Improvements in the Manufacture of Zinc Oxide.
Year: 1896

page_text: Date of Application, 20th Feb., 1896
Date of Application, 20th Feb., 1896
Complete Specification Left, 20th Nov., 1890-Accepted, 2nd Jan., 1897
PROVISIONAL, SPECIFICATION.
Improvements in the Manufacture of Zinc Oxide.
We, Professor Dr. WILHELM HAMPE, and Professor Dr. CARL SCHNABEL
both of the University of Clausthal, Germany do hereby declare the nature of this
invention to be as follows:-
Our invention relates to a discovery which we have made that if finely divided
and dried zinc sulphate be intimately mixed with finely divided carbon (preferably
in the form of wood charcoal) and the mixture be subjected to an even and
correctly gauged temperature of 650 degrees C. (as nearly as practicable) for a
time which may be roughly stated at two hours, more or less, the following reaction
takes place, viz. :-
ZnSO, CZnO + SO2 + CO.
This reaction is complete within a very small limit if the above conditions are
correctly observed so much so that if the correct quantity of carbon to satisfy the
above reaction be employed, vis. :-about 75% of the weight of the dried sulphate
and if the temperature be properly gauged the finished product is found to
contain 78% to 80% of zinc and only %% to 1% of sulphur as basic sulphate and
sulphide of zinc.
The substantial advantages of this method lie in the fact that :-.
1. A much lower temperature is required to obtain zinc oxide from zinc
sulphate than by any other means hitherto known and therefore the
operation is practical and cheap being hitherto expensive and practically
impossible commercially;.
2. Gases rich in SO, are produced which can be made directly into sulphuric
acid in lead chambers of comparatively small size;
3. The zinc oxide produced is very pure and practically free from all other
substances except a very small amount of sulphur and a minute quantity of
ash from the charcoal.
The zinc sulphate may be obtained from zinc ores such as blende or mixed
blende and galena by the use of sulphuric acid and the sulphuric acid can then be
reproduced from the SO, obtained by the process.
Dated this 20th day of February 1896.
A. M. & WM. CLARK,
53, Chancery Lane, London, Chartered Patent Agents.
Improvements in the Manufacture of Zinc Oxide.
We Professor Dr. WILHELM HAMPE and Professor Dr. CARL SCHNABEL.
both of the University of Clausthal, Hanover, 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:-
Our invention relates to a discovery which we have made that if finely divided

page_text: and dried zinc sulphate be intimately mixed with finely divided carbon (preferably
in the form of wood charcoal) and the mixture be subjected to an even and
correctly-gauged temperature of 660° C. (as nearly as practicable) for a time
which may be roughly stated at two hours, more or less, the following reaction
takes place, viz. :—
Corr cury-gang
which may be roughly stated at two hours, more or less, the following reaction
takes place, viz. :—
ZnSOC ZnO + SO2 + CO.
=
This reaction is complete within a very small limit if the above conditions are
correctly observed, so much so, that if the correct quantity of carbon to satisfy
the above reaction be employed, viz. :-about 75% of the weight of the dried
sulphate, and if the temperature be properly gauged, the finished product is found
to contain 78% to 80% of zinc and only % to 1% of sulphur as basic sulphate
and sulphide of zinc.
For the successful working of the process it is essential that the following
precautions be taken, viz. :-
(1) The zinc sulphate must be dried by which is meant, freed from water of
crystallization;
(2) The mixture of the finely divided and dried zinc sulphate with the finely
divided carbon must be intimate; and
(3) The temperature must be carefully regulated so as to be as nearly as
practicable 650° C.
The substantial advantages of this method lie in the fact that :-
1. A much lower temperature is required to obtain zinc oxide from zinc
sulphate than by any other means hitherto known and therefore the
operation is practical and cheap, being hitherto expensive and practically
impossible commercially;
2. Gases rich in SO, are produced which can be made directly into sulphuric
acid in lead chambers of comparatively small size;
3. The zinc oxide produced is very pure and practically free from all other
substances except a very small amount of sulphur and a minute quantity of
ash from the charcoal.
The zinc sulphate may be obtained from zinc ores such as blende or mixed
blende and galena by the use of sulphuric acid and the sulphuric acid can then be
reproduced from the SO, obtained by the process.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
The process for preparing zinc oxide consisting in subjecting an intimate mixture
of finely divided and dried zinc sulphate and finely divided carbon to an even and
correctly gauged temperature substantially as described.
Dated this 20th day of November 1896.*
A. M. & WM. CLARK,
53, Chancery Lane, London, Chartered Patent Agents.
A. M. & WM. CLARK,
53, Chancery Lane, London, Chartered Patent Agents.