Corrosion Resistant Fasteners 2

[ansys54]

Not sure if such a steel exists but here goes. We have a trench drain in a concrete slab. Draining into the trench is 50% Sodium Hydroxide(Caustic) and 93% Sulphuric Acid. Rather than form a ledge into the concrete to carry the trench grating, we're considering installing angle iron with bolts into the existing trench wall.

Good idea or Bad?

 

[evelrod]

Bad.

Rod

 

[Metalguy]

ansys54,

Interesting. *IF* the pH ends up anywhere near neutral you may be OK-assuming they are mixed well before they reach the steel. The steel will survive the caustic OK, but not the acid. If you need a metal to resist the acid, holler back.

 

[ansys54]

Sodium Hydroxide PH is 14 and 93% Sulphuric is 0.3. I suspect a "Bad" and a "holler back" are consistent with what I thought but wasn't sure until now.
Thanks to both of you.

My specialty is concrete so if I can ever be of help just ask.

 

[tomwalz]

Sorry,

I didn't get it all?

Is the NaOH and H2SO4 going down a tRench made of concrete or it is lined?

tom

 

[ansys54]

Trench is made of concrete.

 

[Metalguy]

Are they mixed *before* they enter the trench? That acid by itself will destroy concrete.

 

[ansys54]

Yes they mix then spill onto a coated floor and run into the trench.

 

[Metalguy]

Good! Do you know the approx. pH of the mixture?

 

[kenvlach]

I'm curious,
Does your concrete have a coating or sealant for protection?
[If not, I suggest a clear, penetrating epoxy sealer or a coating of Derakane vinylester epoxy]

Do you have an EPA or other government permit for this hazardous waste treatment process?

 

[ansys54]

I don't Metalguy however that's a good and obvious question which I hadn't thought of until now. I will test it.

Kenvlach, this is not effluent and is NOT discharged directly into the environment. It gets recycled back into the process after it enters the trench.

 

[plasticfreq]

why can't / don't you use an angle made from vinyl ester frp? currently making many parts similar to this application for an electro galvanize line...works beautifully...
plasticfreq