Improvements in Obtaining Ammonia, Chlorine, and Hydrochloric Acid from Ammonium Chloride, and in the Apparatus Employed therein
Year: 1889

page_text: Date of Application, 5th Oct., 1889
Complete Specification Left, 2nd July, 1890-Accepted. 2nd Aug., 1890
PROVISIONAL SPECIFICATION.
Improvements in Obtaining Ammonia, Chlorine, and Hydrochloric
Acid from Ammonium Chloride, and in the Apparatus Employed
therein,
I, FREDERICK BALE, of Coventry Hospital, Droitwich, Worcestershire, Chemist, do
hereby declare the nature of this invention to be as follows:-
This invention has for its object, the improvement of the methods of obtaining
ammonia, chlorine and hydrochloric acid, from ammonium chloride, for which I have
obtained letters patent, numbered respectively 14,000, and 14,001; and 'dated
October 15th 1887. The chief feature in this process consists, in the intimate
mixture of ammonium chloride in powder, with metallic oxide in powder, a low
temperature, involving the non-volatilization of the ammonium chloride, and its
complete decomposition, at a temperature considerably below that required for its
volatilization, together with the use of the atmospheric air, for clearing the retort from
moisture and ammonia.
I now find, that the following discoveries and processes, will give good results, and
all the advantages of action and reaction obtained by substances in solution, and other
gains.
1. If the haloid salts be taken and heated, they nearly all fuse or melt, at a
temperature below 1000° C. Any required temperature between 200° C. and 600° C.,
may be obtained from them, or from certain of their mixtures, the melting point of
their mixtures being generally below their individual melting points. These with the.
furnace below mentioned form my bath or decomposer.
2. Other salts, or mixtures of salts, besides these, whose fusion points are within
this range of temperature, may likewise be used, with more or less advantage.
3. Metals as zinc, tin, lead, bismuth &c. fusible metal, or a mixture of these whose
fusion points are within this range of temperature, may likewise be employed with
more, or less advantage.
I prefer those salts, hydrocarbons, metals, or elements, which at the temperature
required, are sufficiently mobile when melted, as to allow the oxides or salts and the
ammonium chloride to easily come into intimate contact, when added to them in their
molten condition, and which are not affected injuriously, by the ammonia, chlorine or
hydrochloric acid evolved, nor injuriously affects the same. One of the best for this
purpose, and which I prefer, is the chloride of zinc, but many others are available.
Into the bath thus obtained by fusing the chloride of zinc, I place preferably, the
oxide of manganese, which remains in suspension in the fused chloride of zinc. The
whole may be contained in an iron retort, or other suitable furnace, which I call my
decomposer.
Besides the oxides of manganese other oxides may be used, with more or less
advantage; as the oxides of barium, strontium, calcium, magnesium, zinc, lead, copper,
aluminium, iron, bismuth, tin, nickel, cobalt, and others of similar properties; and
always preferably in powder. Many salts, formed from these oxides, whose acids are
fixed at the temperatures employed, may be used sometimes with advantage.
Mixtures of the above may often be used with advantage.
The haloid salts may be used alone, when sufficiently fusible or mobile, at the
temperature required, as those of zinc, magnesia &c. by converting them partly into
oxide on the passage through them of air, and then treating the mixture of chloride
and oxide thus obtained, with chloride of ammonium, as described below.
Into the decomposer thus formed, solid ammonium chloride is fed in by portions at
a time, or by a continuous feeder. I prefer to use both the solid chloride of
ammonium and the oxides in powder. As the ammonic chloride is led into the
1

page_text: decomposer, its ammonia is evolved, and may be passed into the absorbing apparatus,
containing a solution of common salt. The chloride or oxy-chloride of the metal is
formed.
The temperature during the evolution of the ammonia should be kopt below 350° C.
when the oxide of manganese is used, if dry air is to be passed through the molten
mass, as it may be, during, and after, the evolution of the ammonia, to remove all
moisture formed in the decomposition of the chloride of ammonium, and thus prevent
the formation of hydrochloric acid, on the passage of dry air, when chlorine is
required.
When the ammonia is quite evolved, the temperature is raised, and dry air is
passed into, and through the molten mass in the decomposer. The chlorine is at once
evolved, and its evolution goes on till the chloride, or oxychloride of manganese or
other metal is decomposed, and the oxide of manganese or other metal formed, and
remains in suspension in the fused chloride, as at first, and from this point the round
of operations goes on continually. The chlorine may be led into a bleaching powder
chamber or otherwise utilized. If the air bo carefully passed the mixed gases evolved
contains from 12 to 20 per cent. of chlorine.
The air may be blown through the molton chloride by a blower or engine. For this
purpose the furnace should be lined with some refractory substance, as siliceous sand-
stone or ganister, and should contain, a false bottom, above the real one, perforated;
with holes, through which air may be blown, as in the Weldon process, for the
regeneration of the manganese; or the air may be driven through the molten mass, as
it is done in the Bessemer, steel converter, or a suitable perforated tube, containing
radial arms, is made to revolve through the molten mass aud deliver air into it at the
same time.
When hydrochloric acid is required, steam superheated if necessary is passed into
the residue left, after the evolution of the ammonia, instead of air, when hydrochloric
acid, is at once evolved,
I have only mentioned one retort or furnace in which both the operations for the
evolution of the ammonia, and hydrochloric acid, or chlorine, may be carried on; but
it is evident that the evolution of the ammonia may be carried on in one apparatus or
furnace, and the evolution of the hydrochloric acid or chlorine, in another, at d similar
furnace; and often with advantage, especially when a chloride is formed in the
decomposer; which easily fuses at the temperature employed. For this purpose
the chloride, or oxychloride formed in the decomposer, by the decomposition of the
ammonium chloride is removed as formed, and placed in the regenerator (as I call the
second furnace for the regeneration of the oxide from the chloride) as above described,
and treated with steam for the production of hydrochloric acid, or with dry air for
the chlorine. Some of the chlorides or oxy-chlorides, as those of zinc magnesia, &c.
readily fuse, and may be allowed to flow away from the decomposer into the
regenerator by their own gravity.
Almost every apparatus, retort, cylinder, or pan, which provides for the evolution
of a gas or vapour and the removal of a solid or liquid, would do for this purpose.
A very suitable apparatus for this purpose, is a large circular iron pan or cylinder,
after the pattern of those used in the manufacture of butter salt, but inuch deeper, in
which the salt or oxide, worked out in pockets at the side, by a fan which revolves,
through the pan, and thus removed and transferred to the regenerator for the evolution
of its chlorine, or hydrochloric acid, and a proportion of the fused chloride, or other
fused salt with its admixed oxide, may be returned from the regenerator into the
decomposer. The regenerator should also have a perforated false bottom or a fan
carrying perforated tubes, for the delivery of air into the molten mass. The process
may be made continuous by removing, or allowing to flow away, the chloride from
the decomposer, and replacing an equivalent of oxide from the regenerator.
By the above means, and appliances, I get all the advantages of chemical action,
and reaction, obtained by substances, in solution; being thus more complete, more
easily effected, with a better command, of temperature, and less labour, and fuel, than
when these reactions, take place in the dry way. The percentage yield, of chlorine,

page_text: by these means is much greater, the reduction of the oxides, when they become
sesquioxide (M, O) is more complete, and the elimination of moisture, from the
retort, more easily effected.
The above principles and discoveries, include several independent methods of
working, as -
(A) With one retort, or furnace, for the evolution, of the ammonia, chlorine, or
hydrochloric acid.
(1) Where the chloride may be used alone, in the melted condition, and which, on
the passage of air through its molten mass, may be partly converted into oxide, and
its chlorine evolved, and then receive its charge of ammonium chloride.
(2) Where the haloid or other salt, metal &c. may be used in the melted condition
mixed with, or holding in suspension, in its fused state, other oxide, or oxides, as
described, then receiving its charge of ammonium chloride, and completing the
operations, for the Cl, and the H Cl, as described.
(3) Where the ammonium chloride and oxide or oxides, are mixed in powder and
introduced together, into the molten mass of haloid or other salt &c. and completing
the operations as described.
(B) With two retorts in use, the decomposer for the evolution of the ammonia, and
the regenerator for the evolution of the chlorine and hydrochloric acid.
(1) Where the residue left after the evolution of the ammonia, remains infusible,
and is taken in the solid form from the retort, either entirely or by portions, at a time
and placed in the regenerator, and an equivalent portion returned from the regenerator
to the retort or decomposer.
(2) Where the residue left after the evolution of the ammonia, becomes fluid, or
melts at the temperature required; and is allowed to flow away entirely or by portions
at a time, as formed, into the regenerator from the decomposer, and an equivalent
portion, returned from the regenerator. The evolution of the chlorine and hydro-
chloric acid, is confined to the regenerator. Several decomposers may thus be worked
with one regenerator.
The depth or density of the colour, produced, in the fused mass, by the formation o
the oxide on the passage of steam or air, will determine, when the blowing should
cease, and sufficient oxide formed to receive the charge of ammonium chloride. This
applies when all the operations are performed, in one retort or decomposer for
The oxide of zinc is yellow when hot,
manganese is browu,
magnesium is white,
"
39
"
"
":
"
nickel is grey &c. &c.,
and by keeping samples, of or painted, copies of the colour of these oxides, when
TREDERICK BALE.
TREDERICK BALE.
COMPLETE SPECIFICATION.
Improvements in Obtaining Ammonia, Chlorine, and Hydrochloric
Acid from Ammonium Chloride, and in the Apparatus Employed
therein.
I, FREDERICK BALE of Coventry Hospital Droitwich, Worcestershire, Chemist, do
hereby declare the nature of this invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement :-
This invention has for its object the improvement of the methods of obtaining
ammonia, chlorine, and hydrochloric acid, from ammonium chloride for which I have
obtained letters patent numbered respectively 14,000 and 14,001 and dated Oct. 15th

page_text: 1887. The chief feature in this process consists in the intimate mixture of ammonium
chloride in powder with metallic oxide in powder, a low temperature involving the
non-volatilization of the ammonium chloride, and its complete decomposition at a
temperature considerably below that required for its volatilization together with the
use of the atmospheric air, for clearing the retort from moisture and ammonia.
I now find, that the following discoveries and processes, will give good results, and
all the advantages of action and reaction, obtained by substances in solution, and other
gains.
1. If the haloid salts be taken and heated they nearly all fuse or melt, at a tem-
perature below 1000° C. Any required temperature between 200° C. and 600° C.
may be obtained from them, or from certain of their mixtures by fusion the melting
point of their mixtures being generally below their individual melting points. These
with the furnace and oxides below mentioned form my bath or decomposer.
2. Other salts, or mixtures of salts besides these whose fusion points are within this
range of temperature may likewise be used with more or less advantage.
3. Metals as zinc, tin, lead, bismuth, &c. fusible metal ora mixture of these, whose
fusion points are within this range of temperature may likewise be employed with
more or less advantage.
prefer those salts, hydrocarbons, metals, or elements, which, at the temperature
required are sufficiently mobile when melted as to allow the oxides or salts and the
ammonium chloride to easily come into intimate contact when added to them in their
molten condition and which are not affected injuriously by the ammonium chloride or
One of the best for this
hydrochloric acid evolved nor injuriously affects the same.
purpose and which I prefer is the chloride of zine, but many others are available.
For obvious reasons, the use of haloid salts would be practically limited to those of
the chlorides.
Into this bath thus obtained by fusing the chloride of zinc, I place preferably, the
oxide of manganese which remains in suspension in the fused chloride of zinc. The
whole may be contained in an iron retort or other suitable furnace which I call my
decomposer.
Besides the oxides of manganese other oxides may be used with more or less
advantage; as the oxides of barium, strontium, calcium, magnesium, zinc, lead, copper,
aluminium, iron, bismuth, tin, nickel, cobalt and others of similar properties, and
always preferably in powder. Many salts formed from these oxides, whose acids are
fixed at the temperature employed may be used sometimes with advantage.
Mixtures of the above may often be used with advantage.
The haloid salts may be used alone when sufficiently fusible or mobile, at the
temperatures required as those of zinc, magnesia &c. by converting them partly into
oxides on the passage through them of air and then treating the mixture of chloride
and oxide thus obtained with chloride of ammonium as described below.
Into the decomposer thus formed solid ammonium chloride is fed by portions at a
time, or by a continuous feeder. I prefer to use both the solid chloride of ammoniuma
and the oxides in powder. As the ammonium chloride is led into the decomposer its
ammonia is evolved and may be passed into the absorbing apparatus containing a
solution of common salt. The chloride or oxy chloride of the metal is formed.
The temperature during the evolution of the ammonia should be kept below 350° C.
when the oxide of manganese is used, if dry air is to be passed through the molten
mass as it may be during and after the evolution of the ammonia, to remove residual
ammonia and all moisture formed in the decomposition of the chloride of aminonium,
and thus prevent the formation of hydrochloric acid, on the passage of dry air, when
chlorine is required.
When the ammonia is quite evolved the temperature is raised and hot dry air is
passed into and through the molten mass in the decomposer. The chlorine is at once
evolved and its evolution goes on till the chloride or oxy chloride of manganese or
other metal is decomposed, and the oxide of manganese or other metal formed and
remains in suspension in the fused chloride as at first, and from this point the round
of operations goes on continually. The chlorine may be led into a bleaching powder

page_text: chamber or otherwise utilized. If the air be carefully passed the mixed gases evolved
contain at first from 12 to 20 per cent. of chlorine.
For
The air may be blown through the molten chloride by a blower or engine.
this purpose the furnace should be lined with some refractory substance as siliceous
sandstone or ganister, and should contain a false bottom above the real one perforated
with numerous holes, and through the space between the real and false bottom, air may.
be blown as in the Weldon process for the regeneration of the manganese, or the air
may be driven through the molten mass as it is done in the Bessemer steel converter,
or a suitable perforated tube containing radial arms, is made to revolve or not, through
the molten mass, and deliver air into it at the same time.
To preserve the retorts as much as possible from the corrosive action of the fused
zinc chloride, the ammonium chloride chlorine, and hydrochloric acid, they should be
lined with a layer of the fused chloride of a metal, whose fushion point is considerably
above the temperature required for these reactions.
When hydrochloric acid is required, steam, superheated if necessary, is passed into
the residue left after the evolution of the ammonia, instead of air when hydrochloric
acid is at once evolved.
I have only mentioned one retort or furnace in which both the operations for the
evolution of the aminonia, and hydrochloric acid, or chlorine may be carried on, but it
is evident that the evolution of the ammonia may be carried on in one apparatus or
furnace and the evolution of the hydrochloric acid or chlorine in another, and similar
furnace, and often with advantage, especially when a chloride is formed in the
decomposer, which easily fuses at the temperature employed. For this purpose
the chloride or oxy chloride formed in the decomposer, by the decomposition of the
ammonium chloride, is removed as formed and placed in the regenerator (as I call
the second furnace for the regeneration of the oxide from the chloride) as above
described and treated with steam for the production of hydrochloric acid or with dry
air for the chlorine. Some of the chlorides or oxy chlorides as those of zinc, copper,
magnesia &c. readily fuse and may be allowed to flow away from the decomposer into
the regenerator by their own gravity.
Almost every apparatus, retort cylinder, or pan which provides for the evolution of
a gas or vapour, and the removal of a solid or liquid would do for this purpose.
A very suitable apparatus for this purpose is a large circular iron pan or cylinder
after the pattern of those used in the manufacture of butter salt, but much deeper, in
which the salt or oxide is worked out in pockets at the side by a fan which revolves
through the pan and thus removed and transferred to the regenerator for the evolution
of its chlorine or hydrochloric acid and a proportion of the fused chloride or other
fused salt with its admixed oxide may be returned from the regenerater into the
decomposer. The regenerater should have a perforated false botton or a fan carrying
perforated tubes for the delivery of air into the molten mass. The process may be made
continuous by removing or allowing to flow away the chloride from the decomposer
and replacing an equivalent of oxide from the regenerater. But I prefer the single
retort and apparatus described below and in the accompanying figure. If several of
such retorts are worker in series the hot gases issuing from one retort or series,
may be passed into and utilized in another when necessary, as mentioned in my
previous patents.
By the above means and appliances I get all the advantage of chemical action and
reaction obtained by substances in solution being thus more complete, more easily
effected, with a better command of temperature, and less labour and fuel, than when
these reactions take place in the dry way. The percentage yield of chlorine by
these means, is much greater, the reduction of the oxides when they become sesqui-
oxide (M, O) is more complete and the elimination of moisture from the retort more
easily effected.
The above principles and discoveries include several independent methods of
working, as
A. With one retort or furnace for the evolution of the ammonia, chlorine, or
hydrochloric acid and called the decomposer.

page_text: (1) Where the chloride may be used alone in the melted condition, and which on
the passage of air through its molten mass may be parily converted into oxides and
its chlorine evolved and then receive its charge of ammonium chloride.
(2) Where the haloid or other salt metal &c. may be used in the melted condition
mixed with or holding in suspension in its fused state other oxide or oxides as
described then receiving its charge of ammonium chloride and completing the
operations for the chlorine and hydrochloric acid as described.
(3) Where the ammonium chloride and oxide or oxides are mixed in powder and
introduced together into the molten mass of haloid or other salts &c. and completing
the operations as described.
B. With two retorts in use, the decomposer for the evolution of the ammonia, and
the regenerater for the evolution of the chlorine, and hydrochloric acid.
(1) Where the residue left after the evolution of the ammonia remains infusible and
is taken in the solid form from the retort or decomposer either entirely or by portions
at a time and placed in the regenerator,and an equivalent portion of oxide &c.returned
from the regenerater to the retort or decomposer.
(2) Where the residue left after the evolution of the ammonia becomes fluid or.
melis at the temperature required; and is allowed to flow away entirely or by portions
at a time as formed into the regenerater from the decomposer, and an equivalent
portion of oxide &c. returned from the regenerator. The evolution of the chlorine
and hydrochloric acid is confined to the regenerater. Several decomposers may thus
be worked with one regenerater.
'The depth or density of the colour produced in the fused mass by the formation of
the oxide on the passage of steam or air will determine when the blowing should cease
and sufficient oxide formed to receive the charge of ammonic chloride. This applies
when all the operations are performed in one retort or decomposer; for
The oxide of zinc is yellow when hot,
The oxide of manganese is brown when hot,
The oxide of magnesium is white when hot,
The oxide of nickel is grey when hot,
and by keeping samples of, or painted copies of the colour of these oxides when
formed in sufficient quantity in the fused mass, the time of blowing may be well.
determined and regulated.
When two retorts are used (A & B) this would be unnecessary, as the blowing of
air through the molten mass in the regenerater need not cease.
In order to explain the carrying out of my process I have appended here to a
sketch of apparatus and plant. The accompanying figure is a section of the entire
apparatus.
A is the retort filled to about with fused chloride of zinc containing its proportion
of oxide or salt to about one fourth of the weight of the fused chloride. The retort
is of iron lined on the inside with fused chloride or ganister.
B is the air blast pipe connected with blower for delivering air into fused mass.
b, b, are air holes in false bottom.
C passage to ammonia absorbing apparatus controlled by plug c.
D passage to chlorine or hydrochloric acid chambers and controlled by plug d.
When c is opened is shut and the converse.
E is the discharging orifice.
H is the hopper for supplying solid ammonium chloride to retort through the
valve or plug .
I will now describe the mode of action which is as follows:-
The chloride of zinc obtained from heating a mixture of zinc oxide and ammonium
chloride is much preferable being more mobile than the commercial article and allows
the molecules to come more rapidly into intimate contact. The molten chloride of
zinc is placed in or formed thus in the retort. Into the molten zinc chloride is placed
the proportional quantity of oxide or manganese or other oxide or salt generally
about one fourth the weight of fused chloride will do. The furnace is raised to the
requisite temperature, namely below 350°C. and ammonium chloride is introduced

page_text: from the hopper H in suitable quantities, the hopper is then closed. The ammonium
chloride falling into the mixture of zinc chloride and oxide nixes with them is
decomposed, its ammonia evolved, and the chloride of the metal formed. The tem-
perature is kept below 350° C. and dry air is passe 1 through the molten mass from the
commencement of the evolution of the ammonia, or towards the end only, as desired,
thus reinoving the ammonia as formed, and at the same time carrying off the moisture
formed from the decomposition of the animonia chloride, thus preventing the loss of
ammonia, and the formation of hydrochloric acid afterwards at the higher temperature.
When this is completed the plug or valve c leading to the ammonia absorbing
apparatus is shut and d, leading to the chlorine conduit is opened. The temperature
of the furnace is now raised above 350° C. to 550° C. and the chlorine is evolved.
The blowing of the air through the molten mass goes on till (in case of manganese) it
becomes distinctly reddish brown when sufficient oxide will have been formed in the
molten mass to begin the operations afresh, but before so doing the temperature is
lowered below 350° C. by cold air passing through the mass. The chlorine will now
cease to be evolved, and any trace of free chlorine in the mass or retort will be
expelled before adding the charge of ammonium chloride. The valve d leading to the
chlorine or hydrochloric acid conduit is now shut, and c, leading to the ammonia
absorbing apparatus is opened. The hopper H is now opened and the requisite quantity
of ammonium chloride admitted and the valve / shut. Steam is passed into the fused
mass instead of air, when hydrochloric acid is required, and the same precautions taken
to clear the retort and mass from free hydrochloric acid by blowing dry air through
them before adding the charge of a'nmonium chloride. The raising and lowering of
the temperature will be unnecessary when two retorts are used (A & B) as both would
be kept at their respective temperatures.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I wish it to be understood
that I make no claim in this application for anything by itself set forth or claimed in
my previous patents.
I am also aware that the process of oxidization by delivering air through solutions
of salts or through water containing oxides in suspension as in Weldon's process and
also through molten iron as in Bessemer's process is not new, and I make no claim
for these processes, but only for their use and application substantially as heroin set
forth.
The process also of passing dry air over chlorides to obtain chlorine, and steam over
chlorides to obtain hydrochloric acid as described in my previous patents is not new,
only as combined with other processes and discoveries as therein and heroin set
forth.
I have found after numerous and repeated experiments that the chief difficulties
incidental to the process herein described namely the complete elimination of free
ammonia, chlorine, hydrochloric acid and moisture from the molten mass and retort is
simply and effectually accomplished by the use of atmospheric air as herein described
I therefore declare that what I claim is :-
1. The process of obtaining ammonia, chlorine and hydrochloric acid from ammonium
chloride which consists in fusing in a suitable retort the chloride of zinc or other
fusible compound or element adding to the fused salt, compound, or element the oxide
of manganese or other oxide or salt as described which remains dissolved or suspended
in the fused mass, the temperature being kept below 350° C. when manganese is the
oxide used, then adding the charge of ammonium chloride whereby the ammonia is
evolved then passing cold and dry air through the molten mass to remove residual
ammonia and moisture, then raising the temperature as described by passing hot and
dry air through the same for the chlorine, or steam for the hydrochloric acid then
clearing the mass and retort from free chlorine or free hydrochloric acid by lowering
the temperature below 350° C. by passing cold and dry air then adding the charge of
ammonium chloride and beginning the round of operations anew.

page_text: 2. The processes described under (A & B) for the manufacture of ammonia, chlorine,
and hydrochloric acid from ammonium chloride.
3. In the manufacture of ammonia, chlorine, and hydrochloric acid from aminonium
chloride, the use of a fused salt, compound, or element, as a medium for carrying on
the reactions for the ammonia, chlorine, and hydrochloric acid as described.
4. The improvement in the processes of obtaining ammonia, chlorine, and hydro-
chloric acid from ammonium chloride which consists of carrying on these processes in
retorts or chambers lined with a fused chloride or other salt to withstand the corrosive
action of the chloride of zinc chlorine and hydrochloric acid and whose fusion point is
above the temperature required for these reactions.
5. The use in the manufacture of ammonia chlorine and hydrochloric acid from
ammonium chloride of the apparatus herein described, and the method of delivering
air into the molten mass by means of a furnace with a false bottom perforated with
numerous holes, or by perforated or other tubes dipping into the molten mass
substantially as described.
6. In the manufacture of ammonia chlorine and hydrochloric acid from ammonium
chloride the use of atmospheric air either cold or dry or hot and dry for the elimination
of residual and free ammonia, chlorine, hydrochloric acid and moisture from the
molten mass and retort and for otherwise regulating the temperature of the same as
described.
FREDERICK BALE,
Coventry Hospital, Droitwich..