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?