IMPROVEMENTS IN THE MANUFACTURE OF CEMENT
Year: 1856

page_text: LETTERS PATENT to Charles Durand Gardissal, of 10, Bedford Street,
Strand, London, and of 29, Boulevart St. Martin, Paris, Patent Agent,
for the Invention of "IMPROVEMENTS IN THE MANUFACTURE OF CEMENT."
_ A communication.
-
PROVISIONAL SPECIFICATION left by the said Charles Durand Gardissal
at the Office of the Commissioners of Patents, with his Petition, on the
3rd October 1856.
CHARLES DURAND GARDISSAL, of 10, Bedford Street, Strand, London,
and of 29, Boulevart St. Martin, Paris, Patent Agent, do hereby declare
the nature of the said Invention for "IMPROVEMENTS IN THE MANUFACTURE OP
CEMENT," (a communication,) to be as follows:
Lime, clay, and a small quantity of one or several of the salts herein-after
mentioned are the elements of the cement manufactured according to this
Invention, and I combine them in one calcining operation, which process
differs essentially from the process by which certain mastics or cements are
obtained by the expensive process of combining lime with solutions of alkaline
silicates.
I begin by combining clay and lime in such proportions that after com-

page_text: bination the mixture contains about one-half quick lime and the other half
clay. I increase or decrease the proportion of the clay according as I require
the cement to set slowly or quickly. To obtain this combination economically,
I use as much as possible marls having the requisite proportion of clay and
lime. If the marl has two much lime I add clay to it; if it is too clayey.
I mix with it some slacked lime or chalk, but always in such manner as to
obtain as near as possible the proportions above stated. To this point my
mode of proceeding differs but little from that usually practised for the
manufacture of artificial hydraulic lime.
The essential point in the manufacture, and of which this Invention
principally consists, is this, that instead of manufacturing the mixture of lime
and clay with water only, as is the case according to the ordinary method of
preparing artificial hydraulic lime, I previously dissolve in the water used
one or several of the salts of magnesia, potassium, or soda, but, by preference,
I use common salt, in the proportion of from 1 to 3 lbs. of salt to every
100 lbs. of cement to be manufactured. The proportion of 1 to 2 lbs. is the
proportion I generally use; this proportion may, however, be diminished,
according to the nature of the clay that is to be acted upon, or if a very quick
setting cement is not required.
If convenient, sea water may be used in its natural state or may be con-
centrated; the saline waters of, salt manufactories are also. applicable; also
the refuse waters from the washing of wood or coal ashes, and even ashes
themselves; clay "naturally saturated with salts of magnesia, of potassium, or
of soda may be used. In all cases I take care that the clay, the lime, and
the salt may be (after the calcination of the cement) in the above stated
proportions. To render the mixture of clay, lime, and salt as perfect as
possible, I dilute & levigate these matters in a circular vessel by means of
edge runners actuated by any motive power; as soon as I have by these
means obtained a homogeneous mass I run it through canals leading to
suitable reservoirs or basins. When the deposit becomes compact, and while
yet plastic, I quickly mould this material into the form of bricks. These
bricks are placed on their edges upon a firm soil until they are partially dry,
but without waiting until they are completely so I proceed with the burning
or calcining operation, which I conduct in ordinary ovens (at a dark red
heat) with a moderate fire. If, instead of salts of potassium, magnesia, or
soda (carbonate or sulphate) I use common salt (chloride of sodium), I take
care before calcining to let the mixture rest during several days in a rather
damp place, in order to decompose the chloride of sodium by the action of
the lime, and thereby obtain artificial "natron," which will act upon the

page_text: clay; (the chlorine of the chloride of calcium will be evolved in the presence
of fire;) common salt will also act upon the clay. If I use ferruginous clay
or marl during the operation of burning, the peroxide of iron will change
into volatile perchloride of iron, and soda will be produced, which will combine
with the silica or alumina of the clay.
Lastly, the common salt will also act on the clay of the mixture if I take
care to burn the bricks in a damp state, for in the presence of fire and of
chloride of sodium the vapour of water will furnish bydrogen to the chlorine
and oxygen to the sodium, which being transformed into soda will furnish the
silicate and the alumina required. Thus, the three methods which I have
described for the use of common salt in the manufacture of cement may be
substituted one for the other, at the will of the manufacturer, and will all
succeed. Of the above-mentioned salts I prefer common salt, from motives
of economy and for the better effects produced, which are probably to be
attributed to the soda acting in its primitive state. Like natural cements,
my manufactured cements, after having been subjected to the proper degreo
of heat in calcination, are pulverised and sifted, and kept in well closed
barrels or other vessels. For use it is treated like natural cements and
plaster, and may be used for a variety of purposes. I may add, that if I
wish to obtain a colored cement I put into the mixture of lime, clay, and
salt metallic oxydes to produce the required colours, the whole being subjected
to calcination. If instead of plastic cement I wish to obtain artificial puzzolan,
I simply mix the salt with clay, & heat or burn and pulverise it in the
ordinary manner.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Charles Durand Gardissal in the Great Seal Patent Office
on the 1st April 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
DURAND GARDISSAL, of 10, Bedford Street, Strand, London, and of No. 29,
Boulevart St. Martin, Paris, Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Third day of October, in the year of our Lord
One thousand eight hundred and fifty-six; in the twentieth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Charles Durand Gardissal, Her special licence that I, the said Charles Durand
Gardissal, my executors, administrators, and assigns, or such others as I, the

page_text: said Charles Durand Gârdissal, my executors; administrators, and assigns, should
at any time agree with, and no others, from time to time and at all times there-
after during the term therein expressed; should and lawfully might make,
use, exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for IMPROVEMENTS
IN THE MANUFACTURE OF CEMENT," a communication, upon the condition
(amongst others) that I, the said Charles Durand Gardissal, my executors
or adininistrators, by an instrument in writing under my, or their, or one of
their lands and seals; should particularly 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 witliin
six calendar months next and immediately after the date of tlie said Letters
Patent.'
NOW KNOW YE; that I, the said Charles Durand Gardissal, do liereby
declare the nature of the said Invention, and in what manner the same is to
lie performed, to be particularly described and ascertained' iii and by the
following statement, that is to say :---
Lime, clay, and a small quantity of one or several of the salts herein-after
mentioned are the elements of the cement manufactured according to this
Invention, and I combine them in one calcining operation, which process
differs essentially from the process by which certain mastics or cements are
obtained' by the expensive process of combining lime with solutions of alkaline
silicates:
I begin by combining clay and lime in such proportions that' after com-
bination the mixture contains about one-half quick lime and the other half
clay. I increase or decrease the proportion of the clay according as I require.
the cement to set slowly or quickly. To obtain this combination economically
I use as much as possible marls having the requisite proportions of clay and
lime. If the marl has too much lime I add clay to it; if it is too clayey
I mix with it some slacked lime or chalk, but always in such manner as to
obtain as near as possible the proportions above stated..
To this point my mode of proceeding differs but little from that' usually
practised for the manufacture of artificial hydraulic lime.
Tlie essential point in the manufacture, and of which this Invention principally
consists, is this, that instead of manufacturing the mixture of liñie' and' clay
with water only, as is the case according to the ordinary method of preparing
artificial hydraulic lime or cement; I previously dissolve in the water' used
one or several of the salts of magnesia, potassium, or soda, but, by preference,
I'use common salt, in the proportion of from one to three pounds weiglit of

page_text: salt to every hundred pounds-weight of cement to be manufactured. The
proportion of one to two pounds weight is the proportion I generally use:;
this proportion may however, be diminished according to the nature of the
clay, that is to be acted upon, or if a very quick setting, cement is not required.
If convenient, sea water may be used in its natural state or may be con--
centrated; the saline waters' of salt manufactories are also applicable; also
the refuse waters from the washing of wood or coal ashes; and even ashes
themselves; clay naturally saturated with salts of magnesia, of potassium,; or
of soda may be used. In all cases I take care that the clay, the lime, and
the salt may be after the calcination of the cement. in the above stated
proportions. To render the mixture of clay, lime, and salt, as perfect as
possible, I dilute and. levigate these matters in a circular vessel by means of
edge: runners actuated' by any motive power. As soon as I have by these
means obtained a homogeneous mass I run it through canals leading. to
suitable reservoirs or basins, when the deposit becomes compact; and while
yet plastic I quickly mould this material into the form of bricks. These
bricks are placed on their edges upon a firm soil. until they are partially dry,
but without waiting until they are completely so I proceed with the burning
or calcining operation, which I conduct in ordinary ovens at a dark red heat
with a moderate fire: If; instead of salts of potassium; magnesia; or soda
(carbonate or sulphate), I use common salt (chloride of sodium), I take care
before calcining to let the mixture rest during several days in a rather damp
place, in order to decompose the chloride of sodium by the action of the
lime, and thereby obtain artificial natron, which will act upon the clay; (the
chlorine of the chloride of calcium will be evolved in the presence of fire;
common salt will also act upon the clay. If I use ferruginous clay or marl
during the operation of burning, the peroxide of iron will change into volatile
perchloride of iron, and soda will be produced, which will combine with the
other silica or alumina of the clay. Lastly, the common salt will also act on the
clay of the mixture if I take care to burn the bricks in a damp state, for
in the presence of fire and of chloride of sodium the vapour of water will
furnish hydrogen to the chlorine and oxygen to the sodium, which being
transformed into soda will furnish the silicate and the alumina required.
Thus, the three methods which I have described for the use of common salt in
the manufacture of cement may be substituted one for the other at the will
of the manufacturer, and will all succeed. Of the above-mentioned salts I
prefer common salt, from motives of economy and for the better effects produced,
which are probably to be attributed to the soda acting in its primitive state.
Like natural cements, my manufactured cements, after having been sub-

page_text: jected to the proper degree of heat in calcination, are pulverised and sifted,
and kept in well closed barrels or other vessels. For use it is treated like
natural cements and plaster, and may be used for a variety of purposes. I
may add, that if I wish to obtain a colored cement I put into the mixture of
lime, clay, and salt metallic oxides to produce the required colours, the whole
being subjected to calcination. If instead of plastic cement I wish to obtain
artificial puzzolan, I simply mix the salt with clay and heat or burn and
pulverize it in the ordinary manner.
Having described the nature of my Invention, and the manner in which
the same is to be carried into effect, I declare that what I claim as my
Invention is the manufacture of artificial cement, herein-before described,
obtained by the mixture of materials or matters herein-before indicated, which
when combined are submitted to a single operation of burning or calcining,
and producing the results herein-before mentioned.
In witness whereof, I, the said Charles Durand Gardissal, have hereunto
set my hand and seal, this Twenty-eighth day of March, in the year
of our Lord One thousand eight hundred and fifty-seven.
C. D. GARDISSAL. (L.S.)