Letter 14083

Help cleaning stainless steel tanks  

We have about 50 stainless steel tanks that have been used for years in mixing dyestuffs and chemicals. There is a buildup of unknown substance, probably emulsifiers fro silicone defoamer chemicals, but it is not water soluble, nor soluble in most solvents. It is difficult to get access to the tanks due to all the OSHA requirements, so putting someone down in the 48 inch diameter, 96 inch deep tanks is difficult. I am considering removing them one at a time, and replacing with one new tank, then trying to see who can clean the tanks off site. I am not sure if sandblasting is an option, or whether it will pit the tanks hopelessly. I need to have them reurned with a high polish finish. Firstly what are the most practical cleaning options, and secondly, once cleaned, is there any product that could be sprayed onto the tank sides, to resist, mainly water based dye solutions containing acid and wetters at a pH of about 2-6 ??

Geoff Boyes
- Rocky Mt, VA, USA

DO NOT sand blast or otherwise roughen the surface. You'll never get it smooth again. If you can't remove the coating with any solvent, what is it harming? Ask you chemicals supplier to give you the different solvents that work with his product. Then you can ask a stainless expert if it's safe for the tank. Coatings like PTFE can be put on stainless to make them cleanable.

Dr. Michael McGuire
- Pittsburgh, PA, USA

Geoff:

I think sodium bicarb wet blasting followed by interior electropolishing is your best bet. Our plant in N.E. Georgia is equipped to handle tanks this size.

Dan Weaver
Team Metal Finishing , Inc. - Toccoa, GA

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