Hello all,
This is my first time doing this. I am doing a gold recovery from CPUs via Aqua Regia/ FeSO4 method for a chem project.
For more project information see here: https://chemicalreport99.blogspot.com/
Primary sources have been
-Recovery and Refining of Precious Metals by CW Ammen (1997)
-Sheng, Peter P., and Thomas H. Etsell. "Recovery of gold from computer circuit board scrap using aqua regia." Waste management & research 25.4 (2007): 380-383.
-Marsden, J. O., & House, C. I. (2006). The Chemistry of Gold Extraction, Second Edition (Vol. 2nd ed). Littleton: Society for Mining, Metallurgy, and Exploration, Inc.
I added 500mg of Ferrous Sulphate Heptahydrate after the evaporation/denitrification step, and observed a brown cloudy precipitate along with nitrogen dioxide gas bubbling. It turned out I actually had a lot more nitric acid than I thought present, so I added excess Ferrous Sulphate until I had a cloudy brown mixture with unreacted ferrous sulphate crystals at the bottom. I centrifuged the mixture and the cloudy brown mixture did not settle at all. This means that the brown color is in solution and I haven't precipitated anything. I have left the samples to hopefully separate over the weekend, but any interim advice would be appreciated. What happened and how can I get the gold out??
This is my first time doing this. I am doing a gold recovery from CPUs via Aqua Regia/ FeSO4 method for a chem project.
For more project information see here: https://chemicalreport99.blogspot.com/
Primary sources have been
-Recovery and Refining of Precious Metals by CW Ammen (1997)
-Sheng, Peter P., and Thomas H. Etsell. "Recovery of gold from computer circuit board scrap using aqua regia." Waste management & research 25.4 (2007): 380-383.
-Marsden, J. O., & House, C. I. (2006). The Chemistry of Gold Extraction, Second Edition (Vol. 2nd ed). Littleton: Society for Mining, Metallurgy, and Exploration, Inc.
I added 500mg of Ferrous Sulphate Heptahydrate after the evaporation/denitrification step, and observed a brown cloudy precipitate along with nitrogen dioxide gas bubbling. It turned out I actually had a lot more nitric acid than I thought present, so I added excess Ferrous Sulphate until I had a cloudy brown mixture with unreacted ferrous sulphate crystals at the bottom. I centrifuged the mixture and the cloudy brown mixture did not settle at all. This means that the brown color is in solution and I haven't precipitated anything. I have left the samples to hopefully separate over the weekend, but any interim advice would be appreciated. What happened and how can I get the gold out??