Refining platinum

[100tific]

Hello!
I was recovering platinum from an alloy with different metals (Au, Pt, Pd, Ag, Cu, Zn....)
I dissolved the alloy in AR and i filtered to separate the silver chlorides that had formed.
Later, I added sulfamic acid with the hot solution with the intention of eliminating the nitric acid until the bubbles stopped coming out.
I was about to add ammonium chloride to form ammonium hexachloroplatinate, when suddenly, I noticed that a canary yellow powder was beginning to form at the bottom of the flask. I HAD NOT ADDED THE AMMONIUM CHLORIDE YET.
What is happening? What compound is this?
Why is it formed when hot sulfamic acid is added?
someone knows?

 

[Swissgoldrefiner]

As sulfamic acid by product in nitric acid is sulfuric acid, it may be an insoluble salt of sulfate. Probably lead sulfate, but the color dont match...

 

[Yggdrasil]

As sulfamic acid by product in nitric acid is sulfuric acid, it may be an insoluble salt of sulfate. Probably lead sulfate, but the color dont match...

Way too much, so I really do not know what it might be.
Are the elements listed the only ones there?

 

[anachronism]

Hi how much of this alloy did you start with and do you have a picture please?

 

[100tific]

Hi how much of this alloy did you start with and do you have a picture please?

I started with 131.69g of sample.

Spectrometry
Cu	79.23
Au	628,3
Pt	102,72
Zn	54.02
Ag	135,35

As Ag was upper than 10% y added 50g Cu , and i did it shot blasting, small pieces. then i dissolve it in ARand i filter it to remove the AgCl. Some pieces continue without dissolve, so i put them wit a little bit more AR and then i mix both pregnant solutions. I whased the filter with HCl and i added 30g Sulphamic acid slowly and in hot, this one reacted doing bubbles and with a bit of time I have that i showed in the firsrt pictures.

 

[Xing]

in my research paper, have done the similar work. you can dissolve in the HCl and oxiding solution, then Au could be extracted by DBC, then reduce to Au powders.