MENTS IN THE PRODUCTION OF SODA CRYSTALS IN THE MANUFACTUre of SODA BY THE AMMONIA PROCESS
Year: 1883

page_text: LETTERS PATENT to Charles Denton Abel of No 28 Southampton Buildings,
Chancery Lane in the county of Middlesex for an Invention of "IMPROVE
MENTS IN THE PRODUCTION OF SODA CRYSTALS IN THE MANUFACTUre of
SODA BY THE AMMONIA PROCESS communicated to him from abroad by "La
Societé Anonyme des Produits Chimiques de Sud Ouest, an incorporated
company, of Paris, France
"
PROVISIONAL SPECIFICATION left by the said Charles Denton Abel at the
Office of the Commissioners of Patents on the 8th August 1883.
CHARLES DENTON ABEL of No 28 Southampton Buildings, Chancery Lane, in
the County of Middlesex, " IMPROVEMENTS IN TOE PRODUCTION OF SODA
CRYSTALS IN THE MANUFACTURE OF SODA BY THE AMMONIA PROCESS," [com-
municated to him from abroad by La Societé Anonyme des Produits Chimiques
de Sud Ouest, an incorporated company, of Paris, France]
The manufacture of soda crystals includes the series of operations consisting in
the transformation of anhydrous or slightly hydrated soda into carbonate of soda
having 10 equivalents of water.
If therefore, in the manufacture of soda by the ammonia process, the bicarbonate
of soda could be transformed directly in crystals of the carbonate, the process of
calcination would on the one hand be avoided, and on the other hand, soda crystals
would be obtained direct, in an economical manner.
It is well known that, by long boiling, the bicarbonate of soda loses its second
equivalent of carbonic acid, but this operation would not be practically applicable
on account of its long duration.
It has been observed, by my correspondents, that if a mixture of water and
bicarbonate of soda in suitable proportions be prepared and if the inagnia be raised
to boiling point, the bicarbonate will, in a very short time, be transformed into
sesquicarbonate. If, at this time, a certain quantity of hot water be added, and

page_text: violent ebullition be produced, accompanied by stirring, about eighty per cent of
the excess of carbonic acid will be promptly driven off, and a solution of carbonate
of soda mixed with a slight proportion of bicarbonate produced. This is brought
by evaporation to a gravity of from 30° to 34° Beaumé, and is then allowed to cool,
whereupon soda crystals will form themselves, the bicarbonate being separated by
precipitation and used in the next operation. Before crystallisation, the last
portion of the bicarbonate can be converted by the addition of a small proportion
of lime, taking care not to employ more than exactly one equivalent of lime to the
bicarbonate.
In place of lime, sulphuric acid might be used; but this would have the objection
of introducing a certain quantity of sulphate of soda, which would injure the
quality of the crystals.
In operating with lime, the carbonate of lime formed will be rapidly precipitated,
occupying but little space in the bottom of the vat, and will not adhere to the
⚫crystals.
It is very advantageous to effect the decarbonisation in a boiler or series of boilers
subjected to a certain pressure, provided with stirring apparatus and a closed
aperture for introducing the bicarbonate.
The slightly ammoniacal vapours given off, condense in a refrigerator where
they are maintained at a temperature of about 90° Cent; at this temperature nearly
the whole of the ammonia is separated from the hot water, which serves for the
next following solution.
The separated ammonia is collected, together with the excess of steam passing.
with it, in a second refrigerator kept at-a-low temperature.
The carbonic acid gas separated as above described is drawn off by means of a
pump, being cooled in passing through the refrigerators, and is utilised in the
manufacture of soda by the ammonia process...

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Charles Denton Abel in the Patent Office on the 1st February
1884.
"
CHARLES DENTON ABEL of N° 28 Southampton Buildings Chancery Lane in
the County of Middlesex "IMPROVEMENTS IN THE PRODUCTION OF SODA
CRYSTALS IN THE MANUFACTURE OF SODA BY THE AMMONIA PROCESS A com-
munication to me from Abroad by La Societé Anonyme des Produits Chemiques
du Sud Ouest, an incorporated Company, of Paris France
The manufacture of soda crystals includes the series of operations consisting in
the transformation of anhydrous or slightly hydrated soda into carbonato of soda
having 10 equivalents of water.
If therefore, in the manufacture of soda by the ammonia process, the bicarbonate
of soda could be transformed directly into crystals of the carbonate, the process of
calcination would on the one hand be avoided, and on the other hand, soda crystals
would be obtained direct, in an economical manner.
It is well known that, by long boiling, the bicarbonate of soda loses its second
equivalent of carbonic acid, but this operation would not be practically applicablo
on account of its long duration.
It has been observed by my correspondents, that if a mixture of water and
bicarbonate of soda in suitable proportions be prepared, and if the magma be raised
to boiling point, the bicarbonate will, in a very short time, be transformed into
sesquicarbonate. If, at this time, a certain quantity of hot water be added, and
violent ebullition be produced, accompanied by stirring, about eighty per cent of
the excess of carbonic acid will be promptly driven off, and a solution of carbonato
of soda, mixed with a slight proportion of bicarbonate, will be produced. This is
brought by evaporation to a gravity of from 30° to 40° Beaumé, and is then allowed
to cool in sufficiently deep crystallising vessels. The bicarbonate is precipitated,
and good soda crystals form themselves separately. After removing the crystals,
the precipitated bicarbonate is used in succeeding operations Or, otherwise, before
crystallisation, the last portion of the bicarbonate can be decomposed by the addition
of a small proportion of lime, care being taken not to employ more than exactly
one equivalent of lime to the soda remaining in the state of bicarbonate.
In place of lime, sulphuric acid might be used; but this would have the objection
of introducing a certain quantity of sulphate of soda, which would injure the
quality of the crystals.
In operating with lime, the carbonate of lime formed is rapidly precipitated,
occupying but little space in the bottom of the vessel, and not adhering to the
crystals.
It is very advantageous to effect the decarbonisation in a boiler or series of
connected boilers subjected to a certain degree of exhaustion, these being provided
with stirring apparatus and having apertures, for introducing the bicarbonate,
which can be tightly closed.
The slightly ammoniacal vapors given off, condense in a cooler, where they are
maintained at a temperature of about 90° Cent.; at this temperature, nearly the
whole of the ammonia is separated from the hot water of condensation, which serves
for the next following solution.
The separated ammonia is collected together with the excess of steam passing
with it, in a second refrigerator kept at a low temperature.
-
The carbonic acid gas separated from the bicarbonate by ebullition is drawn off
by means of a pump, being cooled in passing through the refrigerators, and is
utilised in the manufacture of soda by the ammonia process.

page_text: Having thus described the nature of this invention, and in what manner the same
is to be performed, as communicated to me by my foreign correspondents,
I claim-
In the manufacture of soda by the ammonia method, the herein described process
for directly producing soda crystals, whereby the carbonic acid driven off by
ebullition is utilised, and the ammonia is recovered.
In Witness whereof I the said Charles Denton Abel have hereunto set my hand
and seal this First day of February in the year of our Lord One thousand eight
hundred and eighty-four