The thermal shock on the crucibles has proved to be too much. Recall that the Meker burner did not generate enough heat to reduce the ash mixture to elemental material and salts, but it did come close. The solution then, or so I thought, was to use more Meker burners set up in a tripodal fasion. This (I patted myself on the back a few times for this) would allow greater control over slow heating as well as provide more actual area on on the crucible which was being heated so as to not develop "hot spots" on the crucible itself (slow heating is ineffective if the thermal shock is due to one area of the crucible expanding while another cool area does not.)
I set up (painstakingly) a couple of stands with Meker burners perfectly in place for the tripod along with the crucible at the optimal height and then started up all the Meker burners at the lowest possible gas flow. I increased the gas flow slowly on each of the burners over the course of about twenty mintues, carefully monitoring all of the surroundings to make sure they were not overheating.
Long story short the heat load was too much for the dry powder fire extinguisher which comes standard on all of the hoods in the lab. The heat triggered nozzle fired fine yellowish powder all over myself, the setup I was so proud of and half of the lab. A picture (of course) of the misery will follow shortly after I get it off of Krista's camera.
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