Cyanide found in silver lot shipped to refiner

[Jinx86]

Recently shipped 3500 ozt of silver to my refiner, the batch tested positive for cyanide. Much of it was already poured into bars for assaying lots prior to purchase. My question is how do I detect cyanide prior to melting or shipping to my refiner. I cannot process the cyanide laiden material in my facility, but would either reject the lot or pass the incurred fees onto the individual sending the material. Also the affected batch would be much smaller and easier to deal with.

[FrugalRefiner]

I have no personal experience with cyanide, but I can't imagine it would survive melting. Other than the melted and poured bars, what other material did you send?

As far as detecting it, there are a number of commercially available test kits that should do the job. Google something like cyanide test or something along those lines.

Dave

[jimdoc]

Was there any cadmium detected?

[Jinx86]

No cadmium, though I have had issues in the past. This lot would have contained some large batches of jewelry some might have been silver plated or gold plated, also some gold plated franklin mint medals, these are the only items I could image it came from.

[Lino1406]

Cyanide test for alkaline solution: 1.Add thiosulphate, this converts cyanide to thiocyanate 2.Add Fe+++ ions, this will give redness by Fe(CNS)3

[nickvc]

Got to be honest I think your refiner is having a laugh, it sounds to me like your refiner is looking for ways to increase his margins, if the majority was pre melted bars the heat would have destroyed any cyanide and I can’t imagine the coins been a problem as they are struck then plated and rinsed, the plated jewellery would have been rinsed after plating to recover any gold solution.
As an aside I’d keep any gold plated silver aside and melt into individual bar or bars and get them assayed or if you refine use it for inquarting, the gold content should be a nice little bonus which I’m sure your refiner isn’t paying you now.

[Lou]

Ask them to tell you how it tested for cyanide, how much was found and what part of the lot.

[4metals]

Might also be good for our members to know what refiner is telling you this!

[Lou]

Even if it did test, the only thing he did was commit a very big shipping mistake.

Silver cyanide melts to pure silver quite easily with a bit of NO formation (which then becomes NOx, so it does need scrubbed from the flue gas).


Lou

[nickvc]

Might also be good for our members to know what refiner is telling you this!

[acpeacemaker]

Decomposition in the links
HCN
https://www.cdc.gov/niosh/ershdb/emerge ... 50038.html
KCN
https://www.cdc.gov/niosh/ershdb/emerge ... 50037.html
NaCN
https://www.cdc.gov/niosh/ershdb/emerge ... 50036.html
There is spot testing silver cyanide in Feigl, like how Lino explained.
Can also try googling Xray diffraction silver cyanide. These machines are costly.

[Jinx86]

Thanks for all the replies to this so far. I have been in Philadelphia for the ANA show for the last week and will have to give these replies a good read through.