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Mercury on gold


#1

Hi Guys, I have a question. A customer of mine is a chemistry
teacher. He spilled mercury on his 14kt yellow gold wedding ring he
just bought from me less than 6 months ago. He brought it to me in
a zip loc bag. Are there any precautions I should take with this
stuff? How do you reccomend I remove it? I was going to rubber
wheel it off. The more I thought about it. Maybe that’s not the
best choice. I’m open for suggestions. Thanks in advance. :slight_smile:

God Bless you
~Poppy~
www.jewelrybypoppy.com


#2

Stop! Don’t even think about rubber wheeling! We need John to give
the definitive answer on this one but I’m sure that you don’t want to
be rubber wheeling the mercury! The fact that the chemistry teacher
brought it to you in a zip lock bag should be a big warning.

Marilyn Smith


#3

The exact same thing happened to me. Be REALLY careful. For several
reasons. If you try and heat it off (watch those vapors!) and don’t
have the right temperature, it will bond further with the gold. This
exact scenario happened with a friend of mine. She took it to a
jeweller who heated the ring and returned it in two pieces still
contaminated, but didn’t look “stained” anymore. The gold was
extremely brittle. She brought it to me and it had to go to to a
refiner who put it in (pretty sure here…) hydrochloric acid to
remove the mercury. I am sure there are those on the list with
greater knowlege and experience, but this was mine.

good luck,
stephanie morton


#4

Dear Poppy,

We have come across a similar situation and the method we adopted
was:
If it is a product without semi precious stones which will not loose
its quality while heating , heat the product with a mild flame in a
well ventilated place or under fume cupboard. Later u can polish it.
We didn’t have any complaint later.

Regards
G.Rajendran, Titan Industries ltd., jewellery Division, India


#5
    Hi Guys, I have a question.  A customer of mine is a chemistry
teacher.  He  spilled mercury on his 14kt yellow gold wedding ring
he just bought from  me less than 6 months ago.... 

G’day; My wife who also worked in chemistry got mercury on her
wedding ring. It was easy to remove in the lab situation by putting
the ring on a tripod and gauze, in a fan ventilated fume 'cupboard’
and heating it with a bunsen burner until the ring became completely
black with copper oxide and free from mercury (the ring was 9 carat
gold - all I could afford!) I then tipped it into 10% sulphuric acid,
and the black almost disappeared in a short while. I buffed it with
tripoli (which is fine pumice powder bonded with soap or wax) and
finished it by buffing with rouge, then a clean buff and the ring
was just like new; she still wears it. Several students over the
years came with the same problem and the same result was happily
obtained.

Possible problems:- Mercury vaporizes below the temperature of gold
solder, so you don’t need to heat it too strongly; NOT to red heat,
for instance. Mercury vapour is poisonous, and must not be inhaled,
so the vaporization must be done in the open; watch which way the
wind is blowing! Or do it close to an exhaust fan.

Someone may suggest the mercury is dissolved with strong nitric
acid, which won’t dissolve gold. No, it won’t, but you’ll have
mercuric nitrate solution which plates gold with mercury very nicely!

If an attempt is made to abrade the mercury from the gold, it won’t
be very successful; for mercury being a liquid at room temperature,
will rub over the the place just abraded and you will have to keep on
with it. Some will adhere to the abrasive and give the same result.
If the ring holds stones, then so long as they are diamonds, or of
the corundum family, such reasonable heat will not spoil them. But
don’t suddenly cool them in the pickle - there is danger of them
cracking. Heat and pickle sensitive stones must be removed before
treatment. The whole business takes only a few minutes. Don’t
charge and you’ll have a grateful customer to tell friends how good
you are! – Cheers for now, John Burgess; @John_Burgess2 of Mapua,
Nelson NZ


#6
  He  spilled mercury on his 14kt yellow gold wedding ring ....  
Are  there any precautions I should take with this stuff?  How do
you  reccomend I remove it? 

Poppy, you could immerse the ring in 50/50 water/Nitric acid to
remove the free (surface) mercury. This won’t remove the mercury that
has already formed an amalgam with the gold in the ring - that you
would have to file off, then sand and polish - all of which would
produce breathable Mercury-bearing dust. The Nitric acid will also
etch the surface of the ring - maybe to the point where it’s stuffed.

You might be told that you can remove the Mercury by subliming it -
heating above 400 deg C. So you can, but doing so would put your and
others around you at risk of inhaling Mercury vapour - not something
to be considered for the sake of a few grams of 14k gold.

Make your client a new ring and get rid of the old one to your
refiner - hitting him in the hip-pocket might teach the teacher to be
less careless when handling toxic materials.

cheers

Al Heywood


#7
Are  there any precautions I should take with this stuff?  How do
you  reccomend I remove it?   I was going to rubber wheel it off. 

The mercury can penetrate quite a bit, so rubber wheeling it off may
need you to take of substantial metal, plus it then creates toxic dust
in your bench. Instead, assuming the ring has no heat sensative
stones, etc, take it outside, or somewhere with VERY good positive
ventilation, put yourself “upwind” of the thing, and anneal it. At a
low red heat, such as typical for annealing golds, the mercury is
vaporized and driven off, with no loss in the gold, which then will
just need to be repolished. Obviously, the mercury vapor is NOT
something you wish to breath, so “outside” is better than in your
shop. If the spill is very new, and not much mercury so it didn’t
penetrate, you can also remove a good deal of it with dilute nitric
acid, but this won’t get much below the surface. Then, with at
least the amount of mercury reduced, anneal the thing as above.
Environmentally, of course, this isn’t so great to do a lot of, since
the mercury that’s vaporized condenses out and slowly settles to the
ground downwind of you. But the amounts involved with cleaning up
just one ring are so minescule that you probably don’t need to feel
enviro-guilt over it.

Peter Rowe


#8
    Stop! Don't even think about rubber wheeling! We need John to
give the definitive answer on this one but I'm sure that you don't
want to be rubber wheeling the mercury! The fact that the chemistry
teacher brought it to you in a zip lock bag should be a big
warning. 

Correct! Mercury is very poisonous! I should think that the prof
would’ve pointed that out, Also, the mercury has undoubtedly
amalgamated with the gold, and just polishing off the surface won’t
do the job. The only way I can think of to fix the ring (although
admittedly not an expert in this sort of thing) would be to
completely remove the section of the ring with the mercury on it and
replace it.

Margaret


#9

Hi Poppy, Mercury fumes are very dangerous. Don’t heat the ring in
an open flame if there is a chance of breathing the fumes. You might
try a trick the old prospectors used to separate mercury from gold.
Cut a raw potato in half. Press the ring between the potato halves
(center). Sort of like making a cuttlefish mould. I would wrap this
in foil and bake outdoors in a charcoal grill. The mercury will
vaporize into the potato, leaving the gold behind. I have not tried
this before, so no guarantees. PS, DO NOT EAT THE POTATO or dump it
where an animal might eat it. Hope this helps. Will Estavillo, now in
Bisbee.