Pipe material

[willf]

I need information regarding the construction material best suited through which I can feed Caustic Soda (15% concentration) and also Phosphoric Acid (30% conc).

 

[mohtogh]

for phosphoric acid: Hastelloy,polyethylene,rubber lined steel
for caustic soda:copper,bronze ,monel,(in all temperatures),poly ethylene
But you should mention temperature of solution.above mentioned materials are suitable for T<50 deg. F

 

[mcguire]

If you have no halide contamination, Sedriks recommends type 316 stainless for these environments in &quot; Corrosion of Stainless Steel&quot;.

 

[josephn16]

316 Stainless Steel would be fine for both services, but it will also be more expensive than some of the materials in mohtogh's post. Chances are your temperature is higher than 50 deg F, in which case Hastalloy and Rubber-Lined steel are still OK. Hastalloy is pretty expensive, even compared to 316SS. I have supplied many caustic tanks/feed systems in the past few years, and we use 316SS almost exclusively, and the few times we have not used SS, our clients have requested the use of Rubber-lined carbon steel.

 

[fertilisers]

i understand ss316L will serve the pupose,provided the material is free from halide.

 

[MJCronin]

willf,

&quot;mohtogh&quot; is incorrect in stating that copper and/or bronze is an acceptable material for any caustic soda solution. Copper bearing materials will be actively corroded. You should always be careful in eng-tips or any other discussion forums............statements and recommendations should be backed-up and other technical references cited

See this link:

http://www.oxychem.com/products/handbooks/caustic.pdf

304/316 stainless materials are acceptable for both services

MJC