Improvements in and relating to the Manufacture of Lime and of Natural and Artificial Cements.
Year: 1888

page_text: Date of Application, 9th Feb., 1888
Complete Specification Left, 9th Nov., 1888
Complete Specification Accepted, 21st Dec.,
1888
Improvements in and relating to the Manufacture of Lime and of
Natural and Artificial Cements.
I, MATTHEW HENRY HEYS of Galley Hill, Swanscombe in the County of Kent,
Schoolmaster do hereby declare the nature of this Invention to be as follows:-
This Invention relates to the manufacture of lime and of natural and artificial
cements and these improvements consist primarily in the method of burning or
calcining the limestone, chalk, slurry or other raw material and secondarily in the
subsequent treatment of the burnt or calcined inaterial.
The raw material is packed with fuel in a kiln in the usual or in a similar manner to
that commonly employed but instead of igniting the fuel at the bottom of the kiln
and allowing it to burn upwards, I ignite the fuel at the top of the charge and cause it
to burn downwards. As soon as the fuel is burnt through to the bottom I close the
eye of the kiln so as to prevent access of air. After cooling, the calcined material
may be ground to a fine powder and gauged similarly to cement or plaster with or
without the previous admixture of other substances therewith.
I generally prefer however to moisten the calcined material before or after grinding
and to employ this material as plaster or Cement alone, or mixed with other suitable
substances.
When I mix such other substances with the calcined material whether or not it h
been previously moistened I prefer to employ Silica, Silicate of Aluminia, Magnesite
or a mixture of chalk and clay calcined or similar materials or compounds.
ROD
WILLIAM E. HEYS,.
Agent for the Applicant.

page_text: Improvements in and relating to the Manufacture of Lime and of
Natural and Artificial Cements.
I, MATTHEW HENRY HEYS of Galley Hill, Swanscombe in the County of Kent,
Schoolmaster, 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 relates to the manufacture of lime and of natural and artificial
cements, and these improvements consist chiefly in the method of burning the raw
material such as chalk, limestone, or other suitable material consisting principally of
lime, and secondarily in the subsequent treatment of the calcined product.
The raw material may most conveniently be burnt or calcined in a kiln similar to the
kilns in which hydraulic cement is usually burnt, but it is necessary to erect or provide
at the eye of the kiln, a door, damper, screen, or other similar device by means of
which access of the air to the kiln may be regulated at will or be altogether excluded.
Doors or dampers may also be fitted to the openings in the kiln above the charge, or
the charging holes may be bricked up after the kiln is loaded and the outlet of the flue
be governed by a damper.
In charging the kiln, there is first laid upon the grate a thick bed of fuel such as
gas coke; upon this there is laid a layer of the raw material, amongst which there may
advantageously be distributed a small quantity of breeze. Over this layer there is
then laid a layer of coke or other suitable fuel, and then another layer of the raw
material and successive alternate layers of the raw material and fuel until the charge
is completed. It is important that in each of the layers of the raw material, there should
be thin walls or columns of fuel such as coal nuts, capable of comparatively easy
ignition. These walls or columns of fuel must connect the layer of fuel above with the
layer of fuel below and thus serve as a means for communicating the fire downwards.
The walls or columns of fuel may conveniently be made by placing in the layer of raw
material, concentric vertical open ended tubes with their lower ends resting upon the
layer of fuel below. When the full thickness of the layer of raw material has been
placed around the outer tube and within the inner tube, the space between the tubes
is filled with the fuel and they may then be withdrawn, leaving a circular wall or
column of fuel. These rings or walls of fuel may be one and a half to three inches
thick, and from nine to eighteen inches in diameter, but these dimensions will in all
cases be governed by the nature of the fuel and raw material; by the dimensions of
the kiln and by other local conditions. The total fuel required for the charge will
generally be from twenty-five per cent. to forty per cent. more than is required for
burning lime in the ordinary manner, but a considerable quantity of the fuel is a
recovered unconsumed after calcination.
The kiln having been charged in the manner hereinbefore described, a brisk fire is
lighted upon the upper surface of the top layer, the charging openings are closed and
air is freely admitted at the eye or bottom of the kiln. When the charge has burnt

page_text: through to the bottom, that is to say as soon as the fire is visible at the eye of the
kiln, the doors or dampers at the eye of the kiln are closed so as to practically cut off
the supply of air to the burning charge. It is almost impossible and not desirable to
make these doors or dampers absolutely airtight, and it is sufficient if they are so tight
as to prevent the access of air in such quantities that no uncombined oxygen will pass
through the incandescent fuel at the bottom of the kiln. The charge may be with-
drawn in the usual manner after it has cooled sufficiently, but no free air should be
admitted to the incandescent charge.
The calcined product may be ground to powder and used as ordinary plaster or
cement, but I prefer to coarsely crush it and allow it to air slake for a few days.
The free lime may then be sifted or winnowed from the unslaked portions which may
if desired, be more finely ground for use. This material forms an excellent substitute
for plaster of paris and may be used in a similar manner. Instead of air slaking, the
lumps of calcined material may be sprinkled or instantaneously dipped in water, when
the free lime will slake to powder more rapidly; the slaked lime can then be sifted out
and the hard residue be ground for use.
The slaked lime may be mixed as a slurry with silicates of alumina alone or
in combination with silica and be dried and reburnt in the manner hereinbefore
described.
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 :-
:-
(1.) The herein before described method of burning or calcining natural and artificial
raw material consisting principally of carbonate of lime such as chalk and limestone,
argillaceous limestone, magnesian limestone, or dried cement slurry, for the manufacture
of lime or cement; substantially as described.
(2.) Subjecting the products of the hereinbefore described method of calcination to
the action of moisture and separating the slaked from the unslaked portions, thereafter
grinding the unslaked portions for use as plaster, and, if desired, mixing the slaked
portion with silicious material and re-calcining it, substantially as hereinbefore
described.
Dated this 8th day of November AD 1080
WILLIAM E. HEYS,
Agent for the Applicant.