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Sulfuric Acid Anodizing Emission Calculations or Emission factors

I have been asked to calculate the emissions from the sulfuric acid tanks of an aluminum anodizing operation. Does anyone know of an emission equation or emission factor I can use for this type of process?

Kevin Dubart
Consultant - Miami, Florida
February 2, 2011

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There are a number of empirical formulas for calculating vapor emissions. But, you will soon realize that vapor vapor emissions are nil due to the extraordinarily low partial vapor pressure of sulfuric acid over aqueous solutions of sulfuric acid. For Type II, you'd be somewhere in the neighborhood of 0.8 x 10-18 mm Hg (Reference- Perry's ChE Handbook).

Instead, the emissions from anodizing are in the form of mists. Mists are formed as a result of gas evolution from the anodes and cathodes. When the gasses reach the surface of the solution, the bubbles pop and generate a mist. I do not believe that anyone has published an empirical formula for calculating mists from anodizing, but it should be possible to relate mists to rectifier output and the velocity of ventilation air above the surface. Maybe someone else can give more guidance, but when I used to do "engineering estimates" on sulfuric acid emissions for an EPA air operating permit, I was forced to lean heavily on the word "estimates" if you know what I mean. Good luck.

Jon Barrows, MSF, EHSSC
GOAD Company

Independence, Missouri

February 2, 2011

Thanks for the info. I am actually doing them for the same reason, air operating permit. The air division here couldn't provide one either.

Kevin DuBart
- Miami, Florida
February 7, 2011