Sciencemadness Discussion Board

Acid Resistant Coating for Storage Purposes?

Farnsworth - 16-7-2012 at 19:04

I'm looking for something interesting.

Suppose one needed to store small amounts of mixed nitric and sulphuric acid in a non-acid resistant container. I know this is an unusual situation, but it is leading me into a particular experiment. For practical reasons I cannot use glass (unusual container geometry and I'm not a professional glass blower, basically.)

Are there any commercially available or synthable materials that could coat the inside of a metal or plastic container to make it resistant to the acid for an extended period?

elementcollector1 - 16-7-2012 at 21:32

Er... plastic? As far as I know, plastic is immune to acids. If I'm wrong, you could try Teflon.

blogfast25 - 17-7-2012 at 04:19

Yes, HDPE should do it. Starting from powder, 'rotamoulding' can be used to coat the inside of vessels, even oddly shaped ones.

[Edited on 17-7-2012 by blogfast25]

polymerizer87 - 17-7-2012 at 07:04

I have a synth for a acid resistant polymer they use as a coating for various products such as the interior of metal canisters. Although im not sure what your availability is for solvents such as n methyl pyrrolidone and o-xylene. The polymer is extremely easy to apply and just needs to be thrown in a 300 C oven to cure.

Endimion17 - 17-7-2012 at 07:26

Quote: Originally posted by elementcollector1  
Er... plastic? As far as I know, plastic is immune to acids. If I'm wrong, you could try Teflon.


Teflon is a plastic. ;)

HDPE, s mentioned, is ok. Not all plastic masses are inert to all common acids, but HDPE would be ok for mixture of nitric and sulphuric acid, if they aren't hot.

blogfast25 - 17-7-2012 at 07:52

Teflon is expensive and difficult to adhere to anything. It's a bit overkill for this application, IMHO...

AJKOER - 17-7-2012 at 08:19

Here is an alternative possible solution (?) that can be molded into shapes, scaled up, relativity inexpensive and generally availablel. Make vessels out of Plaster of Paris (CaSO4) and line with a suitable thin plastic sheet.

Obviously resistant to H2SO4, and the reaction:

CaSO4 + 2 HNO3 --> Ca(NO3)2 + H2SO4

may proceed slowly depending on temperature and the starting presence of H2SO4.

Downside: a short term solution as penetration of the plastic lining will introduce a Calcium contamination as Nitric acid attacks the CaSO4, and the vessel itself would be fragile.

Those with some working knowledge of pottery may also have some creative ideas as to composition and shapes.

[Edited on 17-7-2012 by AJKOER]

Twospoons - 17-7-2012 at 14:19

Isn't paraffin wax used to line glass bottles for storing HF? Maybe you could adapt that approach.