Improvements in the Manufacture of Portland Cement.
Year: 1894

page_text: Date of Application, 23rd Jan., 1894
Complete Specification Left, 20th Oct., 1894-Accepted, 24th Nov., 1894
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Portland Cement.
I, ALEXANDER MCARA of 65 Morrison Street in the City of Glasgow, Lime
and Cement Merchant, do hereby declare the nature of this invention to be as
follows:-
This invention has for its object the production of Portland cement of superior
quality in a simple and inexpensive manner.
In lieu of the well known processes of mixing soft materials such as chalk and
clay by means of a wash mill or of grinding together hard materials such as
limestone and shale I grind argillaceous and silicious limestones such as the arden
stone having approximately the proportions of ingredients necessary for making
Portland cement into a fine powder by means of millstones or other pulverising
machinery and I add thereto the following ingredients in the form of slip or slurry.
If the powder is too poor in lime I add in a liquid or semi-liquid state sufficient
wet slip or slurry of rich lime or chalk to bring up the necessary strength of
carbonate. If the powder is too rich in lime I add in a liquid or semi-liquid state
soft limey blaes or shale such as the deposit found above the arden limestone.
liquid slip or slurry is added to the pulverised lime in sufficient quantities to make
a thick paste by means of horizontal and vertical pug mills in a condition ready for
the drying floor where it is dried in the usual way ready for the kilns.
Dated this 22nd day of January 1894.
The
CRUIKSHANK & FAIRWEATHER,
62, Saint Vincent Street, Glasgow, Agents.
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Portland Cement.
1, ALEXANDER MCARA, of 65 Morrison Street, in the City of Glasgow, Lime
and Cement Merchant, 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 the production of Portland cement of superior
quality in a simple and inexpensive manner.
In lieu of the well known processes of mixing soft materials such as chalk and
clay by means of a wash mill or of grinding together hard materials such as
limestone and shale I grind argillaceous and silicious limestones such as the arden
stone having approximately the proportions of ingredients necessary for making
Portland cement into a fine powder by means of millstones or other pulverising
machinery and I add thereto the following ingredients in the form of slip or slurry.
If the powder is too poor in lime I add in a liquid or semi-liquid state sufficient
wet slip or slurry of rich lime or chalk to bring up the necessary strength of
carbonate. If the powder is too rich in lime I add in a liquid or semi-liquid state
soft limey blaes or shale such as the deposit found above the arden limestone. The
liquid slip or slurry is added to the pulverised lime in sufficient quantities to made
a thick paste by means of horizontal and vertical pug mills in a condition ready for
the drying floor where it is dried in the usual way ready for the kilos.

page_text: The ground limestone and slip are preferably used in such proportions as will
produce a mixture containing from about 74 to 78 per cent. of carbonate of lime, the
quantities of each being regulated by the proportion of carbonate of lime in the
limestone used; but I do not restrict myself to these proportions.
Having now particularly described and ascertained the nature of my said inven- 5
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. The manufacture of Portland cement, substantially as described.
2. In the manufacture of Portland cement the use in combination or admixture
of argillaceous and silicious limestones ground into powder and a wet slip or slurry
composed of either rich carbonate of lime or soft limey blaes or shale substantially
as and for the purpose set forth.
Dated this 10th dose of
La 1004
CRUIKSHANK & FAIRWEATHER,
62, Saint Vincent Street, Glasgow, Agents.