Melgar
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Surprisingly cheap thorium
It seems China has far more thorium than it knows what to do with, as a byproduct of rare-earth metal mining. Thorium nitrate goes for something like
$1 a kilogram on Alibaba, but they can't export it to most countries because of international nuclear regulations. The only exceptions seem to be as
components of lantern mantles and tungsten welding electrodes. But because thorium is so much cheaper than tungsten in China, they're apparently
pushing the limits on how much thorium they're putting in welding electrodes. I've seen quite a few discussion here on getting thorium from 2%
thoriated electrodes, but now 4% ones are popping up for sale too. Search for "tungsten wt40" on ebay, and see what comes up. I got ten 1/8" x 7"
electrodes for $30 or so, which comes out to about 12-15 grams of thorium metal, and somewhat more thorium oxide, which is what you'll get when you
dissolve away the tungsten.
The fastest way to dissolve them is to set up an electrolytic cell with the tungsten rods getting the positive charge. Use potassium or sodium
hydroxide as the electrolyte. Using nitrite salts will speed up the reaction, at the very real risk of burning out your power supply. I burned out a
corsair 750-watt computer power supply doing this, and I didn't even think that was possible. (Computer power supplies are supposed to just turn off
if they're overloaded) I got a 5v, 60w power supply on Amazon for about $12 and put an inductor in series with the cell to limit the current. So
far, this has worked pretty well.
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careysub
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Actually you should have 9.5 g of elemental thorium there, of about $3.50/g. Which is quite good.
Have you tried the hydrogen peroxide dissolution method? Maybe not the fastest, but probably the easiest.
Attachment: murau1961.pdf (281kB)
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Melgar
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Quote: Originally posted by careysub  | Actually you should have 9.5 g of elemental thorium there, of about $3.50/g. Which is quite good.
Have you tried the hydrogen peroxide dissolution method? Maybe not the fastest, but probably the easiest. |
Yes. It used up 100 out of 500 mL of my 30% H2O2 and dissolved about a quarter of one rod. Maybe if I had a lot more of it, it'd be worth it.
I think I originally did the calculation assuming the 4% was mass of thorium metal, when it's mass of thorium dioxide.
I actually discovered that those cheap little USB phone chargers work surprisingly well for this. They have to have internal current
limiting, otherwise a phone that charges too fast could burn them out. Obviously, the ones rated with higher output amps work better. I went and
found my crappiest USB cable, the one that I had to twist exactly right to get to charge my phone, and cut the end off. There are four wires inside.
The black wire is ground and the red wire is +5V. The other two are for data. Soldered on some alligator clips, put a tungsten electrode and a
graphite electrode in the solution and let it go. It's already way ahead of the one dissolving in peroxide, and it's been less than a day.
Incidentally, tungstic acid is a pretty cool chemical to have as well. It can work with a phase transfer catalyst to perform hydrogen peroxide
oxidation in the organic phase, among many other interesting properties. And it looks like I sure will have a lot of it...
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careysub
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Yeah, if the 10 mL to 0.2 g ratio of the Murau article indicates what is required then your 270 g lot would almost 4 gallons. I can buy 30% H2O2 by
the gallon at a semi-local spa store, but still that's a lot.
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