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m1tanker78
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Refining Na/K From Various Processes
I created this thread to reduce cluttering in the potassium and t-alcohol threads and to (hopefully) generate some productive discussion about
refining/coalescing the alkali metals (mainly Na and K), irrespective of the process used to produce them.
For example, if anyone has a creative process or idea for separating metal-thermic Na from the slag, let's hear it! We've been discussing using
blended brake fluid for Na. I can't vouch for 'thermic Na but can vouch for usefulness with electro-chemical Na. Having at least a couple of 'thermic
Na testers would be good. A few members here are now making potassium as well so thoughts concerning K are encouraged, too.
NurdRage is going to produce a video which outlines such procedures so improvements to existing methods or new methods would be appreciated.
Tank
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NurdRage
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If the chunks are reasonably large, then physically pressing them together with a pestle and mortar (or a pair of pliers as in my case) until they
physically bonded and then heating them in inert solvent until they melt causes them to pull together into spheres with the impurities on the surface.
It's crude, but it works.
The process also works on smaller bits if they are clean. I turned sodium and potassium sand into single spheres this way.
-----> It goes without saying that everything must be bone dry before doing this work. 
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m1tanker78
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Nurd, I assume you use the magnesiothermic reaction to yield Na? If so, what do you do with all the little bits that get stuck in the slag? Have you
tried the mineral oil/brake fluid blend to raise the Na bits to the surface?
Tank
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querjek
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Could you put a mass in a crucible and then heat it beyond 100C? That would (presumably) drive off water and anything below its boiling point plus
burn (or at least start to) residual organics in the material.
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m1tanker78
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querjek, what mass?
[Edited on 5-3-2011 by m1tanker78]
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NurdRage
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Quote: Originally posted by m1tanker78  | Nurd, I assume you use the magnesiothermic reaction to yield Na? If so, what do you do with all the little bits that get stuck in the slag? Have you
tried the mineral oil/brake fluid blend to raise the Na bits to the surface?
Tank |
yeah... but the process is very messy since a lot of the slag also rises. 
I'm still working on that one.
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m1tanker78
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Ok, no wonder. I was under the false impression that this worked and was a done deal for the most part (for 'thermic Na).
It's odd because nascent sodium is the least dense component of all of the reaction products and unreacted components. I can see how the small oxide
particles could easily be stirred up by the currents. Have you tried adding the BF to the warm oil drop by drop? Also, what type of BF are you using?
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Twospoons
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copied from the 'make potassium ' thread:
| Quote: Originally posted by watson.fawkes | | Quote: Originally posted by Twospoons | Must be a good one then! [...] I suggested a NST as its a very easy way to get to 20kV. And no more dangerous than playing with blobs of molten K 
Multipliers are good too- just watch out for the stored charge |
It's not apparent to me that it's such a good
idea. Putting a 7 kV potential inside your hand is not something that the HV crowd does in any kind of regular basis. You have to plan for failure,
particularly in this case. It's not like glass never breaks in the lab. I'd say that this tool is significantly more dangerous, at least at first
blush, than molten K.
As far as supplies, the difference between a multiplier and a neon sign transformer is that a multiplier has a bit of stored charge, which will
dissipate, and the NST has no stored charge, and will keep pumping current indefinitely. You absolutely need an inherently current-limiting supply for
this tool to be anywhere near safe. Using an HV transformer pretty much negates that from the start.
Upon further consideration, I'd heartily suggest putting the entire multiplier in the wand on the far side of the handle, so that only the supply
voltage of 600 V - 1 kV or so is in the handle. This complicates construction, of course, but seem like a much better idea than running flexible HV
cables and having the wand just be passive conductors. At 20 kV potential, it's not an insignificant problem just to source adequate insulation for
your wire. In order to avoid corona and arcing inside such a relatively small space, it's necessary to use some kind of potting. Oil or paraffin wax
would both work, it seems. You're still going to end up with a thick handle.
Perhaps a much better option is to make this not-a-hand-tool at all. The advantage of a hand tool is that you can wave it around and provide
mechanical motion easily. With a fixed tip, you have to move the K, rather than vice-versa, which leads to a whole host of other problems.
The upshot is that this should under no circumstances be anyone's first HV project. There's nothing here which is simultaneously safe and easy.
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I never suggested a hand tool for HV. My thought was always based around fixed electrodes.
Neon sign trannies are inherently current limited, usually to a few mA. Still nasty if you get hit by one though.
Automotive ignition leads would make good HV leads - they're resistive, thick, and heat resistant. A water resistor could be used for additional
safety.
A multiplier has a bit of stored charge, sure, but it also has a string of diodes directly connected to the driving source. If that source is capable
of 10's or 100's of mA at a few hundred volts, then the multiplier is every bit as dangerous as a NST.
Both solutions require care, and a high value ballast resistor of a few mega ohms.
Helicopter: "helico" -> spiral, "pter" -> with wings
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m1tanker78
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Twospoons, I've been lurking the potassium thread, hoping someone would try this, hehe. I don't fully understand the theories behind this so it leaves
me with a couple of questions. First off, I realize that air is a crappy dielectric compared to oil but why couldn't the potential be applied from
outside the [glass] vessel? Or could it? Maybe in a partial vacuum?
Second, if K becomes ionized by said electrical potential then wouldn't it release some of the energy in the form of photons when the electrons
normalize? I'm thinking lasers here but I know they're 2 very different elemental animals.
What about [ultra]sonic agitation or even R.F.?? Ultrasonic cavitations are powerful little buggers but I don't know how a HC would behave when
irradiated.
BTW Twospoons, I love your sig. If only it were that easy! 
Tanker
[Edited on 5-4-2011 by m1tanker78]
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NurdRage
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| Quote: Originally posted by m1tanker78 |
Ok, no wonder. I was under the false impression that this worked and was a done deal for the most part (for 'thermic Na).
It's odd because nascent sodium is the least dense component of all of the reaction products and unreacted components. I can see how the small oxide
particles could easily be stirred up by the currents. Have you tried adding the BF to the warm oil drop by drop? Also, what type of BF are you using?
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The thermochemical sodium reaction isn't pure, in that it doesn't make only sodium and only magnesium oxides, it also makes hydrides. those hydrides
react with the alcohol functional groups in the brake fluid and produce hydrogen. The hydrogen is still clinging to the particles and thus causes them
to rise.
i'm using Dot 3 fluid. Polyethylene glycol.
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blogfast25
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Regarding Twospoons’ and Watson’s idea of electrical field coalescence, although it might very well be very effective if executed properly, I for
one won’t be trying this because of lack of experience/equipment in the HV realm. Shame because it sounds very promising. Electrostatic collection
of dust particles is in industrial use in some ore refining businesses.
Another avenue that could be explored may be vibrations or ultrasound to try and smash small globules into each other.
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m1tanker78
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I've done some more testing with a DOT 3 blend. I extracted some sodium spherelets (approx 3 or 4 grams worth) from some rubble in the usual way of
adding BF to hot oil a little at a time and then ladling off the floating Na. I put them in a container with mineral oil for further processing...
BF cripples the coalescence of sodium to the point of making it 'spontaneous'. I
had to do a total of 5 cycles of (heat...cool...decant...more oil) before I got everything to mate up. Coalescence became progressively easier with
each 'wash'. This obviously turns further processing of the rubble into a headache. Then, there's the question of whether such sodium nuggets will
contaminate the storage oil. Still, there has to be a way to get the best of both worlds. Until then, I'll probably go back to chucking the
post-process rubble in the garbage.
I guess I can't have my cake and eat it, too. Back to the drawing board!
EDIT: On the other hand, the nugget is extremely clean, inside and out. I'll bet I can suspend the small beads in hot oil with a fine
mesh strainer to coalesce (hopefully) then move to a coarser mesh for final cleaning before storing. This would solve the problem of the nuggets
solidifying on top of the muck, inevitably adhering to some of it.
Tanker
[Edited on 5-6-2011 by m1tanker78]
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Twospoons
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I wondered whether ultrasonics would work, but I suspect the power level would be very important, otherwise you might get the reverse of the intended
result - a sea of tiny particles!
Helicopter: "helico" -> spiral, "pter" -> with wings
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watson.fawkes
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| Quote: Originally posted by Twospoons | | I wondered whether ultrasonics would work, but I suspect the power level would be very important, otherwise you might get the reverse of the intended
result - a sea of tiny particles! |
As far as mechanical means go, it's seemed to me that a centrifuge would
be worth looking. I'm thinking about the sort of centrifuge used in lost wax casting, rather than the kind used in cell biology. For the improvised
lab version, consider a bicycle wheel mounted horizontally with a pair of hinged flask holders. Crank the wheel up, and the flasks tilt up as the
speed increases. Let it spin down, the flasks tilt down. Bonus points for putting in a differential, cranks arms, and foot pedals.
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m1tanker78
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| Quote: Originally posted by watson.fawkes | | Quote: Originally posted by Twospoons | | I wondered whether ultrasonics would work, but I suspect the power level would be very important, otherwise you might get the reverse of the intended
result - a sea of tiny particles! |
As far as mechanical means go, it's seemed to me that a centrifuge would
be worth looking. I'm thinking about the sort of centrifuge used in lost wax casting, rather than the kind used in cell biology. For the improvised
lab version, consider a bicycle wheel mounted horizontally with a pair of hinged flask holders. Crank the wheel up, and the flasks tilt up as the
speed increases. Let it spin down, the flasks tilt down. Bonus points for putting in a differential, cranks arms, and foot pedals.
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And extra bonus points for incorporating heat!
My original scheme was to create a standing wave in the oil bath. I doubt ultrasonics would be required - probably just a speaker with a push rod
instead of the cone and an amplified adjustable frequency generator. The idea is that the small sodium or K beads would align themselves in the trough
to promote intimate contact. Some of the lighter slag would be stirred up as well but as long as the metal beads are floating, it shouldn't present
too much of a problem.
Heck, this could probably be tried with a thin-walled metal container and a weed eater. An electric weedie would require a variac for 'frequency'
control. The trimmer string would create a periodic percussive wave and so on... The amplitude could even be adjusted to some degree.
Tank
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blogfast25
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| Quote: Originally posted by watson.fawkes | | As far as mechanical means go, it's seemed to me that a centrifuge would be worth looking. I'm thinking about the sort of centrifuge used in lost wax
casting, rather than the kind used in cell biology. For the improvised lab version, consider a bicycle wheel mounted horizontally with a pair of
hinged flask holders. Crank the wheel up, and the flasks tilt up as the speed increases. Let it spin down, the flasks tilt down. Bonus points for
putting in a differential, cranks arms, and foot pedals. |
Yep, should have thought of that myself: turn that Na or K into mercury, simply put. Not so easy to realise for the home guy but not unfeasible
either. Although reaching 13 g (referring to Hg) may not be so easy: about 107 RPM for a 1 m radius centrifuge
Tanker’s idea would be worth exploring, too, I think… anything to make the globules exert force on each other…
Mechanical compacting may still be the easiest solution...
[Edited on 10-5-2011 by blogfast25]
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m1tanker78
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Ok, I just got done experimenting some more with coalescing Na that's been treated with brake fluid. Along the same lines, I also tested my strainer
method I proposed somewhere else.
I believe I posted my Na in BF/MO blend video clip in the t-alcohol thread but rather than explain it again I'll just repost here...
<iframe sandbox width="480" height="390" src="http://www.youtube.com/embed/mw-lhQiO2WY?rel=0" frameborder="0" allowfullscreen></iframe>
What I did was to collect the sodium bits in a small aluminum mesh strainer - essentially a large sewing thimble with a coarser mesh. This worked
beautifully since the Na bits circulate up, over, then back down. Once I had most of the bits 'trapped', I began trying to merge them...
At this point, I had a lot of flexibility in subjecting the Na to different temperatures, depth in the blend, most importantly, I was able to
shake the strainer to make the sodium pieces bump into each other forcefully. After shaking both in the blend and in open air, only a few of
them merged into one larger blob. The pieces had enough intimate contact to make them deform each other. Still, no significant coalescence!
I grew a little frustrated and held the strainer directly in the torch flame for a second or two at a time then dipped back in the blend. What ensued
was complete merging of all the sodium almost instantly (in the flame). Na's surface tension is sufficiently high to keep the molten metal from
falling though the (aluminum) strainer - even when suspended in the air.
Impressions I'm left with after this experiment:
1). The garage-attainable sonic/ultrasonic/g-forces talked about above will probably prove to be useless for coalescing post-hydroxyl(break
fluid) NA.
2). This seems to support my theory about a stubborn film on Na/K after treatment with BF, possibly any -OH solvent.
3.) Should work fine for K. Metal-thermic Na would need to be tested but I don't see why it wouldn't work well.
Here's the sodium nugget. A soak in RT mineral oil will dissolve the golden-brown gunk and passivate it before transferring to storage...
Just below MP:
Mineral oil soak to dissolve organic residue and pre-passivate. Bruising can be observed from resting against the strainer...
Tank
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blogfast25
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That’s a very interesting result, Tank.
Your ‘film explanation’ still doesn’t really convince me though: the globules in the video are shiny like new.
You are however once again tickling the Dragon’s tail: do this once too often and you’ll have a sodium fire, not coalescence. 
I can’t pinpoint what’s causing this and you should at least replicate your experiment once but my gut feeling is that the temperature
differential between the Na that passed through the flame (Na has a very high heat conductivity, so it heats up quickly) and the solvent may be the
cause here, although right now I cannot see why.
I cannot repeat this with potassium (too dangerous, especially with larger quantities) but could try and replicate this with a strainer, a bath of
real hot kerosene and a bath of much cooler kerosene…
Very nice pix, BTW... the top one is almost SciFi!
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watson.fawkes
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| Quote: Originally posted by m1tanker78 | | I grew a little frustrated and held the strainer directly in the torch flame for a second or two at a time then dipped back in the blend. What ensued
was complete merging of all the sodium almost instantly (in the flame). Na's surface tension is sufficiently high to keep the molten metal from
falling though the (aluminum) strainer - even when suspended in the air. |
It seems to me that the significant
difference is coalescence in gas rather than liquid. With molten Na in a liquid medium, there's a thin film of the medium between any two globules.
That film has to break somewhere for the globules to touch, much less merge. If you push on the film from both side, you'll eventually pinch a hole in
it. In the present case, there's no such film, since there's insufficient medium to keep one intact. Gas doesn't form such films, so there's nothing
to break.
For safety, the main thing is that the gas not be oxidizing. Reducing or inert gases should be fine. Neutral gas might be, but it's at the margin of
safety, and I wouldn't recommend it. Anybody who's done much blacksmithing or other hot work with metal knows how to create a reducing flame. For
those who don't, a charcoal fire with a controlled draft (air intake) is mostly N2, CO2, and CO and should work just fine for this purpose. A tiny
furnace with a variable speed fan should generate a perfectly good gas flow for this purpose. Only use with adequate ventilation (outside or hood)
because of the CO.
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m1tanker78
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Thanks for the kind words, BlogFast! I honestly have no explanation for what the film could be. I just know that something makes coalescence very
difficult after having been in the brake fluid or a blend. Speaking of tickling the dragon's tail, I'm not so confident about hot kerosene! Why not
use mineral oil or even a non-synthetic engine oil if you try the strainer method? I believe you'll probably also run into the same trouble so use a
few 1 and 2mm sized K beads. If they refuse to merge, pass the strainer over a reducing flame and dunk it in the oil if the K catches fire. Having
some dry NaCl and dry sand handy is a good idea, just in case...
Watson, the sodium pieces slouch when they're removed from the oil. They should instantly merge but it's never that easy after treating with
brake fluid. There's something (polar nature of BF??) that seems to keep them from touching, even when a large sodium glob is sitting on top of
smaller ones.
I left out the safety section but I'm prepared to deal with a much larger sodium fire. Anybody possessing or handling reactive metals should be armed
with knowledge and firefighting materials and techniques. Don't get caught up in a "shit, the sodium's on fire, what do I do?" situation!
Tank
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blogfast25
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| Quote: Originally posted by watson.fawkes | In the present case, there's no such film, since there's insufficient medium to keep one intact. Gas doesn't form such films, so there's nothing to
break.
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When you lift the alkali metal globules out of the fluid (whichever that is) they don’t drip dry completely and the solvent doesn’t evaporate. So
there’s still a solvent film coating and separating them. Good thing too: even sodium would otherwise catch fire at these temperatures! It’s the
solvent film that protects the metal from air oxygen…
Also, if the absence of fluid was the cause for the mystery ‘sudden’ coalescence the latter would occur after lifting them out of the fluid, and
no additional heating would be needed either.
The one thing that also changes when you lift the molten metal out of the liquid is that all of a sudden their weightlessness is suspended and they
take on their ‘normal’ weight (in air). Gravity now tends to force them together somewhat. Tank is right that the ‘slouching’ could promote
the conditions in which the remaining fluid film gets pierced, yet he didn’t observe that. Is it possible that some piercing did occur and that on
subsequent re-submerging the balls then fuse smoothly together?
Tanker should perhaps repeat his experiment, perhaps with heating and without heating. Perhaps with ‘jiggling’ the balls while they’re briefly
out of the fluid ?
| Quote: Originally posted by m1tanker78 | Speaking of tickling the dragon's tail, I'm not so confident about hot kerosene! Why not use mineral oil or even a non-synthetic engine oil if you try
the strainer method?
[...]
Watson, the sodium pieces slouch when they're removed from the oil. They should instantly merge but it's never that easy after treating with
brake fluid. There's something (polar nature of BF??) that seems to keep them from touching, even when a large sodium glob is sitting on top of
smaller ones.
Tank |
Kerosene IS a mineral oil, almost exclusively > C10 alkanes, inert to Na or K. That’s why it’s such a useful solvent also
DURING reaction. It’s routinely used to store Na or K under. It's one of the safest solutions to that problem. But it’s flammable of course, so in
case of a hot breakage you had better be prepared!
By contrast, unadulterated brake fluid shows some reactivity to the metals. The surface hydrogen HAS to be an impediment to coalescence, IMHO…
I think we’ll get there in the end.
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m1tanker78
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BlogFast, no questioning the usefulness of kerosene for storage or reaction medium. I'm concerned about the flammability, though. I don't see how the
strainer method can be well-implemented in a closed flask. How would you manipulate the strainer?
| Quote: | | Tanker should perhaps repeat his experiment, perhaps with heating and without heating. Perhaps with ‘jiggling’ the balls while they’re briefly
out of the fluid ? |
Not sure what you mean by 'without heating'. I assume you meant directly in the flame. The oil was plenty hot! As far as jiggling, I did this for a
good 10 minutes at 3 different temperatures, both in the blend and in air at each temperature. I damned near used the strainer-ed sodium to play the
maracas (wearing my PPE 'armor').
I did another quick experiment (honestly can't call it a 'repeat' because I changed some variables). This time, I manually picked several 1 or 2mm-ish
sodium beads out of a MOBF blend and placed them in the strainer. The oil medium I used was a [used] MOBFSA blend -- (Mineral Oil + (Brake Fluid +
Sulfuric Acid)). I ran out of MO and was too late to run to the store so this is what I had to work with. I haven't had time to further test MOBFSA so
that's still up in the air but in the works.
This time 'round, as soon as the sodium bits passed MP, they mostly merged while suspended in air with little more than 'jiggling'. Still a little
more difficulty than what I'm used to but MUCH improved from the last attempt. I uploaded a video clip to demonstrate how I did it:
My apologies for the experiment leaving the FOV at times. I was paying more attention to the task than to the camera angle. The oil container
has a base that makes it tip-proof in the vice...
<iframe sandbox width="640" height="510" src="http://www.youtube.com/embed/tg6zine1CUQ?rel=0" frameborder="0" allowfullscreen></iframe>
The resulting sodium bead:
Needless to say, damned clean sodium for a 'one-pot' separation, collection, cleaning and coalescing. Strainer method needs a little work but off to a
good start, IMO. Strainer method Na on the right, non strainer Na on the left...
+++++++++++++++++++
NurdRage, if you're still checking in, do you think this could be useful for thermo-Na?
Tank
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blogfast25
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Quite convincing, Tank. No passing through a flame this time, just juggling when they’re out of the frier. I WILL try this at the earliest possible
convenience with K. Clearly jiggling outside of the frier at normal weight and without the viscous resistance of the fluid, allows to create more
effective collisions between the metal globules. That’s is simply what’s happening, IMHO and it’s potentially very effective…
Don’t have too many illusions about the flammability of a brake fluid/engine oil blend: despite the oxygen content of the polyglycol ether esters,
brake fluid must be quite combustible. Not to mention the HC of the engine oil…
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blogfast25
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My coalescing experiment with isopropyl myristate didn’t yield much. The product, extracted from Dentyl pH (carefully washed and dried), was
reactive to the potassium from about 50 C onwards but I’m sure it wasn’t water that was reacting. I believe this is due to residual ‘stuff’ in
the ester because it reeked of menthol and other substances present in the Dentyl pH. I’ll try another longer chain aliphatic ester but one that’s
clean.
I haven’t had time to test the last results of Tank yet, possibly tomorrow…
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m1tanker78
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BlogFast, what prompted you to try IPM in the first place? Just curious since the reported density is nearly identical to that of inert HC's like
kerosene. Was it the slight polarity??
I think surfactants have been brought up before but didn't evolve into any practical experiments. I've had my eye on organosulfate surfactants for a
little bit now. More curiosity/novelty than practical usage with alkali metals. Na-Dodecyl Sulfate comes to mind...
Tank
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