[Rockhounds] Elutriation

[Kreigh Tomaszewski]

Jim,

Your description was clear enough I'm sure I could build something that 
worked, but I would still like to see the paper as I am sure it would 
save me a lot of time experimenting to make things work right.

Kreigh



On Tuesday, Jan 6, 2009, at 22:35 America/Detroit, Jim Murowchick wrote:

> 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
>>>
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>>
>
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