Improvements in the Recovery of Ammonia in the Manufacture of Carbonate of Soda by the Ammonia Process
Year: 1885

page_text: Improvements in the Recovery of Ammonia in the Manufacture
of Carbonate of Soda by the Ammonia Process, with Pro-
We EDWARD WILLIAM PARNELL of N° 151 Bedford Street South Liverpool in
the County of Lancaster, Manufacturing Chemist, and JAMES SIMPSON of
No 8ª Rumford Place in the same City Alkali Manufacturer, do hereby declare
the nature of the said invention for "IMPROVEMENTS IN THE RECOVERY
AMMONIA IN THE MANUFACTURE OF CARBONATE OF SODA BY THE AMMONIA
PROCESS WITH PRODUCTION OF SULPHURETTED HYDROGEN to be as follows:-
"
OF
In the manufacture of carbonate of soda by the ammonia process by which we
mean the decomposition of chloride of sodium by means of ammonia and carbonic
acid a considerable expense is incurred by the employment of lime for decomposing
the resulting chloride of ammonium in order that the ammonia may be given off
in the free state for repeated use.
The objects of our invention are to dispense with the use of lime for this
purpose, and by employing alkali waste from the Le Blanc process (in which we
include drainage from the said waste) and conducting the operation in the manner
hereinafter described to recover the ammonia in the free state for repeated use-
subject only to moderate loss-and at the same time to produce sulphuretted
hydrogen in a condition available for the production of sulphur or its compounds.
In carrying our invention into operation we by preference heat a mixture of,
alkali waste and chloride of ammonium in a closed vessel to a temperature of
212° Fahr or upwards, when decomposition takes place, chloride of calcium being
formed in solution and sulphide of ammonium given off with the steam. The same
results may be obtained by agitating alkali waste and chloride of ammonium
without heat, and subsequently boiling the sulphide of ammonium so produced,
when the latter will be volatilized or carried off with the steam. The sulphide
of ammonium vapour produced by either of the foregoing operations is then
brought in contact with a solution of acid sulphate of ammonia sometimes called
Bisulphate of ammonia by any convenient means, such as by passing it through:
a tower down which the acid sulphate is caused to flow, when ordinary or neutral:
sulphate of ammonia will be formed with evolution of sulphuretted hydrogen.

page_text: We then concentrate or boil down the solution of neutral sulphate of ammonia
so produced in a suitable vessel, say of lead, and afterwards heat it in a suitable
vessel which may be of cast iron till it parts with a portion of its ammonia, say to
the extent of 30 or 40 per cent, which latter is condensed or absorbed in water and
used for the production of carbonate of soda by the well known ammonia process
while the acid sulphate of ammonia which is left behind is dissolved in water and
treated or neutralised with a further quantity of sulphide of ammonium till it is
again in the condition of ordinary or neutral sulphate of ammonia; the operation
is repeated. The sulphuretted hydrogen produced in the foregoing operation
may be employed for the manufacture of sulphur or vitriol by any of the well
known methods.
In heating the neutral sulphate in order to liberate the ammonia in the free
state care should be taken not to raise the temperature too high, say not over
800° Fahr as a loss would thereby be incurred through the decomposition. of the
ammonia by heat. In conducting this operation it is advantageous to bring
steam in contact with the sulphate of ammonia under treatment as its presence
facilitates the liberation of the ammonia and equalizes the temperature.
dave of Fahmin 100K
COMPLETE
DIEUITICATION,
We EDWARD WILLIAM PARNELL of No 151 Bedford Street South Liverpool in
the County of Lancaster Manufacturing Chemist, and JAMES SIMPSON of
No 8ª Rumford Place in the same City Alkali Manufacturer do hereby declare
the nature of the said invention for "IMPROVEMENTS IN THE RECOVERY OF
AMMONIA IN THE MANUFACTURE OF CARBONATE OF SODA BY THE AMMONIA
PROCESS WITH PRODUCTION OF SULPHURETTED HYDROGEN and in what manner
the same is to be performed, to be particularly described and ascertained in and
by the following statement :-
"
In the manufacture of carbonate of soda by the ammonia process by which we
mean the decomposition of chloride of sodium by means of ammonia and carbonic
acid a considerable expense is incurred by the employment of lime for decomposing
the resulting chloride of ammonium in order that the ammonia may be given off
in the free state for repeated use.

page_text: The objects of our invention are; to dispense with the use, or lime for the above
purpose, and by employing alkali waste from the Le Blanc process (in which we
include drainage from the said waste) and conducting the operation in the manner
hereinafter described, to recover the ammonia in the free state for repeated uso
subject only to moderate loss-and at the same time to produce sulphuretted
hydrogen in a condition available for the production of sulphur or its compounds.
In carrying our invention into operation we by preference heat a mixture of
alkali waste and solution of chloride of ammonium from the ammonia alkali
process in a closed vessel to a temperature of 212° Fah or thereabout's when
decomposition takes place, chloride of calcium being formed in solution and vapor
consisting successively of sulphuretted hydrogen, sulphide of ammonium, and
ammonia given off with steam. As these substances combine when brought in
contact forming sulphide of ammonium we refer to them as one substance namely
sulphide of ammonium for the purposes of this specification. Substantially the
same results may be obtained by agitating alkali waste and a solution of chloride
of ammonium without heat and subsequently boiling The sulphide of ammonium
so produced will be volatilized or carried off with the steam.
The sulphide of ammonium vapour produced by either of the foregoing opera-
tions in then brought in contact with a solution of acid sulphate of ammonia
sometimes called bi-sulphate of ammonia by any convenient means, such as by
passing the said sulphide through a tower down which the acid sulphate is caused
to flow. Ordinary or neutral sulphate of ammonia will be thereby formed with.
evolution of sulphuretted hydrogen.
We next concentrate or boil down the solution of neutral sulphate of ammonia
so produced in a suitable vessel say of lead, and afterwards heat the dry sulphate
of ammonia produced in a suitable vessel which may be of cast iron till it parts
with a portion of its ammonia, say to the extent of 30 or 40 per cent, which latter
is condensed or absorbed in water or brine and used for the production of carbonate
of soda by the well known ammonia process; while the acid sulphate of ammonia
which is left behind is drawn off dissolved in water and treated or neutralized
with a further quantity of sulphide of ammonium till it is again in the condition
of ordinary or neutral sulphate of ammonia: this operation may be repeated
continuously. The sulphuretted hydrogen produced in the foregoing operation
may be employed for the manufacture of sulphur or vitriol by any of the well
known methods.
In heating the neutral sulphate of ammonia in order to liberate the ammonia in
the free state care should be taken not to raise the temperature too high, say not
over 800° Fahr as a loss would thereby be incurred through the decomposition of
the ammonia by heat. In conducting this operation it is advantageous to bring
steam in contact with the sulphate of ammonia under treatment as its presence
facilitates the liberation of the ammonia and to some extent equalizes the
temperature.
A further part of our invention consists in facilitating the liberation of the
ammonia so as to obtain a larger proportion than 30 or 40 per cent given off on
heating with a very slight loss of ammonia by adding the sulphate of an alkali
which will form an acid sulphate or bi-sulphate to the sulphate of ammonia before
boiling down. For this purpose we recommend sulphate of potash. As this
alkaline sulphate serves merely to absorb the acid given off from the bi-sulphate
of ammonia on heating it is manifest that a given quantity can be used
repeatedly.
It is manifest that if a works be designed to manufacture carbonate of soda in
about equal quantities by the above process and by the Le Blanc process respec-
tively the sulphur required for the latter process may be recovered for repeated use,
or sale, by means of the chloride of ammonium of the former process while the
expense of removing the alkali waste is avoided, and an offensive nuisance will be
almost entirely obviated. By this arrangement the lime which is produced in the
kilns or retorts for supplying carbonic acid to the ammonia alkali process will be

page_text: available for the manufacture of bleaching powder or caustic soda, and if vitriol
be made from the sulphuretted hydrogen, it can either be sold on account of its
purity or employed for the manufacture of sulphate of soda and production of
hydrochloric acid.
We wish it to be understood that we do not claim the production of sulphide of
ammonium by heating alkali waste and chloride of ammonium, nor do we claim
any improvement in the manner of dealing with sulphuretted hydrogen for the
manufacture of vitriol or sulphur for which there are several well known processes,
nor do we limit ourselves to any special modification of the aminonia alkali
process.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that what
we claim is
First. The process herein described for the recovery of free ammonia and
production of sulphuretted hydrogen in connection with the ammonia alkali
manufacture, consisting in the production of sulphide of ammonium by treating
alkali waste with a solution of chloride of ammonium, the decomposition of the
said sulphide of ammonium by means of acid sulphate of ammonia with evolution
of sulphuretted hydrogen and formation of neutral sulphate of ammonia, and
heating the neutral sulphate of ammonia till it parts with a portion of the
ammonia leaving acid sulphate of ammonia available for the decomposition of a
further quantity of sulphide of ammonium.
Second. Heating neutral sulphate of ammonia obtained in the manner and
by the process herein set forth in the presence of sulphate of potash for the purpose
set forth.
Third. The above described method of combining the manufacture of carbonate
of soda by the Le Blanc process with the ammonia alkali process so as to recover
the sulphur employed in the form of sulphuretted hydrogen, prevent the accumu-
lation of noxious alkali waste and obtain increased economy by avoiding the use
of lime.