Improvements in the Electrolytic Treatment of Copper and Silver Ores.
Year: 1891

page_text: Date of Application, 16th Dec., 1891
Complete Specification Left, 9th Sept., 1892-Accepted, 10th Dec., 1892
PROVISIONAL SPECIFICATION.
Improvements in the Electrolytic Treatment of Copper and Silver
Ores.
I, CARL HOEPFNER, of Giessen, in the Empire of Germany, do hereby declare
the nature of this invention to be as follows :-
In the treatment of copper and silver ores the quantity of iron contained in the
materials has been found to cause inconveniences.
These are to be obviated according to my invention by removing the iron as
much as practicable from the ferriferous liquors or ores as hereinafter described.
In the lixiviation of copper and silver ores by cupric chloride part of the iron
contained in the ore is always dissolved. Now when such a liquor, which contains
the chloride by reason of the action of the same as cuprous chloride, is subjected to
electrolysis and the cuprous chloride is thereby converted again into cupric chloride,
the liquor of cupic chloride obtained and to be used again for the lixiviation will be
liable on account of too great a quantity of iron to become deficient for the
lixiviation and the cycle will be gradually disturbed.
To obviate disturbances in such an electrolytic cycle, the iron must be removed
from the liquors with regeneration of the cupric chloride employed for its
dissolution, which has thereby become cuprous chloride.
This is effected either indirectly by the addition of alkalies, alkaline earths, or
their carbonates, whereupon the precipitate produced is by filtration or otherwise
separated from the clear liquor, the latter being acidified and oxidized by means of
oxygen or else directly by treatment of the neutral ferriferous liquor with oxygen
or air, which may take place by the introduction of oxygen or air into the respective
solution, or with cuprous oxychloride, iron oxide being precipitated and the
equivalent quantity of cuprous chloride being transformed into cupric chloride.
This reaction through the medium of oxygen by itself or oxygen of the air or of
the cuprous oxychloride may be represented by the following formula :-
For effecting the lixiviation of roasted argentiferous or cupreous ores, more
especially burnt iron pyrites, it may be advantageous to remove from the solid
material as completely as possible at least the iron contained therein as a molten
iron sulphide prior to the lixiviation.
This is achieved by magnetic separation effected simultaneously with the
grinding, in such a manner that, for ensuring as complete as practicable a removal
of the iron sulphide, the material is repeatedly subjected in the various stages of
the disintegration to a magnetic separating action or conveyed past magnetic
separators.
Dated this 16th day of December 1891.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.

page_text: COMPLETE SPECIFICATION.
Improvements in the Electrolytic Treatment of Copper and Silver
Ores.
I, Dr. CARL HOEPFNER, of Giessen, in the Empire of Germany 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:--
In the treatment of copper and silver ores or mattes the quantity of iron contained
in the materials has been found to cause considerable inconvenience.
According to the present invention I obviate the aforesaid inconvenience by
removing the iron as much as practicable from the ferriferous liquors or ores as
hereinafter described.
In the lixiviation of copper and silver ores or mattes by cupric chloride such as
described in a former Specification No. 4626 of 1888, part of the iron contained in
the ore is always dissolved. Now when such a liquor, which contains the chloride
by reason of the action of the same as cuprous chloride, is subjected to electrolysis
and the cuprous chloride is thereby converted again into cupric chloride, the
liquor of cupric chloride obtained and which is to be used again for the lixiviation
will on account of too great a quantity of iron, be liable to become deficient for the
lixiviation and the cycle will be gradually disturbed.
To obviate disturbances in the aforesaid continuous process the iron must be
removed from the liquors with regeneration of the cupric chloride employed for its
dissolution.
This is effected either indirectly by the addition of alkalies, alkaline earths, or
their carbonates, where upon the precipitate produced is by filtration or otherwise
separated from the clear liquor, the latter being acidified and oxidized by means of
oxygen, or else directly by treatment of the neutral ferriferous liquor with oxygen
or air, which may take place by the introduction of oxygen or air into the
respective solution, or with cuprous oxychloride, iron oxide being precipitated and
the equivalent quantity of cuprous chloride being transformed into cupric chloride.
This reaction through the medium of oxygen by itself or oxygen of the air or
of the cuprous oxychloride may be represented by the following formula.
2 (Cu,Cl₂) + 2 (FeCl₂) + 30 =4 (CuCl,) + FeO..
I proceed as follows for carrying out the above described invention.
The cuprous chloride liquor obtained by the reaction of cupric chloride upon
raw or calcined (roasted) copper ores or mattes is mixed in a suitable apparatus or

page_text: 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 :-
In the treatment of copper and silver ores, the entire or partial removal of the
iron from the solutions obtained in the direct electrolytic lixiviation such as
described in the Specification 4626 of 1888 of such ores either indirectly by
precipitating the same by means of alkalies, alkaline earths or their carbonates with
subsequent regeneration of the cupric chloride employed for its dissolution by
oxygen and acid, or by the treatment of the neutral ferriferous solutions of cuprous
chloride with oxygen, air or cuprous oxychloride.
Dated this 9th day of September 1892.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.