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I determined the silver composition from an alloy obtained from a jeweler to be 55% and wanted to extract silver out of it. However, upon melting around 5 kgs of alloy, the silver composition went up to 57%. I noticed similar increase for another 2 times (different alloys of silver, i.e. different samples)

Could it be something related to oxidation/reduction of silver or any metal resulting in the increase in composition while in the furnace?

What are some of the analytical tests out there I could use to accurately determine the elemental composition and the compounds present in the original alloy vs the one just after melting it?

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closed as too broad by Mithoron, airhuff, Todd Minehardt, a-cyclohexane-molecule, andselisk Jan 7 '18 at 9:34

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

  • $\begingroup$ How have you been determining silver content before and after? $\endgroup$ – andselisk Jan 6 '18 at 17:18
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    $\begingroup$ I had them determined by a jeweler. I guess he used acid-base titration to determine silver. Almost all of my jeweler friends get the composition determined from them. $\endgroup$ – RBM Jan 6 '18 at 17:21
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    $\begingroup$ I find it hard to tell what exactly may cause this without knowing the approximate composition of the alloy and how silver has been quantitatively analyzed. It might be degasification of some impurities, or melt fractionation in the crucible, or something entirely different. $\endgroup$ – andselisk Jan 6 '18 at 17:29
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    $\begingroup$ Gravimetric analysis might still work at jewelry level. I do not not how jeweler work but refinement in the crucible as suggested is a possibility. Link on silver in alloy are easily found one is strippolichemistry.weebly.com/uploads/9/7/8/2/9782140/… $\endgroup$ – Alchimista Jan 6 '18 at 17:51
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    $\begingroup$ I believe most jewelers in my town quantify silver using both gravimetric analysis followed by the Volhard method which involves back titration of silver nitrate. $\endgroup$ – RBM Jan 6 '18 at 18:05
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Zinc is used in some silver alloys; Zn would be easy to lose into dross or vaporization.

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  • $\begingroup$ I am so sorry I posted the question incorrectly. Actually, I noticed a 'decrease' of 2% and NOT the 'increase.' The composition of Ag went down to 55% from 57% Do you have any insight as to why that might happen? $\endgroup$ – RBM Jan 7 '18 at 4:52

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