Improved Method of Manufacturing Hydraulic Cement.
Year: 1894

page_text: Date of Application, 9th Jan., 1894-Accepted, 10th Mar., 1894
COMPLETE SPECIFICATION.
Improved Method of Manufacturing Hydraulic Cement.
I, GUSTAV WILHELM ALBRECHT STEIN, of Wetzlar in the Empire of
Germany, Manufacturer, do hereby declare the nature of this invention and
in what manner the same is to be performed, to be particularly described aud
ascertained in and by the following statement:-
According to the known method of manufacturing artificial Portland-cement,
calcareous and argilliferous materials are thoroughly incorporated, burnt until
sintered & then reduced to powder. In thus burning such materials, it is a known
fact that a more or less hard and compact mass is formed, whose preliminary
disintegration requires considerable mechanical power and powerful machines,
i.e. stone-breaking machines, disintegrators, etc.
The object of my invention is to simplify the method of manufacturing Portland
cement in such manner, that the sintered cement-mass or clinker, when exposed to
air, becomes tender or brittle and breaks or crumbles into small pieces which
can be immediately fed into the reducing or grinding apparatus, without being
subjected to a tedious and expensive preliminary disintegration.
I attain such result by adding to the raw materials or admixture of raw materials
previously prepared for burning, a certain amount of blast-furnace slag or slag-
sand, the quantity being regulated according to the nature and proportions of the
raw materials--from 5 to 30 parts of slag sand to 100 parts of raw materials. If
such an admixture containing a small quantity of the slag-sand in suitable and
proper distribution is now burnt, the same becomes completely sintered, but, by
reason of the added slag-sand, disintegrates and falls or crumbles into small pieces
during cooling, or becomes so brittle, that a slight blow for instance with a
hammer-preferably when being taken from the kiln,-effects such a disin-
tegration, that the burnt mass can be fed directly to the apparatus for crushing or
reduction to a fine powder.
According to my invention, the method can also be carried out by adding larger
quantities of granulated, unground blast furnace slag or slag-sand in the proportion
of 30 to 125 parts of slag-sand to 100 parts of raw materials-the raw materials
being previously reduced to a powder-or by adding a composition of raw
materials, yielding the known hydraulic cement, and then subjecting same to the
burning process. A granular, brittle product is therefore obtained according to
the composition of the raw materials or the admixture, and the degree of heat
to which it has been subjected, the properties of such product, after reduction to
a powder, more or less approaching or resembling those of Portland-cement,
Roman-cement or hydraulic limes.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what. 1
claim is :-
1. Improved method of manufacturing hydraulic cement, rendering unnecessary
the preliminary disintegration of the burnt materials for grinding or reducing to
powder, & consisting therein, that granulated, unground blast furnace slag-
so-called slag-sand, in the proportion of 5 to 30 parts of slag-sand, to 100 parts of
raw materials, is added to the raw materials or the composition of raw materials
previously prepared for burning, & such composition burnt until sintered, sub-
stantially as described.
2. The employment of the method of manufacturing cement as described in
Claim 1, in connection with raw materials yielding other hydraulic cements, in

page_text: such manner that the raw materials are reduced to a powder before the slag-sand,
in the proportion of 30 to 125 parts of slag-sand to 100 parts of raw materials, with
which they are burnt, is added substantially as described.
Dated this 8th day of January 1894.
MARKS & CLERK,
18, Southampton Buildings, London, W.C., Agents.