Nickvc,i think that i misled you and others in my thread---what i wanted to say is:i made a rh sulphate solution,and found out that this solution was contaminated with copper and other ions(like lead,iron nickel)---------- from this finding i have 2options-----the first is to find a chemical ,---to precipitate these ions out of the rh sulphate solution ---------the second solution(unfortunatelly) was to cement out (precipitate) all these metals impurities,including rhodium ,and begin the production of rhsulphate solution from the beginning---clean the rhodium from the impurities and then ,fuse in a furnace with nahso4 ,etc,etc-----i have an idea of how to eliminate the metalics impurities from the rh sulphate solution----but was asking some member of the forum to pass their ideas ,or ways to eliminate the impurities-----thanks for your reply to me---this gave me the oportunity to correct my previous thread----------------------------------------------------------------------------------------------------------------------------------------------------------Arthur Kierski