Year: 1894

page_text: Date of Application, 16th June, 1894
Complete Specification Left, 18th Mar., 1895-Accepted, 20th Apr., 1895
The solution of ZnCl, is enriched by the known methodical way, then relieved
of any metals that are more electronegative than zinc, and electrolysed in an
apparatus fitted with insoluble anodes.
On the cathodes pure metallic zinc is deposited, while on the anodes chlorine is
set free, which may be utilized for producing chlorate of potash or bleaching
powder, or for the extraction of metals, or for other purposes.
As it is not convenient, to precipitate by electricity all the zinc contained in the
solution or extracted in this manner, I precipitate the last portion by means of
hydrated lime Ca(OH)2, thereby obtaining Zn(OH)2, which may be utilized in
any suitable manner. For the extraction of zinc as described above, I preferably
use the cheap solutions of chloride of calcium that are obtained as a by-product in
the manufacture of ammonia-soda or of chlorate of potash. Neither common
salt nor compounds of potassium can do any harm in the solution to be electrolysed.
To avoid unnecessary waste of the solutions in the exhausted minerals, these
latter are conveniently washed with pure water or with weak solutions that may be
enriched methodically. All weak solutions are conveniently concentrated in
a boiler, and the produced steam may be utilised for working an engine or other
industrial contrivance.
By this method the common salt and the compounds of potassium contained in
the original solutions are recuperated and utilised, and the steam generated by the
concentration of solutions can be utilised too.
The common salt and chloride of potassium contained in the solution may also be
utilised by decomposing them with sulphate of zinc into chloride of zinc and
sulphate of alkali.
Sometimes for the extraction of zinc ores, especially calamine, I also make use
of solutions of carnallite containing chloride of potassium and chloride of magnesium,
which solutions may be mixed with hydrated lime Ca(OH)2, thus producing
CaCl, and MgO. The KCI contained therein may then be used for the production
of chlorate of potash.
Dated this 16th day of June 1894.

page_text: Improvements in the Treatment of Calamine and similar Minerals:
or Compounds for the Extraction of Zinc.
I, CARL HOEPFNER, of 36 Frankfurterstrasse, Giessen, in the Empire of
Germany, temporarily of the Grand Hotel, London, 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 has for its object, the economical extraction of zinc from its
carbonate (artificial or natural) or materials containing the same and especially
from calamine.
For this purpose a solution of calcium chloride, sufficiently concentrated and
heated, is mixed with finely powdered carbonate of zinc or calamine, preferably at
high pressure, in a boiler or retort. Such pressure may be produced by means of
any compressed gas.
The carbonate of zinc is thereby dissolved or extracted and the solution of
calcium chloride partly replaced by ZnCl。.
The solution of ZnCl, is enriched by the known method then relieved of any
metals that are more electronegative than zinc, and electrolysed in an apparatus
fitted with insoluble anodes.
On the cathodes pure metallic zinc is deposited, while at the anodes chlorine is
set free which may be utilized for producing chlorate of potash or bleaching powder,
or for the extraction of metals or for any other purpose.
As it is not convenient, to precipitate by electricity all the zinc contained in the
solution or extracted in this manner, I precipitate the last portion chemically,
preferably by means of hydrated lime Ca(OH), thereby obtaining Zn(OH),
which may be utilized in any suitable manner. For the extraction of zinc as
described above I preferably use the cheap solutions of calcium chloride, that are
obtained as a by product in the manufacture of ammonia soda or of chlorate of
potash. Neither common salt nor compounds of potassium can do any harm in the
solution to be electrolysed.
For the purpose of preventing the loss of too great a quantity of the solutions in
the exhausted minerals, these latter are conveniently washed with pure water or
with weak solutions, that may be enriched methodically. All weak solutions are
conveniently concentrated in a boiler and the produced steam may then be utilized
for working an engine or other industrial contrivance.
By this method, the common salt and the compounds of potassium contained in
the original solutions are recuperated and utilized, and the steam generated by the
concentration of solutions can be utilized too.
The common salt and chloride of potassium contained in the solution may also
be utilized by decomposing them with sulphate of zinc into chloride of zinc and
sulphate of alkali. This reaction may be completed by refrigeration of the
solution or cooling down the same, whereby the sulphate of alkali is crystallized
out.
For the extraction of zinc from carbonate of zinc especially calamine, I sometimes
also make use of solutions of carnallite containing chloride of potassium and chloride
of magnesium or of other solutions of chloride of magnesium, which solutions
may be mixed with hydrated lime Ca(OH),, thus producing CaCl, and MgO,

page_text: which is separated from the liquid. The KCl contained therein for instance in
carnallite may then be used for the production of chlorate of potash.
If artificial carbonate of zinc, as before mentioned, is to be treated, it will be
proceeded in a similar sense as with calamine. Such artificial carbonate of zinc
can be obtained in any way and from any zinciferous material, as for instance by
the action of carbonic acid on oxide of zinc either free or in basic solution.
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 process for the treatment of carbonate of zinc or of materials, containing
the same characterized by treating such carbonate of zinc or such materials by
means of solutions, containing calcium chloride at an elevated temperature and
under pressure.
2. The process for the extraction of zinc from carbonate of zinc or from
materials containing the same by treating such carbonate or such materials
according to the process characterized in Claim 1 and then electrolysing the
zinciferous solution so obtained.
3. The process of extracting zinc from carbonate of zinc or from materials
containing the same according to Claim 2, whereby only a part of the zinc is
deposited by electrolysis whilst the rest is chemically precipitated preferably by
the addition of lime to the solution partially electrolyzed.
4. In the processes characterized in Claims 1 to 3 the employment of solutions
containing calcium chloride especially as obtained in the manufacture of ammonia
soda or of chlorate of potash or obtained from solutions, containing magnesium
chloride, for instance carnallite, by the addition of lime to such solutions.
In the processes above characterized the concentration of weak solutions by
heating the same in a boiler or vessel and utilizing the steam thereby produced for
working an engine or other industrial contrivance.
6. In the processes above characterized the concentration of the solutions by
evaporation so as to recuperate salts, contained therein, especially the common salt
or compounds of potassium.
1002
HASELTINE, LAKE & Co..
45, Southampton Buildings, London, W.C., Agents for the Applicant.