Remove rust spots from concrete help!

[aja8888]

Recently, I had the flower bushes fertilized and some of the fertilizer pellets ended up on the concrete driveway and entry walk. Since it rained, some rust stains have appeared where the pellets were not swept away after the fertilizer was applied. I tried the vinegar/water mixture trick to no avail. Before I spend money on chemicals, which may not work well either, does anyone have a positive experience getting rid of these rust stains? I'm seeing mixed reviews on chemicals recommended out there on the 'net.

Thanks!

 

[latexman]

If you have hydrogen peroxide (3%) at home, try that before you buy something. It may take repeated treatments because it is not too strong. If it looks promising, but slow, you can buy 30-35% hydrogen peroxide just about anywhere, like Walmart.

 

[ncbill]

Be extremely careful as to what chemicals you put on concrete.

I've had to pay twice now out-of-pocket to repair the short concrete sidewalk out in front of my place.

After others in my family put "concrete-safe" ice melt chemicals on it.

Nowadays if there's a risk of snow (or more likely freezing rain) I spread an old painter's tarp over it beforehand.

 

[aja8888]

If you have hydrogen peroxide (3%) at home, try that before you buy something. It may take repeated treatments because it is not too strong. If it looks promising, but slow, you can buy 30-35% hydrogen peroxide just about anywhere, like Walmart.

I may try that. I know there is a product called Naval Jelly that contains phosphoric acid, but that maybe to severe?

 

[ShokWaveRider]

I use the Muriatic Acid I have for use in the Pool. But you need to be very careful and not leave it on too long. I would dilute it about 4:1 and try it out. Have a hose handy to wash it away. Check YouTube on how to remove rust from concrete with Muriatic acid.

 

[OldShooter]

Are you sure it's rust? It seems unlikely that fertilizer pellets would contain a significant amount of iron. The ingredients list should tell you. Or maybe the manufacturer support line would have suggestions for you.

That said, Naval Jelly is pretty mild stuff. You could give it a try, but don't leave it to soak. Phosphoric acid is used in munch higher concentrations to etch concrete prior to painting.

 

[erkevin]

Power washer?

 

[Mark1]

I haven't tried it on concrete stains, but I do have some oxalic acid for removing rust (bought it on Amazon years ago). It is a strong chelating agent for metal ions, so it might attack the calcium in the concrete, as well, and change the appearance so blending the area of treatment may be necessary.

 

[aja8888]

I haven't tried it on concrete stains, but I do have some oxalic acid for removing rust (bought it on Amazon years ago). It is a strong chelating agent for metal ions, so it might attack the calcium in the concrete, as well, and change the appearance so blending the area of treatment may be necessary.

Oxalic acid is in Barkeepers Friend household cleaner. I may give that a try.

 

[jim584672]

I have found whitening toothpaste to be good at stain removals.

 

[38Chevy454]

Oxalic acid is also sold as wood bleach in hardware stores. You can buy it powdered form on Amazon for relatively cheap.

 

[aja8888]

Are you sure it's rust? It seems unlikely that fertilizer pellets would contain a significant amount of iron. The ingredients list should tell you. Or maybe the manufacturer support line would have suggestions for you.

That said, Naval Jelly is pretty mild stuff. You could give it a try, but don't leave it to soak. Phosphoric acid is used in munch higher concentrations to etch concrete prior to painting.

Yes, it contains water soluble iron, manganese and magnesium. Definitely formed rust.

 

[arbeadub]

Maybe try calcium rust stain remover from a dollar store, its used for toilet ring stains, as said earlier dont leave it on too long.

 

[braumeister]

It doesn't sound like rust to me (fertilizer pellets?) but if it actually is rust, the traditional cleaning methods are

• lemon juice and salt
• oxalic acid
• ammonium bifluoride

 

[aja8888]

It doesn't sound like rust to me (fertilizer pellets?) but if it actually is rust, the traditional cleaning methods are

• lemon juice and salt
• oxalic acid
• ammonium bifluoride

I'm pretty sure it's iron oxide stain due to the water soluble iron in the pellets.

 

[aja8888]

Doing an exhaustive net search, I think I will try a small sample of this product based on many good reviews:

Singerman Laboratories Rust Remover for Concrete

Rust Cleaner for Concrete, Stone and Masonry Makes the concrete or stone surface look like new. Frankly, we've been unable to find another rust remover that actually removes rust stains from concrete, except those that are so harsh that they remove the stain by also removing the concrete.

sealgreen.com

The MSDS says it contains - Proprietary mixture. Contains sodium hydrosulfite.

Videos show it works pretty well.

 

[MC Rider]

Simple Green and a rag has worked for me on greasy oily car stuff on concrete.

 

[aja8888]

Simple Green and a rag has worked for me on greasy oily car stuff on concrete.

I don't have greasy oily stuff (yet).

 

[MC Rider]

Might work for rust too?

 

[calmloki]

Iron on a lawn makes it really green. Having substantially changed our smooth finish garage floor in some spots by trying to remove an oil stain I'd stay away from Acid Think I may have used muriatic but could also have tried sulfuric. Have used hydrogen peroxide on a number of blood stains - reacts with the iron and foams like mad, doesn't harm jeans.

 

[aja8888]

Might work for rust too?

Maybe I'll give that a try as I have 1/2 jug in the garage. I know it cleans aluminum parts (valve covers) pretty well.

 

[MC Rider]

I don't think it can hurt.

 

[Sconie]

Oxalic acid, also sold commercially as Iron Out is what you want.

Removing iron stains from concrete

 

[Time2]

I have used Whink Rust Stain remover on many items, it works very, very well, but, I have not tried it on concrete but I would if I had a problem. I would give it a try in an inconspicuous area first. Have a hose handy to wash it away. Be aware it does have a chemical that you don't want to inhale or get on your skin. Hydrogen Fluoride, this it is pretty mean stuff. Whink has between 1.5% and 3.5% hydrogen Fluoride. Here is a toxicity summary.

Hazardous Substances Data Bank (HSDB) : 546

Annotations submitted to PubChem by Hazardous Substances Data Bank (HSDB).

pubchem.ncbi.nlm.nih.gov

 

[aja8888]

I have used Whink Rust Stain remover on many items, it works very, very well, but, I have not tried it on concrete but I would if I had a problem. I would give it a try in an inconspicuous area first. Have a hose handy to wash it away. Be aware it does have a chemical that you don't want to inhale or get on your skin. Hydrogen Fluoride, this it is pretty mean stuff. Whink has between 1.5% and 3.5% hydrogen Fluoride. Here is a toxicity summary.

Hazardous Substances Data Bank (HSDB) : 546

Annotations submitted to PubChem by Hazardous Substances Data Bank (HSDB).

pubchem.ncbi.nlm.nih.gov

View attachment 51205

I've dealt with this stuff before. It contains hydrofluoric acid and pretty dangerous. But will work well. I totaly forgot about this stuff. Thanks.

If you read the case reports in the tox report, I am surprised this stuff is still available to the public.