Re: Uranium colors

[Doug Turner <turners@earthlink.net>]

Mike, Yes the colors are indicative of the chemical form.  The Dark brown
color is UO-2 and the black color UO-3 both highly insoluble ( ceramic fuel
pelleta are UO-2).  The "Yellow Cake" is probably uranyl nitate or ammonium
diuranate both of which are highly soluble and have a biological half life
of hours to days in the human body.  Uranium hexaflouride is a whitish
yellow which is also very soluble with a short biological half life , but
the fluoride toxicity is controlling,

Doug Turner <turners@earthlink.net>

   At 09:32 AM 8/21/96 -0500, you wrote:
>I am editing a uranium safety course for use throughout the DOE complex,
>and I have a question about colors.  The course that I inherited contained
>the following statement about yellowcake.
>
>"The final color [of yellowcake] can actually range from yellow to orange
>to black depending on the chemicals used and the drying temperature. The
>final color is important when determining biological effects if uranium in
>this form is taken into the body, as the darker color indicates that the
>material will have a lower solubility, meaning the uranium will stay in our
>body longer.  A lighter color indicates that the material has a higher
>solubility meaning the uranium is more quickly removed by normal body
>functions."
>
>Is it really possible to make such a broad generalization about color and
>solubility?  Is this paragraph helpful?  Does anyone know where this
>information comes from?
>
>There are many other threads that could be pulled from this quote, eg
>obviously low solubility implies low absorption rate as well as low
>clearance rate, so it depends if the intake is inhalation or ingestion.
>Also, the color of materials containing uranium is extremely complicated,
>depending on many things, including impurities, the particle size, and the
>oxidation state or states.
>
>Thanks to several RadSafers who made comments on the draft DOE uranium
>safety course.  If  anyone else would like to see a copy of the draft
>course, please reply to me directly.
>
>"Shlala gashle" (Zulu greeting, meaning "Stay safe")
>mike (mcnaught@LANL.GOV)
>
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