Sciencemadness Discussion Board

Cesium from CsCl

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h0lx - 4-11-2006 at 07:06

I could swear in my mothers name, I posted it before, but the thread vanished? Or was it deleted? Please inform me by U2U if you are going to delete this, so I won't post the third time.

I am about to obtain 100g of Cesium Chloride and I am willing to melt and electrolyse it. But I need some kind of tips or proceedures, I don't have the possibility to experiment much, because the salt is really expensive. I was thinking about some bell type thing at the cathode, with either vacuum or inert atmosphere. All tips/ideas/proceedures/drawings/picture/anything on the subject appreciated.

chromium - 4-11-2006 at 07:20

Try it at first with NaCl or NaOH, and only after you can succesfully extract sodium, you may consider extracting cesium as it is much harder to do.

[Edited on 4-11-2006 by chromium]

[Edited on 4-11-2006 by chromium]

The_Davster - 4-11-2006 at 09:35

CsCl melts at 646 C, Cs metal boils at 669C. Without propper temp control you are going to boil away the cesium.

If I was in the market for making cesium, I would go the way industry does it, distill a cesium salt with sodium.

I don't need to tell you that your inert atmosphere must be perfect, cesium catches fire in air readily.

neutrino - 4-11-2006 at 13:18

I am reminded of US4725311. The relevant part is quoted below.

Quote:
EXAMPLE 5

Production of Cesium Metal From Cesium Hydroxide

In the procedure described in FIG. 1, a mixture of 32.5 g cesium hydroxide (217 millimoles), 5.4 g magnesium chips (220 millimoles) and 300 ml undecane are heated with stirring at the boiling temperature of 196.degree. C. in the procedure of Example 1. 1.6 g (22 millimoles) tertiary butanol dissolved in undecane are then added in drops during 25 min and the contents of the reactor is heated with refluxing for additional 13 hours (H.sub.2 O evolution: 22 millimoles). After cooling to temperatures below the melting point of cesium, the reaction product mixture is poured onto a fine-mesh sieve to separate cesium regulus having a silvery luster from the magnesia. When the molten cesium has been filtered through a frit, the pure metal is obtained in a yield of 11.2 g, corresponding to 39% of theory.

EXAMPLE 6

Production of Cesium Metal From Cesium Alkoxide

In a reactor as described in Example 1, 69.6 g cesium hydroxide (443 millimoles CsOH, 176 millimoles H.sub.2 O) and 18.0 g (741 millimoles) magnesium chips in 300 ml dodecane are heated. with stirring at the boiling temperature (216.degree. C.) for 1.5 hours. The H.sub.2 evolution resulting from the dehydration amounted to 180 millimoles.

Thereafter, a mixture of 33.0 g (445 millimoles) tertiary butanol and 50 ml dodecane is added in drops within 2 hours and the mixture is then maintained at the boiling temperature for an additional hour. This resulted in an evolution of 440 millimoles H.sub.2 owing to the formation of cesium tertiary butylate.

The reaction product mixture consisted of a grey suspension and contained cesium spheres, which has a silvery luster and had been formed by the reaction of the cesium tertiary butylate with the surplus magnesium metal (122 millimoles). When the reaction product mixture had cooled to about 20.degree. C. it was filtered through a sieve to separate the cesium metal. Yield: 11.7 g (88 millimoles)=36% of theoretical yield. The filtrate that had passed through the sieve was filtered through a frit. The residue retained on the frit was washed several times with tetrahydrofurane.

From the frit filtrate containing 276 millimoles cesium butylate and 84 millimoles magnesium butylate, pure cesium butylate could be recovered by recrystallization from a mixture of tetrahydrofurane and toluene.


If you're interested, look at the Unconventional Sodium thread. There was some discussion about this patent there.

Fleaker - 4-11-2006 at 13:59

Alternatively, you can use the method in Brauer which is (for me) the best available. CsCl is heated with calcium powder or turnings under high vacuum in a thrice purged system that must be constructed of either stainless steel or a temperature resistant glass. This is the method I will use when/if I get around to doing it. I happen to have a friend who is supplying the cesium chloride. If you'd like, feel free to U2U me about it. The yield is 98% of theory. I should remind you that electrolyzing it is not easy since the metal is soluble in its salt. You could however electrolyze the molten salt above the B.P. of Cs and distill over cesium, but you still will have CsCl in the metal: the salt is volatile, especially in vacuum. Also, reducing with sodium has inherent problems as well if conducted in vacuo: some sodium inevitably distills over as well.


Brauer's is availabe in the library.

h0lx - 5-11-2006 at 02:40

How can Ca replace Cs? It is much less active than Cs.

woelen - 5-11-2006 at 05:33

Cs is more volatile. An equilibrium will exist between Ca and Cs. However, Cs can be driven off as gas, and Ca remains behind. This causes the equilibrium to be driven to the Cs side:

2Cs(+) + Ca <-->>>>> 2Cs + Ca(2+)

not_important - 5-11-2006 at 06:52

I have read, but after a search can not locate the reference, of the production of caesium metal from the reaction of CsF with an excess of iron powder in a stainless steel retort under reduced pressure (and after argon flush, before pumpdown)

2 CsF + Fe => FeF2 + 2 Cs (gas)

FeF2 has a fairly high boiling point, something like 1800 C, CsF is 1250 C or so and melts a little above the boiling point of Cs at 1 atmosphere Again this is a case of forcing the reaction through removal of a product.

Maya - 5-11-2006 at 22:34

I'm wondering if you could do the cesium or rubidium separation/distillation in an a quartz apparatus instead of borosilicate since I hear that lithium will attack and consume borosilicate at high temps. do the other alkali metals react with borosilicate as well so that you can't use it for distillation ? would quartz work or be similarly affected?

[Edited on 6-11-2006 by Maya]

garage chemist - 6-11-2006 at 00:10

There is also a method of heating cesium dichromate with zirconium powder in vacuum that is stated to be the most convenient means of cesium production, as the temperature only needs to be at the boiling point of Cs and not much higher (no equilibrium has to be shifted). I think this is also outlined in Brauer, look it up.

woelen - 6-11-2006 at 06:50

And where could one obtain Cs2Cr2O7? The only dichromates, which are available for the home chemist (and even those with some difficulty in many countries) are the sodium, potassium and ammonium salts.

Or is there a nice synth of cesium dichromate from the other dichromates. Is Cs2Cr2O7 less soluble, so that it can be crystallized? This subject is interesting to me, because I hope to receive 100 grams of CsBr next week or so.

[Edited on 6-11-06 by woelen]

garage chemist - 6-11-2006 at 07:00

As potassium dichromate is significantly less soluble that sodium dichromate, I would expect the cesium salt to follow the rule and be even less soluble (with perchlorates it follows this trend, KClO4, RbClO4 and CsClO4 are progressively less soluble).
I have no reliable data however.

[Edited on 6-11-2006 by garage chemist]

chromium - 6-11-2006 at 07:34

It may be that garage chemists idea does not work as cesium chromate is quite well soluble in water. Do not know about dichromate though.

Some cesium salts can be made by reacting cesium sulfate with barium salt of desired anion. Cesium hydroxide can also be made this way.

Cesium sulfate can probably be prepared by heating cesium halide with sulfuric acid and lettting volatile acid to escape but it may be quite hard to go beyond hydrosulfate this way.

Fleaker - 6-11-2006 at 16:15

Woelen, look in Brauer's, there is a section on the formation of rubidium and cesium (di)chromates. The method chromium mentioned is what is actually used. Barium dichromate is added to a warm solution of Cs2SO4 (or that of rubidium).

Waffles - 6-11-2006 at 16:55

Quote:
Originally posted by Maya
I'm wondering if you could do the cesium or rubidium separation/distillation in an a quartz apparatus instead of borosilicate since I hear that lithium will attack and consume borosilicate at high temps. do the other alkali metals react with borosilicate as well so that you can't use it for distillation ? would quartz work or be similarly affected?

[Edited on 6-11-2006 by Maya]


Yes. There is plenty of literature on the distillation of K/Na/Rb/Cs in borosilicate/quartz.
Lithium is fairly unique in that respect. No worries in that respect.

Does anyone want to explain to me why CESIUM is so much cheaper than RUBIDIUM? Is it just because of the relative abundances?

(Edited so it actually makes sense)

[Edited on 8-11-2006 by iamthewaffler]

Maya - 8-11-2006 at 00:18

Quote:

Does anyone want to explain to me why rubidium is so much cheaper than cesium? Is it just because of the relative abundances?



Seems around here the opposite, cesium is much cheaper then rubidium

Waffles - 8-11-2006 at 00:25

Quote:
Originally posted by Maya
Quote:

Does anyone want to explain to me why rubidium is so much cheaper than cesium? Is it just because of the relative abundances?



Seems around here the opposite, cesium is much cheaper then rubidium


Um. That's what I meant. I feeeeeel dumb.

Pok - 24-12-2010 at 18:38

Quote: Originally posted by iamthewaffler  

why CESIUM is so much cheaper than RUBIDIUM? Is it just because of the relative abundances?
Only cesium has own minerals with high Cs content and therefore easily winnable Cs (e.g. Pollucite (Cs-Na-Silicate), Pautovite (Cs-Fe-Sulphide), Cesstibtantite (Cs-Na-Sb-Ta-Oxide)), rubidium is only present in other minerals (small % concentrations in Leucite, Lepidolite, others) and has no known own mineral (can only be produced as a side product). - This is often the case for production of elements: concentration in a mineral is more important than total concentration in earth crust. (e.g. gallium is as abundant in the earth crust as lead, but many times more expensive, because lead forms many minerals = high local concentration = easily winnable....gallium forms very rare minerals, is mostly present in a scattered pattern))

So: relative abundances are not the reason: wikipedia.de says: Cs = 6.5 ppm, Rb = 29 ppm (if these values aren't correct: other sources at least say: "Rb > Cs"

Another reason might be: Cs is used in a larger amount (and thus produced) in science and technology than Rb. Probably because chem/phys. Cs-K difference is larger than Rb/K (???).

Cuauhtemoc - 25-12-2010 at 00:26

Hm, after the sucess with "pok's" method for Potassium, maybe you guys should try with NaOH and then with CsOH, as according to the same patent it should work.
That will be a pretty big breakthrough in amateur science.

blogfast25 - 25-12-2010 at 06:43

Quote: Originally posted by Cuauhtemoc  
Hm, after the sucess with "pok's" method for Potassium, maybe you guys should try with NaOH and then with CsOH, as according to the same patent it should work.
That will be a pretty big breakthrough in amateur science.


Yes but we need first to tackle the supposedly easier sodium with the alkoxyde - Mg reduction method. So far no one here has even attempted, presumably because the patented reaction times are so high. Issues with the solubility of sodium t-butoxyde, we feel...

Arthur Dent - 25-12-2010 at 06:52

Quote: Originally posted by Cuauhtemoc  
Hm, after the sucess with "pok's" method for Potassium, maybe you guys should try with NaOH and then with CsOH, as according to the same patent it should work.
That will be a pretty big breakthrough in amateur science.


Indeed, however Cs is such a scary, reactive metal, that it would have to be done in a professional laboratory under the most ideal of conditions, in a noble gas atmosphere, with the most precise of temperature controls and the highest purity of anhydrous reagents. As tempting as it would be, I would never try this in a "home lab"... too dangerous.

There are elements or chemicals that I don't mind doing without, simply because they are above my level of comfort. Cesium and Rubidium are some of them.

Robert

blogfast25 - 25-12-2010 at 09:24

Quote: Originally posted by Arthur Dent  

There are elements or chemicals that I don't mind doing without, simply because they are above my level of comfort. Cesium and Rubidium are some of them.

Robert


I take it you're OK with fluorine then! :P

Arthur Dent - 25-12-2010 at 12:15

Yup!
I have two or three cups of chlorine trifluoride every morning, makes my stomach a bit upset though. ;)

Yeah, I have to admit I never take any chemicals for granted, and before I proceed with an experiment, study its mechanisms and interactions thoroughly. There are many chemicals that I deem too reactive, noxious or plain dangerous for me to have, like elemental phosphorus, cyanide compounds, volatile toxic stuff and so on. I have limited space and I can't have a cool lab with a fume hood so I do my "smelly" stuff outdoors! LOL

Plus many chemicals would serve no purpose for my basic chemistry usage, mainly electroplating, etching, precious metal recuperation and geeky, fun experiments.

Robert


Robert

[Edited on 25-12-2010 by Arthur Dent]

Fleaker - 25-12-2010 at 14:20

In my experience, K/Na alloy is worse than elemental cesium because it is spontaneously flammable with air and can generate much more hydrogen gram for gram than cesium can. Cs and Rb might react "quicker" but they're stoichiometrically less dangerous with water. Both can be handled in a glove box (or a bag filled with Ar). Treat it with respect as you would any pyrophoric material and you'll be fine.

While KOH may not etch glass at that temperature, I'm willing to bet that CsOH will. CsOH is much more corrosive than KOH.

The WiZard is In - 25-12-2010 at 18:00

Quote: Originally posted by h0lx  
I am about to obtain 100g of Cesium Chloride and I am willing to melt and electrolyse it. But I need some kind of tips or proceedures, I don't have the possibility to experiment much, because the salt is really expensive. I was thinking about some bell type thing at the cathode, with either vacuum or inert atmosphere. All tips/ideas/proceedures/drawings/picture/anything on the subject appreciated.


Tip? Sure answers to you question can be found in —

Mellor's Comprehensive Treatise on Inorganic and Theoretical
Chemistry Volume II Supplement III p. 2287 & ff.

75% yield by heating the chloride w/ calcium carbide in vacuo
@ 700-800o seems the easiest. However, you may find one of
the other methods better suited to your I got's.

The barium azide method seems upon me — the most exciting...!


Say - Whatever happened to the a in cerium?
i In aluminum? a in archeology?


Zan Divine - 3-12-2011 at 21:21

Just made Cesium


Well, it was too damn easy.
Used patent US3164461.
This is a Li metallothermic redn. in vacuo @ 585 degrees C.
Yield is nearly quantitative in about a total 15 min of reaction time (at temp).
CsCl electrolysis - such a bad idea no comment necessary
CsOH + Mg - Just wait until you price CsOH.....Work up sucks
CsCl + CaC2 - lower yield, higher temp
Cs azide - Hah! Just try to get barium azide
I spent hours thinking about this before jumping in. CsCl + Li (or Ca) is the only way worth considering. Esp. if, like me, you copped 250 g of CsCl for $50 on e-bay.
Rubidium next...maybe. RbCl is $350/50g from only source I've found. Yeah, That'll be the friggin' day.....
Ahhhh....how about this?....Got a Rubidium halide? Want Rb metal? I'll do it for 50%.

PS What is that "harmless" doing under my name? You apparently don't know me......
PPS Yeah, I KNOW the pics suck. If you want to see full size ones I think this will do it:

http://i43.tinypic.com/drcl5l.jpg[/IMG]

http://i43.tinypic.com/20fpzsw.jpg[/IMG]

One of the harder things about making Cs was wading through the information/disinformation. Most notably: Cesium is pyrophoric. No, it isn't. At least not at 70 degrees F and 66% relative humidity. When I opened the reactor, I expected fire. The only fire I saw was when I touched molten Cs with a leather welding glove. Amusing.



The Process sm.jpg - 108kB The Setup sm.jpg - 88kB







[Edited on 4-12-2011 by Zan Divine]

blogfast25 - 4-12-2011 at 07:05

Interesting! Reduction of CsCl with Li and removal of Cs by vacuum distillation, if I understand well? Could you provide some more details, please? And more photos of the metal too, does it have that slightly golden shimmer that is claimed?

Is that a hair drier on the left photo?

('harmless' is an attribute any new member here gets. Not to be taken seriously)



[Edited on 4-12-2011 by blogfast25]

Zan Divine - 4-12-2011 at 08:09



This is a screenshot of the US patent. With % yields like those, and especially with the high purities reported, it's hard not to sigh and wish they hadn't made it so easy. I'd love to claim that my Cs was the end result of painstaking trials eventually culminating in sucess, but the truth is that I just followed the instructions.

This 12.5 g rxn. (of the cesium salt) was a quick and dirty scouting run whose main purpose was to get experience in handling Cs and to investigate if the physical construction of my apparatus was suitable.

Among my main questions was this one: Given that Cs vapor leaves the reactor near 600 degrees C, would I need to cool the exit pipe with water? ...or...maybe I'd need to heat it if the Cs froze in it? It was the latter, and that's the reason for the home-built high temp heat gun. Cs tended to freeze in the narrow downwards tube in the center of the vacuum take-off adapter as well as in the last few inches of the 12" long 1/4" stainless steel pipe. Gentle warming solved this problem.

My reactor is a stainless steel tube unto which I welded a standard ferrous pipe fitting (I really don't see why SS is mandated. Steel is suitable, as is monel.) allowing me to attach/detach the condenser pipe for charging/cleaning.

This is actually something I made for my phosphorus project. I'm going to make samples of all of the hard to get, "big-game" elements and offer them on e-bay to other collectors who shouldn't have to pay $100 - $140 per gram for Cs or Rb and those who should be able to buy a small sample of white P without selling their first-born. Bromine was first, cesium is in progress, rubidium will be next and then possibly white P. I need to see how dickish the DEA is about gram quantities. We all know that I2 and P are watched because of their methadrine connection, yet I see dozens of iodine samples for sale and a few (only red) P samples and as long as they are small, seem to elicit no hysterical overreactions.

I'll post pics today or tomorrow of my production scale apparatus which uses part of a SS "lecture bottle" (for gasses) as the reactor and an old heating element from an oven to provide a nice, sheathed source of heat.

The crude metal was submerged in mineral oil and it's hard to see it because the high index of refraction of the oil distorts the image in the small flask. In the future the receiver will be sized so that it is full at the end of the reaction. Now that the prelim. results are in and it's thumbs up, I'm going to rent an inert gas cylinder (big deposit, heavy pain in the ass) or see if heating (NH4)2Cr2O7 gives me a usuable grade and amount of N2. I'm going to eventually use a glove-bag & inert atmosphere to package samples.






[Edited on 4-12-2011 by Zan Divine]

blogfast25 - 4-12-2011 at 08:35

Thanks, Zan!

Considering how peacock proud several of us were for making gram amounts of potassium metal with a procedure that’s quite unique and interesting but takes about 3 hours to complete, this is a remarkably quick and easy way of doing things and obtaining the ‘emperor of metals’!

For heating the ‘condenser tube’ you might consider the sort of heater coil amateur astronomers use to prevent their telescopes from frosting over on a cold night. Or a ‘heater ribbon’ home brewers use to keep their fermentation buckets in the right temperature range. Both are very low power heaters that should allow to keep the condenser just above 30 C. Very 'off the shelf'.

As regards selling the stuff, good luck with that: the market can’t be very large but competitively priced you might sell quite a bit of it…

I'm betting this thread will go 'sticky' in no time...

The patent in question.



[Edited on 4-12-2011 by blogfast25]

Zan Divine - 4-12-2011 at 10:35

I'm aware of the method. It was actually the method I was going to use before I remembered that I had a monel 24/40 joint which allowed a vacuum-tight metal-to-glass transition. [ In reterospect, this is actually overkill as, by the time cesium reaches this area, it's only barely warm and, as long as the central SS tube extends past the seal area, won't touch the seal anyway.]

I also was deterred by the high cost of CsOH. I had a quote of $520/100g + shipping of ~$100 (wtf is THAT about?).

To anybody considering the quest for the heavier group 1 elements I can't emphasize how limited you are without a good vacuum pump. When I recently bought my used pump on e-bay there were 2 other similar pumps I was considering, one even with a money-back guarantee, that I was sure would have worked. The prices were from $ 80 to $100 delivered. These are lab quality single-stage oil-filled pumps capable of 0.01 mm Hg or better. Buying tips: look for units that look like they were plumbed in vs. having hose connections. Those encounter less abuse. If a unit is sold untested look at the pic. Is the cord missing? It was probably hard-wired in & working when salvaged and the seller just didn't want to take the time to attach a power cord to test it. Vacuum pumps that have lots of splashes and stains are probably ugly inside as well. Avoid them on average. I think anyone can have a nice vacuum pump for $100 or less and you'll be pleased at the number of avenues that open up when you do.

Anyway, back to the chemistry at hand...as long as the produced metal can be volatilized much easier than can Li (BPs...671 for Cs, 688 for Rb, 759 for K, 883 for Na all versus 1342 for Li) the reaction will suceed to a greater or lesser extent. With Le Chatelier's principle in charge of the kitchen, electronegativities are irrelevant.

It may surprise some to know that carbon has been used to reduce Cs compounds to the metal. As long as CO escapes the equilibrium is pushed to give Cs metal.

And finally, I'd like to say kudos to those who succeeded in making K. I'm not yet familiar with this site and its members and achievements but I have caught on to the fact that many are self-taught or have some training and do this out of pure love of chemistry and this is inspiring.

As for me, I spent ~26 straight years doing synthesis all day long on continually changing projects plus 4 years of vacuum-line / glovebox research in undergrad. and grad. school. Backed by a very well equipped shop, an 8x10' room filled with SS, aluminium, teflon, graphite,etc ....ad infinitum, and no current outlet for my chemistry proclivities (current job is more like engineering) I troll the internet for fun things to make. I've never yet set my sights on any target except purified tantalum that I didn't achieve. Some things just require too much financial outlay.

And lastly, my primary hope with many of these samples is to trade for elements I don't have yet. These include Re and Th especially, also Os, Ir, Hf and U and the lanthanides prominently and then As, Tl, Sr, Se and a handful of others.

It's a funny thing about markets. "Sexy" elements like group 1, Br, Ga and a few others move well. I'll be offering K next week. I had beautiful Ta samples priced at 1/2 of the competition and they took weeks! Go figure.

I don't yet know about this "sticky" of which you speak.....






[Edited on 4-12-2011 by Zan Divine]

blogfast25 - 4-12-2011 at 10:55

CsOH is hellishly expensive. Hard to make and doesn’t have all that much use, I’m guessing.

There’s no real reason why you can’t use (vacuum proof) glass all the way, except for the reactor itself, right?

What pressure did you operate at? My experience with vacuum is really limited, so that would be a learning curve with some much needed dry runs.

Tantalum? What did you try? I’m guessing reduction of Ta2O5 with Mg, boosted with strong preheating, could achieve the MP of Ta.

Zan Divine - 4-12-2011 at 11:43

That's an interesting point you raise. The reaction may proceed fastest at around 600 or above but below the softening point of Pyrex ( I think I remember a figure of about 550 as the service ceiling...don't quote me on that) the reaction doubtlessly proceeds. A small metal cup with reactants contained within a glass apparatus was actually mentioned in the literature...somewhere. Sorry I can offer no further details, it's something I read but didn't save.

My pump is a Hitachi 160VP Cutevac rated at a pumping speed of 174 L/min and an ultimate vac. of 0.01 Pa. Pumping speed is kind of unimportant with a small aparatus. This is WAY more than needed. The vacuum converts to 7.5 x 10 to the -2 mmHg.

New reactor:http://tinypic.com/r/izrme0/5

Pump:

The Ta was made via Na + K2TaF7 in a steel bomb evacuated by an aspirator and welded shut. I believe the reaction proceeded ok but the rxn. produces a powder.
Never having an inert gas meant every attempt at consolidation by heating a pressed compact failed. It just wasn't worth getting the gas for. It was a half-failure perhaps.


[Edited on 4-12-2011 by Zan Divine]

blogfast25 - 4-12-2011 at 12:54

I wasn’t really thinking of a glass reactor, just glass for anything downstream from it: that would save on one glass/metal joint.

So 0.075 mm Hg, on average slightly above values reported in the patent (I’m surprised this could be patented at all: there’s really nothing particularly new about the idea).

K2TaF6 reduced with sodium will give you powder, of course.

PS: you’ve just committed your first cardinal sin ;) here: an oversized photo!



[Edited on 4-12-2011 by blogfast25]

Zan Divine - 4-12-2011 at 16:40



These are a couple ampoules I made up by melting the Cs under mineral oil and pipetting in air into open amps.
The tips of the pipettes smoked during transfer. Evacuated amps. and sealed under a vacuum. This is nothing more than a crude first attempt. Quality will improve with Argon.

The pipettes are on my patio being exposed to air/moisture slowly. If you throw them into water they will likely break. Reaction with H2O is SO VERY VIOLENT. Do not EVER warm or cool glass containing Cs with a water bath. I just can't stress enough how much worse the reaction with water is than K and water. I use cold sand for cooling and warm air for heating. When Cs burns in air it's not very different from K..... but the reaction with water...!!!!

[Edited on 5-12-2011 by Zan Divine]

blogfast25 - 5-12-2011 at 07:19

This is the only video I know of that shows the reaction with water of Li, Na, K, Rb and Cs in comparable conditions. Cs is the only one that manages to shatter the glass container. This one excels in clarity. Water and cesium really don’t mix. And this one’s Cesium porn but no water. (But I’m sure you’ve watched all of these before)

I’m getting concerned for my fellow forum members: someone displays ampoules of home made Cs metal and they don’t lign up to come and see them?!? Wakey, wakey, chaps! Something interesting's hapening here!

plastics - 5-12-2011 at 09:05

Interesting

Our very own len1 synthesised cesium by heating CsCl with calcium under vacuum at 640 - 700 C. This was described in his book "small-scale synthesis of laboratory reagents"

Cesium.jpg - 87kB

MrHomeScientist - 5-12-2011 at 10:51

Extremely interesting synthesis, congratulations! Seems a lot easier than I would expect for something like cesium.

In that last picture of the two ampoules, are they both cesium? The one on the left looks very distinctly silver instead of gold. It looks a lot more like one of the other alkali metals than cesium.

Zan Divine - 5-12-2011 at 11:08

Calcium was my second choice. Due to lithium's higher % yield and the fact that it would be liquid at the rxn. temp and Ca wouldn't, I chose it for the reductant. The Cs in this run was made using the Li from 2 size AA lithium batteries. This lithium is not exactly the cleanest available but it worked well enough.

Blogfast, thanks for the links. I had only seen the first one previously. I apologize for looking past your earlier question of amount. I had no intention of quantifying this run. In my estimation it must have been 6-7+ grams in the flask and another half a gram or so hung up in the glassware. When I get the argon cylinder more quantitative results will follow.

MrHomeScientist, Thank you and they are both cesium. The stuff degrades before your very eyes though. Even the dissolved oxygen in mineral oil quickly attacks it. Don't read too much into the color. Cs is silver just like the others. Trace oxygen contamination causes a golden hue to be displayed. The golden color is just part of the element's mystique. People want to believe it's intrinsic, but it really isn't.

I have no doubt at this point that making Cs is the easy part. Effective packaging of clean material will be harder.

[Edited on 5-12-2011 by Zan Divine]

blogfast25 - 5-12-2011 at 13:00

Quote: Originally posted by Zan Divine  

I have no doubt at this point that making Cs is the easy part. Effective packaging of clean material will be harder.

[Edited on 5-12-2011 by Zan Divine]


Yep. Packing in completely inert atmosphere seems to be the only possibility I think. Start thinking 'airtight positive argon pressure glove box'! I can't see how it can be done safely and without sample corrosion otherwise. It's something that will increase the cost very considerably.

[Edited on 5-12-2011 by blogfast25]

Zan Divine - 5-12-2011 at 15:12

Interestingly, I'm in charge of installation & servicing for our company in the US....our product? Gloveboxes.

Just bought an S cylinder of argon. Let's see how well a good quality glovebag works.

Strategy for next prep:
1) Rigorously clean inside of apparatus.
2) Obtain clean Li (in progress)
3) Size reaction and receiver so that the small round-bottom is full at the end.
4) Separate product flask, purge head space with argon.Stopper.
5) Into the glovebag. Cs withdrawn from below surface of sample and loaded into ampoule....etc.

I think I'll do the next reaction with the aim of producing about 18 grams which will fill a 10 mL 14/20 rb.

I'll keep you posted. Meanwhile business travel will eat up a number of upcoming days so it won't be real soon.

blogfast25 - 6-12-2011 at 08:46

Remember that your bunsen or propane torch won't be of any use inside an argon filled glovebag or glove box, Just one more of these nagging problems :(

Zan Divine - 6-12-2011 at 09:23

What I use as a sealing technique is to put a compressed pipette bulb over the end of the ampoule. As it tries to expand it pulls just the right negative pressure on the ampoule to allow easy sealing. I'm sure I can bring them out and seal them cleanly at that point.

Zan Divine - 15-12-2011 at 21:25

This may be new to the foum...

Attachment: Rb & Cs from the chlorides.pdf (1MB)
This file has been downloaded 1121 times


blogfast25 - 17-12-2011 at 06:15

Well, there you go: the answer to all your packing problems without a glovebox! ;)

Zan Divine - 21-12-2011 at 20:49

This is a shot of the metal from my first production run. Pre-drying of the reactor, flame drying of the glassware and argon for the necessary blanketing during loading and unloading helped produce nice clean metal in 77% yield @ the 50 g (CsCl) scale. Yield is a bit lower than reported (90-98%).

As soon as I get my oxygen cylinder refilled, I'll be good to go with ampoules.

clean sm.jpg - 68kB

[Edited on 22-12-2011 by Zan Divine]

blogfast25 - 22-12-2011 at 06:45

Wunderbar!

Where did you get your Li from this time? Still virgin Li batteries?

I look forward to your experiences with a (plastic?) glovebag and a burner to seal the ampoules! ;)

Zan Divine - 22-12-2011 at 07:47

I bought the Li this time, from GalliumSource in Ca. I've never found a better source for Li, Na or K than these guys. They pay the Hazmat fee and prices are very reasonable.

Now that the metal is clean, I'm rethinking my handling plans. Realistically speaking, I may get the glovebag atmosphere clean enough to handle the molten metal, but maybe not. So, given the ease of keeping Cs liquid, I'm wondering if an all-glass syringe, similar to those I've always used to transfer organolithium reagents, might not be the best strategy. Simply prepare argon-filled ampoules with rubber septa, and use the syringe to transfer from a septa-sealed flask of Cs under a slight positive pressure of Ar. The only exposere to air would come at the very tip of the syringe needle and hopefully any oxide, hydroxide or possible (?) nitride would be wiped clean upon piercing the septa on the ampoules.

Considering all the factors, I can probably get a cleaner product this way.

I cannot, unfortunately, redistill the metal in an all glass apparatus. This requires a better vacuum than I can attain. The original workers used diffusion pumps to get there. The original paper I worked from (the patent) claimed 99% purity as singly distilled. I've seen commercial samples that analyze at 99.5% and they, too, wet glass like mine. Only redistilled material above 99.5% (typically 99.9%) beads up on glass. surfaces.

This marks an accetible compromise to me. Only with additional manpower, equipment & time could I go from 99% to 99.9% and, truthfully speaking, collectors are forced, more commonly than not, to accept group 1 metals with relatively thick oxidation layers. Except in an ampoule, who ever sees bright silver, shiny K? Or Na (for more than tens of seconds, anyway)?

This material is bright and shiny, slightly golden-hued due to imperfect O2 exclusion, and I think this is a good compromise.

It kills me that my O2 cylinder will be out for weeks. I sent it for hydrostatic testing with the refillers....out of state! I had no choice. It's been > 10 years since the last one and they tell me that I'm not allowed to own a K cylinder and they won't simply swap for a full one. They will, however, refill the one I "own" ( It's been in my posession >15 years. You're damn right I own it insofar as no company is going to get it back only to charge me $5 rental/month). Legal disclaimer...this paragraph is fantasy. No responsible person would keep one of their cylinders just to save $60/year....would they?

blogfast25 - 23-12-2011 at 06:46

That makes sense, Zan. You could flush the syringe too, I guess. For 99 % Cs that should really be sufficient and a lot less messier than glove boxes or glove bags...

Fleaker - 23-12-2011 at 19:15

Welcome to the cesium club! As congratulations, I can send you RbCl so that you can make that as well. I have a 50 or 100 g bottle to spare. I have a spare diffusion pump too, as well as a kg or two of CsCl; what I don't have these days is the time!

Your apparatus is VERY similar to what I have used, except I used SS316 for the 24/40, a tube furnace, and a sealed swagelok 1" tube.

You may consider a distillation receiver that allows for vacuum and argon to be applied.

If I do it again, I'll try with lithium (although I worry more about the purity with lithium than with Ca).


vmelkon - 24-12-2011 at 05:27

Was your lithium a block, foil, powder? Did you just put in the CsCl and drop the lithium block on top?

Zan Divine - 24-12-2011 at 10:19

Blogfast25...
Yes, I think this is the answer. Why strive to exclude all O2 from a big fat bag when it's much easier to do it for individual pieces of glassware with rubber septa?

vmelkon....
I just put the lithium (as a few large pieces) into the reactor and dumped the CsCl on top of it. As the Li melts at ~170 C, the solid CsCl should sink into it. Further mechanical mixing is apparently not an issue.
The mixing issue was another reason to opt for Li over Ca as reductant. I am inherently uncomfortable with solid phase reactions and the Ca doesn't melt. I assume the vapors of the volatile CsCl react at the solid-gas interface that is the surface of the calcium but I favor the liquid reductant being in direct contact with the CsCl.

The Li was in the form of a solid ingot as purchased. By the time it was cut and weighed (I haven't found an easy way to cut this gummy metal, it is considerably harder to cut than Na. Saw teeth gum up & knives require a lot of force. A cold chistle is a workable but graceless option) it was entirely coated with Li3N. I read or hallucinated that Li3N reverts to Li when heated, so this wasn't too troubling.

I have had weird experiences with Li manipulation ...contradictory observations. As received, the Li ingot turned black within less than a minute of air exposure. However, if I add Li to a heated steel piston and extrude blobs of melted Li into a collection container, this silvery looking metal is considerably more air-resistant and takes several minutes to begin to darken. Has anybody else made similar observations?

Fleaker....
I found your post both happy and depressing.
The offer of Rubidium is received with real heartfelt appreciation. The generosity of your offer is mind-blowing and I can't thank you enough. I need to look around on this site to see how to contact you directly
Simultaneously, I thought this was a novel bit of basement chemistry but now I realize that others have preceeded me. C'est la vie.
What's left for the curious? Just F, I think. Unforgiving, hellishly reactive and very toxic. I guess I should check and see if it has been done here before.
If I had a diffusion pump I'd love to redistill the Cs and get 99.9%, or better, metal but there are few inexpensive ones on e-bay. Making one from SS (I don't have the ability to melt and form very large diameter pyrex) could be a project in itself.

As far as this run was concerned, the appratus was designed to allow both the application of vacuum as well as argon via a t-joint with appropriate tubes and hose clamps. When the reaction was over and the bomb cool, the appratus was refilled with Ar before removing the flask with the Cs from it.

As soon as I hit the "pay" button for my new glass syringe, I realized that transfer needles were a better option. I had some ~1/16" OD SS tubing laying around. After trimming and grinding beveled needle points on some, I found that I could easily force Hg through the line and into other rubber septa-sealed glassware by gentle Ar pressure. I must have been away from the lab too long since that should have been the first thought. Better late than never, I suppose...

[Edited on 24-12-2011 by Zan Divine]

[Edited on 24-12-2011 by Zan Divine]

Fleaker - 24-12-2011 at 19:02

Zan Devine,

If you look at plastics's post upthread, you'll see that he mentions that Len had made some Cs and had already published the experiment (by that I mean he literally published it in his excellent book).

I think I had beaten Len to it at that point--I did the Cs experiment in 2009 I think, or perhaps 2010. I've yet to write it up, because I was going to do it on the kilo scale and post that. I can recommend some improvements to the collection and re-distillation of the metal. I also have the synth of Rb, black phosphorus (limited success), an excellent method for bromine, and a few other synthetic curiosities to post. Unfortunately, my day job is also one I take home every night and every weekend and my laboratory is busy with projects that make me money, but aren't necessarily fun. I work in the precious metals field.

[Edited on 25-12-2011 by Fleaker]

Zan Divine - 27-12-2011 at 12:03

Hi Fleaker,
Yes, I saw the reference to Len's work earlier.

I'd be interested in hearing any suggestions you may have on the distillation/collection phase of this work. One kilo, huh? That's a lot of money even at the generally agreed upon value of Cs in bulk, namely $10/g.

I've always enjoyed the chemistry of the coinage and platinum group metals. Once you get them oxidized, anyway.
We made a few gold compounds for the NCI cancer program and lots of platinum ones starting from 60 ounces of the metal.

The bromine prep. I favor is the MnO4- oxidation of HBr generated in situ from H2SO4 + KBr. There are so many of them, but at least this one avoids interhalogens.

Black P...interesting! It seems to require rather extreme conditions. Nice when your hobby overlaps with your profession so that you have advanced facilities at your disposal. I'm guessing you didn't do this at home?

Concerning the RbCl you mentioned earlier, you can contact me at Bull8hit@hotmail.com. Or, if you prefer, I'll contact you if you post a method. That's not my usual e-mail so if you do send anything, let me know here so I'll know to check it. Thanks!

[Edited on 27-12-2011 by Zan Divine]

Zan Divine - 1-1-2012 at 10:29

As I needed to handle, purify and (for another outlet), package exhibitable samples of shiny lithium metal, I looked around and found a lot of piecemeal info on the topic and it is assembled, for anyone interested, in this PDF.

Attachment: LITHIUM HANDLING.pdf (64kB)
This file has been downloaded 3933 times


Zan Divine - 5-1-2012 at 17:26

And here is the final commercial product....

cesium sm.jpg - 38kB

haroldramis - 6-1-2012 at 19:01

I see you have them listed on eBay. You also have a purity listed for them(95% for one of them i think). How did you measure the purity of your Cesium?

Zan Divine - 6-1-2012 at 20:03

I have no means of accurately measuring purity. The samples listed as 99% were prepared according to the previously listed US patent and it claimed a 99% purity for the conditions I used. The metal is entirely silver with a trace of golden color. No trace of any visible oxidation beyond that which causes the trace color.
The 95% sample was estimated by visually comparing the relative volumes of the small amount of lightly oxidized material to that of the bulk.
Neither sample is currently listed as I see what I have to do to ship legally.

Zan Divine - 20-1-2012 at 16:47

Quote: Originally posted by Fleaker  
Welcome to the cesium club! As congratulations, I can send you RbCl so that you can make that as well. I have a 50 or 100 g bottle to spare.


Hi Fleaker,
I noticed you read my communications. It's been some time, but I haven't heard back from you. Do you still mean to do this? I have the time and materials to do this, except for the RbCl. I also have people waiting for Rb samples and I keep telling them I don't know where this stands. So, when you can, please let me know. Thanks.

[Edited on 21-1-2012 by Zan Divine]

blogfast25 - 21-1-2012 at 09:47

Quote: Originally posted by Zan Divine  
And here is the final commercial product....


Very nice, indeed. How much is there?

Zan Divine - 21-1-2012 at 12:06

Hi Blogfast25
I've only converted a small portion of the CsCl to metal. And only part of the last batch has been ampouled up simply because I lack an effective outlet due to shipping regulations. I have made about 14 ampoules total. Each contains from 1.4 to 1.7 grams (from 27 mm long to 33 mm long samples in 6 mm ID tubing).

I can only sell locally (and not on e-Bay or Craig's list, it violates their User Agreement).

In the long term, the shipping regulations on the fun things from groups I and VII that I like to sell have changed my plans. I'll still make Rb if I can obtain RbCl (after all, I still need a sample and the apparatus is already built). But production sized white P seems pointless and none of the anticipated cashflow to try to build a F2 electrolysis/purification/packaging setup will materialize.

The F2 synthesis might just have become unnecessary, anyway. A fellow collector sent me a picture of himself holding two fluorine tanks. He has access to pretty advanced facilities judging from other things he offers and says he makes. I am optimistic that he may make some quality samples.

blogfast25 - 21-1-2012 at 13:00

To sell home produced Cs or Rb you might want to consider just doing the producing part and sell your product to various element collector outlets, because setting up the marketing and advertising infrastructure (and for a ‘one product shop’ too) might be even more expensive than sacrificing some of your margins by selling to known middlemen.

To try and beat the ‘known suspects’ (Sigma, Merck etc etc etc) at their own game with just one or two products is also planning to fail IMHO. Just my two cents…



Zan Divine - 21-1-2012 at 15:21

Hi Blogfast25,
I could easily beat the usual suspects for the simple reason that they don't sell to individuals. If they did, Strem ($58/g, 99.5%) and the others would drive sellers like GalliumSource.com ($140/g 99.5%) out of the Cs selling market overnight.

Actually, considering that I'm selling, on average, 1.5g for $50, est. 99% and that my cost for raw materials to make that was less than $1.50, if I could just ship this it would be flying off the shelf and be very profitable. In the time it was e-bay (1 day) it drew lots of attention and an immediate sale, which I refunded.

This was never intended to be a business. It's just how I've keep my net expenditures as I've collected elements to $0. As my remaining targets become more costly, I use products like this to offset the increases.

Well, it's good that I've still got platinum for that purpose. You can't be a synthetic chemist all your life and not have accumulated that. At $80/g I can undersell ....everyone. Except chemical houses and again, they don't count. My beads may not be electron beam melted, but platinum doesn't especially need that since it doesn't react with oxygen at any temperature. Right now it's Pt black but an oxyacetylene flame on the oxidizing side gives very shiny metal. I'll only be asking 100% over spot instead of their 300 - 400%. It may not be the sensation that cheap Cs was, but at least I can go back to shipping from my front porch!





[Edited on 21-1-2012 by Zan Divine]

Fleaker - 21-1-2012 at 16:20

I thought this could go ORM-D if it's small quantities, much like sodium. If not, it'll have to be hazmat pack.

Meant to get back with you, but I've been busier than hell.

Anyway, I'll put the RbCl in the mail. I'll probably put a couple kg of CsCl in the mail too with check for Li.

Past couple weeks I've sold thousands of grams of Pt, but it certainly wasn't for $80/g!

If you want to sell all of that Pt, and any of the rest, let me know.

blogfast25 - 22-1-2012 at 06:35

Quote: Originally posted by Zan Divine  
I could easily beat the usual suspects for the simple reason that they don't sell to individuals.


[Edited on 21-1-2012 by Zan Divine]


I meant by breaking into their traditional, almost captive market: 'institutional science'; they've pretty much got that fenced off.

Zan Divine - 22-1-2012 at 07:58

Hi Blogfast25,
Ahhh, now I see what you meant and I agree. I never expected to sell to researchers or institutions.

The only target audience I had in mind was collectors. They are the ones who get raped for what amounts to ...let's see...$140 + shipping..(GalliumSource pays the Hazmat on orders over $100).. must be at least $160 for a gram of Cs. Absurd.

Another reason I was doing any of this was because of the bond I feel with other collectors. I really enjoy delivering a long sought after sample to a fellow collector. It really works out well for all involved.

[Edited on 22-1-2012 by Zan Divine]

Zan Divine - 22-1-2012 at 08:47

Hi Fleaker,
Thanks for the speedy reply. I was wondering if you were still interested in the RbCl --> Rb thing after I had replied that I simply can't take on the large scale Cs project.

It wouldn't be fair to you for me to accept this piece of work. This type of thing is just a hobby for me. Moreover, my regular job has me on a very unpredictable schedule, while you have a production schedule to keep with your clients. Even if my reactor were larger, ( I'd need from 16 to 20 runs to process 2 kg with my existing setup) the amount of time it would take just makes this unworkable.

And payment in Cs metal would really not do me much good.
I've already got enough Cs (and potential Cs as CsCl) that I'll probably be throwing some of it into water this summer.

As nearly as I can tell, Cs cannot go ORM-D in any amount. I guess the fire hazard is paramount. When I meet buyers, I transport the Cs ampoules in a short length of 1/2" pipe with the ends capped. I consider this to be absolutely bulletproof. Anything that can rupture that $3 overpacking is already so severe that a gram of Cs is a fart in a windstorm by comparison. If only the mail services could grasp this, but it is beyond their comprehension or imaginations. They aren't real receptive to logical arguments. "Rules are rules" is their mantra.

I defy anybody to suggest a reasonable scenario (not something like...what if the pipe has a defect?. They don't.) under which this container could fail. No fire could breach this. It would take a devastating impact to open it. By any reasonable acessesment, this is utterly safe. But, it still can't ship by anything but Hazmat.

blogfast25 - 22-1-2012 at 13:52

Logic doesn’t really come into it, no. In their defence I’d say that they want to keep the rules simple and that postmen aren’t scientists or engineers.

So what company would you use to ship ‘bullet proof’ Cs samples with and how much would it cost?

Zan Divine - 22-1-2012 at 14:30

Therein lies the irony. Despite being impervious to damage & leaks, I still can't ship it USPS, UPS or FedEx.

The authoritie's panties apparently bunch up rather severly on this issue. The same day the Cs went up for sale, I got a friendly warning letter from another collector. I'll reprint part of his two e-mails:

just a heads up i got arrested for shipping sodium through the USPS, i got fined a large amount am now on probation for two years.... I had the FBI and the postal
inspector show up at my house. believe me it is NOT worth it between the fines and the lawyer fees and having it on your record for the rest of your life..

it was bad, they seized my computer and my entire element collection. I got it all back since it wasn't illegal to own those items. i was out the next
morning on a 1000 bond, which only cost me $150. i took a plea for two years probation and a hefty fine which is partially due to the hazmat team coming
to my house to make sure it wasn't dangerous and that i wasn't making any bombs. it turns out i sold the sodium to an FBI agent....it was very scary
to see how much info they had on me. my discovery file was about 100 pages long. it had emails photos of me at the post office, posts on various
forums.

...but overall I'm about 10k in the hole because of it.


Hazmat shipping is inherently incompatible with lower cost items. I've heard different costs for the service, starting at $25. People balk at spending $50 for an item that then costs them another $40 - $50 for Hazmat compliant shipping which includes special packing, the fee & the actual shipping cost.

But Hazmat, to UPS anyway, means "things that are slightly intimidating" instead of "hazardous materials". See the picture below for all the things they don't accept in the "UPS small package division".

Prohibited.jpg - 93kB

"Poisons" fellas, really?! Hmmm...Where is the emoticon with eyes rolling back into the head?

This suggests to me that I can't ship with them. I'll concede that I may be wrong about exemptions simply because I can't say I'm definitely right after looking through 49 CFR. I'm probably going to end up calling them to ask, but I'm not optimistic. I wonder how GalliumSource does it? It's possible somehow...

All in all, I'm more confused now than when I started writing!















[Edited on 23-1-2012 by Zan Divine]

blogfast25 - 23-1-2012 at 07:36

Ouch: 10 k in the hole for practicing a legal hobby. Land of the Free?

GalliumSource must have similar problems: $140 for 1 g of Cs ('Free shipping' my *rse) can only be explained by high shipping cost. Perhaps you should by a gram and see who and how it is delivered to your doorstep?

Zan Divine - 23-1-2012 at 08:25

Actually, Blogfast25, I'm going to just do what I should have all along...just call some postal officials and ask them.

I was quite confused after trying to interpret parts of 49 CFR. You get used, with the internet, to finding your own answers. I have no doubt that I found them. But that's not worth much if you don't understand them.

For what it's worth dept:
Metallium, Inc. lists the hazmat fees for the following;

Group I metals $70
Bromine $35
Hg & Ga $25

It's a little hard for me to see the logic. Br is clearly a greater shipping hazard than Li. And an Hg accident, given the cost of clean up, could argueably be as bad as most of group I. I thought that Ga couldn't ship by air because planes are largely aluminum. So, why is this Hazmat at all if it ships by ground? It sure isn't a real toxicity concern.

One site that ships Cs gives this info:
Shipping Information:
Cesium, 4.3, dangerous when wet, UN1407, PG I

I would have thought that Cs would be "spontaneously flammable". NaOH is dangerous when wet. Hmmm, if they can classify it as merely "dangerous when wet" and it flies, maybe there's hope. This class has some wiggle room if I'm reading my last posted picture correctly.

watson.fawkes - 23-1-2012 at 08:30

Quote: Originally posted by blogfast25  
Ouch: 10 k in the hole for practicing a legal hobby. Land of the Free?

GalliumSource must have similar problems: $140 for 1 g of Cs ('Free shipping' my *rse) can only be explained by high shipping cost. Perhaps you should by a gram and see who and how it is delivered to your doorstep?
Shipping regulations are written conservatively because there are lots of both foolish and venal people that will externalize risks onto the carrier and the public. The hobby is legal, but like it or not, the shipping regulations are strict.

I am pretty sure that GalliumSource is simply rolling the cost of hazmat shipping into the base price of the product. It's essentially a marketing gag to avoid having to educate a consumer about how expensive hazmat shipping really is. That feeling of offense that shipping isn't free, while emotional and not rational, will still cause lost sales.

blogfast25 - 23-1-2012 at 09:22

Watson:

Regulations, like laws (or any other texts), require interpretation. It becomes quite absurd when someone is willing to go to quite extreme lengths to minimise the risk posed by the shipped product and STILL can't find (at least up to now) anyone who wants to do the running and get paid for it quite handsomely! The packaging he proposes is probably safer than a can of Draino conc. H2SO4, as well as shipped in much smaller quantities. This isn't just about safety, there are commecial interests at play here...

Regulations that regulate handling and shipping of small amounts of chemicals for hobby use often resemble a pneumatic drill to crack a peanut with...


[Edited on 23-1-2012 by blogfast25]

watson.fawkes - 23-1-2012 at 09:52

Quote: Originally posted by blogfast25  
It becomes quite absurd when someone is willing to go to quite extreme lengths to minimise the risk posed by the shipped product and STILL can't find (at least up to now) anyone who wants to do the running and get paid for it quite handsomely!
It helps to actually read the regulation. The UPS image posted shows a restriction for "dangerous when wet" materials unless they satisfy 49CFR173.13. That's an easy regulation to go read, and specifies what that regulation considers adequate packaging.

UnintentionalChaos - 23-1-2012 at 09:56

Group 1 metals can't ship by USPS, period, end of story, no matter how well packaged they are. Galliumsource ships group 1 elements by FedEx for a reason. http://pe.usps.com/text/pub52/pub52apxa.htm

Zan Divine - 23-1-2012 at 10:02



A point worth making is the lack of gradation in the fees. Ship 5 g of Na or 5kg...same Hazmat fee. That is a perfect example of an absolutely ludicrous one-size-fits-all rule that probably indicates a certain degree of laziness and short-sightedness among the people who devised the cost structure.

Most other aspects of shipping are graduated, here it's all or nothing. You are never going to convince me that shipping collector-sized samples is in any way equivalent to shipping in bulk. Except for the Hazmat fee.

Of course, if you one of those people who are inclined to see a 2 or 3 gram sealed ampoule of bromine as the same risk level as 1 kg, why would I want to argue? Logic likely doesn't play a big hand in your opinions.

And on that note, I apologize for getting this off on the wrong track. My shipping abilities/impossabilities are not only not of scientic interest, they are boring, as well. I'm not going to waste any body else's time on this subject.







[Edited on 23-1-2012 by Zan Divine]

Zan Divine - 12-2-2012 at 06:00

Quote: Originally posted by Fleaker  

Meant to get back with you, but I've been busier than hell.

Anyway, I'll put the RbCl in the mail.


Hi Fleaker,
I was wondering about the offer you made on 12-23-11 to send RbCl for reduction.
I asked you about it again on 1-22-12 and you said you'd send it.
That was 3 weeks ago and my customers keep asking about Rb. All I can say to them is that a guy on ScienceMadness said he was sending it...
Anyway, If you don't mean to send it, could you please just say so? If that is the case, I need to start looking elsewhere.
Thanks.

[Edited on 12-2-2012 by Zan Divine]

Zan Divine - 5-3-2012 at 14:08

First things first—

I want to publicly express my gratitude to Fleaker for his very generous gift of RbCl. Thanks to his thoughtfulness I will be reporting on the production of rubidium metal in coming weeks.

Yield as a function of mixing

After a half dozen runs with 4 different reactors, I’ve noticed a trend in % yields. Shorter, wider reaction mixtures are preferred over taller, thinner ones. Equally high yields can be obtained with either, but it’s much easier with the former. In all cases, the yields are far short of quantitative when the reaction appears to be over (it isn’t!).

This is what I believe occurs:

1) The heavy, unmelted CsCl settles to the bottom @ ~180 C when the Li melts.

2) They react during the settling process and at the resultant interface. Wider reactors have larger interfacial areas.

3) LiCl starts to build up. It’s heavier than lithium, lighter than CsCl, and probably not very miscible with either one.

4)The rate of Cs production drops off as the LiCl layer thickens and isolates the reactants..

Increasing the heat is counter-productive. Some Li may volatilize and the CsCl layer fuses.

To attain excellent yields, I run the reaction and collect distilled metal until the rate drops off appreciably. The reactor is cooled under vacuum, refilled with argon gas, opened up and the contents at the bottom of the reactor are mashed together with a screwdriver blade. The reaction is restarted and additional product is collected. This process can be repeated as necessary.

A method of physically mixing the reactants during the reaction would be a great improvement to this process.

blogfast25 - 6-3-2012 at 06:08

Excellent reporting there, Zan. Your explanations sound very plausible.

Any luck with the rubidium yet?

And to Fleaker: it's pure discrimination, this donating RbCl to one member and not all of us! ;)

Zan Divine - 6-3-2012 at 07:37

Hi blogfast25,

Thanks, I forgot to mention that the 2nd heating cycle gave as much product as the 1st. The 3rd, and last, cycle gave 25% as much product as cycle one. The point here is that these subsequent cycles are a major part of the yield, not just a small enhancement. When I first tried this out I wasn't expecting much.

Since this technique led to different fractions of the distillate being collected, some observations are possible. Fraction 1 wets glass totally & completely. Fractions 2 & 3 only wet it partially, somewhat similar to pictures I've seen of 99.5% material.

According to the FedEx tracking number which Fleaker so kindly provided, the RbCl is on the truck for delivery today.
I'm going to try to fit in a small scouting reaction within days, I hope.

blogfast25 - 6-3-2012 at 08:34

Quote: Originally posted by Zan Divine  
Since this technique led to different fractions of the distillate being collected, some observations are possible. Fraction 1 wets glass totally & completely. Fractions 2 & 3 only wet it partially, somewhat similar to pictures I've seen of 99.5% material.



You'll eventually have to have your metal analysed by XRF, you know! ;)

Fleaker - 6-3-2012 at 15:24

I'd be glad to analyze it as I have ICP I can use and standards--just make it so that it's in solution already. Part of the delay is moving buildings. It's been a big drag. That and I had some serious health stuff come up that I never saw coming (at least I figured out why things were off in my life!).

Zan, I have probably 3 or 4 kilos of CsCl of my own for making Cs. Sooner or later once things have settled down for me, I'll probably do a kg batch of Cs. I have a pretty big diffusion pump here at work, so I can re-distill the Cs under high vac. If you want yours re-distilled when I re-distill mine, let me know.

I've never tried the lithium method. I do it with Ca flakes/granules and the yield is higher. I wonder if it's just an oxide issue--the Cs and molten Li are acting as getters for residual and trace O2/CO2. That explains why it's better at the end.

Zan Divine - 9-3-2012 at 17:57

Fleaker, I'm sorry to hear about your health issues. The diagnosis sucks but you can hopefully manage it well. The new generation of delivery devices is a lot more user-friendly at least.

I'm guessing that products formed from Li or Cs with H2O or O2 would be less volatile than the metal itself and not miscible with it once it cooled.

Also, I don't believe that we have much loss of Li or Cs due to H2O /O2 for these reasons:

1) An extra half molar equiv. of Li is present at the start and unreacted Li remains at the end of the reaction (vigorous H2 evolution in H2O, no fire)

2) For the last 60 g CsCl reaction, T.Y. of Cs is 47.4 g Cut 1 was 19.6 g, Cut 2 was 18.6 g and Cut 3 was 6.1 g for a total of 44.3 g or 93.5%

Still, there is no denying that some impurity is present and it is surprising that it appears to concentrate in the early fraction.

Just what would that be??

Cesium and rubidium are the most volatile members of groups I & II. Any of the others should be enriched in the latter fractions. I've only taken a cursory look so far, but I haven't run across any azeotropes mentioned for these metals and I didn't really expect to. Perhaps the most likely impurity in the distillate is rubidium (the 17 C higher bp notwithstanding)?

When crude Cs is redistilled (George Brauer's Handbook of Preparative Inorganic Chemistry Vol 1 p 962 ) it is the later fractions that are discarded, there isn't even a provision to remove a forerun if you wanted to.

It could just be that my assumption that my later cuts are purer because they wet glass less is wrong. But, the literature seems to suggest a positive correlation between purity and inability to wet glass.

All of this can be settled by analyses. To get the most mileage out of the least number of tests and to provide a little more insight into the relative merits of both Li & Ca I will go ahead and prepare Rb both ways and then compare yields and purities. The calcium has already been ordered.

Fleaker, I'll contact you when I have materials ready for analysis. Thanks for the offer.

[Edited on 10-3-2012 by Zan Divine]

Dennis SK - 12-3-2012 at 15:03

Hello "Zan Divine"

First, Congrats with your cesium production succes. Nicely done and look forward to see your future improvements.

I'm an element collector as well and for a long time I focused on group 1 element samples.
I've traded cesium for years and heres a few observations;

You talk about cesium price of 10 USD/g , 140 USD/g and so on depending on various things and then compare it to your price. The main thing about cesium is that as you know, cesium is not very expensive to produce. But to produce a sample of high purity in clean ampoules is very expensive.
So, 1 gram of your cesium cant compare to 1 gram of cesium is a clean ampoule.

I've had countless of cesium ampoules between my hands and of all of those I only have 3 ampoules where the cesium are more or less "perfect"
And by perfect I mean very high purity, no wetting of glass etc etc.

So, my experince is that Cs dont really have a "price per gram" , the price is based on quality of Cs and ampoule.

I've just returned from a "buisness trip" With a few 100g Cs and 250g Rb ampoules of very high quality. I will try to upload pictures of them on the forum soon. I will also soon update all my wikipedia pictures of Cs/Rb because I now have much better ways to photograph. (On wikipedia I'm "Dnn87")

Very much looking forward to your future projects. Would like to see you try Rb.
Good luck!

Dennis SK


Zan Divine - 12-3-2012 at 18:49

Hi Dennis,

Your observation that price depends on purity is quite generally true throughout all chemical industries & labs. That's why I've been careful not to compare apples to oranges and have priced accordingly.

However, to most element collectors there actually are generally accepted prices. The price per gram for Cs is quite simply the advertized price of the lowest priced provider that sells to the public and is easily found on the internet.

For most people in the US, that translates to GalliumSource. That means that the per gram price is $140 @ 99.5% and $165 @ 99.9% purity. I've noticed special orders on their website where Europeans have paid even higher prices. Your sources, of course, may vary.

The same goes for the $10/g price in bulk. For very pure Cs (99.99%), and at the 250 g size, cesium costs $2500 from GalliumSource.

The price of 99.8% pure caesium (metal basis) in 2009 was about US$10 per gram according to Polyak, Désirée E.. "Cesium" (PDF). U.S. Geological Survey. http://minerals.usgs.gov/minerals/pubs/commodity/cesium/mcs-...

The upcoming Rb synthesis, which will be done with Li and with Ca, is going to be analyzed. I'm very anxious to get this going, and by the end of this week I expect to do the Li reaction.

Eventually, I'm going to try to redistill a sample of my current Cs in an all-glass apparatus. Using a pressure-temperature nomograph, I estimate that with my pump I'll be able to stay within the operational range of borosilicate glass.

My biggest problem is too many projects at once. I'm also doing a lot of other custom work like the potassium shown below. This sample is 2.5 in long and 5/8 in OD.

front cropped.jpg - 54kB

[Edited on 13-3-2012 by Zan Divine]

Dennis SK - 12-3-2012 at 21:00

Hello.

I agree on your price examples. But Cesium is i tough market to put a price on. Personally I wouldnt compare cesium prices when looking at diffrent puritys/ampoules.
Theres just so much diffrence in Cs depending on the purity.
But yes, I guess the general public just look at the price and dont consider the diffence. But how would they know anyway?

Your potassium looks very good. Nice and clean.

I would like to try ampouling myself soon. But just too busy atm. It should be straight forward to ampoule some of the low melting point metals. Maybe even distill it into ampoules. (vacuum)


Zan Divine - 13-3-2012 at 05:20

Hi Dennis,

Thanks for the comment on the K. I used a method described in "Handbook of Preparative Inorganic Chemistry Vol 1" by George Brauer.

As I couldn't lift the actual text, I've taken a couple screenshots and they are below. I modified the procedure a bit by glassblowing a spherical section in the melting area for larger capacity and by evacuating the tube before starting. It works amazingly well, and for those without the capability to apply inert gases or vacuum, it is unbeatable.

About Cs & collectors...another point about collectors is that for group 1 elements, they are used to having to settle for heavily contaminated samples. Usually no silver color whatsoever is seen. Most Na & K samples look like pieces of off-white marble. This is not to say this is what they want, it's just what's available. Everyone who has wound up with my Cs @ $50 (be it 99% or whatever) knew about GalliumSource but figured, I think, that saving 2/3 of the price and sacrificing 1% of purity was a good deal.

This is not to detract from your comments on Cs, which were good points, but the reality of most collections is that reasonable concessions save enough money to pay for the next sample or two.

We all seem to have the same common grouse...never enough time!













part1.jpg - 25kB part 2.jpg - 55kB



[Edited on 13-3-2012 by Zan Divine]

Zan Divine - 20-3-2012 at 11:16

So...Fleaker...you must think I'm an ass for rushing you on the RbCl and I haven't reduced it still!

It's the SOS....not enough time. I'm oblighed to go where my customers ask me to go and for a few weeks the main thrust has been on the ampoules of K and Na (published elsewhere on this site).

This week has been a blur of activity and Sat. morning the 24th, I'll be leaving for the ACS convention in San Diego (If any of you are there and want to say hi, we're booth 227). That will take most of the week and so my next opportunity to pick this work up will be in a few weeks.

So, sorry for the delay folks. Right now I'm the cat on the proverbial marble floor. Believe me, I'm anxious to start!

Fleaker - 22-3-2012 at 10:36

It's ok! Life happens. I had the opportunity to play a little bit in the lab. Made a little sample set for a nice fellow who inquired. I imagine he'll put them in better bottles!

They're too small to use induction on, so I melted all of them with O2/H2, except of course the Ag. I plucked that out of one of the silver refining cells.
Might make some Pt, Pd, Ir, Ru, Rh Os, and Au gas phase grown crystals soon--I am prepping up for black phosphorus re-trial.


IMG_0972.JPG - 100kB

UnintentionalChaos - 22-3-2012 at 11:33

Quote: Originally posted by Fleaker  
It's ok! Life happens. I had the opportunity to play a little bit in the lab. Made a little sample set for a nice fellow who inquired. I imagine he'll put them in better bottles!

They're too small to use induction on, so I melted all of them with O2/H2, except of course the Ag. I plucked that out of one of the silver refining cells.
Might make some Pt, Pd, Ir, Ru, Rh Os, and Au gas phase grown crystals soon--I am prepping up for black phosphorus re-trial.




If the black P works this time, sign me up for a sample.

Dennis SK - 22-3-2012 at 12:56

Quote: Originally posted by UnintentionalChaos  

If the black P works this time, sign me up for a sample.


Ditto that!

elementcollector1 - 22-3-2012 at 17:12

So, where do I buy cesium? I want some too! :D

bfesser - 22-3-2012 at 21:40

Quote: Originally posted by Fleaker  
Might make some Pt, Pd, Ir, Ru, Rh Os, and Au gas phase grown crystals soon--I am prepping up for black phosphorus re-trial.

I would love to purchase samples of gas phase grown crystals!

Zan Divine - 30-3-2012 at 12:54

Dammit! Dammit! Dammit!

No sooner do I return from ACS than my company has me going to another trade show in San Francisco:mad:

(Did I ever think this was fun?!)

This kicks any further work down the road a couple weeks....:(

barley81 - 30-3-2012 at 13:22

I know the feeling. My school gives so much homework. I barely have time for any experiments. Break is coming up, so I might have some time...

Zan Divine - 30-3-2012 at 17:02

In many cases it isn't even the synthesis itself as much as it is the supporting work that consumes all the time.

On the surface, this thing takes a half day to perform. The reality, my reality anyway, is that it takes several days of support work including;

  1. Trips to the welding company to get argon, oxygen, & welding rods
  2. Trips to the hardware store for various parts
  3. Welding, grinding, cleaning & testing of the reaction vessel
  4. Orders placed for glass tubing, ampoules, glass syringes
  5. The clean-up operations. These aren't trivial. You've got to do a good job for several reasons.

All in all, this half-day reaction is really about a good number of days.

blogfast25 - 31-3-2012 at 05:40

Quote: Originally posted by Zan Divine  
In many cases it isn't even the synthesis itself as much as it is the supporting work that consumes all the time.

On the surface, this thing takes a half day to perform. The reality, my reality anyway, is that it takes several days of support work including;

  1. Trips to the welding company to get argon, oxygen, & welding rods
  2. Trips to the hardware store for various parts
  3. Welding, grinding, cleaning & testing of the reaction vessel
  4. Orders placed for glass tubing, ampoules, glass syringes
  5. The clean-up operations. These aren't trivial. You've got to do a good job for several reasons.

All in all, this half-day reaction is really about a good number of days.


Yeah, I imagine it's not a GRQ or a gold mine. Hard work for your bucks, more like... Don't give up the day time job just yet!

[Edited on 31-3-2012 by blogfast25]

Fleaker - 31-3-2012 at 07:50

Ehh, you just need to make a lot of it, perhaps 2-3 kg per batch, then re-distill it all at once. Let the economies of scale prevail.

MyNameIsUnnecessarilyLong - 15-5-2012 at 23:27

How are you achieving a good vacuum seal between the metal joints? Was the elbow just threaded tightly onto the reactor (presumably with tapered threads?), or did you use some kind of metal gasket or high temp brazing afterward?

Were you able to measure the pressure during the reaction/distillation?

Zan Divine - 16-5-2012 at 06:37

The metal joints were (are) a concern. I wanted a joint compound of some sort and settled on a high-pressure, high-temperature formulation of molybdenum disilicide based lubricant/seal.

The actual pipe fittings were very problematic (to me anyway). They are Chinese in origin (nothing but the best at Home Depot, eh?) and are not the best ferrous products around by a long shot. They tend to give welds and brazes very prone to porosity. I can't tell you how many weld/grind/test cycles I went through to get acceptable vessels.

I did not have the ability to measure the vacuum during earlier work, but I just acquired a McLeod gauge. My upcoming rubidium synthesis will be the first where I'll have pressure data.

elementcollector1 - 21-5-2012 at 19:47

anything new on the cesium sales? XD
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