Hi Will - i sort of do the same thing, first i pyrolyze(high heat > 500C, NO air), grind, sieve through 3mm mesh. What you end up with is: 1. fines <3mm which contains carbon(lots of it), some wire/pins, small beads, ceramic and fillers etc. 2. bigger bits >3mm which contains metal beads, pins, cermanics, small metal heatsinks of various composition, and bits that need regrinding.
The metal beads are generally soft and contain solder, silver, Pd, Au. The solder tends to flow during pyrolysis and collect more solder and PM's along the way forming beads greater than 3mm. The beads i collect, and when their is enough i melt and skim off the crusty litharge that forms at temperatures just above the melting point of the allow beads. The more and more you skimm off the higher the temperature requirered to keep it in the molten form. At the point litharge itself becomes molten is the time i pour into a mould ready for cupellation.
The remainder, after removal of beads and large pins/heat sinks, is treated with a magnet to remove any iron, then it is mixed with the litharge from above and the <3mm fines to form a mix ready for ashing through my pipe asher.
This produces a hole bunch more metal beads which are treated as above, the remainder is inspected to ensure complete ashing has occured, if so, then it is smelted using flux and them poured into a mould ready for the cupel.
Bit of a novel, but thats how im trying to do it, what do you think?
Deano
