Sciencemadness Discussion Board

The trials & tribulations of Thorium production

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Dan Vizine - 13-9-2014 at 13:08

careysub, I tend to see it like Pok does. For this project, radioactivity is only incidental, just another hazard to be worked around. The thrust of this project is really meant to be about using metal reagents to prepare other pure metals by thermochemical means.

Damn, that procedure was harder than I had hoped. It took a full hour of hard work with a nice, clean rasp to reduce my 99.9% Ca ingots to silvery filings stored under UHP argon. This is about 25 grams. At least this represents most of what I'll need.

Now...it's time to travel again. Next week is going to be spent in Atlanta, GA. Work, not fun. Anyway, further experimental progress will just have to wait.

Ca.jpg - 344kB

[Edited on 13-9-2014 by Dan Vizine]

Dan Vizine - 22-9-2014 at 12:25

I've tried as much as possible to obtain my reactants in small particle sizes.

One reduction oriented paper (attached) mentions occasional low yields thought to arise from poor blending. Small wonder, I guess, given the significantly different natures of the reactants, a very fine powder of fairly low density, a coarser powder of much denser material and relatively large particles of a light-weight metal.

At temperature, the Ca and CaCl2 will be liquid. But, if any coarser, denser thoria settles in a layer above the still denser thorium metal below it, it may fail to react throughout its thickness. That may explain the possible mechanism and it concerns me.

I had planned agitation all along but my "means" were DOA. Then, I figured I'd do it by hand for the 1 hour reaction period (usually specified). However, I noticed that the worker's method that I am following specifies soaking at temperature for 5 hours. Too long for effective (even if intermittent) agitation by hand. I need something that will rotate the reactor back and forth around its long axis.

If the pipe suspending the reactor is constrained to only move through a limited angle around the long axis, say ~ 90 degrees, and a spring holds it at one end of the allowed range, then a device which pushes the pipe to cause it to rotate through a small angle before releasing it to be returned to its originally spring-dictated position will achieve what I need.

I dug out this old unit which may serve the purpose. It's a bastard hybrid made from part of an hplc pump and a large old printer motor. It gives a slow, adjustable rotation to operate the "pusher" mechanism.

drive.jpg - 1.9MB

Attachment: Production of Thorium Powder by Calcium Reduction of Thorium Oxide.pdf (159kB)
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Dan Vizine - 29-9-2014 at 14:14

Well, the apparatus is nearly done. I need to set up a suckback-proof mercury bubbler with a mercury depth of 5 inches, set up an argon line from the basement, dry the finely ground CaCl2, leak-test the reactor and ancillary piping, make a head for the reactor tube that will deliver argon well down inside the tube (just above the reactor) and I think that's it.

I tried out the agitation system. It makes a little noise, but it's not too bad. It works exactly as I hoped in would. The speed of the pusher motor is Variac controlled. Depending on my day job's demands, I hope to do the reaction in October.


the setup.jpg - 438kB

Dan Vizine - 7-10-2014 at 18:55

Some things I've been finding....

Robert Alvarez, Institute for Policy Studies, February 2014

The surface dose rate from a 55 gallon drum of thorium oxide is approximately 60 mR/hr--about 13 times higher than from a similar-sized drum of uranium. A worker spending time inside a thorium storage facility could expect to encounter dose rates of 60–100 mR/hr. In a little over six working days, such an employee could reach the maximum annual U.S. occupational exposure limit of 5 rem.

--Just further reassurance that the risk is managed.



Interim Report on Metallurgy of Thorium and Thorium Alloys, Co n t r a c t No. W-7405, eng-26 by J. H. Frye, J r . , Director ORNL Metallurgy Division-Declassified

Westinghouse Thorium - The. starting material for Westinghouse thorium is thorium oxide. The oxide is reduced with calcium, the reduction being carried out in a steel crucible in a steel bomb. The crucible is llned with molybdenum so the calcium will not teact with the steel at high temperatures. The charge is thoria with an excess of 100% calcium placed in alternate layes in the crucible. The bomb assembly, with an argon atmosphere, is placed in a furnace at 1200° C. When the reaction is complete, the bomb is slow-cooled and not opened until the temperature falls below 100° C because of the high reactivity of thorium with oxygen. The charge and crucible are placed in a leaching tank of cold wate and glacial acetic acid equivalent to the total amount of calcium charged. The powder is filtered, washed with alcohol, and vacuum dried. The powder is then compacted a pressures varying frdm 2-10 tons per square inch. The bars are slowly heated to 1450° C in vacuum and sintered at temperature for 30 min.

--Just something else to fret about......SS304 + Ca @ 1050 C, will that be an issue? Guess I need to do a bit more research on the ability of the metal to resist the hot Ca. Generally speaking, the more nickel, the worse the metal is for containing molten metals like Ca. Wouldn't that be a mess, if it failed during reduction? Sobering thought. Maybe I should just do a dry run with only Ca and CaCl2 first?

--Another worry, SS hates chlorides, aqueous anyway. Need to find definitive SS 304 resistance information, I guess, for more than one reason.

--But, on the plus side, I like the implications of the line "...placed in alternate layes in the crucible". Maybe I don't need to worry if my ThO2 particle size is small enough.


And, Th is melted by VAR on a water-cooled copper hearth in a vacuum or under inert gas. So, no worries there.

Dan Vizine - 8-10-2014 at 05:26

And finally, some additional info. re. VAR.....

Attachment: Radiation Hazards Encountered in Arc Melting Thorium.pdf (1.4MB)
This file has been downloaded 198 times


MrHomeScientist - 8-10-2014 at 06:01

Really great project Dan, and a very interesting read. Steadily making progress!

Dan Vizine - 8-10-2014 at 06:56

Thank you, Mr.HomeScientist.

I think sometimes that members must be thinking "C'mon, already. Are you ever going to do the freakin' reaction?"

I'm trying to go at a good enough rate but there are any number of devils lurking in the details and I have to address every one.

The latest reason to lose sleep:
The production of ingots by consumable-electrode arc melting in vacuum or inert atmospheres has been successfully applied t o the processing of many reactive metals including thorium. The melting process begins with the formation of an electrode. In the case of thorium this electrode can consist of sawed bomb regulus bars butt-welded together or a previously induction-melted or arc-melted ingot. The electrode is mounted vertically in an appropriate furnace such as shown in figure 2 and is consumed by heat from a high-current electric arc that burns at the lower end of the electrode. The metal consumed by the arc drops into a water-cooled copper crucible where an ingot is formed by solidification . When the ingot is completely cool, the furnace is opened, and the ingot is removed from the crucible for machining. Sometimes it is necessary to remelt or "double-melt" to obtain homogeneity. A complete description of the consumable-electrode arc-melting procedure for thorium was given by Roberson and Beall (14).

Okayyyy.....so I need a thorium bar to make a thorium ingot? Isn't that just great? Damn it, damn it, damn it! I should have known, that's what stings. What else could they have used without adding contaminates?

Time to track down that reference if I can. It doesn't look like a walk in the park...

ROBERSON, A. H., AND BEALL, R. A. Consumable Electrode Arc Melting of Thorium: Chapter in the Metal Thorium. A.S.M. and A.E.C. Symposium on Thorium, Cleveland, Ohio, copyright 1958, .397 pp.

Update: Well, I can't find the above reference. But I found this (which I could not download):

authors.jpg - 26kB W is OK.jpg - 29kB

So, it looks like a non-consumable W electrode can work.

[Edited on 8-10-2014 by Dan Vizine]

bobm4360 - 8-10-2014 at 08:38

Here's the report.
Regards,
Bob

Attachment: IS-262.pdf (1.5MB)
This file has been downloaded 215 times


Dan Vizine - 8-10-2014 at 10:16

Hi Bob,

Very grateful for the reference.

Thanks,

Dan

phlogiston - 8-10-2014 at 15:13

Quote: Originally posted by Dan Vizine  

I think sometimes that members must be thinking "C'mon, already. Are you ever going to do the freakin' reaction?"


On the contrary, it is refreshing and very stimulating to see someone plan his experiments very carefully, considering every potential problem and devicing a solution.

This is a great thread! thank alot for sharing your efforts, including the details of your considerations and preparing your setup.

Dan Vizine - 29-10-2014 at 08:36

In light of the below conversation, I purchased a sheet of 309 SS and a new reactor will be constructed.
**********************************************************
Yesterday I contacted a British SS firm to ask about the suggested material of construction to stand up to molten Ca/CaCl2 at 1050 C for 5 hours. Today, I received this reply from their resident metals expert. This is in relation to my ongoing calciothermic reduction of ThO2 project. Interestingly, SS 446 is what the original Sylvania researchers used...

"The combination of molten calcium and calcium chloride salt is a difficult combination for most materials. Molten calcium can cause cracking of RA330 and nickel based alloys. On the other hand calcium chloride molten salts in the presence of oxygen fluxes the scale eating away at the chromium oxide coating. In these applications RA330 or 600 are alloys of choice. Since you have both, you now need a compromise, If the temperature were lower, 309 would be a good choice, but at 1050 C, you are above the oxidation limit. RA 253 MA could be a reasonable compromise, given the sublayer of silica and RA330 is the only other potential compromise. Keep in mind that the oxidation limit of RA 253 MA is 1090, a temperature surge that takes the metal above this temperature, could have adverse affects of RA 253 MA, in terms of breakdown of the oxide and leaching. RA 253 MA also has better creep strength at this temperature. So the question is just how well can you control the temperature of the metal of construction. Regardless of the material, there is not certainty that either will work, only the possibility. The 446 that you mention has not strength or ductility at this temperature. I am attaching an article on materials for salt bath construction. Pay close attention to the comments on properly maintaining the salt as the maintenance is the key to attaining a reasonable life."

Attachment: SALT POTS.pdf (308kB)
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I replied as follows:
Thank you for your detailed answer. I was aware that molten Ca was aggressive toward Ni based alloys, hence the worry that the 304 SS bomb that I have may not work.

I’m attempting to duplicate work performed by Sylvania researchers 50+ years ago. They employed 446 for the bomb reactor. I was hoping a more accessible alloy might work well enough. If I can maintain the level of leached metallic impurities below 1 % I would be happy. I plan to have the product powder vacuum arc re-melted to give beads, which I understand will sometimes actually improve purity slightly.
-
Here are a few more details: A metal oxide (ThO2) was combined with Ca + CaCl2 in a SS 446 bomb. The bomb was heated in a furnace while being maintained at 1050 C under an atmosphere of UHP argon supplied at a continual pressure (via external pipe) of 5 in Hg.

I assumed that the protective oxide on the bomb interior would be destroyed quickly by these strenuously reducing conditions and couldn’t be counted on to provide any protection whatsoever. The oxide would, of course, protect the outside somewhat. Is this assumption wrong?

Would being above the oxidation temperature of SS 309 matter under these circumstances? Oxidation will only attack the outside of the bomb and past experience in metal melting in SS 304 has shown that despite heavy scale formation, the 304 metal will maintain structural integrity over many melts of copper and brass. So my concern really centers on the question of what effect will be felt by the bomb interior from this Ca/CaCl2 mixture over the projected 2 heating cycles. I plan two 5 hour runs.

Upon re-visiting the different papers that I have gathered regarding the reduction, I realize that I quoted the wrong conditions.
Both of these variants worked:
1) 5 hours at 950 C
OR
2) 1 hour at 1050 C.

Does a 950 C reaction temp bode any better for my existing reactor of 1/8 “ SS 304?

My temperature control should be sufficiently good that I can keep things at desired temperature +/- 10 C. The reduction of ThO2 is barely exothermic and so it shouldn’t be a big factor. The original workers didn’t even mention one.

And lastly, even though the Th raises eyebrows, this is obviously not a “terrorist” type project. If I were planning something nasty, the powdery ThO2 that I have already would be the material of choice. I want to turn this into small beads of metal for sale to element collectors, thorium being one of the hardest samples to obtain. I have a deadline, too. After Jan 1, 2015 I won’t be able to sell without a license in the US and this is just a basement project by a retired chemist.


And the answer I received:

Dan:
The 950 C temperature is still well above the limit of 304 SS. However, at the 950 temperature, 309 stainless would be a reasonable alternative that could withstand both of these conditions. 446 is a ferritic stainless steel and will be hard to find, as quality ferritic stainless steels are not being produced in the US anymore unless one is willing to buy a full heat quantity.

So, the news is mixed (for me anyway). SS 309 can be found but I will need to construct a whole new reactor from it.

Dan Vizine - 29-10-2014 at 14:17

Wait.......

Did he think the molten salt was on the outside?!

I don't think we were talking about the same thing....

blogfast25 - 30-10-2014 at 11:09

Quote: Originally posted by Dan Vizine  
Did he think the molten salt was on the outside?!



Reading his reply I don't get that impression.

Dan Vizine - 5-11-2014 at 14:50

The SS 309 plate arrived. I just finished cutting and forming the pieces. This is a roomy reactor, 1.9 inches ID x 3.9 inches tall (interior), ~ 11 cubic inches, about 180 mL. I decided that I'd get it professionally welded for safety reasons. Full penetration TIG welds with SS 309 wire.

The first shop that I called turned me down for liability reasons, but not the ones you might have guessed. It's because it's a vessel. Vessels are a special subset of welded articles. You need special certs. to do that kind of welding for hire because of the obvious reason...vessels shouldn't fail because of the extreme danger some failures could cause, say a propane tank, for example.

But the second shop was more accommodating. When the female 1/2" SS coupling gets here, he'll do it for maybe $50.

So, here it is, forming was done on a hydraulic press around a 2" diameter cylindrical steel form. The edges to be joined take a bit of a beating during forming, so everything was trued up on a horizontal metal-cutting band saw by slicing away the damaged edges, which is why the cylinder is just below round numbers in dimensions. This gives pieces which fit together very well.

The project keeps inching along at glacial speed.

I think this was the last major hurtle. The title of this thread is more and more apropos by the day.

DSCF2594.JPG - 1.4MB

edit~

I was just thinking about agitation. I wonder if a few maybe 1/4" dia. tantalum balls would be beneficial to add for stirring? It's tough to guess. Is the acceleration and length of the arc it moves through enough to cause the beads to plow through the starting thorium dioxide and, later, through the Th metal powder?

There is probably (high probability) no downside, I guess, other than potentially wasted time and Ta. Ta likely has very low solubility in thorium, probably 50 - 100 less than the Fe in the reactor, so it shouldn't cause a contamination issue.



[Edited on 6-11-2014 by Dan Vizine]

phlogiston - 5-11-2014 at 23:51

That's beautiful.

Given that the atomic radii of tantalum and iron are similar (145 pm and 140 pm respectively), why do you predict Ta is not likely to be also somewhat soluble in Th?

Do you intend to rotate/shake the reactor to move the Ta balls around, or would you add them in addition to the stirrer you made in september?

Impressive work, love reading it, thanks.

[Edited on 6-11-2014 by phlogiston]

Dan Vizine - 6-11-2014 at 09:39

Oops...my bad. The thorium won't be molten at any point.

"Ta likely has very low solubility in thorium, probably 50 - 100 less than the Fe...."

Should have read:

"Ta likely has very low solubility in calcium, probably 50 - 100 less than the Fe...."

It's often said that final product purity depends mostly on the purity of reactants in these direct oxide reductions, and anything found in or dissolved in the Ca largely ends up in the thorium.

I'd just add them to the reaction mixture and let them roll around as the reactor moves like a "standard" washing machine agitator does.

Thanks for the kind words, I'm happy that you enjoy it!



[Edited on 6-11-2014 by Dan Vizine]

Arcuritech - 7-11-2014 at 08:37

As far as melting the thorium goes, why not use an induction heater? They don't use them industrially because of scaling problems but on the home scale it seem perfectly workable. The best part is that this won't even involve direct contact - no need for HV feedthroughs into whatever you're using as an inert environment.

Dan Vizine - 7-11-2014 at 12:49

The most successful bomb reductions were done exactly that way......in a refractory metal crucible, under a quartz bell jar and heated by induction. It would be wonderful, got one to loan me?

Here is a collection of information about the distinct types of liquid metal attack on other metals.

Attachment: Types of liquid-metal corrosion attack .docx (741kB)
This file has been downloaded 226 times


Arcuritech - 11-11-2014 at 06:37

I don't have high power LC resonators to throw around but they are pretty easy to make as long as you aren't frightened by moderately high voltage electricity.

froot - 11-11-2014 at 08:42

Some heat treatment companies use induction heating to case harden metal components, when you get to that point it may be worth calling up a few of them and hopefully you find an obliging person to assist you. You would need to build your furnace setup with the induction coil in it which is usually a copper tube fashioned into a coil with contact plates brazed onto it.

Dan Vizine - 11-11-2014 at 19:15

I have no reservations at all about high voltages, building control/power electronics was a hobby once. If not for the cost of the electronics, this is something I'd have built long ago to support my metal-melting activities. But, the point is, once I built an induction heater, then what? Then, I'd need to buy a Vycor bell jar or similar. Then, to take advantage of the improvements these offer, I'd be obliged to obtain a molybdenum crucible. We're talking real time and money. It would be great, but not practical.

My approaches often come from having worked in synthesis all my life. One of the skills that you really come to prize is the ability to achieve good results with the minimum practical outlay of effort and money while pushing your existing, or practically obtainable, equipment to the safe limit of its performance. And hopefully innovating some things along the way. I've attempted to continue that discipline here. "Don't let the perfect be the enemy of the good" is some of the best advice I've ever heard, given our finite nature.

On the technical side, I'd like to mention a few "fall-back" options that I do have, or maybe I should more accurately call them remediation steps. The process of arc melting in vacuo is actually also a purification procedure. The crude Th powder will undoubtedly contain carbon, chromium, nickel, iron, oxygen, calcium and other trace elements. The desired final product should be malleable. Inclusion of tiny amounts of impurities can drastically harden the metal by blocking slip planes. Transition metal impurities will typically show up this way, although even gas atoms can have this effect. Impurities that volatilize, with or without dissociation, at thorium's mp will be minimized unless they're firmly bound, as for example, oxygen will be by thorium. A sign of good quality metal is fairly reliably indicated by the ability of the metal to resist appreciable darkening in air. Excessive oxide causes the metal to darken quickly. Even the best thorium products typically have several tenths of a per cent oxygen. Malleability will be the main yardstick of purity but it will be supplemented by oxidation resistance.

The next step would be used only if absolutely necessary and it is the "crystal bar" purification method using iodine as a carrier. It would give a gorgeous product, but would involve so much development effort that I'd probably reprocess via the fluoride and reduce to metal again.

About a commercial assist...even if they could get past the "radioactive" part, you'd still need a nearly perfect blanket of UHP argon. My electric furnace will maintain the required 950 C for 5 hours with absolutely no sweat and with my argon tank parked along side. Simple, straightforward....

[Edited on 12-11-2014 by Dan Vizine]

Dan Vizine - 12-1-2015 at 15:36

After 2+ weeks of waiting because of the welding company's busy schedule, another week when his [the welder's] "machine was being fixed" and more time as he promised to get it done, but then didn't, I retrieved my un-welded parts, only to start looking for another welder. A big-time concern just down the road, Goergen-Mackwirth Co., said they'd do it for around $200.00. As I said, the hunt for a suitable shop continues. The first shop had quoted $50 -60.

Dan Vizine - 15-1-2015 at 20:59

Hmmm...traveling again. You'd think a trip across the Atlantic would be fun unless you knew you were headed for Saudi Arabia. Actually, Israel first. Then into the middle ages.....

Wikitravel reports:

My Kingdom will survive only insofar as it remains a country difficult to access, where the foreigner will have no other aim, with his task fulfilled, but to get out. -- King Abdul Aziz bin Saud, c. 1930

I see.....

Saudi Arabia has some of the most restrictive travel policies in the world, and advance visas are required for all foreigners desiring to enter............ Nationals of Israel and those with evidence of visiting Israel will be denied visas, although merely being Jewish in and of itself is not a disqualifying factor.

I don’t understand what this means. I’ll be coming from Israel. Which is very clear evidence of visiting Israel. But there are airlines that fly from Israel to Saudi Arabia, so I'm completely confused. Or is that only for passengers transiting through Saudi Arabia, coming from Israel? Not for those actually staying in Saudi Arabia? Not a single human answered my calls at any SA Consulate in NYC, Washington or Houston.

Also from Wikitravel:

Hepatitis and Meningitis vaccinations are required for general travel to the Kingdom. OK, not unreasonable..

Driving in Saudi Arabia is not regulated and rules are not followed, thus Saudi Arabia has the highest incidence of car accident fatalities in the world. It is common to find drivers driving against the traffic on full speed. (Oh, and police officers often decide accident responsibilities and punishments at the scene). Getting pretty weird now.....

Be careful of unregistered cars claiming to be taxis. If possible, always ride with a friend who knows the country. There are no street addresses in Saudi Arabia, so you will have to know your route well, and pay attention to the road to explain to the driver where to turn. How quaint and disturbing....

Malaria, Dengue fever and the new SARS-like Coronavirus (Middle Eastern Respiratory Syndrome - Coronavirus "MERS-CoV") are major concerns when travelling to Saudi Arabia and all cause death if acquired. Public and private hospitals in Saudi Arabia, by law, do not admit foreigners even with health insurance and during a life threatening emergency. What?!! Are you kidding me? Now, it would seem they've crossed the line into institutionalized inhumanity.

Oh, and I'll be traveling to Osama Bin Laden's Alma Mater to work. Wonder if they have yearbooks? President of the chess club, maybe?
Most likely to be the hide and seek champion, 2001-2011?

The joys never end. At least I'm nowhere near Yemen (you know they're all half-crazy, right?).

All western joys are forbidden, except to the wealthy, who can flaunt the laws.

The King was truly prophetic in his words, I can't wait to get in and back out again as soon as humanly possible. If there's a flight I can catch after work, no matter what time, I'm on it and gone forever.

Israel might be interesting if I were religious, and so it won't be in the slightest. Two exotic countries without a shred of interest. In Israel, Nazareth is down the road a bit, be it city or band, not interested.

Oh yeah, almost forgot the cherry in Saudi Arabia...According to a 2014 poll, King Abdulaziz International Airport was voted as the second worst airport in the world. And, did I mention that the mosques will sound off at 5 AM? Gives you at least an hour to lay there and think of how badly you don't want to be there.

If you don't hear from me again, it'll probably be because I expressed a true opinion and was jailed. You DON'T insult the government, actually "The House of Saud".

Just more delays in the work I want to do.



[Edited on 16-1-2015 by Dan Vizine]

Dan Vizine - 20-1-2015 at 09:52

Saudi Arabian trip otherwise accomplished, Israeli trip still on.

Meanwhile, I can't believe how hard it is to find somebody who will do 10 inches of MIG/TIG welding for less than $200 plus. That's damn near the cost of a entry level MIG.

I just found out that the person who I was counting on to do the vacuum arc remelting, misunderstood the nature of the material to be melted. He won't do it. That leaves hydraulic compaction as the only available option left to me.

I wish I had some actual science to report on, I know this is not particularly interesting reading. Oh, for a good laugh you could head over to my Barium enema, excuse me, that's animus thread to see how barium is kicking my ass.

Chemosynthesis - 20-1-2015 at 11:57

I hope you have some entertaining stories (or perhaps videos) from your travels.

As for welding, I am sorry to hear. I met a master welder recently, and it's really fascinating to see how they can bill.

careysub - 20-1-2015 at 13:48

Quote: Originally posted by Dan Vizine  

Saudi Arabia has some of the most restrictive travel policies in the world, and advance visas are required for all foreigners desiring to enter............ Nationals of Israel and those with evidence of visiting Israel will be denied visas, although merely being Jewish in and of itself is not a disqualifying factor.[/color]

I don’t understand what this means. I’ll be coming from Israel. Which is very clear evidence of visiting Israel. But there are airlines that fly from Israel to Saudi Arabia, so I'm completely confused.


I don't believe there are any airlines flying direct between Israel and Saudi Arabia.

Muslims from Israel or Palestinian Territories wishing to go on Hajj must take buses to Jordan and fly from there.

In the past when people were travelling to Israel and then going to Saudi Arabia the Israelis would not stamp your passport as having entered Israel. Saudis might be able to infer that you had come through Israel, but without the stamp they could officially be ignorant.
Quote:
(Oh, and police officers often decide accident responsibilities and punishments at the scene).[/color] Getting pretty weird now.....

Public and private hospitals in Saudi Arabia, by law, do not admit foreigners even with health insurance and during a life threatening emergency. What?!! Are you kidding me? Now, it would seem they've crossed the line into institutionalized inhumanity.

All western joys are forbidden, except to the wealthy, who can flaunt the laws.


Saudi Arabia ranks almost at the very bottom of The Economist's ranking of totalitarian states, beaten only by North Korea (last I checked).

They've been good buddies of the U.S. though ever since, well, oil.

Quote:
Israel might be interesting if I were religious, and so it won't be in the slightest.


Not interested in history? Lots of it there - from prehistoric times, ancient civilization, to Medieval and later civilization.

Dan Vizine - 20-1-2015 at 20:59

Quote: Originally posted by careysub  


Not interested in history? Lots of it there - from prehistoric times, ancient civilization, to Medieval and later civilization.


On the contrary, when I was in China and Belgium, the history was fascinating. And the buildings and everything were phenomenal from Brugge to Shanghai. I walked Chinese streets built in 1500 AD and climbed steeples in Brugge halfway to the sky. The history was overwhelming, being American and all.

In fact, since seeing Belgium, I've seen a life I'd rather have lived than being an American (well, after the 60's anyway, the 60's in the US was the single most exciting time and place to live in the world if you're of a particular persuasion). But the history of the area of the middle east that I'll be in...well, first word that pops into my mind is strife. You may be right, and it may have attractions but I just don't know of anything that I'm anxious to see there. I hope I'm surprised.


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

careysub - 21-1-2015 at 12:58

Quote: Originally posted by Dan Vizine  
You may be right, and it may have attractions but I just don't know of anything that I'm anxious to see there. I hope I'm surprised.


Some notable examples:
Jericho - the oldest continuously occupied city in the world (and one of the oldest, period).
Excellent Roman ruins in Caesarea, and Roman roads throughout Israel.
Crusader fortresses - Belvoir near the Sea of Galilee, Nimrod in the Golan (my favorite - spectacular view)
Jerusalem itself is a 3000 year old city, with excavated sites of interest spanning the entire period (the underground passage to the Siloam Spring dug 2800 years ago is impressive). Much impressive religious architecture of course, starting with the whole Temple Mountain (Mount Moriah). Impressive ancient tombs galore.
The Nabatean city of Avdat in the Negev (also spectacular).
Masada is very impressive - a palace/fortress of Herod I on top of a dramatic pinnacle, with the siege ramp built by the X Roman Legion still in place.
Lots of famous ancient battle sites.

Natural wonders: the Dead Sea (and whole Jordan Rift Valley); Makhtesh Ramon - a huge erosion crater, a landform apparently unique to Israel and the Sinai.
Bird watchers like Israel as it is a crucial migration corridor between Africa and northern Eurasia.

[Edited on 21-1-2015 by careysub]

Dan Vizine - 22-1-2015 at 20:59

Well, if this is a typical trip, It's 18 hrs flying time and I won't sleep, I'll arive, get to Haifa, eat and sleep. Next day work into early evening, a few hours off, sleep, repeat 1X. Travel to Tel Aviv, have a few hours, pack, sleep and return in a %^&$* middle seat. My opportunities for sightseeing will be really limited. I didn't arrange any extra time. Sightseeing usually depends on if I go out drinking with the grad students (Bless you my Belgian Friends!) on most trips, when I go to industries, we never,ever end up partying after work.

I so hope the next long trip is to Europe or thereabout, we're putting units into Berlin (M. Braun's backyard...prolonged snicker), Sweden and another in Great Britain, but none of them ordered the installation package, me.

NOW...for the news. I found a young, highly skilled welder who has welded SS tanks for the pharma companies. He said a few days, $100. I'll finally have the reactor I need.

Dan Vizine - 25-1-2015 at 14:25

And done.....

He asked for $150, took $130 instead of estimated ~$100 because he had to buy the wire and refill his argon tank. I kinda thought it was implied that he had this stuff when he took the job. I probably would have looked for another welder who would only charge for labor and the materials used, but we agreed to $130 and I thanked him. I pressure tested it. Perfect. He inerted the inside during the weld, gave a real clean product.

There's not much more to do except consider my newly acquired ability to do possible ball-milling of the ThO2. I have mixed feelings. It sounds good, I think the best way to avoid ThO2 contamination of the product, besides the obvious, is to minimize particle size. I just don't want my grinding media to end up in the product.

I'm getting excited about this, all of the real challenges have been addressed to the best of my [practical] abilities. Cost overruns have appeared from time to time. Investment is now around $800 but shouldn't go much higher.

And, I now I have a glovebox to handle the product powder in. Good stuff.

I'm just hoping people will be interested in powdered or room temp "pressure-sintered" forms. It's pretty much going to be the only stuff around, except for those very infrequent ebay offerings (the last one I saw was about 0.1 g for $200). Ridiculous. Fingers crossed.

Now, if I didn't have an appointment in Israel followed by Ga. again, it would be clear sailing. Stay tuned, it WILL happen...

SS 309 Reactor.JPG - 2MB

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

MrHomeScientist - 26-1-2015 at 08:02

While I normally avoid powders, I'd make an exception here knowing the extreme time and effort you put into making this product. Sign me up for a sample when it's finally finished! Really great work here.

Thorium from oxide

anolog - 27-1-2015 at 12:40

The most efficient method to produce thorium metal is reducing the thorium dioxide with combined powder of an alkali metal and an alkaline earth halide.
Thorium of a purity greater than 99 % by weight can be prepared by reacting thorium dioxide at 900-1000°C with calcium halide and alkali metal.
Optimal results can be obtained if these amounts are used, for every mole of thorium dioxide, at least 6 moles of calcium halide and at least 8 moles of alkali metal.
Following equation:
2 CaX2 + 4M +ThO2 → Th + 2CaO + 4 MX
2 CaCl2 + 4 Na + ThO2 → Th + 2 CaO + 4 NaCl
If reducing agents are used less than the above stated amounts, then usually the purity of the thorium falls to 90%.
Heat the mixture in an electric furnace temperature of 900-1000°C. Under a nobel gas atmosphere, let it react for 30 minutes, and turn off the heat and let it cool.
Then wash the mixture with 30% acetic acid with continuous stirring until bubbling stops, then filter it and wash the precipitate with alcohol and few times with hot water and filter it. Now you should have thorium powder, it should look like platinum powder.
The thorium powder should be stored in nobel gas atmosphere or melted to solid chunk because in it’s powder form it is pyrophoric.


Attachment: thorium dioxide reducion.pdf (134kB)
This file has been downloaded 228 times


Dan Vizine - 27-1-2015 at 19:57

Thanks, analog. If you look earlier in the thread I'm following a method developed by Westinghouse for the AEC or whatever the acronym in use in the 40's was.

Your contribution looks great! If the few sentences that I read are really the case, this beats my existing prep. My Na is only 99% but the impurity is probably just other group 1 metals.

The boiling point of pure Na metal is 892 C.

The temp is marginally lower, the reaction time is markedly shorter. It complicates the hydrolysis step a lot, re. H2 liberated, possible dispersion of finely divided Th powder.

I don't see any particular reason that I couldn't start with 99% 2-PrOH, proceed to 70% 2-PrOH and then to water before proceeding to mild nitric acid washes, more water, more 99% PrOH, then acetone.

I tried for the melted chunks, VAR, but nobody is willing to contaminate their machine.

[Edited on 28-1-2015 by Dan Vizine]

j_sum1 - 27-1-2015 at 20:08

Quote: Originally posted by MrHomeScientist  
While I normally avoid powders, I'd make an exception here knowing the extreme time and effort you put into making this product. Sign me up for a sample when it's finally finished! Really great work here.

Ditto.

Dan Vizine - 28-1-2015 at 18:12

Quote: Originally posted by anolog  
The most efficient method to produce thorium metal is reducing the thorium dioxide with combined powder of an alkali metal and an alkaline earth halide.....


entropy,

So, your very first post has turned out to be a real splash...It's potentially going to change the very nature of a project I started early last year.

I LOVE the idea of milling while reacting, and the high expected fluidity at temperature! The inclined configuration is genius. One way or another, that will be used.

I'm really fond of the possibly lower temperature range and of the potentially somewhat shorter reaction period.

But, I'm wary of the excess Na hydrolysis...it's about on par with my worries about trying to distill the sodium off first. That requires construction of another air-tight metal device.

I was already a bit concerned about just the simple calcium hydrolysis. Naturally, not about the hydrolysis itself, but because it combines lots of evolved gas with powdered alpha emitters. I guess that the alcohols will tame the rate. But, that's got it's own complications...

And finally, most chemists realize that while some patents are pretty good, some leave out crucial details and some are almost lies. This doesn't appear to probably one of the last two options. But you never know.

So many new things to ponder and a little math. Want to get j_sum1's sample right.



[Edited on 29-1-2015 by Dan Vizine]

Dan Vizine - 31-1-2015 at 13:31

The preferred route leads to this overall transformation:

2.05 CaCl2 + 4.43Na + 0.411 ThO2 --> 0.411 Th + 0.822 CaO + 1.64 NaCl + 1.23CaCl2 + 2.79 Na

That includes 2.5 X the number of moles of CaCl2 and 2.7 X the number of moles of Na needed stoichiometrically.

The weights of reactants for my 108.5 g of ThO2are:
227.7g of CaCl2
101.9 g Na
for a total mass of roughly 438.1 g.

That leaves a metal/salt mixture containing 64.1 g of Na to hydrolyze while keeping the temperature and air-exposure low and controlling the particulate flow within that stream to avoid aerosols.

Physical removal of solidified reaction mixture from my vessel will essentially be impossible, meaning the "hydrolyze in place" technique needs to be used. The volume of potentially Th-laden hydrogen ought to be about a little over 30 L.

I could try to just distill the excess sodium off. It's about like distilling cesium except with different geometries for the "condenser".

But the main hitch to this is the volume of reactants and products. It really necessitates several runs. Since I anticipate that the reactor will be at or near its limits (per earlier discussion with rep from SS company), each re-run will require a lot of clean-up.

Yeah, I also know that I appear to want to violate the smart way to do things where you do scouting runs, identify your chosen method, then do scale-up. Truth is, I do want to violate it. That's why I've been trying to examine every avenue, every way it can fail, etc. I want to perform the reaction in, as close as I can come to, 1 time.

Also, because we're not talking about a complex, or simply expensive organic reactant, the Th isn't going anywhere if this reduction fails to live up to expectations. If the product isn't exactly what I want, the logical fall-back is to convert any thorium/thoria to the fluoride and go that route, or more likely, re-react it with more Na and calcium chloride.

So, minimizing exposure and producing the best quality product seem to be at odds with one another. Isn't that a shocker?

These issues in no way diminish my appreciation for the new posting. It's great, but how well I can adapt my available resources to it is uncertain.
Rotation of the tilted reactor is inspired*, although I do need to make a leak-tight gas swivel to apply argon to the end of the revolving tube from the reactor. My planned approach is to use a long, slender lubricated hypodermic needle piercing a rubber stopper along its axis.

Since it was mentioned a while back, my reactor has a volume of 11 cubic inches (about 180 mL to those of you almost anywhere else in the world who are not still mired in the English system).

* Almost all synthetic chemists look at unstirred reaction mixtures as being highly suspect, with good reason usually.

[Edited on 31-1-2015 by Dan Vizine]

Dan Vizine - 20-5-2015 at 12:16

Well, I was relieved to note that the only reason that the Na method was used was economy. They just generated the Ca in situ because of the high cost of Ca metal. The reaction is still just the calciothermic reduction of the oxide. I may increase the molar proportion of Ca to improve the product.

Did you think I'd been swallowed by the earth? I was, in a way. That's what traveling constantly feels like.

So, I'm over budget and behind schedule. SNAFU in the literal sense.

But summer is here, outside work is possible and only two more trips (that I know of) stand between me and time for Th.

[Edited on 20-5-2015 by Dan Vizine]

blogfast25 - 20-5-2015 at 12:36

Still, good to have you back! :)

Dan Vizine - 7-6-2015 at 16:13

Thanks....now....I'm in Wisconsin....so, that's another week.

Well, anyway it's set. The reaction will employ a larger than normal Ca/ThO2 ratio, in an inclined SS 309 reactor (~20 - 25 degrees from vertical) which will be slowly rotated, with a few large lumps of SS 309 in the mixture to stir it, for the required time at a minimum of 900 - 950 C under a 5 in Hg pressure of argon. The cooled reactor will be rigorously cleaned of scale and wire wheel brushed/ sanded to a clean metal surface in preparation for in in situ hydrolysis. The 1/4" pipe and the 1/4-to-1/2" adapter will be removed under argon. OK, here's where it becomes tricky. How best to do it?

As a first solution, I'm thinking this is glovebag work under argon with a respirator for good measure. But you know how glovebags never totally seal at the open end? I'll heat seal this open end shut along its entire length. This project has really boiled down to meeting one engineering problem after another. It's time consuming.

blogfast25 - 7-6-2015 at 18:23

Quote: Originally posted by Dan Vizine  
This project has really boiled down to meeting one engineering problem after another. It's time consuming.


This explains adequately why there's only one Dan Vizine! :D

Dan Vizine - 2-7-2015 at 17:38

I think that sounded very complimentary, my friend, thanks! I have weeks of solid travel ahead (at least I'll get to check off another National Lab, Argonne, this time).

But, I've managed to spend some time redesigning the apparatus into it's final form. The scavenging of a discarded stirring motor spurred this. Now the reaction can truly be stirred. That warms and reassures me.

Now, this is just a mock-up to see if the stirring motor was up to the task, and it is. The final reaction set-up will be a bit more substantial and outside.


Thorium set-up.jpg - 231kB

[Edited on 3-7-2015 by Dan Vizine]

blogfast25 - 2-7-2015 at 18:47

Lookin' good. Can't wait for the final push...

Dan Vizine - 10-8-2015 at 17:37

OK....I'm on vacation, after traveling most of the friggin' summer.

Time for this to come together. Proof of my sincerity is evidenced by the fact that I lugged that #&^%$*165 pound tank up 11 cellar stairs with no railings and followed that up with the vacuum pump. The second picture shows the rotating vacuum/gas seal I devised. It's a 2-way valve arranged to deliver either vacuum or argon to the reactor through a syringe needle inserted down the central axis of a rubber stopper and lubricated with silicone oil.

Just need final leak testing, a possible dummy reaction with a SS reactor containing molten calcium (would hate to have intragranular attack, failure, and an ensuing Ca fire loaded with Th), whipping up a 5 in Hg bubbler and this can start.

2015-08-10 21.20.30.jpg - 887kB2015-08-10 21.20.56.jpg - 803kB

j_sum1 - 10-8-2015 at 17:58

I can't wait!

blogfast25 - 10-8-2015 at 18:01

Quote: Originally posted by j_sum1  
I can't wait!


Totally seconded.

Dan Vizine - 20-9-2015 at 11:27

Well, the dummy reaction with only 20 g Ca and 20 g CaCl2 in a 304 SS bomb is currently stirring at 950 - 960 C. After an hour or so, I'll cool the reactor and see just exactly what to expect during hydrolysis.

This gave me a chance to see what, if anything, is problematic before the real thing.

Incidentally, I solved the "time" issue which has kept me out of circulation so much. I gave 6 months notice this week. Plenty of time for them to find a replacement and have me train that person. I'm done with the soul-crushing grind.

2015-09-20 15.17.53.jpg - 2.3MB

[Edited on 20-9-2015 by Dan Vizine]

Dan Vizine - 20-9-2015 at 14:23

The trial reaction was largely uneventful, it revealed one weakness in the setup which was solved by a small piece of silica board.

The pictures show how the SS 304 reactor fared both immediately post-reaction and after clean-up with a 7" SS wire wheel. Not bad, actually, better than I expected.

I'll try the hydrolysis of the Ca/CaO/CaCl2 mixture as soon as I get a chance. It will be interesting to see how easily the top threads unscrew, perhaps giving some indication of the gas-tightness at elevated temperatures.

post reaction.jpg - 1.3MBcleaned.jpg - 824kB

blogfast25 - 20-9-2015 at 14:36

Quote: Originally posted by Dan Vizine  
I'm done with the soul-crushing grind.





Self-employment or massive lottery win?

Dan Vizine - 20-9-2015 at 15:42

Combination of many factors.
I'm old enough, I'll be 63 in a couple months.
Our mortgage will be paid off in 8 months, yearly expenditures drop by $8-9 k.
Three of my closest friends for >40 years have died within the past year. That can focus your values and choices quite profoundly.
I can just make and sell whatever I want (tax free up to, like, $15k). If I sell $6k per year, on top of SS, I'll have the same income as now, but with the mortgage thing, lower bills. I'll enjoy what I do, have time, which is much more valuable than money, and have no boss but myself.

A true no-brainer. My job currently has no end, it consumes all my time. I'm often still answering e-mails at midnight. No, thanks. Not for me.

[Edited on 20-9-2015 by Dan Vizine]

Dan Vizine - 22-9-2015 at 07:33

I've been giving some thought to the "hydrolysis in place" step, which is next. My original plan was cleaning the reactor, post reaction, placing in a large beaker and surrounding by and eventually submerging under ice-water. This has all kinds of obvious down sides and it's abandoned.

I'm now thinking of a deep plastic funnel (or similar) adapted to screw into the reactor. The reactor can still be ice-cooled. and by adding an exhaust line to the upper wall of the funnel and a lid, I should keep mist from carrying off too many fine suspended particles. Perhaps a HEPA filter in the funnel lid? I'd love to find a consumer product which could be repurposed for this part.

This is actually where things become tricky, all the solution processing. This is also where I considered buying a Geiger counter. Units start at a hundred or two. The problem is that they aren't all that good for alpha particles. Counters that are really good for alpha particles have large, special detectors and the units are typically $1500 to $2000. So, back to relying on favorable engineering, I guess.

I suppose equipping my respirators with HEPA filters would be in order, too.

[Edited on 22-9-2015 by Dan Vizine]

Dan Vizine - 24-9-2015 at 07:51

The hydrolysis step appears to be easier than anticipated. The reactor was fitted with a plastic funnel, cooled in an ice-bath and 3 x 80 mL H2O was added in a thin stream. Each time, the reaction was allowed to proceed until the slurry seen in the funnel stem became too thick to allow gas out easily. This slurry was collected in a 1 L beaker. The next portion of H2O was added, etc. A smell was noticed. It could be from a gas or a microscopic mist. I think this should be enclosed when being done and a long period allowed for all possible mist to settle out.

Shown are a few seconds of hydrolysis 1 and pictures of #1, #2 and #3 which show decreasing reaction rates.

Attachment: 2015-09-24 10.28.23.mp4 (7.7MB)
This file has been downloaded 383 times hydrolysis (1).jpg - 225kB hydrolysis (2).jpg - 182kB hydrolysis (3).jpg - 221kB

[Edited on 24-9-2015 by Dan Vizine]

Dan Vizine - 2-10-2015 at 07:07

A couple things learned in the trial run w/o ThO2:

a) The Ca(OH)2 formed is a real nuisance. Now I understand what was implicit in the patents, that it is not dissolved away (solubility = 1.7 g/L @ 20 C), but rather poured of with the supernatant liquid. This explains why the thorium is obtained in two forms, heavy grains which settle much faster than Ca(OH)2 and in the form of "fines" which are decanted off with much of the un-dissolved Ca(OH)2. This is a further handling/isolation issue to address once the majority of the Th is recovered.

b) The presence of oxidation on the 1/4" NPT threads of the pipe which screwed into the reactor indicates some oxygen diffusion. This led to two decisions. The first will be the inclusion of a minimum practical amount of a 2600 F nickel platelet/graphite anti-seize lubricant on the outer 1/2 of the threads. The second has to do with the 1/4" NPT to 1/2" NPT bushing used for the intended reactor. The bushing is rust-resistant steel, not stainless. I want it gone. So, I cut the 1/4" male NPT threaded end off of where I welded it to the pipe, and used a 1/4" NPT pipe die to cut threads in it. I had a solid 1/2" NPT 316 SS pipe plug, with very high quality threads. I bored a concentric hole through the middle and will thread this with a 1/4" NPT tap. After very tightly screwing this together, it will be welded all the way around with Weldmold 880 (a superb welding rod, about 8 to 10 times the cost of SS rods, but what an incredible performer!). This weld won't come in contact with the reaction mixture, so the high alloy content won't worry me.

I have very nearly addressed every single mechanical aspect of doing the reduction cleanly.

One thing I wonder about, though. Since both the Ca and the Ca(Cl)2 will be molten, and the reactor will be turning at an angle and contains 3 large Macadamia nut sized 309 SS lumps for stirring, why are Ca shavings and powdered Ca(Cl)2 needed? It would be preferable, from the standpoint of moisture exclusion, to add cleaned Ca lumps and fused pieces of Ca(Cl)2 directly to the reactor. The mild "ball-milling" which will take place ought to homogenize the reaction mixture. Any thoughts on why this may not be desirable?

j_sum1 - 2-10-2015 at 16:40

I can't think of any reason why you need to use powder/granules if the result is liquid.

I am vicariously loving this saga. Thanks for keeping us informed even though not many of us are able to contribute much.

Dan Vizine - 6-10-2015 at 18:40

Well, a few mundane but useful facts were learned:

a) Complete work-up of the blank, run in SS 304, gave only a few milligrams of insoluble gray material (perhaps too small to even collect and weigh). This bodes well for minimal metallic impurities in the product.

b) Without a thread sealant, no amount of torque can seal the threads entirely gas-tight. My one concern is the hydrocarbon and graphite that will burn off the sealant and cause minimal C contamination of the Th. If that's the case, it still greatly beats O2 contamination.

c) I used 1.5 times the specified amount of dilute HNO3 to dissolve all of the Ca (OH)2. If some Th is lost, it will be (recovered) worth it to avoid solid-bearing mists from high speed agitation.

Re-made.jpg - 468kB

Fulmen - 7-10-2015 at 05:38

Quote: Originally posted by Dan Vizine  

b) Without a thread sealant, no amount of torque can seal the threads entirely gas-tight

Not surprising. Even though NPT are considered fluid-tight it requires exceptional tolerances or that one part can yield. If a sealant isn't desirable a gasket or crush washer between the two nuts should work.

Dan Vizine - 7-10-2015 at 10:09

I've thought about those options, but I didn't have any bright ideas on what to use.

That area will be in air for a minimum of 1 hour, and ideally several hours, at something approaching 1000 C. That rules out so many options that it's ridiculous.

And given that it needs to be soft enough to deform sufficiently to become gas-tight....tough nut to crack.

I think very, very thin platinum foil could work as a Teflon tape substitute, something along the lines of cheap brands of aluminum foil.

The other sealant I considered was MoS2. It has a very high mp but the literature says:
Ambient Temperature Range -185 to 350 ºC
Vacuum Temperature Range -185 to 1100°C at 10-14 Torr
So, it may not be the best option.

The graphite/nickel platelet formulation claims a 2600 F rating. I plan a few experiments where I put the mix on male threads, bake it at different temperatures, and compare the sealing properties of the baked mixture with the normally applied paste.

Fulmen - 7-10-2015 at 19:37

That is some serious conditions, bro. But does it have to be completely oxidation proof? Only the outer surface will oxidize, so as long as it's diameter is large some loss shouldn't affect the seal. And any oxygen leaking through the mating surfaces would oxidize the material, wouldn't this produce an increase in volume that could cause it to be self sealing. Not sure if that would work, but it's worth some consideration.

One other problem with a gasket like this is the thermal expansion, if it is different from the vessel it could cause problems either during heating or subsequent cooling. So a thin gasket would probably be the safest option.

Dan Vizine - 27-7-2016 at 19:35

Tomorrow.

2016-07-27 20.41.35.jpg - 2.2MB

violet sin - 27-7-2016 at 19:37

YAYYY!!! Such a fun project to follow :) thanks for sharing

Thorium production moved to Radiochem.

Dan Vizine - 27-7-2016 at 19:42

This move was surprising, in that radiochemistry is merely one of the characteristics of the desired product. This is a synthesis topic. Always has been.

And it will happen tomorrow.
http://www.sciencemadness.org/talk/viewthread.php?tid=29927&...

2016-07-27 20.41.35.jpg - 2.2MB

j_sum1 - 27-7-2016 at 19:48

Agreed. Surprising. Following this I think that the major challenges have been engineering ones to cope with the extreme nature of the chemistry involved. It makes as much sense to put it in technochemistry as it does in radiochemistry.


(Shouldn't this thread be in Forum Matters? :P)

Texium (zts16) - 27-7-2016 at 20:01

Sorry, I moved it without thinking much of it. I'll put it back in Chemistry in general and merge this to it. No problem.

Dan Vizine - 28-7-2016 at 10:25

Thank you, zts 16.

And now, on with the show.

I'll prepare a detailed write-up to accompany this prep.

For now, here are some visuals:
https://www.dropbox.com/s/w7p1lr0m47dduky/Start%20of%20Th%20...

This is a short clip of the start of the reduction (initial heating).

I'm now at 950 C (2:20 PM).

2016-07-28 13.37.38.jpg - 3MB

blogfast25 - 28-7-2016 at 14:19

Dan:

Tell me again what is the purpose of the inclination?

Dan Vizine - 29-7-2016 at 10:49

Quote: Originally posted by blogfast25  
Dan:

Tell me again what is the purpose of the inclination?


It's to achieve good mixing. If it were vertical, stirring wouldn't be as good. The original workers milled their charges to get a homogeneous mixture. That wasn't easy, practical or safe for me.

Dan Vizine - 29-7-2016 at 11:12

Quote: Originally posted by Fulmen  
That is some serious conditions, bro. But does it have to be completely oxidation proof? Only the outer surface will oxidize, so as long as it's diameter is large some loss shouldn't affect the seal. And any oxygen leaking through the mating surfaces would oxidize the material, wouldn't this produce an increase in volume that could cause it to be self sealing. Not sure if that would work, but it's worth some consideration.

One other problem with a gasket like this is the thermal expansion, if it is different from the vessel it could cause problems either during heating or subsequent cooling. So a thin gasket would probably be the safest option.


A practical metal gasket for threaded connectors? I didn't know they existed. Funny you should mention oxidation though..."heat-resistant" SS 308 seemed to fare far worse at 950 C than the SS 304 that I usually use. That forms a tightly adherent scale, this eroded away layer by layer. I was certain that I had a reactor breach upon first sight. I'm still inspecting and cleaning the reactor and struggling greatly to unscrew the connecting pipe.

1.jpg - 131kB 3 (2).jpg - 175kB 3 (1).jpg - 116kB

[Edited on 29-7-2016 by Dan Vizine]

blogfast25 - 29-7-2016 at 16:43

@Dan:

Thought as much. Thanks and good luck!

Dan Vizine - 29-7-2016 at 17:22

I cleaned thing things up in preparation for hydrolysis in place. Mostly okay, but one area is slightly suspicious. Still assessing. Yes, I know this is glacial. Sorry, but it is progressing....

4.jpg - 2.2MB5.jpg - 2MB6.jpg - 1.8MB

Dan Vizine - 30-7-2016 at 11:46

The 1/2" threaded connection yielded to a pipe vise and a 24" pipe wrench.

The reactor was prepared for the "in-place" hydrolysis by thoroughly isolating the reactor's exterior to prevent sloughing off of impurities during submersion. Theoretically the interior should be quite clean.

2016-07-30 15.27.19.jpg - 1.2MB

Dan Vizine - 30-7-2016 at 15:18

The interior, what I could see of it, was clean. Hydrolysis was performed as per 9-24-15 trial run, but under a sophisticated cover - a clear acrylic wastepaper basket with a 1/8" hole in the top, er, bottom...you know what I mean, for drop-wise distilled water addition. I'm eating spaghetti, it's ever so slightly effervescing. Tomorrow morning I'll pour it out....

Dan Vizine - 31-7-2016 at 11:32

Well, it's done...or getting there. But there's the thorium.....

2016-07-31 15.19.30.jpg - 628kB

NEMO-Chemistry - 1-8-2016 at 02:49

Extraordinary thread, just finished reading it all. Bit like a decent book in places, a few twists and turns 'would he bottle it or would he not'.

No idea how dangerous that stuff is but i got the impression its not something to be messed with, so seeing a jar held aloft by hand at the end............I thought 'now thats what you call a utterly MAD scientist!!

I am fully expecting you to be supplying your neighbours next year with self generated nuclear power.

Well done its beyond impressive which ever way you look at it. Why does everything great always look like sludge? Only stuff like sodium chloride seems to look pristine white and fluffy.

Dan Vizine - 1-8-2016 at 11:22

I had the same thought, it's a bit anticlimactic to look at.

Thorium is like most primarily alpha emitters. Essentially harmless in the sense that alpha particles don't penetrate skin. But ingested or inhaled alpha emitters are super dangerous, see polonium, plutonium.

Now, on to the final isolation...


[Edited on 2-8-2016 by Dan Vizine]

NEMO-Chemistry - 1-8-2016 at 12:08

Quote: Originally posted by Dan Vizine  
I had the same thought, it's a bit anticlimactic to look at.

Thorium is like most primarily alpha emitters. Essentially harmless in the sense that alpha particles don't penetrate skin. But ingested or inhaled alpha emitters with long half-lives are super dangerous, see plutonium.

Now, on to the final isolation...



[Edited on 1-8-2016 by Dan Vizine]


Must be deeply satisfying though after all the effort to finally get your crude product.

Well done its a really inspiring read.

Dan Vizine - 1-8-2016 at 12:36


Thank you most sincerely.

The story isn't over by a fair stretch. A good write up needs to be done, all info. in one succinct spot. Anomalies (there was one, as hinted at by the reactor's bottom edge) need analysis. Spoiler..it seems to have been rather benign. And the final product isn't a final product until fully processed, washed, dried, passivated & bottled.

Yes, satisfying and a relief. So many man-hours, so much labor and more than a few $$ were involved. I even built the furnace for this project. The tank of UHP argon was $140, the tig welding was $140, the chemicals were over $800, misc. materials were another $50. Way, way over 100 man-hours all things considered. Perhaps 200.



[Edited on 1-8-2016 by Dan Vizine]

j_sum1 - 1-8-2016 at 15:56

Congratulations Dan. This has been a monumental effort and your results have been hard-won.

Is it my imagination or is your holding of that jar a posture of triumph?

I am looking forward to a write-up but in the meantime I must set aside some time to re-read this whole thread.
I presume the write-up will go in prepub?

Magpie - 1-8-2016 at 16:07

Nice going Dan. ;)

I know what you mean about some of these obsessions costing a lot of money. My autoclave construction comes to mind, ~$550. My homemade hood ran about $2000.

But it is sweet to be at a point in one's life when you have the option of taking on these projects. And the man hours? That's all just fun!

[Edited on 2-8-2016 by Magpie]

Dan Vizine - 1-8-2016 at 18:28

After 3 re-suspensions in 1.5 L distilled water (fines decanted off include calcium hydroxide and very fine thorium particles)....

On to dilute nitric acid washes.

Thorium.jpg - 190kB

Dan Vizine - 2-8-2016 at 15:46

First wash with 1 L (Distilled H2O - HNO3) (8:1) shows a distinct darkening as residual Ca impurities are dissolved.

HNO3 wash 1.jpg - 866kB

Dan Vizine - 3-8-2016 at 15:54

Subsequent washes, washing time, settling time before decantation

1.0 L DI H20 3 hours 10 min.
1.0 L (DI H2O - HNO3) (8:1) 8 hours 10 min.
6 x 1.0 L DI H2O 1 hour 5 minutes

Settling: https://www.dropbox.com/s/4khwojlye381a80/2016-08-03%2019.34...

Attached pics show final supernatant H2O and comparison of pH of this liquid and the virgin DI H2O. I can't see a difference. Final washes and drying tomorrow.



2016-08-03 19.35.59.jpg - 2.2MB 2016-08-03 19.38.52.jpg - 206kB

[Edited on 3-8-2016 by Dan Vizine]

Dan Vizine - 6-8-2016 at 13:17

THE PREPARATION OF PURE THORIUM METAL BY THE SYLVANIA PROCESS


1. Th(NO3)4 (H2O)4 + NH4OH ---> Th(OH)4 ------>ThO2


2. ThO2 + Ca ------> Th


Anhydrous thorium dioxide (1)

To a stirred, clarified, room-temperature solution of thorium nitrate tetrahydrate (227 g, 411 mmol) in distilled H2O (2.5 L) was added 28% aqueous NH3 (317 mL, 285 g, 4.60 mol) in one portion. The temperature of the resultant white slurry was found to rise slightly (~35 C). Stirring was continued under ambient conditions for 1.0 h and then the precipitate was collected by filtration and washed in succession with distilled H2O (3 x 500 mL), dilute aqueous NH3 (0.6 M, 5 x 500 ml) (note 1) and additional distilled H2O (5 x 500 mL) to give crude thorium hydroxide (note 2). The extremely bulky bright white solid was air-dried to give a dense, friable off-white solid of approximately 15 - 20% of its original volume. After drying to constant weight at 80 - 90 degrees C for 15 h, the solid was pulverized to give127 g (103 %, TY= 123 g) of a very heavy white powder. The excess weight is residual water and ammonium nitrate. Calcining in a 2 inch diameter Mullite tube, with one closed end and the other end vented to the atmosphere, was started. At about 400 C, a small amount of brown gas was seen, supporting the presence of a small amount of ammonium nitrate. The colored gas disappeared after 10 minutes and water vapor was noted to be evolving slowly . After a total of 12 hours at 1000 C, the material was recovered from the process tube and finely ground with a mortar and pestle. The resulting off-white, heavy powder was packaged under argon to give 108 g (99.5%, T.Y. = 108.5 g) of anhydrous thorium dioxide (1).

Thorium metal (2)

A full-penetration TIG-welded SS 309 reactor (2 in dia., 4 in long, 0.125 walls) fitted with machine-cut female1/2" NPT threads on the top surface was inerted with UHP argon and then charged with (1) (87.5 g, 331 mmol), anhydrous CaCl2 (35 g), and high-purity Ca (99.9%) filings (34.5 g, 861 mmol). The reactor was immediately closed (note 3) with a male 1/2" machine cut NPT threaded adapter that transitions to 1/4 " SS 304 pipe 10 inches long terminated with a SS 316 Swagelok valve. The reactor was supported at an angle of ~15 degrees off the vertical, inside of an electrically heated oven, and slowly rotated by the pipe/valve (note 4) which was attached to a SS 316 7 micron in-line filter and then to an axially mounted, new 00 rubber stopper. The rubber stopper was pierced down its axis by a silicone grease-lubricated syringe needle (4 in length, 14 gauge) which connected to a three-way valve which allowed for its routing to either a mechanical vacuum pump or UHP argon (supplied at a pressure of 5 inches Hg using a bubbler). In operation, the lubricated stopper revolves around the syringe needle creating a rotating gas-tight seal. The reactor valve was opened and a series of six evacuation/refill cycles was performed. The oven was heated to 950 C over an hour and stirred for an additional 5 hours under the UHP argon at 5 in. Hg. The heating was stopped, the reactor valve was closed and the reactor was separated from the upstream components and cooled. The reactor exhibited heavy scaling (note 5). After exterior cleaning and inspection the reactor was opened, fitted with a threaded-to-fit plastic funnel and put into a ice-water bath under an inverted acrylic dome (note 6). Water (~ 150 mL) was added, dropwise at first, to the reactor. The presence of unreacted calcium was confirmed by hissing and bubbling. After two hours, the reactor's contents were emptied into a large glass reactor (1 gal bottle). A rinse, close, shake, open and empty sequence was repeated 8 times on the reactor by which point inspection revealed it to be empty. The closed glass reactor's contents were mechanically stirred for 18 hours and then allowed to settle for 5 minutes. All suspended solids were then removed by decantation. A further 3 re-suspensions in 1.5 L distilled water, decanting off the suspended solids in-between, were performed. The solids were then stirred with 1 L (distilled H2O - HNO3) (8:1), recovered by decantation after 5 minutes, then the process was repeated with 1.0 L distilled H20 for 3 hours followed by a 10 min. settling, 1.0 L (distilled H2O - HNO3) (8:1) for 8 hours followed by a 10 min.settling, and finally with six identical 1.0 L distilled water washes for 1 hour with 5 minute settling periods. The final aqueous decantate had a pH identical to the original distilled H2O and was totally transparent and colorless. The solids were collected by filtration, washed in succession (under argon) with acetone (3 x 300 mL) and petroleum ether (30 - 60 degree) (3 x 300 mL) then dried to constant weight in vacuo for 18 hours to give (2) as a heavy gray powder (63.0 g, 82.0%, T.Y. = 76.8 g)




Notes

1. Prepared by dilution of 103 mL 28% aqueous NH3 to a volume of 2.5 L with distilled H2O.

2. The solid is also referred to as ThO2 dihydrate in some sources.

3. Vibra-TITE compound, nickel platelets in a graphitic base, rated for 2600 F service

4. The valve was connected to the hollow shaft of a stirring motor which was then attached to the in-line filter and 00 stopper.

5. A few grams of a material resembling gray stone was recovered from the furnace floor. Upon standing in 25 mL H2O overnight it disintegrated into a mixture of a white precipitate and gray flakes. The pH was quite basic. The postulated cause is a pin-hole leak at the reactor floor allowing a tiny amount of molten Ca/CaCl2 to push through it under the argon pressure and dislodge some of the scale from the reactor exterior. The utterly pristine, silver colored metal surfaces inside the cooled reactor are good evidence for no significant back-diffusion of oxygen.

6. A clear plastic waste basket about 1.5 feet tall and a foot in diameter with a 1/8" inch hole drilled in the center bottom.


2016-08-06 16.30.10.jpg - 374kB

[Edited on 6-8-2016 by Dan Vizine]

Magpie - 6-8-2016 at 14:33

Very nice work on such a challenging project.

1. What are machine cut NPT threads? Is this something you did or did you hire this out? In my experience it is next to impossible to get NPT threads gas tight. Why did you choose NPT? Wouldn't some type of fine thread be easier to seal. But since your reactor is vented anyway maybe this makes no difference?

2. 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).


Dan Vizine - 6-8-2016 at 15:56

Quote: Originally posted by Magpie  
Very nice work on such a challenging project.

Thanks!

1. What are machine cut NPT threads? Is this something you did or did you hire this out? In my experience it is next to impossible to get NPT threads gas tight. Why did you choose NPT? Wouldn't some type of fine thread be easier to seal. But since your reactor is vented anyway maybe this makes no difference?

Threads can be rolled between flat dies (exterior ones, anyway) or cut by taps and dies. For example, nearly all machine bolts are rolled, not cut. Threads show so much variation. The ones I used were visually perfect, smooth, deep and sharp. NPT was designed to be gas or water tight when used with a thread sealant. The main valve of gas cylinders are always NPT, connections to regulators are 1/4" NPT, etc. The trick is holding integrity at temperatures that decompose these sealants.
A fine NPT thread designed for 6000 PSI service is made but they weren't pursued on availability grounds. I wanted absolutely no leaks, that's why I hired a professional welder. The vessel was leak tested at 100 PSI under water and showed no leaks. But this reactor was being used at its limit and molten Ca/CaCl2 is aggressive. The 2.5 PSI pressure probably pushed the molten material along a weak spot, grain boundary, partial pinhole or whatever. As it emerged it hardened as CaO limiting further leakage. Maybe. Or maybe it had just started as the reaction finished. Hard to say. The nickel/graphite sealant performed well. Notice how clean the end of the threads are, the atmosphere was argon with little or no oxygen.


2. 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).

I consider myself a moderately skilled welder. But, I COULD NOT weld a leak-free SS vessel. Despite grinding out bad spots and re-welding 4 or 5 times, leaks always persisted. When I told this to the professional welder he said that is not surprising at all. He said it is generally impossible to do with an AC stick welder.

Sometimes the leaks in my welds didn't appear until the interior pressure reached a couple atmospheres, but they ultimately always did.



2016-08-05 23.20.06.jpg - 992kB

Bezaleel - 6-8-2016 at 18:07

Congratulations, Dan! Great work in the engineering part in particular.
Do you plan to continue on a follow-up project of melting your Th into a single lump? (MP = 2023 K ​(1750 °C))

Quote: Originally posted by Magpie  
Very nice work on such a challenging project.

1. What are machine cut NPT threads? Is this something you did or did you hire this out? In my experience it is next to impossible to get NPT threads gas tight. Why did you choose NPT? Wouldn't some type of fine thread be easier to seal. But since your reactor is vented anyway maybe this makes no difference?

2. 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).


I supposed Machine Cut as opposed to Die Cut. However, on pg. 7 Dan mentions Precision Cut as opposed to Rolled. Wouldn't even consider using a rolled thread for a purpose like this, so yes. Rolled threads are good when it comes to mechanical strength, but not when it comes to precision fitting, as required in this case.

One thing I wonder about is why no copper flange gasket has been used instead of a precision thread, but probably the operating temperature is too close to the melting point of copper (1084.62 °C per Wiki).

Dan Vizine - 6-8-2016 at 18:56

Thanks Bezaleel.

Yes, you're right, Die-cut may be what the lower quality NPT threads are. I'm really no expert, but the threads on the LHS are visibly superior to those on the RHS.

The reason for not using flanges is as simple as cost. Precise flanges would require welds but then machining to eliminate warping caused by welding. Copper could have been usable at 950 C if thin stock was used.

There are so many things that COULD be done....
An inert-atmosphere furnace
Induction heating
Specialty crucibles like Mo (in inert atmospheres)

In any case, I think one metric by which we could say this was sufficiently protected is that the Th doesn't blacken in air readily. This usually signifies a purity in excess of 99%.

I cannot find an arc-furnace operator interested in contaminating his chamber with thorium. I obviously can melt it here, but not without destroying it in the process. That only leaves pressing as an option. That's a poor option with this powder, without real precision tooling, which I don't possess. Thus, the contamination possibility is unacceptable.



Threads.jpg - 787kB

[Edited on 7-8-2016 by Dan Vizine]

Dan Vizine - 7-8-2016 at 08:35

The Dropbox link to the above-referenced clip has been deleted.

Instead, here is a Dropbox link to all of the sources, pictures and movies that I accumulated over the course of this project. It's over 300 MB. The link will be good for several months. Please download anything that you might want to save.

https://www.dropbox.com/sh/ev4astc7zikpy7k/AADj3Pu4eanMDuTbW...

And this link is a chronological ordering of the most important pictures. Each picture is titled by a description of what it's about :

https://www.dropbox.com/sh/5mjwdsnm0mhs7r2/AABCONsCnSInHQRFD...


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

Dan Vizine - 10-8-2016 at 13:30

Sometimes it's easy to overlook things you take for granted.

Say, for instance, the above calciothermic reaction. The temperature controller said that the furnace temp. was ~ 950 C. The color of the reactor says something different. It's yellow to my color-challenged eyes. This suggests why the pinhole leak make have happened. This steel was at 1200+ C and being pushed to its limits.

So, the placement of the thermocouple wasn't as good as it could have been. But perhaps that's part of the reason for the thorium having apparently very low ThO2 content (judging, again, from resistance to darkening in air).

Temp of reactor.jpg - 92kB

NEMO-Chemistry - 11-8-2016 at 09:49

Finally a product that dosnt resemble crud!! Superb read and work!! A real challenge and some fabulous engineering.

I found the whole thread totally inspiring, not that i am ever likely to be good enough to even contemplate something like this, i think the mere fact it was done outside of a special laboratory makes it special.

Dunno how others feel or view it, but personally i think projects like this prove amateur science projects have a place still within society.

It shows even the most challenging projects can be done by in non professional settings safely, as long as the project is handled in a professional such as this one was.

Getting a thorium sample for a element collection is one thing, but to actually make a sample is on another level, congratulations! And yes i can finally see it :D, i was starting to think you was fobbing me off with green gunk lol

Dan Vizine - 11-8-2016 at 14:37

Quote: Originally posted by NEMO-Chemistry  
Finally a product that dosnt resemble crud!! Superb read and work!! A real challenge and some fabulous engineering.

Thank you NEMO-Chemistry. It had to work. Since I was a chemist by profession, as soon as I ran my mouth off, there was no going back. It was success or utter embarrassment.

I found the whole thread totally inspiring, not that i am ever likely to be good enough to even contemplate something like this, i think the mere fact it was done outside of a special laboratory makes it special.

Don't sell yourself short, I'm a 63 yo fossil. I'm guessing from some of your writing style that you've got decades ahead to gain experience.

Dunno how others feel or view it, but personally i think projects like this prove amateur science projects have a place still within society.

Yes, I agree to a point. But there are limits today that earlier workers didn't have to face. One is that all of the easy stuff has been done already. A new element takes multi-million dollar machines to make, a new drug....forget it... a new synthetic reaction? Better have an NMR. On top of that, chemical companies curtail access to research chemicals more by the year.

Sadly, the days of the basement chemist making a truly new and significant contribution to science are just about over. We can, however, come up with impressive replications of earlier work


It shows even the most challenging projects can be done by in non professional settings safely, as long as the project is handled in a professional such as this one was.

Thanks again. I tried to be as hygienic as possible. I have spent every free moment of the week doing nothing but clean-up. Full-body suits, full face shield, dozens of disposable gloves, aqua regia and also Mn heptoxide rinses, and on and on....
Tonight I'll repaint the garage floor and call it done. My cats can have their garage haunt back


Getting a thorium sample for a element collection is one thing, but to actually make a sample is on another level, congratulations! And yes i can finally see it :D, i was starting to think you was fobbing me off with green gunk lol


The product is really rather beautiful after all the extensive washing. My greatest fear was that the powder would blacken readily, meaning that ThO2 was >1%. Because, if it's more than 1%, I have no way to say it's not %5. The powder is a light steel gray. Acid washing of ThO2-free samples is said to improve purity to 99.6 to 99.8%. I likely have several hundred ppm of both chromium and nickel.

NEMO-Chemistry - 12-8-2016 at 04:20

63! Only the good or very lazy chemists reach that age :D. So i guess you must be good.

Yes i have a way to go before i reach 'old age', although Darwin seems to be constantly on my shoulder :D.

I have started to read up on Marie Curie and others who first started to isolate such metals. Absolutely mind blowing what they did with what i would consider pretty primitive equipment!

Ok Curie paid the price but the work to process vast amounts of ore is mind blowing.

It might be my age but i still live in a bubble that says one day an amateur will discover something significant in his shed, i think without that i would view science differently and maybe loose interest.

But i am still at the nice stage where even the very simple is extremely exciting! Salt from sodium and chlorine reacted in a flask with sand on the bottom still fascinates me (welders mask etc ).

Manganese and changes in oxidation state still amaze me. I am not into big bangs as such, but i am developing an interest in flashes of different colour :D.

Over here things like that get you into alot of trouble, so my ventures with black powder using different oxidizer's is very very small scale and limited.

Loud bangs and blowing things up dosnt really interest me. The Thorium interests me because i am fascinated by cloud chambers and watching the decay process. But thats is all for when i am confident i can keep Darwin at bay.

Dan Vizine - 15-8-2016 at 06:39

Interestingly, although Marie Curie witnessed the premature deaths of several workers in the nascent field of radioactivity, she never admitted that there was a direct connection. She never even acknowledged that there was a relationship between her work and her ultimately radiation-related (my words) death.


Dan Vizine - 23-8-2016 at 13:51

A final close-up.

2016-08-23 17.05.28.jpg - 1.7MB

phlogiston - 23-8-2016 at 15:09

Thanks a lot for sharing the inspiring and captivating story of making this! I can't tell you how much I enjoyed reading about your meticulous planning, problems, solutions and final success with us. Looking at the history of the element, it appears likely that you are the very first -amateur- scientist in the world to isolate this metal in the last century (if not ever, depending on whether you count well-to-do victorians). There ought to be an olympic medal or noble price for amateur chemistry, but alas.

Is the cleaning effort purely precautionary or have you actually detected some contamination?
From the perspective of an interested element collector: are you planning to recover some of the cost by selling some of the metal? (or make a well-deserved profit, I don't care about the financial details, just if you are planning to sell samples of it)

[Edited on 23-8-2016 by phlogiston]

j_sum1 - 23-8-2016 at 15:30

I agree. This has been fascinating to watch. It has been a lot of hard work. Your excellent results are truly well-deserved.


Quote: Originally posted by phlogiston  
From the perspective of an interested element collector: are you planning to recover some of the cost by selling some of the metal? (or make a well-deserved profit, I don't care about the financial details, just if you are planning to sell samples of it)

[Edited on 23-8-2016 by phlogiston]


Actually, I think you deserve to keep every single hard-won microgram to yourself. You have bragging rights over Theo Gray on this one.
(Actually, now that I think about it, it wouldn't hurt to let him know what you have accomplished. I am certain he would be interested and probably enjoy a photo. For thorium, he might even pay a visit.)

But on the off-chance that you are in the sharing mood, I know I would pay good money for two or three sand-sized particles in an ampoule under argon or embedded in glass. I think for my element collection, having a miniscule sample would be testament to the extreme difficulty in obtaining the element.

Dan Vizine - 23-8-2016 at 17:06

That's high praise, thank you!

An eBay seller forwarded me this NRC ruling...(he sells thorium compounds on eBay without too much trouble from his store or "firm")...

As my status as a "commercial firm", simply because I sell items on eBay, is not on firm ground, I won't be selling individual samples to anybody. I'm sorry, but I don't think I'm allowed to sell under these rules.

Ownership of this material was transferred last night to a bona fide commercial firm specializing in element samples. They pay to have it legally shipped to them. They can legally sell natural thorium for purely commercial purposes under the small quantities of source material "General License" rule. This is automatically granted simply by virtue of being one of the below groups, no application needed.

§ 40.22 Small quantities of source material.

(a) A general license is hereby issued authorizing commercial and industrial firms; research, educational, and medical institutions; and Federal, State, and local government agencies to receive, possess, use, and transfer uranium and thorium, in their natural isotopic concentrations and in the form of depleted uranium, for research, development, educational, commercial, or operational purposes in the following forms and quantities:

(1) No more than 1.5 kg (3.3 lb) of uranium and thorium in dispersible forms (e.g., gaseous, liquid, powder, etc.) at any one time.

It wasn't clear from the regulations if private individuals can even possess source materials other than a few specific items, U glass, U & Th ore, tritium signs, the usual suspects.

Once they have packaged it, I'll let the forum know here.

Again, several people expressed interest in samples and I apologize for promises I made before I knew the regulations.

j_sum1 - 23-8-2016 at 17:27

Quote: Originally posted by Dan Vizine  
Ownership of this material was transferred last night to a bona fide commercial firm specializing in element samples.


Wait! does that mean you have done all of that work and not kept any for your own element collection??


I can't see that I would ever have done that. I am not saying I would do like Scrooge McDuck does with gold but -- I would at least admire my work for few weeks.

Dan Vizine - 23-8-2016 at 20:11

No, I didn't. I kept 5 grams. Nobody will bother you for that. They just don't want private individuals selling it, I think most probably because it will be shipped improperly. But other factors come into play. Owners of "source material" may not abandon it. Ever. They must technically ship it in accordance with law to one of four long-term nuclear repositories and pay for disposal. This is the lowest level waste so all four sites accept it.

This law is obviously violated frequently. Dozens of us here have DU. A friend who was selling DU on eBay sent me this message:

I'd be very careful with selling this material on ebay. I'm not sure if I ever told you what happened to me when I was selling DU samples on ebay. A few years ago I was contacted through ebay from someone claiming to be from the MA department of public health radiation control program. They told me to cease all sales of DU. It was very unprofessional and I shrugged it off as someone harassing me on ebay. A few weeks later I got letter in the mail from the same place. It was a cease and desist letter stating that I had to delist all my DU samples. Apparently the NRC had saw them and tipped off the MA DPH radiation control. MA is an NRC agreement state which means they relinquish all regulatory requirements to the state. I took down my listings but they sent me another letter asking for the specs on my storage facility, leak testing, calibration data for my detection equipment, etc. I explained to them that I was just a private citizen at a residence and not a big company. They sent another letter saying that the matter was closed. It didn't end there though. About two months later I was paid a visit from two FBI agents! They started by saying that DU was some pretty serious stuff and asked what I was doing with it. I told them no, it's depleted you can't do much with it at all and I explained how I was selling small samples on ebay to collectors for educational purposes. They started asking me crazy questions like did I support terror, was I a member of isis, did I want to hurt US citizens. I swear it was like something from a movie! Long story short is that the MA DPH said that by selling DU on an online auction site, I can't guarantee that it will end up with someone properly licensed or properly stored. I never heard back from the FBI. They said they were just "checking up" on me because MA DPH was worried. I know ebay seller Hudaho was selling Th foil samples and he was harassed by ebay into taking them down as well. Anyway, just thought I'd warn you, I don't know what the laws are like in your state regarding stuff like that but I don't want anyone to have to go through what I went through. It was just so ridiculous and unbelievable! All over some tiny DU samples.


So, this arrived after the Th was done. I decided to try to do the most cooperative thing and that was get it out of my possession and keep everything within the legal boundaries.

Concerning an earlier question of thorough clean-up, here is part of the complete write-up. Since you can never say nothing is there (thickness of detector window deflects some alphas), it seemed prudent to re-paint the garage floor. What if a drop splashed that I didn't notice? I wet-mopped. The thing about alpha particles, you just need to immobilize trace amounts to make them safe. I didn't find floor areas above background levels but I'm not trained on the instrument. I used the most careful techniques that I could. I'm comfortable with it.

I can't see myself ever repeating this experiment because of the potential for official intervention. If they want to be unsympathetic, it can be a nasty gray area.

__6.jpg - 163kB

j_sum1 - 23-8-2016 at 20:37

Sounds like someone needs to learn what the word, "depleted" means.

I guess that is a reasonable outcome all things considered. And nice that you could get rid of all of your collectable waste in a straightforward fashion.

There is, as always, a double standard here. I can buy 2% thoriated welding rods OTC, burn them up in use, release unknown quantities of Th into the air (more rather than less knowing my welding), catch some in my respirator (or not!) and no one will bat an eyelid. I could even let the rods rust and have the Th enter the environment.

But you, because you are doing some actual science and concentrating the thorium are subject to all kinds of regulations regarding waste as well as the product formed. The safety standards you impose on yourself with respect to cleaning up alpha sources in your garage are far more rigorous than any imposed regulation, and yet for all that, you cannot be trusted to package and distribute in a responsible manner.

Such are the delights of red tape and a litigious society.



For my element collection I intend to buy a welding rod and maybe a lantern mantle (if I can find one). In the short term. In the long term I hope to have a tiny scrap of actual metal. But I won't be making it myself.


violet sin - 24-8-2016 at 00:48

ya unfortunately it looks like you have invested time and effort in creating a road map that will be appealing to those FAR FAR FAR FAR less competent individuals that abound on the internet. Yet you, did all the learning, processing, clean-up in QUITE the respectable manner, and get shafted...

rules is rules, gotta respect them. just a darn shame. guess I am gonna have to make due with my welding rod and mantle for samples. been looking into some mineral specimens to round out the set. but there will be no chem experiments, refining or otherwise. beyond irresponsible with my income, lab space and location( not a whole hearted tragedy, just not a bright idea)

well you learned a lot, have an epic of a tale, bragging rights to the moon and a personal sample for your collection. So the half full side of the chalice is still looking pretty darn good. gotta stay positive :) thanks for a hell-ava journey

NEMO-Chemistry - 24-8-2016 at 05:10

Yeah the bragging rights and pictures are worth a shit load more than some grey powder. Plus if your hit by a bus (I hope not), then no one careless gets to handle it.

Shame you couldnt keep more but having said that, its probably better that way in the long run.

No one can argue you didnt do it, to me what you had to overcome to get it done and the pics of the steps are worth way way more.

I know your a professional but you were not in a multi million £ facility with a open ended budget! So it makes it really special.

I agree about the prize, there really should be some kind of prize for doing stuff like this. My favourite picture is the heat pic showing the hot spot. Every time i look at it i think 'damn that was trying hard to get out'.


SO whats next on the list? I dont see how you can stop now at Thorium :D. Honour dicates you have to top that lol :P. I am only goading you into another fabulous write up but i doubt your going to fall for it.

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