# Anyone refined Silver Solder 15%?



## bmackay (Jun 16, 2011)

Hey everyone,

I have about 20 pounds or so of high grade solder that contains a 15% pure silver alloy. 

Has anyone tried to refine it? 

Here is a link for those who don't know what it is:

http://www.harrisproductsgroup.com/en/Products/Alloys/Brazing/Phos-Copper/Stay-Silv-15.aspx


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## samuel-a (Jun 16, 2011)

bmackay said:


> pure silver alloy.



Oxymoron :shock: 
(sorry, i had to) :mrgreen: 


other then that' seems pretty stright forward, dissolve in nitric, cement with copper.
I can't see how phosphoric acid will interfere the process.


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## Oz (Jun 16, 2011)

You should be able to sell if for more than its silver content value as silver solder. You also avoid nitric and waste removal costs.


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## qst42know (Jun 16, 2011)

Being able to site the brand and the alloy should make it easy to sell for far more than the silver content.

On another note and just out of curiosity. Is a 15% silver content high enough in silver to inquart a pgm bearing gold? If not what would the limit be, sterling, coin?


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## samuel-a (Jun 16, 2011)

Hi qst42know 



qst42know said:


> On another note and just out of curiosity. Is a 15% silver content high enough in silver to inquart a pgm bearing gold? If not what would the limit be, sterling, coin?



If memory serves my right, silver content should be higher then 50% of the alloy.
With PGM content no higher then 10% .

Please correct me if i'm wrong.


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## Oz (Jun 16, 2011)

qst42know said:


> On another note and just out of curiosity. Is a 15% silver content high enough in silver to inquart a pgm bearing gold? If not what would the limit be, sterling, coin?


It depends on what the silver is alloyed with. If it was 15% Ag and the balance just copper you would be ok, but you will consume about 3 times the nitric digesting your inquart. The lack of silver will also mean you will not be effectively removing PGMs from your karat gold into a nitric solution. Technically speaking some of your higher karat golds are a silver alloy of 10-15%, balance Au.

Personally I would not want to use a lower grade silver than .925 sterling or .90 coin for karat gold inquartation.


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## qst42know (Jun 16, 2011)

I figured there was "some" margin to work with but wondered where the boundary actually was. 

Is this PGM dependant, as in the percentage of PGM under a certain value, 90% silver is ok? 

Has anyone had to inquart a second time, or is once plenty?


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## oldgeek (Jun 16, 2011)

bmackay said:


> Hey everyone,
> 
> I have about 20 pounds or so of high grade solder that contains a 15% pure silver alloy.
> 
> ...



So how much do you want for the lot? I do HVAC work, and you would be far better off selling it than refining it.


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## Harold_V (Jun 17, 2011)

qst42know said:


> Being able to site the brand and the alloy should make it easy to sell for far more than the silver content.
> 
> On another note and just out of curiosity. Is a 15% silver content high enough in silver to inquart a pgm bearing gold? If not what would the limit be, sterling, coin?


You can safely look at the answer to this question by assuming that you'd inquart with something other than silver. The percentage of silver isn't critical, it's the overall percentage of gold/platinum that is, and what the balance of the base metals are. Needless to say, you wouldn't want to use lead or tin------but most copper alloys (which is what this solder would be) are perfectly acceptable. In fact, using the solder for inquartation would help justify the use of nitric ---where you must use a non-ferrous base metal of sorts, anyway, so it may as well be something that must be dissolved in order to recover the values. Remember---silver is not a requirement for inquartation---although it's highly desirable because of the low consumption of nitric, and becomes the carrier of most of the platinum and palladium. 

Harold


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## Harold_V (Jun 17, 2011)

qst42know said:


> I figured there was "some" margin to work with but wondered where the boundary actually was.
> 
> Is this PGM dependant, as in the percentage of PGM under a certain value, 90% silver is ok?
> 
> Has anyone had to inquart a second time, or is once plenty?


 
Are you clear on the reason for inquarting? 
The reason I ask is once you have parted the precious metals via inquartation, there is nothing to be gained by parting them again. The sole purpose in inquartation is to permit breaking down an alloy that is, otherwise, impervious to acids. Take note that major refiners do not inquart--they digest directly by AR, by simply balancing the input to insure that silver content isn't excessive. 

Harold


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## Oz (Jun 17, 2011)

Well, I read qst42know’s follow-up question (as to PGM concentration vs. silver percentage required to remove it) earlier this evening, and did not reply. Frankly because if I understand what he is asking correctly, I did not know how to answer him properly. Here is why. 

Platinum cannot be digested by nitric acid alone, unless it is alloyed with silver. To me that seems to indicate that intimate contact is required between the 2 elements. Now if you use a 15/85 alloy silver/copper, that will not happen efficiently. It will spread out the gold so you get a good sponge gold after nitric removing your base metals, but the PGM removal I think he is asking about is a different animal. 

Typically I inquart with cement silver, but have used coin and sterling without having difficulty in PGM reporting in my gold. I lack ICP or XRF so I have never taken this further than proving to myself that what I was doing was effective. 

Some may find of value one of the first conversations 4metals and I had on this subject. He “does” have fancy toys to test with. http://goldrefiningforum.com/phpBB3/viewtopic.php?f=49&t=5469&p=46906#p46906 

In short, if your desire is to alloy down karat gold for a nitric digest, silver is best in terms of nitric consumption. If nitric is cheap for you and no silver is handy, copper will do the job of alloying down your karat gold. If you are concerned about removing PGMs from karat gold I would use cement silver, however I have found that coin and sterling silver perform satisfactorily. 

QST, a great question, but you need someone slicker than me to give you ratios or percentages as to how far you can push this. 

I would love hearing an actual chemist chime in as to how silver allows Pt to go into nitric.

EDIT; if you have more than 1 part in 10 PGM/silver in your inquart, you very possibly will leave PGM with your gold in an inquart. I would stick with 1 part in 20 to err on the side of caution. Before you ask, this is not a problem using silver with karat gold even if it is white gold. Reuse the same silver more than once without removing the PGM content though, and yes it could be a problem.


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## qst42know (Jun 17, 2011)

This silver solder clearly has a useful value beyond it's silver content.

What I was getting at in a not completely clear fashion is, If one wanted to recover the silver from this solder, the usual advice is digest in nitric cement, etc..

However if you had both solder to recover silver from, and a karat gold alloy that was merely too high in silver for AR you could get double duty from the single batch of nitric, using the solder to inquart (providing the solder had no tin). 

This plan should work for simple AuAg alloys but falls apart at the alloys containing the platinum group especially when the balance point is unknown.


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