Improvements in the Production of Zinc Chlorides.
Year: 1895

page_text: Date of Application, 18th Mar., 1895
Complete Specification Left, 18th Dec., 1895-Accepted, 18th Jan., 1896
PROVISIONAL SPECIFICATION.
Improvements in the Production of Zinc Chlorides.
I, CARL HOEPFNER, of 36 Frankfurterstrasse, Giessen in the Empire of
Germany, Doctor of Philosophy, do hereby declare the nature of this invention
to be as follows:-
This invention relates to the production of zinc chloride from zinc oxide or
any substance or substances containing zinc oxide in the free state. Of these
roasted zinc ores such as calamine and zinc blende are the most important.
According to my said invention I treat these substances, finely comminuted,
with a solution of magnesium chloride or zinc chloride in which the zinc oxide
is soluble. The basic solution so obtained is converted into neutral zinc chloride
solution.
For this purpose I treat it with carbon dioxide when zinc carbonate is
precipitated, which I convert into zinc chloride by treatment with calcium
chloride as described in the Specification of my prior Patent No. 11724 June 16,
1894. The magnésium chloride or the zinc chloride solution respectively can
thus be used over and over again.
In some cases instead of magnesium chloride and zinc chloride other neutral
chlorides can also be profitably used, for instance chloride of iron and of ammonia.
Or I treat the zinc oxide or substance or substances containing the same with the
solution of a mixture of calcium chloride with maguesium chloride or zinc chloride
or any other neutral chloride capable of dissolving zinc oxide and at the same
time or subsequently with carbonic dioxide. Zinc chloride goes into solution
and calcium carbonate is precipitated.
The solution containing zinc chloride, calcium chloride and possibly also
magnesium chloride or other chlorides is purified from metals more electronegative
than zinc and then subjected to electrolysis until the zinc or the greater part
of it is separated out and its equivalent of chlorine given off (as described in
a previous Patent No. 13336 July 8th 1893) the solution then remaining is used
after adding the necessary amount of calcium chloride or after reconcentrating
it in some other way for acting on a fresh quantity of zinc oxide.
In some cases I treat zinc oxide or substances containing the same with a strong
solution of chloride of calcium and at the same time with carbon dioxide, when
the zinc chloride goes into solution and calcium carbonate is precipitated.
Neither the solutions of zinc chloride, magnesium chloride, calcium chloride,
nor the carbon dioxide used in this process for the extraction of zinc oxide need
be pure, and any by-products of other manufactures containing these substances
in sufficient quantity can be used.
Among these the most available are the residual liquors of the manufacture
of potassium chloride (containing magnesium chloride) the liquors of the manu-
facture of potassium chlorate, the liquors of the manufacture of soda by the
ammonia process (containing calcium chloride) and finally also the liquors resulting
from the extraction of metals such as copper and nickel from ores which contain
magnesia or calcium, which liquors can also contain chloride or more conveniently
perchloride of iron.
The necessary chloride of calcium can also be prepared from chloride of
magnesium and other metals by caustic lime. The carbon dioxide can be taken
from lime kilns and ordinary furnaces.

page_text: The zinc oxide may be extracted by a solution of caustic soda or potash or
ammonia or their carbonates and precipitated again from these solutions by carbon
dioxide as a carbonate which is then converted into chloride of zinc as heretofore
described. The alkaline solutions can then be used over and over again.
The operations described are expedited by heating the liquors by acting with
gas under pressure and by using suitably agitating grinding and mixing apparatus.
The temperatures, concentration and pressures required vary with the different
materials and have to be ascertained by experience.
In some cases this process which enables us to utilize in an excellent way the
solutions of chloride of calcium, magnesium, and other metals makes it possible to
use hydrochloric and also sulphuric acids for metallurgical and other purposes
where proportionately great quantities of cheap acid are required.
Available chlorides can be obtained from sulphates such as sulphate of iron
magnesium and other metals by the known reaction with chloride of sodium and
potassium at a low temperature.
Dated this 18th day of March 1895.
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Production of Zinc Chlorides.
I, CARL HOEPFNER, of 36 Frankfurterstrasse, Giessen, in the Empire of
Germany, 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 the production of zinc chloride from zinc oxide or any
substance or substances containing zinc oxide in the free state. Of these roasted
According to my said invention I treat these substances, finely comminuted,
with a solution of magnesium chloride or zinc chloride in which the zinc oxide is
soluble. The basic solution so obtained is converted into neutral zinc chloride
solution.
zine ores such as calamine and zinc blende are the most important.
For this purpose I treat it with carbon dioxide when zinc carbonate is precipitated,
which I convert into zinc chloride by treatment with calcium chloride as described
in the Specification of my prior Patent No. 11724 June 16, 1894. The
magnesium chloride or the zinc chloride solution respectively can thus be used
over and over again.
In some cases instead of magnesium chloride and zinc chloride also their
sulphates or other neutral chlorides or sulphates can be profitably used, for
instance chloride of iron and of ammonia. Or I treat the zinc oxide or substance
or substances containing the same with the solution of a mixture of calcium
chloride with magnesium chloride or zinc chloride or any other neutral chloride
capable of dissolving zinc oxide and at the same time or subsequently with carbonic
dioxide. Zinc chloride goes into solution and. calcium carbonate is precipitated.
The solution containing zinc chloride, calcium chloride and possibly also
magnesium chloride or other chlorides is purified from metals more electronegative
than zine and is then subjected to electrolysis until the zinc or the greater part of
it is separated out and its equivalent of chlorine given off (as described in a
previous Patent No. 13336 July 8th 1893) the solution then remaining is used
after adding the necessary amount of calcium chloride or after reconcentrating it.
in some other way for acting on a fresh quantity of zinc oxide.
Or the zinc chloride solution so obtained may be wholly or partly converted into
pure oxide of zinc or into pure sulphide of zinc and utilized as such.

page_text: In some cases I treat zinc oxide or substances containing the same with a strong
solution of chloride of.calcium and at the same time with carbon dioxide, when the
zinc chloride is formed and calcium carbonate is precipitated.
Neither the solution of zinc chloride, magnesium chloride, calcium chloride, nor
the carbon dioxide used in this process for the extraction of zinc oxide need be
pure, and any by-products of other manufactures containing these substances in
sufficient quantity can be used.
Among these the most available are the residual liquors of the manufacture of
potassium chloride (containing magnesium chloride) the liquors of the manufacture
of potassium chlorate, the liquors of the manufacture of soda by the ammonia
process (containing calcium chloride) and finally also the liquors resulting from
the extraction of metals such as copper and nickel from ores which contain
magnesium or calcium chloride and which may also contain protochloride or
perchloride of irou.
The necessary chloride of calcium can also be prepared from chloride of
magnesium and other metallic chlorides by caustic lime. The carbon dioxide can
be taken from lime kilus and ordinary furnaces.
The zinc oxide may also be extracted by a solution of caustic soda or potash or
ammonia or their carbonates and precipitated again from these solutions by
carbonic dioxide as a carbonate which is then converted into chloride of zinc as
described in a previous Patent. The alkaline solutions can then be used over and
over again.
The operations described are expedited by heating the liquors by acting with
gas under pressure and by using suitably agitating grinding and mixing apparatus.
The temperatures, concentration and pressures required vary with the different
materials and have to be ascertained by experience.
In some cases this process which enables us to utilize in an excellent way the
solutions of chloride of calcium, magnesium and other metals makes it possible to
use hydrochloric and also sulphuric acids for metallurgical and other purposes
where proportionately great quantities of cheap acid are required for instance in
the extraction of some ores containing copper or nickel.
Available chlorides can be obtained from sulphates such as sulphate of iron,
magnesium and other metals by the known reaction with chloride of sodium
and potassium at a low temperature.
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. In the production of chloride of zinc the treatment of materials containing
oxide of zinc by liquids (such as solutions of chlorides or alkalies) capable of
dissolving oxide of zinc so as to produce basic solutions of zinc from which.
solutions the zinc is precipitated in the form of carbonate of zinc preferably by
means of carbonic acid (pure or impure), separating such carbonate of zine from
the solution and converting it into chloride of zinc.
2. In the process characterized in Claim the production of solutions of
chloride of zinc by the treatment of materials containing oxide of zinc by liquids
capable of dissolving this oxide and containing also chloride of calcium and by
subsequently or simultaneously treating the solution thus obtained with carbonic
acid, so as to precipitate carbonate of calcium instead of carbonate of zinc and to
directly obtain a solution of chloride of zinc.
3. The production of zinc chloride by treating oxide of zinc or substances
containing the same simultaneously with a solution containing calcium chloride and
with carbon dioxide.
4. For the processes characterized in Claims 1 and 2 the employment and
utilization of waste or residual solutions containing chloride of magnesium or
calcium or other chlorides or sulphates which solutions may be derived from the

page_text: extraction of ores or from other industrial processes such as the manufacture
of alkali by the ammonia process.
5. For the process described in Claims 1-3 the employment of sulphate
solutions by previously converting the same into chloride solutions by treating
such sulphate solutions by means of chloride of alkaline metals at low temperature,
so as to obtain a chloride solution to be used for dissolving oxide of zinc in the
processes above described.
Dated this 18th day of Deanmhan 1005
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.