Danger working with the ika, C 6000 global standards/isoperibol calorimeter – IKA C 6000 isoperibol Package 2/12 User Manual

Page 24

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24

Note on the sample
The calorimeter system IKA

®

C 6000 global stan-

dards/isoperibol is a precision measuring instru-
ment for the routine determination of calorifi c
values of solid and liquid substances. Exact mea-
surements can however be achieved only if the
individual steps of the trial are performed with
care. The procedure as described in the „For your
safety“ section and in the following sections must
therefore be adhered to exactly.

If you are burning unknown

samples, leave the room or

keep well away from the ca-

lorimeter.!

A few points should be noted in respect of the
substances to be combusted:

• Normally, solid substances can be burned direct-
ly in powder form. Rapidly burning substances (for
example benzoic acid) must not undergo combus-
tion in loose form.
Benzoic acid must only be burned in the form
of pellets! Combustible dust and powder must
be compressed into pellets before combustion.
Oven-dry dust and powder such as wood chips,
hay, straw etc. burn in an explosive manner! They
must be moistened fi rst! Readily combustible li-
quids with a low vapor pressure must not be come
in direct contact with the cotton thread (e.g. tet-
ramethyl dihydrogen disiloxan).

Rapidly burning substances tend to squirt. Such

substances must be pressed into tablets be-

fore combustion. Suitable for this is e.g. the

IKA

®

-pelleting press C 21, see „Accessories“.

• Most liquid substances can be weighed direct-

ly into the crucible. Liquid substances exhibiting
turbidity or containing water that will settle out
must be dried or homogenized before they are
weighed in. The water content of these samples
must be determined.

• Highly volatile substances are placed in combus-

tion capsules (gelatin capsules or acetobutyrate
capsules, see „Accessories“) and undergo com-
bustion together with the capsules.

• For substances with low fl ammability or low

calorifi c substances use combustion aids (see
„Accessories“). Before the capsules or the com-
bustion bag is fi lled with the substance to be
determined, it must be weighed in order to de-
termine the additional extraneous energy intro-
duced into the system from the weight and the
gross calorifi c value. This is taken into considera-
tion with QExtern2. The amount of combustion
aid should be as little as possible.

• Under the conditions that prevail during calori-

metric measurements, sulfur and nitrogen un-
dergo combustion and form SO

2

, SO

3

and NO

X

.

Sulfuric and nitric acid arise in combination with
the water resulting form combustion. Heat of
solution is also generated. This heat of solution is
taken into consideration in calculating the gross
calorifi c value. In order to quantitatively record
and determine all acids that have been formed,
about 5 ml of distilled water or another suitable
substance can be added to the decomposition
vessel before the experiment.

The calibration of the system must have been

performed in accordance with the instructions!

After combustion, the water that was added, is
collected and the decomposition vessel is rinsed
throughly with distilled water. The rinsing water
and the solution formed from the water that was
added are combined and the acid content of the
combined solution is examined. If the sulfur con-
tent of the combustion aid and the nitric acid cor-
rection are known, the water does not need to be
analyzed.

To increase the service life of parts to wear

and tear (O rings, seals etc.) we recommend to

work with water added to the experiment as a

matter of general principle.

Caution! Risk of corrosion!

Substances with high halo-

gen content must not be combusted in the C
6010 decomposition vessel; instead use the
C 6012 decomposition vessel.

WARNING

DANGER

Working with the IKA

®

C 6000 global standards/isoperibol calorimeter

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