The authoritative public forum
  for Metal Finishing since 1989
  

  -----

Piping and valving materials for full range of sulfuric acid concentrations

2004

We are designing a mineral processing plant in Western Australia for the extraction of nickel and cobalt hydroxides. As part of the plant we will build a sulfuric acid plant (4400 tons/day). We will have sumps and sump pumps in a few locations on the mineral processing plant. sulfuric acid concentration in the sump can be in any concentration, say in the range of 0-98.5%. Temperature is ambient, 15 to 40 deg C.

Question: What materials of construction do you recommend for the discharge piping from the sumps and for the valves on the lines.

Thanks,

Zvi Yom-Tov
Process/mechanical engineer - Perth, Western Australia

---

2004

Hi Zvi,

Firstly, please go to the archives and have a gander at the following # 8698 # 15290 # 18942 and perhaps # 12244 as well as # 22519

This will/should cover all points.

You didn't mention temperature or pressure. However, ordinary type l uPVC can have its working pressure increased and also have an improved temperature deflection if one uses a dual laminate construction. There are, of course, other thermoplastics (CPVC, PVDF, HALAR etc) but the cost zooms. I am somewhat biased against fibreglass itself where one encounters varying concentrations of sulfuric as it will fail when exposed to higher concentrations .... even in the battery filling field using 36% sulfuric, FRP ducting has failed at many Companies ... the solution being to use PVC only. I understand that the Companies were Prestolite, Ford, Varta .... and GM switched to only PVC.

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).

I am providing technical service to the maintenance and operation of a nitric acid production plant. A 3" waste water acidic line downstream of pump discharge has occurred pinhole problems, and by changing the piping material from 316L to 316Ti could not solve the problem. The line conditions are 40 degC, 4 barG, H2SO4 conc 1% max. The 8" header is constructed from FRP/PE lined pipe, thus I am thinking if this is a suitable solution for the 3" line. Question; please guide me the limitation of several materials against limitation to H2SO4 conc %, temp, pressure, and probably velocity.

Duane Evans
- Shanghai, China
2007