Neutralizing Sulfuric Acid in an FRP Tanker/Resin Liner

This scares the $4!t out of me.

You're working with three different nasty acids and bleach in an unknown plastic tank without knowing how to safely neutralize any of them. Did it dawn on you that the reason your sulphuric acid embedded into the plastic is that you have the wrong plastic. I think that you're eligible for a chemical Darwin award.

Could you possibly get an ammonia/wetting agent/water solution into it and slosh it around? Hopefully this basic solution would penetrate enough to react with the h2So4 and neutralize your problem.

That's a little harsh, I'd say.

Soap or washing soda will neutralise it too.

Trick is knowing when it is done neutralising.

This absorbent liner sounds a bit dodgy. How far into the GRP has this soaked? You may not be able to totally neutralise all the absorbed acid.

How much is enough do you think?

I've only ever cleaned up spills.

What will you reline the tank with after the mechanical prep?

Tom, NEVER mix chorine bleach and ammonia.

Mag;I'm sorry if you misread my solution.What was meant was a very dilute Ammonia solution with a wetting agent such as Shacklee Basic H orI.Mixed with water at a very dilute state I have seen extremely good results.I must add that I am not a Shacklee dealer but only a frequent user.Nowhere was Chlorine in any form mentioned!

Tom, this was in the original post: "chemicals like bleach, h2so4 and hcl or hfl". Both bleach and hcl contain chlorine, and hfl (which has fluorine) is not so good either - also can be written as NaOCl, HCl, HF.

NaCl (table salt) also contains chlorine. What's your point?

In my book "hauling chemicals like bleach" is chlorine-based unless otherwise specified.

when you speak of a liner, what do you mean? Is this a tank made entirely of reinforced fibreglass? Such a tank will become hydrolyzed ofer time and the surface will dissolve and the material become porous and on it's way to failure.

Normally, a tank will be lined with a plastic that will tolerate the contents. HDPE is commonly used for this. HDPE does not absorb and can be washed easily.

A tank liner should be an impermeable material that absorbs nothing. The fact that is has absorbed sulphuric acid means it has failed, and the tank must be relined. Something in your comment leads me to believe that you speak of an insulating liner, like foam or glass fiber??

In FRP (GRP) terminology, the "liner" is more often a resin rich layer 0.1" or thicker than it is a layer of thermoplastic. That liner consists of a layer or two of veil which can be synthetic or "C" glass which is laid/wound on the mandrill in ribbons and saturated with resin. This is backed up with two or more layers of "E" glass chopped strand mat before the structural laminate begins (the structural laminate typically being beefed up with a woven or stitched continuous strand roving). Thermoplastic/fluoropolymer lined FRP vessels (aka dual laminate) have their niche in the industry, but aren't nearly as common and are considerably more expensive to produce.

In some marginal applications for the resin material (bleach and sulfuric being two common ones), the liner is chemically attacked and eventually has to be replaced to protect the structural laminate. Unfortunately, as described herein, that's a tricky thing to do. I'm not sure I have a better suggestion than have already been described above for neutralizing, unfortunately. Respiratory protection and ventilation for the workers are obviously key.

What might help in the future is a couple of comments on bleach and sulfuric storage - a little off topic, but might help the liner last longer in the future - bleach storage in FRP can be very destructive without proper pH control - check with the resin supplier for more information on that. Also, if you're ever diluting sulfuric acid, try not to do it in an FRP tank - diluting sulfuric is a very exothermic process, and the heat can trash your tank quickly.

Have you tried sodium bicarbonate on a sample patch?

Yes, sodium bicarbonate will neutralize the acids without the high pH of sodium carbonate, which may damage the tank further; there is good advice in several of the above posts.

Unless you intend to remove the contaminated material, neutralisation would seem futile at best and potentially outright damgerous.

Any neutralisation will leave "salts" behind creating a porous liner that now has water soluable elements soaked within the matrix.

Anything that you now add that contacts the liner will be contaminated by the materials absorbed in the liner and the liner will absorb portions of the contents. (Like a sponge)

I suggest that you get your staff appropriate PPE (Personal Protective Equipment) and then remove the defective liner. Sounds like they need full respirator gear that is also suitably selected to withstand the product that has been used inside the tank.

A well-intentioned warning by mag to "never mix chlorine bleach and ammonia" was treated badly and rather dismissively by some on this thread. So I will spell it out, even though you are presumably not children. The OP stated that the tank under discussion had been used for hauling chemicals like bleach, h2so4 and hcl or hfl around. Since they "through(sic) sulfuric in there, and now when our guys grind on it,they are exposed to heavy amounts of sulfuric", we can assume that the tank is not being cleaned or drained, and therefore residues of chemicals like bleach, h2so4 and hcl or hfl are present in the tank. Therefore if you add ammonia, even if it is a dilute solution, to the tank, you will be chancing a mixture of chlorine bleach and ammonia. Perhaps you feel comfortable with creating a mixture of unknown components (if you know all the components of the mixture, please send a post listing them) when there are at least two different types of reactions possible, that is, acid/base neutralization and oxidation/reduction, but well meaning people use a short form of statements like "never mix chlorine bleach and ammonia" as a way to avoid unnecessary deaths.

A bit of history: Years ago a janitor at our location was cleaning toilets, and added chlorox and an ammoinia-based cleaner (forgot the brand) and passed out from the fumes. Had to remove him to the hospital myself. Not an experience anyone should repeat.