Hi Guys,
I've been refining gold for a while now using the AR method and my goal is to get 999.9 using the AR method. But I consistently get 999.6 - 999.8 result instead. I know that because I have been sending to external lab (E.g. Metalor & Perth Mint) for analysis and their ICP OES result shows 999.7 consistently with Ag being the major impurities.
For my process:
1) AR dissolution
2) Spray water to the AR solution to reduce the temperature of the AR
3) Filter the AgCl twice using 10 micron and 5 micron filter
4) Adding urea and precipitate using SMB
5) Wash the precipitated gold using Nitric Acid, water, Sodium Thiosulfate, water, Nitric Acid then water again. I use a mechanical agitator to improve the washing process.
I tried refining the gold twice in the AR solution but the result is the same, 999.7 gold.
Please help me on how to improve my process to get 999.9 gold or perhaps there's some steps that I'm missing.
I've been refining gold for a while now using the AR method and my goal is to get 999.9 using the AR method. But I consistently get 999.6 - 999.8 result instead. I know that because I have been sending to external lab (E.g. Metalor & Perth Mint) for analysis and their ICP OES result shows 999.7 consistently with Ag being the major impurities.
For my process:
1) AR dissolution
2) Spray water to the AR solution to reduce the temperature of the AR
3) Filter the AgCl twice using 10 micron and 5 micron filter
4) Adding urea and precipitate using SMB
5) Wash the precipitated gold using Nitric Acid, water, Sodium Thiosulfate, water, Nitric Acid then water again. I use a mechanical agitator to improve the washing process.
I tried refining the gold twice in the AR solution but the result is the same, 999.7 gold.
Please help me on how to improve my process to get 999.9 gold or perhaps there's some steps that I'm missing.