Material Selection for Sulfuric acid 2

[Valving]

Hi there,
a pump vendor proposing cast iron pump for sulfuric acid. (%98 at 40 deg. C ( 104 F)
gjl-200 = grey cast iron

I could not find any solid literature defending this. Only high-silicon cast irons looks
suitable.
Could I have your input?

 

[EmmanuelTop]

There has been plenty of discussion on this subject. Use "search" feature or check

http://www.eng-tips.com/search.cfm?q=Material+Selection+for+Sulfuric+acid&action=search

Dejan IVANOVIC
Process Engineer, MSChE

 

[EdStainless]

Thank you EmmanuelTop.
The search does work.

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P.E. Metallurgy, Plymouth Tube

 

[Valving]

I know how to use search thanks. I was in some of these discussions.
However each application has different characteristics.
I searched a lot for cold %98 acid but could not find
solid proof - different sources contradict with each other.
Thats why open the thread.

 

[EdStainless]

Do you have the MTI MS book on sulfuric?
It is about the most definitive source.
Gray CI is not a very good option. It is susceptible to cracking (oxidation of C flakes).
A ductile iron is a bit better. But they both suffer from velocity related effects.
In a pump you are better off with a high Si CI (14.5% F47003).

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P.E. Metallurgy, Plymouth Tube

 

[georgeverghese]

Often, what materials are selected is not based on the normal operating conditions or chemical components in the service fluid; its the off normal service conditions and contaminants that cause accelerated corrosion; such as lower acid concentration ( higher water content ); what off normal contaminants do you expect ?

 

[Valving]

Thanks for input.
@EdStainless : I dont have this book and I guess it is not sold anymore. I could not also find it on web.
@georgeverghese : IT will be a new line so we have only these data.
Overall, I believe standart iron would be risky considering in such plants it is not easy
to control process and characterisics may change.

 

[EdStainless]

You can buy it from NACE

http://nace.org/cstm/Store/Product.aspx?id=21943026-032b-4de7-9835-47723c96b07b

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P.E. Metallurgy, Plymouth Tube