Improvements in the Manufacture of Cement.
Year: 1893

page_text: Date of Application, 7th Apr., 1893
Complete Specification Left, 8th Jan., 1894-Accepted, 7th Apr., 1894
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Cement.
1, GUSTAVE GIN of 15 Rue des Halles, Paris, France, Engineer, do hereby
declare the nature of this invention to be as follows:-
This invention has reference to improvements in the manufacture of cement, the
object being to manufacture a new cement, having all the valuable qualities or
known cements, but at a considerably less cost.
For this purpose carboniferous schists shales or slate substances which constitute
a waste material in coal-mining are employed in the manufacture of cement
according to this invention. These schists have compositions which are more or
less variable but in which silicate of alumina, associated with a small proportion of
various silico-aluminates such as that of potash, of soda, oxide of iron &c.,
predominates. Amongst other things they contain a quantity, often considerable
of bituminous matters and of carbon the origin of which is connected with the
formation of the coal enclosed between the schist beds. By treating these clay
schists in-the manner hereinafter described and by mixing them with a suitable
quantity of limestone a cement is obtained the composition and qualities of which
are analogous to those of the best cements heretofore made and to which can
easily be imparted the property of hardening either slowly or quickly as may be
required.
The method of manufacturing my cement is somewhat similar to that employed
for the preparation of the cements now in common use and comprises:
The preparation of the raw materials; the measurement, the mixing, the wetting
and the agglomeration of such material; and the baking, pulverizing, sifting and
bagging thereof.
In the preparation of the raw materials the schists and the limestone should be
first of all as intimately mixed as possible; for that purpose they should be
previously reduced to a very fine powder. As regards the limestone, before being
introduced into the mass, it can be reduced to powder, either in the form of lime
pulverized by slacking and sifting; or in the form of carbonate of lime, previously
dried at a moderate temperature, pulverized by means of disintegrating machines,
then ground by mill-stoues and sifted for example, with a No. 60 sieve.
The constituent argillaceous and calcareous materials being reduced to powder
are intimately mixed together the proportions being regulated in such a manner that
after the baking operation the principal constituents are within the following
limits
The delivery of the schist and limestone into the mixing vessel is regulated in
such a manner that these substances are in suitable proportions to be mixed into a
sufficiently homogeneous state.
From the dry mixer the material passes into the wet mixer, in which a
pulverizing injector gives to it that degree of humidity which is absolutely necessary
in order that the mass may be easily agglomerated and compressed into briquettes.
The mixture from the wet mixer is delivered to a briquette machine. The
briquettes which on leaving the moulds are received on trucks or carriages are
conducted to the drying or to the baking oven according to the degree of moisture
in the briquettes.

page_text: The briquettes can be baked in ordinary ovens, but it is preferable to bake them
in continuous ovens with compartments. The baking of the cement can be effected
with a quantity of combustible material less than that generally employed for
ordinary cements. In fact these schists contain a certain proportion of carbon
disseminated through the briquettes and there may result from this fact, in certain
cases considerable economy in the baking of the briquettes.
Moreover; the presence, in these schists of easily fusible alkaline silico-
aluminates permits the briquettes at a comparatively slightly elevated temperature
to assume a semi-vitreous state which allows the chemical precipitation of silica
and of lime.
The process indicated is practically the same for refractory coal schists, in which
case the economy of combustible material mentioned is not obtained.
The products of the baking operation having undergone a partial vitrification are
carried to the disintegrators, then to the millstones, and are finally sifted with a
No. 80 sieve.
The advantages resulting from my invention will be readily understood. It is
well known that coal companies are embarrassed with the enormous masses of schist
which they are obliged to bring to the surface and which excepting those of the
coal beds of Wales, or of the basin of Charleroi, which are applied to refractory
products or revetments, have prior to my invention been valueless. From the fact
that for baking 1000 kilogs. of cement about 300 kilogs. of coal are necessary, it is
obvious that it is of great advantage to find at the places of production both the
raw material and the combustible material necessary for its transformation into an
industrial product. To this advantage is added the economy which results from
the presence in those schists which are not refractory, of a considerable quantity of
carbon either-forming an integral part of the mass, or simply interposed between
the lamina of the schist. I thus utilize a quantity of combustible matter which
has heretofore been a waste material and has constituted an encumbrance and
a loss by rendering useless the land used for its reception.
Dated this 6th day of March 1893.
.
GUSTAVE gin,
By L. W., per F. B.
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Cement.
I, GUSTAVE GIN, of 15 Rue des Halles, Paris, France, Engineer, 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:-
This invention has reference to improvements in the manufacture of cement, the
object being to manufacture a new cement having all the valuable qualities of
known cements, but at a considerably less cost.
For this purpose, carboniferous schists, shales or slaty substances (hereinafter
referred to as schists), which constitute a waste material in coal-mining, are
employed in the manufacture of cement according to this invention. These schists
have compositions which are more or less variable but in which silicate of alumina,
associated with a small proportion of various silico-aluminates such as that of
potash, of soda, and of oxide of iron predominates. Amongst other things, they
contain a quantity, often a considerable quantity, of bituminous matters and of
carbon, the origin of which is connected with the formation of the coal enclosed
between the schist beds. By treating these clay schists in the manner hereinafter
described, and by mixing them with a suitable quantity of limestone, a cement is
obtained the composition and qualities of which are analogous to those of the best

page_text: cements heretofore made and to which can easily be imparted the property of
hardening either slowly or quickly as may be required.
The method of manufacturing my cement is somewhat similar to that employed
for the preparation of the cements now in common use and comprises :-
The preparation of the raw materials; the measurement, the mixing, the
wetting and the agglomeration of such material; and the baking, pulverizing,
sifting and bagging thereof.
In the preparation of the raw materials the schists and the limestone
should be first of all as intimately mixed as possible.
For this purpose
they should be previously reduced to a very fine powder. As regards the
limestone, before being introduced into the mass, it can be reduced to powder,
either in the form of lime pulverized by slacking and sifting; or in the form of
carbonate of lime, previously dried at a moderate temperature, pulverized by
means of disintegrating machines, then ground by mill-stones, and sifted for
example, with a No. 60 sieve.
The constituent argillaceous and calcareous materials being reduced to powder,
are intimately mixed together and their composition being known, the proportions
thereof used are regulated in such a manner that the ratio existing between the
constituents CaO + MgO and SiO, + Al₂O, shall after the baking operation be
not greater than three of the former to one of the latter, or if Fe,O, be present
in sufficient quantity to affect the result that the ratio between the CaO + MgO
and SiO, + Al₂O3 + Fe,Os shall be not less than three of the former to one of
the latter as indicated by the following formulæ :—
100
By the treatment of 34 parts of this schist with 66 parts of the limestone a
cement would be theoretically produced in which the ratio between the
MgO+CaO and Al,O, + SiO2 + Fe,O, would be as 36-2 to 63-8 or (neglecting
the small quantity of Fe,O,) as 32.9 to 63:8. The proportions-of-raw-materials
required for the manufacture of the cement vary according to the quantity of foreign
substances present.
The schist above referred to was found to contain in the raw state 30% of
carbonaceous matter, and water of combination and 10% of moisture; the lime
stone containing 20% of quarry moisture. To produce 100 parts of cement from
such a schist 200 parts of raw material will be required in the proportion of
56 parts of schist to 144 parts of limestone.
The delivery of the schist and limestone into the mixing vessel is regulated in
such a manner that these substances are in suitable proportions to be mixed into a
sufficiently homogeneous state.
From the dry mixer the material passes into the wet mixer in which a
pulverizing injector gives to it that degree of humidity necessary to enable the
mass to be easily agglomerated and compressed into briquettes.
The mixture from the wet mixer is delivered to a briquette machine. The
briquettes which on leaving the moulds are received on trucks or carriages are

page_text: conducted to the drying, or to the baking oven, according to the degree of moisture
in the briquettes.
The briquettes can be baked in ordinary ovens, but it is preferable to bake them
in continuous ovens with compartments. The baking of the cement can be
effected by the combustion of a quantity of combustible material less than that
generally employed for ordinary cements, owing to the fact that the schists
employed contain a certain proportion of carbonaceous matter which is dis-
seminated through the briquettes. In consequence of this, in certain cases
considerable economy in the baking of the briquettes is effected. Moreover, the
presence in these schists of easily fusible alkaline silico-aluminates, permits the
briquettes, at a comparatively slightly elevated temperature, to assume a semi-
vitreous state which allows of the chemical precipitation of silica and of lime.
The process indicated, is practically the same when employing refractory coal
schists, in which case the economy of combustible material mentioned, is not
obtained.
The products of the baking operation having undergone a partial vitrification,
are carried to the disintegrators, then to the millstones, and are finally sifted with
a No. 80 sieve.
The advantages resulting from my invention will be readily understood. It is
well known that coal companies are embarrassed with the enormous masses of
schist which they are obliged to bring to the surface, and which, excepting those
of the coal beds of Wales, or of the basin of Charleroi, which are applied to
refractory products or revetments, have prior to my invention been valueless.
From the fact that for baking 1000 kilogs. of cement about 300 kilogs. of coal are
necessary, it is obvious that it is of great advantage to find at the places of
production both the raw material and the combustible material necessary for its
transformation into an industrial product. To this advantage is added the economy
which results from the presence in those schists which are not refractory, of a
considerable quantity of carbon, either forming an integral part of the mass, or
simply interposed between the lamina of the schist. In these cases I thus utilize
a quantity of combustible matter which has heretofore been a waste material and
bas constituted an encumbrance and a loss by rendering useless the land used for
its reception.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what I
claim is :-
1. The manufacture in the manner hereinabove described of cement, using
carbonaceous schists, shales or slaty substances and limestone as set forth.
2. Utilizing schists, shales or slaty substances of the kind herein referred to in
the manufacture or production of cement as set forth.
Dated this 8th day of January 1894.