mike_au Posted August 29, 2009 Posted August 29, 2009 I've just been given a jar containing about 14kg of mercury. It has a layer of water on top of it (apparently this is to protect it, I assume from oxidation) and it has a fair bit of dirt, dust and what appear to be metal filings in it. Some float on top of the metal (but below the water) others sink to the bottom of the metal. Can anyone suggest a method of cleaning it? So far I have come up with two options: 1) Use a syringe to suck it up and transfer it to a new container, I think that if I am careful to keep the nozzle in the middle of the metal layer it shouldn't pick up too much rubbish. I don't think it should attack the plastic or rubber of the syringe but this might be a bit slow and will probably result in a fair bit of wastage.. 2) Pour it through a very fine mesh. This is probably faster but some of the contaminants might get through, the mesh might get blocked quite quickly and obviously I have to be careful what metals/alloys have been used to make the mesh. Can anyone suggest any other options or comment on the above?
a_bab Posted August 29, 2009 Posted August 29, 2009 (edited) Well, it looks like you've got something like 1 liter of heavily contaminated mercury waste. Just to start with, this amount is enough to poison forever something like an entire village. So if you are planning to make calomel out of it, I'd say forget it. You'll very likely end up dead in the process, as you are dealing with serious amounts of mercury. Giving your lack of knowledge (at least concerning the purification of mercury) + the huge amount you've got it looks like somewhere in Oz there's a disaster waiting to happen. Just think: what do you need it for? I see no use other then calomel, and this is such a no-no nowadays with the better chems we can get. If I were you, I'd get rid of it (giving it away to the authorities). Mercury waste is stored same as nuclear waste, as is persistent in the enviroment (it doesn't decompose to anything. Too bad such a nice element is so poisonous to all forms of life). Now to answer your question, a rough filtering is needed first. I'd use a cloth, that would retain the fairly large impurities. Then, there is the paper method; basically you put a small hole with a needle in a paper cone, and the mercury will slowly drip, all the oxides/impurities and some mercury being left behind. Once this is done, a wash with some kind of detergend will get it nice and clear. Working in the middle of nowhere with a big tray under the vessels to retain spills, and with 100 ml amounts at a time is a must. The cloth should be solid enough to hold big weights, and firmly nailed onto a frame (tests done before will save you a catastrophic spillage). This will only get your mercury cleaned of solid contaminants, but it certainly has something God knows what dissolved in it. In this case, a distillation/chemical purification is needed. All of these processes are very risky, even the simple cloth filtering. As you have a large amount, there will be plenty of mercuy vapors ready to poison you and other people. There is an extremly high risk of spillage, and without the proper equipment there will be certainly one (people who worked with mercury can sustain this statement). Even a mild spill (say under 10 grams) will make the house inhabitable; decontamination is extremly expensive. The mere cloth left from the "rough" purification would be a severe hazard. Think about this. Read some more stuff here: http://www.sciencemadness.org/talk/viewthread.php?tid=11652 Edited August 29, 2009 by a_bab
mike_au Posted August 29, 2009 Author Posted August 29, 2009 At the moment, I have no use for it what so ever. I would like to have a clean sample just for the novelty value but that is about it. I only really took it because it seems to be fairly difficult to get in large amounts and I didn't think the opportunity was likely to come along again. The solid impurities are all I am really worried about at the moment. It was originally from a gold mine lab so I imagine it probably has a fair amount of gold in it but I'm not going to try to get that out. I have a draeger full face respirator with a fairly comprehensive filter. I haven't checked that it is safe for mercury yet, but if not then I will get one that is. I have a reasonable sized property out in the country so I should be able to find somewhere out of the way to work with it. I understand it is extremely toxic, but I feel reasonably confident trying to clean up a small amount. Thanks for the suggestions and the link. I'll do a bit more reading tomorrow.
Swede Posted August 29, 2009 Posted August 29, 2009 I tend to agree. The metal itself isn't so bad, it is the high vapor pressure and the salts of mercury that makes it so nasty. IIRC they used to swallow mercury by the spoonful with little ill effect (!!) Sounds nuts but I believe it to be true. Before antibiotics, mercury and other metals like antimony were compounded into anti-venerials in a vain attempt to cure syphillus and a few other nasty diseases. Beyond mechanical filtration, there's little that you can do, and almost none that can be done safely. Almost everything that does not dissolve or form weird amalgams will float, so by siphoning from the bottom of the container and leaving the last 5% behind, what you siphon out should be reasonable without distillation.
a_bab Posted August 29, 2009 Posted August 29, 2009 (edited) Actually it's amazing that even nowadays there are mercury compounds that are still in use as drugs: http://en.wikipedia.org/wiki/Merbromin Mechanically filtering it would not kill you, but the risk of spillage is huge. The first thought I had when I read your thread was that such an amount could be used for gold extraction (usually one who extracts gold by the means of mercury would posess an amount of the size of an orange, which is the case. They'd filter it mechanically thru a thick dense cotton cloth by squezing the mercury "ball" out by hand). I perfectly understand you, I used to jump on such rare opportunities involving all kinds of interesting stuff too (and I still do). But when something nasty happends to you, it may become clear that after all the life is limited and what you leave behind should in no way not be a burden for your relatives. Here where I live the mercury is so banned that even something like possesing 10 grams can put one in jail. A stupid thing, I know. Edited August 29, 2009 by a_bab
Arthur Posted August 29, 2009 Posted August 29, 2009 With mercury you work over a collecting tray to catch spills. The only material that absorbs mercury is sulphur. I'm at a loss to think what impurities sink through mercury. I'd leave it sealed in it's bottle until needed.
Mumbles Posted August 29, 2009 Posted August 29, 2009 Zinc is also used to clean up mercury. It forms an amalgam.
LSchenck Posted August 30, 2009 Posted August 30, 2009 Zinc is also used to clean up mercury. It forms an amalgam. Back in the dark ages (1973) we used a device that looked very much like a large seperatory funnel with a microscopic outlet that allowed only very tiny drops of the mercury to pass through. The mercury then passed through a column of nitric acid. The cleaned mercury was collected from the bottom. This was in a clinical laboratory and we used tons of he stuff until more modern and automated chemistries replaced the manual methods. I've handled a LOT of elemental mercury over the years and somehow survived. A favorite thing in elementary school was to make a dime from a penny by rubbing it with a drop of mercury 'borrowed' from a thermometer. So much of the hysteria these days like shutting down a school because a mercury thermometer breaks in a classroom borders on bizarre. That isn't to say the salts aren't very dangerous - ESPECIALLY for small children and the unborn.
andyboy Posted August 30, 2009 Posted August 30, 2009 So much of the hysteria these days like shutting down a school because a mercury thermometer breaks in a classroom borders on bizarre. That isn't to say the salts aren't very dangerous - ESPECIALLY for small children and the unborn. Much of the things people did "back in the day" was a bit scary, although playing with mercury probably isn't one of them. Pure mercury has been used to "straighten" out volvulus (Obstructive Ileus) among other things. Swallowing a shit-load of pure mercury isn't as harmful as one would think. If the metal is left out it will turn into gas, and that's when the big problems start, that's why they have to sanitize schools for miniscule amounts.
a_bab Posted August 30, 2009 Posted August 30, 2009 I've seen a nice scenario of a thermometer breakage in a house, and the only one who'd likely suffer would have been a baby crawling on the very spot where mercury dropplets would have spilled. Other than that, everyone broke at least one thermometer in the childhood, yet he can tell the story. There is lots of media crap around the mercury as many other things. In Europe it's impossible to buy a mercury thermometer nowadays: all are digital. I actually got a mercury spill this year (from a mercury thermostat, broken by who else then my 2 years old son). The solution to the problem was: -I got a big blob from the small ones; this was difficult as the mercury got dirty and dusty, thus the globules hardly merged-I picked up the small, visible globules with a sheet of pure tin (it forms an amalgam instantaneously, just a touch is all it takes). That took like an hour-I dusted lots of sulphur over the spillage area. It takes just minutes to react with big blobs, let alone invisible vapors The mercury is said to evaporate quite fast (it does have a certain vapor pressure). I heard that an UV light source might reveal the mercury vapors (on a white screen, with a tray of mercury between the UV soource/screen). Scarry.
Pretty green flame Posted August 30, 2009 Posted August 30, 2009 In Europe it's impossible to buy a mercury thermometer nowadays: all are digital. Partly true, you can't buy mercury ones, but not all are digital. You can still buy Alcohol termometers.
a_bab Posted August 30, 2009 Posted August 30, 2009 (edited) You are right, I was thinking about the human thermometers, for which the alcohol is unsuitable due to the precision needed. Edited August 30, 2009 by a_bab
Swede Posted August 31, 2009 Posted August 31, 2009 In my rowdy, definitely kewl days, I "borrowed" a test tube of mercury from the lab. Of course it spilled in the hallway, while showing it off. The science teacher cleaned it up, and he was pi$$ed. I don't blame him at all. I was not caught, and of course the school went on as usual. We would play with blobs of mercury in science with the teacher's knowledge, and it didn't seem to be a big deal. I can easily remember my mindset from my kewl days. Things like bombs, guns, and powerful poisons like cyanide had an irresistible attraction for us, for no logical reason. I liberated a few ml of KCN solution from the lab just to have, and gaze upon. I never would want to hurt anyone, but kids' judgement sucks and accidents happen. I've always thought that stuff should not be taboo, just respected and used with supervision. That takes the mystery away, and there is less likelihood of real trouble or injury.
peedee Posted August 31, 2009 Posted August 31, 2009 In my rowdy, definitely kewl days, I "borrowed" a test tube of mercury from the lab. Of course it spilled in the hallway, while showing it off. The science teacher cleaned it up, and he was pi$ed. I don't blame him at all. I was not caught, and of course the school went on as usual. We would play with blobs of mercury in science with the teacher's knowledge, and it didn't seem to be a big deal. I can easily remember my mindset from my kewl days. Things like bombs, guns, and powerful poisons like cyanide had As a boy an irresistible attraction for us, for no logical reason. I liberated a few ml of KCN solution from the lab just to have, and gaze upon. I never would want to hurt anyone, but kids' judgement sucks and accidents happen. I've always thought that stuff should not be taboo, just respected and used with supervision. That takes the mystery away, and there is less likelihood of real trouble or injury. Totally agree Swede, if it's taboo then it's all the more interesting! As a boy I had a maze puzzle made of two round bits of plastic with a blob of mercury to guide to the centre through a passage of maze. I loved playing with that as mercury was so interesting to watch and if you shook it you could produce 10s of droplets and re-join them to one blob. Can you imagine trying to market a kids toy like that today!
Swede Posted September 1, 2009 Posted September 1, 2009 Totally agree Swede, if it's taboo then it's all the more interesting! As a boy I had a maze puzzle made of two round bits of plastic with a blob of mercury to guide to the centre through a passage of maze. I loved playing with that as mercury was so interesting to watch and if you shook it you could produce 10s of droplets and re-join them to one blob. Can you imagine trying to market a kids toy like that today! I remember that maze toy, Peedee! I had totally forgotten about it until you mentioned it. A freaking kids toy, made of flimsy plastic, with Hg in it! I love it!
peedee Posted September 1, 2009 Posted September 1, 2009 I remember that maze toy, Peedee! I had totally forgotten about it until you mentioned it. A freaking kids toy, made of flimsy plastic, with Hg in it! I love it! http://tvcream.squarespace.com/toy-list/mercury-maze.html Sorry, not sure how to do links! I can't believe I didn't take it apart eventually (memory is failing me but i did take everything else to pieces!) Hope this is not too off topic.
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