IMPROVEMENTS IN THE MANUFACTURE OF PORTLAND AND OTHER CEMENTS
Year: 1852

page_text: LETTERS PATENT to William Aspdin, of Blackwall, Gateshead-
upon-Tyne, in the County of Durham, Cement Manufacturer, for
the Invention of "IMPROVEMENTS IN THE MANUFACTURE OF PORTLAND
AND OTHER CEMENTS"
Sealed the 9th March 1858, and dated the 22nd December 1852.
PROVISIONAL SPECIFICATION left by the said William Aspdin at
the Office of the Commissioners of Patents, with his Petition, on
the 22nd December 1852.
I, WILLIAM ASPDIN, of Blackwall, Gateshead-upon-Tyne, in the
County of Durham, Cement Manufacturer, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN THE MANUFACTURE OF
PORTLAND AND OTHER CEMENTS" to be as follows:-
Alkali refuse is composed of three parts sulphuret of lime, the
remainder is small coke, with a minute portion of carbonate of soda.
The above refuse is well mixed in water, to the consistence of cream,
with argillaceous earth of any kind, in the proportions of six parts of
the former to one of the latter. It is then run off into "backs"

page_text: "troughs" to subside. The upper or liquid part is again run off into
shallow vats, in which the carbonate of soda crystallizes, and the
sulphur in solution as a sulphuret of lime is deposited. The residue in
the "backs" is then removed into drying flues heated by fire or steam,
from thence into kilns, where it is calcined and vitrified, and when
cold is ground to a fiue powder.
Further, the alkali refuse, as it comes from the manufacturer, without
any admixture, is dryed by the action of the air or on the flues, is then
removed into the kilns where the sulphur is sublimed into a fire-brick
dome, cone, or flues; what remains in the kilns is thoroughly calcined,
and when cold is ground to a fine powder, and mixed with the powder
obtained from the former process, in equal proportions.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Aspdin in the Great Seal Patent Office,
on the 15th June 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
WILLIAM ASPDIN, of Blackwall, Gateshead-upon-Tyne, in the County
of Durham, Cement Manufacturer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Fer
Letters Patent, hearing date the Twenty-second day of December, in
the year
of our Lord One thousand eight hundred and fifty-two, in the
sixteenth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said William Aspdin, Her special licence
that I, the said William Aspdin, my executors, administrators, and
assigns, or such others as I, the said William Aspdin, my executors,
administrators, and assigns, should at any time agree with, and no
others, from time to time and at all times thereafter during the
term therein expressed, should aud lawfully might make, use, ex-
ercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man. an Invention for

page_text: "IMPROVEMENTS IN THE MANUFACTURE OF PORTLAND AND OTHER CEMENTS,"
upon the condition (amongst others) that I, the said William Aspdin,
by an instrument in writing under my hand and seal, should particu-
larly describe and ascertain the nature of the said Invention, and in
what manner the same was to be performed, and cause the same
to be filed in the Great Seal Patent Office within six calendar months
next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said William Aspdin, do hereby
declare the nature of the said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement thereof (that is to say):
This Invention consists of treating alkali refuse, and manufacturing
Portland and other cements from products thereof. The above refuse
is well mixed in water to the consistence of cream, and ground in like
manner to that in which clay has been washed and ground when for
the manufacture of bricks, and a small quantity of argillaceous earth,
say about one in seven, may be mixed therewith. When the materials
are well washed they are run off into backs or troughs to subside. The
upper part of the liquid is again run off and preserved, in order, when
it is thought desirable, to crystallize the carbonate of soda therein, and
to obtain any sulphur which may be present.
The matters which settle in the backs or troughs are made up in
lumps and dried; they are then to be calcined and vitrified, and after-
wards ground to a fine powder. It is not absolutely essential that the
alkali refuse should be ground in water, as it may be made up in lumps,
dried, calcined, and vitrified, without undergoing such process. I, how-
ever, prefer to grind and wash the alkali refuse, as herein described,
before subjecting the same to the process of heat, as explained. By
the treatment of alkali refuse, as first above described, Portland cement
of an excellent quality is made from this waste and cheap material, by
which the manufacture of such cements will therefore be cheapened
and improved; and, by omitting the process of grinding, and wash-
ing: other and cheaper cements, and of qualities depending on the
alkaline refuse used, will be manufactured, but inferior to Portland
cement.

page_text: Having thus described the nature of my Invention, and the manner
of performing the same, I would have it understood that what I
claim is the manufacture of Portland and other cements from alkaline
waste.
In witness whereof, I, the said William Aspdin, have hereunto set
my hand and seal, this Tenth day of June, in the year of
our Lord One thousand eight hundred and fifty-three.
WILLIAM ASPDIN. (L.S.)
Witness, WILLIAM DUNN,
Sol, Newcastle-upon-Tyne.