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  1. #1

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    Should I purify/refine 925 silver for silver nitrate?

    I've read all the threads and precautions on making silver nitrate but the cost here in Israel is just too high to buy it (300$ for 100g or 200$ for 50g of silver nitrate for pure 99+% grade). There is nitric acid in our studio (for etching) and 925 silver (sterling?) can be easily obtained. A few questions before I begin:

    1. Can the nitric acid be warmed with bain-marie to haste the process instead of using a hot plate? This will be performed outside so having electricity can be a problem.

    2. Is 92.5% of silver nitrate enough for various alternative processes (collodion/salt paper/...) or should it be refined? I'm not planing on manufacturing Kodak grade products, just experimenting with old photographic processes.

    3. If it does need to be refined, what is the best/easiest way? Copper wire?

    4. On perfect conditions, one should use 75g of silver per 100ml of nitric acid to convert all the acid to H2O and NO (which converts to NO2 with air?). This should yield about 1.57g of silver nitrate per 1g of silver. Does refining silver yields a much lower values or roughly the same as pure silver in the solution?


    Thanks,
    Omer

  2. #2

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    Hello Umut,

    Forgot to mention it is not possible to order silver nitrate from abroad. The customs office allows only authorized labs to import such chemicals.

    Thanks,
    Omer

  3. #3

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    My school allows me to use their lab permission to order chemicals locally. No luck trying to get chemicals from outside...

    Actually I already have about 200g of 925 silver so with addition of nitric acid the school supplies it costs me nothing (but my health...) to synthesize silver nitrate.


    Omer

  4. #4
    Uncle Goose's Avatar
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    I've made my own silver nitrate with 99.9% pure silver, it's not a very difficult process and not that dangerous if you know what you are doing. First of all it's important to do it outside or in a fume hood. Second, wear protective glasses and gloves at all times when handling the chemicals. You don't need a bain-marie for heating up, a small bunsen burner or heating plate will do, just make sure you use a large enough beaker that is heat resistant because once the reaction starts it's exothermic and it gets really hot. You can use .925 silver but you will have contamination of Copper Nitrate (blue color), since copper nitrate does not crystallize easily you just have to wash your silver nitrate crystals a bit more till you got rid of the blue color and your fine. Don't store the crystals in anything plastic!! only use glass containers, otherwise you will be left with a gooey substance after a while.
    Sure, I could give you a boring explanation who I really am but I rather let the Origami do the talking.

  5. #5

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    I will be using Pyrex flask for the process and brown glass containers to hold the crystals. Is this OK?

    How should I wash the crystals? Silver Nitrate is soluble in water, if I wash with water, wouldn't it dissolve the silver crystals too?

  6. #6
    Uncle Goose's Avatar
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    You have to wash with Nitric Acid, not with water otherwise you will end up with no crystals. Just put your crystals in a coffee filter and use a funnel to pour Nitric Acid on it to get rid of the blue Copper Nitrate contamination. Pyrex should be more than fine and the brown glass is certainly OK for Silver Nitrate.
    Last edited by Uncle Goose; 11-24-2012 at 04:36 PM. Click to view previous post history.
    Sure, I could give you a boring explanation who I really am but I rather let the Origami do the talking.

  7. #7
    Uncle Goose's Avatar
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    The best thing is just to do it outside, let the reaction begin and then take enough distance. You could wear a gasmask but why should you? Once the reaction is running there is nothing you can or should do, there is no reason to be in the vicinity of the fumes.
    Sure, I could give you a boring explanation who I really am but I rather let the Origami do the talking.

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