Either with lye as stannate, large amounts of hot water or with concentrated HCl or HNO3.
No HNO3 doesn't dissolve it. And there's alot of HNO3 trapped in Stannic acid that's impossible to wash out. Adding HCl dissolves the gold with
Stannic acid.zinc finger - 2-6-2021 at 09:31
I see. So your goal is to leave gold behind and get rid of everything else?
Why don't you use NaOH or KOH and some heat?