Got it.
Another member advised that he used litmus paper to check the ph.
Yes, sometimes it is good to check the pH, but your current operation do not need that.
After being de-noxed with sulphalmic (yes, I know to heat and dissolve and diluted with water I didn’t expect the reading to be off scale acidic. I was shooting for ph in the 2-4 range.
You heat the whole solution to almost boiling, no need to dissolve the Sulfamic, and diluting now is counter effective, you want the solution fairly concentrated.
After the solution is free of Nitric and Cold, add some ice cubes and dilute it before filtering it crystal clear.
I may still have used too much nitric, but it’s a fraction of what I initially used. And, I continue to cut back. I’ve basically watched Sreetips videos several times.
He uses tiny quantities of nitric.
Yes and so should you
As far as source material, on electrical/computer parts, I have begun trimming and removing undesirable material with surgical precision. I’ve also added some small gold pickers that I acquired from years of panning and gem hunting.
DO NOT MIX material, keep magnetic and non magnetic apart. No PCB parts is supposed to be contacted by AR.
Trim close to "fingers" plated PCB bodies are very thin so no need to bother with it.
You can put them in a Cupric Chloride etch and keep it bubbling for months if you wish, they need no maintenance.
When they are clean flush them thoroughly and process the sludge.
I made a major mistake reusing the contaminated HCL this time. Won’t happen again.
I’m currently using ferrous sulfate instead of SMB.
I understand that zinc and citric acid will also precipitate gold.
Zinc will not precipitate Gold it will cement all less reactive metals in solution including Iron, Copper and what not.
Citric acid I have not heard that can be used for precipitation, but Oxalic acid, Acetylic acid among others can.
I’ve also decided not to spend time trying to recover tiny amounts of gold from my waste.
Just neutralizing, evaporating and will incinerate solids.
Follow the dealing with waste thread and you will be good.
ty