Year: 1886

page_text: I LUDWIG MOND of 20 Avenue Road, St. John's Wood, London, Manufacturing
Chemist, do hereby declare the nature of this invention to be as follows:-
This invention has for its object the obtaining of Chlorine from gaseous Hydrochloric
Acid by substantially the same process as that which I have lately introduced for
obtaining Chlorine from Ammonium Chloride.
The Hydrochloric Acid gas is brought into contact at an elevated temperature with
Protoxyde of Nickel or some other of the Oxides or salts hereinafter specified or sub-
stances containing the same; the chlorine combines with the base, & vapour of water
is given off. The oxide, oxychloride, or composite salt thus formed is subsequently
exposed at a suitable temperature to Oxygen or air, by which means the original
oxide or salt is again obtained, and chlorine given off. This can be used in making
bleaching powder, or for other purposes.
I prefer to carry out the two subsequent operations involved in the process in one.
single apparatus in which the substances used always remain untouched, and to pass.
through this apparatus, kept at a suitable temperature, and into intimate contact with
the substance used, a current of Hydrochloric Acid gas, next a current of air, then a
current of Hydrochloric Acid gas, & so on.
The air employed I prefer to be carefully dried & heated beforehand.
The processes previously proposed for obtaining Chlorine direct from Hydrochloric
Acid gas, such as the well known Deacon process, convert the Hydrochloric Acid gas
only partially into Chlorine. The principal aim of my process is the complete con-
version of the Hydrochloric Acid into Chlorine, & also the treatment of impure
Hydrochloric Acid gas which is unfit to be employed in the Deacon process. because
it is too Dilute or because it is mixed with deleterious gases (for instance Carbonic
Acid) such as is obtained in the manufacture of Sulphate of Soda by the Hargreaves
process, or from the roasters in the manufacture of Sulphate of Soda in the ordinary
way, or in Solvay's process for obtaining Hydrochloric Acid from Chloride of Calciuni.
For the complete conversion of the Hydrochloric Acid in such gases into useful Chlorine
only a certain number of the Oxides and Salts which can be employed for obtaining
Chlorine from Chloride of Ammonium, are applicable, & more especially the oxides &
гр.

page_text: Salts of those metals which only form one Oxide, such as Magnesium, Zinc,
Aluminium, &c., or of those metals which at the elevated temperature employed form
in a current of air their monoxide (R.O) only, such as Nickel, Cobalt &c. These
metals which at an elevated temperature form in contact with air higher oxides, as,
for instance, Manganese & Iron, give rise when these higher Oxides are treated with
Hydrochloric Acid gas, to the formation of Chlorine which remains mixed with the
impurities in Hydrochloric Acid gas, and can therefore not be utilized in any way,
and would be a source of loss and great trouble."
This difficulty can be overcome by passing over the higher oxide previous to
treating it with Hydrochloric Acid, a current of a reducing gas, such as Hydrogen,
or the gas obtained from gas producers which converts the higher oxide into a
monoxide.
The salts which can be used for this process are particularly the neutral salts of the
oxides named with the polybasic acids stable at high temperatures such as Silicic,
Phosphoric and Boracic acid, and also the Silicates of Lime.
The Chlorine and Oxygen successively combine with one or more atoms of the base,
using it in fact as a metallic oxide, the polybasic acid appearing to act as an assistant
without alteration.
The best results are however obtained with Oxide of Nickel or Cobalt, because with
these oxides the Chlorine can easily be obtained quite free from Hydrochloric Acid,
while with most others the Chlorine is contaminated with a small quantity of Hydro-
chloric Acid, which necessitates careful washing and subsequent drying of the Chlorine
gas before it can be applied to the manufacture of bleaching powder & because with
these Oxides it is possible to carry on the two operations constituting the process at
nearly the same temperature (about 500° F) and without any loss of the material
ised, as the Chlorides of Nickel and Cobalt are not at all volatile at this temperature.
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 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 or Salt 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. A con-
venient apparatus for carrying this process into practice consists of retorts or
cylinders made of carthenware or of cast iron which latter may be preferably
enamelled or lined with fire-proof acid-resisting materials such as fire-bricks gannister
&c. I prefer to heat the Hydrochloric Acid gas & the Air before entering these
cylinders or retorts so as to reduce as far as possible the amount of heat which
has to be passed through their walls. I am thus enabled to make the cylinders of
large diameter and simple construction.
Dated this 23rd day of June 1886.

page_text: I, LUDWIG MOND of 20 Avonue Road St. John's Wood, London 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:-
This invention has for its object the obtaining of chlorine from gaseous hydrochloric
acid by substantially the same process as that which I have lately introduced for
obtaining clilorine from ammonium chloride.
The hydrochloric acid gas is brought into contact at an elevated temperature with
protoxide of nickel or some other of the oxides or salts hereinafter specified, or
substances containing the same, the chlorine combines with the base, and vapour of
water is given off. The oxide, oxychloride, or composite salt thus formed is subse-
quently exposed at a suitable temperature to oxygen or air, by which means the
original oxide or salt is again obtained, and chlorine given off. This can be used in
making bleaching powder, or for other purposes.
I prefer to carry out the two subsequent operations involved in the process in one
single apparatusan which the substances used always remain untouched, and to pass
through this apparatus, kept at a suitable temperature, and into intimate contact with
the substance used, a current of hydrochloric acid gas, next a current of air, then a
current of hydrochloric acid gas, and so on. The air employed, I prefer to be carefully
dried and heated beforehand.
The process previously proposed for, obtaining chlorine direct from hydrochloric
acid gas, such as the well known Deacon process, converts the hydrochloric acid gas
only partially into chlorine. The principal aim of my process is the complete con-
version of the hydrochloric acid into chlorine, and also the treatment of impure hydro-
chloric acid gas which is unfit to be employed in the Deacon process because it is too
dilute, or because it is mixed with deleterious gases, (for instance carbonic acid) such
as is obtained in the manufacture of Sulphate of Soda by the Hargreaves process, or
from the roasters in the manufacture of sulphate of soda in the ordinary way, or in
Solvay's process for obtaining hydrochloric acid from chloride of calcium. For the
complete conversion of the hydrochloric acid in such gases into useful chlorine only a
certain number of the oxides and salts which can be employed for obtaining chlorine
from chloride of ammonium, are applicable, and more especially the oxides and salts
of those metals which only form one oxide, each, as magnesium, zinc, aluminium,
etcetera, or of those metals which at the elevated temperature employed form in a
current of air their monoxide (R.O.) only, such as nickel, cobalt, etcetera. Those
metals which at an elevated temperature form in contact with air higher oxides, as, for
instance, manganese, and iron, give rise when these higher oxides are treated with
hydrochloric acid gas, to the formation of chlorine which remains mixed with the
impurities in hydrochloric acid gas, and can therefore not be utilized in any way, and
would be a source of loss and great trouble.
This difficulty can be overcome by passing over the higher oxide previous to treating
it with hydrochloric acid, a current of a reducing gas, such as hydrogen, or the gas
obtained from gas producers, which converts the higher oxide into a monoxide.
The salts which can be used for this process are particularly the neutral salts of the
oxides named with the polybasic acids stable at high temperatures, such as silicic,
phosphoric and boracic acid, and also the silicates of lime.

page_text: The chlorine and oxygen successively combine with one or more atoms of the base,
using it in fact as a metallic oxide, the polybasic acid appearing to act as an assistant
without alteration.
The best results are however obtained with oxide of nickel or cobalt, because with
these oxides the chlorine can easily be obtained quite free from hydrochloric acid,
while with most others the chlorine is contaminated with a small quantity of hydro-
chloric acid, which necessitates careful washing and subsequent drying of the chlorine
gas before it can be applied to the manufacture of bleaching powder, and because with
these oxides it is possible, to carry on the two operations constituting the process at
nearly the same temperature (about 500 degrees Celsius) and without any loss of the
material used, as the chlorides of nickel and cobalt are not at all volatile at this
temperature.
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 metal to be
cmployed, and after drying, to heat the same in a current of air so as to produce the
oxide, or the oxide or salt 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 subse-
quently drying and heating in a current of air or otherwise. A convenient apparatus
for carrying this process into practice consists of retorts or cylinders made of earthen-
ware or of cast iron which latter may be preferably enamelled or lined with fire-proof,
acid resisting materials such as fire-bricks, gannister, etcetera. I prefer to heat the
hydrochloric acid gas, and the air before entering these cylinders or retorts, so as to
reduce as far as possible the amount of heat which has to be passed through their walls.
I am thus enabled to make the cylinders of large diameter, and simple construction.
"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 manufacture of chlorine from hydrochloric acid by passing its vapour and
air alternately (both preferably heated) through a chamber or retort partially filled
with loosely piled oxide or salt such as herein set forth.
2nd. In the manufacture of chlorine from hydrochloric acid, the use of oxide of
nickel or of cobalt at an elevated temperature for decomposing the HCl, substantially
as described.
3rd: In the manufacture of chlorine from hydrochloric acid by passing the latter
alternately with air over suitable salt or oxide, heating the said air and hydrochloric
acid sufficiently to maintain the heat in the reaction chamber to a sufficient degree to
carry on the reactions, without the aid of external heating, whereby a simpler and
larger chamber can be used than would otherwise be practicable.
4th. In the manufacture of chlorine from hydrochloric acid by passing the latter
and air alternately over suitable salt or oxide, heated to the requisite temperature,
drying the air used before passing it into the reaction chamber, whereby the re-formation
of hydrochloric acid 'from a part of the chlorine is prevented.
5th. In the manufacture of, chlorine from hydrochloric acid with the aid of an oxide
of a metal which at the temperature used, would in contact with air, form a higher
oxide passing a current of a reducing gas over the same before admitting the HCl.
1. 1007
WM. P. THOMPSON & Co.,
Of G, Lord Street, Liverpool,
Agents for the Applicant.