black powder with gold foils

[rasool]

Hi
this is my first try to recover gold from cellphone boards. after depleted about 1.5 kg cellphone boards I placed boards in hot HCl for 4 hours and pins for 2 weeks then I rinsed it .
next step, I placed it in hot HNO3 about 4 hours. white foam formed on the surface and black powder on the bottom of the solution which made it difficult to filter the solution.(pic 1,2,3)
in step 3 I've placed black powder, gold foil and metals in H2SO4 for 4 days. in this step black foam formed on the surface(pic 4,5). in next step I want to placed whole materials in the AR solution to separate gold. Is it possible the gold to cement on black powder before the AR solution is separated?
what is the black powder? what can I do to separate gold foils from black powder? Would it be better to melt all the cellphone boards first and then place them in acids?
I'm sorry that my English is not good and there is probably something wrong with the text.

 

[Martijn]

Hi rasool, welcome to the forum.
You've made quite a mess. I think the base metals have all dissolved and some gold could have dissolved because of remains of HCL in the HNO3 and fallen back out on base metals, but that much black powder will not be all gold from that much cell phone boards.. the value is in the chips. Not sure what you have made there.
I guess some good rinses to get the acid and metal salts out, incineration(without the circuit boards) and an AR leach could work. Don't expect much gold from those boards.

I suggest putting this mess aside and studying the forum and Hoke's book before proceeding.
https://goldrefiningforum.com/phpBB3/viewtopic.php?f=49&t=28521.
Martijn.