Where the
world gathers for metal finishing
Q&As since 1989


-----

Material of pickling tanks

 

Dear Sir,

We are looking for pickling tanks for hydrofluoric acid+nitric acid in one tank, temperature 60 °C. There will be dosed hydrogen peroxide to this tank. What's the best material for these tanks?

Thank you for answer,

Jerry Mokhhra
- Jaipur, India

---

 

Hi Jerry,

Um. PVC is out. So is titanium. Ditto for PP and Pe and fibreglass. Am not sure about stainless but have doubts.

You didn't give the tank size. It's always helpful to know this.

You could consider the dual laminate fluorocarbons but I have a feeling that PVDF is OK and should cost far less, too, than Halar or Tefzel.

Due to the temperature it is highly necessary to 'armour' those thermoplastics with fibreglass ... and only use a fabricator who is knowledgeable about making dual laminate tanks.

I hope that this is of some help.

Freeman Newton [deceased]
(It is our sad duty to advise that Freeman passed away
April 21, 2012. R.I.P. old friend).

Hi Jerry M,

Try fabricating a mild steel tank and coating the entire tank with FRP. This will surely solve your problems.

Regards,

VIJAYAN NAIR
- MUMBAI, MAHARASHTRA, INDIA
 

---

Jerry,

I am biased against fibreglass BUT have used it very frequently but mainly for dual laminates where it serves as a structural reinforcer of the weaker thermoplastics.

IF you used a very good resin. IF you got a very good bond to the steel tank. IF you had sufficient build-up, ie. thickness. IF you had a resin rich surface (the so-called corrosion barrier) using synthetic mat and veil. IF the surface was never scratched. Then MAYBE it might last. Maybe! But if,if,if any glass fibres became exposed, oh dear, the HF would eat them with impunity.

That is WHY I didn't recommend FRP before.

Freeman Newton [deceased]
(It is our sad duty to advise that Freeman passed away
April 21, 2012. R.I.P. old friend).
 

You can use p.p fabricated tanks also. As it can run much better in 60 degree temperature.

Puneet Chopra
- Ahmedabad
2006