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Barium Animus

Dan Vizine - 1-1-2015 at 22:08

A while back, I constructed a purge type glovebox. That kind has no purification train, and is like a glorified glovebag. It's 30 gal in vol. and the other day I started it up for the first time. After purging with ~ 50 cubic feet of UHP argon, I set about on two tasks. The first was ampouling lithium, the second was ampouling barium.

The atmosphere inside the glovebox was sufficiently good to allow preparation of good lithium samples. One type was high-purity pellets, another was chunks carved out of oxidized ingots.

So, now I was ready to find out if my expectation that barium was going to be much more challenging than lithium was correct. It was. An atmosphere capable of good handling of lithium was not good enough for barium. Barium is used as a "getter" in vacuum tubes, so small wonder. The barium could be sanded or filed to a silver surface. This turned to a golden color within 2 to 3 seconds. This further aged to a purplish or bluish silver in the time it took to mechanically trim each edge. The faces of the slab were quickly re-cleaned and it was put into a sealed ampoule which was flushed with more UHP argon. The sealed vial is shown below for comparison. It's clearly metallic, it was a degree of luster, although it's muted and purplish.

I'm convinced that tumbling, under argon, in a sealed ball mill, or peanut butter jar, has promise of nicer samples. Cleaning has got to be simplified to exclude even the cleaning process operating across the air/protective medium interface. Simplified to just grabbing the sample, dropping it into an ampoule and evacuating or inerting.

100 g in 10 ampoules (Large).jpg - 393kB

j_sum1 - 1-1-2015 at 23:20

Those lithium ampoules are beautiful!

Are you selling them?

blogfast25 - 2-1-2015 at 05:03

Beautiful Dan.

That golden hue is so reminiscent of slightly oxidised Cs, no?

Bert - 2-1-2015 at 05:32

How do you seal ampoules in an inert atmosphere? Or do you seal outside the glove box?

Dan Vizine - 2-1-2015 at 14:55

Hi j_sum1,
The ampoules with the small shot were prepared for GalliumSource.com. The ampoules with the chunks are available on e-Bay right now. If you or anyone from this site should buy one, mention it in a note and I'll refund $5. Or, just skip eBay altogether and I'll subtract $10.

Hi blogfast,
I had the exact same thought when I saw it. It's also not too dissimilar to watching a piece of polished steel that gets heated in air. Gold at first, but then that blue and brown grows in.! I think that barium may possibly be the most difficult metal to prepare in shiny silver form.

Hi Bert,
I use rubber septa to stopper the tubes, remove them from the glovebox and then seal them.

Dan Vizine - 2-1-2015 at 21:40

Well, no sense in internally debating this any further. I put this together from VCR, car, printer & toy parts. I ordered a pound of SS 302 shot. In less than a week, we'll see if this has any merit.

blogfast25 - 3-1-2015 at 05:45

Ti I've also seen with this golden sheen. Presumably it's an oxide coating only a few atoms thick.

argyrium - 3-1-2015 at 20:11

Very nice work, Dan. Thank you for posting for all of us to see.

And, BTW, the first photo of the sealed ampules would look very nice on a Christmas tree!

[Edited on 4-1-2015 by argyrium]

Dan Vizine - 7-1-2015 at 16:32

Thanks, argyrium.

Well, here's the first update on this ongoing attempt to prepare silvery barium metal via tumbling. It seems there's more to the construction of an efficient ball mill than I realized, and a subtle balance of forces determines the outcome (speed, tilt, media drag and weight, shapes of media and workpieces, etc.) . It was my intention to try small SS 304 pellets. I made a bunch from some ~0.2 inch diameter wire and threw 3 of the God-awful filthiest, largely black and crusty pennies I could find in there and spun the mill up. The media refused to climb the glass wall, too smooth. Let me take a second to state the [now] obvious...the media needs to climb as high on the revolving wall as possible, ideally succumbing to gravity near the top, in order to fall the greatest distance to impact the workpiece. A rubber wall lining fixed this. Second run was three+ hours long and it took one of the [not pictured] mystery-encrusted specimens to the single partially-cleaned picture seen below. Interestingly, the SS pellets were now polished and shiny compared to their original form, below. I decided to investigate another media. I hammered some old fused alumina into pea-sized chunks and strained out fines and added a putrid nickel. About 60 minutes of milling [with no SS pellets present] gave very dusty samples which rinsed off to give the cleanest sample below. These were short runs, but so far I believe:

1) Hard samples clean better than soft ones.

2) Alumina is many times faster than SS. A mixture deserves a look.

3) Sample geometry is important. The round coins often rolled along the inside walls and avoided many impacts.

4) Since hardness matters, a good stand-in for Ba is needed. Pb is nearly as hard and so I made some rectangular blocks to approximate the barium (below).

Back to the tests....

[Edited on 8-1-2015 by Dan Vizine]

phlogiston - 7-1-2015 at 16:47

Typically, the best speed to run a ball mill at is 65-75% of the 'critical speed', which is the speed at which the media is not tumbling but held fixed against the wall all the way round by centrifugal force.
There exists a simple formula that relates the media size to the ball mill container size, which (since it appears you tend to plan experiments really well beforehand) you most likely have found out already.

You may also want to look into using a mixture of media of different sizes.

Dan Vizine - 7-1-2015 at 17:23

Actually, if I planned well enough, I wouldn't be re-designing now. The prototype was really supposed to be a proof-of-concept, so I guess that's nearly an utter failure, so far. I should really try to find out if ball milling is even applicable to softer metals. Just maybe taking a small motorized ss wheel into the gb and working harder to maintain low residual gasses in the atmosphere will have to be the answer.

Edit: Tumbling Pb with alumina chunks is a dog. The results are shown below.

Tumbling with SS in progress, expectations aren't high. I suspect a much softer medium may be needed, or perhaps just a smaller one, like dry sand.

[Edited on 8-1-2015 by Dan Vizine]

halogen - 7-1-2015 at 17:24

Barium you claim was used as a getter. Could you not use a sacrificial amount to... get? Not efficient enough, or too slow I guess. Just an idea.

Another, you worked inside a glove box. Purged but not perfect. What about a glove balloon? Not a idealized spherical ensemble, but inflatable nonetheless? Squeeze out the oxygen first. I read PVDC has desirable barrier qualities.

Dan Vizine - 7-1-2015 at 18:57

Actually, the first layers rubbed off the barium were the initial impurities and the sacrificial layer. One problem may just be surface morphology as the poor looking Pb sample became the below just by burnishing with no material removal.

With additional purging, the gb will reach the same purity as UHP gas, about 5 ppm O2. This is the way to go. It will be quite dry as it passes through a 30 inch zeolite column before the box. The box is sealed on an order equaling commercial units. If I pump the gloves up at night, they are still up 24 hours later. But, why not? I have almost no leakage points, no doors, no KF-40 ports, etc.

Molecular Manipulations - 8-1-2015 at 13:11

Nice pictures Dan.
Why not run the argon through a "getter" first?
A tube with lithium turnings will work fine.
Is the impurity nitrogen or oxygen, or both?

[Edited on 8-1-2015 by Molecular Manipulations]

Dan Vizine - 12-1-2015 at 16:02

The likely impurities are 2 ppm O2, 2 ppm (theoretical min), a few ppm N2. Unless H2O exceeds 5 ppm, Li is immune to O2 and N2.

Tumbling experiments have been many and varied. All failed.

A small motorized SS wire brush and a better atmosphere are now the intended route.

Bert - 12-1-2015 at 16:13

From a past life where I worked on very high vacuum systems:

We used Ti to scavenge the last tiny bits of gas. It reacts with both N2 and O2 QUITE well when hot-

The systems I helped build had little heated pots of Ti set up with a charge on them, with a charged grid to accelerate stray gas molecules in the correct direction to hit the Ti, physically STICK into the surface and react there. Yours truly built the power supplies and fabricated the electronics chassis.

Ion pump

[Edited on 13-1-2015 by Bert]

Dan Vizine - 20-1-2015 at 10:25

Hi Bert and Molecular Manipulations,

I can fully appreciate everything you're saying, I've been considering a lower tech form of scrubbing the atmosphere, simply stirring a small beaker of liquid sodium potassium alloy in the glovebox before use should scavenge oxygen and moisture. But they won't touch certain other gases, like nitrogen.

Lithium is certainly an interesting scavenger choice as it reacts so readily with nitrogen, and you might think that an atmosphere that had been exposed to freshly cut lithium pieces for five consecutive hours (without them darkening at all) might be clean enough, but it isn't. Not by a long shot. If I had to make a very rough estimate as to the time it takes a sample of the two freshly cut metals to be completely covered with a darker coating I would have to say that darkening is at least 10,000 times faster for barium versus lithium. The barium went from silver to gold in a couple seconds, and blue/brown shortly after that. Lithium remained utterly shiny in my glovebox atmosphere for the five hours I was working. I am utterly astounded by this material. It is far more sensitive to atmospheric contamination than liquid cesium, rubidium, potassium, sodium, lithium.

I think the dark color on the barium is probably less indicative of oxygen than something else, barium left in the air turns primarily white.

And the white elephant in the room, that I haven't mentioned yet, is the fact that when you commission a new glovebox, the copper adsorbent is really quite quick and efficient at removing oxygen. A glovebox can be started one day, and by the next day you are at sub part per million levels of oxygen. You can even just purge down to a few ppm O2 without circulation with a liberally available gas supply, like LO2. This isn't the case for water, not by a long shot. It has taken anywhere from 2 to 3 to as many as five days of continuous circulation before all of the adsorbed water on anything you've put into the glovebox, and the glovebox walls themselves, has desorbed in order to be scavenged.

I know that my glovebox has an absolutely exceptional leakage rate. It's better than commercial units. I can pump the gloves up and two days later they have not sagged, I'm not saying I have the most superior technology in the world, merely that my glovebox has very few openings to the outside world. My supply gas is what it is, the only improvement I could make would be pretreating it with powdered barium . But even if I did that, without a glovebox that operates continuously long enough to get dry (< a few tenths of a ppm) inside, maybe I'm just banging my head against the wall. I can't believe I'm being defeated by a group 2 element.

Incidentally, the use of a rotating stainless steel wire brush was not particularly effective at all. It was almost as though the grooves the wires cut reacted faster. Larger surface area. It certainly gave worse results than sandpaper or a file. Since metals generally become more tarnish resistant the more smooth the surface is, perhaps fine grade sandpaper will at least give a surface that darkens at a slow enough rate so that I can get samples that are only silver and gold into a vial. I don't harbor any illusions that I am going to come up with brilliant silver barium metal anymore.

This is proving to be a real challenge. The current score:

Barium 2

Dan 0

[Edited on 21-1-2015 by Dan Vizine]

Dan Vizine - 22-1-2015 at 21:15

Probably, if I ground up a bunch of barium and let a large tray sit in the middle of the glovebox overnight or longer with the box at maybe 5 or 6 mbar argon and with a small circulation fan, it might make the atmosphere good enough.

This isn't over, Barium.

Molecular Manipulations - 22-1-2015 at 22:17

Quote:

Originally posted by Dan Vizine
Li is immune to O2 and N2.

Oxygen yes, forgot about that, but it reacts readily with nitrogen, or must water be present for that as well?
Heated lithium should work, it reacts with oxygen and nitrogen, and is much cheaper than barium.
I would bet that the main impurity is nitrogen, just like lithium nitride is dark but the oxide is colorless, barium is probably similar. Of course just because nitrogen is present doesn't mean oxygen isn't.
Either way, I suggest running the argon through a tube of hot lithium turnings/bubbling it through liquid lithium before it enters the glovebox. That would be faster and more efficient no? Or would that be too hard to incorporate in the system?
I'm shocked that it reacts that fast in such conditions,
truly amazing. It reminds me of when I tried to make barium oxide.
I heated barium nitrate to red hot for 20 minutes until it stopped evolving nitric oxide and oxygen, then quickly crushed the fused mass and ampuled it under nitrogen while still hot, within 40 seconds. I made three ampules this way, and tested one the next day. Turned out, based on pH tests and quantity of carbon dioxide evolution upon reaction with acids, it was at least 90% barium carbonate.
Still haven't tried that again.

Dan Vizine - 23-1-2015 at 08:16

Quote: Originally posted by Dan Vizine

A glovebox can be started one day, and by the next day you are at sub part per million levels of oxygen. You can even just purge down to a few ppm O2 without circulation with a liberally available gas supply, like LO2.

No it can't. LO2 would be a poor choice. How about LN2, you senile bastard?

Bert - 23-1-2015 at 09:42

"Ti, nymphomaniac of metals. Get it hot, and it will combine with ANYTHING!"

If you're going to try Ti, you will need to heat it - Pretty non reactive stuff to atmosphere at STP. Even the finest pyro grades I have seen offered for use in igniters can be (relatively!) safely opened in atmosphere.

Powdered Zirconium is a different kettle of fire! Packed in water, it can settle to the point where so little water remains between the particles it is pyrophoric immediately on being scooped out of the jar.

As near as I can recall? Our high vacuum cleaning procedure was:

Start with large rotary pumps, proceed to special high vacuum pumps. With a good vacuum in the chamber, de-sorb gas & contaminants from walls: We would bake walls with heat tapes applied to exterior and the whole outfit wrapped in insulation, heating while using an ion pump to "get" whatever molecules came off the interior walls-

What's the glove box made of? Can you bake it...

[Edited on 23-1-2015 by Bert]

Praxichys - 23-1-2015 at 11:20

Maybe make a big coil of Ti wire (lots on eBay) and hook it to a variac. Let that sit red-hot for a while and see if that does anything. Just keep that hood cool.

Maybe build a scrubbing unit with a blower, the titanium element, and then a gas cooler. Putting a few kV DC bias between a screen aft of the blower and the titanium coil could help electrostatically capture a lot of stuff too.

Just some thoughts.

Dan Vizine - 23-1-2015 at 13:36

Bert and Praxichys,

All great suggestions and ideas. It's the kind of quality stuff I've come to really enjoy from you guys, along with blogfast 25's thoughts and some others.

My glovebox is glass, with polyurethane, PVC, and silicones included. Gentle prolonged baking is possible. In fact, let me show you what I'm working with:

A 20 or 30 gal fish tank was purchased for the main glovebox body because they don't leak, by definition. A sheet of 1/4" polycarbonate (Lexan) was cut to fit the top opening snugly. All interior joints (and exterior too, for the plastic top rim anyway) are sealed with continuous beads of silicone or polyurethane sealant. Metal tape (the only gas impermeable tape) then goes over all joints as insurance. Any wrinkles form potential leakage pathways, so be meticulous. You should note that silicone and polyurethane adhesives and sealants are not 100% resistant to diffusion of oxygen. That's why I used the metal tape over them anywhere possible. Otherwise, thick applications are beneficial and the best you can practically do.

There are no doors, loading and unloading is done through a gloveport. The gas connectors that run through the Lexan have large flat washers soldered to them in a leak proof fashion. The back sides of the washers are fitted with rubber gaskets and everything is sandwiched together and tightened down while the silicone adhesive is still wet, silicone is also applied between the rubber washer and the Lexan. There are a total of seven holes in the Lexan, two for electricity, two for gloveports and three for gasses.

I've given different estimates as to how long the gloves will remain up, if you're glovebox user, former or present, you know exactly what I'm talking about, except that commercial glove boxes open their little electronic solenoids to let gases in to maintain pressure a number of times per hour. You also know that the frequency of refill is somewhat of a good indicator of the leakage rate of the glovebox. Now, obviously I cannot measure my glovebox pressure without instrumentation. The most accurate way I can detect significant change is to inflate the gloves it till they are just self-supporting, not too much more. You know, sticking straight out but not fat.

The longest I've tried this test is for two days, and there was no sagging. That being said, my basement is not exactly a thermostatically controlled environment, but I guess you'd have to say this is a pretty good leakage rate. I am somewhat amazed that the scrap pieces of lithium that I got when I was working in the glovebox while it was in its best shape, and which were simply dropped into a glass bottle that has a all metal top and sealed with about 10 layers of Parafilm, are still bright all these many days later. Admittedly, I once thought lithium was a high benchmark, while now I realize it's mediocre. As long as I don't need to open that bottle it will be very interesting to see how long the shine lasts.

A note about the gloveport construction. The PVC pipes of an appropriate diameter were cut a few inches long and sealed into the polycarbonate with polyurethane adhesive. Then the outside edge of the polyurethane tube which protruded outwards was given a layer of one quarter inch gum rubber whose ends were firmly attached together in a butt joint with cyanoacrylate. This band was stretched and glued on to the PVC pipe. Gloves go on over this. Don't make the mistake of putting a worm-drive gear clamp right on top of gloves. You're just asking for a rip. You need to make another rubber ring (butt seal with cyanoacrylate, not overlapped). This time I used 0.06" butyl, to go over the gloves before the clamp is tightly applied.

Gas escapes from the glovebox through an oil filled bubbler, and I've come to purge with about 100 ft.³ of gas before use. According to the purge chart, it's not going to get much better. My vol. is a small fraction of a cubic meter. Let's see, it's about 3 cubic feet, 1 X 1 X 3,... so I guess it's 20 gal?...whatever... it's only 1/9 of a cubic yard, so less than 0.1 cubic meter. It get's purged with over 30 times its vol to start, and during several hours work, probably another 30 to 60 vols of gas. The lines were reconfigured to bring argon in at the bottom and exit at top for obvious reasons.

My gloves are quite old, ridiculously so, but they don't leak. They are 30 mil. I've developed the perfect seal for leaking gloves. it's a combination of cyanoacrylate to fix the hole and plastic tool dip (like from Home Depot).

[Edited on 23-1-2015 by Dan Vizine]

[Edited on 23-1-2015 by Dan Vizine]

Aha

Praxichys - 23-1-2015 at 14:38

Hey, check this out:

http://pubs.acs.org/doi/abs/10.1021/am900206e

Outgassing of Oxygen from Polycarbonate
Sung In Moon , L. Monson and C. W. Extrand *
Entegris, Inc., 3500 Lyman Boulevard, Chaska, Minnesota 55318

It looks like polycarbonate is susceptible to permeation and adsorption by oxygen. Baking while scrubbing may help, or (unfortunately) replacing the PC with stainless steel or glass sheets.

Nice glovebox, by the way.

[Edited on 23-1-2015 by Praxichys]

Dan Vizine - 23-1-2015 at 22:30

Quote: Originally posted by Bert

The systems I helped build had little heated pots of Ti set up with a charge on them, with a charged grid to accelerate stray gas molecules in the correct direction to hit the Ti, physically STICK into the surface and react there. Yours truly built the power supplies and fabricated the electronics chassis.

Some of the sputtering chambers that I see have a roughing pump, followed by a turbomolecular pump and the final step, a grid through which liquid helium flows. There's a little red unit about the size of a medium shop-vac that recyles the helium, actually re-condensing it from gas. They also charge the grid. It's fairly fast, considering the goal and the large size of the chamber. The doors were large enough that the construction material was 1" thick SS plate. I has truly impressed.

Your vacuum was probably better still. There were no getters used because, after all, it is a sputtering chamber. I think they'd cause cross-contamination, but I'm only guessing.

Dan Vizine - 25-1-2015 at 17:10

As a yardstick of progress, I compare my samples to the best larger ones that I can find, the ones at Smart-elements. Although, their largest was (they are out of stock) 3 grams, while my smallest is about 6 g.

Comments on comparisons? Theirs are kind of pricey, like 30 - 40 dollars/g. I don't know why it couldn't be a third of that?

My first "brighter" looking samples were sunlit, the last incandescent, so bear that in mind. My first two pictures look wayy more silver than I actually see them, but it does shows that they are quite reflective.

Their samples look almost tumbled, what do you think? Yes, I'm still kinda' beating that horse. I'm surprised a commercial enterprise doesn't have a glovebox capable of better than this. Maybe they use M. Braun?

[Edited on 26-1-2015 by Dan Vizine]

j_sum1 - 25-1-2015 at 19:14

I am loving this Dan. I think your samples look superior. Larger, brighter and I prefer the cut look to the rounded edges -- even if tumbling could potentially produce a brighter finish, they haven't achieved it.

For my element collection, Ba is a bit further down the list. But if you get your methodology perfected then I might reprioritise. Count me as a potential customer!

Dan Vizine - 20-11-2016 at 10:29

It's been some time since I've given much thought to shiny Ba metal.

Interestingly, our company is currently designing a custom glovebox for a university in the SE. A requirement is to handle metallic Ba metal and keep it clean. I’ve been involved in devising modifications to improve the normal glovebox atmosphere and so I've had reason to consider the root of the issue in more detail.

The challenge is rooted in the actual mechanism of the discoloration. When I examined the best Ba sample that I've made, there were two simple observations that seemed significant. The metal surface is a multicolored affair and it looks like a metallic surface, smooth and shiny, not dull. The pattern of colors resembles oil on water. And, similar to the oil-water system, this must be caused by a variation in thickness of the coating. But this must be on the same scale as the wavelength of light. The sad truth is that barium tends to react, when only trace impurities are around, to give a highly refractive surface.

This is different than Cs, where impurities dissolve into the metal, or other alkali metals, which only lose a small amount of reflectivity when the surface hosts trace impurities, and no additional colors are produced.

IMHO, barium is uniquely poised, along with strontium, to provide the most difficult challenge among all of the stable, naturally occurring elements to successful manipulation without degrading the surface appearance.

Has anyone ever seen a silvery sample of barium metal in an ampoule? I can't even find a picture of it.

froot - 20-11-2016 at 11:27

Just a thought.
The 2 samples above look from their textures cast from molten state or electro refined/CVD (if that's even possible), suggesting they have not been in contact with other metals or their oxides/hydroxides in passivation layers.

aga - 20-11-2016 at 12:15

Interesting stuff. Not read this whole thread before now.

So the main challenge is to manipulate the Ba without letting anything get near it, like in a perfect vacuum ?

Got an idea lying about in the back of my mind (such as it is).

Something to do with a cast aluminium reactor vessel that can be sealed, heated and vacuumed, with actuators inside to move things around.

Lose the transparent materials, also the hand-holes to make it simpler and easier to build.

Maroboduus - 20-11-2016 at 15:21

Aren't barium animus what they give you at the hospital so your colon X-rays are easier to read?

Dan Vizine - 21-11-2016 at 11:53

Quote: Originally posted by j_sum1

Those lithium ampoules are beautiful!

Are you selling them?

Hi j_sum1,

Those were made for Galliumsource a number of months ago.

Dan

Dan Vizine - 21-11-2016 at 12:08

Quote: Originally posted by froot

Just a thought.
The 2 samples above look from their textures cast from molten state or electro refined/CVD (if that's even possible), suggesting they have not been in contact with other metals or their oxides/hydroxides in passivation layers.

Hi Froot,

I've been looking for hints of their method in the shapes of the samples. Yes, they have that smooth look of something solidified from molten metal. But still, they are far from acceptable samples. I wonder how Ba looks right after distillation by the producer? I mean, does the first fraction effectively scavenge all impurities so that subsequent matl. is clean? I guess it doesn't matter, they have to collect it, it can't stay silver.

RGB in England is putting together a specially designed glovebox (at least a year ago) to make clean samples. They haven't delivered yet. They aren't using hot Ti to scavenge N2 so I have some doubts if it's possible.

Dan

Dan Vizine - 21-11-2016 at 12:21

Quote: Originally posted by aga

Interesting stuff. Not read this whole thread before now.

So the main challenge is to manipulate the Ba without letting anything get near it, like in a perfect vacuum ?

Got an idea lying about in the back of my mind (such as it is).

Something to do with a cast aluminium reactor vessel that can be sealed, heated and vacuumed, with actuators inside to move things around.

Lose the transparent materials, also the hand-holes to make it simpler and easier to build.

Hi aga,

I know what you're thinking. It's also my fear that only a sophisticated purpose-built device may be enough.

Dan

Dan Vizine - 21-11-2016 at 12:50

Quote: Originally posted by blogfast25

Beautiful Dan.

That golden hue is so reminiscent of slightly oxidised Cs, no?

Hi Blogfast,

That bronzy (holy shit, that's a real word?) look is reminiscent. Strange little story, probably 15 or 20 years back, I prepared a drug for NCI. It was so unusual that out of the thousands of molecules I made, it stands out. It was a disubstituted benzoquinone, that's the only details that I recall, and it had no metal in it. But it was just like bronze powder..exactly. No hint of any other color. I didn't even know that was possible given that gold isn't a color, but more a byproduct of relativistic quantum effects.

Dan

aga - 21-11-2016 at 12:54

I wasn't thinking 'sophisticated', just 'purpose-built' which could turn out as simple as a tennis-ball sized aluminium casting and a few magnets to move the actuators from the outside, eliminating the need for any holes to do stuff.

Basically a box (probably spherical) with the minium size and abilities to do what you want and one hole to put the stuff inside and also to suck the air out/introduce argon.

If it's Aluminium, easy to make, easy to heat to say 300 C to drive out any water without compromising the structure.

Lob in your material, suck out the air, let the 'getters' get whatever they're supposed to get from the very small volume, then process the material as the design required using the ouside Nd magnets.

I dunno if that would work. Just an idea.

Also sounds like great fun to make !

If i can possibly make an apparatus that helps, let me know and i'll try to make it and send it if possible.

It would be awesome for an amateur effort to reliably make shiny ampouled elemental Barium.

The septum idea before sealing the ampoule sounds like a good do-able solution.

Dan Vizine - 21-11-2016 at 12:59

Quote: Originally posted by Maroboduus

Aren't barium animus what they give you at the hospital so your colon X-rays are easier to read?

And that, my friend, was the true inspiration for the tongue-in-cheek title.

Heavy Walter - 21-11-2016 at 13:14

Hi Dan
I followed your comments about the frustrating struggle to get shiny barium chunks.
What about heating in vacuo in order to dissolve the dark layer into the barium mass?
At 727°C it melts so it is not too high temperature for a small oven in quartz tube with a flange to a vacuum system.

Dan Vizine - 21-11-2016 at 13:14

Quote: Originally posted by aga

I wasn't thinking 'sophisticated', just 'purpose-built' which could turn out as simple as a tennis-ball sized aluminium casting and a few magnets to move the actuators from the outside, eliminating the need for any holes to do stuff.

Basically a box (probably spherical) with the minium size and abilities to do what you want and one hole to put the stuff inside and also to suck the air out/introduce argon.

If it's Aluminium, easy to make, easy to heat to say 300 C to drive out any water without compromising the structure.

Lob in your material, suck out the air, let the 'getters' get whatever they're supposed to get from the very small volume, then process the material as the design required using the ouside Nd magnets.

I dunno if that would work. Just an idea.

Also sounds like great fun to make !

If i can possibly make an apparatus that helps, let me know and i'll try to make it and send it if possible.

It would be awesome for an amateur effort to reliably make shiny ampouled elemental Barium.

The septum idea before sealing the ampoule sounds like a good do-able solution.

The idea is entirely logical and one that I've thought about.

I think the sophisticated part comes in when you have to be able to exert enough mechanical force to cut and shave the metal. So, then you come right down to it...you either incorporate gloves (and just maybe that is enough to cause it to fail) or you make the mechanical parts capable of grabbing crude chunks, cutting and cleaning and all of the manipulations required to do that.

My thought is to just distill the barium directly into a quartz ampoule. I need to do more research on that idea. I'll have the quartz and an oxy-hydrogen torch from my current black P project.

Dan Vizine - 21-11-2016 at 13:24

Quote: Originally posted by Heavy Walter

Hi Dan
I followed your comments about the frustrating struggle to get shiny barium chunks.
What about heating in vacuo in order to dissolve the dark layer into the barium mass?
At 727°C it melts so it is not too high temperature for a small oven in quartz tube with a flange to a vacuum system.

Whoa!

Now there's an idea that has never occurred to me. It has the feature that I think is most important, simplicity. Every manipulation is just another opportunity to fail.

Since this never crossed my mind, I don't know the fundamental answers about solubility and stability that need to be examined. But a Kugelrohr of quartz that heats to 700-800 C is really attractive.

Whether for straight up distillation or dissolution of impurities into the bulk, this is an intriguing idea.

Dan Vizine - 21-11-2016 at 13:28

God, you just have to wonder...is a two-stage vacuum pump clean enough? There is always a trace of oil vapor in the evacuated space. How much is too much? Not an answer that is likely to be found without trying it, I think.

[Edited on 21-11-2016 by Dan Vizine]

aga - 21-11-2016 at 13:44

Try and try again, and enjoy !

Finding stuff out is wonderful fun.

Edit:

If a space is small, how about attaching a tube from it to an enclosed reaction that rips oxygen out of the atmoshere ?

Ditto any other unwanted contents of the reaction vessel.

A vacuum isn't the only way to rip stuff from the atmosphere, especially if that volume is small.

[Edited on 21-11-2016 by aga]

Heavy Walter - 21-11-2016 at 13:48

I am used to work with diffusion and turbo pumps.
Also I understand that they are not always at hand of all amateurs.
Probably a two-stage mechanical pump and a cold trap to stop oil backstreaming could be enough.
Other approach could be no vacuum at all. Only an inert atmosphere, with ultapure argon.

Dan Vizine - 21-11-2016 at 14:25

It's obvious that only quartz will suffice here. Trying things over and over is one thing in borosilicate, entirely another in quartz.

Quartz can effectively be baked in vacuo to give a very, very clean surface. The Ba will already have oxide and nitride, so any residual O2 and N2 after pumping will only be scavenged during heating of the Ba.

I have UHP argon, but this presents a problem. The bp of Ba will be excessive.

The vacuum needs to be good enough to lower the boiling point of barium to a reasonable level, and it must be clean. Trapping is the obvious answer.

Heavy Walter - 21-11-2016 at 14:55

so, are you able to run a test?

careysub - 21-11-2016 at 16:25

I had always heard that the shiny stuff at the end of an old time vacuum tube was usually barium, evaporated as the "getter".

This provides an account of how that barium getter was created:
https://en.wikipedia.org/wiki/Getter

It used barium azide that was decomposed through induction heating, with the resultant nitrogen pumped out. They were using ordinary glass tubes for this. Perhaps you could manage to coat the entire inside surface of an ampoule.

Due to the specifics of the described process, I suspect that any ordinary vacuum tube with a shiny getter really is barium.

Dan Vizine - 21-11-2016 at 19:49

Quote: Originally posted by Heavy Walter

so, are you able to run a test?

Not yet. I'm acquiring quartz tubing and an oxy-hydrogen torch presently, for a black P project.

Right now, this is just in the early exploratory stages.

Waiting until our client starts his Ba work in his new glovebox should give me some invaluable practical info.

Careysub,

Yes, that is almost always barium. I believe cesium was also used at one point, but barium is probably superior.

This passage is interesting:

Barium's industrial applications are limited because of difficulties in use. Usually barium is placed into a protective shell made from another metal or used as an alloy. Sometimes barium is obtained directly in the apparatus it is supposed to be used in by reaction of barium oxide with aluminum. Barium alloys with magnesium and aluminum are used in high vacuum apparatus as a residual gas absorbent (getter).

aga - 22-11-2016 at 09:26

Quote: Originally posted by Dan Vizine

I think the sophisticated part comes in when you have to be able to exert enough mechanical force to cut and shave the metal

No idea how hard Barium metal is, but have an idea how Levers, reduction gears etc work to increase the Force applied to items.

If it's not as hard as steel, some small, magnetically operated machine should be able to shave it.

I do not know if Ba would react with the elements present in steel.

If it does, that idea would not work at all.

Dan Vizine - 22-11-2016 at 15:29

Quote: Originally posted by aga

Quote: Originally posted by Dan Vizine

I think the sophisticated part comes in when you have to be able to exert enough mechanical force to cut and shave the metal

It could probably be handled by clean, dry steel tools at room temperature. And, I imagine that any impurities adhering to the tools will end up in the Ba. Ba, btw, is a bit harder than lead.

It's my present view that only simplicity can yield good results.

The only question in my mind is how, exactly, to do it.

I won't know how good I am at working quartz tubing until I actually do it.

The apparatus needs to be simple. You can do amazing things with a straight tube with constrictions. I process Na, K, Tl, and Pb that way. Pics of the higher melting are shown, Pb first and Tl sitting on a magazine cover. It's interesting to see these metals as shiny & silvery.

The conditions are demanding:

Barium is a silver-white metal, not as soft as lead, and of density 3.78. It melts at about 850° C, is volatile at 950° C, and boils at 1150° C in vacuo.

But, working at modest diameters (maybe 16 mm, certainly 10 mm) and with thick walls (2 mm), maybe I can work this out. This is the first time that I feel I have a real shot at this. In fact, black P just became less interesting.

How much better it is to make a unique product!

I wonder if I can plunder the available literature on getters to any practical advantage?

[Edited on 22-11-2016 by Dan Vizine]

Maroboduus - 22-11-2016 at 19:21

This is a fascinating thread.

Sounds like getting the surfaces clean without their re-tarnishing as you work is a big part of the problem.

What if you had a container of some liquid that doesn't react with barium in there and filed or ground the surfaces clean under the liquid? Then you could quickly pull the sample out of the liquid, shake it off (hopefully a low viscosity liquid), or blow it dry with a jet of argon, and stick it into the sample tube as quickly as possible?
Or stick it in the sample tube wet and blow it dry in the tube with a jet of argon, maybe with a cap on the tube which allows purging the tube with fresh argon from the tank.

This is a total shot in the dark, so don't assume I actually know what I'm talking about.

Dan Vizine - 22-11-2016 at 20:09

Yes, that is accurate.

I can't stress enough how friggin' difficult it is to make tools, solvents and atmosphere dry enough and clean enough. I don't believe I can do it.

No, it's the same logic I used with my Na and K ampoules (another thread). The only way to do it is in a sealed system and as a liquid or a gas.

If you think about it, if anyone could simply use a glovebox and dry supplies, there would already be silver colored metal samples. That suggests that another approach is needed.

aga - 23-11-2016 at 00:39

Very pretty and shiny Ti & Pb samples !

Googling brought up 10.1.1.16.9477.pdf (Decker et al) which is a document that references work by Bridgman (1941, 1942) who apparently worked with elemental Ba in some kind of high-pressure piston apparatus, discovering something called Ba I-II and Ba II-IV transitions.

Tantalisingly the first document just mentions :-

"... oxidation problem encountered with cesium and barium can be minimized through more careful handling procedures".

Other people who worked with Ba are mentioned :-
Kennedy & LaMori, 1962, 1963
Barnett, Bennion & Hall, 1963

Hopefully one of them published something that could help out here.

Woo ! It also mentions Zeto et al, 1968 who used a mix of pentane & iso-pentane with the Ba.

[Edited on 23-11-2016 by aga]

Fleaker - 24-11-2016 at 08:35

Dan, do you need some quartz tubing?

I have a lot of spare 25IDX30 mm OD GE 214 tubing. Bit heavy walled and quite large so you'll need a beastly torch but I can give you a few dozen feet. It won't take the pressure for black P. When I did that I used I think 12 mm tubing with 2 mm walls.

You probably know them, but check out technical glass products up in Painesville, OH. Nice guys that can probably make for you premade ampoules if you want.

Heavy Walter - 25-11-2016 at 12:51

Dan

Quartz tubing up to 25 mm (1 mm wall) can be worked fine with oxygen/propane torch.
But protective glasses must to be special, for quartz.

[Edited on 26-11-2016 by Heavy Walter]

Dan Vizine - 27-11-2016 at 09:11

Quote: Originally posted by Fleaker

Dan, do you need some quartz tubing?

I have a lot of spare 25IDX30 mm OD GE 214 tubing. Bit heavy walled and quite large so you'll need a beastly torch but I can give you a few dozen feet. It won't take the pressure for black P. When I did that I used I think 12 mm tubing with 2 mm walls.

You probably know them, but check out technical glass products up in Painesville, OH. Nice guys that can probably make for you premade ampoules if you want.

Fleaker,

Thank you for your very generous offer, but I suspect that I don't have the capacity to work it.

What I'll have is hydrogen and oxygen and it can be burned in one of two ways. I can use my oxyacetylene torch head or I can use the moderately sized surface-mix torch I bought a couple years back (pictured). The latter is what I'm guessing is better. While I have many hundreds of hours of glassblowing experience, 99.9+% is with borosilicate. I know enough about silica to know that there is precious little overlap.

(Oh, incidentally, in the black P work, did you use the standard Au/Sn method or did you try the more recently found method based on SnI4 alone?)

Heavy Walter,
Thanks for the caution. I'm aware that I have no sodium D lines to contend with. My understanding is that a dark grade of gas welding goggles is totally acceptable. I tentatively plan to use my self-darkening welding mask, since it will also shield from all the radiant heat.

I wanted to avoid C based fuels because of the impurities they supposedly leave in the silica.

[Edited on 27-11-2016 by Dan Vizine]

Heavy Walter - 27-11-2016 at 10:18

Dan
I can see you are already trained in glassblowing.
Great!
Certainly the self-darkening welding mask will be good.
We wait for your setup and results.

Fleaker - 27-11-2016 at 13:18

The mask is the way to go. I like it for melting platinum as well.

Dan, we burn acetylene and oxygen and hydrogen and oxygen out of the same torch. They work interchangeably in my experience and the guy at Praxair who sold me the torches said they can be used for either gas. Also, oxymethane has been OK on small quartz in my experience. A good burner is the most important thing with quartz work.

When I did the black P prep it was using gold additionally. I have not tried the newer method--aside from the nuisance of the gold recovery, what advantages does it confer?

Thanks!

Dan Vizine - 12-12-2016 at 10:17

Quote: Originally posted by Fleaker

When I did the black P prep it was using gold additionally. I have not tried the newer method--aside from the nuisance of the gold recovery, what advantages does it confer?

Thanks!

I think that the main driver was the avoidance of having to pay for Au. Fewer co-products are formed, but my understanding is that separation of the product isn't significantly complicated by these phases, so this isn't very important.

Are your black P syntheses written up here on SM? I'll check, because I'd love to read them.

Dan Vizine - 12-12-2016 at 10:26

Quote: Originally posted by Heavy Walter

We wait for your setup and results.

This will probably be slow, like my last work, but less so, I hope.

Because of funding in universities, we are hella busy from October to December or January. I've only been at home a few days in the past two weeks and I still have a Detroit, Atlanta, and two Florida trips before end of January.

Generally, I can't contribute as much as I used to. We sell more and more gloveboxes all the time, but the people available to handle all of the troubleshooting has gone down. At any given moment I, personally, usually have a half-dozen simultaneous emergencies across the US and Europe. Too busy.

[Edited on 12-12-2016 by Dan Vizine]

Dan Vizine - 30-12-2016 at 07:36

My world was just rocked. I received an e-mail with this picture. Somebody has already achieved the holy grail. Trying to find out the source of this sample.

Polycarbonate Permeation and Adsorption By Oxygen Problem

VIOLiN - 23-2-2017 at 22:27

Quote: Originally posted by Praxichys

Hey, check this out:

http://pubs.acs.org/doi/abs/10.1021/am900206e

Outgassing of Oxygen from Polycarbonate
Sung In Moon , L. Monson and C. W. Extrand *
Entegris, Inc., 3500 Lyman Boulevard, Chaska, Minnesota 55318

It looks like polycarbonate is susceptible to permeation and adsorption by oxygen. Baking while scrubbing may help, or (unfortunately) replacing the PC with stainless steel or glass sheets.

Nice glovebox, by the way.

[Edited on 23-1-2015 by Praxichys]

Hi! I know that this was discussed earlier in the thread, but I just had an idea regarding the permeation of the polycarbonate by oxygen. It might be especially difficult considering that your glovebox is already built, but could the permeation be reduced by taping the polycarbonate with the oxygen impermeable metal (aluminum) tape? It surely wouldn't be as good as the glass or SS, but hopefully it could improve the glovebox's performance. ????

And thank you Mr. Vizine for all of the work you have done into sharing all of your projects. I have really enjoyed all of your work on element samples and thorium production. It has been a joy to read, and I have gotten many ideas! Also, thanks for your ideas on the glovebox. I am currently building a glovebox, and your ideas have helped tremendously!
Thanks!

Dan Vizine - 24-2-2017 at 07:44

Hi VIOLiN,

I'm glad you enjoy my work and thank you for your comments. You are all right, of course, and I had the feeling it may be difficult or futile.

Also, whenever a new glovebox of SS and glass is started, it still takes days to hit 1 ppm moisture. Because, unlike O2 which just floats around waiting to be removed, water has to desorb first. So, everything in the gb was giving off impurities.

And N2 diffuses through your gloves.

The atmosphere was fine for lithium, but that isn't a high bar.

I don't entertain any hopes whatsoever of handling shiny barium in a homemade purged glovebox.

Bezaleel - 25-2-2017 at 10:46

Dan, thanks for posting all your experiences and labour in this thread in the first place! I agree, it is very enjoyable to read, not in the last place because it is well written.

With the oxygen/water removal problem you encountered, is there a reason you have not tried the following:

Water removal. Could you use a heating element and heat the gas inside the glove box to, say, 120C? I guess this will speed up desorption of H2O considerably. I don't know whether the gloves and sealing will withstand this temperature without deteriorating, though.

Dan Vizine - 24-2-2019 at 13:43

I had all but given up on ever being able to prepare good-looking samples of either strontium or barium. Now, perhaps a path has appeared. My previous best attempts in a purged glovebox yielded what you might call mixed results. The sample is clearly metallic, yet there is very little silver coloration, a little bit more golden color, but blue and brown predominate.

I've previously noticed, most recently with europium, that when working with certain soft metals, extruded samples of the metal often seem to be more resistant to immediate attack by the atmosphere than samples that were prepared by scraping, filing or sanding. Maybe this implies that extruded samples present less surface area to the atmosphere than samples prepared by abrasive methods. I've done absolutely no research to back this up and have absolutely no proof that this is the case, but the results deserve further consideration.

I've had scraps and shards of barium metal stored under toluene saturated by argon since I began this thread. They're essentially dark gray in color. I couldn't help but wonder what would happen to them if I simply loaded a pile of it all a into a steel die with a 1-inch diameter steel plunger and a 3/8 inch hole for extrusion drilled into the bottom and exerted a lot of force.

I set up my hydraulic press so that the die sat on a thick steel plate with a three-quarter inch hole drilled in the middle I situated the extrusion hole of the die directly over the hole and underneath the hole was a dried stainless steel cup holding anhydrous toluene. I exerted nearly the full 12 tons of pressure that the hydraulic press was capable of, and when the ram failed to move any farther, I lifted the dye to see a clearly silver colored extrusion of barium metal. I immediately snipped it off the dye from which it was protruding letting it fall back into the original container from which the barium came. The attached picture shows that the metal is clearly silver on the outside. Obviously, the inside of this extrusion is still riddled with oxides and nitrides. However, the suggestion is that if I started with a solid ingot of barium metal, the sample might be pretty good.

It would still need to be ampouled, and you can't take anything for granted with barium, but so far this is better than I had any reason to expect.

Bezaleel - 26-2-2019 at 08:32

Dan, I so much appreciate your persistence in pursuing this difficult goal! Thanks for giving us such a lovely read.

Dan Vizine - 26-2-2019 at 17:50

Hi Bezaleel,
Sorry that I missed your 2/25/17 post. I became dispirited about my chances of success and had no further ideas. Butyl rubber has a service ceiling of 150 degrees, so I could heat the walls. But, with knowledge gained in the last couple of years from a researcher using a gb that we, and he, custom modified for the task of handling barium, I realize that I couldn't succeed in a home-built purged gb. Anyway, the glovebox was converted over for handling thorium a while ago and it will never again be suitable for "regular" tasks.

These barium results seem too good to be true. I wouldn't have accepted this story from someone else unless he had a picture, which I do.

Consider this, the barium was in ~ 15 dark little shards, with aspect ratios of maybe 8 - 10:1. Why don't I see discontinuities along the length? Bands of dark gray...Could it be that this picture is deceptive? Btw, by the next morning, the silvery metal was dark gray.

No sense in pondering these relative unknowables. I purchased a solid 50 g Ba ingot yesterday and when I return home from my current business trip, I'll try some additional experiments.

PS. Please forgive my proofreading shortcomings. Word recognition software has its limits. I caught the first "dye" and changed it to "die" and successfully ignored both following misuses.

Oh, and to follow up on the picture of the silver chip in the ampoule. I bought one. It arrived dark gray. It was returned dark gray. It (the silvery one) was made in a glovebox right after commissioning, they cannot duplicate the results now with the nitrogen that has diffused in since then. This guy is on eBay. He still uses the silver picture of the sample he can't actually deliver.

[Edited on 2/27/2019 by Dan Vizine]

Dan Vizine - 4-3-2019 at 20:45

An appropriately solid ingot of Ba metal was procured.

Dan Vizine - 29-3-2019 at 09:52

After the unexpectedly good results that extrusion seems to have provided, I researched the subject and found that extrusion can be used for purification of metals. It can also serve to distribute impurities uniformly. There is more than one type of extrusion, it depends upon what part moves. When the ram moves it tends to push everything with it and so part of the extrusion will be lessened in impurities and other parts will be increased. For purification purposes, the ideal configuration is a stationary container into which a hollowed out ram is pressed. This is fairly hard to implement while maintaining a highly pure environment around the extruded sample and so I'm going to try the simpler method first.

I've included three pictures below. One simply shows all of the pieces. Another shows details of the supporting plate. It has a lip machined into the hole which supports the expanded lip on the glass tube. A purging tube, for UHP argon, was installed by drilling sideways through the plate. The sharp band in the tubing was achieved by putting a copper wire inside, bending it, and then removing the copper wire. The first material that I'm going to use this with is europium because it's easier than barium. As the long extrusion of europium metal enters the tube, I don't expect that it will break at any point. When the pressing is done it will probably just be hanging from the bottom side of the extrusion hole. This is the less than scientific part. I'll need to quickly lift the extrusion apparatus and use a sharp chisel to separate the extrusion and allow it to fall. A small clean stainless steel spring at the bottom of the glass tube will serve to cushion the impact. Then I'll seal the tube with a rubber stopper and lots of Parafilm until I'm ready to try sectioning and ampouling.

[Edited on 3/29/2019 by Dan Vizine]

Dan Vizine - 23-4-2019 at 06:48

As an example of wasting time, I'd like to offer up my most recent experiences with the extrusion of reactive metals for a quick method of cleanup. My goal is actually two-fold. I'd like to try and repeat my extrusion of what appeared to be a rather silver-colored sample of barium a little while ago. I also need to find a way to purify about a kilo of europium which is partly solid ingot and partly dendritic, unfortunately, more dendritic than solid. I decided to start with the europium because it is considerably less reactive to the atmosphere.
There's no way to clean up the dendrites, short of remelting the metal in a disposable tantalum crucible under inert gas to separate the clean metal from the air-reacted metal. I don't currently possess the requisite equipment.

I had a length of one and three-quarter inch outside diameter steel rod with a 1-inch hole down the center. The hole was not done by drilling or on a lathe, probably more by the process known as piercing. As such, the hole is not 100% perfectly cylindrical and it's also made of soft steel. I weld a steel plate onto the bottom and drill a hole the size of the extrusion that I desire. The plunger is also soft steel and I made the mistake of giving it perfectly squared off edges. There should have been a very small conical section ideally. There was also some play in the fit, I'd estimate it to be a few tenths of a millimeter, perhaps as much as 0.5 mm.

As I attempted to extrude europium from a 1 inch diameter die through a 3/8 inch diameter hole (that calls for much lateral flow of metal and that is pressure intensive, a larger extrusion is much easier) the high forces required caused europium to flow up the side of the die which had the poorest fit with the plunger. With every millimeter of forward movement, I was causing more sideways pressure to be exerted on the plunger. The plunger, having the aforementioned squared off edges, saw fit to dig into the side wall of the die and within a few more millimeters of forward motion it had caused gouging, galling and had seized-up. The plunger wasn't going anywhere even with a full 12 tons of force on it.

I did the only thing that I could do, I removed the unit from the press, cut off the small extruded Eu nub, located a 3/8 inch diameter hardened steel rod about 2 inches long and pushed it into the extrusion hole using the press. Eventually, I got the plunger out and salvaged the europium with minimal loss of material.

This all leads me to precisely where I found myself when I was pressing thorium powder into metal disks prior to sintering. I need a die and plunger set with a precise fit, preferably entirely made of hardened steel, and also one that can be adapted for extrusion rather than just pressing pellets. A quick search of eBay revealed that not only couldn't I find exactly what I wanted, but things that were reasonably close and might be adapted were quite expensive, which should have been no surprise. The little tiny 10 mm hardened steel die that I bought for processing thorium was $40 to $50 dollars. The price of such units goes up very quickly as the size does.

Now I have two choices. I have two lengths of very nearly 1.00-inch outer diameter hardened steel rods, each about a foot long. An abrasive cut off wheel would allow me to take a section of the appropriate length. I also have steel blocks that were precision drilled with 1.00-inch holes. I suppose my only practical/affordable solution at this point is to make my own plunger and then try it with these precision drilled blocks. I really hate the idea of welding steel plates to these blocks and so perhaps I will try simply clamping a metal plate to the bottom side.

With respect to Maroboduus' suggestion, on the face, it's attractive, in practice it doesn't work very well at all.