Hello Everyone, I received a question from a person new to fire assay. He was asking about fluxes and procedures for the fire assay of materials that are range in the 40-60% copper and 10-40% Iron collectively. This is the set up he has now: Sample size: 5-10g, pulverized and screened, 125um mesh Flux: Lead Oxide (Precious Metal Free) 61% Soda Ash 19.5%, Borax (anhydrous) 9.8% Silica 9.8% Each fusion is run with 60g of flux and 5g of flour to 2000F for 2 hrs. Then cupel and dissolve the bead for ICP analysis. Any suggestions for flux variations to handle these types of samples?

Just wondering how many out there make their own fluxes from scratch and how many purchase flux that is pre-blended to their own specs?