Improvements in and Connected with the Manufacture of Cements.
Year: 1888

page_text: Date of Application, 16th July, 1888
Specification Accepted, 17th Aug.. 1888
COMPLETE SPECIFICATION.
Improvements in and Connected with the Manufacture of Cements.
We GEORGE JAMES SNELUS of Workington in the County of Cumberland
Metallurgist THOMAS GIBB of Jarrow in the County of Durham Manufacturing
Chemist JOHN CAMERON SWAN of the City and County of Newcastle on Tyne
Merchant HERBERT SMITH of the City and County of Newcastle on Tyne Merchant
and WILLIAM WHAMOND of Jarrow aforesaid Doctor of Medicine 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 that is to say :-
The object of this Invention is to provide a cheap and reliable cement of the class
known as Portland Cement.
According to this Invention we take Blast Furnace Slag which has been granulated
by being brought whilst in the molten state into contact with water. This granulated
slag we partially dry which may be effected most conveniently by passing it on an
endlass band between rollers which squeeze out the surplus water.
We then calcine
the said slag which can be effected by any convenient method for instance by heating
it in an oxidizing atmosphere on the bed of any of the forms of calcining furnace used
in calcining ores but we preferably use a vertical furnace of the character of the
Gerstenhofer Kiln The objects of calcining the slag are to get rid of all water free
and combined and to oxidize the calcic Sulphide present in the slag. We find that if
the granulated slag be not calcined any water left in it is detrimental to the keeping
quality of Cement made from it, whilst if the calcic Sulphide be not oxidized it is
subject to gradual decomposition when the cement is exposed to moisture it then
giving off noxious fumes of sulphuretted hydrogen and causing disintegration.
We make a frit essentially of Lime and Alumina but with some Oxide of iron and
Silica by burning a mixture of Aluminous ore and lime or rich Aluminous clay and
Lime. This frit we can most conveniently make by mixing the ingredients in a mill
moulding the same into bricks and burning in ordinary Kilns. The proportions
used should be varied in accordance with the character of the slag with which it is to
be employed but we find generally 3 parts of Lime and 2 parts of rich Aluminous
Irish ore to be very suitable proportions.

page_text: We then grind together the aforesaid calcined slag and calcareous frit to produce
cement using for this purpose any ordinary or suitable grinding or reducing
apparatus. We find that eight parts of the said calcined slag resulting from the
manufacture of Hematite pig iron mixed with one part of the said Calcareous frit
forms a high class cement but we do not limit ourselves to these proportions: A
good cement may be formed by grinding the aforesaid calcined blast Furnace slag
alone or in conjunction with cement making materials other than or in addition to the
frit hereinbefore described.
Having now particularly described and ascertained the nature of our said Inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
First. In the manufacture of Cement partially drying the aforesaid granulated
Blast Furnace Slag by passing it on a continuous band between rollers to squeeze
out water as aforesaid.
Second. In or for the manufacture of Cement the use of Blast furnace slag granu-
lated and calcined as aforesaid.
Third. In or for the manufacture of cement the preparation and use of a Calcareous
Aluminous frit substantially as herein before explained.
Fourth. The manufacture of Cement by the mixing or grinding together of
calcined blast furnace slag and calcareous Aluminous frit substantially as hereinbefore
described.
Eifth. As new articles of manufacture the cements manufactured as herein described
and claimed.