Improvements in Obtaining Ammonia and Chlorine from L Ammonium Chloride.
Year: 1886

page_text: Improvements in Obtaining Ammonia and Chlorine from
L
Ammonium Chloride.'
I LUDWIG MOND, of Winnington Hall, near Northwich, Cheshire, Manufac-
turing Chemist, do hereby declare the nature of my invention to be as follows: —
If the vapour produced by volatilizing ammonium chloride is brought in
contact, at an elevated temperature, with protoxyde of nickel or with one of
numerous other metallic oxides or a mixture or combination of them the hydro-
chloric acid or chlorine combines with the oxide or its metal, and the ammonia
passes off. Also if the chloride or oxychloride so formed is exposed at a suitable
temperature to the action of air or oxygen it is again converted into oxide, and
chlorine is given off.
I carry out my invention based on these facts in the following manner :-
Ammonium chloride is volatilized by the application of heat and the vapour so
produced is passed over or through the protoxyde of nickel while heated to about
400 degrees centigrade.
The Ammonium Chloride may be mixed with the protoxyde of nickel before heat
is applied but this is not necessary.
In either case the hydrochloric acid leaves the ammonia and is retained by the
oxide, while the ammonia passes on and is utilized or absorbed in any convenient
manner.
An inert gas containing as little as possible of steam, oxygen or hydrogen is now
passed through to drive out the remaining ammonia, and then air preferably
previously dried and heated is passed over or through the material heated to a
suitable temperature. The oxygen combines with the nickel forming an oxide,
which can be used continually over again in this process, and the chlorine is given
off mixed with a certain quantity of bydrochloric acid and can be utilized in any
desirable manner.
Besides the protoxyde of nickel the oxides of iron, cobalt, manganese, alumina,
copper, bismuth, magnesium and other metals can be advantageously applied
according to circumstances.
The temperature for the production of chlorine varies with the oxide employed,
and can easily be ascertained by any practical man.
To increase the active surface and to obtain the material in a convenient form
for working this process, it is advantageous to impregnate pumice stone or other
porous material with the molten chloride or with a solution of the chloride of the
Prine 71

page_text: metal to be employed and after drying to heat the same in a current of air so as to
produce the oxide, or the oxide can be formed into lumps of convenient size by
mixing it with inert agglomerating substances and drying or by agglomerating
it with the help of the solution of the chloride of the metal employed or any other
salt and subsequently drying and heating in a current of air, or otherwise.
Both operations can be carried on in a single retort or apparatus without
removal of the oxide or the oxide can be treated with ammonium chloride in
one retort or apparatus and the treatment with air be carried on in another.
Iron or clay retorts preferably set vertically or obliquely are a convenient
apparatus for this purpose.
Certain of the chlorides of the metals above named, such as the chlorides of iron
and manganese, form when heated in a current of air oxydes containing more
oxygen than is desirable for the first part of this process, as this excess of oxygen
destroys a part of the ammonia passed over the oxyde.
When it is otherwise desirable to use the oxydes named I overcome this difficulty
by passing over or through the oxyde, after the treatment with air, a current of
gas containing hydrogen or carbonic oxide or a mixture of these such as producer
gas. These gases reduce the oxyde present to a lower oxyde which no longer
acts upon ammonia and which can now be used without disadvantage in the first
part of my process.

page_text: Improvements in Obtaining Ammonia and Chlorine from
Ammonium Chloride.
I, LUDWIG MOND of Winnington Hall near Northwich, Cheshire, Manufac-
turing 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:-
If the vapour produced by volatilizing ammonium chloride is brought into,
contact at an elevated temperature with protoxide of nickel, or with one of
numerous other metallic oxides, or a mixture or combination of them the hydro-
chloric acid or chlorine combines with the oxide or its metal, and the ammonia
passes off.
Also if the chloride or oxychloride so formed is exposed at a suitable
temperature to the action of oxygen or air, it is again converted into oxide,
and chlorine is given off.
I carry out my invention based on these facts in the following manner;
Ammonium chloride is volatilized by the action of heat and the vapour so
produced is passed over or through protoxide of nickel while heated to about
400 degrees Centigrade. The exact temperature required differs, however, with
different oxides.
The ammonium chloride may be mixed with the protoxide of nickel before heat
is applied, but this is not necessary. On the contrary if the ammonium chloride
be separately volatilized, and passed in the form of vapour over the oxide, the
entire cycle of operations can be repeatedly performed in the same chamber, and
without disturbing the position of the oxide or chloride as the case may be,-a
decided advantage.
Whichever way the chloride of ammonium be applied, the chlorine in the vapour
is retained by the oxide, while the ammonia is set free and passes on, and can be
utilized or absorbed in any convenient manner.
An inert gas, such as producer gas, or the gas which leaves the absorbing
apparatus of the ammonia soda process, containing as little oxygen, hydrogen, or
steam as possible, is now passed through to drive out the remaining ammonia.
Since filing the provisional Specification, I have found, and have protected under
another application, that it is desirable after admitting the neutral gas, to produce
a partial vacuum, and if necessary, alternate the introduction of neutral
gas, and
the, production of the partial vacuum, in order to expel the ammonia more
completely.
Air preferably previously carefully dried and heated to about 500 degrees is
now passed over or through the material, heated to a suitable temperature.
The oxygen combines with the nickel forming an oxide which can be used
continually over again in this process, and the chlorine is given off, and can be
utilized in any desirable manner.
Besides the protoxide of nickel which I prefer to any other, the oxides of cobalt,
copper, zinc, magnesium iron, manganese, aluminium, bismuth, and other heavy

page_text: metals possessing similar chemical properties to those named, or a mixture of these
can be used. Also as I have discovered since filing the provisional specification,
and have protected under another application, some of the combinations of one or
more of these metals with polybasic acids, such as silicic, phosphoric, tungstic,
boric, antimonic, or molybdic acids (those salts only being available which are not
volatile, and preferably not fusible at the temperature employed) can more or less
advantageously be applied for this purpose. I find, however, that those substances
are best which are only capable of existing at one grade of oxidation at the
temperatures employed, such as protoxide of nickel, which will not form a higher
oxide at these teinperatures, and alumina of which only one oxide is known.
When oxide of manganese, or of iron, or of other metals having several oxidation
grades is employed, considerable loss of ammonia is incurred, unless special measures
be taken to reduce the higher oxide before introducing the ammonium chloride, as
when the vapour of ammonium chloride is passed over the higher oxide, this is
reduced by the ammonia contained in the vapour, and a considerable portion of
the ammonia is thus destroyed and lost.
When it is otherwise desirable to use the oxides named, I overcome this difficulty.
by passing over or through the oxide after the treatment with air, a current of gas
containing hydrogen or carbonic oxide, or a mixture of these such as producer gas.
These gases reduce the oxide present to a lower oxide, which no longer acts upon
ammonia, and which can now be used without disadvantage in the first part of my
process.
The temperature for the production of chlorine varies with the oxide employed,
and can easily be ascertained by any practical man.
To increase the active surface, and to obtain the material in a convenient form
for working this process, it is advantageous to impregnate pumice-stone or other
porous inert material with the molten chloride or a solution of the chloride of the
metal to be employed, and after drying to heat the same in a current of steam or
air, so as to convert the chloride into oxide or the oxide can be formed into lumps
or balls of convenient size by agglomerating it with the help of a solution of the
chloride of the metal employed, or a solution of sugar, gum, or similar substance,
and subsequently drying and heating in a current of steam or air, or by mixing the
oxide with inert agglomerating substances, and drying, or otherwise.
I find it advantageous to mix some sawdust with the substance to be made into
balls, which is subsequently burnt on heating in a current of air, and leaves the
balls more porous.
Both operations can be carried on in one or the same retort or apparatus, without
removal of the oxide, or the oxide can be treated with ammonium chloride in oneė
retort or apparatus, and the treatment with hot air be carried on in another.
A convenient apparatus for carrying out this invention consists of cast iron
retorts lined inside with thin -earthenware tiles. A number of these retorts may
be conveniently set in one common furnace, heated by direct fire, or preferably
by generator gas. I prefer to put the retorts obliquely into the furnace at an
angle of about 30 degrees. The retorts pass through the walls of the furnace at
both sides, and are at both ends provided with covers, and also with openings for
the inlet and outlet of gases, which latter are by means of taps or valves connected
to the sources of the gases to be employed, and to the apparatus used for absorbing
or otherwise utilizing the gases produced.
These retorts are filled to about one half with balls or lumps of protoxide of
nickel or other active material prepared as herein before described, the upper part
of the retort remaining empty. In commencing the operation, the retorts and
contents are heated to about 400 degrees Centigrade, and the empty part of the
retorts is then filled with solid ammonium chloride, and the cover is immediately
put on. The temperature is maintained at about 400 degrees centigrade, until all
the ammonium chloride is volatilized, and the ammonia issuing from the lower end
of the retort is conducted to a convenient apparatus for absorbing it in a solution
of chloride of sodium or otherwise. ..
}

page_text: An inert gas, such as is herein before described is now passed through the retort
to expel the ammoniacal gas remaining in it, and this is also let into the absorbing
apparatus. By means of a vacuum pump placed in the conduit for the ammoniacal
gas, a partial vacuum is produced inside the retorts, and they are again filled with
inert gas, and this is again pumped out until as nearly as possible all the ammonia
is expelled.
The retorts and contents are now heated to the temperature requisite for
obtaining chlorine, which in the case of protoxide of nickel is between 500 degrees
and 550 degrees centigrade. A slow current of air previously carefully dried by
means of sulphuric acid or chloride of calcium, and preferably heated in an ordinary
air-heating apparatus to about 500 degrees Centigrade, is now passed through the
retorts, which are as nearly as possible kept at the same temperature. Previously
to admitting the air, the valves in the conduits leading from the retorts to the
ammonia absorbing plant are shut, and another set of valves opened, which lead to
the apparatus in which the chlorine is to be utilized. If the current of air is
carefully regulated, a gas is obtained containing from 5 to 7 volumes, per cent of
chlorine.
This gas can be utilized for all purposes where chlorine is used now. When it
is desired to manufacture bleaching powder, this gas, after being cooled in cast iron
pipes is brought into contact with hydrate of lime, in a convenient apparatus, as,
for instance, a Deacon bleaching powder chamber.
C
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;
1st The process of obtaining ammonia and chlorine from solid ammonium
chloride, which consists in vaporising the ammonium chloride, passing the vapours
at an elevated temperature over or through protoxide of nickel, or one or several
of the oxides of cobalt, magnesium, zinc, copper, iron, manganese, aluminium,
bismuth, or other heavy metals, possessing similar chemical properties to those
named, loosely piled in a closed chamber or retort, made of or lined with materials
refractory to the chemicals employed, collecting the ammonia thereby separated,
passing a neutral gas (such as described) through the chamber or retort to drive
out the residual ammonia, then passing through the chamber or retort still
containing the solid materials previously acted on, and maintained at a suitable
temperature dry air, preferably heated to such a temperature as to supply as far as
possible the heat required for carrying on the reactions, and for making up the loss
by radiation and other causes, hereby obtaining a mixture of gas composed of
chlorine, oxygen, and nitrogen, which can be utilized in the manufacture of
bleaching powder, or otherwise. Lastly, if the oxide used has been converted
by the passage of air, into a higher oxide, passing a reducing gas such as producer
gas over the residue, and then beginning the cycle of operations afresh.
2nd The process of obtaining ammonia and chlorine from ammouium chloride,
which consists in bringing the vapour of the ammonium chloride in contact with
protoxide of nickel, or one or several of the oxides of cobalt, magnesium, zinc,
copper, iron, manganese, aluminium, bismuth, or other heavy metals, possessing
similar chemical properties to those named, at an elevated temperature, till the
oxide is sufficiently chloridised, and then passing in air, at a suitable temperature
to obtain chlorine.
3rd The improvements in the process of obtaining ammonia from ammonium
chloride, which consists in passing the vapour of ammonium chloride at an elevated
temperature, over or through the hercin before mentioned residual oxides from the
oxidising operation so as to obtain ammonia.
4th The improvement in the process of obtaining ammonia from ammonium
chloride, which consists in forming protoxide of nickel, or one or several of the
oxides of cobalt, magnesium, zinc, copper, iron, manganese, aluminium, bismuth,
or other heavy metals possessing similar chemical properties to those named into

page_text: .
bricks, lumps, or balls, loosely piling them in a chamber, and bringing them
in contact with the ammonium chloride, at an elevated temperature such as
described.
5th The process of obtaining ammonia and chlorine successively, from ammonium
chloride which consists in passing successively vapour of ammonium chloride, a
neutral gas, and air preferably previously dried and heated, through one and the
same retort or chamber, containing protoxide of nickel, or one or several of the
oxides of cobalt, magnesium, zinc, copper, iron, manganese, aluminium, bismuth, or
other heavy metals, possessing similar chemical properties to those named, loosely
piled, and repeating the process continuously so as to use the same solid materials,
continuously, without handling or moving them in any way.
6th The improvement in the process of obtaining ammonia and chlorine
successively from ammonium chloride, which consists in passing the vapour of
ammonium chloride, through a vessel or chamber containing protoxide of nickel,
or one or several of the oxides of cobalt, magnesium, zinc, copper, iron, manganese,
aluminium, bismuth, or other heavy metals possessing similar chemical properties
to those named, and then driving out the residual ammonia by means of a neutral
gas, and collecting the same before blowing in air, whereby all the ammonia is
saved, instead of being partially wasted, as it would be if the air were admitted
instead of the neutral gas.
7th The improvement in obtaining chlorine from the ammonium chloride by
means of protoxide of nickel, or one or several of the oxides of cobalt, magnesium,
zinc, copper, iron, manganese, aluminium, bismuth, or other heavy metals, possessing
similar chemical properties to those named, which consists in treating the chlorides
or oxy-chlorides formed by the action of the vapour of ammonium chloride on the
oxides named, with air, previously heated to an elevated temperature, so as to
reduce as much as possible, the supply of heat through the walls of the apparatus
employed.
8th The improvement in the process of obtaining ammonia and chlorine from
the ammonium chloride which consists in passing a reducing gas, such as producer
gas over the residue from the oxidising operation if an oxide has been employed,
which is oxidised higher than desirable, such as oxides of iron or manganese,
before using it again for the first operation.
ليوم
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