A New or Improved Cement.
Year: 1899

page_text: Date of Application, 21st July, 1899
Complete Specification Left, 21st Apr., 1900-Accepted, 26th May, 1900
A New or Improved Cement.
I, WILLIAM ROBERTSON COCHRANE, of 37, Eglinton Street, in the County of
the City of Glasgow, Clerk, do hereby declare the nature of my invention
to be as follows:-
-
This invention has reference to and comprises a new or improved cement
adapted for building, plastering, concreting and similar purposes, and having the
qualities of Portland cement such as setting into a hard stone like mass after
being mixed with water, and which has the following advantages:-
Whiteness in colour, the capability of having the surface of the work brought
to a high finish and polish, that colouring materials can be more effectively
mixed with a white cement like this and more delicately and beautifully graded
than with ordinary cements in use, and that the, close smooth and polished
surface of the work which can be done with this cement renders it particularly
adapted for use in all classes of internal work for public buildings such as
hospitals, schools, halls, and the like; while it can also be very effectively em-
ployed in outdoor decorative work. It may also be usefully employed for fire-
places, hearths, and for mouldings and castings.
In carrying into practice my invention I employ a white lime or a chalk or
other limestone that will be white when calcined, in combination with a white
clay, such as the well known china clay or "kaolin" such as is procured in
Cornwall or wherever similar white clays are found; the proportions of these two
ingredients being from 58% to 66% of lime to 42% to 34% of clay, silicate of
alumina, and to this I add from 2% to 20% chloride of calcium or such an
addition of hydrochloric acid as will be capable of forming with the lime, chalk or
limestone employed 2% to 20% chloride of calcium, with or without an addition
to the first named proportions of lime, chalk, or limestone. The whole ingredients
are finely ground and intimately mixed, preferably under water or in a wet
condition, then dried and calcined to the point or almost to the point of incipient
vitrification. The resulting clinker is afterwards finely ground.
The ground cement is then with the addition of water, and if desired a propor-
tion of sand or similar material used to cheapen the mortar, wrought into a
stiff mortar and employed in the usual way, either for the building with bricks
or stones, or as a concrete for pavements, floors, walls, ceilings or wherever con-
crete made from ordinary Portland or like cement would be employed, or pre-
ferably it may be employed as a finishing coat after using the commoner and
less expensive cement for the body of the work. In which case to insure the
best results it should be used without the addition of any other material than
the necessary
amount of water and if wanted coloured
the necessary
The cement should
amount of colouring to produce the desired tint.
be used with the smallest proportion of water required to insure thorough
plasticity. The finishing coat should be rendered thoroughly smooth and level
before setting takes place, then after the cement has set thoroughly hard, at an
interval of from 2 or 3 days to a week, according to the conditions under which

page_text: the work has been done, the surface may be rought to a high degree of polish
by rubbing with a rubber of pumice stone or an exceedingly fine grained and
smooth sandstone or lime stone such as is used by lithographers or by a glass
or metal rubber. The polishing should be done dry and care taken to see that
whatever polishing or rubbing instrument is used it be thoroughly clean. The
polished surface can be kept clean by sweeping or dusting or washing with water
or soap and water without detriment.
A New or Improved Cement.
I, WILLIAM ROBERTSON COCHRANE, of 37, Eglinton Street, in the County of
the City of Glasgow, Clerk, do hereby declare the nature of my invention
and in what manner the same is to be performed to be particularly described
and ascertained in and by the following statement in writing: -
This invention has reference to and comprises a new or improved cement
adapted for building, plastering, concreting and similar purposes, and having the
qualities of Portland cement such as setting into a hard stone like mass after
being mixed with water, and which has the following advantages:-
Whiteness in colour, the capability of having the surface of the work brought
to a high finish and polish, that colouring materials can be more effectively
mixed with a white cement like this and more delicately and beautifully graded
than with ordinary cements in use, and that the close smooth and polished
surface of the work which can be done with this cement renders it particularly
adapted for use in all classes of internal work for public buildings such as
hospitals, schools, halls, and the like; while it can also be very effectively em-
ployed in outdoor decorative work. It may also be usefully employed for fire-
places, hearths, and for mouldings and castings.
66
"
In carrying into practice my invention I employ a white lime or a chalk or
other limestone that will be white when calcined, or any combination of such
lime, chalk or limestone as may be convenient, in combination with a white
clay, such as the well known china clay or kaolin such as is procured in
Cornwall or wherever similar white clays are found. The proportions of these
two ingredients may be from 58% to 66% of lime to 42% to 34% of clay, and
to this admixture I add from 1 or 2% to 20% chloride of calcium or such an
addition of hydrochloric acid as will be capable of forming with the lime,
chalk or limestone employed 1 or 2% to 20% preferably from 3% to 7% of
chloride of calcium, the proportions being regulated by the quality of the
materials used. The whole ingredients are finely ground and intimately mixed,
preferably under water or in a wet condition, then dried and calcined to the
point or almost to the point of incipient vitrification. The temperature of cal-
cination to be preferably kept as low as is compatible with the expulsion of the
carbonic acid from the carbonate of lime especially in any case when the higher
proportions of chloride of calcium or hydro-chloric acid are used. I have found
the best results to follow where a moderate heat was employed and continued
sufficiently long to expel all or the most of the carbonic acid, and to bring the
materials into that condition in which by the addition of water they unite or set

page_text: into a solid stone like body always stopping short of the point of vitrification
or partial vitrification. The resulting clinker is afterwards finely ground. To
insure the best results thorough incorporation of the several materials employed is
necessary in the preliminary stage namely, before firing and it is also most
important to have the calcined product ground to a fine powder.
The ground cement is then with the addition of water, and if desired a propor-
tion of sand or similar material may be used to cheapen the mortar, wrought
into a stiff mortar and employed in the usual way, either for the building with
bricks or stones, or as a concrete for pavements, floors, walls, ceilings, or wherever
concrete made from ordinary Portland or like cement would be employed, or pre-
ferably it may be employed as a finishing coat after using the commoner and
less expensive cements for the body of the work. In which case to insure the
best results it should be used without the addition of any other material than
the necessary amount of water and if wanted coloured the necessary amount of
colouring to produce the desired tint. The cement should be used with the
smallest proportion of water required to insure thorough plasticity. The finish-
ing coat should be rendered thoroughly smooth and level before setting takes
place, then after the cement has set thoroughly hard, at an interval of from 2
or 3 days to a week, according to the conditions under which the work has been
done, the surface may be wrought to a high degree of polish by rubbing with a
rubber of exceedingly fine grained and smooth sandstone, or lime stone, such
as is used by lithographers or by a glass or metal rubber. The polishing should
be done dry and care taken to see that whatever polishing or rubbing instrument
is used it be thoroughly clean. The polished surface can be kept clean by
sweeping or dusting or washing with water or soap and water without detriment.
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-
First. A cement composed of the ingredients and prepared by the process
substantially as herein described.
Second. A cement prepared from lime, chalk, or limestone and white clay,
with the addition of chloride of calcium or of hydrochloric acid substantially in.
the manner herein described.
Third. The addition to an admixture of lime, chalk, or limestone and white
clay, of chloride of calcium or of hydrochloric acid for the production of cement
by the process substantially as herein described.
Dated the 20th April 1900.
W. R. M. THOMSON & Co.,
96, Buchanan Street, Glasgow,
Agents.