Processes for the Production of Chlorine and of Obtaining Concentrated Gaseous Hydrochloric Acid for that Purpose..
Year: 1889

page_text: Date of Application, 31st Oct., 1889
Complete Specification Left. 26th Nov. 1889 Accepted 25th Jan 1890
PROVISIONAL SPECIFICATION.
Processes for the Production of Chlorine and of Obtaining
Concentrated Gaseous Hydrochloric Acid for that Purpose..
We, PROSPER DE WILDE, of Avenue Louise No. 345, Brussels, Professor of
Chemistry at the University of Brussels, and ALBERT REYCHLER of Rue de Suisse
No. 15 Brussels, Doctor of Science attached to the same University do hereby declare
the nature of this invention to be as follows:-
In a process for the preparation of hydrochloric acid and magnesia by means of
chloride of magnesium, for which one of us has obtained a French Patent
No. 185192,dated 20th May 1889, and has applied. for a German Patent W 6127 1/75
dated 20th May 1889, hydrochloric acid and a residue from a calcining process is
obtained, formed of an intimate mixture of sulphate of magnesium and of magnesia,
in the proportions of their chemical equivalents.
If the calcination is not carried to the end, the mixture also contains a certain
quantity of oxychloride of magnesium.
According to our present invention this mixture, which is of a solid porous
consistency, is placed, in fragments of the size of nuts, into a system of cylinders
of cast iron, or of earthenware, either glazed or not, and enclosed in a cast iron casing.
These cylinders are made to communicate with each other like the cylinders in the
sulphate process of Hargreaves:
When the temperature of a dark red heat is attained there is passed through the
enclosed mass in the cylinders, a current of hydrochloric gas, as concentrated as
possible. There is soon disengaged from the apparatus an abundant quantity of
steam, and the heated mass is transformed into a mixture of sulphate of magnesium,
chloride, and oxychloride of magnesium.
When the hydrochloric acid begins to be insufficiently absorbed, the passage of
this gas is stopped, and there is passed through the cylinders a current of air heated
to a dull red heat which is caused first to pass through a roheating apparatus,
similar to those which are used for beating the blast for blast furnaces. There might
also be employed for this purpose regenerators similar to those used with the
Siemens and other furnaces, or the air might be heated in cast iron pipes arranged
in the same furnace by which the cylinders are heated.
The air in passing through the heated mass, decomposes the chloride and oxy-
chloride of magnesium and liberates the chlorine. By this means the mixture of
sulphate of magnesium and of magnesia is regenerated, and is ready again to be
acted upon by hydrochloric acid gas, to be followed by the action of hot air and so
on in succession, the operations being thus continuously carried on in the same
apparatus heated to a dull or very dull red.
The gases given off from the cylinders when the air is passing through consist
essentially of a mixture of nitrogen and a small quantity of oxygen, and from 20 to
25 volumes per cent. of chlorine. The latter may be used directly for the preparation
of the hypochlorites and the chlorates.
There may also be passed through the cylinders a mixture of air and 'hydro-
chloric acid such as that which is given off by the sulphate furnaces.
In this case the operation becomes continuous, but the gases which come from
the apparatus are less rich in chlorine and contain hydrochloric acid and steam which
have to be removed by known processes before using them for the preparation of
the hypochlorites and chlorates.
A still better result is obtained by replacing the preceding mixture by the mixture
obtained in calcining at a dull red heat in a muffle furnace, equivalent quantities of
sulphate of magnesium, chloride of magnesium, and chloride of manganese, all three
being hydrated.
་

page_text: The proportions used may vary between certain limits. The calcined matter is
formed by an intimate mixture of anhydrous sulphate of magnesium and of
manganite of magnesium (Mn, Mga O). This mixture which disengages chlorine
when treated with liquid hydrochloric acid forms the subject of a Belgian Patent
dated 20th July 1889 No. 87068, and of a German application for a patent dated
22nd July 1889 in the name of A. Reychler.
This mixture which is coherent and porous is placed in the system of cylinders
above referred, and is heated to a dull red heat.
A current of hydrochloric gas is passed through and a rich current of Chlorine is
given off according to the equation :
The chlorine thus obtained necessarily contains a good deal of water and an excess of
hydrochloric acid. In order to utilize it, it has to be deprived of these two bodies,
which is effected by well known processes.
After the action of the hydrochloric acid (which it is not necessary to carry right
to the end) there remains in the cylinders a mixture of anhydrous sulphate of
magnesium, chloride of magnesium and chloride of manganese.
If there is directed upon this mixture a current of air heated to a dull red heat
there is disengaged chlorine, and the mixture of sulphate of magnesium and
manganite of magnesium is reconstituted.
B. 3.Mg SO + 3 Mn Cl₂ + 3 Mg Cl₂ +·0,
3 Mg SO, + Muş Mga Оg + C₁₁₂.
The gases passing from the apparatus contain from 20 to 30 volumes per cent. of
Chlorine, and can be directly employed for the production of hypochlorites and
Chlorates.
'
After the action of the air, the mixture of sulphate of magnesium and manganite
of magnesium is again acted upon by gaseous hydrochloric acid, whereby the above
mentioned reaction is produced. The mixture is then again acted upon with heated
air, and so on, the operations being continuously repeated in the same apparatus at a
dull or very dull red heat.
There may also be passed through the cylinders a mixture of air and hydrochloric
acid such as passes from the sulphate furnace. Our mixture remains consistent and
the reaction gives a continuous current of chlorine mixed with nitrogen, oxygen,
steam, and an excess of hydrochloric acid. Before use, it is deprived of these two
bodies by well known means.
Instead of the mixture of sulphate of magnesium, chloride of magnesium and
Chloride of manganese, there may also be employed sulphate of magnesium with a
double proportion of chloride of manganese...
The residue of calcination is then composed of anhydrous sulphate of magnesium
and of intermediate oxide of manganese. In heating at a dull red heat alternately
with hydrochloric gas and with air chlorine, is obtained according to the following
reactions:

page_text: This process can also be rendered continuous when the residue of calcination is
treated simultaneously with air and gaseous hydrochloric acid at a dull red heat.
The same reactions take place when a mixture of chloride of manganese, and of
chloride of magnesium or chloride of manganese alone is used. The residue of
calcination is then manganite of magnesium, or intermediate oxide of manganese.
When treated at a dull red heat alternately with gaseous hydrochloric acid and with
air, chlorine is obtained.
Chloride of magnesium alone, chloride of manganese alone, or a mixture of the
two is liable to become melted at the very dull red heat at which the operation is
effected so that the treatment with gaseous hydrochloric acid must not he carried too
far in any part of the apparatus, without danger of the apparatus becoming
obstructed by the melted material. The presence of the sulphate of magnesium
completely avoids this danger and in addition facilitates the decomposing action of
the air.
The sulphates of the alkaline metallic earths (Barium, Calcium Strontium) the
phosphates, arseniates borates and the less fusible silicates of magnesia and of the
alkaline metallic earths, Alumina and the silicates of alumina sand, and all the not
easily fusible substances which by their presence do not interfere with the existence
of the free magnesia, the manganite of magnesium or the intermediate oxide of
manganese can be made use of under these circumstances.
The gaseous hydrochloric acid which we use alternatively with the air should be as
concentrated as possible.
It is taken out of the pan of a sulphate furnace, or prepared by treating the
commercial solution of hydrochloric acid by means of sulphuric acid of 60 Bº. The
two acids are simultaneously introduced in determined quantities through several
conduits into the top of a lead column of a height of from three to four metres of
variable diameter, filled with fragments of coke.
At the contact of the two acids there is given off gaseous hydrochloric acid which
passes off through a conduit leading from the top of the column to the apparatus for
the production of chlorine.
The diluted sulphuric acid flows off at the bottom of the column through an over-
How pipe, and is brought back to a strength of 60 B by known means.
Dated this 31st day of October 1889.
ABEL & IMRAY,
Agents for the Applicants.
COMPLETE SPECIFICATION.
Processes for the Production of Chlorine and of Obtaining
Concentrated Gaseous Hydrochloric Acid for that Purpose.
We, PROSPER DE WILDE, of Avenue Louise No. 345, Brussels, Professor of
Chemistry at the University of Brussels, and ALBERT REYCHLER, of Rue de Suisse
No. 15 Brussels, Doctor of Science attached to the same University, do hereby
declare the nature of this invention and in what manner the same is to bo
performed, to be particularly described and ascertained in and by the following
statement:
In a process for the preparation or hydrochloric acid and magnesia by means of
chloride of magnesium, for which one of us has obtained a French Patent No. 185192
dated 20th May 1889, and has obtained a German Patent No. 50155 dated 21st May
1889, hydrochloric acid and a residue from a calcining process is obtained formed
of an intimate mixture of sulphate of magnesium and of magnesia, in the proportions
of the chemical equivalents.
If the calcination is not carried to the end, the mixture also contains a certain
quantity of oxychloride of magnesium.
According to our present invention this mixture which is of a solid porous con-
sistence, is placed, in fragments of the size of nuts, into..a system of cylinders of

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FAT GHIGH WA, grazed or not, and enclosed In a cast ΠΟΠ
casing:
These cylinders are made to communicate with each other like the cylinders in the
sulphate process of Hargreaves.
When the temperature of a dark red heat is attained, there is passed through the
enclosed mass in the cylinders, a current of hydrochloric acid gas, as concentrated as
possible. There is soon disengaged from the apparatus an abundant quantity of steam
and the heated mass is transformed into a mixture of sulphate of magnesium, chloride,
and oxychloride of magnesium.
F
When the hydrochloric acid begins to be insufficiently absorbed, the passage of
this gas is stopped and there is passed through the cylinders a current of air heated
to a dull red heat by its passage through a heating apparatus like 'those used for
heating the blast for blast furnaces. There might also be employed for this purpose'
regenerators similar to those used with the Siemens and other furnaces, or the air
might be heated in iron pipes arranged in the same furnace by which the cylinders
are heated.
The air in passing through the heated mass, decomposes the chloride and oxychloride
of magnesium and liberates the chlorine. By this means the mixture of sulphate of
magnesium and of magnesia is regenerated and is ready again to be acted upon by
hydrochloric acid gas, to be followed by the action of hot air, and so on in succession,
the operations being thus continuously carried on in the same apparatus heated' to a
dull or very dull red.
The gases given off from the cylinders when the air is passing through consist
essentially of a mixture of nitrogen and a small quantity of oxygen, and from 20 to
25 volumes per cent. of chlorine. The latter may be used directly for the preparation
of hypochlorites and chlorates.
There may also be passed through the cylinders, a mixture of air and hydrochloric
acid, such as that which is given off by sulphate 'furnaces. In this case the operation
becomes continuous, but the gases which come from the apparatus are less rich in
chlorine and contain hydrochloric acid and steam which have to be removed by known
processes before using them for the preparation of hypochlorites and chlorates.
A still better result is obtained by substituting for the preceding mixture the mixture
obtained in calcining at a dull red heat in a muffle furnace, equivalent quantities of
sulphate of magnesium, chloride of magnesium, and chloride of manganese, all three
being hydrated.
The proportions used may vary within certain limits. The calcined matter is
formed by an intimate mixture of anhydrous sulphate of magnesium and of
manganite of magnesium (Mn, Mg, O₂).
This mixture which disengages chlorine when treated with liquid hydrochloric
acid forms the subject of a Belgian Patent dated 20th July 1889 No. 87068,
and of a German application for a patent dated 22nd July 1889 in the name of
A. Reychler.
This mixture which is coherent and porous is placed in the system of cylinders
above referred to and is heated to a temperature a little below a dull red heat.
A current of hydrochloric acid gas is passed through and a rich current of Chlorine
is given off according to the equation :
The chlorine thus obtained necessarily contains a good deal of water and an excess
of hydrochloric acid. In order to utilize it, it has to be deprived of these two 5
bodies, which is effected by well known processes.
After the action of the hydrochloric acid (which it is not necessary to carry quite
to the end) there remains in the cylinders a mixture of anhydrous sulphate of
magnesium, chloride of magnesium and chloride of manganese.
If there is directed upon this mixture a current of dry air heated to a dull red 5

page_text: heat, chlorine is disengaged, and the mixture of sulphate of magnesium and manganite
of magnesium is reconstituted.
B. 3 Mg SO, + 3 Mn Cl. +
3 Mg Cl, + 0,
3 Mg SO, + Mn, Mg, 0, + C₁₁₂.
8
The gases passing from the apparatus contain from 16 to 27 volumes per cent. of
Chlorine, and can be directly employed for the production of hypochlorites and
chlorates.
After the action of the air, the mixture of sulphate of magnesium and manganite
of magnesium is again acted upon by gaseous hydrochloric acid, whereby the above
mentioned reaction is produced. The mixture is then again acted upon with heated
dry air, and so on, the operations being continuously repeated in the same apparatus
at a dull or very dull red heat.
There may also be passed through the cylinders a mixture of air and hydrochloric
acid such as passes from the sulphate furnace.
Our mixture remains consistent and the reaction gives a continuous current of
chlorine mixed with nitrogen, oxygen, steam and an excess of hydrochloric acid.
Before use, it is deprived of these two bodies by well known means.
Instead of the mixture of sulphate of magnesium, chloride of magnesium and
chloride of manganese, there may also be employed sulphate of magnesium with a
double proportion of chloride of manganese.
The residue of calcination is then composed of anhydrous sulphate of magnesium
and of intermediate oxide of manganese. In heating to a dull red heat alternately
with hydrochloric gas and with air, chlorine is obtained according to the following
reactions.
A. 3 Mg SO, + 2 Mn, C₁ +
= 3 Mg SO₁ + 6 Mn Cl₂ +
16 H C
8 H2O + Cl₁,
for the treatment with heated air.
This process can also be rendered continuous when the residue of calcination
is treated simultaneously with air and gaseous hydrochloric acid at a dull red
heat.
The same reactions take place when a mixture of chloride of manganese and of
chloride of magnesium or chloride of manganese alone is used. The residue of calci-
nation is then manganite of magnesium or intermediate oxide of manganese.
When treated at a dull red heat alternately with gaseous hydrochloric acid and
with air, chlorine is obtained.
Chloride of magnesium alone, chloride of manganese alone, or a mixture of the
two is liable to, become melted at the very dull red heat at which the, operation is
effected so that the treatment with gaseous hydrochloric acid must not be carried
too far in any part of the apparatus, otherwise there may be danger of the apparatus
becoming obstructed by the melted material. The presence of the sulphate of
magnesium completely avoids this danger and in addition facilitates the decomposing
action of the air.
The sulphates of the alkaline metallic earths (Barium, Calcium, Strontium), the
phosphates, arseniates, borates, and the less fusible silicates of magnesia and of the
alkaline metallic earths, alumina and the silicates of alumina, sand, and all the not
easily fusible substances which by their presence do not interfere with the existence
of the free magnesia, the manganite of magnesium or the intermediate oxide of
manganese can be made use of under these circumstances.

page_text: Many chlorides of metals, such as magnesium, copper, nickel &c. become decom-
posed liberating chlorine and forming metallic oxides when they are subjected to
the action of a current of dry air at a more or less intense red heat.
Investigations have been conducted in this direction and patents have been taken.
We have found that in all cases the addition to the chloride treated, of one or of
several equivalents of sulphate of magnesium or of other alkaline earth not only
lessens the fusibility of the mass producing chlorine, but it also greatly promotes
the decomposing action of the air, so that the reaction may be carried on at lower
temperatures, furnishing a gaseous mixture more rich in chlorine.
The gaseous hydrochloric acid which we use alternatively with the air should be as
concentrated as possible.
It is taken out of the pan of a sulphate furnace, or prepared by treating the com-
mercial solution of hydrochloric acid by means of sulphuric acid.of 60 B. The two
acids are simultaneously introduced in determined quantities through several conduits
nto the top of a lead column of a height of from three to four metres of variable
diameter filled with the fragments of coke.
At the contact of the two acids there is given off gaseous hydrochloric acid which
passes off through a conduit leading from the top of the column to the apparatus
for the production of chlorine.
The diluted sulphuric acid flows off at the bottom of the column through an over-
How pipe, and is brought back to a strength of 60 Be by known means.
Having now particularly described and ascertained the nature of this inven-
ion and in what manner the same is to be performed we declare that what we
laim is :-
1. (a) The transformation of the calcined mixture of sulphate of magnesium and
magnesia to a mixture of sulphate and of chloride and oxychloride of mag-
nesium by the action of hydrochloric acid gas at a dull red heat.
(b) The separation of chlorine from the mixture thus obtained by the action of
a current of dry air at a dull red heat, thus forming a residue of sulphate
of magnesium and magnesia.
(c) The reproduction of the mixture of sulphate and chloride of magnesium by
repeating the action of hydrochloric acid gas at a dull red heat on this residue.
2. (a) The action at a very low red heat of hydrochloric acid gas on a mixture
of sulphate and manganite of magnesium or sulphate of magnesium and
intermediate oxide of manganese, with liberation of chlorine and production
of a mixture of sulphate and chloride of manganese, or sulphate of mag-
nesium and chloride of manganese.
(b) The action at red heat of a current of heated dry air on the mixture thus
obtained, with liberation of chlorine and reproduction of the original
mixture of sulphate and manganite of magnesium or sulphate of magnesium
and intermediate oxide of manganese, the two actions (a) and (b) being
carried on in the same apparatus.
3. The alternative action at red heat of hydrochloric acid gas and of heated dry
ir on the manganite of magnesium alone or on the intermediate oxide of manganese
lone, by the processes set forth in the preceding claim 2, (a) and (b).
4. The continuous production of chlorine by simultaneous action at a dull red heat
f hydrochloric acid gas and of hot dry air on a mixture of sulphate of magnesium*
nd magnesia.
5. The continuous production of chlorine by the simultaneous action at a dull red
eat of hydrochloric acid gas and heated air on a mixture of sulphate and
anganite of magnesium or sulphate of magnesium and intermediate oxide of
anganese.
6. In the processes referred to in the preceding claims instead of the sulphate of
agnesium the substitution of the sulphate of an alkaline earth or of a not readily
isible phosphate, arseniate, borate or silicate of magnesia or of an alkaline earth, of
lumina or silicate of aluminium, of sand or generally of any substance not readily.

page_text: fusible, the presence of which is compatible with the existence at a dull red heat
of free magnesia, of manganite of magnesium or of the intermediate oxide of
manganese.
7. The addition of sulphate of magnesium or of sulphate of an alkaline earth to
chlorides of metals to promote their decomposition by dry air at high temperature
with liberation of chlorine.
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ABEL & IMRAY,
Agents for the Applicants.