In Reply to: Re: the relationship with HDPE Tank & Sulfuric Acid posted by Goh on 06/07/03 at 2:48 AM:
Black colored resin will hide the discoloration but you will not be able to easily judge just when there is so much discoloration that the product is going to become tinted. Black natural and white will all suffer essentially the same degradation and the same degradation rate. This is a strong function of the actual percentage H2SO4. Dilluting to even 90% will help a lot in tank life. You have to decide if your process can stand that. By the way, car battery cases are made of a slightly toughenned grade of Polypropylene. And they run for years in under 50% acid. PP is not as resistant as HDPE because of its tertiary hydrogen which is a bit more subject to chamical attack.
Without looking up corrosion rates in handbooks, it is a fair speculation that fluorocarbon polymers are all much more resistant to acid attack. Consider teflon, Kynar PFA and the like only if your tank is not too big - Large scale gets costly with these materials. Lining is also costly. Many large scale operations just replace the HDPE tank every year or two after looking at cost per year of operation.
Let me know if you need a consultant or connections to tank mfgs or lining people. You can cheaply line a metal or concrete pit with HDPE. For considerably more (10X) you can have a fluorcarbon liner. I operate out of Houston.