| Pages:
1
2
3 |
Dr.Bob
International Hazard
Posts: 2732
Registered: 26-1-2011
Location: USA - NC
Member Is Offline
Mood: No Mood
|
|
Plastic id much more air permeable than glass, that is why soda goes flat in plastic quicker than glass, and each type of plastic is different in what
goes through it faster. But if you put the plastic bag in a glass jar and seal it, it will help a lot, especially if you can purge it with argon
first. Helium diffuses much faster than argon, so argon is better.
No metal will last forever if not sealed well, but a layer of surface tarnish will not be a big issue for most chemistty, I have used lousy looking
sodium and it works just fine. The only time the appearance will matter is for use in pretty element displays, and that will require a sealed ampule
or glass jar full of oil to really keep the metal clean.
|
|
|
careysub
International Hazard
Posts: 1339
Registered: 4-8-2014
Location: Coastal Sage Scrub Biome
Member Is Offline
Mood: Lowest quantum state
|
|
The Balloon Time MSDS claims that their product is 100% helium:
http://www.balloontime.com/about/warnings-precautions.aspx
Frankly I am dubious.
I expect they are filling welding helium which has a minimum purity of 99.995% into a tank that already contains air. The tank has a pressure of 260
PSI, so this would result in 95% helium, 4% nitrogen and 1% oxygen.
The Bloxygen people are selling their product specifically as an inert gas, so I believe they have a pure argon product.
Quote: Originally posted by The Volatile Chemist  |
Couldn't you just fill a jar w/ a nonreactive oil, plop the lithium in, close the jar, then flip it upside-down? I guess that defeats the ease of
using it, though.
Sounds like you got a pretty big lot of lithium! Where'd you get it? |
Yes, the inverted oil jar is something I am considering (I mentioned it above), but if it has a gas space it still needs to be flushed.
What is a "big lot" of lithium? I have 50 g right now, bought at a good price of eBay. There is a Chinese vendor offering 25 g for $20, of $0.80 per
gram. GalliumSource charges $1.10 per gram on amounts of 100 g.
When you consider the price per mole, that is $5.50/mole. Someone on this site is offering sodium at $100/lb which works out to almost the same:
$5/mole. If you need an alkali metal for a reduction the lithium is attractive.
The lithium though is special case of a more general problem (storing air-reactive materials) and there are more than a few of those in a complete
element collection, so the merits of various options is of interest to me.
I think I am going with putting the inner bags of lithium in an argon-flushed mason jar, with PTFE tape on the threads, and heated to activate the
rubber seal (I'll experiment with some empty jars first.)
Hmm.. I do have a partially used old BalloonTime tank. Perhaps I should pre-flush a storage jar with the no-doubt air contaminated helium to get some
use out of it, then flush with Bloxygen argon.
For an element display lithium in an inverted mineral oil filled culture tube (with screw cap) would be good. Seal the cap (after tightening) with
silicone perhaps?
[Edited on 5-9-2014 by careysub]
[Edited on 5-9-2014 by careysub]
|
|
|
The Volatile Chemist
International Hazard
Posts: 1981
Registered: 22-3-2014
Location: 'Stil' in the lab...
Member Is Offline
Mood: Copious
|
|
I was talking about Leben's 500g. But I didn't know it was that cheap. | Quote: | | Yes, the inverted oil jar is something I am considering (I mentioned it above), but if it has a gas space it still needs to be flushed.
|
Just do it in a basin of oil, with the jar submerged. I suppose silicone and many other thins would work.
|
|
|
MrHomeScientist
International Hazard
Posts: 1806
Registered: 24-10-2010
Location: Flerovium
Member Is Offline
Mood: No Mood
|
|
careysub, I also bought lithium from that supplier and received it a couple days ago. How was the quality of yours, when you first
removed it from the package? Mine was already pretty tarnished. Still decent looking, but nowhere near the quality of the listing's picture. I also
got two bags - one was packaged as you described, and the other has both outer and inner packages as the metal foil. I'm hoping the inner foil packet
holds up better than the clear plastic one. I wanted at least one of these for a high quality element display :/
|
|
|
careysub
International Hazard
Posts: 1339
Registered: 4-8-2014
Location: Coastal Sage Scrub Biome
Member Is Offline
Mood: Lowest quantum state
|
|
| Quote: Originally posted by MrHomeScientist | | careysub, I also bought lithium from that supplier and received it a couple days ago. How was the quality of yours, when you first
removed it from the package? Mine was already pretty tarnished. Still decent looking, but nowhere near the quality of the listing's picture. I also
got two bags - one was packaged as you described, and the other has both outer and inner packages as the metal foil. I'm hoping the inner foil packet
holds up better than the clear plastic one. I wanted at least one of these for a high quality element display :/ |
I ordered two, both came with the foil outside packet, with the clear tear-open style packet (discovering this requires sacrificing the outer packet
obviously).
Both were bright and shiny as received.
I currently have them both in a quart mason jar that I flushed with Bloxygen argon gas. The new bag went in day before yesterday.
One problem with the Bloxygen, is I am uncertain if I have flushed enough. The jar is 1 qt, the can holds 6.7 L of argon. I guess I should just empty
the rest of the can into it, and time how long that takes, then I would roughly know the rate of emission (I will have to estimate my time for the
first flush) for future possible use.
I just found Bloxygen cans are available for $8.50 at Austin Hardwoods in Santa Ana, CA.
If I feel the need to buy more than a couple of cans I should invest in a 15 lb gas cylinder and get argon from Praxair. They may be in my future if I
work with reactive substances much.
|
|
|
MrHomeScientist
International Hazard
Posts: 1806
Registered: 24-10-2010
Location: Flerovium
Member Is Offline
Mood: No Mood
|
|
So I also bought some of the Chinese lithium (2 orders of 25g each), and it was packaged as one envelope with two metallic packets inside. In the
first metallic pouch was a second clear plastic pouch that contained the Li metal. The other metallic pouch contained a second metallic pouch that
feels like it contains the metal (this one isn't transparent). The metal I received was significantly tarnished from the minute I got it, after
opening the outer packet but leaving the inner clear plastic one intact. It wasn't terrible, but wasn't nearly as clean as the listing's picture
claimed. I tried complaining to the seller but, predictably, he replied with poorly translated gibberish like "Dear friend. Pretty only 96.5% purity
lithium lithium is you receive a high purity. I hope you understand."
So I ordered a couple cans of the Bloxygen stuff careysub mentioned to try to save it - really great find by the way, thanks a lot
for that tip. It took about a week to arrive, and all the while the lithium in the plastic pouch continued to tarnish despite being completely sealed.
When I got my Bloxygen, I fumbled around a bit but managed to get it all in a pyrex media bottle that I had purged with Bloxygen argon. I sealed the
cap with yellow gas-tight plumber's teflon tape, and wrapped the outside with parafilm for good measure. Not sure if parafilm does much of anything,
but it couldn't hurt. Anyways here's a picture of what I've got now. Still slightly shiny but quite blackened. I'm very surprised how permeable that
plastic packaging was, and how quickly the Li has darkened.
That's one of the 25g packets. The other portion is still in its inner metallic pouch, which I hope holds up better than the clear plastic one did.
I'm trying to find a more permanent storage solution for that batch, and one which will look nice for display in my collection (assuming that pack is
less tarnished).
|
|
|
Dr.Bob
International Hazard
Posts: 2732
Registered: 26-1-2011
Location: USA - NC
Member Is Offline
Mood: No Mood
|
|
Having done a lot of work with reactive chemicals in my days, I can say with great assurance that nearly any container with a closure (lid, cap, screw
top, etc) will leak some amount of air and water through it. Also, any polymer will let various amounts of both through, some are better at
resisting water or airt than others, but few plastics are very resistant to water and air permeation at the level needed to protect reactive metals.
A glass ampule is really the best solution to keeping chemicals fresh that I have seen, I have handled chemicals in ampules that might have been 10-20
years old that still looked fresh and clean. Comparably, still sealed glass bottles, never opened, have shown large amounts of reaction after
periods of days to years, depending on the closure.
But a simple jar full of mineral oil will suffice for most storage of reactive metals being used for chemistry, as the oxide/nitride layer will not be
a big issue for most chemistry that I have ever seen. Making sodium methoxide, for instance, most people just cut a clean chunk or several (if the
scale is big, you may need to use a lot of smaller pieces), then add it slowly to the methanol (under argon) or put it in a flask with an inert
solvent and slowly add the methanol to it. For the chemistry I have done, that provides perfectly good NaOMe, even with bottles of sodium that look
20 years old.
|
|
|
jamit
Hazard to Others
Posts: 375
Registered: 18-6-2010
Location: Midwest USA
Member Is Offline
Mood: No Mood
|
|
Hi careysub and mr homescientist -- I also ordered from the Chinese supplier and just as pictured by homescientist, it comes already tarnished with
the black crud. Has anyone tried melting it?
|
|
|
careysub
International Hazard
Posts: 1339
Registered: 4-8-2014
Location: Coastal Sage Scrub Biome
Member Is Offline
Mood: Lowest quantum state
|
|
| Quote: Originally posted by jamit | | Hi careysub and mr homescientist -- I also ordered from the Chinese supplier and just as pictured by homescientist, it comes already tarnished with
the black crud. Has anyone tried melting it? |
I guess I got lucky with my two shiny samples.
I am considering melting it into ampoules, or a test tube for storage, but I plan on getting a regular argon gas bottle first so that I can purge to
my hearts content - even purge a small handling box for when I crack open my Mason jar.
I figure than if you put all the lithium in a test tube/culture tube and melt it down it will stick to the glass and stay on the bottom. Then pour in
a little degassed mineral to fill to the top and seal.
|
|
|
MrHomeScientist
International Hazard
Posts: 1806
Registered: 24-10-2010
Location: Flerovium
Member Is Offline
Mood: No Mood
|
|
Doesn't molten lithium react with glass? Very quickly?
Edit:
Found this document detailing precautions when handling lithium. It doesn't mention the glass reaction (even though the google link to it says it
does), but I did see this interesting bit:
"The reactivity of molten lithium is much greater than solid lithium. Blanketing with argon or dry air is recommended to
protect the metal and to minimize the possibility of fires. Molten lithium reacts explosively with concrete flooring, and any area
wherein a liquid lithium spill may occur must have welded steel flooring."
That sort of puts a damper on my planned experiments on the back porch.
[Edited on 9-25-2014 by MrHomeScientist]
Attachment: LithiumHandlingURC.pdf (14kB)
This file has been downloaded 596 times
Edit 2:
Here we go:
Attachment: The Alkali Metals.pdf (3.9MB)
This file has been downloaded 936 times
From that source:
[Edited on 9-25-2014 by MrHomeScientist]
|
|
|
careysub
International Hazard
Posts: 1339
Registered: 4-8-2014
Location: Coastal Sage Scrub Biome
Member Is Offline
Mood: Lowest quantum state
|
|
I guess I won't be melting my lithium in a test tube then!
I see that molten lithium does not react with "low carbon stainless steels". Also, it doesn't react with tungsten or moylbdenum.
I guess I can cast my lithium into an ingot using a stainless steel mold, in a stainless steel, argon-flooded crucible. The coefficient of thermal
expansion of lithium is about 46*10^-6 k, over 4-6 times larger than stainless steels so the lithium should separate from the mold on cooling.
You could cast a piece of stainless steel, Mo or W into the lithium ingot as a permanent anchor, and have the mystery of the sinking lithium to puzzle
your friends.
|
|
|
MrHomeScientist
International Hazard
Posts: 1806
Registered: 24-10-2010
Location: Flerovium
Member Is Offline
Mood: No Mood
|
|
I had planned on using my lithium for the final stage in my 'neodymium from magnets' project, by mixing it with NdF3 and heating in a crucible. The
only crucible types I have are fused silica (probably no good because of the whole 'glass reactivity' thing) and graphite. I'm wondering about
graphite now, since low carbon steels was mentioned. What happens when it's all carbon? The last thing I'd want is to form lithium carbide which could
produce acetylene and explode my furnace 
I do have stainless steel condiment cups, perhaps that's an option?
|
|
|
Dan Vizine
National Hazard
Posts: 628
Registered: 4-4-2014
Location: Tonawanda, New York
Member Is Offline
Mood: High Resistance
|
|
I've had a bit of experience handling molten lithium. At low temperatures (say, <500 C), you can use many common metals for molten lithium. I've
used SS in the 300 series, like 302, 304 & 316, as well as mild steel.
No commonly available ceramic or glass is appropriate. Yttria stabilized thoria is the best ceramic, with only minor attack after 1000 h @ 1093 C.
Sample Temp (C) Time (hr) Results
BeO 1093 500 Significant attack, Li penetration
MgO 1093 100 Disintegrated
Y2O3 1093 1000 Slight attack
ThO2 1093 1000 Slight attack
ThO2 -5% Y2O3 1093 1000 Very minor attack
AlN 1093 1000 Severe cracking
BN 1093 100 Disintegrated
TiC 1093 2000 Some cracking
MgAl2O4 1093 100 Disintregated
At elevated temperatures, the situation changes a bit:
Lithium—a vessel fabricated in the 1970’s of RA333 for the US Navy liquid metal
embrittled & cracked from residual stress in the formed head, when operated 1650°F
(900°C) with molten lithium. Had we been asked, we would have suggested first annealing
the head to remove forming stresses. Corrosion of RA333 occurs primarily by selective
leaching of the nickel. Alloy X behaves in a similar manner. Based on laboratory tests,
TZM molybdenum and pure iron (to 1000°C) are said to have good resistance to molten
lithium corrosion. Ferritic stainlesses are said to be subject to chromium leaching.
However E-Brite was found more resistant to molten lithium than either nickel or cobalt
base alloys. These are laboratory test results, not necessarily confirmed in service.
I've attached a small collection of references which deal with lithium. There is a lot of practical information sprinkled throughout.
Attachment: Lithium & Ceramics.PDF (35kB)
This file has been downloaded 437 times
Attachment: Lithium Combustion.pdf (2.9MB)
This file has been downloaded 581 times
Attachment: Lithium Handling.pdf (64kB)
This file has been downloaded 907 times
Attachment: Lithium Properties.pdf (3.2MB)
This file has been downloaded 681 times
And, here's a quote from "The Encyclopedia of Chemical Elements" by Clifford Hampel and published in 1968 by Reinhold.
"Lithium can be melted and poured in dry air without losing its luster and it does not react with dry oxygen below 100 C"
With lithium, its ALL about the moisture. Without catalysis by 5 ppm or more H2O, Li is indifferent to both oxygen and nitrogen.
At high temperatures, lithium reacts with elemental carbon to give the acetylide. Exactly what constitutes "high" wasn't specified in the above
encyclopedia, although the definition that is generally accepted now is that anything above 500 C is a high temperature process.
A note about storage...no plastic will keep lithium shiny for long. It's because of what makes plastics plastic, the long chains, loosely organized at
best, just can't stop oxygen diffusion. Only metals, glass or metallized plastics will work. And speaking of work, if it's got a screw cap, it won't.
Or not for long anyway. The unstoppable force of diffusion never gives up, and so, oil or no oil, lithium in a screw cap bottle eventually darkens.
Always. Only a "total" seal, like an ampoule or the heat-welded metallized bag that it comes in, is good enough for long term storage.
There isn't a real danger of molten lithium - concrete explosions unless you have a whole lot of liquid metal. Otherwise it just splashes like solder
does, and it cools quite quickly. I've done it more than once.
Another noteworthy factor when melting Li in air, once a nucleus of this cauliflower-looking solid mat (a mixture of the nitride and other species)
forms on the surface of the liquid metal, fire is going to happen. This is catalysis out of control. It's not a big deal (not a flash), except that
it's very, very difficult to extinguish. Carbon powder is suggested, but I usually just let it burn and turn the exhaust fan on. The amounts that I
melt are modest, usually just 5 - 20 g at a time.
[Edited on 16-10-2014 by Dan Vizine]
|
|
|
MrHomeScientist
International Hazard
Posts: 1806
Registered: 24-10-2010
Location: Flerovium
Member Is Offline
Mood: No Mood
|
|
Fantastic info Dan, thanks very much for posting. I'm reading through the attachments now. So you've used stainless steel as your crucible for melting
Li, then? What sort of temperatures have you achieved with molten lithium? My experiment is going to produce over 1024 C, so this will probably be a
much more unforgiving environment. (This is for my neodymium isolation via 3Li + NdF3 == Nd + 3LiF)
From your second PDF: "Of the refractory metals, columbium, tantalum, and molybdenum are relatively stable at 1000°C". This is interesting because I
happen to have tantalum foil, so it's possible I could line my crucible with Ta to protect against attack. On the other hand, wikipedia mentions,
"[Ta] can be dissolved with hydrofluoric acid or acidic solutions containing the fluoride ion" - there will be fluoride in the mix so that may cause
problems. Any thoughts on that?
From the same source: "Various materials were subjected to a 1/16-inch-diameter stream of lithium at 590*C and 60 psig for 30 seconds. The materials
were positioned 6 feet from the orifice and were sprayed with 3.2 kg of lithium."
That sounds FUN 
|
|
|
j_sum1
Administrator
Posts: 6320
Registered: 4-10-2014
Location: At home
Member Is Offline
Mood: Most of the ducks are in a row
|
|
If you wanted to use Molybdenum, I have located a refractory boat for five dollars. http://www.tungsten.com/orphan.html
It could be good for a lithium melt.
|
|
|
The Volatile Chemist
International Hazard
Posts: 1981
Registered: 22-3-2014
Location: 'Stil' in the lab...
Member Is Offline
Mood: Copious
|
|
Is it that trust-able?
Never heard of the co. before.
|
|
|
j_sum1
Administrator
Posts: 6320
Registered: 4-10-2014
Location: At home
Member Is Offline
Mood: Most of the ducks are in a row
|
|
Well they have been round a while and update their "orphan" list every few months. Communication seemed very professional. But I guess it is a small
business operating only a few days per week. I have been waiting for email reply for a couple of days and that is unusual. We will see how my current
order goes.
There is nothing to suggest they are not legit.
|
|
|
The Volatile Chemist
International Hazard
Posts: 1981
Registered: 22-3-2014
Location: 'Stil' in the lab...
Member Is Offline
Mood: Copious
|
|
It looks cool. I mean, why not buy some tungsten foil or molybdenum disks! I would, but I have parents...Maybe later.
|
|
|
MrHomeScientist
International Hazard
Posts: 1806
Registered: 24-10-2010
Location: Flerovium
Member Is Offline
Mood: No Mood
|
|
Why not? There's nothing hazardous about tungsten and molybdenum! Unless you drop the tungsten on your foot.
|
|
|
diddi
National Hazard
Posts: 723
Registered: 23-9-2014
Location: Victoria, Australia
Member Is Offline
Mood: Fluorescent
|
|
My post on storage got lost, so here it is again. I have tried 2 methods that have been reasonably successful. firstly to sink my Li in oil, I use a
jar with straight sides and I cut a clear disk of about 3 mm plastic to fit tightly in the jar. I polished the edge of the disk and drilled a few
small holes to allow the oil to pass through. then I use it to force the Li under the oil. it is great for display as the polished disk is virtually
invisible and the Li appears to float in the middle of the jar.
Re argon gas procurement. by far the cheapest argon you will ever get is to find a mate with a MIG or TIG welder who uses 100% Ar (not the CO2/Ar mix)
and borrow a bit. the amount you use will cost about 10cents. I use welding Ar with Li and so far it has worked well. I am using this for my
investigation into REE storage as per other thread on that topic.
@mrhomescientist I bought some Li from that supplier you described. I had a foil packet with a clear packet inside. the foil was under Ar, but I
found the problem with the supplier's packaging was to do with the hot melt plastic bag sealer he uses. it has a cold spot. I looked at the seal on
the clear bag which had been heat sealed twice, but the small breach in the heat pattern allows air to slowly enter the "seal" and guess what, my
pristine Li started to tarnish overnight because I did not see the breach. I purchased another item from this supplier which arrived in very poor
condition due to inappropriate packaging. we sorted out the problem to both our satisfaction so creds where deserved.
[Edited on 1-11-2014 by diddi]
|
|
|
The Volatile Chemist
International Hazard
Posts: 1981
Registered: 22-3-2014
Location: 'Stil' in the lab...
Member Is Offline
Mood: Copious
|
|
Haha, my parents just don't like me buying things on-line, though they've gotten used to Amazon. They also wouldn't like me spending $35 (the minimum
purchase) on one or two things. They also prefer micro-chemistry to standard chemistry.
|
|
|
aga
Forum Drunkard
Posts: 7030
Registered: 25-3-2014
Member Is Offline
|
|
All Safety is an illusion.
Micro, Macro, Inbetweeno ...
Basically there is no 'safe'.
A meteorite could splatter you at Any moment, no matter what you do.
'Staying Safe' just means 'Minimising the probability of accidental death'
As Douglas Adams said: a million-to-one chance happens nine times out of ten.
|
|
|
j_sum1
Administrator
Posts: 6320
Registered: 4-10-2014
Location: At home
Member Is Offline
Mood: Most of the ducks are in a row
|
|
Took a bit of discussion to get the freight price down (USA to AUS), but today I received my shipment of tungsten plate, wires and filaments as well
as some molybdenum foil. Looks nice.
If anyone is still looking for W or Mo then I can report a positive experience.
|
|
|
gdflp
Super Moderator
Posts: 1320
Registered: 14-2-2014
Location: NY, USA
Member Is Offline
Mood: Staring at code
|
|
Just received some lithium(50g) from yaolihong2013 and it looks like I got lucky. I opened both the inner and outer packet at the same time and put
it straight under mineral oil, see below. There is some oxidation on the surface, but very little unlike MrHomeScientist's. I've only opened one of
the two 25g packets so far, I'm debating whether the second packet will last longer if I leave it in the hermetically sealed original packaging, or
put it under oil as well. Anyone have any insight they can offer?
|
|
|
elementcollector1
International Hazard
Posts: 2684
Registered: 28-12-2011
Location: The Known Universe
Member Is Offline
Mood: Molten
|
|
| Quote: Originally posted by gdflp | Just received some lithium(50g) from yaolihong2013 and it looks like I got lucky. I opened both the inner and outer packet at the same time and put
it straight under mineral oil, see below. There is some oxidation on the surface, but very little unlike MrHomeScientist's. I've only opened one of
the two 25g packets so far, I'm debating whether the second packet will last longer if I leave it in the hermetically sealed original packaging, or
put it under oil as well. Anyone have any insight they can offer?
|
I think you should put it under oil - I'm not sure how transparent the hermetically sealed packaging is, but at least under oil you'd be able to tell
how the sample was doing.
Elements Collected:52/87
Latest Acquired: Cl
Next in Line: Nd
|
|
|
| Pages:
1
2
3 |
![[*]](images/xpblue/default_icon.gif){kind=icon}
