Gold is floating after precipitation, plating glass and not dropping!?

[McGettums]

After two successful drops from fingers and boards, I moved to some pins. I used AP on them over the course of about 10 days, and was pleased to end up with a dense foil suspension. I filtered them and proceeded to dissolve the foils with a Sodium Nitrate based AR. When I dropped the gold, a nice brown sediment could be seen accumulating on the bottom of my flask. After a minute or so after adding SMB, I gave the solution a swirl, and poof, sediment gone and solution went from a clear jade green to an opaque amber. I added a pinch more of Urea and then a pinch of SMB and saw no immediate change. I figured the sediment needed time to settle so I left the solution untouched for an hour and returned to find a sheet of gold in its metallic form covering the surface of the solution along with a line about 3/8" thick of shimmering gold plate around the inside of my glass.

Any suggestions as to the cause of this floating? Any way to break the surface tension of the solution? I apologize for omitting parts of the process in my explanation, I will elaborate as needed. Thanks in advance everyone, I'm Phil btw.

 

[Lino1406]

It seems the urea-HNO3 complex floats with the gold

 

[anachronism]

Hi Phil

If you've plated the glass then you're going to need to dissolve it again from the glass I am afraid. For your floating gold I use a spray wash bottle set on mist and spray the surface. It breaks the surface tension and lets the gold settle.

Jon

 

[McGettums]

Thanks for the replies,

Time had it's way of showing me once again that patience is often the best approach in new ventures. I woke up in the middle of the night and found a nice layer of that ol' stuff that I like to see, formed on the bottom of my glass.

It's amazing how different two processes can be, i.e. fingers vs. pins, even when done using the same basic technique (AP)

Jon - I guess I'll be carrying the plating over to my next run, in what may have become my dedicated AR vessel.

 

[Platdigger]

As per GSP if you add your nitrate in small amounts, just enough to put the gold in solution, you won't need urea.
And if you do overshoot, you could use sulfamic instead.