[Rockhounds] Geology in Progress

[Earl R. Verbeek]

Hi Nate,

I'm just now getting caught up on a week's worth of e-mail messages and ran
across yours on flotation methods.  I don't have anything to add right now
on the commercial aspects of this process, but if you'd like to demonstrate
it in your own home it's easy to do.  Just get some seltzer water, some
peanuts, and some raisins.  If you put peanuts and raisins in plain water
you'll see they both sink -- both are denser than water.  But if you place
them in seltzer water you'll find that air bubbles adhere to one and not
the other, so you'll get a neat separation.  I forget whether it's the
peanuts or the raisins that float, but it's a simple and effective
classroom demo to use to illustrate the process.

The beauty of such flotation methods is that you don't have to use heavy
liquids for mineral separations -- those liquids (bromoform, Clerici
solution, etc.) aren't the most user-friendly chemicals in the lab. 
Instead you can use a liquid that is less dense than any of the minerals
you hope to separate, but with the proper additives one will float and the
others sink.

            Cheers-   Earl Verbeek

On Sun, 4 Jan 2009 21:42:06 -0500,  wrote:
> Pete, et al
> I did a quick search on "magnetite flotation" and came up with a number
of
> hits that were suggestive however most of the references did not permit
> articles to be downloaded so only brief snippets could be viewed.  Froth
> flotation methods were mentioned several times and it makes me wonder if
> the
> natural froth generated by heavy wave action might preferentially bind to
> magnetite and enable it to float.  Various polymeric or other chemical
> additives also seem to be important in flotation mineral processing
> applications.  It makes me wonder what the effect might be of various
> impurities in the water near the RI beach that Larry visited.
> 
> Isn't it amazing where a simple observation can lead?  I'll bet someone
on
> the list has some experience in flotation methods and can give us some
> insight.
> 
> best regards,
> Nate Martin
> Lexington, MA
>