Improvements in the Production of Fireproof Materials and Articles of Enamel.
Year: 1886

page_text: Date of Application, 17th June, 1886.
Complete Left. 24th Feb., 1887
Complete Accepted, 25th Mar., 1887.
PROVISIONAL SPECIFICATION,
Improvements in the Production of Fireproof Materials and
Articles of Enamel.
I, ALEXANDER FELDMANN, chemist, residing at Linden near Hanover, in the
kingdom of Prussia, do hereby declare the nature of this invention to be as
follows:-
My invention consists in the production of fireproof materials and articles, and also
of enamel, out of a composition of one or more of the fluorides of sodium, of calcium,
of magnesium, of strontium, of baryum and of aluminium (whereof the latter five may
contain a fluoride of an alkali-metal) and of one or more of the basic oxides: lime,
magnesia, baryta, strontia, alumina and oxide of zinc.
The substances to be employed are powdered and mixed with water to form a
dough. This dough, whether in crude state or formed into articles of definite shape,
or used as enamel, is dried and burnt at such temperature that its ingredients will
sinter together. By the addition of. some pipe-clay the samic may be rendered more
plastic.

page_text: COMPLETE SPECIFICATION.
Improvements in the Production of Fireproof Materials and
Articles of Enamel.
I, ALEXANDER FELDMANN, chemist, residing at Linden near Hanover, in the
kingdom of Prussia, do hereby declare the nature of this invention and in what
manner the same is to be performed, to he particularly described and ascertained in
and by the following statement:—
My invention consists in the production of fireproof materials and of articles, such as
bricks and vessels, and also of enamel, which are entirely or nearly free from silicic
acid, out of a composition of certain fluoric compounds and the basic oxides: lime,
magnesia, baryta, strontia, alumina and oxyde of zinc. The fluoric compounds to be
used are the fluorides of sodium, of calcium, of magnesium, of strontium, of baryum
and of aluminiumm; but also the double compounds of any of the five last-named
fluorides with a fluoride of an alkali-metal, such as kryolite (Al, F, + 6 Na F) and
chiolite (Al, F +3 Na F) are available.
G
For carrying out the invention the fluoride and the oxide to be employed are first
reduced to a fine powder, which, if insoluble, may be washed if considered necessary.
Alumina may also be used in the gelatinous state in which it is obtained by precipi-
tation from solutions of the same. The substances are then mixed, and so much water
is added thereio that, by kneading, a dough will be produced. This dough being
dried and burnt at such a temperature that its constituents sinter together, forms the
fireproof material. If articles of definite shape are required, these are formed in any
suitable manner, for instance by pressing the dough into molds of wood or metal
which are oiled so as to prevent the dough from adhering to the same. The drying
and burning of the shaped articles is the same as that of the crude dough. In case the
mass is to serve as enamel, it is laid on the metallic surfaces to be coated and heated
together with these. It then adheres firmly to them.
The substances may with advantage he mixed in such proportion that their quantities
by weight correspond to the chemical combining-weights. According to this, 103 parts
by weight of alumina or 56 parts by weight of lime (both substances computed in
anhydrous state) would have to be mixed with 78 parts by weight of fluoride of
calcium (fluor-spar). Under these conditions the ingredients combine in the heat to
form oxy-fluorides. The quantity of the basic oxyde may, however, be considerably
varied. Thus, if the property of the articles, produced from the mixture, to resist
heat, is to be increased, the quantity of the basic oxides requires to be augmented, and
it may amount, in the proportion of the combining-weights, to twice or several times
the quantity of the fluoric compound; whereas if the mixture is to be used as enamel,
or for making vessels, tubes and the like, designed to be exposed to a low heat, a
comparatively smaller quantity of basic oxide may be employed.
The dough obtained as described, and which is not very plastic, may be improved
in this quality by the addition of some pipe-clay. The silica which is thereby brought

page_text: into the mass, as well as any small quantity of silica that may be contained in the
main ingredients employed, combines during the burning process wholly or for the
greater part with a part of the fluorine to form fluoride of silicium, which is
driven off.
Instead of a single fluoride and one of the aforesaid basic oxides, two or more of the
substances of either class may be employed for the mixture in any particular case.
Also ready-formed aluminates of the other said oxides and burnt dolomite may
be used.
The articles manufactured as described, possess, in addition to their quality of being
highly fireproof, the property of resisting chemical influences much better, as well in
hot as in cold state, than other fireproof materials.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, I declare that what I claim is :
1. The process of producing fireproof materials from one or more of the fluorides of
sodium, of calcium, of magnesium, of strontium, of baryum and of aluminium, and one
or more of the basic oxides: lime, magnesia, baryta, strontia, alumina and oxide of
zinc, by comminuting the substances, by mixing them with the addition of water and
forming thereof a dough, and by drying and burning the same, substantially as
hereinbefore described.
2. The process of producing fireproof articles from one or more of the fluorides of
sodium, of calcium, of magnesium, of strontium, of baryum and of aluminium, and
one or more of the basic oxides: lime, magnesia, baryta, strontia, alumina and oxide
of zinc, by comminuting the substances, by mixing them with the addition of water and
forming thereof a dough, by shaping the said dough, and by drying and burning the
articles thus produced, substantially as specified.
3. As an article of manufacture, a fireproof material consisting substantially of a
burnt compound of one or more of the fluorides of sodium, of calcium of magnesium,
of strontium, of baryum and of aluminium, and of one or more of the basic oxides ;
lime, magnesia, baryta, strontia, alumina and oxide of zinc.
Dated the Treante Girst dove at Film 1987