Help - Acid stained concrete

[smidsy]

Anyone know what I can use to clean a battery acid stain off concrete - it's left a big white stain even after a decent hosing down.
More important than the stain is that one of my cuts is in to everything so I've had to lock him inside until I can clear this up.

Cheers

[DJ’s Timber]

The acid hasn't stained the concrete, it has cleaned it. Now that you have hosed it down you have neutralised the acid, so it is safe now.

[smidsy]

Ok next question.
The driveway is faded black in colour, how do we recolour the clean part - this is a rental place and where the acid has been is very noticeable.

[Bob38S]

The faded black is mould, hire/buy a water blaster - Karcher/Gerni type and spray blast the concrete clean. Within a couple of weeks you shouldn't really notice the difference.

Bob

[MrFixIt]

The acid hasn't stained the concrete, it has cleaned it. Now that you have hosed it down you have neutralised the acid, so it is safe now.

Water DOES NOT NEUTRALISE ACID! Water ONLY weakens the solution. The acid will remain active until it has lost ALL its acidity by a chemical reaction with the material with which it is reacting. There ARE chemicals that CAN neutralise the acid, though I don't know what to suggest.

Many years ago my BIL painted his trailer in our driveway. He used hydrochloric acid to wash away the overspray on the concrete agregate driveway. He DID hose it down extensively, however over the next few months the acid continued to eat into and leech away the cement in the concrete and much of the small blue metal agregate became loose. The "corrosive" action eventually stopped but it took quite some time, ie a few months.

There used to be a product available for this neutralising action, but it does not seem to be available now.

[solid art]

We do alot of acid stained concrete around here and I use it sometimes on my concrete countertops. It takes quite a lot water to wash away acid so neutralize it with ammonia, about a cup per 3 gal. (5L?). Add the ammonia to the water not the other way around. Pour it on, it works instantly, broom around, hose off. You can also use vineger.

Paul

[joe greiner]

You can also use vineger.

Paul

Might have your chemistry barse ackwards, Paul. IIRC, vinegar is also acid.

Joe

[David L]

Does not Baking Soda neutralise battery acid?
That's what I use to clean up my car battery.