IMPROVEMENTS IN THE MANUFACTURE
Year: 1881

page_text: LETTERS PATENT to Ernest Solvay, of Brussels, in the Kingdom of Belgium,
Manufacturer, for an Invention of IMPROVEMENTS IN THE MANUFACTURE
"
65
PROVISIONAL SPECIFICATION left by the said Ernest Solvay at the Office
of the Commissioners of Patents on the 14th May 1881.
ERNEST SOLVAY, of Brussels, in the Kingdom of Belgium, Manufacturer.
"IMPROVEMENTS IN THE MANUFACTURE OF SODA."
This Invention relates to the manufacture of soda by the process generally
known as the ammonia process, for which Letters Patent were granted to me bearing
date the 11th of December 1863, No. 3131; the 18th of May 1872, No. 1515;
the 8th of March 1876, No. 999; the 5th of May 1876, No. 1904; the 20th of May
1876, No. 2143; and the 16th of June 1879, No. 2387.
In the manufacture of soda by the ammonia process (whether ordinary ammonia
or compound ammonia be used in the said process), it is now well known that
great difficulty is experienced in effecting the decomposition or calcination of the
bicarbonate of soda obtained. Its tendency to become pasty, and also its being a
bad conductor of heat, are the reasons why many calcining apparatus do not
decompose the bicarbonate of soda as they should, or do not decompose the amount
of bicarbonate they should decompose.
By mixing a portion of calcined soda with the bi-carbonate before effecting the
decomposition of the said bicarbonate, as described in the Provisional Specification
filed by me on the 9th of May 1881, I have been able to overcome the first of
these difficulties. As regards the second difficulty, which is due to the material
being a bad conductor of heat, I overcome it by bringing the bicarbonate of soda
into such intimate contact with the heating medium that it may be said to be in
molecular contact with it.
For this purpose I violently agitate the bicarbonate of soda so as to reduce it to
dust or powder, and to cause it to be constantly projected in every direction within
the decomposing apparatus, the outer surface or sides of which are heated exteriorly
cither by furnaces or by high pressure steam or otherwise. By this means not

page_text: only the contact of the bicarbonate of soda with the heated sides of the apparatus
is constantly renewed, but the contact of the gas and steam which constitute the
internal atmosphere of the said apparatus, and in which the powdered bicarbonate
of soda is held as it were in suspension, is also constantly renewed with the same
sides, and transmit their heat in every direction, and even to the centre of the
apparatus.
On the other hand the agitation above described causes the material (bicarbonate
of soda) to move forward in a contrary direction to that of its introduction even in
horizontal apparatus.
I prefer to give to the apparatus a cylindrical form, but any other suitable form
may be adopted. The said apparatus consists either of a long cylindrical tube
provided internally with a rotatory agitator running along the whole length of it, or
several cylindrical tubes may be used, either one above the other or placed side by
side, and communicating one with the other at their ends, so that the length
of one is added to the length of the others, as will be well understood by
manufacturers.
The gases and vapours produced, and which are given off in the usual manner,
carry away with them a portion of the powdered bicarbonate of soda. I free them
from the said bicarbonate by causing them to pass by any suitable known means
into a large sized reservoir where the bicarbonate is allowed to settle, and from
whence it may be removed from time to time, either to be returned to the
decomposing apparatus or for any other purpose.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Ernest Solvay in the Great Seal Patent Office on the 1st November
1881.
ERNEST SOLVAY, of Brussels, in the Kingdom of Belgium, Manufacturer.
"IMPROVEMENTS IN THE MANUFACTURE OF SODA."
This Invention relates to the manufacture of soda by the process generally
known as the ammonia process, for which Letters Patent were granted to me
bearing date the 11th of December 1863, No. 3131; the 18th of May 1872,
No. 1515; the 8th of March 1876, No. 999; the 5th of May 1876, No. 1904; the
20th of May 1876, No. 2143; and the 16th of June 1879, No. 2387.
In the manufacture of soda by the ammonia process (whether ordinary ammonia
or compound ammonia be used in the said process), it is now well known that
great difficulty is experienced in effecting the decomposition or calcination of tho
bicarbonate of soda obtained.
Its tendency to become pasty and also its being a bad conductor of heat are the
reasons why many calcining apparatus do not decompose the bicarbonate of soda
as they should, or do not decompose the amount of bicarbonate they should
decompose.
By mixing a portion of calcined soda with the bicarbonate before effecting the
decomposition of the said bicarbonate, as described in the Specification of Letters
Patent granted to me bearing date the 9th of May 1881, No. 2017, I have been
able to overcome the first of these difficulties. As regards the second difficulty,
which is due to the material being a bad conductor of heat, I overcome it by
bringing the bicarbonate of soda into such intimate contact with the heating
medium that it may be said to be in molecular contact with it. For this purpose
I violently agitate the bicarbonate of soda so as to reduce it to dust or powder,
and to cause it to be constantly projected in every direction within the decomposing
apparatus, the outer surface or sides of which are heated exteriorly either by
furnaces or by high pressure steam or otherwise. By this means not only the
contact of the bicarbonate of soda with the heated sides of the apparatus is con-
stantly renewed, but the contact of the gas and steam which constitute the internal
atmosphere of the said apparatus, and in which the powdered bicarbonate of soda
is held as it were in suspension, is also constantly renewed with the same sides, and
transmit their heat in every direction, and even to the centre of the apparatus.
On the other hand the agitation above described causes the material (bicarbonate
of soda) to move forward in the contrary direction to that of its introduction even
in horizontal apparatus.
I prefer to give to the apparatus a cylindrical form, but any other suitable form
may be adopted. The said apparatus consists either of a long cylindrical tube
provided internally with a rotatory agitator running along the whole length of it,
or several cylindrical tubes may be used either one above the other or placed side by
side, and communicating one with the other at their ends, so that the length of one is
added to the lengths of the others, as will be well understood by manufacturers.
The gases and vapours produced and which are given off in the usual manner carry
away with them a portion of the powdered bicarbonate of soda. I free them from
the said bicarbonate by causing them to pass by any suitable known means into a
large sized reservoir where the bicarbonate is allowed to settle, and from whence
it may be removed from time to time, either to be returned to the decomposing
apparatus, or for any other purpose.
Having now described the nature of my said Invention, and the manner of
performing the same, I claim as my Invention,-
1. In the manufacture of ammonia soda, the process of violently agitating the

page_text: bicarbonate of soda in the decomposing or calcining apparatus heated exteriorly,
substantially as and for the purposes described.
2. The apparatus hereinbefore described for violently agitating and decomposing
or calcining bicarbonate of soda in the manufacture of ammonia soda, that is to say,
a long tube or several tubes placed one above the other or side by side, such tube
or tubes being heated externally and armed internally with a rotatory agitator or
rotatory agitators which violently agitate the bicarbonate of soda within the said
tube or tubes, reducing the said bicarbonate to powder or dust, and projecting it
against the sides of the said tube or tubes, thus bringing it into intimate contact
with the gases and vapours which effect the decomposition or calcination of the
Baid bicarbonate, substantially a hereinbefore described and for the purposes set
forth.
In witness whereof, I, the said Ernest Solvay, have hereunto set my hand
and seal, this Twenty seventh day of October, in the year of our Lord One
thousand eight hundred and eighty one.
ERNEST SOLVAY. (L.S.)