A Process for the Treatment of Raw Materials to be used in the Production of Portland Cement.
Year: 1892

page_text: Date of Application, 2nd Mar., 1892
Complete Specification Left, 30th Nov., 1892-Accepted, 2nd Mar., 1893
AAD DI MOTTICATION.
[Communicated from abroad by DIE ACTIENGESELLSCHAFT
Copenhagen, in the Kingdom of Denmark.]
CIMBRIA," of
A Process for the Treatment of Raw Materials to be used in the
Production of Portland Cement.
I, JOHN THOMAS KNOWLES Manager to the firm of D. Young & Co. Patent
Agents 11 & 12, Southampton Buildings in the County of London do hereby
declare the nature of this invention to be as follows:-
Hitherto the raw materials from which Portland cement is produced by burning
have, as is well known been treated in such a manner that the component parts
thereof have been either buddled and then ground or have been first dried by
artificial heat or by means of a current of air, and then pulverized in order to be
subsequently mixed in suitable proportions ready for burning.
These two processes have the defect that, after the buddling, large quantities of
water have to be evaporated, while in the treatment by the dry process a good
deal of firing is required to dry up the component parts and free them from their
natural moisture, so that they may be finely divided by grinding.
After repeated experiments, and considerable expenditure, the communicators
have been fortunate enough to find a process whereby the raw materials such as
crude lime or chalk and clay may be finely pulverized and mixed without having to
use any of the processes hitherto resorted to.
The improved process consists in reducing by means of specially mounted rollers
or grinding mills and mixing machines or pug mills, the raw materials in their
natural moist condition to such a fine state of division that an intimate mixture may
be effected and after the said material has been subjected to a drying process and
freed partly or entirely from its natural moisture it can be forthwith burnt.
This special process is carried on as follows, viz. :--Clay and lime or chalk are
passed in their natural moist state, between large smooth rollers moving at different
speeds whereby such raw materials are broken up. Apart from being subjected to
the pressure of these rollers the raw materials are morcover subjected to a frictional
action or rubbing which assists in pulverizing the same. The spaces between the
rollers should not be larger than is necessary to so pulverize the raw materials that
a most intimate mixture thereof may be effected.
After this pulverizing operation the raw materials are mixed in suitable mixing
machines or pug.mills which, whether horizontal tubular machines or vertical
cylindrical receptacles, may work according to the same principle as ordinary
mixing machines.
The mixing is continued until the mass is thoroughly homogeneous after which
the raw materials are subjected to further treatment in a well-known manner to
bring them into such a condition as to be ready for burning.
Dated this 2nd day of March 1892.
D. YOUNG & Co.,
11 & 12, Southampton Buildings, London, W.C.,
Agents for the Applicant.

page_text: COMPLETE SPECIFICATION.
A Process for the Treatment of Raw Materials to be used in the
Production of Portland Cement.
I, JOHN THOMAS KNOWLES, Manager to the firm of D. Young & Co., Patent
Agents, 11 & 12 Southampton Buildings, in the County of London, 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 :-
Hitherto the raw materials from which Portland cement is produced by burning
have, as is well known been treated in such a manner that the component parts
thereof have been either buddled and then ground or have been first dried by
artificial heat or by means of a current of air, and then pulverized in order to be
subsequently mixed in suitable proportions ready for burning.
These, two processes have the defect that, after the buddling, large quantities of
water have to be evaporated, while in the treatment by the dry process a good
deal of firing is required to dry up. the component parts and free them from their
natural moisture so that they may be finely divided by grinding.
After repeated experiments, and considerable expenditure, the communicators
have been fortunate enough to find a process whereby the raw materials such as
crude lime or chalk and clay may be finely pulverized and mixed without having to
use any of the processes hitherto resorted to.
The improved process consists in reducing by means of specially mounted rollers
or grinding mills and mixing machines or pug mills, the raw materials in their
moist condition to such a fine state of division that an intimate mixture may be
effected and after the said material has been subjected to a drying process and
freed partly or entirely from its natural moisture it can be forthwith burnt.
This special process is carried on as follows viz. :-Clay and lime or chalk are
passed in their natural moist state, in a rolling mill containing large smooth rollers
moving at different speeds whereby such raw materials are broken up. Apart
from being subjected to the pressure of these rollers the raw materials are moreover
subjected to a frictional action or rubbing which assists in pulverizing the same.
The spaces between the rollers should not be larger than is necessary to so pulverize
the raw materials that a most intimate mixture thereof may be effected.
After these pulverizing or combined pulverizing and mixing operations, the raw
materials are mixed in suitable mixing machines or pug mills which, whether
horizontal tubular machines or vertical cylindrical receptacles, may work according
to the same principle as ordinary mixing machines.
cases.
The rolling mill is provided with ordinary smooth rollers which are adjustable
in such a manner that they can work closely one against the other. As a rule a
space of about millimeter is left between the said rollers to suit finely divided
material. The size of the rollers is optional and depends upon the class of work
which is required to be done, a diameter of from 500 to 800 millimeters and a
length of from 400 to 600 millimeters answering the purpose in the generality of
The speed at which the rollers revolve depends likewise upon circumstances
and upon
the amount of work required. A difference of from 10 to 20-revolutions
per minute between the speeds of the two rollers will cause a sufficient increase in
the grinding action. A preliminary mixture of the raw materials may be either
carried out in this mill by means of separate rollers and afterwards completed in
any suitable mixing machine. Or the raw materials may be supplied to the rollers
in suitable proportions by weight, in which case mixing can be carried on at
the same time as the grinding, the full and intimate mixture required for the
manufacture of cement must, however, take place in mixing machines.
The mixing is continued until the mass is thoroughly homogeneous, after which

page_text: the raw materials are subjected to further treatment in a well-known manner to
bring them into such a condition as to be ready for burning.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, as communicated to
me by my foreign correspondent I declare that what I claim is :-
The improved process for the treatment of the raw materials used in the manu-
facture of Portland cement, which process cousists in treating the said raw
materials in the moist state in which they are extracted from the quarries, by
pulverizing and intimately mixing them by means of rolling or grinding machines
and mixing machines or pug-inills, substantially as hereinbefore described.
Dated the 30th day of November 1892.
D. YOUNG & Co.,
11 & 12, Southampton Buildings, London, W.C.,
Agents for the Applicant.