An Artificial Stone Composition.
Year: 1892

page_text: Date of Application, 9th Aug., 1892-Accepted, 8th Apr., 1893,
An Artificial Stone Composition.
We, JOSEPH EVERHARD KESELING, and CHARLES FUCHS, Junior, both of
5 Bowling Green, New York City, State of New York, United States of America,
Chemists 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 artificial stone compositions and the object of the
invention is to provide a composition of comparatively cheap materials, easily
prepared, and then converted into stone, of great density and durability. More
particularly is it an object to provide an artificial stone that will withstand sudden
and extreme changes of temperature.
Many artificial stones have been used for ornamental work, which if exposed to
the humidity of the atmosphere, absorb moisture and then disintegrate. The
composition hereinafter described may after it becomes set, be immersed in boiling
water for hours, and then plunged into ice cold water without affecting it in any
manner.
To attain these objects we take a certain quantity of oxide of magnesium and
chloride of magnesium and stir together until the resultant cement forms a plastic
paste. The oxide of magnesium or calcined magnesia, we obtain by burning pure
magnesite in kilns, or preferably in iron or clay retorts, at such a temperature and
length of time as will expel all carbonic acid from the crude material. Magnesia
The calcined
containing a noticeable quantity of lime should not be used.
magnesia thus obtained is then ground to an impalpable powder.
To obtain chloride of magnesium containing no sulphuric acid salts and free
acids we take hydrochloric acid of 1.16 spec. g. and gradually add such an amount
of calcined magnesia that the resulting chloride of magnesium will be perfectly
neutral, as indicated by a litmus paper test; it is then a yellow oily liquid
34° Beaume and can be stored in iron drums.
This it will be noted is very different from the magnesium chloride salt of
commerce which is generally dissolved in water for the production of a cement.
The commercial, magnesium chloride salt contains sulphuric acid salts and free
acids which as is well known do not resist the influence of the elements, and as
they also absorb carbonic acid from the air such salts render the produced stone
material liable to cracks and final disintegration.
To obtain a perfectly basic cement we add the neutral magnesium chloride
obtained as above described to a certain quantity of calcined magnesia and stir the
mixture until the cement is plastic. The general proportions of the several
ingredients are as follows:-30 lbs. magnesium oxide; 20 lbs. magnesium chloride;
70 lbs. dry sharp sand and 2 lbs. asphaltum dissolved in oil of turpentine.
Instead of sand, ground slate, sandstone or flint powder may be used as the.
filling material according to the application desired. The heat generated by the
crystallizing process of the oxychloride drives off the asphaltum solvent and leaves
the stone perfectly and uniformly impregnated with the asphaltum. The amount
of asphaltum used will be a minimum in tiles, slabs, &c., and will reach the
maximum in such articles as are subjected to extreme changes of temperature such
as wash-tubs and bath tubs. The asphaltum in combination with the sand filling
material renders the whole mass so tenacious and heat conducting that it will
permit a considerable expansion and contraction without affecting the integrity of
the material. The mixture being semi-liquid can be readily poured into moulds
of any shape. It may also be obtained sufficiently thin to flow from a brush and

page_text: thus form a paint or it may be made stiff enough for troweling such as plaster
work suitable mineral colors may also be introduced.
The elimination of the chloride of magnesium takes place gradually and
imperceptibly when exposed to the atmosphere, and we eventually obtain a basic
stone consisting of pure magnesium hydrate, sand and asphaltum.
Stones such as tiles, &c., are dried in a room of ordinary temperature. It is
sometimes expedient for articles exposed to the atmosphere to have the magnesium
chloride eliminated rapidly. This we do by taking the stone after it is set and
well dried out and subject it to a hot water bath, by immersion, and then dry it
again. Articles made under pressure, such as standard size bricks, we subject to
a steam bath under 8 to 10 atmospheric pressures. This very quickly eliminates
the chloride and the bricks are dried again in the ordinary temperature.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. A composition of matter for the manufacture of artificial stone which consists
of a basic cement of oxide of magnesium and neutral chloride of magnesium,
asphaltum and sand or analogous material.
2. The process of manufacturing artificial stone which consists in first obtaining
a basic cement of oxide and neutral chloride of magnesium, then adding sand and
asphaltum, then drying the resultant stone, and then immersing such stone in hot
water to drive off the chloride.
Dated this 4th day of August 1900
H. D. FITZPATRICK,
70, Wellington Street, Glasgow, Agent.