Improvements in and relating to the Manufacture of Solutions of Zinc Chloride and other Metal Chlorides
Year: 1895

page_text: Date of Application, 29th Apr, 1895
Complete Specification Left, 28th Jan, 1896-Accepted, 25th Apr,
1896
PROVISIONAL SPECIFICATION
Improvements in and relating to the Manufacture of Solutions of
Zinc Chloride and other Metal Chlorides
1, 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
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In order to obtain solutions of zinc, more especially of chloide of zinc from
roasted zinc blende or mixed blende ores or from any other material containing
oxide or carbonate or sulphite of zinc (ZnSO₂) I proceed as follows
The raw material is powdered and roasted if necessary and then treated with
sulphurous acid (SO2 or H₂SO₁) so as to obtain sulphite of zinc in a solid state
or in solution
This sulphite of zinc is then
In the latter ca e it contains free sulphurous acid
decomposed by a solution of chloride of calcium or of magnesium or barium or
other suitable metals forming sulphites relatively insoluble in water or other
liquids as for example bisulphite of soda o potash insoluble in alcohol so as to
form chloride of zinc (ZnCl2) and sulphite of calcium (Cas0%) and the like
The former being soluble is easily extracted, the latter being insoluble is left in
the residue, wherefrom, if nece sary, it can be extracted by sulphurous acid or
other cids (sucn as carbonic acid) and be utilized for various industrial purposes
especially for the manufacture of wood pulp
In this case the chloride of calcium solution (CaCl2) may be taken from the
bleaching process residual liquors from which acter a suitable purification by
chemical and osmotic agents a concentiated solution of chloride of calcium can be
obtained
Suitable solutions of chloride of calcium may also be obtained from any other
source
Or a solution of sulphite or bisulphite of zinc (ZnSO3) is mixed with a solution
of chloride of calc um (CaCl2) (or of other suitable chlorides) and the free
sulphurous acid eliminated therefrom either by distillation or by addition of lime
or other suitable oxides, carbonates or other compounds, whereby the precipitation
of sulphite of calcium (CaSO,) takes place and chloride of zinc is left in solution
Or a solution of chloride of calcium or of other suitable metals, whose sulphites
are relatively insoluble is mixed with materials containing oxide or carbonate of
zinc and the whole mass in a special vessel is impregnated with sulphurous acid
Thereby the zinc is dissolved as chloide of zinc and the calcium chloride
transformed into sulphite of calcium (CaSO3) which can be kept in solution by
free sulphurous acid and is therefrom precipitated if the free sulphurous acid is
eliminated either by distillation or by suitable oxides oi carbonates
The solutions of chloride of zinc can then be subjected to electrolysis, furnishing
pure zinc and chlorine
For this purpose the solution is to be purified from sulphurous acid and sulphites
as well as of other metalliferous impurities
The sulphite of zinc (ZnSO₂) obtained as above described in order to transform
it into a chloride by means of a chloride of alkalı may also be exposed to warm
air or to oxygen or chlorine, preferably in statu nascendi or electrolytically and
thereby be transformed into sulphate which by mixing with common salt and the