Sciencemadness Discussion Board

Making Old Radium Glow Again?

MyNameIsUnnecessarilyLong - 6-12-2014 at 17:39

I bought this Fitrite radium watch repair kit several years ago just for novelty's sake, but I would now like to make a radioluminescent torch or some kind of display piece from it.



The smaller vial contains a whitish loose powder and the outside of the vial reads about 15k cpm on the geiger counter. It still glows in the dark but is very faint. I presumed the zinc sulfide has degraded over the years so I bought some strontium aluminate glow powder to add. After I added a small amount of aluminate to the vial there was no noticeable increase in glow. Does this mean there is too much old phosphor/binder/filler material present and it's shielding the aluminate from the radium? How much radium was generally included in repair kits? Could it be easily extracted? Would it even be practical to attempt an extract of the radium, or is it present in very minute quantities?

neptunium - 6-12-2014 at 18:02

wow! man where the heck did you dig that lucky find?

MyNameIsUnnecessarilyLong - 6-12-2014 at 18:31

Quote: Originally posted by neptunium  
wow! man where the heck did you dig that lucky find?


Got it off Ebay

But I found this site a few days ago:

http://www.radioactivethings.com/radium-hands-paint-and.html

Looks like they had some pretty interesting things recently, including a 30k cpm vial from the infamous US Radium Corp.


[Edited on 12-7-2014 by MyNameIsUnnecessarilyLong]

careysub - 6-12-2014 at 22:26

Quote: Originally posted by MyNameIsUnnecessarilyLong  
... I presumed the zinc sulfide has degraded over the years


You are correct. Radiological damage occurs to the crystals (which have to be specially prepared to glow brightly) and they stop glowing very much.
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Does this mean there is too much old phosphor/binder/filler material present and it's shielding the aluminate from the radium?


The radium needs to permeate the phosphor to get a good energy transfer.
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How much radium was generally included in repair kits?


A typical radium dial watch had on the order of a microcurie (microgram) of radium. That should give you some idea.
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Could it be easily extracted? Would it even be practical to attempt an extract of the radium or is it present in very minute quantities?


It is present in minute quantities, but that has no bearing on the feasibility of extracting it. You'll have to use your Geiger counter to track its progress through any processing, but radiochemistry with tracers is no great trick.

I can't give you a ready made procedure to follow off the top of my head. But radium chloride is extremely soluble, and radium sulfate is the most insoluble of all alkaline earth sulfates, and the least soluble of all known radium compounds. A little barium was used as a carrier to assist in precipitation (but may be present in the phosphor mix in some amount).

So, extract the phosphor with a minimal amount of HCl solution (try leaching in a Hirsch funnel until the radiation is gone?).

Simply drying the extract (HCl is volatile) and redissolving in the minimum amount of water and mixing with the phosphor is one possibility, but the highly soluble radium chloride is undesirable.

It can be precipitated by the addition of dilute H2SO4 (or converted to the sulfate in place if adsorbed onto something). Once formed, the sulfate, being insoluble is not affected by a mild alkali (like bicarbonate) that might be used to neutralize residual acidity.

The radium paint makers actually kept their preparation procedures for the brightest glow from the least radium as trade secrets.

MyNameIsUnnecessarilyLong - 7-12-2014 at 02:05

Quote: Originally posted by careysub  

The radium needs to permeate the phosphor to get a good energy transfer.


I suppose I should look for the finest mesh glow powder available?
Quote:
It is present in minute quantities, but that has no bearing on the feasibility of extracting it. You'll have to use your Geiger counter to track its progress through any processing, but radiochemistry with tracers is no great trick.

I can't give you a ready made procedure to follow off the top of my head. But radium chloride is extremely soluble, and radium sulfate is the most insoluble of all alkaline earth sulfates, and the least soluble of all known radium compounds. A little barium was used as a carrier to assist in precipitation (but may be present in the phosphor mix in some amount).

So, extract the phosphor with a minimal amount of HCl solution (try leaching in a Hirsch funnel until the radiation is gone?).

Simply drying the extract (HCl is volatile) and redissolving in the minimum amount of water and mixing with the phosphor is one possibility, but the highly soluble radium chloride is undesirable.

It can be precipitated by the addition of dilute H2SO4 (or converted to the sulfate in place if adsorbed onto something). Once formed, the sulfate, being insoluble is not affected by a mild alkali (like bicarbonate) that might be used to neutralize residual acidity.

The radium paint makers actually kept their preparation procedures for the brightest glow from the least radium as trade secrets.



Lots of good info here, thanks! Why is the chloride salt not as desirable? Would it absorb humidity over time and decrease glow?

Would it be better to mix the chloride salt with the phosphor and dry it, then treat with H2SO4? Or precipitate first then mix? I'd think the former would give a better coat on the phosphor crystals.

Mailinmypocket - 7-12-2014 at 05:58

What a nice find you have there. Very jealous! :P

careysub - 7-12-2014 at 06:18

Quote: Originally posted by MyNameIsUnnecessarilyLong  

Lots of good info here, thanks! Why is the chloride salt not as desirable? Would it absorb humidity over time and decrease glow?

Would it be better to mix the chloride salt with the phosphor and dry it, then treat with H2SO4? Or precipitate first then mix? I'd think the former would give a better coat on the phosphor crystals.


My thinking is that the soluble radium chloride might leach out if exposed to humid environments. It would be better if it was insoluble (which also precludes human absorption).

Regarding the best procedure? I do not know.

You would need to test any planned permeation procedure with your phosphor sans radium first, to confirm that it does not interfere with its phosphorescence.

Look up the "Radiochemistry of Radium" document for more information about radium's chemical properties.

MyNameIsUnnecessarilyLong - 11-12-2014 at 02:34

I added about 10 mL of 31% HCl to the radium and shaked it vigorously for a minute then left it sit overnight. I then diluted it by half with distilled water. When I held the geiger up to the test tube the mixture was in, the solution was mildly radioactive while the solids at the bottom gave the strongest readings. I filtered the mix and after about a dozen washes with distilled water (room temp) and at around 30mL total, the filtrate gave only mild readings while the filter residue gave the most. The cpm of the residue did not seem to change after several rinses.

RaCl2's solubility is 2.5g/ml so that should've been more than enough water to capture it. This probably means the chloride salt wasn't formed by the HCl treatment, right? Should the radium be boiled with the HCl instead of reacting at room temp?

hyfalcon - 11-12-2014 at 05:35

If you boil it, make sure to use some sort of cover. A vigorous boil will atomize some of the solution and make it airborne. Not a good thing for the lab I would bet.

careysub - 11-12-2014 at 14:50

Quote: Originally posted by MyNameIsUnnecessarilyLong  
I added about 10 mL of 31% HCl to the radium and shaked it vigorously for a minute then left it sit overnight. I then diluted it by half with distilled water. When I held the geiger up to the test tube the mixture was in, the solution was mildly radioactive while the solids at the bottom gave the strongest readings. I filtered the mix and after about a dozen washes with distilled water (room temp) and at around 30mL total, the filtrate gave only mild readings while the filter residue gave the most. The cpm of the residue did not seem to change after several rinses.

RaCl2's solubility is 2.5g/ml so that should've been more than enough water to capture it. This probably means the chloride salt wasn't formed by the HCl treatment, right? Should the radium be boiled with the HCl instead of reacting at room temp?


This suggests to me that the radium is probably in the form of the sulfates and will not react with the HCl - no displacement occurs.

I should have thought of this.

Curie also had to deal with the situation of extracting radium sulfate from ore. She did a first digestion with HCl to remove other materials, but to extract the radium sulfate she boiled the ore with sodium carbonate to neutralize all of the sulfate present, then washed with water, and then dissolved with HCl.

So give that a try. It is how Mme Curie did it. (Also do read through the Radiochemistry of Radium doc. I have not reread it in some time.)

Very strong HCl should not be needed for what you are doing.

Bert - 11-12-2014 at 16:42
Quote:

So give that a try. It is how Mme Curie did it.


Mme. Curie was also in the habit of strolling about with vials of her various radioactive extracts including Radium and Polonium salts in the pockets of her lab coat- Her personal effects and papers are all still sufficiently hot that their curators are required to wear protective equipment while handling (and will remain so for centuries to come). All her stuff, right down to her kitchen cook books.

I have got some WWI aircraft instruments from a plane grandfather washed out in France, (clock, altimeter) with Radium painted dials, hands and indicators. I tried to get these looked at by an instrument repair shop. They refused to open the cases, and pointed me to online information on how such things are handled today.

I'm not opening the cases either.

careysub - 11-12-2014 at 19:14

Quote:


Quote:

So give that a try. It is how Mme Curie did it.


Mme. Curie was also in the habit of strolling about with vials of her various radioactive extracts including Radium and Polonium salts in the pockets of her lab coat- Her personal effects and papers are all still sufficiently hot that their curators are required to wear protective equipment while handling (and will remain so for centuries to come). All her stuff, right down to her kitchen cook books.


Similarly, many early chemists succumbed quite early in life to crippling illness and death due to their ignorance, and cavalier atttitudes (when ignorance provides insufficient explanation). Scheele dead at 44; Bunsen succumbing twice to arsenic poisoning, then blinding himself in one eye; crippled Humphry Davy, leaving him dead at 51; and so on and so on.

This is relevant to a discussion of the science that they did? When we discuss any of Scheele's techniques or discoveries do we always hasten to add - "but he poisoned himself you know".

Does that indicate that the many toxic substances they worked with during their careers are just too, too dangerous for anyone here to contemplate handling?

Safe procedures are known today, and keep people out of trouble when following them.

Minute quantities of radioactive materials are no different.

(The absence of these frequent "oh but its so dangerous" on the energetic materials threads astounds me. Not that I think they belong there, discussion of appropriate safety measures are far more useful - it is that people feel that they belong here but not there.)
Quote:
I have got some WWI aircraft instruments from a plane grandfather washed out in France, (clock, altimeter) with Radium painted dials, hands and indicators. I tried to get these looked at by an instrument repair shop. They refused to open the cases, and pointed me to online information on how such things are handled today.

I'm not opening the cases either.


You certainly can't get into any trouble that way. As these things are collectors items I am not sure why you would want to. BTW- aviation instrumentation always had much higher levels of radium than found in consumer clocks and the like, sometimes far higher, since instrument visibility was crucial.

[Edit: The instrument repair shop certainly should not have worked on those instruments. They didn't have the proper equipment (radiation detector, for starters) or training. The NRC licenses entities that employ people to ensure that that proper equipment, training, and procedures are followed. The rules do not forbid servicing these instruments - they state that they must be serviced by someone with the appropriate license, and thus are certified to be competent to do it.

This is in no way different in principle from work place regulations for handling and storing chemicals.

It is not possible to work in radiochemistry at all unless you at least have a Geiger counter, and know how to use it, as the OP above does.]

[Edited on 12-12-2014 by careysub]

[Edited on 12-12-2014 by careysub]

Dan Vizine - 28-6-2017 at 10:49

Recently, I have needed to try and rejuvenate clock numerals painted with radium paint. The prevailing wisdom is that it is possible to re-apply a layer of Cu doped ZnS (or Sr aluminate, as above) to accomplish this. In actuality, I can't find a description of a successful re-activation. I've searched here, and this thread is the best one I found, close, but no cigar. Google searches have not been very productive, either. Has anybody ever seen a description of a success story? If so, is there anything that you can tell me? Thanks.


[Edited on 6/28/2017 by Dan Vizine]