Removal of copper sulfate stains from concrete?

[Pablo]

Anyone ever removed blue-green copper sulfate deep staining from cured concrete driveway?

Tried vinegar. Nothing

Next ammonia- it works but slow. 2.5 gallons and lighter. It sorta lifts the blue and best to not rinse right away.

Not sure if strong citric acid would work

I bet HCl would work??

 

[Doc8404]

Why not Muriatic?

 

[Pablo]

Why not Muriatic?

That’s what I am asking. HCl = hydrochloric acid = muriatic

 

[benjamming]

HCl would also damage the concrete though.

 

[Pablo]

HCl would also damage the concrete though.

That is the rub

 

[vavavroom]

What do you suppose they make copper stain remover for?

 

[Pablo]

What do you suppose they make copper stain remover for?

For removing stains from copper?

If you know a specific product, out with it man!

 

[97prizm]

Anyone ever removed blue-green copper sulfate deep staining from cured concrete driveway?

Tried vinegar. Nothing

Next ammonia- it works but slow. 2.5 gallons and lighter. It sorta lifts the blue and best to not rinse right away.

Not sure if strong citric acid would work

I bet HCl would work??

Purple power which burns your hands like no other. Then power wash. CLR and a metal scrub brush. Simple Green has a concentrate that is for concrete and brick. It's designed for power washer use. Amazon has "pull it out" which looks like pour-n-restore which does work amazingly well.

 

[Pablo]

Purple power which burns your hands like no other. Then power wash. CLR and a metal scrub brush. Simple Green has a concentrate that is for concrete and brick. It's designed for power washer use. Amazon has "pull it out" which looks like pour-n-restore which does work amazingly well.

I have not tried those.

Purple Power is KOH based I believe.

You have experience with those with copper stains?

 

[97prizm]

Not copper sulfate per se but have dealt with heavy rust stains. Pour n restore works amazingly well on oil stains in concrete new or old. Home Depot has a rust remover that worked very well not sure if it would remove copy sulfate.

 

[Pablo]

Not copper sulfate per se but have dealt with heavy rust stains. Pour n restore works amazingly well on oil stains in concrete new or old. Home Depot has a rust remover that worked very well not sure if it would remove copy sulfate.

Oil stains different matter and certainly don't want oxidizers.

Most effective means seem to be a one-two punch.

CuSO4 + NH3. => (NH3)2SO4 and liberated Cu?? Problem being weakarse and variable grocery store ammonia solution. Some smell like water, other bottles at least smell.

Liberate the Cu (I can sometimes see it come up) then bind it with a (weak) acid but keep in water solution

I sprinkled citric acid crystals all over one area. Brushed it in really well. Rain coming today.

 

[Doc8404]

That’s what I am asking. HCl = hydrochloric acid = muriatic

Duh. Thanks for the reminder LOL.

 

[SHOZ]

Probably going to have to remove the cement to get the stain out I would guess. Which is what a strong acid or base will do.

 

[vavavroom]

For removing stains from copper?

If you know a specific product, out with it man!

I suppose humor is not helpful. As a former poolboy I'd try sodium carbonate, water, and forceful friction.

 

[Pablo]

I suppose humor is not helpful. As a former poolboy I'd try sodium carbonate, water, and forceful friction.

Will stew on that. Thank you!

 

[SubieRubyRoo]

How to fix concrete stains:

 

[bunnspecial]

No particular experience with this but putting on my chemist hat:

EDTA will chelate copper at mildly acidic pHs(pH 5 or so). If I wanted to brew something up myself, I'd try EDTA+an acetate buffer...

Ammonia by itself should work but I don't know that household ammonia is concentrated enough...

A paste of oxalic acid(Barkeeper's Friend) might work also.

 

[Pablo]

No particular experience with this but putting on my chemist hat:

EDTA will chelate copper at mildly acidic pHs(pH 5 or so). If I wanted to brew something up myself, I'd try EDTA+an acetate buffer...

Ammonia by itself should work but I don't know that household ammonia is concentrated enough...

A paste of oxalic acid(Barkeeper's Friend) might work also.

I was thinking the same!

Household ammonia is so variable, I mean I didn't actually assay it, but at least it should SMELL like ammonia, but some bottles have no smell and do NOTHING. Rip-off! When the ammonia works, the copper sheen is apparent in the water running off.

One of the problems is the size of the two areas, not insignificant. A meter wide by 2.5 meters long.

That is a lot of chemical. PLUS the stain is deeply penetrated.
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That said, copper sulfate did the job. It is is a very effective antifouling agent. Those two spots are north facing and hairy. The pressure washer kinda cleaned them, bleach kinda killed the stuff, but in short while black hairy nasty stuff, right back. Copper sulfate killed the algae and moss and kept it away all winter. But ahem..........yes.............stained. I knew it would, I just didn't know it would be permanent.

 

[SHOZ]

Borax and antifreeze will keep algae away. H2O2 will remove it. Maybe try some 30 % on the copper?

 

[Pablo]

Borax and antifreeze will keep algae away. H2O2 will remove it. Maybe try some 30 % on the copper?

H2O2 good idea.

Not wanting to pour antifreeze on the concrete. Thanks.