Some of the problems people have,
Not preprocessing the materials: separate types of materials, incinerate when needed, leaching base metals, removing solder, trying whole circuit boards where acid cannot reach copper under mask but gold can plate to this un-dissolved copper, skipping base metal removal before trying to dissolve gold and only plating the gold to base metals un-dissolved, this list can go on.
Using too much acids to get the job done, too much nitric can be a problem.
Working like a blind man, dissolving metals in solution with out using testing methods to determine what metal may or may not be dissolved in solution.
Using too much nitric to begin with, and then not eliminating nitric (or other Oxidizer) before trying to precipitate their metal from solution.
Dirty solutions base metals, organics or other contaminates in solution are very hard for the proper precipitant to happen.
These and many more mistakes (too many more to list depending on process) can easily be overcome with some study before diving off the bridge of refining before studying to see what water or rocks are under that bridge, it will take some time to do that foot work, but the outcome will be more positive.
Sounds to me you have made many of these mistakes, well that is the hard way to learn, like banging your head against a wall to get the house remodeled.
I would test your solution for values using stannous chloride. (De-NOx) before testing this can be done with small portion like a test tube or few drops of solution
Assume values may be in un-dissolve materials, do not discard anything till you know where and what you have.
if you cannot precipitate gold from solution using normal methods a copper buss bar is a good tool to have in your box.
You now have found this forum, with a gold mine of information, spend time in this mine and learn, what is under that bridge before you dive in, it may seem like an awful lot of work to get the gold, but with exploring this mine of information you will find many more nuggets of values, and be well on your way of melting those valuable metals than you will by just banging your head against that wall.