AN IMPROVED PROCESS FOR MANUFACTURING MAGNESIAN FIRE BRICKS
Year: 1880

page_text: LETTERS PATENT to Thomas Morgan (Secretary of the Inventors' Patentright
Association, Limited), 21, Cockspur Street, Charing Cross, Westminster, in the
County of Middlesex, for an Invention of "AN IMPROVED PROCESS FOR
MANUFACTURING MAGNESIAN FIRE BRICKS." A communication from abroad
by Baron Gustave d'Adelswärd, of Paris, in the Republic of France.
PROVISIONAL SPECIFICATION left by the said Thomas Morgan at the
Office of the Commissioners of Patents on the 2nd January 1880.
THOMAS MORGAN (Secretary of the Inventors' Patentright Association, Limited),
21, Cockspur Street, Charing Cross, Westminster, in the County of Middlesex.
"AN IMPROVED PROCESS FOR MANUFACTURING MAGNESIAN FIRE BRICKS." A
communication from abroad by Baron Gustave d'Adelswärd, of Paris, in the
Republic of France.
Magnesia has already been employed in the composition of fire bricks capable of
resisting very elevated temperatures; but it has heretofore been found difficult to
obtain a supply of magnesia of sufficient purity and in particular sufficiently free
of silica for this purpose. Now by means of this Invention this difficulty is sur-
mounted as hereinafter described. The novel and distinguishing feature of this
Invention consists of the preparation of hydrated magnesia by precipitating the
magnesia in natural or artificial solution of salts of magnesia by pure lime, which
is added in equivalent quantity, it being strictly necessary to adhere to this
proportion. The artificial solutions of salts of magnesia may be readily prepared
by submitting magnesia rocks, such as dolomite, for example, to the action of
hydrochloric acid, or of the residues of the manufacture of chlorine. This process
when compared with the employment of dolomite as a precipitant in the place of
lime presents the following advantages, namely:-1st, it enables the magnesia to be
obtained with a minimum of silica; and, 2ndly, common dolomite, which is of a too
silicious or argillaceous nature to be employed in the more direct manner, is enabled
to be used in the manufacture of products capable of resisting an extreme degree of
heat. The pure hydrated magnesia having been obtained by chemical precipitation
in the manner described, with a proper quantity of lime of the greatest possible
purity is dried and calcined.. After being pulverised it is moistened with a small

page_text: proportion of water in such a manner as to obtain a very stiff paste, after which it
is placed in a mould and formed into bricks of the required shape by submitting
it to a very high pressure.
When the bricks have been dried they are baked by exposure during at least
twelve hours to a very elevated temperature. The magnesian bricks so obtained
are principally intended for metallurgical and ceramic purposes, for lining or
protecting furnaces at the parts which are exposed to intense heat. These bricks
are capable of resisting elevated temperatures without deterioration by reason of
the purity of the materials of which they are composed, a result which has not
been previously attained.. In the above described Invention the following are
considered important points or features:-The preparation of magnesia in a pure
condition by precipitating it with pure lime from natural or artificial solutions of
salts of magnesia, the same constituting the distinguishing feature of the process
described for the manufacture of fire bricks of magnesia.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
said Thomas Morgan in the Great Seal Patent Office on the 17th June
1880.
THOMAS MORGAN (Secretary of the Inventors' Patentright Association, Limited),
21, Cockspur Street, Charing Cross, Westminster, in the County of Middlesex.
"AN IMPROVED PROCESS FOR MANUFACTURING MAGNESIAN FIRE BRICKS." (A
communication from abroad by Baron Gustave d'Adelswärd, of Paris, in the
Republic of France).
Magnesia has already been employed in the composition of fire bricks capable of
resisting very elevated temperatures, but it has heretofore been found difficult to
obtain a supply of magnesia of sufficient purity, and in particular sufficiently free
from silica for this purpose.
Now by means of this Invention this difficulty is surmounted as hereinafter
described.
The novel and distinguishing feature of this Invention consists in the preparation
of hydrated magnesia by precipitating the magnesia in natural or artificial solutions
of salts of magnesia by pure lime, which is added in equivalent quantity, it being
strictly necessary to adhere to this proportion. The artificial solutions of salts of
magnesia may be readily prepared by submitting magnesian rocks such as dolomite,
for example, to the action of hydrochloric acid, or of the residues of the manufacture
of chlorine. This will be readily understood by the practical man.
This process,
when compared with the employment of dolomite as a precipitant in the place of
lime, presents the following advantages :-
1st, it enables the magnesia to be obtained with a minimum of silica; and, 2nd,
common dolomite, which is of a too silicious or argillaceous nature to be employed
in a more direct manner, is enabled to be used in the manufacture of products
capable of resisting an extreme degree of heat. The pure hydrated magnesia
having been obtained by chemical precipitation in the manner described (with a
proper quantity of lime of the greatest possible purity) is dried and calcined.
After being pulverized it is moistened with a small proportion of water in such a
manner as to obtain a very stiff paste, after which it is placed in a mould and
formed into bricks of the required shape by submitting it to a very high pressure.
When the bricks have been dried they are baked by exposure during at least
twelve hours to a very elevated temperature. The magnesian bricks so obtained
are principally intended for metallurgical and ceramic purposes, for lining or pro-
tecting furnaces at the parts which are exposed to intense heat.
These bricks are capable of resisting elevated temperatures without deterioration
by reason of the purity of the materials of which they are composed, a result which
has not been previously obtained.
Having now particularly described and ascertained the nature of the said Inven-
tion, and in what manner the same is to be performed, I hereby declare that I claim
as peculiar in the process described for preparation of magnesian fire bricks the
preparation of magnesia in a pure condition by precipitating it with pure lime from
natural or artificial solutions of salts of magnesia.
In witness whereof, I, the said Thomas Morgan, have hereunto set my
hand and seal, this Sixteenth day of June, in the year of our Lord
One thousand eight hundred and eighty.