An Improved Regenerative Process for the Treatment of Sulphide Ores.
Year: 1896

page_text: • Date of Application, 16th July, 1896
Complete Specification Left, 7th Oct., 1896-Accepted, 12th June, 1897
PROVISIONAL SPECIFICATION.
Chemist.
An Improved Regenerative Process for the Treatment of
Sulphide Ores.
I, OLIVER IMRAY, of No. 28 Southampton Buildings, Chancery Lane, in the
County of London, Chartered Patent Agent, do hereby declare the nature of this
invention to be as follows:-
My invention relates to the treatment of sulphide ores, and more particularly
zinciferous sulphide ores, containing galena and argentiferous galena, gold and
other metals, and has for its object the extraction of the several metallic ingredients
and also the utilization of certain products of the process for the regeneration of
the materials employed and for obtaining certain by-products of commercial
value.
According to my invention, raw sulphide ore is treated by hydrochloric
acid (HCI) causing disintegration of the ore and formation of certain metallic
chlorides of which use is made for obtaining the precious metals; also sulphuretted
hydrogen (H,S) is produced of which use is made for the obtaining of fresh
supplies of (HCI) hydrochloric acid. From the sulphuretted hydrogen, not only
are fresh supplies of hydrochloric acid obtained during the process hy the
application of salt, but also certain by-products in the form of caustic soda, and
other soda products. Portions of these products are used for the treatment of the
aqueous chlorides obtained in the first part of the process, the excess being dealt
with commercially.
I shall describe my invention referring to the accompanying drawing shewing
apparatus for carrying it into effect. The sulphide ore taken from the mine floors,
without pulverising it, is placed in suitable vats or digesters A lined with suitable
material capable of resisting the action of corrosive acids. A number of these
digesters A with their accompanying appliances are arranged in series. They are
provided with gas-tight lids and their bottoms are arrauged with three tiers of
gratings A. The openings in the gratings are graduated, the uppermost being the
largest, and the lowest heing the smallest, so that only fine particles of ore can
pass through the lowest into a crucible B below. The crucibles B are provided
with heating apparatus C preferably gas jets supplied from a gasometer N by a
pipe C.
When the digesters A are charged with raw sulphide ore the gas-tight covers
are replaced, aqueous hydrochloric acid is introduced from a tank D and sprayed
into the upper portions of the digesters, whilst at the same time bydrochloric acid
gas is discharged from a generator E below the gratings A. By the combined
action of the aqueous and gaseous hydrochloric acid the ore is gradually
disintegrated and passes with the aqueous acid through the gratings.A into the
crucible B. The crucible B is constantly heated in order to maintain the aqueous
hydrochloric acid, now containing metallic chlorides, at the boiling point. The
digesters A and crucibles B being arranged in series, the aqueous acid is discharged

page_text: from the crucible B, No. 1 and raised by any suitable means into the tank D
of No. 2, and thence is sprayed over the ore in the No. 2 digester. It is passed in
this way from one digester to another until the hydrochloric acid has become
neutralised and a neutral saturated solution of metallic chlorides is obtained. This
saturated solution is then returned to the crucible B, No: 1 of the series. In the
meantime the whole of the ore e ntents of the digester A have become disintegrated
and have passed into the crucible B. The digester A No. 1 is then disconnected
and No. 2 in the series now becomes the first, and the digester A No. 1 when
charged again becomes the last of the series and so on in rotation.
Having described the circulation of the aqueous hydrochloric acid and its return
as neutralised solution of metallic chlorides, before describing its further treatment
for recovery of the metals, I will explain the circulation of the gaseous hydro-
chloric acid.
The gaseous bydrochloric acid rising through the contents of the digester A
No. 1 liberates sulphuretted hydrogen by its action upon the sulphides of the ore.
The gas so formed is carried by suitable pipe connections and discharged under
the gratings A, No. 2. After passing-through the ore in the digester No. 2 the
gases pass to the next in the series and so on until the hydrochloric acid gas
becomes neutralized and the sulphuretted hydrogen is practically free fron it.
To eliminate any final traces of (HCI) hydrochloric acid, the gases are conducted
through a purifying chamber filled with crushed antimony blende, and the pure
sulphuretted hydrogen is led into a gasometer N. From the gasometer N, it is
drawn for use as fuel wherever required.
The products of its combustion as fuel, which are sulphur dioxide (SO,),
aqueous vapour, and nitrogen, are collected by means of suitable flues, passed
through drying towers F for extraction of the aqueous vapor and discharged into
cylinders R arranged in proximity to the digesters A. The cylinders R are filled
with briquettes of common salt and are maintained at a temperature of about 500 C.
By the action of the sulphur di-oxide, air and steam upon the salt in the cylinders R,
hydrochloric acid gas is evolved and sodium sulphate or salt cake is produced as a
residue or by-product. This is from time to time removed and heated with carbon
to produce sodium sulphides for use in the recovery of zine as will hereafter be
described. The hydrochloric acid gas is conducted from the cylinders R into a
suitable tower L through which a continual stream of brine is passed from a
reservoir K above. By the action of the gaseous hydrochloric acid upon the brine,
sodium chloride is precipitated and aqueous hydrochloric acid is produced. The
aqueous acid is collected in a receptacle L at the base of the tower and is
conducted to the storage tank D. The nitrogen which passes with the gaseous
acid from the cylinders k, is drawn off by a chimney or otherwise eliminated.
The contents of the crucible B No. I now consist of disintegrated particles of
gangue and undecomposed ore which may be blende, galena or argentiferous, and
with these remain the silver chloride and the concentrated solution of aqueous zine
and lead chlorides which has been returned thereto after the circulation as detailed.
The temperature of the mass is gradually raised until it reaches about 300 C. The
lead and zine chlorides gradually fuse and by their action the silver chloride becomes
dissolved in the fused mass. As the fused inass of chlorides has a specific gravity
of about 4, any particles of ores still undecomposed sink to the bottom of the
crucible and can afterwards be removed for further treatment. The gangue mean-
while becomes suspended in the fused mass of chlorides and the whole is removed
whilst still hut to suitable closed drying towers F. The towers F are preferably
placed within a water tank F, so that the heat evolved by the hydroscopic action
of the zine chloride may be absorbed by the water, which is used as required in
other parts of the process. Into the upper portion of these drying towers F, the
sulphide dioxide aqueous vapour and other products of combustion are discharged
from the collecting flues as before described.
The aqueous vapour is absorbed by and dissolves the soluble metallic chlorides,
whilst at the same time any chloride of gold in the fused mass is reduced to the

page_text: metallic state by the sulphurous anhydride. The mass (as the chlorides are
dissolved by the aqueous vapor) passes through gratings at the bottom of the drying
towers F into a lower chamber where it is boiled with water acidulated with
hydrochloric acid. The hot aqueous solution of chlorides together with the gangue
is then drawn off into a lixiviating tank which forms the first of a series of precipi-
tating tanks.
As the gangue settles, the aqueous chlorides are drawn off into a second or
cooling tank. The residue of gangue left in the first tank is then washed with boiling
water until it is free from lend chlorides. The first tank now contains gaugue,
metallic gold and silver chloride, which may be recovered by any well known
means. The liquor drawn off from the first tank together with the washings is
now placed into a second or cooling tank provided if desired with zinc stirrers and
the lead chloride settles out. When the liquor in the second tank has cooled down,
the clear liquid is removed to the third tank of the series.
In this any remaining traces of lead chloride are decomposed by means of sodium
sulphate.
Lead sulphate is thus precipitated and the sodium sulphate contained in the
solution becomes sodium chloride. The liquor from this third tank is conveyed to
the fourth of the series which is fitted with a revolving stirring gear having long "
rods of metallic zine whereby the whole of the copper is precipitated.
The liquor is then removed to the fifth tank of the series, where it is oxidised by
any suitable means until the ferrous iron is converted into ferric iron when it is
treated with a solution of caustic soda and boiled. By this means the whole of the
remaining metallic chlorides are decomposed into hydroxides and the sodium chloride
is regenerated. The alkaline brine which still contains zinc and manganese is
aërated, the manganese being thrown down as manganese dioxide which can be used
in the production of chlorine. The liquor is then removed to a sixth tank wherein
the whole of the zine in the form of zinc sulphide is precipitated by means of sodic
sulphide or recovered by any known means.
This sodium sulphide has been obtained by heating with carbon the salt cake or
sodium sulphate resulting from the regeneration of the hydrochloric acid in the
cylinders R as before described.
The zinc sulphide may, if desired, be converted into zinc oxide for use in the
zinc electrolysing tank in order to maintain the strength of the solution and to keep
it neutral. The liquor in the final tank now contains sodium chloride. It is raised
by any suitable means into a brine tank K placed at the top of the tower L for the
production of common salt and aqueous hydrochloric acid, as already described.
It will be seen that in the process described there are three distinct circulations,-
1.) The circulation of the aqueous hydrochloric acid through the series of
digesters containing raw sulphide ore and its return to the first of the series of
crucibles in the form of saturated solution of lead and zinc chlorides, for the
extraction of the precious metals from the ore.
2.) The circulation of the gaseous hydrochloric acid through the several digesters
containing crude ore until it also has become neutralized and the sulphuretted
hydrogen resulting from its action on the sulphides in the ore after being used as
fuel is returned as sulphur dioxide which, by the use of salt, produces hydrochloric
acid which returns to the supply tanks, both in a gaseous and aqueous form.
3.) The circulation of the sodium chloride comprising first its use in generators
for the production of gaseous hydrochloric acid then in the lixiviating tanks in the
form of sodium sulphate and caustic soda for precipitation purposes, its subsequent
regeneration as sodium chloride and final recovery in the aqueous hydrochloric acid
towers for fresh use in the gaseous hydrochloric acid generators.
Date: 12h 1L 1000
ABEL & IMRAY,
Agents for the Applicant.

page_text: 277 OF PITTALION.
An Improved. Regenerative. Process for the Treatment of
Sulphide Ores.
I, OLIVER IMRAY, of No. 28 Southampton Buildings, Chancery Lane, in the
County of London, Chartered Patent Agent, do hereby declare the nature of
this invention and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement:--
My invention relates to the treatment of sulphide ores and more particularly
zinciferous sulphide ores, containing galena and argentiferous galena, gold and
other metals, and has for its. object the extraction of the several metallic
ingredients and also the utilization of certain products of the process for the
regeneration of the materials employed: and for obtaining certain by-products of
commercial value.
According to my invention,, raw sulphide, ore is treated by hydrochloric
acid (HCI) causing disintegration of the ore. and formation of certain metallic
chlorides of which use is made for obtaining the precious metals; also sulphuretted
hydrogen (HS) is. produced. of. which use is made for the obtaining of fresh
supplies of (HCI)- hydrochloric acid. From the action of the products of
combustion of the sulphuretted hydrogen upon salt not only are fresh supplies
of hydrochloric acid obtained but also salt cake as a by product.
Portions of these products are used for the treatment of the aqueous chlorides
obtained in the first part of the process, the excess being dealt with.commercially.
I shall describe my invention referring to the drawing accompanying my
Provisional Specification, shewing apparatus for carrying it into effect. The
sulphide ore taken from the mine Hoors, without pulverising it, is placed in
suitable vats or digesters A lined with suitable material capable of resisting the
action of corrosive acids. A number of these digesters A with their accompanying
appliances are arranged in series. They. are provided with gas-tight lids and their
bottoms are arranged with three tiers of gratings A!. The openings in the gratings
are graduated, the uppermost, being the largest, and the lowest being the smallest,
so that only fine particles of ore eau pass through the lowest into a crucible B
below.
The crucibles B are provided with heating apparatus C' preferably gas jets
supplied from a gasometer N by a pipe C.
When the digesters A are charged with raw sulphide ore the gas-tight covers
are replaced, aqueous hydrochloric acid is introduced from a tank D and sprayed
into the upper portions of the digesters, whilst at the same time hydrochloric acid
gas is discharged from a generator E below the gratings A. By the combined
action of the aqueous and gaseous hydrochloric acid the ore is gradually
disintegrated. and passes with the aqueous acid through the gratings A into. the
crucible B. The crucible B is constantly. heated in order to maintain the
aqueous bydrochloric acid, now containing metallic chlorides, at the boiling point.
The digesters A and. erucibles B being arranged in series, the aqueous acid. is
discharged from the crucible B, No. 1 and raised by any suitable means into the
tank D of No. 2, and thence is sprayed over the ore in the No. 2 digester. It is
passed in this way from one digester to another until the hydrochloric acid has
become neutralised and a neutral saturated solution of metallic chlorides is obtained.
This saturated solution is then returned to the crucible B No. 1 of the series. In
the meantime the whole of the ore contents of the digester A have become
disintegrated and have passed into the crucible B. The digester A No. 1 is

page_text: then disconnected and No. 2 in the series now becomes the first, and the
digester A No. 1 when charged again becomes the last of the series and so on.in.
rotation.
Having described the circulation of the aqueous hydrochloric acid and its return
as neutralised solution of metallic chlorides, before describing its further treatment,
for recovery of the metals, I will explain the circulation of the gaseous hydrochloric:
acid.
The gaseous hydrochloric acid rising through the contents of the digester A. No. 1
liberates sulphuretted hydrogen by its action upon the sulphides of the ore. The
gas so formed is carried by suitable pipe connections and discharged under the
gratings A No. 2. After passing through the ore in the digester No. 2 the gases
pass to the next in the series and so on until the, hydrochloric acid gas becomes.
neutralized and the sulphuretted hydrogen is practically free from it..
To eliminate any final traces of (HCI) hydrochloric acid, the gases are conducted.
through a purifying chamber filled with crushed antimony blende, and the pure:
sulphuretted hydrogen is led into a gasometer N. From, the gasometer N it is
drawn for use as fuel wherever required.
The products of its combustion as fuel, which are sulphur dioxide (SO2) aqueous
vapour. and nitrogen, are collected by means of suitable flues and pass through.
drying towers F containing fused chlorides for the extraction of the aqueous.
vapour and discharged into cylinders R arranged in proximity to the digesters A.,
The cylinders R are filled with briquettes of common salt and are maintained at a
temperature of about 500° C. By the action of the sulphur dioxide, air and steam
upon the salt in the cylinders R, hydrochloric acid gas is evolved and sodium
sulphate or salt cake is produced as a residue or by-product. This is from time to
time removed and heated with carbon to produce sodium sulphides for use in the
recovery of zinc as will hereafter be described. The hydrochloric acid gas is
conducted from the cylinders R into a suitable tower L through which a continual
stream of brine is passed from a reservoir K above. By the action of the gaseous
hydrochloric acid upon the brine, sodium chloride is precipitated and aqueous
hydrochloric acid is produced. The aqueous acid is collected in a receptacle L³.
at the base of the tower and is conducted to the storage tank D. The nitrogen
which passes with the gaseous acid from the cylinders R, is drawn off by a chimney
or otherwise eliminated.
The contents of the crucible B No. 1 now consist of disintegrated particles of
gangue and undecomposed ore which may be blende, galena or argentiferous, and
with these remain the silver chloride and the concentrated solution of aqueous zinc,
and lead chlorides which has been returned thereto after the circulation as detailed..
The temperature of the mass is gradually raised until it reaches about 300° C..
The lead and zinc chlorides gradually fuse and by the action of the fused zinc.
chloride the silver chloride becomes dissolved in the fused mass. As the fused.
mass of chlorides has a specific gravity of about 4, any particles of ore still
undecomposed sink to the bottom of the crucible and can afterwards be removed
for further treatment. The gangue meanwhile becomes suspended in the fused.
mass of chlorides and the whole is removed whilst still hot to suitable closed
drying towers F.
The towers F are preferably placed within a water tank F', so that the heat.
evolved by the hygroscopic action of the zinc chloride may be absorbed by the
water which is used as required in other parts of the process. Into the upper
portion of these drying towers F, the sulphur dioxide aqueous vapour and other
products of combustion are discharged from the collecting Hues as before:
described.
The aqueous vapour is absorbed by and dissolves the soluble metallic chlorides,
whilst at the same time any chloride of gold in the fused mass is reduced to the
metallic state by the sulphurous anhydride.
The mass (as the chlorides are dissolved by the aqueous vapour) passes through.
gratings at the bottom of the drying towers F into a lower chamber where it is.

page_text: boiled with water acidulated with hydrochloric acid. The hot aqueous solution of
chlorides together with the gangue is then drawn by pipe F2 off into a lixiviating
tank which forms the first of a series of precipitating tanks. As the gaugue
settles, the aqueous chlorides are drawn off into a second or cooling tank. The
residue of gangue left in the first tark is then washed with boiling water until it is
free from lead chlorides. The first tank now contains gangue, metallic gold ant
silver chloride, which may be recovered by any well known means.
The liquor
drawn off from the first tank together with the washings is now placed into a
second or cooling tank provided if desired with zinc stirrers and the lead chloride
settles out. When the liquor in the second tank has coolel down, the clear liquid
is removed to the third tank of the series. In this any remaining traces of lead
chloride are decomposed by means of sodium sulphate.
Lead sul hate is thus precipitated and the sodium sulphate contained in the
solution becomes sodium chloride. The liquor from this third tank is conveyed to
the fourth of the series which is fitted with a revolving stirring gear having long
rods of metallic zine whereby the whole of the copper is precipitated. The liquor
is then removed to the fifth tank of the series, where it is oxidised by any suitable
ir cans until the ferrous iron is converted into ferric iron when it is treated with a
solution of caustic soda and boiled. By this means the whole of the remaining
metallic chlorides are decomposed into hydroxides and the sodium chloride is
regenerated. The alkaline brine which still contains zinc and manganese is aerated,
the manganese being thrown down as manganese dioxide, which can be used in the
production of chlorine. The liquor is then removed to a sixth tank wherein the
whole of the zinc in the form of zinc sulphide is precipitated by means of sodic
sulphide or recovered by any known means.
This sodium sulphide has been obtained by heating with carbon the salt cake or
scdium sulphate resulting from the regeneration of the hydrochloric acid in the
cylinders R as before described.
The zinc sulphide may, if desired, be converted into zinc oxide for use in the
zine electrolysing tank in order to maintain the strength of the solution and to keep
it neutral. The liquor in the final tank now contains sodium chloride.
It is raised by any suitable means into a brine tank K placed at the top of the
tower L for the production of common salt and aqueous hydrochloric acid, as
already described.
It will be seen that in the process described there are three distinct circulations,
1.) The circulation of the aqueous hydrochloric acid through the series of
digesters containing raw sulphide ore and its return to the first of the series of
crucibles in the form of saturated solution of lead and zinc chlorides, for the
extraction of the precious metals from the ore.
2.) The circulation of the gaseous hydrochloric acid through the several digesters
containing crude ore until it also has become neutralized and the sulphuretted
hydrogen resulting from its action on the sulphides in the ore after being used as
fuel is returned as sulphur dioxide which, by the use of salt, produces hydrochloric
acid which returns to the supply tanks, both in a gaseous and aqueous form.
3.) The circulation of the sodium chloride comprising first its use in generators
for the production of gaseous hydrochloric acid then in the lixiviating tanks in the
form of sodium sulphate for precipitation purposes, its subsequent regeneration as
sodium chloride and final recovery in the aqueous hydrochloric acid towers for
fresh use in the gaseous hydrochloric acid generators.
In the above description the process is detailed as relating to zinciferous sulphide
ores. In the treatment of galena and argentiferous galena it has to be somewhat
modified as follows. Zinc chloride is first fused in the crucible and the raw ore in
a finely divided state either alone but preferably mixed with lead sulphate and lead
oxide poured therein. The lead in the ore is reduced and sinks to the bottom of
the crucible as metallic lead, whereas the gangue with adhering silver chloride rises
and becomes admixed with the fused chloride of zinc. The fused mass is then

page_text: removed for the recovery of the silver and zinc in the manner herein before
described and the lead is poured off into suitable cakes.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I am aware that the
various parts of the process described are singly or in certain combinations well
known, I therefore would have it understood that I do not claim as my invention
any one of them singly or specifically or any two or more of them together in any
combination except in the particular combinations described, but I declare that
what I claim is :-
1. In the treatment of argentiferous sulphide ores the herein described process
consisting of their disintegration by the combined action of aqueous and gaseous
hydrochloric acid (HCI) at the same time causing the aqueous hydrochloric
acid (HCl) to circulate through fresh supplies of raw ore until it becomes a
saturated solution of lead and zinc chlorides, subsequently returning this solution
to the wholly or partially disintegrated ore and the fusing by heat the whole of the
chlorides resulting from the disintegration.
2. In the treatment of argentiferous sulphide ores in which the ore has been
wholly or partially disintegrated by the combined action of aqueous and gascous
hydrochloric acid (HCI) the separation of the nudecomposed ore for further
treatment by fusing the whole of the chlorides produced in the disintegration,
such fusion resulting in the admixture of the gangue with the fused mass and the
settling of the undecomposed ore to the bottom of the crucible.
3. In the treatment of argentiferous sulphide ores in which the chlorides
formed by the disintegration of the ore by the action of hydrochloric acid (HCI)
have been fused as set forth in Claim 1, the subsequent process for the recovery of
the metallic contents of the fused mass, cousisting in the application of aqueous
vapour and sulphur dioxide (SO2), whereby the metallic contents are obtained as
an aqueous chloride solution, subsequently boiling the same in water acidulated
with hydrochloric acid (HCI) and finally precipitating the metals therefrom by any
known process as in suitable precipitating tanks.
4. In the treatment of argentiferous sulphide ores, the herein described process
consisting in obtaining sulphuretted hydrogen (H,S) by the action of gaseous
hydrochloric acid (HCI) upon the sulphides of the ore under treatment, sub-
sequently utilising the aqueous vapour accompanying the sulphur dioxide (SO)
resulting from the combustion of the sulphuretted hydrogen (H,S) for the purposes
of dissolving in a suitable drying chamber the fused chlorides obtained in the
manner as set forth in Claim 1.
5.In the treatment of argentiferous sulphide ores the herein described process
consisting of the production of sulphuretted hydrogen (H,S) by the action of the
gaseous hydrochloric acid (HCl) upon the sulphides of the ore under treatment,
the use of the sulphuretted hydrogen (H,S) so obtained as fuel and the subsequent
utilisation of the sulphur dioxide (SO) resulting from the combustion of this fuel
for the treatment of sodium chloride to produce fresh supplies of gaseous hydro-
chloric acid (HCI) for use in the disintegration of ore.
6. In the treatment of argentiferous sulphide ores the herein described process
consisting in obtaining sulphur dioxide (SU₂) by the combustion of sulphuretted
hydrogen (H,S) resulting from the action of gaseous hydrochloric acid (HCI)
upon the sulphides of the ore under treatment, subsequently treating sodium
chloride by the sulphur dioxide (SO2) so obtained for the formation of gaseous
hydrochloric acid (HCI), subsequently treating with the gaseous hydrochloric
acid (HCI) thus. obtained salt brine taken from the last of the series of lixiviating
tanks whereby aqueous hydrochloric acid (HCI) is obtained and sodium chloride is
recovered for renewed use during the process.
7. In the treatment of galena and argentiferous. galena the modified process
herein described consisting in ipouring the raw ore in a finely divided state either

page_text: alone but preferably mixed with lead sulphate and lead oxide into a bath of fused
zinc chloride whereby the lead is thrown down as metallic lead and the silver
chloride with the gangue becomes admixed with the fused chloride of zinc, the
fused mass being subsequently removed for the recovery of the silver and zinc in
the manner as herein before described.
Dated thin 7th day of Datcha 1896
ABEL & IMRAY,
Agents for the Applicant.