improvement in the manufacture
Year: 1895

page_text: 1, SOPHUS JORGENSEN of Strandvej 14, Copenhagen, in the Kingdom of
Denmark, Manager of Cement-works, do hereby declare the nature of this invention
to be as follows-
My present invention relates to improvements in the manufacture of slag
cements.
The chief objections against slag-cements as hitherto manufactured have been,
partly that they were too slow setting, by which is meant that the time occupied by
the cement in acquiring its initial set or hardening is too long, and partly also that
the surfaces of work made in slag cement have been liable to become soft and
not fit for resisting the wear and tear theroon, though the interior may have kept
its hardness and integrity.
In these two respects the slag cements have always been far behind the true
Portland cements, and thus been unable to come into general use
Now, by my improved way of manufacture I make my slag cement as usual of
finely ground slag and a fine powder of slaked burnt lime, but with an addition by
which I can regulate the setting time of the cement and at the same time materially
improve the hardness, both of the bulk of the work and especially also of the
surface of Buch work, and which in all respects makes my slag cement equal to or
even superior to the best Portland cement.
This addition I make of slag cement by a special mode of treatment and, more-
over, I make it of my own improved slag cement in such manner that a part of my
output is constantly being used in its modified form to make the addition for further
manufacture.
The special treatment of the slag cement which is to form the addition consists
in bringing it to set hard and afterwards subjecting it to a roasting process. To
effect this make the slag cement, which is to form the addition, up with a
sufficient quantity of water to form a paste, which I then spread out in a layer on
n floor to set. As soon as the setting is started I cut this pasto in squares, and
when, after several days, the hardening is fairly progressed I bring these square
blocks into a kiln where they are lightly burnt or roasted. After this process the
blocks are very friable. I then grind them into a fine powder which then is the
anid addition to the slag cement.
In order to show how this addition, which is very quick setting and of great
.

page_text: The mixing of the addition with the slag and hydrate of lime can be done in
several ways by means of drum-and balls or other mixers. I prefer as the cheapest
way to mix and grind the addition together with the two said constituents, and for
this I use tabe-mills which give a very intimate mixing and a very fine grinding,
at the same time having the great advantage of working continuously so that the
materials are fed in and the finished cement leaves the mill uninterruptedly.
Dated this Seventh day of May 1895.
Improvements in the manufacture of Slag Cements.
I, SOPHUS JORGENSEN 14, Strandvej Copenhagen, the Kingdom of
Denmark, Cement Manufacturer, 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 aud by the following statement.-
My present invention relates to improvements in the manufacture of slag
cements.
The chief objections against slag-cements, as hitherto manufactured, have been
partly that they were too slow setting, by which is meant that the time occupied by
the cement in acquiring its initial set or hardening has been too long, and partly
also that the surfaces of work made in slag cement are liable to become soft and
not fit to resist the wear and tear, though the interior may koop its hardness and
solidity. In these two respects the slag-cements have always been far behind the
true Portland-cements and have therefore been unable to come into general use.
Now, by my improved way of manufacturo, I make the slag-cement as usual of
finely ground slag and a fine powder of slaked burut lime, but with an addition by
which can regulate the setting time of the cement and at the same time materially
improve the hardness, both of the bulk of the work made with such cement and
also especially of the surface thereof, and which makes my slag-cement in all
respects equal to or even superior to the best Portland cement.
This addition 1 wake of slag-cement by a special mode of treatment and,
moreover, I make it of my own improved slag-cement, so that a part of every lot
manufactured, is constantly being used in its modified form to make the addition
for the next lot manufactured.

page_text: The special treatment of the slag-cement which is to form the addition consists
in bringing it to set hard, and afterwards subjecting it to a roasting process. To
effect this I make the slag-cement up with a sufficient quantity of water to form a
paste which then spread out in a layer on a floor, to set. As soon as tho setting;
is started I cut this layer in squares and when, after several days, the hardening
has fairly progressed, I bring these square blocka auto a kiln where they are
lightly burnt or 10asted After this process the blocks are very friable. I thon
grind them into a fine powder, which then is the said addition to the slag-cement.
In order to show how this addition, which is very quick-setting and of very
great strength when set, alters and improves the slag-cement, I here give some
actual results arrived at by a trial in an official laboratory for testing cements •
The mixing of the addition into the slag-cement can be done in several ways by
means of drums and balls or other mixers. 1 prefer, as the cheapest way, lo mix
and grind the addition together with the two other materials which form the slag
cement, and for this I use tube mills which give a very intimate mixing and a very
fiue grinding at the same time having the great advantage of working continually
so that the materials are fed in and finished cement leaves the mill uninterruptedly.
Having now described and ascertained my said invention and in what manner
the saine is to be performed, I declare that what I claim 18:
The manufacture of an improved slag-cement consisting of blast furnace slag,-
lydiate of lime and an addition produced of hardened slag cement by roasting,
essentially as described.
'ך שך
J
1000
S. JORGENSEN.