# Silver Epoxy



## thalx (Jun 16, 2019)

Greetings,

Recently I have gained access to the silver epoxy waste stream from a manufacturing process. The quantities are small but will continue for the foreseeable future.

My question relates to the types of material and the initial processing. The most applicable topic I found on the forum was entitled "Silver Powder in Nitric Acid" except that this topic starts after the epoxy was removed from the silver. (There was another thread that applies to the search string "Silver Epoxy", but the content was much less technical in nature.)

In the material stream I have, there are essentially four types of material present. I also know that the recommendation is to incinerate first. Here is a picture of the four types of materials present:




-1) Dixie Cup (paper, wax) with cotton swabs (wood, cotton) and/or tongue depressors (wood)
-2) Paper towel wipe (paper)
-3) Aluminum mixing cup with large wad of cured epoxy (aluminum)
-4) Syringe with remnants of epoxy (plastic & rubber)

-1 and -2 (paper, wood) I expect will incinerate well. -4, the plastic and rubber syringes will be very stinky. My big question is to -3, the aluminum mixing cup. It does not separate well mechanically due to the epoxy getting deep into the folds at the sides. My gut tells me that sodium hydroxide would remove the aluminum easily; but rather than get experimental I decided to consult the experienced folk for guidance.

So my question is really this: should I incinerate it all together, or is it better to get the aluminum out first? 

Thank you in advance.

-Chris


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## FrugalRefiner (Jun 16, 2019)

With any new material, I would tend to keep the different types separate at first until I determined if each type was worth processing. The paper towel wipes may or may not be worth processing. I would disassemble the syringe and try to collect all the value containing material onto something easier to incinerate, like paper towels etc. At the least you should be able to cut away most of the syringe and incinerate just the ends.

Once you have processed some test batches, you can determine what is worth chasing.

Dave


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## Lino1406 (Jun 16, 2019)

Prior to incineration: Plastic syringe - to be trimmed to the silver edge, sometimes silver can also be squeezed.
Aluminum - NaOH as said


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## rickbb (Jun 19, 2019)

Is there a solvent that will dissolve the epoxy? 

Do you have access to the MSDS for the epoxy to find out what it may contain before you try to incinerate? Burning it could be much worse than just being "stinky".


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## nickvc (Jun 19, 2019)

One has to say unless the volumes are large, with the current silver price a waste of time and effort if your looking to make money, but could be educational :shock:


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## Lou (Jun 20, 2019)

We spread it out and incinerate it in large stainless pans at 600 C overnight. We then melt it up and cast into bars and off to some other refiner at this point. Don't have the time to refine it in a cell. 

Lou


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## thalx (Nov 29, 2020)

Greetings,

Quick update to this thread. The expected high volumes of this scrap never materialized, as the fab shop changed their processes to lower the assembly cost. The product being used: AA-DUCT 906 from Atom Adhesives. It's described as a low-cost silver epoxy, consisting of silver-coated ceramic particles. Today, the price on the company website is $550 USD for 500 grams ($1.10 USD per gram) 

Perhaps this is not the best choice for a first attempt at silver refining. Will keep searching for a different opportunity. Thanks all for your kind advice.

-Chris


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## Lou (Nov 29, 2020)

Thanks for the update.

I wouldn't be too discouraged but at the same time, I'd consider that the material can still be easily recovered, albeit more expensively.


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