Sulaiman
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? How to recover waste mercury compounds ?
Sometime later this year I intend to do a little chemistry with mercury and its compounds,
if I can confidently recover the mercury after experimenting,
as I want negligible mercury environmental pollution.
I intend to have a mercury waste container and a still for final stages of purification,
but I do not have the experience to know what are the general requirements for mercury recovery,
if there are any.
Anyone here have experience of mercury recovery from amalgams and compounds that can advise me in advance ?
CAUTION : Hobby Chemist, not Professional or even Amateur
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j_sum1
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This offering from NileRed is probably useful.
https://www.youtube.com/watch?v=S4T57SFntIs
Cody's lab has lots on Hg including recovery of metallic. (Ignore the loo flush. It ain't worth it.) He also has an early one where he cleans up a
mercury spill. I don't think he is that cautious any more. But that video demonstrates good practice.
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Sulaiman
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I have already watched almost all of Nile Red's videos 
I will see how the final stages of mercury recovery turn out.
I like the 'general' approach of converting all mercury to a single compound (HgS in this case) then processing that.
What I am considering is very difficult ... near 100% yield
as anything else = toxic waste.
I am hoping for something simple and universal like
' all mercury compounds and/or amalgams yield elementary mercury when ...... '
or some such simple approach.
As mercury and its salts are now 'illegal' here in UK
I assume that there are probably no convenient mercury recycling/waste facilities available to me,
so 99.9...% recovery is the only option that will allow me to experiment.
CAUTION : Hobby Chemist, not Professional or even Amateur
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Amos
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Mercury that is in solution can be converted back to metallic mercury with more reactive metals; placing these solutions over a considerable piece of
copper wire should be pretty selective for mercury as copper is only capable of displacing a few metal ions in single replacement reactions.
Aluminium, iron in the form of steel wool, or zinc can all work too. If the mercury thus precipitated is dirty (which is likely if a high-surface area
metal source like aluminium foil or steel wool was used), it can likely be cleaned pretty effectively by prolonged stirring with hydrochloric acid or
sodium hydroxide solution, as these are reactive toward many metals but not toward mercury itself.
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MrHomeScientist
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I believe mercury amalgamates with copper though, or at least sticks to it. My dad used to coat copper pennies with Hg back in his school days. I
would use iron instead since that's what Hg flasks are made of, so compatibility won't be an issue.
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Lefaucheux10
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Iron is one of the only metal wich dont amalgamated with mercury :/
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MeshPL
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There are bunch of others, by example platinum group metals don't alloy with mercury... there are more like this: tungsten is another example.
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Metacelsus
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I've heard sulfur is good for cleaning up mercury spills. It reacts with mercury to form the insoluble sulfide. However, it wouldn't be very useful if
you wanted to recover metallic mercury.
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Melgar
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If mercury is illegal in Britain, then I suppose you could always say that you found some in the course of working on some antique machine, and felt
it was your civic duty to turn it in to the proper authorities. If they suspect that you're doing it too often, I suppose you could insist that every
time you find even a drop, you immediately stop what you're doing to turn it in, insisting that you wouldn't want to store it, because that's illegal.
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