Re: Unknown Apparatus (mercury)

[Bernard Cleyet <anngeorg@PACBELL.NET>]

The best reference for decontamination I found: (note:  It requires
sulfuric acid.)


                                  6. Clean Up Procedures

 Wearing protective clothing, pools and droplets of metallic mercury can
be pushed                                together and then collected by
a suction pump. After the gross contamination has been removed,
sprinkler the entire area with zinc powder. Spray the zinc with the
dilute sulfuric acid.                                      Using the
sponge, work the zinc powder/sulfuric acid into a paste consistency
while                                              scrubbing the
contaminated surface and cracks or crevices.
To minimize contamination of housekeeping items, stiff paper may be used
to assist in                                               cleaning up
the amalgam.

After the paste has dried, it can be swept up and placed into the
plastic container for
disposal. Rags, shoe covers, sponges, and anything used for the cleanup
should be placed in                                               the
trash bag to be disposed of as contaminated material.
<http://www.pp.okstate.edu/ehs/HAZMAT/LABMAN/Chap1a3.htm>

the better ones:

Sprinkle sulfur powder, calcium polyphosphide with excess sulfur, zinc
dust or proprietry products like Mercurisorb, HgX on contaminated area,
using at least twice as much powder as volume of spill. Mix well if
possible. Allow time for mercuric sulfide, etc. to form, which can take
from half an hour to 24 hours. Sweep or vacuum up the powder, avoiding
generating dust. Use only special vacuum cleaners fitted with charcoal
filters.
http://www.usyd.edu.au/su/ohs/mercurys.html


Corrective measures included removal of the carpets, decontamination of
the house (i.e., several cleanings of floors, walls, and solid surfaces
with a product containing a metallic-mercury-sulphide-converting
  powder, a chelating compound, and a dispersing agent), and application
of a polyurethane coating to all floor surfaces. Subsequent analysis
indicated that the mercury concentration was less than 1 ug/m3
throughout the house.
< http://www.cdc.gov/mmwr/preview/mmwrhtml/00001499.htm>



the additional misc references I found in an unreasonable time:


Currently, mercury sulphide is the only mercury compound which is
accepted for
recycling. <http://www.google.com/search?hl=en&q=%22mercury+sulphide%22>



 It is our understanding that before preparing their Circular the DOE
did in fact carry out extensive investigations of landfill sites and
their surrounds and did not find the chemical contents of lamps was
causing any harm for concern. In fact, in this Circular they have
explained that the mercury is converted to mercury sulphide by some of
the other solutions in the landfill and in this condition mercury is
considered inert and insoluble so it does not contaminate the site. <http://www.balcan.co.uk/lampq_a.htm>



bc

P.s. contrary to the reference immediately above, HgS is highly toxic,
but does have a lower vapour pressure, and is easier to collect (HEPA
vacuum cleaner).  More:
<http://www.dentalmedical.it/inglese/entrap-system.htm>

 Still more:  Small amounts of mercury spillage can be cleaned up by
addition of sulphur powder. The resulting mixture should be disposed of carefully.
< http://www.altcorp.com/hgproperties.htm>




Pete Lohstreter wrote:
> PHYS-L@lists.nau.edu writes:
> > Zinc powder is good for mopping up the smallest
> > > droplets.
> >
> > I'd read sulfur for that use.
> >
> > bc
>
> Sulfur will coat the Hg droplets and reduce the vapor pressure a bit.  But
> the Hg is still in the elemental form and if the sulfur dust coating
> breaks then you are pretty much back where you started.
>
> Zinc on the other hand, will amalgamate with the Hg and drop the vapor
> pressure to virtually zero.  Only  heating to a fairly high temperature
> will release the Hg. ( not too likely during clean up)
>
> So - my vote is still with the Zinc Powder.
>
> PL
>
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