[Rockhounds] Elutriation

[Kreigh Tomaszewski]

Jim.

That is pretty cool. I use a single stage to recycle tumbling grit and 
have to make multiple passes with decreasing water flow. I would like 
to see the paper. Being able to separate multiple grit sizes in a 
single pass would save me a lot of time.

Kreigh


On Tuesday, Jan 6, 2009, at 12:40 America/Detroit, Jim Murowchick wrote:

> For anyone interested, there was a USGS paper, probably from the 
> 1960's,
> that described an elutriation system for mineral separation.  It 
> consisted
> of a series of tall (10-15"?) U-shaped glass tubes (oriented 
> vertically),
> each with a stopcock at the bottom of the U.  Each glass tube had a 
> smaller
> inside diameter than the one upstream, and they were connected in 
> series
> with a rubber tube.  At the start, a separatory funnel with a stopcock 
> at
> the bottom held water, and was at the highest elevation.  At the 
> outflow
> end, a rubber tube from the last U drained into a collection flask.
>
>     With a slow stream of water flowing through the system (feeding 
> into the
> separatory funnel, a slurry containing the sample was drizzled into the
> separatory funnel.  The heavies collected at the bottom of the first U,
> lighter minerals moved on to the second or third U, and the lightest 
> ended
> up in the collection flask at the end.  Fine-tuning of the water flow 
> and
> gradient controlled the separation efficiency, and the separates were 
> then
> emptied through the stopcock at the bottom of each U tube.
>
> I'll try to find the paper, in case anyone wants the specifics, but if
> anyone can provide the reference info, I'd appreciate it.
>
> Jim Murowchick
>
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