Franklin & Marshall College Franklin & Marshall College

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Trace Element Technique

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A. Copolywax - whole rock powder preparation

1. Thoroughly clean and dry several glass sample bottles (24 ml glass bottles from Thomas Scientific) and lids if clean bottles are not already available.

2. Weigh out 1.4000 grams +/- 0.0002 of copolywax onto a piece of weighing paper (previously weighed and tared). Transfer the powder without loss to the clean sample bottle.

3. Weigh out 7.0000 grams +/- 0.0004 of whole rock powder onto a piece of weighing paper (previously weighed and tared) and transfer to the same bottle as in 2.

4. Carefully rotate sample bottle in your hands so as to mix the powders without letting them touch the lid.

5. Label sample number on glass bottle using the letter T to signify trace element preparation. Do not label the plastic lid. The T is used to make sure you don't confuse major and trace element preparations.

6. Mix sample for 10 minutes in the mixer-mill.

7. If you stop at this step without going onto Part B, store bottle in a dessicator.

B. Press sample to make briquette per demonstration given by your instructor. Normally the sample remains at 40,000 psi pressure for a minimum of 3 minutes.

Do not forget the following items:
1. When pressing samples it is prudent to wear safety glasses.

2. With a magic marker, label sample number on the edge of the pellet. Either side of the briquette can be analysed

3. Place 1/2 of a small kimwipe in the bottom of a pillbox and put briquette into the container and cover with lid. Label the lid of the pillbox.

4. Store pillbox in a dessicator.

5. Clean the glass bottles and caps you used in distilled water, using scrub brush. Rinse in distilled water and then rinse in acetone and let dry in air on a paper towel for an hour or so. Lay the bottles on their sides to dry. Recap and put back into the storage tray.

 

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