zinc antimony n tin are the big concern.
lead i think has a lower melting point than zinc so if you can regulate you melting temp the zinc may be able to be scooprd out...if there is zinc present.
This stuff seems to melt at a lower temp than my 99% pure lead. This is based only on the time it takes to get to melting in my pot. It also seems very clean. Only a bit of a film on top, no big slag pieces. And thank you for the offer but I’m not that invested in this stuff.i have a lee hardness tester....if you want you can send me a small piece i will test for you
Thanks, Jon