Rinsing Sulfuric Acid

I have a problem after stripping with Sulfuric Acid residue. I am rinsing in three rinse tank of about 200 gallons and a hot water rinse of 250 gallons at 125 degrees with counter flow system and putting 3.0 gpm in the hot water rinise. is there any way to break down the acid residue with out using more water.

Anodizers frequently deal with their sulfuric acid residues either by dipping in very dilute nitric acid, which displaces the sulfuric acid, or by dipping in dilute sodium bicarbonate. These approaches are probably worth a bench test, approached with care due to the reactive nature of the ingredients.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey

Drag out less acid if possible. If not, try to add a mist rinse over the top of at least the first rinse tank after it comes out of the rinse. Do this on all three tanks and you have the effect of up to 6 rinse tanks at virtually no additional water flow.

I had the same problem and the way I fixed it was to rinse in a flowing rinse, then rinse in your desmut or deox then your rinses and you should be good.

I have to agree with Mr. Watts. We had a similar problem and we added cold water sprays to the rinses after the acid and it took the problem away, we run our's at 3.5 gpm.