Improvements in the Manufacture of Portland Cement.
Year: 1899

page_text: Date of Application, 4th Mar., 1899
Complete Specification Left, 2nd Dec., 1899-Accepted, 20th Jan., 1900
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Portland Cement.
I, LEEDHAM WHITE, of 2, Lime Street Square, in the City of London, Cement
Manufacturer, do hereby declare the nature of this invention to be as follows:-
In the manufacture of Portland cement it has before been proposed to add
coal, coke or breeze, or other suitable fuel to the chalk and clay from which the
cement is to be made, and to grind these materials together before loading them
into the kilns, such powdered fuel replacing the whole or a portion only of the
coal or coke usually loaded into the kilns along with lumps or pieces of dried
slip or slurry or with bricks made of the raw material from which cement is
manufactured.
No entirely satisfactory results have however so far been obtained from such
use of powdered fuel nor has this process been widely adopted for the reason
that in kilns of ordinary construction the draught is insufficient to ensure perfect
and regular combustion of such powdered fuel mixed with the chalk and clay.
According to my invention I mix the fuel in a powdered state with the slurry
in the washmill, or grind the fuel in suitable proportions with the slurry, or
other material from which cement is to be manufactured, and afterwards dry
and burn the mixture in what are known as rotary or revolving furnaces, whereby
owing to the perfect draught which is obtained complete combustion takes place,
in the right place, and at the right time, of the fuel so mixed with the raw
materials as described.
Preferably I use 25 or 30 % of the weight of the cement as fuel, but I do
not confine myself to these proportions.
The blast of the rotary furnaces may be artificially increased and the fuel
ground with or mixed in a powdered state with the raw material may be supple-
mented by other solid, liquid or gaseous fuel burnt in the furnace.
A great saving in fuel is effected by this process over the methods in use with
kilns of ordinary construction, even as compared with the method of burning
cement in rotary kilns as at present practised some saving is effected in economy
of labour and in the greater output of cement obtained.
Dated this 3rd day of March 1800

page_text: the same is to be performed to be particularly described and ascertained in and
by the following statement:-
In the manufacture of Portland cement it has before been proposed to add
coal, coke or breeze, or other suitable fuel to the chalk and clay from which the
cement is to be made, and to grind these materials together before loading them
into the kilns, such powdered fuel replacing the whole or a portion only of the
coal or coke usually loaded into the kilns along with lumps or pieces of dried
slip or slurry or with bricks made of the raw material from which cement is
manufactured.
No entirely satisfactory results have however so far been obtained from such
use of powdered fuel nor has this process been widely adopted, for the reason
that in kilns of ordinary construction the draught is insufficient to ensure perfect
and regular combustion of such powdered fuel mixed with the chalk and clay.
According to my invention I mix the fuel in a powdered state with the slurry
in the washmill, or grind the fuel in suitable proportions with the slurry, or
other material from which cement is to be manufactured. and afterwards dry
and burn the mixture in what are known as rotary or revolving furnaces, whereby
owing to the perfect draught which is obtained complete combustion takes place,
in the right place and at the right time, of the fuel so mixed with the raw
materials as described.
Preferably I use 25 or 30% of the weight of the cement as fuel, but I do
not confine myself to these proportions.
The blast of the rotary furnaces may be artificially increased and the fuel
ground with or mixed in a powdered state with the raw material may be supple-
mented by other solid, liquid or gaseous fuel burnt in the furnace.
A great saving in fuel is effected by this process over the methods in use with
kilns of ordinary construction, even as compared with the method of burning
cement in rotary kilns as at present practised some saving is effected in economy
of labour and in the greater output of cement obtained.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is:-
-
The process of manufacturing Portland cement, consisting in mixing powdered
fuel with the slurry, drying the mixture and burning it whilst in a state of
agitation.
Dated this 30th day of November 1899.
LEEDHAM WHITE.