the Ammonia Soda Process, and Recovery of Ammonia and . Carbonic Acid, and Apparatus Employed therefor.
Year: 1885

page_text: the Ammonia Soda Process, and Recovery of Ammonia and
. Carbonic Acid, and Apparatus Employed therefor.
I FREDERICK JOHN PICKERING CHEESBROUGH, of 15, Water Street, Liverpool, in
the County of Lancaster, Consulting Engineer and Patent Agent do hereby declare
the nature of the said Invention for AN IMPROVED METHOD OF MANUFACTURING
SODA CRYSTALS, AND CAUSTIC SODA DIRECT FROM THE BICARBONATE RESULTING
FROM THE AMMONIA SODA PROCESS, AND RECOVERY OF AMMONIA AND CARBONIC
ACID, AND APPARATUS EMPLOYED THEREFOR to be as follows:
The bicarbonate obtained as an intermediate product by what is known as the
Ammonia Soda process has not previous to this invention been suitable to be
worked up by direct means into soda crystals, or caustic soda. The process
employed hitherto has been to convert the bicarbonate into monocarbonate or soda
ash by calcination and from this soda ash dissolved in water to manufacture soda
crystals or caustic soda.
The direct use of bicarbonate for the production of full strength crystal, or
caustic liquor has been prevented hitherto by the difficulty of decomposing
bicarbonate by boiling in a watery solution, more particularly if high strength
soda liquor suitable for direct crystallization was required.
In such liquor there may be about 60% of bicarbonate undecomposed which
even by long boiling cannot be transferred into monocarbonate of soda. Such
liquors are naturally unsuitable for the production of soda crystals or caustic soda.
According to this present invention and for the purpose of immediately obtaining
strong crystallizable soda liquor, the bicarbonate obtained by the ammonia soda
process, mixed with the proper quantity of water, is heated to boiling point under
atmospheric pressure, either by steam or by an open fire, in the apparatus herein-
after described and herein termed the decomposer. The liquor is retained at
boiling point until its partial decomposition to monocarbonate takes place, which

page_text: under the best circumstances reaches 40%. For the complete decomposition of
the remaining 60% of bicarbonate contained in the liquor into monocarbonate, an
increased pressure of steam is employed, which pressure may be raised to 60 lbs on
the square inch, and under this pressure the decomposition is exceedingly rapid.
A strong agitation of the soda liquor under pressure is kept up in the apparatus,
which agitation has a very marked influence on the entire expulsion of the carbonic
acid contained in the liquor, and quickly causes the desired decomposition.
The crystal liquor obtained in this way is generally of a greenish colour, arising
from tarry matter and cannot be removed by the customary application of a
solution of bleaching powder. The crystals obtained by this means are of a pink
colour becoming brown on exposure to the air.
In order to overcome the above objection, and according to this invention, there
is used such oxydizing agents as free chlorine, or a solution of chlorine in water,
whereby the tar pigments are entirely destroyed and a clear liquor yielding white
crystals is obtained.
At
The apparatus according to this invention used in carrying out the above
described method, consists of a wrought or cast iron cylindrical vessel, the bottom of
which is formed conically at an angle of 45°. On the side of this vessel or boiler
there is provided a charging opening fitted with a suitable tight closing cover.
the bottom of the vessel there are provisions for carrying a steam distributor which
consists of a cast iron bell the edge of which is serrated to facilitate the even
distribution of steam, which is supplied under the bell from a steam pipe.
The vessel is fitted with suitable sampling cocks, and a blow off pipe for the
soda liquor.
The vessel is provided with a central shaft which runs in a footstep on the top
of the steam distributor, the other end of the shaft passing through a stuffing box.
This shaft carries an agitating apparatus, which cousists of an open cylinder flared
at both ends, on the outside of which there is a spiral blade with a right hand
pitch and on the inside of which there is a spiral blade with a left hand pitch.
The object of these blades is to drive the liquid upwards by means of the outward
blade or worm and by means of the inward blade or worm to force the liquid
violently back to the bottom of the vessel. By this means a perfect mixture and
agitation of the liquid takes place.
The carbonic acid, ammonia and surplus steam are led by a pipe to a condensing
apparatus where the ammonia is obtained in solution, and the carbonic acid passed
on for further use.
The liquor may be causticized in the same apparatus, which is provided with an
opening for the introduction of the necessary lime.

page_text: the Ammonia Soda Process, and Recovery. of Ammonia and
Carbonic Acid, and Apparatus Employed therefor..
I FREDERICK JOHN PICKERING CHEESBROUGH of 15 Water Street, Liverpool in
the County of Lancaster, Consulting Engineer and Patent Agent do hereby declare
the nature of the said Invention for AN IMPROVED METHOD OF MANUFACTURING
SODA CRYSTALS AND CAUSTIC SODA DIRECT FROM THE BICARBONATE RESULTING
FROM THE AMMONIA SODA PROCESS, AND RECOVERY OF AMMONIA AND CARBONIC
ACID AND APPARATUS EMPLOYED THEREFOR and in what manner the same is to
be performed, to be particularly described and ascertained in and by the following
statement:-
The bicarbonate obtained as an intermediate product by what is known as the
Ammonia Soda process has not previous to this Invention been suitable for
working up by direct means into soda crystals, or caustic soda. The process
employed hitherto has been to convert the bicarbonate into monocarbonate, or
soda ash, by calcination and from this soda ash dissolved in water to manufacture
soda crystals, or caustic soda.
The direct use of bicarbonate for the production of full strength crystal or
caustic liquor has been prevented hitherto by the difficulty of decomposing
bicarbonate by boiling in a watery solution,. more particularly if high strength
soda liquor suitable for direct crystallization was required.
In such liquor there may be about 60% of bicarbonate undecomposed which
even by long boiling cannot be transferred into monocarbonate of soda. Such
liquors are naturally unsuitable for the production of soda crystals, or caustic sorla.
According to this present Invention and for the purpose of immediately obtaining
strong crystallizable soda liquor, the bicarbonate obtained by the ammonia soda
process mixed with the proper quantity of water is heated to boiling point under
atmospheric pressure either by steam, or by an open fire, in the apparatus herein-
after described and herein termed the decomposer. The liquor is retained at boiling
point until its partial decomposition to monocarbonate takes place which under
the best circumstances reaches 40%. For the complete decomposition of the
remaining 60% of bicarbonate contained in the liquor into monocarbonate an
increased pressure of steam is employed, which pressure may be raised to say
60 lbs on the square inch and under this pressure the decomposition is exceedingly
rapid.
A strong agitation of the soda liquor under pressure is kept up in. the apparatus,
which agitation has a very marked influence on the entire expulsion of the carbonic
acid contained in the liquor and quickly causes the desired decomposition.
The crystal liquor obtained in this way is generally of a greenish colour,.arising
from tarry matter-and cannot be removed by the customary application of a
solution of bleaching powder. The crystals obtained by this means are of a pink
colour becoming.brown on exposure to the air,

page_text: In order to overcome the above objection there is used such oxydizing agents as
free chlorine, or a solution of chlorine in water, whereby the tar pigments are
entirely destroyed and a clear liquor yielding white crystals is obtained.
I will now describe the apparatus according to this Invention used in carrying
out the above described method, reference being had to the annexed sheet of
Drawings in which
Figure 1 is a sectional elevation of the apparatus used for heating the liquor
and for condensing the gases and steam and obtaining the ammonia and carbonic
acid.
Figure 2 is a vertical section of the agitating device used in connection with
Figure 1.
The apparatus consists of a wrought, or cast iron cylindrical vessel A, the bottom
of which is preferably of conical form. On one side of this vessel, or boiler A
there is provided a charging opening B having a mouthpiece and a tight closing
cover B¹. The vessel, or boiler A is supported on brackets D. At the bottom
inside the vessel, or boiler A there are three brackets, or provisions C which
support and carry a steam distributor E which consists of a cast iron bell, the
lower edge of which is serrated to facilitate the even distribution of steam which
is supplied through the steam pipe H which passes in through the bottom of the
vessel A and under the bell E The pipe H is provided with a steam regulating
valve H. The vessel A is fitted with suitable sampling cocks G¹ G' G³ and with
a manhole door I, and with a blow off pipe at F for discharging the soda liquor.
The vessel A is provided with a central shaft P which runs in a footstep a on the
top of the steam distributor E. The other end of the shaft P passes through a
stuffing box b on the top of the vessel A and is provided with a pulley d by which
the shaft P is rotated by means of a belt, or band. On the shaft P there is fitted
an agitating device J which is shown to a larger scale in vertical section at
Figure 2. This agitating device J consists of a cylinder open and flared at both
ends. Outside this cylinder there is a spiral blade e having a right hand pitch,
and inside the cylinder there is a spiral blade f having a left hand pitch. The
object of these blades e and fis to drive the liquid in the vessel A upwards by
means of the outside blade, or worm e and to force the liquid violently back to the
bottom of the vessel A by means of the spiral blade, or worm f, so that by this
means a most perfect mixture and agitation of the liquid in the vessel A takes
place.
The carbonic acid, ammonia and surplus steam are led from the vessel A through
the chest K and pipe L to a surface condensing apparatus M where the ammonia is
obtained in solution and the carbonic acid is passed on for further use.
The con-
densing apparatus A is an ordinary tubular surface condenser provided with the
usual inlets and outlets for the steam and gases to be condensed and for the service
of the condensing water.
The liquor in the vessel A may be causticized by the introduction of the necessary
lime which can be supplied to the vessel A through an opening N which is provided
for this purpose.
In operation the vessel A is charged through the opening B with bicarbonate
obtained by the ammonia soda process mixed with the proper quantity of water
and this, liquor is boiled by the application of steam through the pipe H and
agitated during treatment as herein before described.
In the apparatus shown in the Drawings the liquor in the vessel A is heated by
steam, but the same result can be obtained by heating the vessel by a furnace,
or fire.
.
Having now particularly described and ascertained the nature of the said
Invention and in what manner the same is to be performed I declare that what
I claim is
First. The method substantially as herein described. of manufacturing soda
crystals and caustic soda direct from the bicarbonate resulting from the ammonia

page_text: soda process and the recovery of ammonia and carbonic acid therefrom, which
method consists in decomposing the bicarbonate resulting from the ammonia soda
process by heat in a closed vessel under pressure and agitating the liquor as
herein described, until such liquor is suitable for direct crystallization, or for the
manufacture of caustic soda, as set forth.
Second. Effecting the decomposition of the bicarbonate resulting from the
ammonia soda process by heat in a closed vessel under pressure until such liquor
is suitable for direct crystallization, or for the manufacture of caustic soda, sub-
stantially as set forth.
Third. Effecting the decomposition of the bicarbonate resulting from the
ammonia soda process by heat in a closed vessel under pressure and agitating the
liquor until such liquor is suitable for direct crystallization, or for the manufacture
of caustic soda, substantially as set forth.
Fourth. The construction and arrangement of parts of the apparatus sub-
stantially as herein described and shown in the Drawings for manufacturing soda
crystals and caustic soda direct from the bicarbonate resulting from the ammonia
soda process and the recovery of ammonia as set forth.
Fifth. In connection with an apparatus such as herein described for manu-
facting soda crystals and caustic soda, the use of an agitator such as J whereby
an upward and downward movement is imparted to the liquid substantially as set
forth.
Sixth. The construction and form of the agitator J substantially as herein
described and shown in the Drawings hereto annexed.
Dated this fifth day of May 1886.
FREDERICK JOHN PICKERING CHEESBROUGH.
By Cheesbrough & Royston,
Agents.