Non-chromated De-oxidizer 1

[QualitymanPMF]

Our company uses an in-house mixed Non-chromated De-oxidizer. The percentages are fairly simple but duplicating the formula for the initial charge is posing a problem. The person who created the mix in the first place has retired and left for places unknown.
It is:
H2SO4 5-10%
HNO3 5-10%
FeSO4 15-25%
The trick is to match the total acid to the total ferrous at around 10%-20% any one have an idea on the quantities required to make up a 2000 gallon bath?
8 gal H2SO4
8 gal HNO3
20 lbs FeSO4
seems to be the suggested amounts.

 

[nbucska]

if you have a sample, analyze it. Determine the quantity
of SO4, Fe,NO3 and calculate the rest

If you don't have, what are you using it for and under
what circumstances ?




Plesae read FAQ240-1032
WEB: <

http://geocities.com/nbucska/>

 

[QualitymanPMF]

This is used to Deoxidize and de-smut aluminum before sulfuric acid anodize.
We have a sample of it the testing procedure is:

Check Ferrous Sulfate:
In a 200 ml beaker add:
5 ml sample
60 ml RO water
30-40 drops Indicator 20 (Sulfosalicylic Acid)
Use (N10 Versane) and titrate until color turns yellow
Equation: Solution ml * 1.6 = % by volume

To check Total acid:
In a 200 ml beaker add:
10 ml sample working solution
100 ml RO Water
Use NAOH 1N and titrate until a pH of 8.0 – 9.0.
Equation: Number of mils NAOH X 1.6 = Total acid by volume

This gives total acid (A combination of H2SO4 and NHO3) And total Ferrous. These should balance at equal % (10% of each is Best).

The tricky part is that two components are liquid and one is powder (Ferrous Sulfate) and that some of sulfate in the Ferrous Sulfate breaks down into H2SO4 when added to the water.

Any help or insight into these materials would be greatly appreciated.

 

[nbucska]

if you have a sample of the de-oxydizer solution,
analyze it.

There is no trick, the FeSO4 is usually crystallizes
in the form of heptahydrate (FeSO4+7H2O ) but you don't
care: determine the amount of Fe needed. Make a close to
saturated FeSO4 solution - determine the Fe per volume
unit and calculate the volume you have to add.

or
Use the sample es etalon and set up the same FeSO4
concentration by comparing the color using a colorimeter.



Plesae read FAQ240-1032
WEB: <

http://geocities.com/nbucska/>

 

[QualitymanPMF]

Thank you that really helped. I came up with the proportions in the first posting by doing just that adding Ferrous Sulfate to solution until I got the 10% then added the sulfuric and nitric acid in equal portions to achieve 10% total acid. I just wanted to know if this was a correct method and you confirmed it. Thank you