AN IMPROVED PROCESS AND APPARATUS FOR THE RECOVERY OF BI-CARBONATE OF AMMONIA FROM THE LIQUORS PRODUCED IN THE AMMONIA PROCESS FOR MANUFACTURE OF SODA."
Year: 1880

page_text: <5
THE
ETTERS PATENT to John Imray, of No. 28, Southampton Buildings, Chancery
Lane, in the County of Middlesex, for an Invention of AN IMPROVED
PROCESS AND APPARATUS FOR THE RECOVERY OF BI-CARBONATE OF AMMONIA
FROM THE LIQUORS PRODUCED IN THE AMMONIA PROCESS FOR
MANUFACTURE OF SODA." A communication from abroad by Camille Alfred
de la Martellière, President of La Société Anonyme des Produits Chimiques
du Sud-Ouest, of Paris, France.
PROVISIONAL SPECIFICATION left by the said John Imray at the Office of
the Commissioners of Patents on the 9th August 1880.
JOHN IMRAY, of No. 28, Southampton Buildings, Chancery Lane, in the County
of Middlesex. "AN IMPROVED PROCESS AND APPARATUS FOR THE RECOVERY
OF BI-CARBONATE OF AMMONIA FROM THE LIQUORS PRODUCED IN THE AMMONIA
PROCESS FOR THE MANUFACTURE OF SODA." [A communication from abroad by
Camille Alfred de la Martellière, President of La Société Anonyme des Produits
Chimiques du Sud-Ouest, of Paris, France.]
In the manufacture of soda by the ammonia process the hydrochlorate of
ammonia liquors, which contain a certain amount of bicarbonate of soda, and also
a little undecomposed sodium chloride and bicarbonate of ammonia, are usually
mixed with lime and distilled so as to eliminate the ammonia, which is converted
into bicarbonate by a current of carbonic anhydride produced by calcination of
limestone. As in this process large quantities of lime have to be prepared attempts
have been made to employ carbonate of lime to act directly on the liquors without
first calcining it. This Invention relates to a process and apparatus for treating
the liquors above mentioned, so as to obtain from them the bicarbonate of
ammonia in a simple and economical manner. For this purpose the hydrochlorate
of ammonia liquors are heated for some time in a boiler, so as to drive off the
free bicarbonate of ammonia which is carefully collected. The liquors are then
run off into evaporating vessels, and are slowly concentrated until the sal-ammoniac
is precipitated. The evaporating vessels may be of iron coated with lead by means
D

page_text: of the double chloride of lead and ammonium, as described in the Specification to
the Patent granted to me on the 29th October 1878, No. 4353. The precipitated
sal-ammoniac is allowed to drain for a time (the mother liquor being returned to
the boiler), and it is made into a paste with powdered carbonate of lime or
dolomite, and the mixture is charged into narrow retorts and slowly heated.
Towards the end of this operation, which corresponds with that employed in the
manufacture of sesqui-carbonate of ammonia, a little milk of lime is introduced
into the retorts so as to decompose the last traces of sal-ammoniac. The fumes
proceeding from the distillation are condensed in a special apparatus of the
following description:-In an open water tank of moderate depth are immersed
mouth downwards a number of rectangular vessels or condensers open at the
bottom, and having a number of partitions projecting down into the water of the
tank. The fumes from a retort (which consist chiefly of ammonia mixed with
sesqui-carbonate) along with carbonic anhydride resulting from the calcination of
limestone, or otherwise produced, are led by large pipes into the first compartment
of a condenser, and bubble up through the water as they pass under the successive
partitions, combining to form bi-carbonate of ammonia in the liquid of the tank.
The bicarbonate sinking to the bottom is drawn by a rake into a receptacle below
the tank, from which it is from time to time withdrawn by a manhole. The rake
is fitted to travel along the bottom of the tank under the partitions of the
condensers, and it is worked by a rod passing through stuffing boxes in the ends
of the condensers and tank. The passage to the receptacle for the bicarbonate is
furnished with a valve by which it can be closed when the manhole is to be opened
for discharging the receptacle.

page_text: DIECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Imray in the Great Seal Patent Office on the 5th November
1880.
JOHN IMRAY, of No. 28, Southampton Buildings, Chancery Lane, in the County
of Middlesex. AN IMPROVED PROCESS AND APPARATUS FOR THE RECOVERY
OF BI-CARBONATE OF AMMONIA FROM THE LIQUORS PRODUCED IN THE AMMONIA
PROCESS FOR THE MANUFACTURE OF SODA." A communication from abroad by
Camille Alfred de la Martellière, President of La Société Anonyme des Produits
Chimiques du Sud-Ouest, of Paris, France.
In the manufacture of soda by the ammonia process the hydrochlorate of
ammonia liquors, which contain a certain amount of bi-carbonate of soda, and also
a little undecomposed sodium chloride and bi-carbonate of ammonia, are usually
mixed with lime and distilled so as to eliminate the ammonia, which is converted
into bi-carbonate by a current of carbonic anhydride produced by calcination of
limestone. As in this process large quantities of lime have to be prepared attempts
have been made to employ carbonate of lime to act directly on the liquors without
first calcining it. This Invention relates to a process and apparatus for treating
the liquors above mentioned, so as to obtain from them the bi-carbonate of ammonia
in a simple and economical manner. For this purpose the hydrochlorate of
ammonia liquors are heated for some time in a boiler, so as to drive off the free
bi-carbonate of ammonia which is carefully collected. The liquors are then run off
into evaporating vessels, and are slowly concentrated until the sal-ammoniac is
precipitated. The evaporating vessels may be of iron coated with lead by means
of the double chloride of lead and ammonium, as described in the Specification to
the Patent granted to me on the 29th October 1878, No. 4353. The precipitated
sal-ammoniac is allowed to drain for a time (the mother liquor being returned to
the boiler), and it is made into a paste with powdered carbonate of lime or
dolomite, and the mixture is charged into narrow retorts and slowly heated.
Towards the end of this operation, which corresponds with that employed in the
manufacture of sesqui-carbonate of ammonia, a little milk of lime is introduced into
the retorts so as to decompose the last traces of sal-ammoniac. The fumes
proceeding from the distillation are condensed in a special apparatus of the following
description: In an open water tank of moderate depth are immersed mouth
downwards a number of rectangular vessels or condensers open at the bottom, and
having a number of partitions projecting down into the water of the tank. The
fumes from a retort (which consist chiefly of ammonia mixed with sesqui-carbonate)
along with carbonic anhydride resulting from the calcination of limestone, or
otherwise produced, are led by large pipes into the first compartment of a condenser,
and bubble up through the water as they pass under the successive partitions,
combining to form bi-carbonate of ammonia in the liquid of the tank. The
bicarbonate sinking to the bottom is drawn by a rake into a receptacle below the
tank, from which it is from time to time withdrawn by a manhole. The rake is
fitted to travel along the bottom of the tank under the partitions of the condensers,
and it is worked by a rod passing through stuffing boxes in the ends of the
condensers and tank. The passage to the receptacle for the bi-carbonate is furnished
with a valve by which it can be closed when the manhole is to be opened for
discharging the receptacle.
The accompanying Drawings shew the construction and arrangement of the
condenser referred to above; Fig. 1 is a transverse, Fig. 2 a longitudinal section,
and Fig. 3 a plan. It consists of a number of shallow rectangular vessels A
immersed in a tank B through which cold water circulates. In the vessels A
there are a number of partitions a, a, extending about half way down, so that
their lower edges being immersed in the liquid, the fumes and gas introduced into

page_text: the first compartment by the pipes C, C¹, are caused to bubble from compartment
to compartment, becoming absorbed on their way. Near the end is the receptacle D,
into which the solid precipitate is raked by the rake E, and which from time to
time is emptied by opening the manhole b. The rod of the rake E passes through
stuffing boxes c, c. The opening to the receptacle D is fitted with a valve d which
can be closed for the purpose of emptying D while the apparatus continues in
action.
Having thus described the nature of the said Invention and in what manner the
same is to be performed, as communicated to me by my foreign correspondent, I
claim in respect of treatment of the liquors resulting from the ammonia process for
the manufacture of soda,-
First. The herein described process for recovering bi-carbonate of ammonia, that
process consisting of the following successive stages of operation :-Driving off
from the liquor by heat and collecting the free bi-carbonate; concentrating the
residuary liquor till the sal-ammoniac is precipitated in vessels coated as described;
mixing the drained precipitate to a paste with powdered carbonate of lime or
dolomite; heating the paste in retorts with addition of milk of lime; mixing the
fumes with carbonic anhydride and condensing the mixture.
Second. The use in the last stage of the process above referred to of condensing
apparatus, constructed and arranged substantially as herein described with reference
to the accompanying Drawings.
In witness whereof, I, the said John Imray, have hereunto set my hand
and seal, this Fifth day of November, in the year of our Lord One
thousand eight hundred and eighty.