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Mercury metal price experiences?

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LAN_403

plazmatron

Mon Dec 07 2009, 05:09PM

Registered Member #1134 Joined: Tue Nov 20 2007, 04:39PM
Location: Bonnie Scotland
Posts: 351

Klugesmith wrote ...

.......the contents look sort of dirty. Maybe when the McLeod gauge arrives I'll have to get some experience with cleaning the metal -- dilute nitric acid wash? Filtering through chamois? No distilling at my house, at least not of anything undrinkable.

By pouring the mercury into a dish, the dirt (probably oxides, and dust), can be gently wiped off the surface with a damp paper towel ( I have done this myself, and it is easy).
There is no need to filter through Chamois, unless you suspect there is significant of contamination by amalgamation with other metals.

Les

Nik

Mon Dec 07 2009, 11:21PM

Registered Member #53 Joined: Thu Feb 09 2006, 04:31AM
Location: Ontario, Canada
Posts: 638

To prevent evaporation the sample I have has a heavy oil on top of it (in addition to the thick plastic cap on the thick glass bottle). I don't know how well this works but it seems like an easy way to keep your lungs (and brain) safe.

Henry H

Thu Dec 10 2009, 09:06AM

Registered Member #2298 Joined: Sat Aug 15 2009, 08:16PM
Location: ex UK, now Santa Cruz, CA
Posts: 35

I am local and would happily buy a couple lb from you.

klugesmith

Fri Dec 11 2009, 08:22AM

Registered Member #2099 Joined: Wed Apr 29 2009, 12:22AM
Location: Los Altos, California
Posts: 1716

It's serendipity time. The development which made my day is oil for mercury.

This thread started when my McLeod gauge could not be shipped with its mercury. Told seller that was OK, I had found another source. Would welcome a small credit, if the drained Hg was easy for him to sell. And since the gauge had come from a transformer-processing trailer, was there related stuff for sale? Such as oil test gear, or dielectric oil itself?

Skipping to the chase -- as it turns out, the gauge seller's principal business is servicing transformers. Big ones. He's got a job coming up with some 345 kV equipment, whose oil will be cycled through his processing rig. Would be glad to tap off a gallon for my little x-ray transformer. Says it will exceed 60 or 70 kV in ASTM standard test (not that that spares me from testing it).

This isn't final yet, and of course I would pay to ship the oil. But it beats paying to ship mercury, and is more fun than buying a full 5 gallon container of Diala AX in town. Maybe I should first take the opportunity to try begging some oil from these people:

IntraWinding

Fri Dec 11 2009, 03:27PM

Registered Member #2261 Joined: Mon Aug 03 2009, 01:19AM
Location: London, UK
Posts: 581

Will you be able to trust your McLeod gauge if you use mercury of unknown purity?

klugesmith

Fri Dec 11 2009, 09:53PM

Registered Member #2099 Joined: Wed Apr 29 2009, 12:22AM
Location: Los Altos, California
Posts: 1716

IntraWinding wrote ...
Will you be able to trust your McLeod gauge if you use mercury of unknown purity?

Good question. The trusty old CRC handbook has a section about how to clean mercury for instruments, but it doesn't address the possibility of contamination by dissolved metals.

It would take a lot to substantially change the density or vapor pressure. Can easily measure the density to better than 1%. With some work I could measure electrical resistivity, which (at least in solid metals) is very sensitive to the concentration of foreign atoms. As is the melting point. 10 minutes of internet searching failed to turn up any advice on how mercury is assayed for purity.

Here is a site with lots of info about processing used Hg:

MinorityCarrier

Fri Dec 11 2009, 11:24PM

Registered Member #2123 Joined: Sat May 16 2009, 03:10AM
Location: Bend, Oregon
Posts: 312

I believe a 1mm mercury column of some length is supposed to provide 1 ohm of resistance, was used as an electrical standard. If you replicate that, you may have an idea on the purity of your batch. Otherwise, how confident do you feel about safely distilling 2 lbs of mercury?

B.T.W., drawing air through finely divided sulfer-impregnated air filters is a way to remove mercury vapor by forming mercury sulfide.

Bored Chemist

Sat Dec 12 2009, 12:15AM

Registered Member #193 Joined: Fri Feb 17 2006, 07:04AM
Location: sheffield
Posts: 1022

I wondered about making a "standard" ohm. I can get pure enough mercury but I am not sure that I could keep the temperature under good enough control.
There is a fairly simple way to clean up mercury.
Imagine you were going to put it through a simple filter paper.
So you set up a funnel and the foldeed cone of paper.
There's no way it will go through.
Punch a small hole through the bottom of the filter paper. Run the mercury through it an you will find most of the dross stuck to the filter paper.
Better cleaning than this needs a distillation or electrolytic step. That's not home chemistry from most people's point of view.

IntraWinding

Sat Dec 12 2009, 12:38AM

Registered Member #2261 Joined: Mon Aug 03 2009, 01:19AM
Location: London, UK
Posts: 581

From:
P U R I F I CAT1 0 N OF LABORATORY C H E M I C A L S
F i f t h E d i t i o n
Wilfred L. E Armarego
Christina Li Lin Chai

Mercury [7439-97-61 M 200.6, m -38.9O, b 126Â°/lmm, 184Â°/10mm, 261Â°/100mm,356.9O/atrn, d 13.534.
After air had been bubbled through mercury for several hours to oxidise metallic impurities, it was filtered to remove coarser particles of oxide and dirt, then sprayed through a 4-ft column containing 10% HNO3. It was washed with distilled water, dried with filter paper and distilled under vacuum

Rather you than me though!

klugesmith

Sat Oct 31 2015, 04:56PM

Registered Member #2099 Joined: Wed Apr 29 2009, 12:22AM
Location: Los Altos, California
Posts: 1716

I dug out that mercury after acquiring a new and pristine McLeod gauge.

Also looked into today's prices on the street. Some sellers on ebay have been getting $150/lb for triple distilled Hg in factory-labeled bottles! I hope most of them are respecting applicable hazmat shipping rules. Anybody know of private (not postal) package-delivery services with exceptions for "small quantities"? For example, in thermometers or sphygmomanometers.

Apparently it's now illegal to export Hg from most western countries. That's a consequence of the high price of gold. Mercury is in demand for small-scale gold mining by impoverished people in Colombia, Phillipines, etc. these days. The methods have shocking levels of waste and human exposure.

Last weeked I started "cleaning" the mercury in smaller bottle pictured above. About 2 fluid ounces / 60 ml / 800 grams. Should probably start a new thread, with a more appropriate title, for that story.

Yesterday I ordered a glass capillary tube to make an electrical resistance test cell. Will compare Hg from different sources, and hope to measure an improvement between samples before and after DIY purification. Could have scrounged a straight-tube thermometer. Found borosilicate tube, nominally 0.6 mm ID x 12 inches long, at McMaster-Carr. Should be about one ohm!

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