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Chlorine dioxide hazardous substance data sheet
(The text is based on the hazardous substances data sheet issued by the
Bundesvereinigung der Firmen im Gas- und Wasserfach e.V. FIGWA,
50968 Cologne, dated 16.4.1998.)
The chlorine dioxide solutions used for water treatment have a concentra‐
tion of ≤ 2 g/L ClO
2
. At a temperature of up to 25 degrees C, this results in
a chlorine dioxide concentration in the gas chamber of less than 100 g/m
3
.
Consequently, if preparation is carried out correctly, this will rule out explo‐
sive decomposition in both the gas chamber and in the stock solution.
25.1 Physical and chemical properties
25.1.1 Chemical characterisation
Aqueous solution of chlorine dioxide (ClO
2
) ≤ 2 g ClO
2
/L of physically dis‐
solved chlorine dioxide gas
25.1.2 Properties of gaseous chlorine dioxide
Orange-yellow
Pungent
- 59 ºC
11 ºC
Gaseous chlorine dioxide explosively decomposes at concentrations
above 300 g/m
3
(≅10 % by volume) into chlorine and oxygen.
Dilution reduces the explosive tendency; there is no longer a risk of explo‐
sion at concentrations below 10 % by volume in gases with which chlorine
dioxide does not react (e.g. with air, nitrogen, carbon dioxide).
A concentration of more than 8 g/L of chlorine dioxide (at a temperature of
20 degrees C) has to be be reckoned with, for instance with a critical
chlorine dioxide concentration in the gas chamber above an aqueous
chlorine dioxide solution.
A severe to explosive-type reaction likewise occurs with oxidising sub‐
stances.
25.1.3 Properties of an aqueous solution of chlorine dioxide
The gaseous phase is decisive.
Without an upper gas compartment, aqueous chlorine dioxide solutions
are explosive from a concentration of around 30 g/L, i.e. they can autono‐
mously explosively decompose without any external influences, such as
heat, sparks, dirt or rust.
Chlorine dioxide is stable over several days as an aqueous dilute solution,
provided the solution is pure and stored in the dark or if the temperature of
the solution remains below 25 degrees C and its pH value is less than 7.
Properties of chlorine dioxide and instruc‐
tions for handling aqueous solutions
Colour:
Odour:
Melting point:
Boiling point:
Stability:
Stability:
Chlorine dioxide hazardous substance data sheet
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