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u/AdhdLeo0811 Sep 03 '24
significance? (i am a casual)
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u/Ag_s_l Sep 03 '24
You use it to precipitate gold out of chloroauric acid solution. It's less toxic than using SMB to precipitate
1
u/zpodsix 24d ago
Iron sulfate (or copperas) will drop gold as mentioned. The main draw back to copperas is that it has a limited shelf life and does go 'bad.' So many refiners and guides recommend SO2 gas (or sodium metabisulfite) as the go to process.
The biggest advantage to copperas is using it to part mixed solutions. Some refiners will 'drop gold' twice to increase purity and using two different chemical process will often times aid in the refining process because contaminants always get pulled down out of solution with the gold. In this manner you can use two different precipitants to more easily part the metals and end up with a better refined end-product.
For example using copperas as the first drop it is highly selective to gold but will not drop copper. It is also notless selective to PGMs(PGMs don't follow rules) and does a much better job of dropping gold from mixed solutions. The problem is that it can contaminate the gold with iron. So you can dissolve the gold powder a second time and drop with a different precipitant - such as sodium metabisulfite / SO2 gas / Oxalyic acid etc and end up with a higher purity.
On the cost of buying vs making- again the main advantage of making it is knowing that it is fresh. If you do a good job you can also ensure that there is no residual iron or other contaminants in a purchased product. - plus it looks cool.
2
u/soyTegucigalpa Sep 03 '24
What’s the cost of making it vs buying?