How to get PT from AR solution

[nickjam]

Hello everyone:

I processed 3.5 pounds of gold plated pins in a sulfuric acid cell. I then took the resulting black powder that settle after leaving it alone for a few weeks and placed it into HCl/Cl almost 100% of it dissolved and I got a orange/red solution!?! I filtered it 3 times and after I left it for a week (time constraints) it had returned to yellow and there was a white precipitate on the bottom. I filtered that twice and had a nice clear solution!

When I did the SMB drop it was beautiful. I got millions of these tiny. shiny. gold particles dancing inside the beaker. I let them settle and decanted off the remaining liquid. Still yellow, I tested for gold and I got the orange of PT metal.

I don't know where I could have picked that up in the process, but:

1) How do I drop this out of solution? Asking because I am after gold not PT.

2) Is there a secondary test to ensure my Stannous Chloride is not giving me a false positive?

Thanks!

 

[anachronism]

Why do you think you have Pt from gold plated pins?

 

[nickjam]

I was testing to ensure I did not have any gold left, with Stannous Chloride. I placed a drop on a white, clean, plastic surface and the drop turned an orange color instantly and orange brown after about 30 seconds. It will stay that way for about an hour then turns black.

 

[anachronism]

Thanks Nick

"False positive" for gold with stannous chloride is an incorrect term. If it's black it's gold still in solution. If it's brown then it's not. Make sure it's not a browny colour rather than an orange colour can you let us have a picture?

Jon

 

[kurtak]

My "guess" --- your seeing the "false positive" often talked about here on the forum when more SMB is used then needed to drop your gold

Kurt