IMPROVEMENTS IN THE MANUFACTURE OF CEMENTS AND COMPOSITIONS FOR VARIOUS PURPOSES
Year: 1881

page_text: PROVISIONAL SPECIFICATION left by Alexander Melville Clark at tho
Office of the Commissioners of Patents on the 18th June 1881. A communi-
cation from abroad by Emile Eugene Albert Sorel de la Société Générale
des Agglomérés Magnesiens, of Paris, France.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of
Middlesex, Patent Agent. "IMPROVEMENTS IN THE MANUFACTURE OF CEMENTS
AND COMPOSITIONS FOR VARIOUS PURPOSES." [A cominunication from abroad by
Emile Eugene Albert Sorel de la Société Générale des Agglomérés Magnesiens, of
Paris, France.]
This Invention relates to an improved kind of cement, and to compositions
thereof with other materials for various purposes.
Magnesia and sulphate of magnosia combined with water produce a cement which
rapidly acquires extreme hardness. This new cement may be prepared in two
ways, 1st, by mixing magnesia with crystallized sulphate of magnesia and wetting
with water, or 2nd, by first dissolving the sulphate of magnesia in water and
wetting the magnesia with this solution. As this new cement sets rapidly in hot
weather, it is better to proceed in the way first mentioned for the following reason:-
When the sulphate of magnesia is dissolved, a very considerable degree of cold is
produced in the liquid, and if therefore the sulphato be dissolved when the
cement is made, the mass will be cooled, and the setting of the cement will be
retarded.
The proportions of the ingredients of the cement may be considerably varied. A
cement composed as follows will acquire in 24 to 48 hours (according to the
temperature) the hardness of marble :-

page_text: per square centimetre, and double this amount after 8 days. This remarkable
property renders the cement eminently suited for the manufacture of a great
number of products of which the following are a few examples :-
The composition produces an artificial building stone closely resembling natural
freestone in all its different varieties of hardness.
property renders the cement eminently suited for the manufacture or
number of products of which the following are a few examples :-
a great
The composition produces an artificial building stone closely resembling natural
freestone in all its different varieties of hardness.
Magnesia -
Powdered limestone
Solution of sulphate of magnesia }- -{\
at 25° or 30° B.
-
100 parts.
-
400 to 1000 parts.
Sufficient to make a
thick mortar.
For low priced products the following composition is employed:
Magnesia -
Sand or limestone
4 Gravel or similar materials
Sulphate of magnesia at 25° or 30° B.
100 parts.
200 to 600 parts.
400 to 1600 parts.
Sufficient to make
a thick mortar.
This composition is suitable for making reservoirs, basins, blocks, bricks, and for
hydraulic work generally.
It should be here observed that in the case of products intended to remain under
water, it is desirable to include silicious materials in the composition. By mixing
with this cement sandstone, flint, emery, or other hard substances, mills may be
made suitable for grinding, sharpening, working inetals, and also for glassworkers'
and optical purposes.
By adding to formula No. 1 100 or 200 parts of powdered white marble and
coloring matters in powder, imitations of the various marbles may be produced.
In short, many kinds of substances may be agglomerated with the cement for
various purposes.
A great advantage of this new comment is that it neither expands nor shrinks,
and is consequently not liable either to crack or warp, as the water it contains does
not evaporate.
This cement may also be combined with known cements for various purposes.
Should pure or nearly pure magnesia not be readily obtainable, calcined dolomites
or magnesites may be employed.
I will now proceed to describe some modifications and improvements which may
be made in this new cement.
1st Modification. (Magnesia A.)-This consists in burning together the magnesia
and sulphate of magnesia in the following way :-Hydrated magnesia is mixed with
a more or less concentrated solution of sulphate of magnesia, and when the mixture
has become sufficiently stiff, it is moulded into lumps or bricks, and calcined at
about the temperature of a lime kiln. The product obtained when pulverised and
gauged either with water or with a dilute solution of sulphate of magnesia, sets
under water and becomes much harder than the samé cement if prepared with
ordinary magnesia.
For the sake of clearness I will hereinafter designate the cement just described
Magnesia A."
In this cement (Magnesia A) a larger or smaller proportion of sulphate of
magnesia may be used, but good cements have been made with the following
composition :-
°
Hydrated magnesia (25% of water)
Sulphate of magnesia at 30°
100 parts.
75 "
It is important to use hydrated magnesia, as sulphate of magnesia would
combine with anhydrous magnesia, and the result of the calcination would not bo
so good.
2nd Modification. (Magnesia B.)-The qualities of the coment in question aro
also auginented by the addition of silica, alumina, and protoxide of iron, together

page_text: or separately. In practice this addition is made by mixing clay or combinations
of various clays or ochres with the magnesia, and forming the mixture into bricks
and calcining as above described.
Good results have been obtained with magnesia giving on analysis after calcination
the following result:-
product:-
Magnesia A or C-
100.
Common limestone pulverized, from 400 to 600.
Sulphate of magnesia at 20°
Chloride of magnesium at 30°
80.
40.
By using more or less limestone the cost will be greater or less. The limestone
may be replaced by other cheap substances, and a little coloring matter may be
added to produce a colored cement or plaster.