[sdiy] products for rust removal - the joys of phosphoric acid

[aankrom]

Any poly-carboxylic organic acid will do - they form coordinate bonds 
with iron (and other metals). It's not that I am averse to using them, 
it's just that in this instance I need PA. "Sugar acids" are great for 
light rust on painted surfaces. Hey they may work as a final wash to get 
the Naval Jelly residue off!

AA

On Thu, 22 Dec 2011 16:56:53 -0800, David G Dixon wrote:
>> A better way to remove rust, is to soak the rusted object for
>> a couple of weeks in a mixture of molasses with four pars of
>> water. This is what the car restoration guys do.
>> I didn't believe it would work, but I tried it with a blob of
>> rust that I found on the roof - it turned out to be an old
>> double screwdriver.
>> Apparently the molasses has a compound that chelates the iron
>> in the rust.
>> The advantage is that the metal iron is not attacked at all.
>> Cheapest place for molasses is the stock feed store. Most
>> expensive is the organic health food place.
>
> Interesting.  Many organic acids (citric, malic, tartric, etc) 
> chelate iron.
> In fact, I have a patented process for nickel recovery from basic 
> ores
> containing natural nickel-iron alloys which uses citric acid in the 
> mix to
> chelate the iron as it dissolves and prevents it from 
> re-precipitating back
> out onto the leaching surfaces and stopping the leaching reaction.  
> I'm not
> sure what the organic acids in molasses might be, but this certainly 
> sounds
> feasible to me.
>
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