Improvements in the Manufacture of Red Oxide Paints.
Year: 1893

page_text: Date of Application, 13th Mar., 1893
Complete Specification Left, 13th Dec., 1893-Accepted, 13th Jan., 1894
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Red Oxide Paints.
I MICHEL NICHOLAS D'ANDRIA of 6 Frogmore Terrace Chester Road,
Stretford, in the County of Lancaster, Manufacturing Chemist, do hereby
declare the nature of this invention to be as follows:-
In the manufacture of red oxide paints from ferrous sulphate, a very high
temperature has to be employed in order to completely expel (or nearly so) all the
sulphuric acid contained in the ferrous salt, and this high temperature which has
also to be maintained for a long time, has a very deleterious influence upon the
shade of the red oxide paint finally obtained and also upon its physical properties
as a pigment.
I have found that by heating a mixture of equal weights or thereabouts of ferrous
sulphate and magnesium sulphate, the decomposition takes place with great ease
and at a much lower temperature than if the ferrous sulphate alone is treated. As
a consequence of the lower temperature at which the disassociation of the ferrous
sulphate is effected by my improved process, and of the fact that this process also
causes, (owing to the presence of the magnesium sulphate) the peroxide of iron to
be more finely divided, an oxide paint is obtained, which in brightness of shade,
and physical properties, is by far superior to the product obtainable by the old
process.
At the end of the operation the magnesium sulphate is recovered from the red
oxide by lixiviation, and can be used over and over again, although it appears that
a certain percentage of the magnesia enters into chemical union with the ferric
oxide, from which it cannot be extracted with water.
During the treating of my improved mixture, sulphuric and suphurous acid are
evolved, and I propose to conduct them by means of pipes into a sulphuric acid
chamber, or the sulphuric anhydride may be separated from the sulphurous acid, by
means of any suitable system of air or water cool condensers.
The sulphuric anhydride is thus obtained as a liquid, and the gases of sulphurous
acid, are conveyed either to a sulphuric acid chamber, or they may be converted to
any desired derivative of sulphurous acid.
Dated this 10th day of March 1893.
MICHEL N. D'ANDKIA.
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Red Oxide Paints.
I, MICHEL NICHOLAS D'ANDRIA, of 6 Frogmore Terrace, Chester Road,
Stretford, in the County of Lancashire, Manufacturing Chemist, do hereby
declare the nature of this invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement:—
This invention relates to the manufacture of red oxide paints or pigments from
ferrous sulphate. In the manufacture of such paints or pigments as at present
conducted, it is necessary to use a high temperature in order to ensure the expulsion
of the sulphuric acid from the ferrous salt, and it is found that this high temperature
has a deleterious influence upon the shade of the product and upon its physical
character. My object is, by these improvements, to avoid these defects, and for

page_text: this purpose I mix magnesium sulphate with the ferrous sulphate, preferably in
about equal weights, and heat the mixture by similar means to those at present
employed when ferrous sulphate alone is used. By employing this mixture it is
found that a lower temperature suffices, that a brighter product is obtained, and
that it is in a finer state of division and therefore more suitable for use in the
manufacture of paint and for the like purposes.
It will be obvious that instead of using a mixture of magnesium sulphate with
the ferrous sulphate, the same object may be attained by mixing with it magnesia,
magnesia carbonate, or similar compounds of magnesia such as magnesite and
magnesium hydrate, and adding sulphuric acid thereto, the object of the process
being to roast the ferrous sulphate in presence of a magnesium compound so as to
obtain as a result a product consisting mainly of ferric oxide and magnesium
sulphate.
The temperature and duration of the operation may be controlled as at present, by
taking samples from time to time.
The sulphuric and sulphurous acids which may be evolved may be conducted to
a vitriol chamber to be utilised in the manufacture of sulphuric acid or, the
sulphuric acid may be condensed and the sulphurous acid gas be led to the vitriol
chamber or be otherwise utilised by known means.
The product of the roasting operation consisting mainly of ferric oxide and
sulphate of magnesium is cooled and lixiviated, by which process the soluble
magnesium salt is separated and the residual red oxide is afterwards dried. The
sulphate of magnesium may be recovered from its solution and be used in the
treatment of further quantities of ferrous sulphate as hereinbefore described.
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 manufacture of red oxide, heating ferrous sulphate in presence of a
suitable magnesium compound and subsequently separating the red oxide by
lixiviation, substantially as and for the purpose hereinbefore described.
2. As a new article of manufacture, a red pigment or paint consisting principally
of red oxide of iron separated by lixiviation from the product obtained by heating
ferrous sulphate in presence of a suitable magnesium compound, substantially as
hereinbefore described.
Dated this 12th day of December A.D. 1893.
WILLIAM E. HEYS,
Agent for the Applicant.