I'm not trying to be a jerk....but I don't think you've done your homework.
I wasn't kidding when I said 20 people worldwide. It's a very small group of people that handle the isolation and refinement of the lesser known PGM's.
A google search of "iridium refinement" gives this.
https://www.technology.matthey.com/article/52/3/186-197/
From there, you can start pulling the sources they give you.
You honestly will not get any free rides with iridium processing.
You can figure out Pt refinement quite well on this forum. Pd, somewhat. Everything else, snippets. Starting with Gilchrist is never a bad idea.
