# Recovery amount is off



## Gwar (Feb 28, 2022)

Hello, I started a new batch Friday in preparation of my new crucible (which never arrived), I started with 104 Canadian dimes (1953-1967) that are 80% silver, my math was that I could possibly recover anywhere from 5-6 ozt, I put the coins into the glass container and added 200ml of H2O distilled and 200ml HNO3 to start, after about an hour I added the exact same amounts again, after the reaction had taken place and things were done I let the solution cool and added 300ml of H2O distilled to dilute, filtered and started to add the copper rods, what I had noticed right away is that there were crystals in the bottom of the container used to melt the coins, I guess I didn't clean the receptacle as well as I had thought from the previous night of making AgNO3 (Silver Nitrate), the other odd thing is that this time all of the coins were gone, nothing left whatsoever, last time I had small metal discs remaining.. I was getting a good reaction from the copper and cement and as I was stirring there was a lot of perhaps Copper Oxide ? or a floating substance that was very noticeable, I cemented as much as I could but started using different jars after filtering to prevent contamination and kept them separate from the good first cement jar, I used the copper rods in those containers and again I was getting more of the gunk surfacing to the top, the rods looked like they were getting covered in cement but it was the same pesky contaminants, my recipe must be off or I am making a newbie error, but after all was said and done I yielded less than 3ozt, I have kept the solutions in the jars and am considering another method to try to reclaim any leftover silver, perhaps like Silver Chloride, but all of the videos are a bit sketchy as to an exact formula, I did read a few threads and also there is no direct method that I am aware of or I might be searching with the wrong terms any help would be most appreciated, I also believe that I need to use a different size of copper that is submersible, any comments or advise would be greatly appreciated thanks for taking the time to read the thread, Mike


----------



## nickvc (Feb 28, 2022)

Your expected recovery is off from 104 dimes each weighing 1.7 grams you would be looking for 4.5 Troy ounces , I think you need to have more copper exposed to your solution to cement the rest of the silver out.
General opinion is not to process coins as they come already in a form that’s easily identifiable with a known silver content.


----------



## kurtak (Feb 28, 2022)

Gwar said:


> I was getting a good reaction from the copper and cement and as I was stirring there was a lot of perhaps Copper Oxide ? or a floating substance that was very noticeable,


That is not copper oxide - it is just very fine/small particles of cemented silver that have clumped together with enough air trapped between the particles to make it float

Edit to add; - though there may be some but not a lot of copper trapped in it also 

Kurt


----------



## Gwar (Feb 28, 2022)

Thanks for all the replies !! I will proceed and see what happens !


----------



## Gwar (Mar 22, 2022)

I think I was using the wrong size of Copper, it was thin as 12 gauge wire, I am using a thick 4 inch by 1/8th inch by 14 inch bar, what a difference..


----------



## Gwar (Mar 22, 2022)

When I put the new copper bar in and as it is cementing..


----------



## Martijn (Mar 22, 2022)

kurtak said:


> That is not copper oxide - it is just very fine/small particles of cemented silver that have clumped together with enough air trapped between the particles to make it float
> 
> Edit to add; - though there may be some but not a lot of copper trapped in it also
> 
> Kurt


I get those floating blobs when there is free nitric left.


----------



## ssharktu17 (Mar 24, 2022)

what was the weight of the dimes?


----------



## ssharktu17 (Mar 24, 2022)

nickvc said:


> Your expected recovery is off from 104 dimes each weighing 1.7 grams you would be looking for 4.5 Troy ounces , I think you need to have more copper exposed to your solution to cement the rest of the silver out.
> General opinion is not to process coins as they come already in a form that’s easily identifiable with a known silver content.


1.7 grams if they were perfect mint condition.


----------



## nickvc (Mar 25, 2022)

ssharktu17 said:


> 1.7 grams if they were perfect mint condition.


That’s very true I was just pointing out that his expected yield was too high to stop him wondering where the rest of the silver was when he had it all


----------



## 4metals (Apr 8, 2022)

Surface area of the copper is critical because successful cementation requires the solution containing silver to contact the copper. This is why a combination of surface area and agitation (like a small aerator) gives the best results. 
Also continue until the solution tests negative for silver. All you need to test is a small glass of chlorinated tap water and a stir rod. Dip the stir rod into the solution and allow a drop of blue liquid to drop into the chlorinated water. If there is no silver in solution the drop will dissipate and remain clear. Any silver in solution will produce a white haze of silver chloride which is quite easy to detect visually.


----------



## Gwar (Apr 8, 2022)

Thank you 4metals, on a side note I just built this based on your Youtube video that FrugalRefiner was kind enough to provide a link to the video in a thread !!


----------

