Gold drop issue

1.5kg of rolled gold steps as followed
incinerated
Nitric bath total of 5l
Filtered
All foils and filters re-incinerated
Dissolved in AR with incremental nitric doses
Filtered till clear solution
SMB drop.
Now this is where my problem starts instead of a nice thick layer of precipitation i ended up with what looks like super ultra fine gold that turned liquid purplely/blueish colour that looks black/green from a distance
The gold seem to be to fine to settle or filter been a weeks and still nothing has settled. So where do I go from Here??

1 so can I evap and boil of excess smb and re add hcl and nitric to redissolve gold?

2 if not then what is the best plan to recover the gold ???

Thanks Ben

There is two possibilities as I see it.
Too much Nitric, which sounds a bit off,
the way you describe your procedure.
The other thing is that the SMB is not SMB.
The color you describe is similar to a Stannous test
so it could be collodial gold.
What did your stannous say by the way?
And what amount of liquid do you have?

Stannous was positive for gold before the drop I had around 1000ml after bit of evap then used 40g of smb (which until now never been an issue) after the drop I tested again still positive so like an idiot I kept a adding smb till test was negative.

The only thing that was different to any other I’ve done was the solution was left overnight before the drop and temp was around 2-3 degrees when adding the smb

Try add a bit of HCl, slowly. It never hurts and sometimes when you run out of HCl the SMB stops working properly.

SMB + HCl -> SO₂ which drops the gold.

Göran

Göran
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That was my initial thought.
So after multiple attempts of filtering hoping that filter would eventually clog and catch the precipitate.

I ended up with around 2l of solution which split in 2 so 1l I started to evap to drive off any excess smb I then started to add hcl and (again like an idiot) I started to add some nitric did get a reaction and some fuming and solution has gone real dark green/yellow unlike the remaining untouched solution that is still blue ish

However stannous giving me a orangey/reddish colour

So in short I am out of ideas apart from sticking in a load of copper and leaving it for month

You surely know to denox instead, with urea/sulphamic acid

There was no need to Denox as there was no excess nitric