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Citric acid as an additive for iron contamination in watts type bath
(-----) January 13, 2008
I have a bath that seems to have a serios iron contamination, because the anode bags are brown I found that the citric acid could help to alleviate this problem does anybody know something about it?DANIEL HERNANDEZ
PLATING SHOP - BUCARAMANGA, SANTANDER, COLOMBIA
First of two simultaneous responses -- January 16, 2008
I'm curious HOW you have found citric acid helps with iron contamination. If you use air agitation and the bath ph at 4.0, the iron will oxidize at a much quicker rate than a solution agitated bath, and a ph lower than 4.0. It would seem to me additions of citric acid would lower the ph, thereby making it more difficult to precipitate iron. I'm sure your nickel supplier has a complexing agent for the bath, or can instruct you with a high ph batch treatment and proper filtering.
Process Engineer - Syracuse, New York
Second of two simultaneous responses -- January 16, 2008
Short term the Citric acid may help. Long term Citric acid will.
1) Cause Fungus on the bath.
2) Tie up so much iron that it can interfere with the function of the bath constituents.
Long term its much safer and better in terms of product quality that you consider:
1) Preventing iron contamination by blocking the source of contamination, after identifying the source.
2) Treating the bath periodically with Hydrogen peroxide at a pH of 5.5 - 6 and removing the precipitated sludge via a good filter of by settlement and decantation. Carbon is used in this treatment @ 1 to 3 gms per liter to clean up the oxidised organics the peroxide destroys.
The Peroxide is dosed @ 0.5 to 1.5 mls per liter.
The treatment is done @ 60 centigrade all through 3 to 4 hours that it takes.
A test in the lab prior to treating the bath will establish the dosage more accurately than I have stated.,.
Asif Nurie [dec.]
- New Delhi, India
With deep regret we sadly advise that Asif passed away on Jan 24, 2016
First of two simultaneous responses -- January 18, 2008
I guess you ask of citrates in the bath rather than citric acid, because citric acid could decrease the pH. Sometimes suppliers recommend citrates or tartrates. In fact it can hepls but you should remmember that they increase TOC in the nickel bath. In decorative nickel plating I don't recommend. It is easier to prevent or clean the bath acc. to Mr. Asif Nurie's advice.
- Warsaw, Poland
Second of two simultaneous responses -- January 18, 2008
citric acid in small quanities will help to complex iron contamination so it will not disturb your nickel deposition. But it won't help to eliminate it in higher concentration. To eliminate iron I fully support the recommendation of Mark. Also check what's the real source of this contamination.
- Mexico City, Mexico
January 28, 2008
Thanks a lot
I will take Mr Asif advice it look like the source of contamination was the nickel
- Bucaramanga, Santander, Colombia