Improvements in Obtaining Ammonia, Chlorine, and Hydrochloric Acid from Ammonium Chloride.
Year: 1892

page_text: Date of Application, 3rd Nov., 1892
Complete Specification Left, 3rd Aug., 1893-Accepted, 9th Sept., 1893
PROVISIONAL SPECIFICATION.
Improvements in Obtaining Ammonia, Chlorine, and Hydrochloric
Acid from Ammonium Chloride.
I, LUDWIG MOND of Winnington Hall, Northwich in the County of Chester,
Manufacturing Chemist, do hereby declare the nature of this invention to be as
follows:-
In previous Patents, numbered and dated 66, 1049 and 3238 all of 1886,
10,955 of 1887 and 2575 of 1889 respectively, I have described new processes for
obtaining ammonia and chlorine from ammonium chloride and have set forth the
manner of carrying these processes into practice.
These processes consist in the treatment at a suitable temperature of certain
oxides or salts fully specified in my above mentioned Specifications, by ammonium
chloride, by preference previously vapourised, which gives rise to the formation of
fixed chlorides and oxy-chlorides, and liberates ammonia gas and vapour of water;
and subsequently the treatment with air of the fixed chlorides or oxy-chlorides so
obtained, at a more elevated temperature than the one employed during the
previous operation, whereby chlorine gas is obtained and the oxide or salt originally
employed is regenerated. In order to avoid loss of ammonia and to more easily
effect the change of temperature required, the chlorides or oxy-chlorides formed
in the first operation are subjected to a current of hot inert gas before the
treatment with air commences, as I have also fully set forth in my previous
Specifications.
The ammonia gas obtained in the first operation sometimes contains a small
quantity of chloride of ammonium vapour, which is apt to block the conduits
through which this gas passes. I therefore propose to place a washer or series of
washers in close proximity to the apparatus in which the ammonia gas is evolved
and connected to this by a pipe covered with a non-conducting material, so as to
avoid condensation of chloride of ammonium in this short pipe, and to treat the
ammonia gas in this washer with hot milk of lime, which condenses and completely
decomposes the chloride of ammonium vapour, forming calcium chloride and
liberating ammonia, without absorbing any quantity of the latter; or to treat the
gas in this washer with very hot water or an unsaturated solution of ammonium
chloride which absorbs the ammonium chloride vapour and only very little caustic
ammonia. Using the same hot water or unsaturated solution of ammonium chloride
over and over again it is possible to obtain gradually a concentrated solution of
ammonium chloride.
The inert gas mentioned above also contains besides ammonia, some ammonium
chloride vapour, and at a later stage it contains a small quantity of hydrochloric
acid gas.
To remove these, I pass the inert gas through the same washer or
washers which serves for washing the ammonia gas, and wash it there with hot
milk of lime or with hot water or a hot unconcentrated solution of ammonium
chloride containing a little ammonia, which removes the bulk of the ammonium
chloride and also the hydrochloric acid, and then through another washer or series
of washers to absorb the caustic ammonia by means of cold water or brine. On
leaving these, the inert gas, however, still contains a small quantity of ammonium
chloride in an extremely fine state of division, and in order to recover this, I pass
the gas through a layer of cotton wool or other fibrous material (such as siag
wool, etcetera) possessing the quality of filtering very fine solid particles out of
a gas.
In order to economise the inert gas used in the process and to obtain it as free

page_text: as possible from deleterious ingredients, I propose to use the same inert gas after
it has been treated as just described, over and over again. The chlorine gas
obtained in the second operation frequently contains small quantities of hydro-
chloric acid gas. To eliminate and to recover this hydrochloric acid, I propose to
wash the chlorine gas with a concentrated solution of chloride of calcium which
only absorbs traces of chlorine and completely retains the hydrochloric acid. By
subsequently heating the chloride of calcium solution containing hydrochloric acid,
the latter is given off as dry or almost dry hydrochloric acid gas, which can be
condensed by water to obtain commercial hydrochloric acid, or which may be
directly treated for the manufacture of chlorine. For the latter purpose, I prefer
to send it directly into the apparatus in which I treat the oxides or salts
previously mentioned with ammonium chloride vapour.
The chloride of calcium solution, after being cooled, can be used again for
washing the chlorine gas.
Dated this 2nd day of November 1892
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Patent Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Obtaining Ammonia, Chlorine, and Hydrochloric
Acid from Ammonium Chloride.
"
I, LUDWIG MOND of Winnington Hall, Northwich in the County of Chester
Manufacturing 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 :-
In previous Patents, numbered and dated 66, 1049 and 3238 all of 1886, 10,955
of 1887 and 2575 of 1889 respectively,.I have described new processes for obtaining
ammonia and chlorine from ammonium chloride and have set forth the manner of
carrying these processes into practice.
These processes consist in the treatment at a suitable temperature of certain
oxides or salts, fully specified in my above mentioned Specifications, by ammonium
chloride, by preference previously vapourised, which gives rise to the formation of
fixed chlorides and oxychlorides, and liberates ammonia gas and vapour of water;"
and subsequently the treatment with air of the fixed chlorides or oxy-chlorides so
obtained at a more elevated temperature than the one employed during the
previous operation, whereby chlorine gas is obtained and the oxide or salt originally
employed is regenerated. In order to avoid loss of ammonia and to more easily
effect the change of temperature required, the chlorides or oxy-chlorides formed
in the first operation are subjected to a current of hot inert gas before the
treatment with air commences, as I have also fully set forth in my previous
Specifications.
The ammonia gas obtained in the first operation sometimes contains a small
quantity of chloride of ammonium vapour, which is apt to block the conduits
through which this gas passes. I therefore propose to place a washer or series of
washers in close proximity to the apparatus in which the ammonia gas is evolved,
and connected to this by a pipe covered with a non-conducting material, so as to
avoid condensation of chloride of ammonium in this short pipe, and to treat the
ammonia gas in this washer with hot milk of lime, which condenses and completely
decomposes the chloride of ammonium vapour, forming calcium chloride and
liberating ammonia, without absorbing any notable quantity of the latter; or to
treat the gas in this washer with very hot water or an unsaturated solution of
ammonium chloride which absorbs the ammonium chloride vapour and only very
little caustic ammonia. Using the same hot water or hot unsaturated solution of
ammonium chloride over and over again, it is possible to obtain gradually a

page_text: No text detected.

page_text: chloride of calcium, in order to free it from hydrochloric acid and to recover the
same.
Dated this 2nd day of August 1893.
WM. P. THOMPSON & Co.,
Of Liverpool, Manchester, Nottingham, and London, Patent Agents.