Graphite Crucibles and Rare Earths

H

herbamatic

New Member
#1
Hi All, about to delve into REE analysis and have some lingering thoughts about what crucibles to use.

1) if graphite crucibles (G-C) can be used for fusing rocks using Na2CO3 or Na2O2 (Na-peroxide) at a temp range of 1000-1100C?
2) If so, how many times can each crucible be used before it goes bad? or results inherit contamination from prior fusing?
3) Could there be contamination from graphite crucible for trace elements (particularly REE)?
4) Would you recommend a different kind of fusing agent instead of Na2CO3 or Na2O2?
5)If graphite crucible is not appropriate what else can I use instead (Zirconia crucible instead for fusing rock)?

thanks in advance.
 
fireguy

fireguy

Supermoderator
#2
herbamatic said:
Hi All, about to delve into REE analysis and have some lingering thoughts about what crucibles to use.

1) if graphite crucibles (G-C) can be used for fusing rocks using Na2CO3 or Na2O2 (Na-peroxide) at a temp range of 1000-1100C?
2) If so, how many times can each crucible be used before it goes bad? or results inherit contamination from prior fusing?
3) Could there be contamination from graphite crucible for trace elements (particularly REE)?
4) Would you recommend a different kind of fusing agent instead of Na2CO3 or Na2O2?
5)If graphite crucible is not appropriate what else can I use instead (Zirconia crucible instead for fusing rock)?

thanks in advance.
Sodium peroxide fusions, and similar fusions, would typically be done either in pure graphite crucibles, or in platinum crucibles. The platinum crucibles can be reused many times, but are obviously very expensive. The pure graphite crucibles can be used "several" times, the exact number dependent on flux used, temperature, etc.

I am not aware of any contamination from the graphite, but you should verify any initial positive results with an independent laboratory.

You may also want to investigate lithium metaborate fluxes, sodium hydroxide, sodium peroxide, etc. I would stick with whatever is most common for the type of test you are doing.
 
Top