Silver Extraction from Old Negatives

ADK

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I've searched around the net and haven't found too much information for extracting silver from old photo negatives. I have found that in some cases a cyanide solution is used, which I'm not interested in playing with...

I've also read that the average extraction rate is 9 g / kg of negative.

Does one of my PM friends have a safer method for extracting silver from old negatives?

Thanks!

ADK
 

DCFusor

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I can think of a number of (reasonably safe) ways...but I've not tested any of them. Got any negatives to donate to the cause?
 

ADK

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I knew you would be the guy to know! :)

I was approached by a friend who knew I was into re-sale of items and asked if I knew the best way to sell some silver... I said, "sure!"

Then he said that it was in negatives! Which led to this thought process...

I think that, right now, he is going to take a look at the subject matter of the old negatives (from a printing shop) and try and sell them as "vintage" negatives per my suggestion. I think he can get a lot more value from them sold as vintage negatives or craft items, etc., than he can make by reclaiming the silver.

He has a lot of negatives (pun may be intended...) but he would need about 3.5 kg of negatives to get 1 troy ounce of silver. I'm betting that the cost and hassle to pull out the silver would drop the value well below $10/3.5 kg of negatives.

Anyhow, if I can get a chunk from him at some point for free :) how much would you need?

ADK
 

ancona

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BTW,
You can google search "We buy old X-rays" or "X-ray recycling" and there is a lot of competition for your business.
 

DCFusor

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If they're old, they are probably cellulose, which is dissolved by quite a number of organic solvents. Dissolve them, filter the result, bingo - silver powder in your filter.

To test that would only take one. To do a large number cheaply, the trick would then be to recover your solvent with a distill/condense rig (which I have).

That's one way. There are others. It depends on how old, and how they built the emulsion. If the silver is on top, it's even easier - use acid to dissolve the silver, then precipitate it out later. Probably cheaper/less hassle in bulk.
 

ADK

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Thanks for the links and the comments... I'll get an assessment of the total weight of negative that he has and let you know how it goes, or maybe send some to you for samples (DC).

It sounds like they have quite a few from an old litho shop. I'm not quite sure what era, though. Likely 1960's.

ADK
 
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