Hello all and it's been a while;
To awaken this thread from last March, my routine has evolved to thus:
1. After obtaining material ready for AR through either removal of gold from china and glass, or from gold filled, heavy gold plate (think military contacts) through Nitric and rinse, I then AR the batches.
2. I confess (on my knees weeping) that I still pre-mix the AR.
3. It cooks, under heat, for approx. four hours. In the latter stages I dilute and let steam.
4. I do use the Butyl Diglyme to drop the gold per LazerSteve procedure.
4a. After dropping, I save the used AR and when I've collected a quart or two, I use SMB to drop. I always get some precipitate, uncaptured Au plus PGM? I'm saving the filters until I know what to do with them.
5. Rinse with hot HCL (mixed with some hot water), rinse with water, dry, melt and produce the buttons.
6. I reclaim any silver in the waste using copper. I then raise Ph to 2.5 and drop copper using cast iron. I then raise Ph to 5-6 and the iron drops.
7. left now with a Ph neutral liquid slightly green, I gently heat and add ammonia and a yellow-green misty substance precipitates. I filter this out (What is it?) Is it Nickel? PGMs? In any event, my waste liquid is clear with the Ph of water and I dispose.
These buttons now, having done this for over a year are so much cleaner than when I first started. I have multiple two inch jars separated into two classes - from glass and from metals. With metals, I measure what I start with (contacts I just weigh after torched into flakes - the gold fill is noted), and record the results. I maintain a close yield to what I start with on the gold fill. 100g of 1/20 12K should yield 2.5g gold. I routinely get 80-90% of that amount, sometimes worse (waste, wear and tear of the fill, hopefully not wasting anything through the chemical process or dropping process).
My next step is to either assay the gold and/or send some to a refiner to establish my selling process. I will explore two places locally here in Minneapolis, but I've heard good things about a refiner in Texas.
So what's my point?
1. I will commit to start adding the nitric slowly instead of pre-mixing the AR. Since you all are practicing this, I should be current.
2. I will find what it takes to test for PGM. I'm sure all those re-SMB dropped filters from previous AR batches contain PGM as the DMG selects for AU only.
3. What is this yellow-green misty precipitate I described above? ("left now with a Ph neutral liquid slightly green, I gently heat and add ammonia and a yellow-green misty substance precipitates. I filter this out (What is it?), my liquid is clear, and I dispose."
