Caver451 Posted January 13, 2006 Share Posted January 13, 2006 Hello! I have some samples of depleted uranium for my element collection. When the samples arrived, I became a bit concerned about how they were stored. Supposedly, under argon, but they have a relatively heavy layer of oxidation. I moved one of the two samples to a small glass vial under mineral oil (heavy, USP) to hopefully stop any further oxidation. The samples are each over 2 grams. Uranium oxide is much more toxic than uranium metal, so I'm a bit wary about trying to remove it from the samples. That said, any advice on doing this? Under mineral oil (of course!) with a brass or aluminum brush? I don't want to scratch the uranium metal underneath, so I should probably avoid steel brushes. Any pitfalls I can expect? Is USP grade heavy mineral oil acceptible for storage of the uranium metal? I can't imagine it wouldn't be, but I don't want to make the situation worse! I have no way of getting argon over the oil. Thank you for any advice or hints! I've included a small photo of one of the samples out of the packaging as I was weighing it. Notice the black oxide flaking off on the right side. -Caver Link to comment Share on other sites More sharing options...
DV8 2XL Posted January 13, 2006 Share Posted January 13, 2006 The stuff will oxidize on contact with air so mineral oil is probably the best choice. I wouldn't try to clean it as the oxidation layer can go quite deep. In fact the oxide will flake off by itself and the process will continue untill the sample is gone. Link to comment Share on other sites More sharing options...
YT2095 Posted January 13, 2006 Share Posted January 13, 2006 I have no way of getting argon over the oil. yes you do, go and buy a bottle of it from the Welding section in a hardware store, it`s used all the time regularly in MIG welders Link to comment Share on other sites More sharing options...
jdurg Posted January 13, 2006 Share Posted January 13, 2006 Uranium metal is VERY easily oxidized and is a royal pain in the arse to store because of that. It's a lot like the alkali metals in regards to how quickly and readily it will oxidize thanks to atmospheric oxygen/water. No matter what you do, it will darken and become covered with the black oxide layer. (I have run into the same problem with my metal chunk and turnings). For storage, your best bet is to get a tightly fitting borosilicate glass vial and completely submerge your uranium under mineral oil. If the entire vial is filled with oil there will be very little room for oxygen to get inside the vial. In addition, you'll need to ensure that the cap is sealed as tight as possible. Using a silicon caulking to permanently seal the vial shut may not be a bad idea. My uranium metal is stored in a small 20 mL glass vial whose threads are wrapped in Teflon tape and whose volume is completely filled with mineral oil. I then have it stored in a wooden box lined many times over with lead sheeting. Also, don't worry about scratching your uranium. Uranium metal is VERY solid. I.E. it doesn't scratch easily at all and is a very hard metal. Moving it over with steel tweezers isn't going to damage it at all. Link to comment Share on other sites More sharing options...
Caver451 Posted January 13, 2006 Author Share Posted January 13, 2006 Wow, lot's of super good information, thanks everyone! DV8 2XL> I noticed, unfortunately! Can "how quickly" be quantified somehow? Would bare metal visibly blacken within seconds, or would it potentially take several minutes before the corrosion becomes visible? YT2095> I am sooo tempted to build a dry box, which would likely make it much easier. Especially when I decide to start swapping around samples! jdurg> Does the type of glass vial matter? If the metal is completely submerged in the mineral oil, what action causes the remaining air above the oil in a closed vial from getting to the metal? It sounds like you talk from some serious experience! I'm a bit new at this. I haven't started collecting the alkali metals yet, but it is definitely my favorite group and I am looking forward to starting. I just couldn't pass up on the uranium--it doesn't strike me as something that just pops up every day. Ironic, since so much of the stuff is produced... I want to get this whole mess of protecting my samples figured out before I start investing in elements I will end up having to replace later due to improper storage. Would building a dry box seem like a good idea? Any good sources of information on the technical "preservation" aspect of element collection available? How about "build your own" drybox design? Perhaps THAT is a separate thread! Thank you again for all of the incredible feedback so far! I think I found a new home! With interests ranging from several disciplines of physics, chemistry, and biology... I think I may well have found heaven! -Caver Link to comment Share on other sites More sharing options...
DV8 2XL Posted January 14, 2006 Share Posted January 14, 2006 Depends on conditions like temp, humidity and the crystal structure of the metal what what trace contaminants are in your sample. Link to comment Share on other sites More sharing options...
jdurg Posted January 14, 2006 Share Posted January 14, 2006 Hey no problem. When having an element collection the proper storage of your samples is FAR more important than anything else. As you said earlier, what good is a sample if it will corrode away to nothing in a short while? With Uranium the oxidation happens a bit slowly. I liken it to the oxidation of calcium metal. You can cut a piece off and it will show as a silvery metal, but after a little while you'll see it getting dull, then after a few hours it will be black. Even under oil it will blacken as time goes by. The piece I have was cut right in front of me, but in the amount of time it took for me to get back home (About an hour), the fresh silver surface of the Uranium had oxidized and become dark gray. It's now an iridescent black like the rest of the surface. For the glass, I use borosilicate glass in all of my element containers as it is a strong glass, doesn't really allow too much air through it, and it doesn't expand or contract a helluva lot as the temperature changes. If you fill a vial with oil, however, over time air will seep in and oxidize your sample. It doesn't really matter how well you seal it. You can only slow down the oxidation. So the oxidation of your Uranium is just something you'll have to accept. It's like the oxidation of Europium. Unless you can seal it in a glass ampoule in a dry box there will always be SOME oxidation on it. What I would do is take the vial and put the Uranium in there, then fill it to the top with the oil. Wrap the threads of the vial with some Teflon tape and be sure to wrap the Teflon around the threads moving clockwise. Now screw the cap on as tight as you can. Don't be afraid to use a good deal of force, but also don't use so much that you break the glass. With the cap tightly put in place, you can take some waterproof caulking and put a bead of sealant where the cap meets the vial. This will seal off the opening and prevent any air from getting in. While it will also make it so that you really can't open your container again, it will keep it sealed. Finally, wrap a layer of electrical tape around the top of the vial. The Uranium will react with any of the oxygen dissolved in the mineral oil, but if you poured it in there from a new bottle there shouldn't be a lot of dissolved O2, and if the vial was filled to the top with the oil there won't be a lot of airspace in the vial which would allow the O2 to dissolve. The biggest thing to remember is to keep some lead shielding around your uranium so that you aren't contanstly being exposed to the radiation. Depleted Uranium is moderately weak in terms of strength and DU that's at least one year old will have the same level of radioactivity for the next few thousand years. (As it takes quite a bit of time for the decay products to build up. During that first year, the Thorium and Protactinium are able to build up and add a tiny bit of radiation to your sample, but nothing earth shattering). All it takes is a few thin sheets of lead sheeting to block the radiation. So if you have a wooden box you can line it with a few layers of lead and everything will be fine. A good test to see if your shielding is effective is to take some unexposed polaroid film sheets and leave them, still sealed, around your Uranium container. After about a month of being next to your Uranium, develop the film. If your shielding is working you'll see nothing but a black photograph. If there is some "leaking" you'll see a hazy, fuzzy area where the gamma rays and generated x-rays were getting to the film. Collecting elements is a fun, but expensive and time consuming hobby. It's kind of sad when you finally get that last sample and have no more to collect. I have my collection hosted online at http://www.chemicalforums.com/~jdurg/FullPTP.zip, so feel free to take a look if you'd like. If you have any questions, please don't hesitate to contact me. Link to comment Share on other sites More sharing options...
DV8 2XL Posted January 14, 2006 Share Posted January 14, 2006 Lead? A sheet of paper will stop anything coming off a chunk of DU. If it's under oil and in a glass container you have nothing to worry about. Link to comment Share on other sites More sharing options...
jdurg Posted January 14, 2006 Share Posted January 14, 2006 Uranium gives off gamma rays in addition to the alpha particles, and a piece of paper isn't going to stop the gamma rays. I guarantee you that. Link to comment Share on other sites More sharing options...
DV8 2XL Posted January 14, 2006 Share Posted January 14, 2006 I wouldn't worry too much about gamma from a small sample. Anyway even that attinuates very rapidly with distance. Link to comment Share on other sites More sharing options...
jdurg Posted January 14, 2006 Share Posted January 14, 2006 It's a similar analogy to saying "I don't need to wear sunblock because I have a dark tan". Yeah if you have dark skin you won't burn as easily, but exposure to those ultraviolet rays still aren't a good thing. The same is true with gamma rays. Yeah they might not be super strong, but why increase your exposure when there is no need to? The amount of gamma rays given off is directly proportional to the surface area of your sample. If you have a small cube, then there won't be nearly as many gamma rays given off as a similarly massed thin sheet. (As the high density of the uranium does a damned good job at blocking radiation). Lead sheeting is not expensive at all and the extra protection it provides is a must. Short term exposure won't do much to you, but if this uranium is a part of your collection and it will be around you for a good long period of time then you must minimize the exposure. Link to comment Share on other sites More sharing options...
DV8 2XL Posted January 14, 2006 Share Posted January 14, 2006 Whatever helps you sleep at night. I suspect though that you are probably exposed to more gamma during the course of the day from incidental sources that you would be from your element collection. Link to comment Share on other sites More sharing options...
Caver451 Posted January 14, 2006 Author Share Posted January 14, 2006 Lead sheeting is not expensive at all and the extra protection it provides is a must. Short term exposure won't do much to you, but if this uranium is a part of your collection and it will be around you for a good long period of time then you must minimize the exposure. I have lead sheeting, and I'm in the process of building a proper hot box. With anything even remotely dangerous, I always err on the side of offering more respect than might be required. I would rather know I have more protection than I need, than think I have enough when I really don't. Besides, if anything, the box will be a conversation piece. I'm still debating whether or not I should remove the uranium oxide from the samples and then seal them up nice and secure like jdurg recommended. I'm beginning to lean towards DV8 2XL's advice and not bother removing the oxidation. It seems we've established that unless I seal the sample in a glass ampule under low pressure argon, I'm going to be struggling with the problem anyway. And the less contact with the highly toxic uranium oxide I have, the better. jdurg, I looked at your element collection... VERY nicely done! -Caver Link to comment Share on other sites More sharing options...
jdurg Posted January 14, 2006 Share Posted January 14, 2006 Actually, the hot box is a nice little conversation piece. When I show people the uranium portion of my collection, it's always fun pulling out the stained and varnished box, then opening it up, removing the lead covering, then pulling out the vial with the uranium in there. What I will eventually plan on testing out with my lanthanum and neodymium samples is removing the oxidation from a part of it, then painting the metal with a clear lacquer that will adhere permanently to the metal's surface. This way a portion of it will be forever protected against oxidation but a part of it will also show the characteristic oxidation colors. The problem is finding a lacquer that will dry incredibly fast and also not dissolve away in the mineral oil that the metal is stored in. With the uranium, you are better off not removing the black oxide layer because the chance of spreading low level radioactive waste is pretty high if you are removing the "tarnish" from the metal's surface since the "tarnish" itself is mildly radioactive. After a while, the blackened surface takes on an odd iridescent coloring which is pretty neat to see. (This is really showing up on the turnings I have). Oh yeah, thanks for the compliment. It took quite a few years to put it together and more money than I'd care to think about, but it does feel good to see it complete. At this point it's just a matter of upgrading samples, preserving other samples, and increasing the amounts of certain samples. If I can give any advice about element collecting it would be to take advantage of every opportunity you get. If a sample suddenly becomes available to you, purchase it. If I didn't follow that advice I never would have gotten my white phosphorus, red phosphorus, cesium, rubidium, uranium, rhodium, arsenic, etc. for the prices that I did. If you ever have any questions, feel free to ask them here or if you'd like you can send me a PM if you don't want to post on the forums here. Link to comment Share on other sites More sharing options...
DV8 2XL Posted January 14, 2006 Share Posted January 14, 2006 Look into some of the clear UV curable lacquers. I use them extensively at work and they cure in about five seconds flat under short UV. With a total seal you wouldn't need the oil. Link to comment Share on other sites More sharing options...
jdurg Posted January 14, 2006 Share Posted January 14, 2006 Look into some of the clear UV curable lacquers. I use them extensively at work and they cure in about five seconds flat under short UV. With a total seal you wouldn't need the oil. I'll have to look into that. I do want some of the metal to be oxidized and I'm not sure how well the lacquer would adhere to the spalling oxide. That's the reason for keeping it in the oil. I just think it would be really incredible looking to have half the ingot be a bright metallic surface while the other half has oxidized to the typical oxide color. (It'd be really neat to paint on there the name of the element so that when it all oxidizes again only the element name would be non-oxidized.) Link to comment Share on other sites More sharing options...
DV8 2XL Posted January 14, 2006 Share Posted January 14, 2006 The stuff will stick to ANYTHING. Anyway if you encapsulate it it won't matter. The cured material can be super hard (it's used for dental work too) IF you pick the right variety. Link to comment Share on other sites More sharing options...
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