[ExI] Ants to spike
brentn at freeshell.org
Tue Oct 20 16:46:32 UTC 2009
On 20 Oct, 2009, at 10:13, spike wrote:
> Anders, precipitating lead from paint chips can probably be done with
> ordinary household chemicals, but not with vinegar. Mineral spirits
> turpentine would likely be your best bet for getting the stuff into
> to start with. When you say precipitate it with salt, if you meant
> chloride, you can consult the periodic table and recognize that you
> form little or no lead chloride. So I can see at least two things
> in this
> approach that might explain your result.
> I may look up and try to estimate the lead content of paint, which I
> is very low, then sketch a device to extract it from a solution using
> electroplating. As low as lead is in reactivity and with that +4
> state, don't get too optimistic. Might need to figure out a way to
> the paint, then evaporate the solvent, then try to separate the lead
> the rest of the goo that is left over.
> Otherwise my guess is try to form a nitrate or a sulfide rather than a
> chloride, then try to extract the lead nitrate or lead sulfide using a
> Of course if you try to get either sulfuric or nitric acid, you may
> the attention of the authorities.
Most likely, Anders failed to extract much lead using 5% acetic acid.
Lead chloride is well-known in chemistry as one of the three insoluble
chlorides (the other two being silver and mercury.) The way I would do
this is to extract in 10% nitric acid. Lead nitrate is soluble in
water, so the reaction would be
Pb(NO3)2 -> 2NaCl (or, use 1 MgCl2!) -> PbCl2 + 2NaNO3.
The lead chloride is the only one of these species that is not water
soluble, so it will drive the reaction to the right. Also, while lead
does have a +4
(and a -4!) oxidation state, you'll usually find it in a +2 state.
The lead pigment used in paint was usually lead carbonate, which is
clearly a lead(ii) species.
Not a chemist, but I play one at my day job,
Brent Neal, Ph.D.
<brentn at freeshell.org>
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