Improved Process for Extracting Metals from Pyritic Ores by Treatment with Chlorine, and for Recovering the Chlorine.
Year: 1896

page_text: Date of Application, 17th June, 1896
Complete Specification Left, 22nd Feb., 1897-Accepted, 17th Apr., 1897
PROVISIONAL SPECIFICATION.
Improved Process for Extracting Metals from Pyritic Ores by
Treatment with Chlorine, and for Recovering the Chlorine.
Employed.
I, Dr. OSCAR FRÖLICH, of No. 5 Hohenzollern-strasse, Steglitz, near Berlin,
Germany, do hereby declare the nature of this invention to be as follows:-
Although chlorine has been used for extracting metals from ores, it has seldom
been used in a dry or nearly dry state, and when so used it has been applied only
either to roasted ores or to treatment of natural ores at a high temperature. Now
my invention relates to the recovery of metals from pyritic ores or ores containing
sulphur, which are not roasted, by treatment at ordinary temperature with chlorine
dry or only slightly moistened with certain solutions selected according to the nature
of the ore treated. The chlorine may be applied according to my invention in any
suitable apparatus, but if it should be desired to economise time and extent of plant,
the treatment may be effected in revolving barrels to which the chlorine is supplied
from stores of compressed chlorine or from electrolytic cells in which the chlorine is
recovered from the results of previous treatment. In all cases the ore to be treated
is finely pulverised, and the special treatment may be best illustrated by several
examples.
EXAMPLE I.
For extracting zinc from zinc blend, the chlorine is applied quite dry until no
more is absorbed by the pulverised ore. The chlorides formed are then dissolved by
mixing the treated ore with a moderate quantity of water, so as to obtain the chloride
solution in a moderately concentrated condition. The solution may be accelerated by
acidulating the water with hydrochloric acid or by dissolving salt in the water. The
solution is then treated electrolytically in a cell provided with insoluble anodes and
metallic cathodes, whereby metallic zinc is deposited, and the chlorine is liberated.
This chlorine may flow direct to the vessel in which a succeeding batch of ore is
treated, and as the chlorine thus liberated, except for a slight loss, is equivalent in
quantity to that which effected chlorination of the ore, the same chlorine may be
considered to circulate, for the treatment of successive quantities of ore, in a
continuous manner.

page_text: The solid residue is treated with hydrochloric acid giving solution of antimonious
chloride which is treated electrolytically for deposit of the antimony and recovery of
the chlorine. The liquid resulting from the washing may also be treated
electrolytically for deposit of gold, or the gold can be recovered by any known
chemical treatment.
EXAMPLE IV.
The antimony and gold ore of the preceding example may also be treated in the
following manner. The pulverised ore is moistened and then treated with chlorine.
The product is treated with a dilute solution of tartaric acid by which is obtained a
solution containing the antimony but no gold; this solution is electrolysed. The
solid residue after the treatment with tartaric acid is again moistened, chlorinated and
treated with water or dilute hydrochloric acid giving a solution containing the gold of
the ore which can be recovered in any known manner.
EXAMPLE V.
A pyritic ore containing gold and silver is moistened with hydrochloric acid and
then chlorinated. The product is treated with hydrochloric acid giving a solution
which, besides the common metals, contains almost all the gold and silver.
In electrolysing the solutions obtained as in the preceding examples, it is not always
expedient to carry on the process until the whole of the chlorine is recovered, as this
might involve greater cost for the electrical energy required than is the cost of the
unrecovered chlorine; moreover the electrolyte still containing chlorine and
compounds thereof may be utilised for moistening or washing fresh quantities of ore.
By suitable variations in the tension of the electrolytic current, various metals
contained in the electrolyte may be separately deposited, the precious metals first by
currents of low tension, and the common metals afterwards by currents of higher
tension.
Dated this 17th day of June 1896.
Dated this 17th day of June 1896.
ABEL & IMRAY,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improved Process for Extracting Metals from Pyritic Ores by
Treatment with Chlorine, and for Recovering the Chlorine
Employed.
I, Dr. OSCAR FROLICH, of No. 5, Hohenzollern-strasse, Steglitz, near Berlin,
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 :-
Although chlorine has been used for extracting metals from ores, it has seldom
been used in a dry or nearly dry state, and when so used it has been applied only
either to roasted ores or to treatment of natural ores at a high temperature. Now my
invention relates to the recovery of metals from pyritic ores, or ores containing
sulphur, which are not roasted, by treatment at ordinary temperature with chlorine
dry or only slightly moistened with certain solutions selected according to the nature
of the ore treated.
The chlorine may be applied according to my invention in any suitable apparatus,
but if it should be desired to economise time and extent of plant, the treatment may

page_text: compounds thereof may be utilised for moistening or washing-fresh quantities
of ore.
By suitable variations in the tension of the electrolytic current, various metals
contained in the electrolyte may be separately deposited, the precious metals first
by currents of low tension, and the common metals afterwards by currents of higher
tension.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is
1. The herein described process for extracting metals from pyritic ores by treating
the ores at ordinary temperature with chlorine, and dissolving the chlorides formed,
the ores being not roasted, being finely pulverised and being treated dry or very
slightly moistened with suitable liquids.
2. In carrying out the process set forth in the preceding claim, the recovery of
chlorine by electrolytic treatment of the solution obtained from the chlorinated ore.
Dated this 22nd day of February 1897.
ABEL & IMRAY,
Agents for the Applicant.