Year: 1885

page_text: I, WILLIAM THOMAS TIMEWELL of Longbrook Cottage, Yealm Bridge Yealmpton
in the County of Devon, Portland Cement Maker do hereby declare the nature
of this Invention to be as follows:-
This Invention has for its object to make Cement from hard limestone such for
example as the hard White Limestone found in the Isle of White the Bath
freestone found in Wiltshire and Somersetshire the black white and other colored
stone called marble, mountain and other limestone found in Devonshire and the
Portland stone or other stone found in Dorsetshire or any other limestone that
contains over fifty per cent of Carbonate of Lime. I reduce the limestone selected
to a fine powder and mix with it silicated aluminous stone also reduced to a fine
powder or I mix with it fire clay, pipe clay, potters clay, porcelain clay or the
silicated mud from tidal rivers. When I use the tidal mud I especially prepare this
mud by washing it in an ordinary Cement Washmill separating therefrom all sand
and other objectionable matter-When the liquid mud leaves the washmill it goes
through several deposit pits in a continually running stream. When the liquid
leaves the last deposit pit it will be fine enough to run into reservoirs the fineness
being preferably such that it will pass a sieve preferably not less than 60 guage
3600 meshes to the square inch. The liquid is then allowed to remain until
settled down. The water supernatent is when clear drawn off and the deposit is
in a fit condition to be mixed with the powdered limestone.
I find that tidal muds, clays and silicated stone vary considerably in their
composition and in many instances are not in their original state adapted for
manufacturing cement in consequence of their deficiency in silica and alumina
I therefore analyse the silicated stone or mud or clay intended to be used and
having ascertained the proportions of silica and alumina therein, I if necessary
add to and mix with the tidal mud, clay or silicated stone, so much silica and
alumina as will form a mixture of the following proportions, Silica from 58 to
68 per cent and Alumina and iron from 18 to 24 per cent, which will be then
applicable to the manufacture of first class Portland Cement.
My process of securing a uniform mixture of silica and alumina is as follows.
I reduce silicated stone and aluminous stone to an impalpable powder using for
example the stone called blue elvin or other silicated stone found in Devon-
shire or flints glass granite stone, slate stone or other silicated aluminous eartha.

page_text: I then in a mixing machine mix it in the required proportions with either the
tidal mud or clay or silicated stone whichever is intended to be used with
sufficient water to wash the materials into a fine liquid through an ordinary
Cement washmill I then run it into reservoirs to settle and when the water is
clear I draw it off and the deposit is ready to be mixed with the powdered
limestone.
Then I proceed with the treatment of the limestone. When it contains over
10 per cent of water I dry that out, then reduce the stone to a fine powder through
millstone or roller mills so that it will pass through a sieve not less than
4 thousand holes to the square inch and that seventy five per cent of the same
shall pass through twenty thousand meshes to the square inch then I mix the
powdered limestone with one or more of the materials aforesaid using water and a
mixing machine and keep them agitated for a short time. I then pass the mixture
it through millstones to form a slurry and then I dry it on a drying floor and burn
in a cement kiln and then grind to a fine powder preferably so that it will pass
through a sieve of 2500 holes to the square inch to 5000 holes to the square inch
and so I produce a very good cement.
I prefer to use where possible a limestone that contains from 60 to 95 per cent
of Carbonate of lime and a silicated stone, clay or tidal mud that contains from 58
to 68 per cent of silica and from 18 to 24 per cent of iron and alumina or has this
proportion made up by added materials as herein before described.
The proportions of mixing these materials are guided by the quantity of
Carbonate of lime in the stone and the silica and alumina in the other materials
from three to four parts or five parts of Carbonate of lime by weight to one by
weight of silica and alumina allowing for the moisture in either of the materials.
By this improved process of making Cements when the materials are ready to
be made into Cement I do away with continually running mixtures and the
uncertainty of results incidental to the soft chalk processes.
According to my improved process I finish one mixture before I begin another
and thus I am enabled to produce in a comparatively short time a Cement of high
and regular quality.

page_text: Improvements in the Manufacture of Cement.
I WILLIAM THOMAS TIMEWELL of Longbrook Cottage, Yealm Bridge, Yealmpton
in the County of Devon Portland Cement Maker 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:-
This Invention has for its object to make cement from hard limestone such for
example as the hard White Limestone found in the Isle of Wight, the Bath
freestone found in Wiltshire and Somersetshire the Black White and other Colored
stone called Marble, mountain and other limestone found in Devonshire and the
Portland Stone or other stone found in Dorsetshire or any other limestone that
contains over sixty per cent of Carbonate of Lime. I reduce the limestone to a
fine powder and mix with it solicated aluminous stone also reduced to a fine
powder, or I mix with the powdered lime stone either fire clay pipe clay, potters clay,
porcelain clay or the silicated mud from tidal rivers. When I use the mud from
tidal rivers I especially prepare it by washing so as to separate therefrom all sand and
other objectionable matter which may be effected in an ordinary cement washmill.
As the liquid mud leaves the Washmill it is caused to pass in a continuous running
stream through several deposit pits until it is fine enough to be run into reservoirs
the fineness being preferably such that it will pass through a sieve of 60 guage
that is containing 3,600 meshes to the square inch The liquid is then allowed to
remain in the reservoirs to settled down until the supernatent water is clear which
is then drawn off, the deposit being then in a fit condition to be mixed with the
powdered limestone,
I have found that tidal muds, clays and silicated stone vary considerably in
their composition and in many instances are not, in their original state, adapted
for Manufacturing Cement in consequence of their deficiency in silica and alumina,
I therefore analyse the silicated stone, or mud, or clay intended to be used and
having ascertained the proportions of Silica and Alumina contained therein, I if
necessary add there to so much silica and alumina as will form a mixture of the
following proportions videlicit Silica from 58 to 68 per cent and Alumina and Iron
from 18 to 24 per cent which will be then applicable to the manufacture of first
class Portland Cement.
In order to secure a uniform mixture of Silica and Alumina I reduce silicated
stone and aluminous stone to an impulpable powder using for example the stone
called blue elvin or other silicated stone found in Devonshire, or flint Glass,
Granite stone, slate stone or other silicated aluminous earths. then mix there-
with in a suitable machine the required proportions of either the tidal mud or clay,
or silicated stone (which ever is intended to be used) with sufficient water to reduce
the materials to a fine liquid in an ordinary cement washmill I then run the
mixture into reservoirs to settle and when the water is clear it is drawn off and
the deposit is then ready to be mixed with the powdered limestone.
When the limestone contains over 10 per cent of water I dry out the excessive
moisture and then reduce the stone to a fine powder by means of millstones or
roller mills, so that it will pass through a sieve containing 4 thousand holes to the

page_text: square inch or so that at least seventy five per cent of the powder shall be
sufficiently reduced to pass through twenty thousand meshes to the square inch
I then mix the powdered limestone with one or more of the materials aforesaid and
water in a mixing machine and keep them agitated for a short time. I then pass
the mixture through millstones to form a slurry and then dry it on a drying floor.
When the slurry is sufficiently dry it is burnt in a cement kiln and then ground
to a fine powder preferably so fine that it will pass through a sieve of 2500 to
5000 holes to the square inch thus a very good cement is produced.
I prefer to use limestone that contains from 60 to 95 per cent of Carbonate of
lime and silicated stone, clay or tidal mud that contains from 58 to 68 per cent of
Silica and from 18 to 24 per cent of iron and Alumina or that has this proportion
made up by added materials thereto as hereinbefore described.
The proportions of the material to be mixed are determined by the quantity of
Carbonate of lime contained in the stone and the Silica and Alumina in the other
materials, from three to five parts of Carbonate of lime by weight to one by
weight of Silica and Alumina is a good proportion allowing for the moisture in
either of the materials.
By this improved process of making cements I do away with continually running
mixtures and the uncertainty of results incidental to the soft chalk processes.
I prefer to finish one mixture before I begin another so as to ensure the
production in a comparatively short time of a cement of high and regular quality.
In carrying out my process, instead of using all wire sieveing, I prefer to use a
blower or Fan to blow out first the impalpable powder from the ground limestone
or the ground flint Glass or Granite stone or slate stone. Before mixing the
ground materials I separately convey them to a Bin of a sufficiently funnel shape
that will keep the materials continually running unto a shaking feed long enough
to deliver the ground material into a thin stream in front of the blower or fan
which blower should be driven at a high speed so as to blow the impalpable
powder into a stive or collecting chamber. This collecting chamber is preferably
divided into three compartments into the first of which compartments or that
nearest the blower the coarsest together with some of the finer ground materials
fall and pass from thence into a dressing machine or diagonal sieve placed under
this compartment the sieve by preference being constructed of from 60 to 70 gauge
wire or with meshes of from 3,600 to 4,000 to the square inch so as to separate the
fine from the coarser material. The fine material thus separated is about 15 per
cent of the whole and I mix it with the impalpable powder before mixing with
any other material.
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 manufacture of cement from hard limestone and silicated aluminous matter
or tidal mud containing silica and alumina with or without the addition of silica
and alumina substantially as hereinbefore defined.