# Silver shot.



## GotTheBug (Dec 14, 2014)

I'm now thinking of redissolving this. Seems like I have a lot of impurities in the shot for the colors to come out like they did.
Fresh melting dish, seasoned, and melted with oxy-propane.
Would it be okay to run this in the cell or shoud I start over, wash the dropped powder better, and remelt?


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## etack (Dec 14, 2014)

looks like you have a lot of Cu in your silver still.

What did you do to it?

Eric


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## GotTheBug (Dec 14, 2014)

dissolved sterling, dropped with copper, washed with distilled water boil, dried and melted. I was thinking a lot of copper also.


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## Anonymous (Dec 15, 2014)

Did you dissolve in Nitric? As Eric says that is pretty dirty if you did? 

Can you post the full process you used so we possibly give you some tips to prevent this happening in future? It should be a lot cleaner than that. 

Jon

Edit here's a pic (for contrast and helpfulness) of the first silver we did using Nitric and a copper drop. We melted into a large silly lump though in a makeshift clay mold as we knew we would have to do it again later. :shock:


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## Palladium (Dec 15, 2014)

Excess nitric!


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## goldsilverpro (Dec 15, 2014)

Palladium said:


> Excess nitric!


Probably. And inadequate rinsing.


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## Palladium (Dec 15, 2014)

goldsilverpro said:


> Palladium said:
> 
> 
> > Excess nitric!
> ...



Lol. we think alike. I was thinking about it and came back to mention it and you already had. That's 99% of the time a reason people overlook without thinking about it.


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## GotTheBug (Dec 15, 2014)

Ah, I wondered if I was going to get the rolled up newspaper of love across the nose from Palladium. 

Yes sir that would make sense. Nitric is certainly a learning process, and yes I am being safe, well at least as safe as this hobby ever gets.

My sense of honor will cause me to start this one over and next pic will definitely be a much prettier one!

Thank You SO much guys, I would be nowhere without this forum.

Paul.


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## Anonymous (Dec 15, 2014)

Palladium could you explain the excess nitric thing please?


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## Anonymous (Dec 16, 2014)

No answer to my question? Well 24 hours later here's my take in the theory posited of excess Nitric.

Any excess Nitric will be used up by dissolving copper prior to cementing the silver. Copper isn't going to cement copper out into the silver unless electricity is involved (as in a copper cell) so gentlemen respectfully I disagree with your theory of excess Nitric. 

I'm open to be called out as wrong so feel free 8)


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## yar (Dec 16, 2014)

Could excess nitric be present if the cemented silver was not washed properly?


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## Harold_V (Dec 17, 2014)

spaceships said:


> No answer to my question? Well 24 hours later here's my take in the theory posited of excess Nitric.
> 
> Any excess Nitric will be used up by dissolving copper prior to cementing the silver. Copper isn't going to cement copper out into the silver unless electricity is involved (as in a copper cell) so gentlemen respectfully I disagree with your theory of excess Nitric.
> 
> I'm open to be called out as wrong so feel free 8)


It appears that you and I often are at odds over some matters, but I happen to agree with you on this one. I have no clue why excess nitric would discolor melted silver--but impure silver would certainly take on a fire coat, as is represented in the posted picture. 

The only thing that comes to mind, for me, concerning excess nitric might be that it would dissolve a larger amount of copper before permitting a cementing of the dissolved silver. That might be cause for a greater concentration of dragged down copper nitrate, which may not be fully rinsed out. 

One other thought occurred to me. If, for what ever reason, some copper oxide was included in the cemented silver, it most likely would NOT be rinsed out. However, a rinse in dilute sulfuric acid would most certainly dissolve the oxides, allowing them to be removed in the rinse cycle. 

Harold


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## Harold_V (Dec 17, 2014)

GotTheBug said:


> Would it be okay to run this in the cell or shoud I start over, wash the dropped powder better, and remelt?


Depends. If what you melted was silver cement, recovered on scrap copper, and you didn't use fine wire, whereby you may have left behind lots of partially consumed bits of copper, the material shown may be a good candidate for the silver cell. However, I'm troubled by the amount of fire coat I see. If you had melted the material in a crucible, along with some borax, it would most likely have removed the vast majority of the oxides, leaving behind a much cleaner silver. 

It is a mistake to use fine wire for recovering silver, for reasons I mentioned. It is also a mistake to use oxidized copper for cementing silver, as the oxides most likely will combine with the silver, especially if you don't flux well when melting. I also don't understand why you'd pour shot if your intended purpose is to part the silver in a cell. Pour a slab, with large surface area, one in keeping with the needs of your cell, or the one you intend to use. 

I used to melt my silver cement with borax, which was then poured to a cone mold. Once cooled, it would be freed of slag, then remelted to pour anodes. The surface of the melted silver did not display but traces of oxides, so it is my opinion that you are doing something wrong, as I never experienced the degree of oxidation I see in that picture. 

Harold


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## goldsilverpro (Dec 17, 2014)

I did pretty much what Harold did. Like he said, never, ever, use small wire. Flattened copper tube will work so so but, when it starts gets eaten up, it will sliver. Heavy copper rod is OK. Unplated, unsoldered, clean 1/4" thick scrap buss bar pieces long enough to stick up out of the bucket are best. In a bucket with 4 gallons of solution, I used 5 or 6 lengths of 1/4" X 2" or 3" buss bar about 14" long. It was left o'nite and was usually finished when I opened shop the next morning.

For the cell bars, I had 4 oiled cast iron molds that were 3" X 9" on the bottom of the inside. I poured just enough silver in them so it covered the bottom with no gaps. The bars ended up about 35oz each. It took 27 bars to fill my cell anode box.


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## Palladium (Dec 17, 2014)

Didn't realize their was a time deadline on answers. I don't know how to explain it in science terms, only from what i observe and my eyes see, but when you use excess nitric acid sometimes it will eat the copper first and then start precipitating silver out. Sometimes it will start to drop silver first and then the silver will start to go back into solution after a short time. I don't know if its an over concentration of copper in the solution that causes it. It could be occurring in the solution or on the surface of the bar where the chemical action is taking place. I'm not sure what the cause of it is, but i can see the proof in front of me when it happens. It might be like the ap process where once the solution is saturated it produces copper chloride, don't know. I do know it's green copper oxide specks trapped in the cemented silver. I could use sulfuric acid to wash it, but that would add an extra step to my process. Usually i'm doing 100 lbs plus at a time and having to go that route would create a lot of work and waste. I use BIG copper slabs for the cementing. I try not to deal with sulfuric acid except for removing lead from gold. Basically my work horse chemicals consist of Nitric, Hcl, urea, and smb. With that i can pretty much process anything gold or silver. When it happens that i have a dirty batch i just pass it over to the cell and deal with it there by adjusting the solution. The easiest way i have found not to deal with it is " Don't create it ", sort of like AgCl. Another thing i have observed that has me puzzled is that when i drop a large batch it may be 2 ft deep in the bottom of a stainless drum and after it sits and settles overnight nitric will gas from the sediment when you stir it up. This is after it has been dropped and washed 3 times. I've checked the solution several times for copper resides with ammonia and checked the ph of the solution for acids. Nothing! , but yet i get the red cloud of death. I can't explain it in either circumstance, but the fact remains it happens.


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## Anonymous (Dec 17, 2014)

Nope no deadline Palladium, my dry brit tongue in cheek humour obvious missed the mark there 8)

Edit:

I don't think we're miles apart from what you've written in your later post, and from what Harold and Chris have also said it looks like the copper slab approach seems to be the best way. The only times I've left copper in the cemented silver have been a result of flattened pipes "shedding" during the cementation as Chris pointed out. 

Jon


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## Palladium (Dec 17, 2014)

Brits !


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## FrugalRefiner (Dec 17, 2014)

I'll add one experience I had a couple years ago to this discussion. I cemented some silver from some silver braze once that came out with green copper bits in it. The feedstock was some leftover bits of low silver (5 to 15%) brazing rod from my HVAC contractor. It took a lot of nitric to get it into solution, as it was mainly base metals. I forgot to dilute the solution before I added my copper to cement the silver. I had obviously used too much nitric, because when I added the copper I got a fair amount of NOx gas. When the cementation was done, there were some green/blue bits among the silver cement.

I attributed the problem to some combination of:

cementing from a very dirty solution full of a variety of unknown base metals,
too concentrated a solution (I had not diluted it prior to cementation :roll,
too much nitric left in the pregnant solution,
my copper bar extended up out of the solution.

I still don't know what factor(s) caused the problem. I've not had it happen again.

Dave


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## Palladium (Dec 17, 2014)

Another time i have noticed it was when i use to heat my solutions to get a quicker drop using copper. It shows up worse then.


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## Anonymous (Dec 19, 2014)

Palladium said:


> Brits !



I know! Where would you be without us? Hahahaha aha hahaha ha haha 8) 8) 8) 8)


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## goldsilverpro (Dec 19, 2014)

I never experienced the same things that Palladium and the others have. Everything always worked the same even though I'm sure I wasn't perfect enough to hit the nitric on the nuts each time. 

To make a long story short, I think my success was mainly due to the dilutions. The 50/50 nitric was half water to start with and I always diluted it 50/50 again with distilled water before settling and filtering. After filtering, I put it back in the bucket and added the copper bars.

The same with aqua regia. I always diluted it 3 to 1 with tap water before filtering and I can't ever remember having any problems dropping the gold with a sulfite.

Another example. Awhile back, for about 4 months, I used stannous chloride at least 10 times every day. The gold bearing solution I tested was about 50% nitric. I put a drop of solution on a spot plate and added 1 drop of stannous chloride solution. It turned deep purple but the color disappeared in a second. I then tried adding 4 drops of tap water before the stannous chloride. The purple appeared and stayed for hours.

It's like diluting dulls the effects of the nitric considerably.


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## GotTheBug (Jan 16, 2015)

I got it now, and a big Thank You, especially to Palladium, for all the help! When I get enough I'll run the cell and see how the high amperage works out.

Paul.


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## GotTheBug (Apr 3, 2015)

I do believe I've learned a thing or two. Thank You all, and a special thanks to Palladium.




8.8 Troy ounces.


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## Palladium (Apr 3, 2015)

Nice !
Money !!!!!


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## GotTheBug (Apr 3, 2015)

Thank You Sir, couldn't have done it without you.


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## kadriver (Apr 6, 2015)

Nice looking silver Crystal!


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