Interesting way to recover gold from materials

[niels-chemist]

I would like to point your attention to this open-access publication where they dissolute gold without the use of toxic and reactive nitric acid: https://chemistry-europe.onlinelibrary.wiley.com/doi/epdf/10.1002/cssc.202201285
Instead they use triphenylphosphine dichloride and hydrogen peroxide, although oxayl chloride works as well

If you have questions about the content (or other chemistry questions), feel free to ask.

 

[anachronism]

There are as you quite rightly pointed out many ways to dissolve gold, but in most cases you are simply swapping one hazard for another.