Sciencemadness Discussion Board

K-40 isolation

Madlab - 18-11-2011 at 07:43

Does anyone knows how can I extract and isolate K-40 from bananas?

ScienceSquirrel - 18-11-2011 at 07:56

Do you just want the one isotope?

Wizzard - 18-11-2011 at 08:06

It would be far easier to extract it from KOH or KI, which are both far more availble.

Good luck with that though- If it's even possible (which I really doubt it is for anybody who doesn't have a couple hundred million people's worth of taxes), separating K40 from K39 and K41 (both of which are stable) is going to be damn hard, and not any one method commonly used for separating isotopes could be used.

[Edited on 11-18-2011 by Wizzard]

Endimion17 - 18-11-2011 at 10:39

Obviously, he thinks <sup>40</sup>K is is bananas only, due to the "banana dose" fun fact.

I'd suggest more learning before doing any attempts at isotope separation, whether they are viable as in uranium or futile as in potassium.

condennnsa - 18-11-2011 at 10:50

this thread made me interested in reading about this isotope, I didn't know that potassium has naturally occurring radioactive isotopes! and 0.01 % is a lot. i have about 100 kg kno3 fertilizer, so that's 4 grams worth of K-40 in there! is it dangerous to be around?

ScienceSquirrel - 18-11-2011 at 10:50

There are methods for separating the potassium isotopes.
I suspect that you could use a calutron for example.
http://en.wikipedia.org/wiki/Calutron
However you are looking at the thick end of big bucks aka a shitload of money so out of the reach of most.

ScienceSquirrel - 18-11-2011 at 10:54

Quote: Originally posted by condennnsa  
this thread made me interested in reading about this isotope, I didn't know that potassium has naturally occurring radioactive isotopes! and 0.01 % is a lot. i have about 100 kg kno3 fertilizer, so that's 4 grams worth of K-40 in there! is it dangerous to be around?


Sadly only about 1.5g = 4*39/101, you have to allow for the nitrogen and oxygen as well.
It is a radioactive isotope with a long lifetime so it is pretty safe.

Endimion17 - 18-11-2011 at 15:00

Considering these things are few clicks away (Wikipedia), I'd say some people here are quite lazy.

It's highly dilluted in natural samples of potassium and decays to <sup>40</sup>Ar or <sup>40</sup>Ca, both of which are stable. Its rare decays are followed by emissions of weaker gamma rays, electrons and positrons.
We have a shitload of potassium in our bodies and, together with <sup>14</sup>C, potassium-40 is the largest source of radiation we carry around naturally. It's one of the power sources for evolution in living organisms, contributing to mutations all the time.

Panache - 19-11-2011 at 07:53

Are we sure the poster is speaking of the isotope and not the vitamin?