White Stuff in my Silver Oxide ?

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K

kurt

Well-known member
Joined
Feb 15, 2011
Messages
537
Hi All – I’m new here. I have been experimenting with the PM recovery & refining process now for about 1 year (mostly from circuit boards)

I just dissolved a bunch of electric motor contact switch point in nitric – precipitated with sodium chloride & then put the sodium hydroxide (98 ½ % crystals) in. The vast majority of it turned to the black silver oxide but I also have a small amount of a white kind of pasty stuff in it that smears against the glass when stirring.

So – What is it? Is it a problem? If so – any solutions?

Thanks from Kurt - & by the way – Great forum – wish I would have found it a year ago – instead of just a few weeks ago
 
Yes - I soaked in thinner to get rid of most of the oils & grease & then put in a basket & got it all red hot with the tourch. Also did only the non magnetic ones in this batch
 
Maybe i should say - it doesn't smear onto the glass - but when stirring if I bring it up against the glass it acts like a gooy substance that acts smeary
 
It is in fact silver chloride.

the AgCl lumps are converted to oxide on it's outer 'shell', once you smear then on to the glass you expose the inside of the lump which is still... well... AgCl.

When i experimented with this process i used magnetic stirrer, and let it run whole night before adding glucose/sugar. This to ensure full conversion to oxide. (Though i'm not sure i really did managed to fully convert it to oxide, maybe 99%)
 
samuel-a said:
It is in fact silver chloride.
Click to expand...
Do not be so sure, often these points are soldered in place with lead. Lead will go into nitric the same as silver, both yielding a clear solution if no other elements are present. Lead will also form a chloride that is very similar in appearance to silver chloride (I cannot tell the difference visually). The best way to tell the difference is that the silver chloride will turn dark purple/black in sunlight, and lead chloride will not.
 
Thanks for replys - lead from solder was my suspect. Any way to deal with it at this point?
 
Oz said:
The best way to tell the difference is that the silver chloride will turn dark purple/black in sunlight, and lead chloride will not.
Click to expand...

This will be interesting... and hopefully kurt will do this test.

Still, I stand behind my statement.
I've expirienced similar phenomenon with leadless AgCl covertion.

I'm not stating that he have or don't have lead with the AgCl, just saying that it takes time to get a full convertion to oxides, and when the inner part of the lumps smears against the glass it exposess un-converted salts (wather it is Ag or Pb) and most likely the majority of it is in fact AgCl.
 
Hi guys - & again thanks for the in put – but I am a bit confused – based on info I have read (before finding this forum) when you dissolve silver in nitric you get silver nitrate. Then when you add sodium hydroxide you get silver oxide which is then converted to pure silver with karo syrup (or other reducing sugars)

So don’t quite get the silver chloride reference. – from other stuff I have read here on this form – you want to stay away from making silver chloride as its hard to deal with.

At this point it is still sitting in sodium hydroxide & still has the white stuff in it.

A while back – as my first experiment with silver – I dissolved about a ½ gram 925 earring with similar results – but here I am guessing I have about 1 ¼ oz & though it may not be a problem thought I would ask before proceeding as this is my first real go with silver.

The last year I have mostly been working on the recovery of gold from circuit boards (refining that is next)
 
Sam,
I am not saying you cannot have something that looks simular even when converting pure silver chloride, as complete conversion to the oxide can be dificult. But what I am saying is that given Kurt’s source material lead chloride is likely. If you had 90% silver chloride and 10 % lead chloride that had been treated with NaOH and had even achieved full conversion of the silver chloride to the oxide, you would see what Kurt is. I can’t say for sure if he has converteted all of his silver or not, but given his scrap source I would be amazed if he does not have some lead chloride present.

kurt said:
I just dissolved a bunch of electric motor contact switch point in nitric – precipitated with sodium chloride & then put the sodium hydroxide (98 ½ % crystals) in. The vast majority of it turned to the black silver oxide but I also have a small amount of a white kind of pasty stuff in it that smears against the glass when stirring.
Click to expand...
Kurt, you created your silver chloride when you added sodium chloride (table salt) to your silver nitrate, that is what you precipitated. You are right that silver chloride is dificult to deal with as you are finding out. In the future in this case you should have cemented your silver on copper. This would have given you silver metal and left your lead in solution.
 
Oz – Sam – again, thanks for your in put

Oz – guess I wasn’t awake yet when I posted my last post – the silver chloride thing dawned on me later at work. (daaa) Anyway – I went with the salt, lye, sugar method because I didn’t have any large copper source at the time. Just fine stranded wire. --- & wouldn’t you know it – the next day (after I precipitated with salt) A guy that I get stuff from, brought me 2 big circuit breaker panels with large uncoated copper bars in them so now I have about 8 lb of heavy copper.

The thing is I just bought a 15 gallon barrel of 52% 36 degree nitric for $175 but I need to empty it & return it in 3 weeks – or pay a $250 deposit on the barrel. – I just stripped about 400 lb of green board circuit boards – have about another 100 lb of green board & about 600 lb of brown board to strip & some other mis. PM scrap to process.

I have 2 – 4 gallon glass wine making bottles so can pour off 8 gallons for future use – so need to use up 7 gallons so I can return the barrel. – So not having the copper & limited time to use up nitric is why I went with the salt, lye, sugar method on this batch.

Sooo – now that I have silver oxide with white stuff in it (could be lead – could be silver chloride that’s not converting) what do I do about it?

Ether way – can I just move on to the sugar step in the process – then re dissolve & cement out with copper (now that I have it) --- OR ???

I have a “lot” of stuff to process & have access to a “lot” of stuff – so I am here to “learn” --- So far – I have been working off the tons of miss information & incomplete info out there on the web. – wish I would have found this forum a year ago!!!

Kurt
 
Silver chloride is insoluble in very hot water, lead chloride is fairly insoluble in cold water, but lead chloride become's much more soluble in boiling hot water.

Try adding your powders to a pot of boiling hot water, stiriing well, if some chlorides in solution lead will dissolve (could add a touch of HCl if you need, and then convert silver back to oxide with hydroxide later).

Give silver chloride time to settle, decant solution to another vessel while very hot, if lead chloride will precipitate white powder in liquid when cooled.

The volume of hot water will help either way if lead or not.
 
Thanks butcher - I will give this a try & post back the results _ may be a couple of days though depending on how long it takes me to do some other things I have going on.

In the mean time I am open to any other in put on the matter

Kurt
 

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