An Improved Process of Manufacturing Soda by Means of Ammonia, and Producing Carbonate of Soda, Caustic Soda, and Hydro- chloric Acid or Chlorine.
Year: 1888

page_text: PROVISIONAL SPECIFICATION.
An Improved Process of Manufacturing Soda by Means of Ammonia,
and Producing Carbonate of Soda, Caustic Soda, and Hydro-
chloric Acid or Chlorine.
I, ALEXANDER MELVILLE CLARK, of the firm of A. M. and Wm. Clark, of 53,
Chancery Lane, in the County of Middlesox, Fellow of the Institute of Patent
Agents, do hereby declare the nature of this invention (a communication to
me from abroad by Jean Baptiste Daguin, of 44, Rue de Château Landon, Paris,
France, Manufacturer of Chemical Products) to be as follows:-
This Invention relates to an improved process for the manufacture of soda by
means of ammonia and the parallel and simultaneous production of sodium carbonate,
caustic soda, hydrochloric acid, and chlorine.
Before describing the invention, I will first briefly refer to the principal reactions
which form the basis of the ammonia-soda process as now practised :-
:-
(a) A solution of sodium chloride containing a suitable proportion of ammonia is
treated with carbonic acid forming bicarbonate of soda which precipitates and
ammonium chloride which remains in solution in the mother water :-
Na Cl+Az H' O +
HO=
Az HCl + Na O, HO, 2 CO²
(b) The bicarbonate of soda precipitate is collected on a filter and on being calcined
produces sodium carbonato setting free the carbonic acid employed in the first
reaction:-
[Price 8d.]
Na O, HO, 2 CO³ = Na O, CO* + HO + CO.
A

page_text: (c) The filtered liquid containing ammonium chloride is treated with lime and
boiled thus liberating the ammonia, which serves for a fresh decomposition of sodium
chloride according to the first reaction, calcium chloride being formed.
chloride according to the first reaction, calcium chloride being formed.
Az H' Cl + Ca 0 = Az H³ 0 + Ca Cl.
The Lime is obtained by calcining limestone the carbonic acid which disengages
in this decomposition being utilized for the first reaction.
The great objection to the above process is that calcium chloride is produced a
product which is unutilizable and which entails the loss of the whole of the chlorine of
the chloride of sodium..
I am aware that it has been proposed to employ magnesia in lieu of lime for the
regeneration of the ammonium chloride whereby magnesium chloride is obtained
which is decomposed at a red heat by oxygen or steam forming hydrochloric acid or
chlorine, the magnesia being regenerated. This process however is difficult of appli-
cation to the ammonia process as it would entail the production of such weak solutions
of magnesium chloride as to render their concentration very costly.
The process hereinafter described enables chlorine, hydrochloric acid, and caustic
soda to be obtained in the simplest and most economical manner, the successive
reactions forming a perfect cycle in which the complete and continuous regeneration
of the whole of the primary matters introduced with the exception of the sodium
choride, is effected while the soda and chlorine are separated.
The process consists essentially of the following operations and reactions:-
(1) A solution of sodium chloride to which is added a suitable proportion of hydro-
sulphate of ammonia produced in the manner hereinafter described, is treated by means
of carbonic acid, whereby bicarbonate of soda is precipitated, ammonium chlorido
being formed in the solution and sulphuretted hydrogen liberated
(II) The bicarbonate of soda precipitate is collected on a filter and calcined forming
sodium carbonate and liberating carbonic acid for use in the first operation ;-
Na o, no, 200
Na 0, ++
(III) The filtrate of the preceding operation containing the whole of the ammonium
chloride is next boiled with barium sulphide or other body such as sulphide of calcium,
strontium, etc., whereby chloride of barium, calcium, or strontium, etc., is formed and
hydrosulphate of ammonia which is recovered in brine for use in decomposing a
fresh quantity of sodium chloride (in operation I) the reaction being :
Az HCl + Ba S
-
Ba ClAz H' S.
(Note. Instead of directly treating the mother waters containing ammonium chloride,
the latter may be extracted in a solid form by supersaturating said waters with sodium
chloride at a temperature of 30° C and cooling them to a temperature of about 0° C.
In this case the ammonium chloride is treated as above described but with the
advantage that the reaction may be performed with a highly concentrated solution or
even dry.)
(IV) The barium or other chloride obtained is treated by one of the following
methods which consist essentially in the employment of the sulphuretted hydrogen
liberated in the first operation for converting the chloride into sulphate and
liberating hydrochloric acid and also chlorine :-
(a) The sulphuretted hydrogen evolved in operation I is passed at a red heat
and with an excess of air,, over the solid chloride obtained directly as described in the
note to operation III, or extracted by the crystallization or evaporation to dryness of

page_text: the waters of operation III. Thus in the case of barium chloride for example, barium
sulphate and hydrochloric acid are formed;
Ba Cl + HS + 4 0 = Ba O, SO³ + H CI,
(b) Or the sulphuretted hydrogen of operation I is burnt and the gases resulting
from the combustion cansed to bubble
obtained directly by operation III or
indicated in the noto to operation III.
through the solution of barium chloride
prepared with the product of the reaction
Hydrochloric acid is also formed
The barium sulphate is separated by filtration.
The hydrochloric acid remaining in solution is treated with binoxide of manganese
if chlorine is to be produced. In this reaction chloride of manganese is formed
which may be regenerated by known means.
(c) Or the barium chloride may be converted into sulphate with a direct production
of chlorine by treating it either in the dry way or in the humid way with the addition
of binoxide of manganese by means of the hydro sulphuric gases, whether burnt or
not, of operation I, the reaction according as the gases are previously burnt or not
being as follows
The chloride of manganese formed is regenerated by known means.. Instead of
directly treating the chlorides of barium, strontium, etc., by sulphurous acid- and air
in presence of the salts mentioned they may be previously converted by double
decomposition into other chlorides such as chlorides of magnesium, manganese, etc.,
eminently convertible into sulphates with production of hydrochloric acid or chlorine.
With magnesia, the sulphate for example, the reaction is as follows;
The same magnesia serves over and over again.
(Note. The above reactions (a. b. c.) can only be properly operated in presence of-
chloride of manganese, copper, iron, etc., or any other body promoting catalytically
oxidation of sulphurous acid by the oxygen of the air. This catalytic action is
described as applied to a special process in another application for Letters Patent of
even date herewith and is here described' in its general application. If for example
in the case of the reaction indicated in section (6) the chloride of manganese is .
employed as catalytic agent, the two following reactions take place ;—
(2) Ba Cl + Mn OSO³ + H Cl = Ba O, SO3 + Mn Cl + H Cl.
As explained in the other application for Letters Patent above referred to, the
chloride of manganese becomes regenerated and acts catalytically.)
(V) All these reactions lead as will be seen, to obtaining sulphate of barium,
strontium, etc. This insoluble sulphate is separated by filtration if the operation is

page_text: 2 Ba S + 2 HO = Ba O, HO + Ba S, HS.
The bodies are in solution in the water added, which on cooling yields crystals of
caustic baryta and it is this caustic baryta obtained without cost. so to speak which is
employed very advantageously for the caustification of the carbonate and more
especially of the sulphate of soda by known means. The barium sulphate formed
remains to be used again in the above operation. The mother water which is charged
more especially with hydrosulphate of sulphide of barium is added to the undecom-
posed excess of sulphide of barium to serve for the regeneration of the hydrosulphate
of ammonia by operation III and thus recover all the sulphur it contained.
General Remarks. It has been before explained that the sulphuretted hydrogen was
collected from the carbonatation apparatus (operation 1) to be used under the different
conditions explained for converting the barium, strontium, or other chlorides into
sulphates with production of hydrochloric acid or chlorine. The sulphuretted
hydrogen may however be collected before it enters the carbonatation apparatus by
previously liberating it either during the regenerating operation (operation III) or
oven previous thereto.
In the first case, a part of the carbonic acid obtained in operations II and V is
passed through tlie brine itself in which the condensation of the hydro-sulphate of
ammonia (operation III) is effected. This hydro sulphate gives up the sulphuretted
hydrogen which is afterwards utilized for operation IV.
In the second case the barium sulphide itself is treated with a part of the carbonic
acid of operations II and V, it being converted into barium carbonate with liberation
of sulphuretted hydrogen for utilizing in operation IV. The carbonate will serve
directly for operation III instead of the barium sulphide which it has replaced; it
then forms ammonium carbonate and barium chloride.
It will be understood that the invention includes the treatment of the sulphuretted
hydrogen (at whatever point of the cycle it is recovered and independently of the
means described,) together with the production of sulphur which may be collected or
burnt to produce sulphurous acid for operation IV. To this end one of the following
means is employed; (1) The sulphuretted hydrogen is passed over porous bodies in
presence of air, forming water and sulphur ;-

page_text: process, the element sulphur which is recovered on leaving the carbonatation apparatus.
This element forms an oxygenated sniphur compound capable of more readily
decomposing into chlorine or hydrochloric acid, the chlorides resulting from the
regeneration, by forming a sulplate which is regenerated in turn.
The following is a summary of the cycle of operations on which the invention is
based;
Ist. Operation. Production of Bicarbonate of Soda.
2 Ba S+2 HO= Ba O, HO + Ba S, HS.
In the successive reactions the whole of the ammonia, sulphur, baryta, and carbonic
acid (with the exception of that which passes out with the sodium carbonate) are
recovered being successively regenerated less the loss in working, to serve for the
conversion of a fresh quantity of sodium chloride or sodium carbonate and chlorine
or hydrochloric acid.
There it is true a production of one equivalent of carbonic acid in excess but this
excess is necessary for the practical working of oporation I. The ammonia employed
would be in the form of concentrated liquids or otherwise; the sulphur, baryta, and
other matters, in the form of sulphates which are converted into sulphides (operation V)
for use in operation III accompanied by the production of carbonic acid for use in
operation I. The apparatus employed is similar to those ordinarily used for like
purposes.
A. MELVILLE CLARK.
By A. M. & Win. Clark,
53, Chancery Lane, London,
Patent Agents.

page_text: COMPLETE SPECIFICATION.
An Improved Process of Manufacturing Soda by Means of Ammonia,
and Producing Carbonate of Soda, Caustic-soda, and Hydro-
chloric Acid or Chlorine.
I, ALEXANDER MELVILLE CLARK, of the firm of A. M. and Wm. Clark, of 53, Chancery
Lane, in the County of Middlesex, Fellow of the Institute of Patent Agents, do
hereby declare the nature of this invention (a communication to me from abroad by
Jean Baptiste Daguin, of 44, Rue de Château Landon, Paris, Franco, Manufacturer of
Chemical Products and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
This Invention relates to an improved process for the manufacture of soda by means
of ammonia, and the parallel and simultaneous production of sodium carbonate, caustic
soda, hydrochloric acid, and chlorine.
Before describing the invention, I will first briefly refer to the principal re-actions
which form the basis of the ammonia-soda process, as now practised
:-
(a) A solution of sodium chloride, containing a suitable proportion of ammonia, is
treated with carbonic acid forming bicarbonate of soda, which precipitates, and
ammonium chloride which remains in solution in the mother water
(b) The bicarbonate of soda precipitate is collected on a filter and on being
calcined produces sodium carbonate setting free the carbonic acid employed in the first
reaction;
Az H' Cl + Ca O = Az H' O+ Ca Cl.
The Lime is obtained by calcining limestone the carbonic acid which disengages in 2
this decomposition being utilized for the first reaction.
.
The great objection to the above process is that calcium chloride is produced a
product which is unutilizable and which entails the loss of the whole of the chlorine of
the chloride of sodium.
I am aware that it has been proposed to employ magnesia in lieu of lime for the 3
regeneration of the ammonium chloride whereby magnesium chloride is obtained which

page_text: is decomposed at a red heat by oxygen or steam forming.hydrochloric acid or chlorine,
the magnesia being regenerated. This process however is difficult of application to
the ammonia process as it would entail the production of such weak solutions of
magnesium chloride as to render their concentration very costly.
The process hereinafter described enables chlorine, hydrochloric acid, and caustic
soda to be obtained in the simplest and most economical manner, the successive,
reactions forming a perfect cycle in which the complete and continuous regeneration.
of the whole of the primary matters introduced with the exception of the sodium.
chlorido, is effected while the soda and chlorine are separated.
- דג
The process consists essentially of the following operations and reactions ;-
(1) A solution of sodium chloride to which is added a suitable proportion of hydro-
sulphate of ammonia produced in the manner hereinafter described, is treated by means
of carbonic acid, whereby bicarbonate of soda is precipitated, ammonium chloride being
formed in the solution and sulphuretted hydrogen liberated ;—
(II) The bicarbonate of soda precipitate is collected on a filter and calcined forming
sodium carbonate and liberating carbonic acid for use in the first operation ;—
Na O, HO, 2 CO³= Na O, CO + HO + CO*.
(III) The filtrate of the preceding operation containing the whole of the ammonium
chloride is next boiled with barium sulphide or other body such as sulphide of calcium,
strontium, etc., whereby chloride of barium, calcium, or strontium, etc., is formed and
hydrosulphate of ammonia which is recovered in brine for use in decomposing a fresh
quantity of sodium chloride (in operation 1,) the reaction being :-
:-
Ba Cl + HS + 4 0 = Ba O, SO³ + H Cl.
(b) Or the sulphuretted hydrogen of operation I is burnt and the gases resulting
from the combustion caused to bubble through the solution of barium chloride obtained
directly by operation III or prepared with the product of the reaction indicated in
the note to operation III. Hydrochloric acid is also formed

page_text: The barium sulphate is separated by filtration.
The hydrochloric acid remaining in solution is treated with binoxide of manganese
if chlorine is to be produced. In this reaction chloride of manganese is formed which
may be regenerated by known means.
(c) Or the barium chloride may be converted into sulphate with a direct production
of chlorine by treating it either in the dry way or in the humid way with the addition of
binoxide of manganese by means of the hydro sulphuric gases, whether burnt or not,
of operation I, the reaction according as the gases are previously burnt or not being
as follows;
(1) Ba Cl + HS + 4 0 + Mn O² -
-
Ba O, SO³ + Mn Cl + Cl + HO
The chloride of manganese formed is regenerated by known means. Instead of
directly treating the chlorides of barium, strontium, etc., by sulphurous acid and air in
presence of the salts mentioned they may be previously converted by double decom-
position into other chlorides such as chlorides of magnesium, manganese, etc., eminently
convertible into sulphates with production of hydrochloric acid or chlorine. With
magnesia, the sulphate for example, the reaction is as follows;

page_text: The bodies are in solution in the water added, which on cooling yields crystals of
caustic baryta and it is this caustic baryta obtained without cost so to speak which is
employed very advantageously for the caustification of the carbonate and more
especially of the sulphate of soda by known means. The barium sulphate formed
remains to be used again in the above operation. The mother water which is charged
more especially with sulphydrate (i.e. hydrosulphate of sulphide) of barium is added to
the undecomposed excess of sulphide of barium to serve for the regeneration of the
hydrosulphate of ammonia by operation III and thus recover all the sulphur it
contained.
General Remarks. It has been before explained that the sulphuretted hydrogen was
collected from the carbonatation apparatus (operation 1) to be used under the different
conditions explained for converting the barium, strontium, or other chlorides into
sulphates with production of hydrochloric acid or chlorine. The sulphuretted hydrogen
may however be collected before it enters the carbonatation apparatus by previously
liberating it either during the regenerating operation (operation III) or even previous
thereto.
In the first case a part of the carbonic acid obtained in operations II and V. is
passed through the brine itself in which the condensation of the hydro-sulphato of
ammonia (operation III) is effected. This hydro sulphate gives up the sulphuretted
hydrogen which is afterwards utilized for operation IV.
In the second case the barium sulphide itself is treated with a part of the carbonic
acid of operations II and V, it being converted into barium carbonate with liberation
of sulphuretted hydrogen for utilizing in operation IV. The carbonate will serve
directly for operation III instead of the barium sulphide which it has replaced; it
then forms ammonium carbonate and barium chloride.
It will be understood that the invention includes the treatment of the sulphuretted
hydrogen (at whatever point of the cycle it is recovered and independently of the
means described) together with the production of sulphur which may be collected or
burnt to produce sulphurous acid for operation IV. To this end one of the following
means is employed; (1) The sulphuretted hydrogen is passed over porous bodies in
presence of air, forming water and sulphur
(2) Or a portion of the sulphurous acid already produced in the process is brought
into the presence of the sulphuretted hydrogen to be converted, water and sulphur being
formed as before:
It will be seen from the foregoing that one of the characteristics of the invention
consists in introducing into the fundamental reactions of the ordinary ammonia process,
the element sulphur which is recovered on leaving the carbonatation apparatus. This
element forms an oxygenated sulphur compound capable of more readily decomposing
into chlorine or hydrochloric acid the chlorides resulting from the regeneration, by
forming a sulphate which is regenerated in turn.
The following is a summary of the cycle of operations on which the invention is
based;-
1st Operation. Production of Bicarbonate of Soda
Na Cl + Az HS + 2 CO2 + 2 HO = Na O, HO, 2 CO² + Az H* Cl + HS.

page_text: IIIrd Operation. Regeneration of hydrosulphate of ammonia with or without the
separation of the solid ammonium chloride from the mother waters-
(in presence of the salts indicated Mn Cl or others) or lastly;—
In the successive reactions the whole of the ammonia, sulphur, baryta, and carbonic
acid (with the exception of that which passes out with the sodium carbonate) are
recovered, being successively regenerated less the loss in working, to serve for the
conversion of a fresh quantity of sodium chloride or sodium carbonate and chlorine or
hydrochloric acid.
There is, it is true, a production of one equivalent of carbonic acid in excess, but this
excess is necessary for the practical working of Operation L. The ammonia employed
would be in the form of concentrated liquids or otherwise; the sulphur, baryta, and
other matters in the form of sulphates which are converted into sulphides (Operation V)
for use in Operation III accompanied by the production of carbonic acid for use in
operation I.
The apparatus employed is similar to those ordinarily used for like purposes.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:
1st. In the process of manufacturing soda by means of ammonia, the introduction
throughout the cycle of operations of the element sulphur which forms an oxygenated
sulphur compound capable of more readily decomposing into chlorine or hydrochloric
acid, the chlorides resulting from the regeneration, by forming a sulphate which is
regenerated in its turn.
2nd. The herein described process of manufacturing soda by means of ammonia
with a parallel and simultaneous production of carbonate of soda, caustic soda, hydro-
chloric acid and chlorine, consisting in the following continuous series or cycle of
operations;
(a) Precipitation of bicarbonate of soda in a brine, to which has been added
hydrosulphate of ammonia with liberation of sulphuretted hydrogen.
(b) Calcination of the bicarbonate of soda with production of carbonate of soda
and liberation of carbonic acid.
(c) Treatment of the mother waters charged with ammonium chloride of
Operation I, by means of barium or other sulphide with production of hydro-
sulphate of. ammonia and barium or other chloride, or treatment by the same
barium or other sulphide of the solid ammonium chloride extracted on cooling
the mother waters supersaturated with chloride of sodium.

page_text: (d) Treatment of the barium or other chloride by means of oxygen and sulphur-
etted hydrogen (whether previously converted or not into sulphurous acid)
with formation of barium or other sulphate and liberation of hydrochloric
acid or chlorine.
(e) Decomposition of the barium or other sulphate by means of charcoal with
production of barium or other sulphide and liberation of carbonic acid.
(f) Economical preparation of caustic baryta by the lixiviation of the barium.
sulphide for the production of caustic soda.
100
1000
A. MELVILLE CLARK.
By A. M. & Wm. Clark,
53, Chancery Lane, London,
Patent Agents.