Arsenopyrite effects on assay process?



New Member
During a fire assay that contains a lot of arsenopyrite, what if any of the arsenic will escape as volatized AsIII versus how much of the arsenic will be retained as an oxide in the slag. Of course I'd prefer all of the arsenic be retained in the slag by using the proper proportions of litharge and niter in the flux, but I'm curious how much if any arsenic escapes the fusion process.


Hi Wags:
Interesting problem.

The heat of the fusion is going to break down the arsenopyrite, the iron will mostly report to the slag (some to the lead button). Samples high in sulfur will sometimes form a matte layer on top of the lead- generally considered a bad thing- and the arsenic may collect in this layer as well. But if you are going to cupel the lead button, the arsenic will oxidize at that point anyway.

I don't know of a fluxing agent that will complex with the arsenic to keep it in the slag rather than oxidizing or reporting to the lead button.