definite solution

[arthur kierski]

when i drop gold with smb or sodium bisulfite ,together with the gold comes down a grey or white precipitate which is very irritating-------question:how to separate the gold from this greysh precipitate-?-----question 2:how to avoid this precipitations before droping with smb?
i know this topic was already treated in the forum but i would like a practical solution
thanks all for replies
up to now i dissolve this gold +grey precipitate in ar again(for a second time)
Arthur

 

[4metals]

If you add too much precipitant the grey is copper. Fortunately it is soluble in HCl so a warm acid rinse cleans it up but it's best not to over precipitate.

 

[arthur kierski]

thanks 4metals for your reply----i did that and it worked fine----usually i over estimate the quantity of gold present in solution and add to much precipitant

 

[gorfman6154]

usually i over estimate the quantity of gold present in solution and add to much precipitant

Good afternoon Arthur, i used to do the same as you. I would over estimate the expected yield, and end up putting in too much SMB. One easy way to overcome this, is to only add about half of the SMB at the start, then test with Stannous Chloride. If it tests positive for Gold, add a little more SMB, how much more to add is determined by how dark the test is. The darker the test, the larger amount of SMB, if the result is faint, just a little more. Keep adding small additions until your spot tests show negative for Gold.

The total amount of SMB that you will add will come with experience.

Plus it's a great way to save on chemicals, and keep your costs down 8) . If any other Forum members have any other ideas, let us know.

Good Luck Arthur, Gorfman

 

[arthur kierski]

thanks Gorfman,your idea is very interesting---i will follow your idea-----save smb and no nasty grey powder------thanks again

 

[gorfman6154]

thanks Gorfman,your idea is very interesting---i will follow your idea-----save smb and no nasty grey powder------thanks again

Arthur, check out Lazersteve's video on using SMB. It's a short video, but worth watching.

Gorfman