solo_voyager

Well, It looks like this project is grinding to a halt for now. After checking around town the only place I can obtain nitric acid is from a chemical supply, 500ml at almost $60. Not worth it to me. I know I said 2/3 oz. in the original post. Don't ask me where I got that number from. I meant 1/3 oz. Not enough to justify that much of another acid sitting around. Thank you both Dave and Chris for your advice on this. If I can find a source for a smaller quantity, I'll give it a try.

OK then, what would be the easiest and cheapest way to obtain a small amount of nitric acid?

Just a little update on my project. After my last post I played with the gold fines a bit more. I tried grinding lightly with the pestel while the gold fines were covered with soapy water in the mortar. The "black" portion became suspended in the water and could be poured off. The soap kept the gold fines from floating on the surface. I was able to remove virtually all the black portion. My assumption is that the "black" was probably lead sulphate and/or iron oxide which was groung finely enough to become suspended and be pourd off with the water. The gold has cleaned up quite nicely with only a couple of possible problems now. It appears that there are some particles of the ceramic material from the mortar and pestel now mixed into the fines. Not a problem. Those will pan out easily. The other problem is that the gold fines are lighter in color than the small nuggets that were removed prior to retorting. My assumption is that this is caused by either residual mercury or possibly metalic lead bonded to the gold. Heating to red heat in an open area should remove any residual mercury and possibly oxidize any metalic lead. Then, treating it with dilute sulphuric acid should turn any resiudual metalic lead to lead sulphate. Finally, I should be able to go back to the "pour it off in water" process again. Does that sound reasonable. Or am I off in la-la land again?

OK, that is what my first impression was way back when. Since posting my original inquiry, I've broken up the button up with a pair of pliers. I placed the pieces into a mortar and worked the pieces back down to a coarse to fine powder again by gringing and pounding with the pestle. The results looks "dirty". Probably the lead and maybe some reduced iron oxide from the retort it was stored in for years. I think I'll grab my pan out of storage tomorrow and try panning it down again to see if I can remove some of the "black" portions. I may not get much of it out because the "black" portions are very very fine. Now, I'm still looking for an answer to question #2: How to remove the lead? I also have a bottle of concentrated sulphuric acid stored away with my mineralogy gear. Will that effectively remove the lead from the gold or is there a better way to accomplish that?

Several years ago I separated all the tweasable nuggets from my poke. The balance, mostly a coarse to fine dust mixed with lead minerals was treated with quick silver and then retorted to remove the mercury. I've had an approximately 2/3 oz button laying around ever since. I don't remember exactly what happened, but my impression was that the lead was taken up along with the gold. As I look at it now it seems to be pretty clean. So, my questions: 1. Has the amalgamation process separates the gold from the lead ore, or was the lead ore included in the button with the gold? 2. If the lead has been taken up by the amalgamation process and is also in the button along with the gold, how can I remove it so that only the gold is left? Thx s-v