Spilled acids on concrete

[50AE]

I accidently spilled a solution of diluted H2SO4, HNO3 and HCl acids on the concrete at my working place. I was busy, so I decided to let them dry. Now I'm let with big white spots on the concrete.

My questions are:

-Are there still acids remaining in the concrete, even if it's dry?

-What are the white spots?

-How can I clean them?

[Ralph]

your white spots are probably clean concrete concrete is comprised of carbonates and silicates and carbonates are particularly susceptible to all of these acids and will form the (usually in the case of the cations found in concrete(sometimes not sulfates) soluble compounds. They will have been completely consumed so there should be no residual acid (add some water if you notice effervescence than there must be some residual acid though they are likely to have evaporated off if not consumed).How on earth did you manage to spill all 3 acids at once in your work area ? (I cant think of a single use that uses all 3 acids)

[bikemaster]

I think that the first thing that you should do is to neutralise your concrete with a solution of sodium bicarbonate. If you already do this, wash the concrete with water to remouve all the solube salt that you produce. Sadly, I am pready sure that the white spot will stay there because the HCl (if really concentrate) will like "over wash" the floor.

[50AE]

I am lucky, the white spots went away with some pressure and a wet sponge. I think this thread was the most useless one I've ever created.

[Swede]

Don't feel bad. I once washed my hand by pouring concentrated HCl over it by upending the jug and allowing it to flow freely. I thought the jug was water!

 

After a panic period (When in trouble, when in doubt - run in circles, scream and shout) I washed my hand, checked the concrete. It was VERY clean, but the carbonates in the concrete kill the acid pretty quickly.

 

Oddly enough, my hand didn't even turn red. Don't try that with sulfuric, nitric, and especially not hydrofluoric. In the latter case, you die.