Year: 1888

page_text: This Specification was, upon the 15th day of February 1892, Amended under
Sections 18 to 21 of the Patents, Designs, and Trade Marks Act, 1883.
I, CARL HOEPFNER, of Berlin, in the German Empire, Doctor of Philosophy do
hereby declare the nature of this invention to be as follows:-
This invention relates to processes for obtaining metals, in particular copper, by
electrolysis, whereby a greater yield of metal is obtained with a much smaller
expenditure of precipitating iron or of electrical power employed for effecting the
precipitation, than with the processes now employed.
These advantages are mainly obtained by producing and employing the copper
protoxide salts in place of the copper oxide salts heretofore used for electrolysis.
The process is as follows:-
:-
For the preparation of the lyes to be subjected to the electrolytic process, chloridised
roasted waste ores are treated with a concentrated solution of common salt or of other
suitable chlorides (which can always be used over again) until the greater part of the
copper is extracted.
The remainder, if any, is extracted and rendered available by any suitable means
such as by hydrochloric acid.
The glauber salts contained in the waste ores that are not dissolved by the common
salt, are obtained by lixiviation with water.
In the salt lyes is contained the copper in the form of chloride, and this is con-
verted into protochloride, which is effected by bringing the lyes in contact with non
chloridised waste ore or other products of orc smelting that contain metals or
sulphides thereof (in particular sulphide of copper), protochloride of copper is then
forined under separation of sulphur.

page_text: Tin is precipitated as oxide, arsenic, as arseniate; silver and gold are then
precipitated by iron or copper.
The impurities and precious metals having been removed, the protochloride lye is
subjected to electrolytic action with carbon electrodes. As the solution has very good
conducting power and the polarisation at the carbon pole is removed by the oxidation
of the protochloride of copper present, and as moreover the quantity of the
separated copper is double that obtained by the electrolysis of copper oxide salts, it
is possible by this process to obtain about 40 kilogrammes of electrolytic copper per
horsepower in 24 hours.
At the positive carbon pole which is generally separated from the cathode by
means of a membrane of parchment paper, the cuprous chloride is converted into
cupric chloride.
When this conversion has been completely effected, free chlorine is formed which
combines with the sulphate contained in the lye to form subchlorous acid.
For the extraction of copper from its ores the presence of cupric chloride is
sufficient.
When gold, silver, and metallic sulphides that dissolve with difficulty, are present,
it suffices to let the cupric chloride salt lye remain longer at the anode, until free
chlorine or subchlorous acid is formed.
This highly oxidized liquid can be used for further lixiviations. The chlorine
required for this purpose can of course be obtained from any chlorides. Instead of
the ordinary parchment paper, which does not withstand the action of free chlorine,
may be used a membrane of nitrated cellulose.
The production of chlorine should generally be avoided. This is effected either by
a constant supply of fresh cuprous chloride lye or of ferrous chloride lye, to the
carbon pole, while the oxidized lye is regenerated outside the bath by means of
sulphurous acid, metallic sulphides (sulphide of copper) or metals, such as cement
copper.
The reduction of the cupric chloride is effected most easily and rapidly by means
of cement copper which is obtained from cupric chloride lyes, or, more economically,
from the cuprous chloride lyes obtained as above, by means of iron. 56 kilos of iron
precipitate 126 kilos of copper.
When iron is high in price, the copper sponge is produced as follows:-
From cupric or cuprous chloride lyes copper oxide or protoxide is precipitated by
lime. These are then reduced by carbon or carbonic oxide &c., the chloride of calcium
being, if requisite, separated from the lyes by means of glauber salts. The necessary
reduction of the cupric chloride formed at the anode to cuprous chloride is generally
effected outside the bath, but can also be effected within it by suspending copper
sponge or sulphide of copper in the bath. In this case the use of a membrane between
the two poles is not necessary.
In those smelting works in which black copper is to be refined, the refining is not
effected as heretofore by means of the expensive solution of sulphuric acid and copper
vitriol, but with the above described cuprous chloride lye. This remains neutral and
therefore permits of the separation therefrom of arsenic &c. without cost. In addition,
the refining takes place more than twice as quick with this lye.
Both for the movement of the electrolytic lye in the baths and for facilitating the
lixiviation of powdered ores, it is necessary to set the liquids in motion by means of
gases free from oxygen.
This is effected by causing hot combustion gases to pass over incandescent charcoal
so as to part with their oxygen, and then, either with or without previous cooling,
forcing them into the liquid.
It is desirable for the movement of the electrolyte that the gases should contain
carbonic oxide.
The depolarisation is aided by the chemical combination of this gas with the
cuprous chloride. The cupric chloride lyes, which, for the purpose of lixiviation or
reduction by means of ores containing sulphide of copper, are best heated, may be
conveniently and cheaply heated by blowing through them hot combustion gases.

page_text: The above described neutral lixiviating and precipitating process, which is capable
of many modifications, offers the following advantages
1. Less than half the usual quantity of precipitating iron is required.
2. Half the quantity of common salt ordinarily used is saved because only half the
ore requires to be chloridised in roasting.
3. The obtaining of glauber salt, or the regaining of nearly the whole of the
common salt used is rendered possible by the fact that the copper is precipitated by
lime as oxide or protoxide, the common salt being regenerated by the conversion of
the solutions of Cu, and Na 2 SO. This is of course of great importance for
countries in which salt is scarce.
4. The purification of the neutral electrolytic lye is very easy and consequently
the quality of the copper is faultless.
For the preparation of cement-copper from copper solutions I employ by
preference tinplate waste, where this is to be had. This dissolves and affords a
cement copper containing tin. The electrolytic refined copper is deprived of its tin
by the above described process and the tin can be readily gained from the lyes by the
known methods.
Dated this 26th day of March 1988.
ABEL & IMRAY,
Agents for the Applicant.

page_text: I, CARL HOEPFNER, of Berlin, in the German Empire, Doctor of Philosophy, do
hereby declare the nature of this invention and in what manner the same is
to be performed to be particularly described and ascertained in and by the following
statement:-
This invention relates to processes for obtaining metals, in particular copper by
electrolysis, whereby a greater yield of metal is obtained with a much smaller expendi-
ture of electrical power employed for effecting the precipitation than with the processes
now employed.
These advantages are mainly obtained by producing and employing the copper
protoxide salts in place of the copper oxide salts heretofore used for electrolysis.
The process is as follows:
For the preparation of the lyes to be subjected to the electrolytic process,
chlorinated roasted waste orcs are treated with a concentrated solution of common
salt or of other suitable chlorides (which can always be used over again) until the
greater part of the copper is extracted.
In the salt lyes the copper is contained in the form of chloride, and this is con-
verted into protochloride which is effected by bringing the lyes in contact with
metals such as copper, iron, &c. sulphurous acid, non chlorinated waste-ores, or other
ores or products of ore smelting that contain metals or sulphides thereof (in
particular sulphide of copper); protochloride of copper is then formed under 2
separation of sulphur.
The protochloride formed is maintained in solution by means of the salt.
The neutral protochloride lye thus obtained may be readily freed from any impuri-
ties by adding sulphur compounds of the alkalis or oxides or carbonates of the alkalis
either in solid or liquid form.
Tin is precipitated as oxide, arsenic as arseniate, silver and gold are then precipitated
by iron or copper, or by electrolysis.
The impurities and precious metals having been removed, the protochloride lye is
subjected to electrolytic action with carbon electrodes. As the solution has
very good
conducting power and the polarisation at the carbon pole is removed by the oxidation
of the protochloride of copper present, and as moreover the quantity of the deposited
copper is double that obtained by the electrolysis of copper oxide salts it is possible
by this process to obtain about 40 kilogrammes of electrolytic copper per horse power
in 24 hours.
At the positive carbon pole which is generally separated from the cathode by
means of a membrane of parchment paper, the cuprous chloride is converted into
cupric chloride.

page_text: For the extraction of copper, lead and silver from their ores the presence of cupric
chloride generally is sufficient.
However if there is gold to be extracted, I make this cupric chloride salt lye remain
longer at the anode. Therefore when all the cuprous chloride has been converted
into cupric chloride, and all the chloride of iron existing in the lye has been converted
into perchloride of iron, free chlorine must be formed which may be used to extract
the gold also.
If there be any sulphate in the lye, the free chlorine formed combines with this
sulphate forming subchlorous acid.
The production of chlorine should generally be avoided. This is effected by a
constant supply either of fresh cuprous chloride lye or of ferrous chloride lye to
the anode, while the oxidised lye is regenerated within-or outside the bath by means
of reducing gases and liquids such as-sulphurous acid, protechloride-of-tin, and the
like, or by metallic sulphides (sulphide of copper) or metals such as cement-copper,
iron, zine, lend &c.
The reduction of the cupric chloride is effected most easily and rapidly by means of
cement-copper which is obtained from cupric chloride lyes, or more economically
from the cuprous chloride lyes obtained as above by means of iron. 56 kilos of iron
precipitate 126 kilos of copper.
When iron is high in price, the copper sponge is produced as follows+-
From enprie or cuprous chloride lyes copper oxide of copper protoxide is precipitated
by lime. These are then reduced by carbon or carbonic oxide-&e, the chloride of
enleinm being if required, separated from the lyes by means of glanber-salts.
The necessary reduction of the cupric chloride formed at the anode to cuprous
chloride is generally effected outside the bath but can also be effected within it by
suspending copper sponge or sulphide of copper in the bath.
In this case the use of a membrane between the two-poles-is-not necessary.
Instead of using carbon anodes in some cases-may be used such containing-iron or
copper. In those smelting works for instance, in which black copper is to be
refined, the refining is not effected-as-heretofore-by-means-of-the-expensive-solution
of sulphuric acid and copper vitriol, but instead of these I-use-a lye-containing
euprous chloride as above described, employing black copper or mattes of copper as
anodes. This lye remains nearly neutral and therefore-permits-of-the-separation
therefrom of arsenic &e. without cost. In addition, the refining takes place more than
twice as quick-with-this-lye.
Both for the movement of the electrolytic lye in the baths and for facilitating the
lixiviation of powdered ores it is advantageous to set the liquids in motion by means
of gases free from oxygen.
This is effected by causing hot combustion gases to pass over incandescent
charcoal so as to part with their oxygen and then, either with or without previous
cooling, forcing them into the liquid. It is at the same time advantageous for the
further operations and for movement of the electrolyte that the gases should contain
carbonic oxide. The depolarisation is aided by the chemical combination of this gas with
the cuprous chloride. The cupric chloride lyes which, for the purpose of lixiviation or
reduction by means of ores containing sulphide of copper, are best heated, may be
conveniently and cheaply treated by blowing through them hot combustion gases.
Instead of using chloride salt lyes, of course also bromide or iodide salt lyes may
be employed.
The herein before described process for the electrolytic production of metals is
applicable with particular advantage to copper ores that contain silver, and even
ores that are poor in copper or that contain no copper can be operated upon
thereby.
The silver is particularly readily soluble in the electrolytic oxidised lye produced
at the insoluble anode. From the protochloride lye produced by contact with the

page_text: ores the silver can then readily be precipitated before the copper by electrolysis or it
may be separated by cementing with metallic copper, lead &c. or be precipitated by
iodides.
For the purpose of extracting lead in the same way, the extraction lyes are heated;
on cooling, the lead separates of itself.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. In the electrolytic production of copper the employment of cuprous chloride,
bromide, or iodide dissolved in a halogen salt lye or in hydro halogen acid, as electrolyte
with electrolytically soluble or insoluble anodes, substantially as herein described.
2. In the application of cuprous chloride lyes as set forth in the first claim for the
electrolytic production or refining of copper, the reduction of the copper and iron
perchlorides formed at the anode, either within or outside the electrolytic bath, by
either of the following means:
(a) metallic copper, sulphide of copper, heavy metals such as iron, lead, zine,
and the-like, or the sulphur compounds thereof.
(6) ores and the products of smelting works containing the substances mentioned
under (a).
(c)-reducing guses and liquids such as sulphuronas neid, protochloride of tin, and
the like.
3. The application of the electrolytic process referred to in the first claim :-
(a) to the extraction of silver in such manner that by means of the solutions
of copper perchloride or iron perchloride in common salt or other lyes
that can dissolve chloride of silver or cuprous chloride and that are
formed electrolytically at the insoluble anode, the silver is dissolved from the
ores and is then separated from the solution either electrolytically or
chemically.
(b) to the extraction of lead with the use of heated lye from which the chloride
of lead precipitates of itself when cold.
Dated this 24th day of December 1888.
ABEL & IMRAY,
Agents for the Applicant.

page_text: Date of Application, 26th Mar., 1888
Complete Specification Left, 24th Dec., 1888
Complete Specification Accepted, 23rd Mar.; 1889
I, CARL HOEPFNER, of Berlin, in the Gorman Empire, Doctor of Philosophy do
hereby declare the nature of this invention to be as follows:-
This invention relates to processes for obtaining metals, in particular copper, by
electrolysis, whereby a greater yield of metal is obtained with a much smaller
expenditure of precipitating iron or of electrical power employed for effecting the
precipitation, than with the processes now employed.
These advantages are mainly obtained by producing and employing the copper
protoxide salts in place of the copper oxide salts heretofore used for electrolysis.
The process is as follows:-
For the preparation of the lyes to be subjected to the electrolytic process, chloridised
roasted waste ores are treated with a concentrated solution of common salt or of other
suitable chlorides (which can always be used over again) until the greater part of the
copper is extracted.
The remainder, if any, is extracted and rendered available by any suitable means
such as by hydrochloric acid.
The glauber salts contained in the waste ores that are not dissolved by the common
salt, are obtained by lixiviation with water.
In the salt lyes is contained the copper in the form of chloride, and this is con-
verted into protochloride, which is effected by bringing the lyes in contact with non
chloridised waste oro or other products of ore smelting that contain metals or
sulphides thereof (in particular sulphide of copper), protochloride of copper is then
formed under separation of sulphur.

page_text: Tin is precipitated as oxide, arsenic, as arseniate; silver and gold are then
precipitated by iron or copper.
The impurities and precious metals having been removed, the protochloride lye
subjected to electrolytic action with carbon electrodes. As the solution has very good
conducting power and the polarisation at the carbon pole is removed by the oxidation
of the protochloride of copper present, and as moreover the quantity of the
separated copper is double that obtained by the electrolysis of copper oxide salts, it
is possible by this process to obtain about 40 kilogrammes of electrolytic copper per
horsepower in 24 hours.
At the positive carbon pole which is generally separated from the cathode by
means of a membrane of parchment paper, the cuprous chloride is converted into
cupric chloride.
When this conversion has been completely effected, free chlorine is formed which
combines with the sulphate contained in the lye to form subchlorous acid.
For the extraction of copper from its ores the presence of cupric chloride is
sufficient.
When gold, silver, and metallic sulphides that dissolve with difficulty, are present,
it suffices to let the cupric chloride salt lye remain longer at the anode, until free
chlorine or subchlorous acid is formed.
This highly oxidized liquid can be used for further lixiviations. The chlorine
required for this purpose can of course be obtained from any chlorides. Instead of
the ordinary parchment paper, which does not withstand, the action of free chlorine,
may be used a membrane of nitrated cellulose.
The production of chlorine should generally be avoided. This is effected either by
a constant supply of fresh cuprous chloride lye or of ferrous chloride lye, to the
carbon pole, while the oxidized lye is regenerated outside the bath by means of
sulphurous acid, metallic sulphides (sulphide of copper) or metals, such as cement
copper.
The reduction of the cupric chloride is effected most easily and rapidly by means
of cement copper which is obtained from cupric chloride lyes, or, more economically,
from the cuprous chloride lyes obtained as above, by means of iron. 56 kilos of iron
precipitate 126 kilos of copper.
When iron is high in price, the copper sponge is produced as follows:-
From cupric or cuprous chloride lyes copper oxide or protoxide is precipitated by
lime. These are then reduced by carbon or carbonic oxide &c., the chloride of calcium
being, if requisite, separated from the lyes by means of glauber salts. The necessary
reduction of the cupric chloride formed at the anode to cuprous chloride is generally
effected outside the bath, but can also be effected within it by suspending copper
sponge or sulphide of copper in the bath. In this case the use of a membrane between
the two poles is not necessary.
In those smelting works in which black copper is to be refined, the refining is not
effected as heretofore by means of the expensive solution of sulphuric acid and copper
vitriol, but with the above described cuprous chloride lye. This remains neutral and
therefore permits of the separation therefrom of arsenic &c. without cost. In addition,
the refining takes place more than twice as quick with this lye.
Both for the movement of the electrolytic lye in the baths and for facilitating the
lixiviation of powdered ores, it is necessary to set the liquids in motion by means of
gases free from oxygen.
This is effected by causing hot combustion gases to pass over incan lescent charcoal
so as to part with their oxygen, and then, either with or without previous cooling,
forcing them into the liquid.
It is desirable for the movement of the electrolyte that the gases should contain
carbonic oxide.
The depolarisation is aided by the chemical combination of this gas with the
cuprous chloride. The cupric chloride lyes, which, for the purpose of lixiviation or
reduction by means of ores containing sulphide of copper, are best heated, may be
conveniently and cheaply heated by blowing through them hot combustion gases.

page_text: The above described neutral lixiviating and precipitating process, which is capable
of many modifications, offers the following advantages
1. Less than half the usual quantity of precipitating iron is required.
2. Half the quantity of common salt ordinarily used is saved because only half the
ore requires to be chloridised in roasting.
3. The obtaining of glauber salt, or the regaining of nearly the whole of the
common salt used is rendered possible by the fact that the copper is precipitated by
lime as oxide or protoxide, the common salt being regenerated by the conversion of
the solutions of Cu, and Na 2 SO. This is of course of great importance for
countries in which salt is scarce.
4'
4. The purification of the neutral electrolytic lye is very easy and consequently
the quality of the copper is faultless.
For the preparation of cement-copper from copper solutions I employ by
preference tinplate waste, where this is to be had. This dissolves and affords a
cement copper containing tin. The electrolytic refined copper is deprived of its tin
by the above described process and the tin can be readily gained from the lyes by the
known methods.
Dated this 26th day of March 1888.
ABEL & IMRAY,
Agents for the Applicant.

page_text: 1, CARL HOEPFNER, of Berlin, in the German Empire, Doctor of Philosophy, do
hereby declare the nature of this invention and in what manner the same is
to be performed to be particularly described and ascertained in and by the following
statement :-
This invention relates to processes for obtaining metals, in particular copper by
electrolysis, whereby a greater yield of metal is obtained with a much smaller expendi-
ture of electrical power employed for effecting the precipitation than with the processes
now employed.
These advantages are mainly obtained by producing and employing the copper
protoxide salts in place of the copper oxide salts heretofore used for electrolysis.
The process is as follows:
For the preparation of the lyes to be subjected to the electrolytic process,
chlorinated roasted waste ores are treated with a concentrated solution of common
salt or of other suitable chlorides (which can always be used over again) until the
greater part of the copper is extracted.
In the salt lyes the copper is contained in the form of chloride, and this is con-
verted into protochloride which is effected by bringing the lyes in contact with
metals such as copper, iron &c. sulphurous acid, non chlorinated waste-ores, or other
ores or products of ore smelting that contain metals or sulphides thereof (in
particular sulphide of copper); protochloride of copper is then formed under
separation of sulphur.
The protochloride formed is maintained in solution by means of the salt.
The neutral protochloride lye thus obtained may be readily freed from any impuri-
ties by adding sulphur compounds of the alkalis or oxides or carbonates of the alkalis
either in solid or liquid form.
Tin is precipitated as oxide, arsenic as arseniate, silver and gold are then precipitated
by iron or copper, or by electrolysis.
The impurities and precious metals having been removed, the protochloride lye is
subjected to electrolytic action with carbon electrodes. As the solution has very good
conducting power and the polarisation at the carbon pole is removed by the oxidation
of the protochloride of copper present, and as moreover the quantity of the deposited
copper is double that obtained by the electrolysis of copper oxide salts it is possible
by this process to obtain about 40 kilogrammes of electrolytic copper per horse power
in 24 hours.
At the positive carbon pole which is generally separated from the cathode by
means of a membrane of parchment paper, the cuprous chloride is converted into
cupric chloride.

page_text: Cl2 + 2 Na, SO, + H2O = 2 Na H SO, + Na O Cl + Na Cl.
4
The production of chlorine should generally be avoided. This is effected by a
constant supply either of fresh cuprous chloride lye or of ferrous chloride lye to
the anode, while the oxidised lye is regenerated within or outside the bath by means
of reducing gases and liquids such as sulphurous acid, protochloride of tin, and the
like, or by metallic sulphides (sulphide of copper) or metals such as cement-copper,
iron, zinc, lead &c.
The reduction of the cupric chloride is effected most easily and rapidly by means of
cement-copper which is obtained from cupric chloride lyes, or more economically
from the cuprous chloride lyes obtained as above by means of iron. 56 kilos of iron
precipitate 126 kilos of copper.
When iron is high in price, the copper sponge is produced as follows:-
From cupric or cuprous chloride lyes copper oxide of copper protoxide is precipitated
by lime. These are then reduced by carbon or carbonic oxide &c., the chloride of
calcium being if required, separated from the lyes by means of glauber salts.
The necessary reduction of the cupric chloride formed at the anode to cuprous
chloride is generally effected outside the bath but can also be effected within it by
suspending copper sponge or sulphide of copper in the bath.
In this case the use of a membrane between the two poles is not necessary.
Instead of using carbon anodes in some cases may be used such containing iron or
copper. In those smelting works for instance, in which black copper is to be
refined, the refining is not effected as heretofore by means of the expensive solution
of sulphuric acid and copper vitriol, but instead of these I use a lye containing
cuprous chloride as above described, employing black copper or mattes of copper as
anodes. This lye remains nearly neutral and therefore permits of the separation
therefrom of arsenic &c. without cost. In addition, the refining takes place more than
twice as quick with this lye.
Both for the movement of the electrolytic lye in the baths and for facilitating the
lixiviation of powdered ores it is advantageous to set the liquids in motion by means
of gases free from oxygen.
This is effected by causing hot combustion gases to pass over incandescent
charcoal so as to part with their oxygen and then, either with or without previous
cooling, forcing them into the liquid. It is at the same time advantageous for the
further operations and for movement of the electrolyte that the gases should contain
carbonic oxide. The depolarisation is aided by the chemical combination of this gas with
the cuprous chloride. The cupric chloride lyes which, for the purpose of lixiviation or
reduction by means of ores containing sulphide of copper, are best heated, may be
conveniently and cheaply treated by blowing through them hot combustion gases.
Instead of using chloride salt lyes, of course also bromide or iodide salt lyes may
be employed.
The herein before described process for the electrolytic production of metals is
applicable with particular advantage to copper ores that contain silver, and even
ores that are poor in copper or that contain no copper can be operated upon
thereby.
The silver is particularly readily soluble in the electrolytic oxidised lye produced
at the insoluble anode. From the protochloride lye produced by contact with the

page_text: ores the silver can then readily be precipitated before the copper by electrolysis or it
may be separated by cementing with metallic copper, lead &c. or be precipitated by
iodides.
For the purpose of extracting lead in the same way, the extraction lyes are heated;
on cooling, the lead separates of itself.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what 1
claim is :-
:-
1. In the electrolytic production of copper the employment of cuprous chloride,
bromide, or iodide dissolved in a halogen salt lye or in hydro halogen acid, as electrolyte
with electrolytically soluble or insoluble anodes, substantially as herein described.
2. In the application of cuprous chloride lyes as set forth in the first claim for the
electrolytic production or refining of copper, the reduction of the copper and iron
perchlorides formed at the anode, either within or outside the electrolytic bath, by
either of the following means:
(a) metallic copper, sulphide of copper, heavy metals such as iron, lead, zinc,
and the like, or the sulphur compounds thereof.
(b) ores and the products of smelting works containing the substances mentioned
under (a).
(c) reducing gases and liquids such as sulphurous acid, protochloride of tin, and
the like.
3. The application of the electrolytic process referred to in the first claim :-
(a) to the extraction of silver in such manner that by means of the solutions
of copper perchloride or iron perchloride in common salt or other lyes
that can dissolve chloride of silver or cuprous chloride and that are
formed electrolytically at the insoluble anode, the silver is dissolved from the
ores and is then separated from the solution either electrolytically or
chemically.
(b) to the extraction of lead with the use of heated lye from which the lead
precipitates of itself when cold.
Dated this 24th day of December 1888.