore or compounds in the.
lixiviating vats. The other parts of the apparatus are arranged substantially as
described with reference to Figures 1 and 2, with the exception that the leaching
vats d, e have air-tight covers.
In Figures 5 and 6 we have shown an arrangement well adapted for the
preparation of hypochlorous acid according to the second method or process
above described and for the extraction of metals according to the fourth or fifth
methods or processes above described. Finely divided carbonate of lime and water
are placed in the vat or tank a for the production of hypochlorous acid, and the
generation of carbonic acid, when chlorine is passed into it. Hypochlorite of lime
or other hypochlorite is placed in the tank b, and the vat c is lor containing the
solvent or hypochlorous acid solution. The tanks a and b are connected, by
pipes m, m respectively, with the vat or tank c, and the tank a is also connected
with the tank 6 by a pipe 7 for conveying carbonic acid into the latter. The vats
or tanks
9, g¹ are, in this arrangement, used as electro-depositing vats, and they
are connected by a pipe k with the lixiviating vats d, e and also with the tank a,
so that the chlorine liberated at the anodes may be used for treating further
quantities of ore, or may be conducted into the tank a for the purpose of
generating carbonic acid, and hypochlorous acid. s is a dynamo-electric machine.
X, X are the anodes and Y, Y are the cathodes, which are suitably connected with
the dynamo s.

page_text: The leaching vats d, e we provide with tightly fitting covers, with suitable doors
in the covers for charging the ores or compounds into the vats.
We also provide a tramway over the leaching vats for conveying the ores to the
vats.
In extracting gold with this apparatus according to the fourth process herein-
before described, the ores are mixed with carbonate of calcium or other suitable
carbonate, oxide, sulphate or phosphate and water, in the tanks d, e, and chlorine
from the depositing vats g, g', or from any other suitable source is conveyed by
the pipe k into the said vats d, e for the purpose of producing in contact with the
ore hypochlorous acid, which immediately attacks the gold, the latter can then be
obtained as hereinbefore described.
Or we make hypochlorous acid by conveying chlorine from the depositing
vats g, g or from any other suitable source through the tube k into the vat a for
the production of hypochlorous acid and carbonic acid, and we convey this carbonic
acid by the pipe into the vat 6 which contains hypochlorite of lime for the
production of hypochlorous acid. The hypochlorous acid can then be used as
above described for the treatment of ores in the vats d, e.
In extracting gold according to the fifth process above described, with the
apparatus shown in Figures and 6, the ores are mixed with a solution of
bleaching powder or other suitable hypochlorite in the vats d, e and then
chlorine is conveyed through the pipe k into the said vats and allowed to circulate
through the mixture therein until all the gold is rendered soluble as above
described.
The above method of procedure are given merely as examples as the production
of the hypochlorous acid, and the extraction of the precious metals according to
our said invention can be carried out in various ways with the apparatus shown or
with other suitable arrangements of apparatus.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we wish it to be clearly
understood that we do not claim broadly or irrespectively of our improvements
berein described the use of chlorine, as we are aware that various processes have
already been devised and described for the extraction of gold by means of free
chlorine; but we declare that what we claim is :-
1. In the extraction of gold or other metals from ores or other compounds
containing the same, the use of hypochlorous or hypobromnous acid or of a solution
containing free hypochlorous or hypobromous acid, substantially in the manner
hereinbefore described and for the purpose specified.
2. The precipitation of the gold and other metals in such a manner that we
recover the chlorine or bromine and reproduce hypochlorous or hypobromous acid
adapted for use again in the extraction of the metals from the ores or compounds,
substantially as hereinbefore described.
3. The extraction of gold or other metals from ores or compounds containing
the same, by a process in which the said ores or compounds are first mixed
with bleaching powder or bleaching liquor or with a solution of a suitable
chloride or hypochlorite, and then gaseous or liquid carbonic acid, acetic acid or
other suitable acid is added to or caused to circulate through the mixture,
substantially as hereinbefore described and for the purpose specified.
4. The extraction of gold or other metals from ores or other compounds
containing the same, by a process in which the said ores or compounds are
mixed with finely divided carbonate of lime or other suitable carbonate, oxide,
sulphate or phosphate and water, and then gaseous or liquid chlorine or bromine is
added to or caused to circulate through the mixture, substantially as herein before
described and for the purpose specified.
5. The extraction of gold or other metals from ores or compounds containing
the same, by a process in which the said ores or compounds are mixed with a
solution of bleaching powder or of a suitable bypochlorite, and then chlorine

page_text: or without a suitable acid is added to or caused to circulate through the-
ure, substantially as herein before described and for the purpose specified.
The extraction of gold or other metals from ores or other compounds
ining the same, by a process in which the said ores or compounds are-
ed first with a solution of bleaching powder or of a suitable hypochlorite-
ith a solution of a suitable hypobromite and then with carbonic, acetic,
uric or other suitable acid, or vice versa, so as to liberate hypochlorous or
bromous acid in contact with the said ores or compounds, for the purpose.
e specified.
The preparation of the hypochlorous or hypobromous acid by either of the
wing methods or processes, viz. :-
(a.) By passing through, or adding to a solution of bleaching powder or of a
suitable hypochlorite or hypobromite, carbonic acid or acetic, sulphuric or
other suitable acid in such proportion that it will combine with the base and
liberate bypochlorous or hypobromous acid, filtering, decanting or distilling
off the hypochlorous or hypobromous acid, and condensing it, substantially
as herein before described.
(b.) By passing chlorine (or bromine) obtained either by the electrolysis of
the solutions containing the gold and other metals or by the electrolysis of the
chloride (or bromide) of copper or zinc after the gold has been precipitated
by means of copper or zinc, or in any other convenient manner, through
water containing finely divided carbonate of lime or other suitable carbonate,.
oxide, sulphate or phosphate.
(c.) By passing chlorine (or bromine) obtained by the electrolysis of the
solution containing the gold and other metals as herein described or
otherwise, into a solution of bleaching powder or of a suitable hypochlorite
(or bypobromite) kept at the proper low temperature, and when necessary
passing air or carbonic acid or other acid through the mixture, and when.
necessary filtering, decanting or distilling off the hypochlorous (or hypo-
bromous) acid so produced and condensing it, substantially as herein before
described.
(d.) By electrolysing a dilute solution of a soluble chloride as herein.
described, so as to produce the hypochlorous acid, and then filtering,
decanting, or distilling this solution and condensing the hypochlorous.
acid as described.
Mixing the hypochlorous acid with a solution of a chloride, or with the waste.
ions obtained from the treatment of previous lots of ore, as hereinbefore
ibed and for the purpose specified.
The simultaneous production of carbonic acid and hypochlorous acid, by
ng chlorine obtained by electrolysing the solutions containing the gold and
metals, or otherwise, through water containing finely divided carbonate of
or other suitable carbonate, and passing the liberated carbonic acid into or
gh a solution of bleaching powder or of a suitable hypochlorite (either in
ct with the ore or in a separate vessel) and thus liberating hypochlorous
and producing carbonate of lime or other carbonate for use again.
The improved apparatus constructed and arranged as shown in the
panying drawing for the purposes specified.
Dated this 1st day of September 1896
D. YOUNG & Co.,
11 & 12 Southampton Buildings, London, W.C.,
Agents for the Applicants.