Sciencemadness Discussion Board

The trials & tribulations of Thorium production

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Dan Vizine - 24-8-2016 at 05:53

I really hated to disappoint the collectors. But just because I won't be selling it myself, it will still be available in the near future from an approved source.

I have tried to conduct this as responsibly as my chemistry background permits, I don't release into the environment, my transfer of my washes to another was not probably OK, although I didn't know it at the time. And, it did serve as a way of having radiological test equipment check the environment when I was done. I expect that rational thought will normally prevail, and if this project is ever even noticed, it'll be obvious that this was a just a slightly less routine scientific experiment.

I have possession of all contaminated equipment (which is currently embedded in the center of a concrete cylinder). Fingers crossed that I haven't poked a dragon. But, it's a matter of public record so what will be, will be.

[Edited on 25-8-2016 by Dan Vizine]

blogfast25 - 24-8-2016 at 06:55

Quote: Originally posted by Dan Vizine  
Fingers crossed that I haven't poked a dragon.



This guy tickled the Dragon's tail and paid the price for it!

Dan Vizine - 24-8-2016 at 16:54

That was the so-called "Demon Pit". I think it claimed two lives. Another guy was stacking WC bricks around it and he slipped a bit.

Ozone - 24-8-2016 at 17:06

Yeah, that core smoked Harry Daghlian and Louis Slotin. Weapons-grade 239-Pu. Interestingly, the pre-critical moments appeared to have increased the yield of the core. Th, though, is a lazy kitten, and completely non fissile* (excepting, of course, transmutation of 232-Th to 233-U).

Still, one hell of a job Dan!

Cheers,

O3

*cannot reach criticality via spontaneous fission. Requires activation in-situ to yield fissile isotopes.

[Edited on 25-8-2016 by Ozone]

Dan Vizine - 24-8-2016 at 17:59

Really, the only fissile primordial metal is good old U-235. Not counting the numerous things darting in and out of existence in U samples.

blogfast25 - 25-8-2016 at 06:04

I wasn't referring to fission of course, only to the use of the word 'dragon', often used in the context of some criticality experiments.

Thorium is fissile though, see the upcoming generation of liquid fluoride thorium reactors.

After such extensive manipulation of significant amounts of Th, I would be concerned about residual contamination and airbornes.

It's why years ago I declined an offer for 25 g of high grade Uraninite because it's not something I'd like to process in a domestic area. Generating kg amounts of low radiation waste is also a concern, unless you can embed it in an immobilising medium and bury it on your own land.

Dan Vizine - 25-8-2016 at 18:31

As I understand it, Thorium is fertile and not fissile. It requires a source of neutrons to start it, usually an accelerator or another radioactive element. A pile of thorium as big as a house wouldn't start a spontaneous chain-reaction.

I have come to trust my lab skills so that I will work with liquid HCN, H2Se, HF, etc. without even having particular concern. As you'll recall, this method was explicitly chosen to avoid soluble thorium compounds. I have worked with as many potent carcinogens as you could care to name, so this was just another one. Many, many people in the NE live with so much Radon in their basements that the Th would be background noise. Everyday dust contains a degree of Th, cigarettes contain polonium, everybody my age is well familiar with strontium 90. It was in our snow. So, another exposure under my strictest controls, just another day at the office. As it is for all of us, like it or not.

TIG welders generate piles of Th particulates, yet you don't hear much about mass radiation-induced illnesses.

Multiple layers of gloves, carbon, felt and HEPA layered respirators. Bunny suits. Daily showers, clothes washing, and an unexpected once-through with a "large detector" alpha counter. Repainted the floors.

The aqueous washes were significantly reduced in volume by open-air evaporation and are no longer something I have control over anyway, as they were traded for the alpha testing. My residual equipment contains far less thorium than many totally unregulated old camera lenses. I don't undertake projects lightly, I mean to succeed and without causing harm. I sleep soundly on these issues. And if the FBI decides to investigate everyone with a thorium compound, they have a very long list. Thorium dioxide is currently listed on eBay and has been for years. A list of anyone who bought one of the countless ounces or pounds must be sizeable. Anyone who bought a pound of thorium dioxide had or has >4 times the amount of Th that I possessed. And theirs is much more dispersible.


[Edited on 26-8-2016 by Dan Vizine]

Ozone - 25-8-2016 at 19:36

Correct. It must be first activated to fissile 233-U (which is a natural isotope, but the abundance is too small to ever be useful, e.g. trace). This is done by layering with a critical fissile isotope like 239-Pu (a means of reducing the amount in the nuclear stockpile). Once it gets going, though, just add more Th.

Specific activity is dependent on half-life, which in this case (232-Th 1.405×10^10 y to 228-Ra) is *very* long. So, specific activity is very low. It would only be dangerous if reduced to small particles (self shielding falls apart around 700-800 nm for alphas of this energy) and inhaled. 238-U is more active, and it's pretty dead. But, it cranks out a beta on it's way to 238-Pu, which is a significantly hazardous isotope, but the number of nuclei would be exceedingly small (although the defense community is concerned about nano DUO2 from self-sharpening projectiles).

Given Dan's attention to detail, I wouldn't worry. Processing raw ore? I'd worry about keeping track of everything (much, much more radioactive) but the metal.

O3



[Edited on 26-8-2016 by Ozone]

j_sum1 - 25-8-2016 at 21:13

The thing that I think is amazing about the radioactive properties of thorium is that 8 grams is sufficient to run your car for 100 years.


[Ducks and runs....]

NEMO-Chemistry - 25-8-2016 at 23:16

Quote: Originally posted by j_sum1  
The thing that I think is amazing about the radioactive properties of thorium is that 8 grams is sufficient to run your car for 100 years.


[Ducks and runs....]


Not easy when most cars are only built to last 5 years :D.

Dan Vizine - 26-8-2016 at 18:06

Interestingly, we are approaching the point of minimum activity of this thorium. Those of you who followed the whole thread will recall conversations with annaandherdad about the effect of the aqueous phase precipitation of ThO2. He though it was a shame to lose the daughter products in a sample this old. I was thrilled about it. About 3 years after a chemical purification of Th, as daughters appear and disappear, you find the lowest activity that that Th sample will ever have (until the next purification). Not hugely significant, but I find that stuff interesting.

Ozone, you sound like someone I wish I had met earlier. Your knowledge level is obvious, the specifics rolling around in your head, hard to find. While I do have immense confidence in my ability to execute, so many uncertainties about this poison that I can't destroy did nag at me a lot during this project.

I'm actually more concerned about thorium that may or may not have been in lanthanides that I've sawed, polished, etc. (with a simple elephant truck exhaust) than I am about this synthesis.

Dan Vizine - 27-8-2016 at 19:54

How much thorium do you inhale in a lifetime simply by existing?

The average person breathes 48 lbs of dust in a lifetime.

45% of dust is soil.

The amount of soil you breathe over a lifetime is thus (454 g/lb) (48 lbs) (45% soil) = 9.8 kg

Soil is, on average 0.000008 thorium.

9.8 kg @ 8 ppm = ~ 80 mg

So, you breathe roughly a tenth of a gram of Th over a lifetime. Interesting.

phlogiston - 12-12-2016 at 07:04

That is a surprisingly large amount. I wander how much of it retained for long periods of time. Also, it must be quite a lot more if your were a confederate soldier and your dentist could not tell tin from thorium:

From Dental Filling Materials in the Confederacy
Quote:
Dental fillings are known from seven Confederate specimens. The first four specimens were collected for their anatomical and pathological value, and the filling materials have been chemically analyzed. Three of these four specimens were from the Battle of the Wilderness and one from Bull Run. These dentitions were curated in the collections of the National Museum of Health and Medicine, Armed Forces Institute of Pathology (AFIP).' The first anatomical specimen (AFIP 1001810) from the Battle of the Wilderness had a filling in tooth no. 2. The filling is thorium, which was radioactive, and lesser amounts of other elements. The dentist who placed the thorium, radioactivity being unknown at that time, may have thought that he was working with a variety of tin.


[Edited on 12-12-2016 by phlogiston]

Dan Vizine - 12-12-2016 at 09:47

Hi phlogiston,

When you breathe Th, I think the main problem is actually the daughter products. Whatever does decay to Radium, will be taken up in the bones. I have a long file entitled "Toxicological Profile of Thorium". Here is an excerpt:

"Only a small amount of the thorium that you breathe or swallow in food, water, or soil enters your blood. One animal study has shown that thorium can enter the body if it is placed on the skin. After breathing thorium, you will usually sneeze, cough, or breathe out some of it within minutes. Some forms of thorium can stay in your lungs for long periods of time. However, in most cases, the small amount of thorium left in your lungs will leave your body in the feces and urine within days. After you eat or drink thorium, almost all of it leaves your body in the feces. The small amount of thorium left in your body may enter your bones from the blood and stay there for many years. The main way thorium will enter your body is by breathing dust contaminated with thorium."

I'm surprised to see the claim that inhaled Th is cleared so readily. Presumably, this must mean that the inhaled form must have some solubility in bodily fluids. I'm sure ThO2, for example, doesn't clear this readily.

It's curious that they could have confused Th with Sn. Th is similarly soft, but the mp is even above that of Pt. It must have been a powder. But, where in the world did it come from??

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

Dan Vizine - 20-12-2016 at 08:05

Quote: Originally posted by Magpie  
What has been your experience with pin-hole leaks in stainless steel? Is this a common experience with 0.125" wall steel? Especially under low pressure (5" Hg).


Upon thinking more about it, followed by some additional digging, I've revised my thinking on the cause of the tiny, possibly self-sealing leak. I believe it had to do with heat-induced stress.

The term usually applied to the phenomenon is hoop stress. Hoop stress is considerable in SS alloys. It also explains why the pro welder said that welding a gas-tight right cylinder is fairly impossible with an AC stick. Hoop stress is explained here: https://en.wikipedia.org/wiki/Cylinder_stress

My reactor, with O.125" walls and radius = 1", would be considered under the "thick-walled" heading.

A rounded bottom would have been a superior choice to a flat one. The stresses due to differential expansion would not have been concentrated at an edge, where the flat bottom joined the wall.

neptunium - 2-8-2018 at 14:05

I know this is a little off topic but still..I have been trying to isolate thorium from monazite and i thought a bit of help from SM wouldnt hurt..
here where i am so far..

https://www.youtube.com/watch?v=KSNHRjp9QiI

MJ101 - 3-8-2018 at 07:35

@Dan Vizine: I read this thread from stem to stern. Awesome science! Awesome Engineering!

Dan Vizine - 7-8-2018 at 15:05

Quote: Originally posted by MJ101  
@Dan Vizine: I read this thread from stem to stern. Awesome science! Awesome Engineering!




It was the project of a lifetime. A number of people here provided great suggestions. In the time since this was completed I decided to put it on YouTube:
https://www.youtube.com/watch?v=n4Uwxcb62gE

j_sum1 - 7-8-2018 at 22:17

Awesome. Thanks Dan. I am looking forward to sitting down and watching this. I'll probably have a bunch of questions afterwards.

Hendrik - 7-8-2018 at 22:53

This was an awesome project! Now the YouTube amateur chemistry community has three showcased videos on actinides: thorium, uranium and americium!

Dan Vizine - 8-8-2018 at 06:22

Quote: Originally posted by neptunium  
I know this is a little off topic but still..I have been trying to isolate thorium from monazite and i thought a bit of help from SM wouldnt hurt..
here where i am so far..

https://www.youtube.com/watch?v=KSNHRjp9QiI



Neptunium,

That's a very nice piece of work. I'll be watching to see how you do your separations. You have a unique home lab, the XRD was a total surprise.

Dan Vizine - 3-10-2018 at 19:08

Obviously, with Th in a powdered form, inhalation danger is a primary issue.

An interesting calculation is to divide the maximum allowed body limit for insoluble Th 232 (lung only), which is 0.002 microcuries, by the specific activity of natural Th 232, 2.2 E -7 curies/gram, to obtain a maximum allowed lung burden of approximately 9 mg.

Melgar - 3-10-2018 at 23:45

Hey Dan, how's it going? Running low on nitric acid by any chance? I was thinking of getting more at some point in the near future.

Also, have you done anything fun with the sodium cyanide? I've done alkaline silver and copper plating from scratch now, as well as acid plating with nickel and copper. But other than making Prussian blue, my cyanide experiments have been pretty limited.

I'm working on upgrading this site's software, and have a test version of the software with old forum data up and running.

[Edited on 10/4/18 by Melgar]

SWIM - 4-10-2018 at 17:48

As for the thorium filling,

It was probably a foil that was used. They'd force foils into the cavity really, really hard and it would kind of fuse.
At least this was done with some other metals in the pre-amalgam era. (Yeah, I am actually a dental history enthusiast)

Quite a thread, but the Barium one's pretty cool too.

Dan Vizine - 6-1-2019 at 14:39

Quote: Originally posted by Melgar  
Hey Dan, how's it going? Running low on nitric acid by any chance? I was thinking of getting more at some point in the near future.

Also, have you done anything fun with the sodium cyanide? I've done alkaline silver and copper plating from scratch now, as well as acid plating with nickel and copper. But other than making Prussian blue, my cyanide experiments have been pretty limited.

I'm working on upgrading this site's software, and have a test version of the software with old forum data up and running.

[Edited on 10/4/18 by Melgar]


Hi Melgar!
Nice to hear from you. Please forgive the lateness of this reply, I haven't looked at this thread in months.

I'm still holding well on both HNO3 and the NaCN, thank you. I actually haven't any call to use cyanide since I bought it. But it's nice to have in stock. The Nitric acid is another story. I've used about 1/2 of it over the many months since I bought it. However, I still have a year's supply based on present usage.

I want to sincerely thank you for your offer to procure more, that's a very selfless offer to make. May your 2019 bring you nothing but happiness.
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