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IrC
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I agree with that. I have several ingots left and I have no idea what an assay would show. Lots of green, yellow, and white powder when I unwrap one
mostly because I am too lazy to can them in oil and bought them around 11 years ago. I just have them wrapped in plastic. Seem to be very high in Ce
and La percentage, would be nice to have received an assay sheet with them but the price was too good to pass on to let that get in the way of the
purchase. I just bought them with the thought in mind of separation, until I studied the subject enough to realize that would be hard. Not a problem
if they are low in Nd though as I have a 2.25 pound ingot of Nd in a paint can of mineral oil. Keeps well even after a decade since I only see a
slight swirl of color in the oil from the trace of powdered oxide.
"Science is the belief in the ignorance of the experts" Richard Feynman
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Dan Vizine
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BF: I expect to be a customer.
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elementcollector1
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Kind of a cross-thread question, but here is as relevant as the other threads. Is there some type of valve that could be used during vacuum (e.g.
purge the reaction container, and close the valve so it stays at low pressure, and then open it again when the reaction is finished)?
Elements Collected:52/87
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blogfast25
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Quote: Originally posted by elementcollector1  | | Is there some type of valve that could be used during vacuum (e.g. purge the reaction container, and close the valve so it stays at low pressure, and
then open it again when the reaction is finished)? |
If you have reaction going on with production of volatiles, your vacuum will always suffer, hence the need to keep pumping.
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elementcollector1
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| Quote: Originally posted by blogfast25 |
If you have reaction going on with production of volatiles, your vacuum will always suffer, hence the need to keep pumping. |
If that is the case, how do I prevent volatile products from entering the vacuum system (and presumably destroying it from the inside out)?
Elements Collected:52/87
Latest Acquired: Cl
Next in Line: Nd
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Chemosynthesis
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I would use at least two vacuum traps in that case. You can try to run with dry ice to condense fumes. I've seen aqueous ethylene glycol used as the
liquid in these types of traps due to the solvent effects on fumes, and the formation of a cold bath. Additionally, it's a high boiling point,
non-volatile solvent, so less of it would get into your pump than acetone, EtOH, i-PrOH, etc.
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blogfast25
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Depends how volatile they are. In Dan's preparation of Cs the condenser he uses appears to be enough to protect the vacuum pump, if I recall well.
Volatiles needn't be detrimental to the pump either: it depends what they are. If you really need to eliminate them, cold traps are probably best, as
the previous poster indicated.
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elementcollector1
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Sounds good. What I was hoping to do was build an "all-purpose" steel reactor that can either be connected to a condenser for volatile products (Cs,
etc.), or simply be capped off for sublimation or non-volatile products (As; Nd, La, Ce, etc.). This would have had a vacuum takeoff *before* the
condenser outlet.
Elements Collected:52/87
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Next in Line: Nd
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blogfast25
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Unless I understand your idea wrongly, that would mean sucking Cs or volatiles into the pump. The condenser should be between the reactor and the
pump. The pump needs to pump constantly to maintain the vacuum required.
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elementcollector1
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Yeah... But then how would sublimation under vacuum work? No matter what you did (short of putting some insanely long length of tubing to the vacuum
takeoff, so that everything condenses before it reaches the pump), you would end up having a direct line from the gaseous products to the pump.
Perhaps I should just use the distillation setup for those reactions as well...
Elements Collected:52/87
Latest Acquired: Cl
Next in Line: Nd
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Chemosynthesis
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| Quote: Originally posted by elementcollector1 | Yeah... But then how would sublimation under vacuum work? No matter what you did (short of putting some insanely long length of tubing to the vacuum
takeoff, so that everything condenses before it reaches the pump), you would end up having a direct line from the gaseous products to the pump.
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You usually use a cold finger. That, coupled with a vacuum trap or two should essentially prevent volatiles from entering the pump in sufficient
concentrations per time to cause issue.
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elementcollector1
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Don't have a cold finger on me, but I do, in fact, have a vacuum trap handy. Another thought - how does one link the vacuum pump and the system
without flexible tubing?
Back on topic, I guess I'll suck it up and get some nitric acid.
Elements Collected:52/87
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blogfast25
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Trust me, condensing something with such a high ambient BP is not a problem under vacuum: the condenser surface temperature is still much lower than
the near vacuum BP.
[Edited on 22-4-2014 by blogfast25]
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Brain&Force
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I'm still wondering if fluorescence can be used in the solid or liquid states to track the presence of certain lanthanides in mixtures. In the terbium
thread, I've mentioned that ferric ions quench the fluorescence of terbium (though this appears to be due to conflicting absorption and emission
bands).
Does anyone know (or at least have any ideas) as to why dissolved terbium compounds do not fluoresce in solution?
| Quote: Originally posted by Dan Vizine | The positive effects of scandium on aluminum alloys were discovered in the 1970s, and its use in such alloys remains its only major application.--
Wiki
You could probably expect to see this in applications where cost is secondary, military or not.--Me
A few % Sc in Al is all that is needed. You get a gun light as aluminum but strong as steel. As I noted before, verry expensive. These guns set
records*. In bicycles they allowed the ultimate in weight reduction. I guess it maybe didn't catch on in bikes as I never hear about it, usually Ti/Al
is the thing I believe. Probably too pricey.
*not accuracy
[Edited on 15-4-2014 by Dan Vizine] |
The problem with these guns is that they have WAY too much recoil - I've read this in several places.
At the end of the day, simulating atoms doesn't beat working with the real things...
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Chemosynthesis
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The earlier ones actually cracked frames due to the recoil sheer forces and metallurgical missteps. I'm of the opinion this decreased sales initially.
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Dan Vizine
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| Quote: Originally posted by blogfast25 |
Depends how volatile they are. In Dan's preparation of Cs the condenser he uses appears to be enough to protect the vacuum pump, if I recall well.
Volatiles needn't be detrimental to the pump either: it depends what they are. If you really need to eliminate them, cold traps are probably best, as
the previous poster indicated. |
In my case, with Cs, the volatiles were primarily non-corrosive gasses and no trap was needed. This represents one of the most vexing things for a
basement lab to do...to simply protect your rotary vacuum pump from nasty volatiles. And this is because of only one reason, you need a supply of dry
ice or LN2. For most of us this is inconvenient (I have to drive into South Buffalo, over 12 or 13 miles, to get dry ice) or impossible.
One previous post confused me...about getting acetone or 2-PrOH vapors into the pump because of cold traps. The dry ice/ acetone surrounds the outside
of the trap. None of it gets into the pump. I favor an alcohol for this, isopropanol or ethanol.
[Edited on 27-4-2014 by Dan Vizine]
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Dan Vizine
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| Quote: Originally posted by elementcollector1 | Don't have a cold finger on me, but I do, in fact, have a vacuum trap handy. Another thought - how does one link the vacuum pump and the system
without flexible tubing?
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Copper lines are good if you watch what you pump through them. You still need a small length of flexible tubing to transition to the
glassware. I have no clue where you are, but Home Depot, Lowe's and most hardware stores carry rubber and plastic tubing. The vinyl tubing is cheaper,
less durable and can be used with thinner walls than the rubber tubing requires. It is less collapsible.
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Chemosynthesis
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| Quote: Originally posted by Dan Vizine |
One previous post confused me...about getting acetone or 2-PrOH vapors into the pump because of cold traps. The dry ice/ acetone surrounds the outside
of the trap. None of it gets into the pump. I favor an alcohol for this, isopropanol or ethanol.
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I was thinking of dry vacuum pumps. I'm not very familiar with them, but I am under the impression they are open to solvent fumes, potentially even
from traps or open solvent containers outside of a fume hood, since they lack an oil seal or gas ballast, but I could be mistaken.
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Dan Vizine
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| Quote: Originally posted by Chemosynthesis | | Quote: Originally posted by Dan Vizine |
One previous post confused me...about getting acetone or 2-PrOH vapors into the pump because of cold traps. The dry ice/ acetone surrounds the outside
of the trap. None of it gets into the pump. I favor an alcohol for this, isopropanol or ethanol.
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I was thinking of dry vacuum pumps. I'm not very familiar with them, but I am under the impression they are open to solvent fumes, potentially even
from traps or open solvent containers outside of a fume hood, since they lack an oil seal or gas ballast, but I could be mistaken.
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Do you mean the modern laboratory style? Those pumps (often scroll pumps) will handle nasty stuff as they have Teflon parts in the vacuum train. They
are great for many things, although expensive. They don't achieve comparable ultimate vacuums vs. oil filled pumps, but that wasn't what they were
designed for.
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Chemosynthesis
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| Quote: Originally posted by Dan Vizine |
Do you mean the modern laboratory style? Those pumps (often scroll pumps) will handle nasty stuff as they have Teflon parts in the vacuum train. They
are great for many things, although expensive. They don't achieve comparable ultimate vacuums vs. oil filled pumps, but that wasn't what they were
designed for. |
Interesting. I'm actually not very sure what I mean, now that I think of it. Is dry vacuum synonymous with the diaphragm pumps I see with rotovaps?
http://www.sigmaaldrich.com/analytical-chromatography/analyt...
Most vacuum pumps I've ever had to deal with were conceptual black boxes to me. They either had some kind of port in the hood, or a plastic encased
switch you press. Whenever I asked people about them, I got the run-around, or strange stories about pump explosions. I know I've had to use at least
two types of vacuum pump: one was recirculating, and I assume was a peristaltic pump in a grey enclosed tub. The other is standardized through the lab
and attached to every rotovap (all Buchi, that I've seen), and then the mysterious high vac came from a barb in one of the hoods.
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IrC
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I know that Iron atoms in extremely small amounts totally destroy the glow from all the Lanthanide doped glow powders I ever made. In the literature
they discuss how sensitive these compounds are to being 'poisoned' by Fe. The nitrate (or sometimes Chloride depending upon formula) is usually the
best form as a dopant and being very expensive and difficult to find I collected nearly all Lanthanide's. Some in large chunks such as La 1.5 lbs and
Nd 2 lbs (both in their own paint can under oil). I figured making the nitrate was cheaper. Many of them are hard to work with so I would take a block
out and hacksaw off a piece. I very carefully cleaned both pieces with solvents to eliminate any possible bits of Fe from the saw blade contaminating
my metals. For over a year every formula I tried failed, Quick fade of glow after uV removed. Studying patents for months I came across many Fe poison
references in various glow powder patents. So I dumped the nitrates I made and very thoroughly cleaned my metals for quite some time. I resorted to
using a cut off wheel (Carbides), then cleaning the piece before making a nitrate. My next glow powder kicked ass. Every step exactly the same for the
particular formula I tried which failed in every previous attempt for nearly 2 years. This time I could get about 12 hours of glow from Lanthanide
doped Strontium Aluminates, 5 or 6 hours from similar Aluminates with Ca replacing Sr but a hell of a lot brighter. My point being I learned that even
a speck of Fe I could not even see ended up destroying the glow effect from the finished powder. Fe atoms create traps in the lattice structure and
these type glow powders are incredibly sensitive to Fe. So sensitive I wonder if one could use this effect as a way to detect Iron when the quantity
was only a small number of atoms.
"Science is the belief in the ignorance of the experts" Richard Feynman
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Töilet Plünger
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Holy expletive...
This may be the reason why NurdRage's glow powder may have had many dead flakes.
Where did you find the Fe quenching references?
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IrC
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| Quote: Originally posted by Töilet Plünger | Holy expletive...
This may be the reason why NurdRage's glow powder may have had many dead flakes.
Where did you find the Fe quenching references? |
Searching thousands of patents over a decade. A recurring theme. Also mentioned in much literature on the subject.
I should mention if some of his material glows for hours brightly unlikely Fe poison is the reason for the dead flakes. Far more likely uneven mixing
and/or problems with reduction. Very likely if he kilned his powders without a tightly controlled atmosphere inside the kiln.
"Science is the belief in the ignorance of the experts" Richard Feynman
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Brain&Force
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He used microwave synthesis, not a kiln. The reagents were purified by recrystallization, but the aluminum nitrate nonahydrate appeared to have some
FeCl3 in it.
At the end of the day, simulating atoms doesn't beat working with the real things...
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Bezaleel
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That's highly interesting, IrC. I wonder whether you tried to detect any iron in your nitrates? If so, by what methods?
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