14
V
apodest
10
s
6.3. Results too low or no results
Cause of failure and correction
No quantitative carry over of the ammonia content, the
amount of the distillate should be 100ml.
- Contaminated or detective viton cone; clean or
replace.
- Check seals at the distribution head and if neces-
sary, replace it.
- Non return valve at the condenser is bonded, clean
or replace it.
- Digestion tube is damaged at the wide neck ope-
ning.
- Glass of the distribution head is leaking, replace
it!
Check the amount delivered by the NaOH pump; about
4 ml should be delivered per second.
Increase of the amount of boric acid.
Increase of the amount of acid.
This problem only occurs with catalysts containing
mercury, sodium thiosulphate solution destroys these
complexes.
Error description
Distillation has not been complete or distillation time
has been too short.
Ammonia escapes at leaks.
Amount of caustic soda which is added is too low, no
release of ammonia.
Not enough boric acid in the receiver, escaping ammo-
nia is not entirely absorbed.
Tube is not immersed entirely into the boric acid recei-
ver.
Formation of ammonia complexes which are not de
-
stroyed by the caustic soda.
6 Errors
