An Improvement in the Manufacture of Cement.
Year: 1898

page_text: Date of Application, 29th Aug., 1898
Complate Crecification loft 20th May 1809_Accepted 28th Oct. 1899
An Improvement in the Manufacture of Cement.
I, JACOB STEIGER, of 24, Finsbury Square, in the City of London, Manu-
facturer, do hereby declare the nature of my said invention to be as follows:-
This invention relates to the manufacture of a cement in a dry pulverulent
form which can be used in admixture with water and any suitable materials for
the manufacture of artificial stone, artificial fuel blocks and many other articles,
the cement serving to give coherence to the materials.
For this purpose I take a solution of chloride of magnesium and of silicate of
potash or of silicate of soda mix same thoroughly, and after the chemical change
has taken place I reduce the mass by evaporation to a dry substance.
After cooling, the mass is ground to a fine powder; I also prepare in form of
fine powder magnesia, such as that obtained by calcining magnesite; I thoroughly
mix the powdered magnesia, the powdered combined chloride of mag-
nesium and silicate of potash or of silicate of soda prepared as above described,
the mixture constituting a cement in form of a dry powder which can be used
with water to cement any suitable materials together.
The main feature of the invention is the production of a mixture of dry
chloride of magnesium and silicate of potash or silicate of soda by means of
evaporation of the two solutions, which, in being mixed and exposed to heating,
are subjected to chemical changes. The quantities of the two solutions must
be determined in such a manner that a small part of the chloride of magnesium
remains unchanged as surplus quantity, while the other part (about a half to
two-thirds part) is transformed into hydro-silicate of magnesium and chloride
of alkali.
Whilst the reduction of pure chloride of magnesium to a powder can be accom-
plished with great difficulties only, and hardly without chemical changes, this
process can easily be accomplished with above described mixture.
This is due partly to the presence of hydrosilicate of magnesium, partly to the
influence of the chloride of alkali, which latter forms with the chloride of mag-
nesium a permanent double salt.
This dry mixture has also the advantage that the chloride of magnesium as
well as the silicate of magnesium retain their cementing qualities and act com-
bined upon the calcined magnesia owing to their unchanged hydratic qualities.
Experience has shown that cement produced in the foregoing manner has been
exposed to the air without showing signs of deliquescence and after mixture with
water has shown remarkable strength and hardness. At the same time the ten-
dency of chloride of magnesium of attracting moisture in the air is eliminated so
that there can be no later sweating of the manufactured and hardened cement.
This is due partly to a reduced amount of free chloride of magnesium owing to
the combination of the latter with the silicate, but especially to the formation of
a double salt by the surplus chloride of magnesium, with the chloride of alkali,
produced by the chemical action of the chloride of magnesium on the silicate,
which chloride of alkali, even exceeds the chloride of magnesium in its cement-
ing property. Of further favourable effect is the magnesium silicate produced in
the same manner and reduced to a powder, because the silicate contained therein

page_text: Tests
is in such favourable easily soluble hydrated condition that its hardening and
cementing influence (which is simultaneous with the action of the chloride of
magnesium) upon the calcined magnesia, becomes a prominent feature.
have shown that only such mixtures of chloride of magnesium and silicate which
have been produced in the above described manner have had a beneficial effect
upon the hardness of the objects produced therewith, whilst the application of the
two substances in liquid form or in powdered form but dried separately and sub-
sequently mixed, did not exercise the same favourable influence.
This invention distinguishes itself therefore from processes hitherto known
where silicates have been used, by a mixture of chloride of magnesium and of
silicate of potash or soda, subsequent reduction to powder of the mass by means
of evaporation and the production of a dry mixture of chloride of magnesium,
chloride of alkali, and silicate of magnesium which can be transformed into a
durable dry and highly efficient cement by the addition of calcined magnesium.
Dated 29th August 1898.
I, JACOB STEIGER, of 24, Finsbury Square, in the City of London, Manu-
facturer, do hereby declare the nature of my said invention and in what manner
the same is to be performed, to be particularly described and ascertained in and
by the following statement:-
This invention relates to the manufacture of a cement in a dry pulverulent
form which can be used in admixture with water and any suitable materials for
the manufacture of artificial stone; artificial fuel blocks or briquettes and
many other articles, the cement serving to give coherence to the materials.
For this purpose I take a solution of chloride of magnesium and of silicate of
potash, or of silicate of soda; mix same thoroughly and after the chemical change
has taken place I reduce the mass by evaporation to a dry substance.
After cooling, the mass is ground to a fine powder; I also prepare in form of
fine powder magnesia, such as that obtained by calcining magnesite, I thoroughly
mix the powdered magnesia, the powdered combined chloride of magnesium and
silicate of potash or of silicate of soda prepared as above described, the mixture
constituting a cement in form of a dry powder which can be used with water to
cement any suitable materials together.
The proportions of the ingredients are as follows:-
Chloride of Magnesium (dry)
Silicate of soda (or potash)
Magnesia
20% to 25%
12% to 15
60 % to 65 %
The main feature of the invention is the production of a mixture of dry chloride
of magnesium and silicate of potash or silicate of soda by means of evaporation
of the two solutions, which in being mixed and exposed to heating, are sub-
jected to chemical changes. The quantities of the two solutions must be deter-
mined in such a manner that a small part of the chloride of magnesium remains
unchanged as surplus quantity, while the other part, (about a half to two thirds
part) is transformed into hydrosilicate of magnesium and chloride of alkali.
Whilst the reduction of pure chloride of magnesium to a powder can be accom-
plished with great difficulties only, and hardly without chemical changes, this
process can easily be accomplished with above described mixture.

page_text: This is due partly to the presence of hydro-silicate of magnesium, partly to the
influence of the chloride of alkali, which latter forms with the chloride of mag-
nesium a permanent double salt.
This dry mixture has also the advantage that the chloride of magnesium as
well as the silicate of magnesium retain their cementing qualities and act com-
bined upon the calcined magnesia owing to their unchanged hydratic qualities.
Experience has shown that cement produced in the foregoing manner has been
exposed to the air without showing signs of deliquescence and after mixture with
water has shown remarkable strength and hardness.
At the same time the tendency of chloride of magnesium of attracting moisture
in the air is eliminated so that there can be no later sweating of the manufactured
and hardened cement.
"
This is due partly to a reduced amount of free chloride of magnesium owing to
the combination of the latter with the silicate, but especially to the formation
of a double salt by the surplus chloride of magnesium with the chloride of alkali,
produced by the chemical action of the chloride of magnesium on the silicate,
which chloride of alkali even exceeds the chloride of magnesium in its cementing
property. Of further favourable effect is the magnesium silicate produced in the
same manner and reduced to a powder, because the silicate contained therein is
in such favourable, easily soluble, hydrated condition that its hardening and
cementing influence (which is simultaneous with the action of the chloride of
magnesium) upon the calcined magnesia, becomes a prominent feature.
Tests have shown that only such mixtures of chloride of magnesium and sili-
cate which have been produced in the above described manner have had a bene-
ficial effect upon the hardness of the objects produced therewith, whilst the
application of the two substances in liquid form or in powdered form but dried
separately and subsequently mixed, did not exercise the same favourable influence.
This invention distinguishes itself therefore from processes hitherto known
where silicates have been used, by a mixture of chloride of magnesium and of
silicate of potash or soda, subsequent reduction to powder of the mass by means
of evaporation and the production of a dry mixture of chloride of magnesium,
chloride of alkali, and silicate of magnesium which can be transformed into a
durable dry and highly efficient cement by the addition of calcined magnesium.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is: :-
1. Process for the manufacture of a silicated magnesia cement in dry form,
the special feature of which is constituted by the mixing of solutions of chloride
of magnesium and silicate of potash, or soda, the reduction of the mass, thus
mixed, to a dry powder by heating and the addition of calcined magnesia with or
without filling material, substantially as set forth.
2. Process for the manufacture of a silicated magnesia cement in dry form,
consisting of mixing a solution of chloride of magnesium with a solution of sili-
cate of soda or potash in suitable proportions whereby hydro-silicate of magne-
sium and chloride of alkali are formed and leaving a small part of unchanged
chloride of magnesium; evaporating, drying and powdering the mixture; and
adding thereto a suitable proportion of powdered calcined magnesium or mag-
nesia, substantially as set forth.
D
1 001
GEORGE DOWNING & SONS,
8, Quality Court, London, W.C., Agents for the Applicants.