% Silver recovery from Sterling??

[mikeinkaty]

When using Nitric acid to disolve and copper to precipitate out the silver, what % of the pure silver available can one expect to recover?

Mike

 

[NobleMetalWorks]

When using Nitric acid to disolve and copper to participate out the silver, what % of the pure silver available can one expect to recover?

Mike

If you are doing everything correctly you should be recovering all the silver you dissolve into solution, matter of fact, you should be recovering everything you dissolve into solution, even the copper you cement out the silver with.

Scott

 

[mikeinkaty]

When using Nitric acid to disolve and copper to participate out the silver, what % of the pure silver available can one expect to recover?

Mike

If you are doing everything correctly, you should be recovering everything you dissolve into solution, including the silver.

Scott

Thanks Scott

 

[nickvc]

Bear in mind that most sterling will be below the 92.5% that it should be, this can be caused by solder or by the material not been plumb so if your getting 91.5% or better your getting all the silver that was there, to test for any silver left over from cementation take a small sample of the solution and add either hydrochloric or table salt, if you get a white precipitate it's silver chloride so it needs further cementation to remove the silver from the solution.

 

[mikeinkaty]

I've been making Sterling cornflaks and one of the batches I melted had some crud in it. Must have been some ferrous material in it from something. I picked through it and got out all the sterling flakes. I can't think of anyway to get the cruddy stuff out other than picking it out by hand, or, do a better job cleaning the sterling before melting.

But, what if the crud gets into the nitric acid bath? Will it disolve and go through the filter after dropping the silver? How is the best way to deal with it?

Mike

 

[nickvc]

Mike try to keep as much crud out of any refining process you can but with the idea that you intend to use your silver for either inquarting or for dissolution and then cementation it shouldn't really matter so long as you filter the solutions produced. The acids will either dissolve the crud or it will remain in your filters as solids and both processes are really recoveries rather than refining and will need further treatments to produce fine metals.

 

[etack]

What does crud mean? could it have been filled or weighted? do you have a lot of it?

Eric

 

[mikeinkaty]

What does crud mean? could it have been filled or weighted? do you have a lot of it?

Eric

Crud - as in unusual dark brown or black looking gritty stuff. I notice some small pieces weren't melting in the silver pool. After I put in Borax they turned to small pieces of rusty looking 'crud'. That's why I thought they were probably small pieces of steel. On hindsight, I could have probably picked them out if I would have had a pair of tweezers. They were not weighted pieces. One piece was a broach that probably had a steel pin on the back.

Mike

 

[etack]

Thanks for the answer helps to know what you are working with sometimes.

Eric

 

[mikeinkaty]

Would soaking my silver cornflakes in HCL disolve the loose ferrous material? I did a little test last night and HCL does not react with AG but does react with a small piece of steel.

Later edit - I now have 1000 grams of sterling conrflakes soaking in warm 31% HCL diluted with an equal part of water. There is a very small reaction takin place probably from non-sterling stuff in the flask. I'm going to let it set that way for a couple of days. Last nights test had no reaction with a couple of sterling flakes. I will run the acid through a filter and follow up with a couple of rinses with boiling water. Not that the filter would be necessary but I want to see if anything is caught.

By the way, I've been cleaning copper pieces with 31% HCL then a buff with a wire wheel. Will use those for later for dropping of the silver.

Merry Christmas everyone!

Mike

 

[mikeinkaty]

After 24 hrs I removed the silver from the HCL. They were squeeky clean and bright and all bubbling had stopped. Wasn't much bubbling- had to tap the flask to get 2 or 3 bubbles to rise. After 8 hrs no bubbles were rising. The weight had not changed at all. I flushed them couple of times with boiling distilled water and now have them dry and sealed. The filter paper caught a very minor amount of small non-magnetic grit.

Oh, here's something I did. I put them in a plastic folgers coffee can/lid and with a rare earth super magnet and shook them around. That found nothing.

Mike