feacetech - 29-3-2015 at 12:47
Will this test work with Liquid Aluminium Aulphate (Alum)?
Some background below.
I ask this as I suspect Nitric acid contamination in some Alum I have.
pH should be 2.4, however it is 0.83.
The SG is 1.324
The Sulphuric acid used to make the Alum fails the reducing test so it is not ultra pure.
Iron in the suspect Alum is 24.1 ppm.
Al2O3 is on the low side 7.89 ppm.
I suspect the Nitric acid may have come from the tanker carting the Alum. However I need to prove this either way.
There may not be a great deal of Nitric in the sample so dilution of the alum may not work.
Concerns: 1. the SG of the Alum is too high, 2. the sulphuric content of the alum may interfere with the test. 3. The impurities in the acid may
interfere.
3. can be alleviated with a control sample of Alum
Thank you.
[Edited on 29-3-2015 by feacetech]
feacetech - 29-3-2015 at 17:06
I'm guessing it will be fine, I will try this test once I get some iron sulphate
unless anyone has a better test
Oscilllator - 30-3-2015 at 02:34
If that doesn't work, you can always try boiling a concentrated solution of your alum along with some copper turnings.
feacetech - 1-4-2015 at 15:10
Worked fine with a positive control, after a while an alum ppt will form at the liquid interface.
One of the positive controls had a very strong reaction and some sort of pink/red compound started to leach into the heavier H2SO4 phase, it looked
like KMnO4 (but we no it wasn't).
My iron sulphate was mono hydrate and fert grade.
long story short qualitatively there was no detectable nitric acid in my low pH alum. +ve and -ve controls worked
[Edited on 1-4-2015 by feacetech]