The authoritative public forum
  for Metal Finishing since 1989
  

  -----

Handling sulfuric acid

Hi,
I want to make 50 - 75% sulfuric acid by diluting 95% acid in water. The temperature is bound to rise to may be 90 - 95C (I am guessing). Can I do this in a Polypropylene tank? If so, is there a special grade that works better? I need to pump this diluted acid and was thinking of using a peristaltic pump. Am I on the right track.

I have heard SS310 is good for handling diluted sulfuric acid, say 30%, at relatively high temperature like 80C+. Anyone has any experience or advise on that? This is not a theoretical question. I have an actual application for this too.

Thanks

Bala Nathan
process engineer - Chicago, Illinois
October 30, 2009

---

Hi, Bala. You or the operator should have Haz-Mat training and be wearing full protective gear before attempting to dilute this hazardous material.

How hot it will get depends on how fast you add it, of course, but if you add the acid slowly enough, yes, it is practical to do this dilution in a polypro tank. I would not use stainless steel. Good luck.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
October 30, 2009

---

I would check out buying a lower % of sulfuric acid. The initial add is a huge temp rise and safety in handling needs to be much higher. 98% requires very good protective equipment and safety devices as getting splashed with a little as a half pint will cause serious damage to the skin if you are not VERY near to a safety shower/eye wash. In seconds!
Consider the true cost of the acid versus cost of handling it.
To save labor time, I used to fill the tank with chipped ice and then add the acid. It still got hot, but not as hot. A poly tank needs to be reinforced (well) and since it is a fairly good insulator, the acid is slow to cool to a usable temp.
How much is the safety worth? OSHA will have an input on safety equipment required. EPA will have an input on storage and the mixing area.

James Watts
- Navarre, Florida
October 30, 2009

---

Insightful answer, Jim. Having been splashed with concentrated H2SO4 myself when someone was careless with a drum pump, I wonder if it is really necessary for the average plating shop to work with 96 percent acid instead of 48?

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
November 2, 2009

---

Wear all the protective equipment mentioned above and make sure it fits! The most important thing is that you add acid to water - NEVER water to acid. As you add the acid to the water, do it slowly and stir it well.

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
November 29, 2009

---

Good tip, Trevor.

Jeffrey Holmes, CEF
Spartanburg, South Carolina
November 30, 2009