An Improved Process for the Manufacture of Cement and Cement-mortar.
Year: 1895

page_text: Date of Application, 28th Dec., 1895-Accepted, 1st Feb., 1896
COMPLETE SPECIFICATION.
An Improved Process for the Manufacture of Cement and
Cement-mortar.
I, MARTIN NAHNSEN, of Schönebeck on the Elbe, Kingdom of Prussia, German
Empire, 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 :-
On manufacturing sulphate of alumina from bauxite, clay, kaolin, alumite,
and similar minerals, there result large quantities of residues that are insoluble in
water. Said residues have up to now not found a satisfactory technical use, but
are generally piled up in large heaps, and are regarded as a rather inconvenient
ballast.
After extensive trials, I have succeeded in finding out a method, that allows of
turning said residues into account; said method is based on the newly discovered
fact, that the said residues when combined with lime deliver a quickly- and well-
hardening compound.
In carrying my invention into effect, I first wash the residues, preferably with
aid of a filter-press, and I then remove the remaining contents of water
(about 50%), or more precisely a great portion of said water, by carefully applying
a rather low degree of heat to said washed residues, I call special attention to the
fact, that the binding- or holding-power of the cement to be produced is greatly
diminished, if the said residues become perfectly devoid of water. Said possibility
is already done away with, if the quantity of water remaining amounts to 10% only,
but I prefer to let the remainder of water amount to not less than 25% To have
a proper control of the drying, the latter should be performed slowly and watched
attentively.
In the next or last phase of my novel process the residues treated as above
stated are mixed with quick lime, and are ground together with the same; there
results a practically dry powder, the quick-lime having sucked up the whole
remainder of water above mentioned. Said powder is the cement to be produced;
the latter is just as good as the so-called Portland-cement, and may well be
subjected to the same tests as said latter.
Instead of using quick-lime, I may employ powdered bydrate of lime; I prefer,
however, the former, as otherwise the drying of the residues must be carried on
for a considerably longer time.
The proportion in the quantities of the components forming the cement may
vary according to the special employment, which the cement is intended for. In
general, I take equal parts of the two components in question; but if the cement
is intended for labours below water, or if it is to harden in very short a time, I then
use more residues than lime; if, on the other hand, the quality of the cement can
be a low one, I employ more lime thon residues. If, finally, the quick-lime
contains alumina, it is in either case advantageous to take less residues than
lime.
The manufacture of mortar from the cement in question is either carried on in
the usual manner consisting in mixing said cement with water and sand, or the said
cement (preferably mixed with water) is added to lime-mortar either during or
after the production of the same.

page_text: 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 I
claim is :-
1. The method of utilizing the residues resulting from the manufacture of
sulphate of alumina, consisting in freeing said residues from those components
that are soluble in water, and mixing the remainders with lime, for the purpose as
described.
2. The method of utilizing the residues resulting from the manufacture of
sulphate of alumina, consisting in freeing said residues from those components that
are soluble in water, and mixing the remainders with hydrate of lime, for the
purpose as described.
3. The method of utilizing the residues resulting from the manufacture of
sulphate of alumina, consisting in freeing said residues from those components that
are soluble in water; depriving the remainders of a part of their water, and
mixing them with lime, for the purpose as described.
4. The method of utilizing the residues resulting from the manufacture of
sulphate of alumina, consisting in freeing said residues from those components,
that are soluble in water; depriving the remainders of a part of their water by
exposing them to heat, and mixing them with quick-lime, for the purpose as
described.
Dated this 28th day of December 1805
MARTIN NAHNSEN,
By De Katow & Co.,
Agents for the Applicant.