Here is one for the experts here

[truthmatters]

Ok as of 6 am no further action from the remaining metal settled at the bottom. I poured off this solution and added 250ml HCL, no silver chloride dropped out. I took remaining solids added 200ml H2O with 200ml nitric action picked up again but only mild reaction, but with agitation helped it along. By 9am had completely stopped so added 75ml more nitric to get it going again. This last little bit is being very stubborn to get into solution. Question is this because it may be getting coated over somehow and requiring the nearly constant agitation and adding this much more nitric. With the amount I started with my initial 50/50 water nitric should have put this into solution if it was representative of the material i started with. So far I am assured that there was no Ag in metal sample but still attempting to get last of metal to completely dissolve into solution with difficulty.

 

[anachronism]

If you didn't get any silver Chloride then that shows that the XRF report of silver was wrong. I would respectfully suggest that it's therefore likely that the rest of the XRF report was just as wrong.

That given I would test your solution with DMG and see if you get a result from that but at this stage it isn't looking positive.

Jon

Edit: As an aside I use an XRF myself as part of my business and one made by the same manufacturer as the one of which you showed pictures. The comments on here about these reports having the potential to be wildly wrong are correct.

For some reason Rhodium "pops up" on readings with appalling regularity where there is no Rh present.

 

[g_axelsson]

Hehe, by "taking a sample" I meant a few gram, not 250. That's a lot sized sample.

The reason we take small samples are that we can tell if there is silver in a metal powder from a 5g sample faster than processing a 250g and with less chemicals used and less waste that needs to be treated in the end.

At least it is quite clear that there are no huge amount of silver (or led or mercury) in your material. You still have an undissolved part. Can you filter off and clean the remaining solids after it stops reacting with the acid. Then take a picture of it and let us have a look.

For the remaining undissolved solids I would start by adding (not much more than covering it) a bit of nitric acid (about 30% concentration, 67% concentrated nitric acid reacts slower than diluted acid). If there is a reaction or if the acid changes color then it still reacts with the nitric acid and more patience is needed.

When the sample doesn't react with nitric acid I would then add some HCl (add double the volume already in the beaker), this would create aqua regia and dissolve any remaining palladium, platinum or gold. Add it slowly as the reaction could get quite vigorous and create a boil-over.
If there is any precious metals in it a stannous test should reveal it. By the way, have you tested your stannous so it hasn't gone bad?

Göran

 

[truthmatters]

Hi Göran
My Stannous chloride is about 10 days old. The tin I used was from tin fishing weights but have since ordered some along with the DVD on PGM refining, still haven't received them in the mail. I could make up a new batch of stannous chloride if not in the mail today.
When it stops I will proceed as you have described. I am seeing a minute white substance forming in the bottom. Will get picture if possible.

 

[anachronism]

Ten days old is nothing - it'll be fine.

 

[snoman701]

Why not just add copper to the nitrate solution? If you get a precipitate, you can expect it to be a PGM, as you've already shown there is no silver in there. Given how concentrated the nitrate solution is, if it's there, it should cement.

 

[truthmatters]

I set the beaker from this morning on a glass shelf and took pictures of the grayish material settled in the bottom. You can still see a small amount of the base metal and the bottom is now covered with this gray matter.

 

[galenrog]

I’be been following this thread with some interest since it started. I noticed something that I have a question about. Truthmatters stated that he makes his Stannous Chloride with tin fishing weights. Since tin fishing weights I am familiar with are a bismuth/tin alloy, typically about 55/45, would bismuth have any affect on test results? Or are the fishing weight used pure tin?

 

[truthmatters]

All base metal has now gone into solution and this is whats left.

 

[truthmatters]

So my conclusion is this, as interesting as it was and for the knowledge I have pickup it has been priceless. As for what came out of the beaker regardless of what it happens to be, the cost of time and materials can in no way equal up to what value it may hold. Good and valuable lesson for myself and anyone else that may travel down this lonely road. To all who put up with me through the many days of this process, I thank you for your help and understanding. Your knowledge of these processes in unequaled to non other and a great resource for anyone wishing to dip their toes into refining PM's. I am looking forward to getting back to doing more refining again one day soon.
BTW any ideas of what I have in the test tube so I can label it for future use or does it go to the hazmat recycle?

Thank Bill

 

[nickvc]

I’d suggest to pour off the solution and then dissolve in AR and then test with stannous or if you have had enough of this project put it all in your stockpot.

 

[g_axelsson]

I’d suggest to pour off the solution and then dissolve in AR and then test with stannous or if you have had enough of this project put it all in your stockpot.

I second that, a test-tube with AR is a decent sized sample. It will tell everything about the possibility of precious metals with a stannous test.

As for the gray remnants, only small amounts of tin in a nitric solution could make quite a large volume of pale gray tin hydroxides. That is my guess on what it is.

It's been a bumpy ride this thread, but in the end we managed to get together and examine the material in a logical and scientific way. We all wish we have more gold than we do, but to be able to look beyond personal wishes and find the truth is a gain by it self, no matter what comes out of the beaker in the end.

I hope I didn't treat you too harsh, truthmatters.

Göran

 

[truthmatters]

Added AR and the gray substance went into solution, stannous test was neg for any PM
Thanks again
Bill