IMPROVE- MENTS IN THE MANUFACTURE OF CARBONATES OF SODA.”
Year: 1874

page_text: LETTERS PATENT to Ludwig Mond, of Northwich, in the County of
Chester, Manufacturing Chemist, for the Invention of "IMPROVE-
MENTS IN THE MANUFACTURE OF CARBONATES OF SODA.”
MENTS IN THE MANUFACTURE OF CARBONATES OF SODA.”
PROVISIONAL SPECIFICATION left by the said Ludwig Mond at
the Office of the Commissioners of Patents, with his Petition, on
the 4th December 1874.
I, LUDWIG MOND, of Northwich, in the County of Chester, Manu-
facturing Chemist, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN THE Manufacture of CarBONATES OF SODA,” to be as
follows:
-
"
My Invention relates to that process in the commercial production of
carbonates of soda which is known as the direct process by ammonia, and
has for its object the production in a more regular manner of a purer
article than that which is now frequently obtained, for which purpose I
submit the brine in the first instance to a purifying treatment. This

page_text: I propose to effect by adding thereto an alkali, which may be caustic,
or a carbonate, or a mixture of the two, but the method I prefer is to
add a combination of alkali and lime, and in such proportions as may
be found necessary by experience, according to the nature of the brine.
to be treated. When this has been done I settle or filter off the
precipitate produced, and then use the brine in the aforesaid known
process.
•
Secondly. I conduct the operations by the aforesaid direct process of
ammonia, but so as to ensure the presence of sulphur in the ammoniacal
brine employed in this process, which substance I have found to have a
material effect upon the quality of the desired products. For this
purpose I propose to add to the ammoniacal brine an alkaline sulphide,
or to pass sulphuretted hydrogen, or the vapour of sulphide of ammonia,
into the said solution, but as a convenient form I propose to use the
waste liquor arising from the manufacture of illuminating gas.
Proportions cannot be given, as they will necessarily vary, but the
proper quantities may be readily ascertained by experience.
Another part of my Invention consists in obtaining a denser product
than has hitherto been produced. For this purpose I take the carbonate
of soda produced by aid of my improvement aforesaid, or by the usual,
means, and place it in a reverberatory or other such furnace, and
continue the heat until the mass, has become reduced to a pasty con-
sistency, by which treatment the bulk of the product is greatly reduced,
and this makes it more suitable for commercial uses, and also effects a
saving in package. Or the bicarbonate may be placed direct in a
reverberatory furnace, the operation then commencing at a low heat
until the conversion into the monocarbonate has taken place, and then
increasing the heat until the above described result has been obtained.

page_text: WHEREAS Her most Gracious Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fourth day of December, in the
year of our Lord One thousand eight hundred and seventy-four, in
the thirty-eighth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Ludwig Mond, Her special
license that I, the said Ludwig Mond, my executors, administrators,
and assigns, or such others as I, the said Ludwig Mond, 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 and lawfully might make, usc, exercise,
and vend, within the United Kingdom of Great Britain and Ireland,
the Ohannel Islands, and Isle of Man, an Invention for "IMPROVEMENTS
IN THE MANUFACTURE OF CARBONATES OF SODA," upon the condition, amongst
others, that I, the said Ludwig Mond, by an instrument in writing
under my hand and seal, 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 within six calendar months next and immediately after the date
of the said Letters Patent.
NOW KNOW YE, that I, the said Ludwig Mond, do hereby declare
the nature of my said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by
the following statement, that is to say :-
My Invention relates to that process for the commercial production of
carbonates of soda which is known as the direct process by ammonia,
and in which brine as derived from natural sources is used; and my
Invention has for its object the production in a more regular manner of
a purer article than that which is now frequently obtained. For this
purpose
I submit the brine in the first instance to a purifying treatment.
To effect this I add to the said brine an alkali, which may be caustic, or
a carbonate, or a mixture of the two, but the method I prefer is to add
a mixture of alkali (soda ash by preference) and lime. The proportions
of these two substances may be varied, and the bulk added to a given
quantity of brine also varied according to the nature of the brine to be
treated, and the amount of such variations will readily be found by
experience, but usually a small quantity only will be required, say, for
instance, eighty pounds of soda ash and twenty pounds of lime for every
one thousand gallons of brine. When this has been done a precipitate

page_text: takes place, which I settle or filter off, and the clarified brine is then
sed in the well-known manner for producing carbonates of soda by tho
aforesaid direct process by ammonia.
Secondly. In the production of carbonates of soda by the aforesaid
direct process of ammonia I so operate as to cause the presence of a 5
sulphide or sulphides in the ammoniacal brinc therein employed, which
substances I have found to have a material effect upon the quality of the
required products. To ensure this presence of a sulphide, and in
sufficicnt quantity, I add to the ammoniacal brine an alkaline sulphide,
such as sulphide of ammonium, or I pass sulphuretted hydrogen or the 1
vapour of sulphide of ammonium into the said solution, but as a con-
venient and economical form I use the waste liquor arising from the
manufacture of illuminating gas, and the manner in which I prefer to
do this is to distil the said gas liquor and to allow the resulting vapours
of ammonia and sulphido of ammonium to pass into the ammoniacal 1
brine.
The quantities of these substances will necessarily vary according to
their own qualitics, and according to that of the ammoniacal brinc, but
they will readily be ascertained by experience, but usually a very small
quantity of sulphide only is required, the result when the process is a
properly conducted being the production of carbonates of great purity,
especially free from iron, inasmuch as the corrosion of the iron vessels
used in the manufacture and which usually takes place is prevented.
•
Another part of my Invention consists in obtaining a denser product
than has hitherto been produced. For this purpose I take the carbonate a
of soda produced by the aforesaid direct action process by ammonia and
place it in a reverberatory or other such furnace, and continue the heat
until the mass has become reduced to a pasty consistency. By these
means the bulk is greatly reduced, and this makes it more suitable for
commercial uses, and also effects a saving in package.
The process may be varied by placing the bicarbonate obtained by the
aforesaid process direct into a reverberatory furnace and commencing
the operation at a low red heat until the conversion into monocarbonate
is effected, and then increasing the heat until the above described result
has been obtained.

page_text: to be understood that I claim as secured to me under the above in part
recited Letters Patent, and for the purposes above set forth,—
Firstly. Purifying the raw brine by submitting it to the action of an
alkali, or an alkali and lime.
Secondly. Securing the presence of a sulphide or sulphides in the
ammoniacal brine used in the aforesaid process.
Thirdly. Submitting carbonate of soda as produced by the aforesaid
process to the action of heat in a reverberatory or other such furnace.
In witness whereof, I, the said Ludwig Mond, have hereunto set
my hand and seal, this Second day of June, in the year of
our Lord One thousand eight hundred and seventy-five.