[kbarb]

I have about 4 - 6 oz. of Mercury left over from when I made a manometer over ten years ago.  It's been in a capped glass bottle every since.

But now it has some kind of light brownish coloration/scuzz where the mercury touches the inside of the glass vial - I'm assuming it's some sort of oxidation.

Is there some way I could reverse the oxidation, if that's what it is ? A small amount of mild acid ?
I have a high quality respirator for the molecule size of organic vapors if that's a concern.

Thanks,
Kent

[renge ishyo]

Assuming that what you have there is in fact mercury (II) oxide (check the wiki to make sure the data matches: http://en.wikipedia.org/wiki/Mercury(II)_oxide) then you can isolate elemental mercury by simply applying heat. Have a look at this site for a simple method to accomplish this:

http://www2.uni-siegen.de/~pci/versuche/english/v21-3.html

Since, the heat applied needs to be high I would make sure you have pure mercury oxide and not a mixture of components before you do this. One way you can check is by pounding a portion of your purported mercury oxide sample into a fine powder, measure the volume of the powder in an appropriate container and then measure the mass of the powder using accurate equipment. Calculate the density by dividing the mass by the volume; if it is mercury (II) oxide it should be about 11.14 g/cm³.

[Borek]

Note that heating it you will probably lose some of the mercury because of its volatility - so perhaps it is better to just get rid of the brown substance if it is in a minute quantities?

[408]

Filter through a filter paper with a pinprick in the bottom.  The oxide sticks to the filter and shiny Hg goes through.  I have not done this, so I am unsure how big the pinprick needs to be.

[kbarb]

I put up a photo of the little 4" high jar.
The web photo on my laptop looks a bit darker than the image as I photoshopped it - prob. just depends on what screen you're using to view it.
Anyway, you can see some residue sticking to the glass above the mercury,, but normally there are swirls of it all around the mercury.
But originally it was just a bottle of bright and shiny mercury.

And many thanks for the responses. I think I probably won't get into heating up the stuff as it sounds a bit dangerous, and I don't have that kind of safety equipment.
The pin hole in the filter sounds intriguing though.


 

[csrscience.com]

shake it around with HCl, and then reduce the mercury again with some metal such as iron or something that doesn't form an alloy.

the HCl should react with the Hg to get HgCl2, and then that would react to form iron chloride, and Hg.. which will sink to the bottom of the solution, then add it back to the mercury. and add a layer of oil up to the top of the lid so this doesn't happen again...

or you could send me the mercury

[kbarb]

Sounds interesting . . . but I didn't quite follow the sequence there.

I add a bit of HCl, then . . . what . . stick a bar of iron in there with the HgCl2 ?   iron filings ?
Then decant off the cleaned up mercury ?
I didn't understand the "add it back to the mercury." It sounds like I'm adding it to itself. I must be missing something.

[csrscience.com]

The HgCl2 will be in solution with out any mercury in the bottom.

Adding iron (check to see if it is more reactive, first - pretty sure it is though) will reduce the mercury chloride to mercury, and iron chloride. the iron chloride will be in solution, and the mercury will fall to the bottom of the flask.
Then take the mecury in that bottom of the flask, and add it to the clean mercury.

[sdnnet3]

i was working with a similar problem and i believe that adding aluminum to the hgcl2 forms an amalgam(alloy) than when seperated from the solution and added to DI water to react the Al leaves you Hg elemental. all waste from this process should be disposed of at a hazmat facility/waste collections.