Have I struck gold?

[Tzoax]

The filters are safely tucked away in a box with some other filters containing the precipitated AgCl and any gold remains. I will build up that stockpile a bit before I burn and process them, I don't see the point in doing a recovery from just one or two filter papers.

I suggest that when processing copper/brass based pins with A/P method, always incinerate all that was left in filter paper along with gold foils , simmer boil with HCl, filter, BEFORE processing with AR. Of course, it works on many ways, but this way several things are accomplished:
- your result will be more accurate
- you will get rid of almost all of the tin. When processing pins (that contains tin) with A/P method not all of the tin goes in solution (stannic chloride), some of the tin will form tin oxides (like in this picture) that will trap the gold. When you incinerate the tin oxide, it will go to metal form, and then you can get rid of tin by simmer boiling it in HCl - the tin will go into solution as stannic chloride and it will free the gold so the AR could react with it.
- by incinerating you will get rid of all organic impurities before AR
- you will avoid possible formation of colloidal gold
- your AR solution will be smaller volume
- the gold will drop faster

If i am wrong, please someone correct me.

 

[bemate]

I suggest that when processing copper/brass based pins with A/P method, always incinerate all that was left in filter paper along with gold foils , simmer boil with HCl, filter, BEFORE processing with AR. Of course, it works on many ways, but this way several things are accomplished:
- your result will be more accurate
- you will get rid of almost all of the tin. When processing pins (that contains tin) with A/P method not all of the tin goes in solution (stannic chloride), some of the tin will form tin oxides (like in this picture) that will trap the gold. When you incinerate the tin oxide, it will go to metal form, and then you can get rid of tin by simmer boiling it in HCl - the tin will go into solution as stannic chloride and it will free the gold so the AR could react with it.
- by incinerating you will get rid of all organic impurities before AR
- you will avoid possible formation of colloidal gold
- your AR solution will be smaller volume
- the gold will drop faster

If i am wrong, please someone correct me.

Thanks for the advice, I'll keep it in mind when I do the bigger lot later on. It will be easier to take care of the incineration when the temperature outside is better as well. I'm thinking of just building my stockpile through the winter and then have an incineration-day come spring, to do all my various filters, chips and contacts in one go, then go back to the chemistry and recover/refine my gold.

As an aside, here is the difference in color from my pure gold and the latest drop from the pins as described above:


As you can see, the one on the left appears almost black because of the flash, but it's a dark chocolate brown in reality.

Edited to fix typo