Help with my solution

[ovidiuanghel]

Hello everyone,

Even if i am on this forum for a couple of months, i have learned a lot from you and i thank you.For a couple of weeks i've started a project, now i'm facing a problem and i don't know how to handle it.

I proccesed in AP aprox. 700g boards, then the foil in HCL/CL. After that i tried to drop my gold with K2S2O5. I haven't found SMB in my country.

After 48 hours i have a little dust on my jar, the colour of the liquid is not quite clear and the test show positive for gold.

Have i ruined my experiment? Have i added too much potassium metabisulfite? Please help!

 

[lazersteve]

Solution looks nearly if not entirely barren to me.

Your swab looks like a brown false positive, if so you'll smell rotten eggs right after the test as well.

I suggest heating the solution until the smell of SO2 is gone, then tesing again using a crystal of ferrous sulfate.

The mode select switches in the photo are pretty common and typically have pretty low yields per pound so don't expect much gold from 700g (maybe less than 1 gram in fact). Did you get floating foils in the AP reaction or small flakes of gold?

Steve

 

[ovidiuanghel]

Thank you for your replay, i had small flakes i disolved them and the result after droppping gold is a small amount of powder.

How much K2S2O5 it's needed to drop 1g of gold? I think i put too much, about 2 large spoons.

 

[Geo]

equal amounts should work, but when in doubt, double the weight of gold. 1 gram of gold = 1-2 grams of precipitant.

 

[ovidiuanghel]

Steve, Geo thank you for your help