ar with smb after precipitating gold

[arthur kierski]

i have 10liters of ar in which i precipitated gold with smb without using urea or boiling down(3times) as one has to do----i suspect that there is still gold in these 10liters---how can i recover the gold that i think remains in the ar solution?these 10liters are from various ar solutions tha i put together in a vessel.

 

[markqf1]

Arthur,
Kinda sounds like a "stockpot".
Have you tested the solution (or a sample of it) to see if it contains any gold?
You could boil down a small sample in a test tube and test with SNCL2.
I'm really not the one to be giving you advice but, I would think the addition of copper should do it.
And then of course, it would have to be refined again.
You will have to add enough copper to kill all of the acid if you don't want to evaporate it all out.
What is the ph and is there any nitric left in it?

Mark

 

[arthur kierski]

mark,i think there is still acid(nitric ) in the solution and smb---it is a kind of stockpot,but i am in doubt if adding copper the smb will make a mess with the copper----anyway i will take your advise and will concentrate some solution and make the stanous test---if gold present i will see what to do----thanks ---this problem arise because of(my)laziness to do the correct thing in the first time

 

[donnybrook]

Arthur,
Because you have so much solution just start adding aluminium foil to this. You will see the brown or black powder exchanging with the foil and then falling. Keep adding until there is no more reaction or as I was once advised until you see green powder or copper coming to the surface (the Periodic Table and reactivity). I usually keep adding the foil. Let it settle overnight or if the solution is still on the dark side add some Hydrochloric acid ( small amount) which should kick the process of again. You should have a clear or slightly green solution with the precipitate on the bottom. Siphon of with a small plastic fish aquarium type tube; about a quarter of an inch,then filter the precipitate out. Dry this and either smelt or redissolve in AR and begin the process which will now be a reduced amount of material to redissolve. Furnacing is your choice if you are sure you have just PM's. It will save you a great deal of time.

donnybrook

 

[arthur kierski]

thanks donnybroock and welcome to the forum

 

[donnybrook]

Thanks Arthur. Just a small trick with aluminium I have had to use before. I have lost gold because I failed to remove nitric or I lost the chloride due to over boiling etc and thought there was nothing in it. A five gallon plastic bucket is all you need. If you have ten litres add another 5 litres of boiling water (might help with nitric) and begin adding the foil. If you get no reaction which could be slow to kick off add a small amount of hydrochloric acid. You will (or might) get a rotten egg gas smell (hydrogen sulphide gas??) because of the SMB but you will get what you lost back including other metals such as Palladium or Platinum if there as well as Copper which will come up as a green powder and drop during the exchange.

Again thanks for the welcome.
Donnybrook Australia