Author Topic: Mercury  (Read 1352 times)

0 Members and 1 Guest are viewing this topic.

ADDkid

  • Guest
Mercury
« on: July 07, 2004, 10:45:00 AM »
Can mercury be cleaned with jones reagent?

Rhodium

  • Guest
No, mercury is oxidized by Cr(VI).
« Reply #1 on: July 07, 2004, 12:15:00 PM »
No, mercury is oxidized by Cr(VI).


Sredni_Vashtar

  • Guest
Cleaning Hg
« Reply #2 on: July 07, 2004, 03:16:00 PM »
How is it contaminated and what do you want to clean it for?


Sredni_Vashtar

  • Guest
Cleaning Elemental Mercury Hg
« Reply #3 on: July 07, 2004, 03:43:00 PM »
These are all snipets/articles from The Society for Amateur Scientists, which I take it, most Hive members are.

**************************************
Managing Mercury

Adapted from A Thousand and One Formulas by Sidney Gernsback

Mercury is difficult to manage, on account of its weight and the ease with which it picks up impurities. Stone-ware mortars are better for holding mercury than glass beakers, which easily crack when set down. all operations with mercury should be conducted over a tray or on a table with a groove around the edge.

Dust on the surface of Mercury may be removed by allowing the mercury to run through dry filter paper in which a few pin holes have been made. Or the mercury may be washed in a current of water, and then passed through a separating funnel. The little moisture on the surface may be easily removed with a blotting paper. Many metals easily dissolve in mercury; and a very little tin or zinc will spoil its fluidity. They are best removed by shaking the mercury in a bottle with a little nitric acid; the tin or zinc will then dissove, leaving the mercury pure.
**************************************

How to Clean Up Spilled Mercury
by Robert Dean

A lot of amateur scientists store and use mercury in their laboratories. If you're one of them, it's important that you understand the dangers associated with using mercury and that you are ready to clean up a spill should one happen.

Mercury, with its high surface tension and surprisingly high toxicity should not be used or stored where it might be mishandled. In a closed room with circulating air, spilled mercury can release enough vapor to injure anyone present. Mercury droplets cannot be swept up unless the brush is soaking wet. A film of water around a drop of mercury drags it to rest and prevents it from skating all over the floor. When the droplets can no longer skate they can be brushed together and disposed of with care. After disposal of the mercury, spread "flowers of sulfur" in all the cracks where mercury might be hiding. The finely divided elemental sulfur reacts with mercury vapor to form nonvolatile mercury sulfides. Do not let mercury get in touch with Zinc, Copper, Silver, or Gold because it can form amalgams with these and several other metals and remain on their surfaces. If that happens, this surface contamination will continue to release mercury vapor into the air. NEVER USE MERCURY OVER A CARPET! A spill there and the carpet must be pulled up and disposed of as contaminated waste.

[NOTE: Those of you who store mercury, please review how you're handling it. Just as every lab should have a first aid kit, any lab with stored liquid mercury inside should have a mercury clean up kit containing a plastic dust pan and brush, a mist bottle, and powered sulfur. You can use your SAS membership to purchase powdered sulfur at a discount just by letting Nancy know that you'd like some. SC.]
*************************************

Purifying and Working with Mercury

by John Strong
Excerpted from "Scientific American's The Amateur Scientist", first published in Procedures in Experimental Physics.

Although mercury approaches the noble metals in chemical inertness, it is easily contaminated, especially by other metals. This is because, as a liquid, it is a fairly good solvent. A simple test for the purity of a sample of mercury is to raise a clean glass rod slowly up through the metal surface. If the mercury is clean, the glass will come up without any adhering mercury droplets.



The contaminations commonly found in mercury may be classified according to the manner in which they can be easily removed. First come surface contaminations by materials which do not dissolve in the liquid metal and may, accordingly, be removed by filtering the metal through pinholes in filter paper or through a chamois skin. Second, there are the dissolved metals. Those which are oxidizable are first converted to insoluble oxides by the blowing of air through the mercury as shown in Fig. 9(a). The oxides form a scum on the mercury surface and may later be filtered off. Mercury is practically free of impurities of this type if, after air has been blown through the liquid metal for two hours, no scum has formed on the surface. The alkali metals fall into this class of impurities; here also belong zinc, with a high vapor pressure, and copper and lead, with low vapor pressures. These metals, which are more reactive than mercury, can also be removed by exposing the mercury to a solution of 10 per cent HNO3 or 80 per cent H2SO4. This is shown in Fig. 9(b). Thirdly, there are the dissolved metals, such as the noble metals and tin, which cannot be removed by oxidation or acid. Copper and lead may also be considered as belonging to this class of contaminations. These metals are removed by vacuum distillation of the mercury at a temperature of about 180° to 200°C. (at which temperature the mercury distills at the rate of approximately 1/2 g/cm2/sec.) as indicated by Fig. 9(c).



The vapor pressure of mercury is given in Table I. It is to be noted thoughtfully that at room temperature the vapor density of mercury is many times greater than the accepted nonpoisonous concentration limit, which is 1 milligram of mercury per cubic meter. According to Stock, continual breathing of air containing only 15 micrograms per cubic meter of mercury for a few weeks will make most persons ill. The vapor pressure of mercury is hazardously high in many laboratories. In a Berlin physical laboratory the typical concentration of mercury vapor in the air was found to be about 20 to 60 micrograms per cubic meter; in one room it was 500 micrograms per cubic meter. Heat produced by turning on mercury pumps doubled the concentration of mercury vapor in the air.

*************************************

LN2: Secrets of Zone Purification

by Shawn Carlson

One of the most useful ways to remove impurities from a liquid is to freeze it in a controlled way. Suppose, for instance, you want to purify some mercury you've got laying around. You could distill it, that is boil it and then condense the vapors. But since even a tiny concentration of mercury vapor is toxic, it's not a good thing to be boiling in your laboratory. But a good solution for the home scientist is to go to the other temperature at which mercury changes state, namely it's freezing point. As a general rule, a pure liquid freezes at a higher temperature than a contaminated one (that's why they sprinkle salt on roads in the winter time). So as heat is removed from a freezing liquid the pure molecules tend to bond together first, concentrating the impurities into the liquid that remains. So if you place a test tube of mercury into a bath of dry ice and alcohol, the mercury will freeze first around the inside of the tube, concentrating the impurities into the center. If you pour off the center fluid when about half of the volume is frozen, the mercury that remains will be substantially purer than what you started with.


ApprenticeCook

  • Guest
wash with water and strip off mercury in sep...
« Reply #4 on: July 11, 2004, 08:50:00 AM »
wash with water and strip off mercury in sep funnel, or organic solvent if contaminated with organics, neither of which will bother the mercury (water or toluene/xylene).


Sredni_Vashtar

  • Guest
Clean mercury
« Reply #5 on: July 12, 2004, 04:57:00 PM »
If you want to make a cheap, accurate manometer, you need clean mercury with no contaminants. Best is fresh, triple distilled mercury.

If you want to make mercury salts, then purity is less of an issue. Would you even bother washing unless you had reason to believe the mercury was contaminated?


armageddon

  • Guest
hm
« Reply #6 on: July 12, 2004, 06:01:00 PM »
Please think about your health when handling mercury - Wear gloves, safety goggles, lab coat - ONLY USE LABORATORY GLASSWARE, NO FOOD JARS/KITCHEN EQUIPMENT ETC. - cover spillover areas immediately with sulfur powder (after taking up visible droplets), work only under fume hood (if you have the possibility), NEVER breathe ANY mercury fumes when distilling it!!!

(mercury might be useful, but it is a deadly poison, and even exposure to lower concentrations over prolonged time periods is very dangerous, as mercury accumulates in the body and if the toxicity threshold is reached, the victim slowly suffers from increasing INSANITY - not the nicest death if u ask me)

Greetz A


Sredni_Vashtar

  • Guest
True, mercury is nasty
« Reply #7 on: July 12, 2004, 06:15:00 PM »
I read recently that mercury is excreted by the body and is not a cumulative poison below certain levels. Can't find the article just now...google dominated by quack noise.

In the middle ages, mercury was used to treat a twisted bowel: drink half a pint and rely on gravity and peristalsis to sort the problem out. Liquid mercury isn't regarded as that much of a hazard - you wouldn't notice any effects from swallowing a small amount of metallic mercury. I've stuck my fingers in mercury a few times, but only a few times. I don't leave it open to the air and I don't let children or anyone who might have a bun in the oven anywhere near the stuff.

Mercury vapour is dangerous and has been covered before. Always use a tray etc. If you spill metallic mercury on floorboards, carpet etc., then you have made a serious and avoidable mistake. Don't spill it. It is easy not to.

Mercury salts are different, of course. Deadly toxic.


ApprenticeCook

  • Guest
Sredni - when i was talking about cleaning the
« Reply #8 on: July 12, 2004, 10:23:00 PM »
Sredni - when i was talking about cleaning the mercury i meant for making the salts, Hg from 90c thermo's is easiest and safest to get but you get shitloads of glass fragments in it when you bust them....

that said, method to bust them...
Get a GLASS non-food jar (ie you dont ever want this jar again...) that will fit the length of the thermos, buy a few thermos 3 will do, and put them Hg end down in the jar, seal and tape it up with some duct tape, then shake the shit out of it, the thermos will break and release the Hg into the jar.
Leave it to sit for ~10min to allow any Hg on the walls to fall down. Open the jar and with gloves remvoe the remains of the thermo, dont try and pick up glass pieces only the large stem that has the numbers on it. Then wash the Hg as it contains small glass bits.

But to wash for chemical impurities your method good, i was only talking about physical impurities as i have said above.

But yes, anyone who doesnt know the dangers of elemental Hg and the high toxicity of Hg salts is in for a set of huge problems, care must be taken.

-AC


hypo

  • Guest
i love repeating the same shit again and again...
« Reply #9 on: July 13, 2004, 12:22:00 AM »
> when i was talking about cleaning the mercury i meant for making
> the salts, Hg from 90c thermo's is easiest and safest to get but
> you get shitloads of glass fragments in it when you bust them....

this is the last time i'll say it: go to a big electronics store,
buy the biggest mercury switch, scarify it with a glass cutter and
break it open. for the price of a thermometer you'll get much more
Hg and no glass fragments.

as for glass fragments: why even care? glass is perfectly inert
(you're doing your reaction in glass, yes?). during the process,
at one point everything is in solution, right? just filter it then,
or combine with a flitration where you discard the filter cake.
(btw: iirc the filtercake of the HgCl2 preparation can be reused,
but you'll get more than enough HgCl2 anyway...)

ps: while you're at the electronics store, get some super cheap
sodium persulfate, this will spare you doing chemical engineering
in your kitchen...






Sredni_Vashtar

  • Guest
Mercury Sources
« Reply #10 on: July 13, 2004, 08:23:00 AM »
Barometer spares suppliers are good for clean mercury - bit of a mark-up on chemical supplier prices though. (Seen it for around 20 Euros for 500 g.)


ApprenticeCook

  • Guest
hypo, either way, thermo or mercury switch....
« Reply #11 on: July 13, 2004, 11:21:00 PM »
hypo, either way, thermo or mercury switch.... thermo is cheap and gets ~0.4g Hg from each and Hg switch is a little more costly and you prob get about double the amount of Hg from it?? ~0.8g?? either works fine....

and as for removing the glass i was only talking about the pieces you can see for purely aesthetic reasons, there will be heaps of glass dust and small fragments in there from the bulb breaking, which are not too easily removed... in my Hg you can still see heaps of dots but as you said, glass is inert so it doesnt matter for our use...

Which ever way depends on how much the Hg costs per gram... varies with shop and location as to prices of thermos and Hg switches.

-AC


hypo

  • Guest
wrong
« Reply #12 on: July 14, 2004, 01:25:00 AM »
15-20g from the big ones.
and there will be _no_ glass if you use a glass cutter and break it open cleanly.


Sredni_Vashtar

  • Guest
Lets not bitch
« Reply #13 on: July 14, 2004, 04:21:00 PM »
They're both good sources, it depends what you have available locally and how much you need. Hypo is probably correct on best economy. Thing is, for making HgCl2, you only need a few grammes. You can get tilt switches in the UK, but there is a move away from Hg switching mechanisms, like all uses of mercury. Mercury is also good for manometers - this works well. I was thinking about using vacuum pump oil - less dense and greater precision perhaps - has anyone tried? I've been looking for cheap piezo absolute pressure transducers with no luck and settled on an Hg U-tube as the best solution. Anyone done better? It's as cheap to get the full works from Conrad.de as build your own electronic gauge.


ApprenticeCook

  • Guest
20g Hg !!! crap... ok well if you need that...
« Reply #14 on: July 14, 2004, 09:38:00 PM »
20g Hg !!! crap... ok well if you need that much guess thats what you buy then...

I only get enough Hg to make the right amount HgCl2 i need at that time, i dont like storing the stuff.

-AC


flnvaz

  • Guest
Help
« Reply #15 on: July 15, 2004, 10:33:00 PM »

ApprenticeCook

  • Guest
www.rhodium.ws/chemistry
« Reply #16 on: July 15, 2004, 11:30:00 PM »
ffs,

is it that hard?
look at rhodiums site, scroll down till you find the mercury salts synth...

-AC