Improvements in the Manufacture of Cement.
Year: 1899

page_text: Date of Application, 31st Aug., 1899-Accepted, 20th Jan., 1900
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Cement.
I, WILHELM SEIDEL, of Amoeneburg, near Bieberich o/Rhine, in the Empire
of Germany, Foreman Miller, 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:-
For reducing and mixing the raw materials, in the manufacture of cement,
three methods are known:
(a) The wet procesa: According to which the raw materials are ground as
fine as possible, in spherical mills, or by means of edge rollers, with the appli-
cation of a large quantity of water. The material is allowed to subside in reser-
voirs, and after drying the slime so obtained, it is further treated in the usual
manner.
(6) The dry process: According to this process the raw materials are dried
thoroughly after being quarried, and reduced by means of edge rollers or in
spherical mills, and then mixed. The dust or meal" so obtained is damped
with sufficient water to render it suitable for moulding, and after being moulded
into bricks it is burnt.
(c) The mixed process; The mixture, first formed in the rough, of a marly
limestone and various argillaceous marls, is first reduced by means of edge rollers
working wet, and then also by means of sets of mill stones working wet, and the
slime is carried into reservoirs, where it subsides. A similar mixture is dried in
slightly altered Bock's channel kilns, and ground dry in sets of horizontal mill
Of the dry "meal
sufficient is added to the wet slime, containing
about 50% of water, to produce a mixture containing 20 to 22 %, which is just
kneadable.
stones.
"
These methods have the following defects:
1. In all three cases, there are drying processes, which are more or less tedious,
and which, apart from the appliances required for the purpose, demand a con-
siderable expenditure of fuel.
2. There is a necessity, (more especially in cases b and c) for extensive reser-
voirs, which serve for the removal of the principal portion of the water from the
fine slime, by means of allowing same to subside. In any case, however, the
slime, so obtained, will, under the most favourable circumstances, still con-
tain at least 50 %, after the water has been run off. In order to admit of its
being manufactured further, it is then absolutely necessary to mix it with a large
quantity of so-called "drying meal"; and to prepare these large quantities of
drying meal," it is then again necessary, for the reasons stated above, to use
a large quantity of fuel for the purpose of drying it, apart from the buildings
and plant required for the purpose.
The process, the subject of the present application for patent, greatly facili-
tates the manufacture of cement slime, as the drying of the raw materials is
reduced to a minimum, and moreover, the quantity of drying meal required is
very small; and finally, because the cement obtained is exceedingly fine,-dust
like and therefore easy of employment.

page_text: According to its principles, this process may be classed amongst the so-called
mixed processes, because in it there is likewise the mixing of a cement slime-
though certainly a very concentrated one-with drying meal," which is then
further manipulated.
The process is executed in the following manner :-
41
By means of spherical mills, the raw material, consisting of marly lime
stones," and various argillaceous marls, is mixed with such a quantity of water
that this admixture of water amounts to about 32 %, the remainder consisting
of the above materials.
These raw materials are filled directly into spherical mills, without being
specially dried, and in the state in which they are extracted from the pits,
etcetera, and the stiff paste, having been sufficiently ground, in the spherical
mills, it is carried on to the sets of mill stones, by means of a suitable separating
apparatus, and with the assistance of elevators. The mill stones may be of the
customary construction, as used for similar purposes in the manufacture of
cement, that is to say, sets of mill stones may be used, of which either the upper
or the lower stone is made movable.
The cement slime having been ground as fine as possible in these sets of mill
stones, it is conveyed to the mixing machine; and if necessary, parts of it are
run into siloes, in order that its composition may be ascertained by means of
exact chemical analysis, and the quantity and description of the drying meal to
be added, fixed accordingly.
In these mixing machines, which are constructed after the manner of the
machines for kneading clay, the finely ground wet paste is mixed with drying
meal, which drying meal, as already explained under paragraph marked c, is
obtained by means of drying the raw materials in kilns, after they have been
-broken up, and reducing them as small as possible to a ("dust-like") powder,
by means of spherical mills or edge rollers.
It is obvious that, by using a slime containing as little water as possible, the
quantity of drying meal which is required only for obtaining a mixture contain-
ing a certain, low percentage of water, will be considerably less than the quan-
tity of drying meal which would have to be added to a very watery cement slime;
and the following figures illustrate this.
According to this invention a cement slime is obtained, of which 100 parts
contain 32 parts of water and 68 parts of cement material. In order now to
obtain, as is requisite, a material containing only 22% of water and 78% of
cement material, it will be necessary to add to the above mixture 46 parts of
drying meal.
If using slime of only 50%, it would be necessary to use 127 parts of drying
meal, and if this ratio is applied to the preceding case, it will be found that the
consumption of drying meal is only about one-fourth of the quantity required in
the second case.
In the manner above described, cement substances are produced in a clay
kneading machine, which contains 22% of water, and which (as they are easily
mouldable) may be formed into bricks in the usual manner, cut, and dried, after
drying in the air, or on an annular kiln (Cohr's system), in order thereupon to
be burnt in the annular kiln.
This process offers the following advantages, as compared with those hitherto
in use.
The raw material may be manufactured directly as it comes from the pit, with-
out first being dried.
The slime reservoirs being unnecessary, the manufacture of the cement may
be carried on throughout the year, and independent of the weather, not being
affected by frost, drought, etcetera.
By the manufacture of the thick paste of cement, the consumption of drying
meal is reduced to such an extent that only small plant is necessary for its pre-
paration; and under certain circumstances, provided the temperature of the

page_text: weather is high, this drying meal may be obtained by drying the quarried
material in the open air.
It has been found that in grinding slime of as thick a consistency as possible,
the slime becomes particularly fine, as all the hard substances contained in the
raw material, such as pebbles, quartz, etcetera, are ground quite small, so that
after the burning in the cement mills a material is obtained in a very fine powder,
which possesses a high degree of applicability.
On account of the absence of the slime reservoirs, a great deal of space is
saved in the installation of the works.
Having now particularly described and ascertained the nature of this inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:-
-
The herein described process for the manufacture of a cement slime of a high
percentage, namely, by the employment of a suitable argillaceous and calcareous
marls mixed without being first dried-in mills, as described, with sufficient
water to produce a percentage of water in the compound as described, and subse-
quently grinding this substance fine between mill stones, and mixed within a
mixing machine with so much dry argillaceous and calcareous marl as will give
the substance so produced a percentage of about 22 % of water; for the purposes
set forth.
одот лев Япо то
WILHELM SEIDEL.
By Cheesbrough & Royston,
Agents for the Applicant, 15, Water Street, Liverpool.