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Author: Subject: Cesium from CsCl
Dan Vizine
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Good point. In fact, that is what I use for the distillation, a vacuum take-off adapter with a drip tip. Everywhere it touches more glass you'll lose material. That's why I went to plastic syringes instead of glass.

DON'T try to seal the ampoule connected to the apparatus while it is still hot. If you have a "blow-in" it will be very unpleasant.

Is the intention to make a single ampoule containing the entire produced amount?

But anyway, I still strongly suggest glass tubing for the ampoule. If you look at various "large" Cs ampoules from the internet (the 99.99%) kind, they use cylindrical tubing with rounded bottoms not the thinner kind with flat bottoms.

Btw, do you have any sort of inert gas available? It REALLY helps.
elementcollector1
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 Quote: DON'T try to seal the ampoule connected to the apparatus while it is still hot. If you have a "blow-in" it will be very unpleasant.

Good to know... Although knowing caesium, I would certainly wait until it cooled before doing much of anything!

 Quote: Is the intention to make a single ampoule containing the entire produced amount?

Not exactly. I have a bunch of these ampoules, and I would like to produce enough Cs to fill one of them (~1 mL). If the produced amount reaches that, I would simply stop the distillation (unless I wanted to sell to members, which now that I think of it is probably a good idea in terms of not wasting Cs compounds).

 Quote: But anyway, I still strongly suggest glass tubing for the ampoule. If you look at various "large" Cs ampoules from the internet (the 99.99%) kind, they use cylindrical tubing with rounded bottoms not the thinner kind with flat bottoms.

True, but I'm not exactly hoping for a 'large' ampoule - unless those 1mL ones count as 'large'?

 Quote: Btw, do you have any sort of inert gas available? It REALLY helps.

Unfortunately, no. I might look into procuring some when the time comes, but as of now I have no argon/nitrogen/helium.

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Dan Vizine
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Well, that's the kind of ampoule you'll need a deft touch with. The glass is thin and it will sag and constrict in an instant if you use too hot a flame with a full -1 bar vacuum (or anything close) applied to it. When I seal those types of ampoules, a "vacuum" of 50 mm Hg is way more than enough. In fact, a small rubber pipette bulb pulls plenty of vacuum to give a good seal.

If you've never done it before, I'm sure you'll practice first. If you can, it is highly desirable to melt the seal into a well-fused somewhat rounded end w/o a sharp point.

On another front, your product quality will likely depend more on your reductant than on the CsCl, which is usually 99 - 99.9 % pure, metals basis. The typical Li sample may contain a per cent of Na or more. This will co-distill with the Cs.

Ca is easier to get as a pure metal, but to get a good yield you need small clean filings to achieve homogeneity in your charge as the reaction mixture is not very fluid at all. At least you don't need too much. Do this: Ca is available as chunks on eBay. Get some, clean it with a wire wheel or brush, clamp it in a cleaned-off vice and file it while catching the filings in whatever you have around. Do this right before before use. Not the day before, but immediately before.

You could use high purity Li to best effect though. This has become (easily) commercially available to the public in the last year.

These are not new facts but they are vitally important. If you pay attention to the little things you'll get Cs that is always solid at RT.

[Edited on 26-4-2014 by Dan Vizine]
Maya
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 Quote: Well, that's the kind of ampoule you'll need a deft touch with. The glass is thin and it will sag and constrict in an instant if you use too hot a flame with a full -1 bar vacuum (or anything close) applied to it. When I seal those types of ampoules, a "vacuum" of 50 mm Hg is way more than enough. In fact, a small rubber pipette bulb pulls plenty of vacuum to give a good seal. If you've never done it before, I'm sure you'll practice first. If you can, it is highly desirable to melt the seal into a well-fused somewhat rounded end w/o a sharp point. On another front, your product quality will likely depend more on your reductant than on the CsCl, which is usually 99 - 99.9 % pure, metals basis. The typical Li sample may contain a per cent of Na or more. This will co-distill with the Cs. Ca is easier to get as a pure metal, but to get a good yield you need small clean filings to achieve homogeneity in your charge as the reaction mixture is not very fluid at all. At least you don't need too much. Do this: Ca is available as chunks on eBay. Get some, clean it with a wire wheel or brush, clamp it in a cleaned-off vice and file it while catching the filings in whatever you have around. Do this right before before use. Not the day before, but immediately before. You could use high purity Li to best effect though. This has become (easily) commercially available to the public in the last year. These are not new facts but they are vitally important. If you pay attention to the little things you'll get Cs that is always solid at RT.

Is there any particular way to get totally silver looking cesium without the yellow tinge?
Apparently even Alfa Aesear 99.98% has this yellow in it.... Yes, just a slight yellow haze. yes it is solid @ RT

I guess I could also make my own, less pure without the yellow?

Rubidium at this purity is quite silver looking

[Edited on 3-5-2014 by Maya]

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BromicAcid
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As far as I know, cesium <b>is</b> supposed to be gold in color.

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Dan Vizine
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Maya, That's a good question.

First of all, we need to define what they're talking when they say 99.9 or 9.999% purity. As I'm sure you know, there are two ways manufacturers advertize purities. One is an overall purity and the other is "Metals Basis". I've seen ampoules marked 99.999% purity that were golden, suggesting that's a metals basis value. The color likely comes from oxygen and that's not part of their assay.

On the other hand, my cesium is clearly less pure than that on a metals basis but for the the first few moments of its existence it is silver or close to it. It inevitably turns golden because of equipment limitations (meaning some oxygen leakage). I think it may be quite difficult to prepare it and preserve it as a silver metal. Even the various authorities who publish data on Cs don't have a consistent view. Some say it's silver, some say it's golden tinted. What I take away from that is that some samples had less O2 than others and that silver or close to it is likely the true color. I'd like to see what it looks like after a few distillations and before much time elapses.

I can tell you that I know for sure that the yellow color increases with O2 content. It actually goes through a pallet of deepening colors leading to black, the color of the highest oxide.

I guess my suggestion would be to try several redistillations in thoroughly baked glassware at the best vacuums you can attain with subsequent sealing under vacuum. I seem to have the recollection that you just may have access to high quality lab facilities? Even then, I don't think silver is automatically guaranteed.

[Edited on 3-5-2014 by Dan Vizine]
Maya
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Those were my initial thoughts as well. Metals basis 99.98% initially with subsequent yellowing thru equipment imperfections. It is pretty tho' , even more impressive than Hg b/c of the phase changes.

 Quote: I guess my suggestion would be to try several redistillations in thoroughly baked glassware at the best vacuums you can attain with subsequent sealing under vacuum. I seem to have the recollection that you just may have access to high quality lab facilities? Even then, I don't think silver is automatically guaranteed.

you flatter me , yes I actually do have the equipment, but it would take alot to set up space wise and time wise right now. easier just to acquire it outright. maybe when I have more time I'll go for shiny by actually making a sample myself. That always gives you a nice warm fuzzy feeling!

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Fleaker
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The pure metal is silver and does not wet glass. Any oxygen and it will begin to shift more and more golden. In any event, it's its own getter so if it is distilled under a diffusion pump vacuum, your metal will be very clean.

There are some issues in determining purity of a Cs/Rb samples--if it is made into its hydroxide and handled in glass, it may leach out some Na/K. I suppose it may be better to carefully dissolve it in chilled t-butyl alcohol and then off to ICP with it.

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Zyklon-A
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 Quote: Originally posted by Zan Divine You should strive for 0.001 mm Hg for the best results.

Can someone direct me to a suitable 0.001 torr vacuum?
I'm not sure what's wrong, but I haven't found anything even close:http://www.ebay.com/sch/i.html?_trksid=p2050601.m570.l1313.T...

Burner
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Quote: Originally posted by Zyklonb
 Quote: Originally posted by Zan Divine You should strive for 0.001 mm Hg for the best results.

Can someone direct me to a suitable 0.001 torr vacuum?
I'm not sure what's wrong, but I haven't found anything even close:http://www.ebay.com/sch/i.html?_trksid=p2050601.m570.l1313.T...

Look at things such as the Welch DirecTorr (and similar) vacuum pumps (http://www.daigger.com/store/welch-directorr-vacuum-pumps209...). There are all capable of that level or performance.

Other possibilities would include multi-stage vacuum pumps such as the Welch DuoSeal (and similar) that can achieve 0.001 torr (http://www.chemglass.com/pages/pdf/manuals/AF-0350_WelchVacu...).

[Edited on 9-5-2014 by Burner]
HeYBrO
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https://www.youtube.com/watch?v=W5B5mj6-fqk Zan! i think you should enter! great opportunity to get a free diffusion pump!

Dan Vizine
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Thanks, HeBrO, but nothing that I do rises to a competitive level because none of it is new. This will deservedly go to someone working to extend something once considered to be a lab process into the realm of the home lab. My projects are somewhat less altruistic, they always have a commercial aspect designed to finance the next big project.
Zyklon-A
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I'm looking for some sealant tape that can survive gaseous Cs.
I found something that looks promising, it's compatible at temps up to 635°C, is based on reducing agents, (and thus wont oxidize the Cs, maybe). It says it's made of "nuclear grade graphite and a nuclear quality petroleum-based carrier", whatever that means.
Here's the link:http://www.newmantools.com/chemicals/neo1260.htm, I'm looking at the first one in the list.
Does this look like it will work?
Alternatively I could weld all of the joints together, but I would like to have at least one (joint) so I could separate the heating chamber from the condenser if I want.
[EDIT] Also, I'll be using Ca to reduce the CsCl not Li, so the temperature will have to be a little higher.

[Edited on 15-12-2014 by Zyklon-A]

careysub
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 Quote: Originally posted by Zyklon-A ...It says it's made of "nuclear grade graphite and a nuclear quality petroleum-based carrier", whatever that means. ...

It means "no boron" (down to the low single digit ppm level).
Zyklon-A
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I see, thanks. Any idea if it'll work for the aplication though?
careysub
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 Quote: Originally posted by Zyklon-A I see, thanks. Any idea if it'll work for the aplication though?

According to this graphite is completely resistant to molten potassium:

The petroleum carrier, I am less sure about. Alkali metals don't react with paraffinic hydrocarbons under ordinary conditions. But if you heat it enough to drive off the carrier, that won't be an issue in any case.
Zyklon-A
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Thanks for the information, but I went ahead and welded all the joints. That sealant linked above cost $60 for the smallest quantity available, I can build an entire new apparatus for less than$20, so no thanks...

elementcollector1
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So I went and tracked down all the legal info on shipping caesium metal through FedEx, and here's what I found:

49 CFR 173.13 - Exceptions for Class 3, Divisions 4.1, 4.2, 4.3, 5.1, 6.1, and Classes 8 and 9 materials:

(2) For solids:

(i) The hazardous material must be placed in a tightly closed glass, plastic or metal inner packaging. The net quantity of material in any inner packaging may not exceed 2.85kg (6.25 pounds). For transportation by aircraft, the net quantity in one package may not exceed the quantity specified in columns (9A) or (9B), as appropriate.

(ii) The inner packaging must be placed in a hermetically sealed barrier bag which is impervious to the lading.

(iii) The barrier bag and its contents must be placed in a fiberboard box that is placed in a hermetically-sealed barrier bag which is impervious to the lading.

(iv) The intermediate packaging must be placed inside an outer packaging conforming to § 173.211.

(v) Not more than four intermediate packagings are permitted in an outer packaging.

§ 173.211 Non-bulk packagings for solid hazardous materials in Packing Group I:

(b) The following combination packagings are authorized:

Outer packagings:
Steel drum: 1A1 or 1A2
Aluminum drum: 1B1 or 1B2
Metal drum other than steel or aluminum: 1N1 or 1N2
Plywood drum: 1D
Fiber drum: 1G
Plastic drum: 1H1 or 1H2
Wooden barrel: 2C2
Steel jerrican: 3A1 or 3A2
Plastic jerrican: 3H1 or 3H2
Aluminum jerrican: 3B1 or 3B2
Steel box: 4A
Aluminum box: 4B
Natural wood box: 4C1 or 4C2
Plywood box: 4D
Reconstituted wood box: 4F
Fiberboard box: 4G
Solid plastic box: 4H2
Metal box other than steel or aluminum: 4N
Inner packagings:
Glass or earthenware receptacles
Plastic receptacles
Metal receptacles
Glass ampoules <- How is this an 'outer packaging'?

(c) Except for transportation by passenger aircraft, the following single packagings are authorized:

Steel drum: 1A1 or 1A2
Aluminum drum: 1B1 or 1B2
Metal drum other than steel or aluminum: 1N1 or 1N2
Plastic drum: 1H1 or 1H2
Fiber drum: 1G
Steel jerrican: 3A1 or 3A2
Plastic jerrican: 3H1 or 3H2
Aluminum jerrican: 3B1 or 3B2
Steel box with liner: 4A
Aluminum box with liner: 4B
Metal box other than steel or aluminum: 4N
Natural wood box, sift proof: 4C2
Plastic receptacle in steel, aluminum, plywood, fiber or plastic drum: 6HA1, 6HB1, 6HD1, 6HG1 or 6HH1
Glass, porcelain or stoneware in steel, aluminum, plywood or fiber drum: 6PA1, 6PB1, 6PD1 or 6PG1
Glass, porcelain or stoneware in steel, aluminum, wooden or fiberboard box: 6PA2, 6PB2, 6PC or 6PG2
Glass, porcelain or stoneware in expanded or solid plastic packaging: 6PH1 or 6PH2
Cylinders, as prescribed for any compressed gas, except for Specification 8 and 3HT

If I'm reading this right, the "correct" manner of transport would be to place a 1 mL ampoule inside a hermetically sealed bag, which is then placed inside a fiberboard box (is that another word for cardboard, or a different substance entirely?), which is then placed inside another hermetically sealed bag, which is then placed in another fiberboard box. Is this right? If so, that doesn't seem that bad. Though it does mention that the bags must be immune to the 'lading', which according to Google is the caesium itself. Not sure what plastics, if any, are immune to caesium - my Google-fu is ridiculously weak tonight.

Sources:
https://www.law.cornell.edu/cfr/text/49/173.13
https://www.law.cornell.edu/cfr/text/49/173.211

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Next in Line: Nd
Fleaker
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You can ship less than 1000 g of it. It is forbidden to go via air.

When I have had alkali metals like Cs and Rb shipped, they come in ampoules, bagged, put into a can w/ vermiculite, can sealed and put in a fiber box of the appropriate crush strength.