[Rockhounds] Elutriation

[Jim Murowchick]

Hi Kreigh.

    I'm still looking for the paper--it's one of those that I keep finding
when I don't need it, but when I want it, I can't remember where I stashed
it.  I can probably draw a sketch of the system, though, if I can't find the
paper. I'll look for it for a few more days, then I'll make a sketch.

I was going to make the system a few years ago, but found I didn't need it.
Now, I have a student looking at soils in the Bahamas, and we might start
separating out the very fine materials to determine the source of the
airborne dust components. I think the elutriation system might be modified
to make that separation.

Jim


On 1/6/09 9:29 PM, "Kreigh Tomaszewski" <Kreigh at Tomaszewski.net> wrote:

> 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
>> 
>> -- 
>> _______________________________________________
>> Rockhounds at drizzle Mailing List
>> Subscription Services:
>> http://lists.drizzle.com/mailman/listinfo/rockhounds
>> List Home Page, with a link to the List Usage Policy:
>> http://www.eclecticlapidary.com/Rockhounds/index.html
>> 
>