[Athiril]

Ascrobic Acid + NaOH is a basic photographic developer and reduces silver halides (silver bromide etc) to metallic silver.'

I made a particularly caustic solution of it, and put some of my many off cuts of film in there, which first develops the film (silver turns black) and quickly removes it from the film base, leaving clear plastic behind, and an opaque very dark grey solution.

Only a very minute amount of the solution doesnt filter through filter paper.


I think I should be able to evaporate all liquid, then dissolve the ascorbic acid in alcohol (methylated spirits), filer that off, then put the rest in a water solution, which should only leave undissolved silver (in whatever form) since it shouldnt be able to dissolve without the ascorbic acid... sound about right?


Anyway, what current form is the silver in?

I do not think its silver oxide, as adding ammonia to a small test sample doesnt turn clear, though I could be wrong.



I dont think I'll be able to get nitric acid any time soon, maybe a few weeks, so this is my best bet at being able to recycle silver by dissolving it and trying to end up with a silver halide product I can mix with gelatin to make a photosensitive emulsion.

[Borek]

If you have metallic silver it won't dissolve without strong oxidizer (or strong complexing agent - then air oxygen can be enough).

[Athiril]

Its certainly dissolved - the solution started clear, its now opaque with the amount of silver in it - it filters through paper.

The original film used is completley clear, just the acetate left behind.

[Athiril]

It reacts with potassium permangnate weak solution to turn from pink/purple to a sort of yellow colour, so logically I think its still metallic silver, permanganate should take it back to a halide..

[Borek]

If it is opaque, you have a suspension of a very fine silver.

Permanganate can decompose (to MnO₂ and O₂) by itself, it doesn't need reducing agent for that.

[Athiril]

The reaction for that was virtually instant.

I've done some more work, and found that both copper sulphate and magnesium sulphate solutions precipitate it.

It's clear, apart from the precipitate, I decided to go ahead with magnesium sulphate, ascorbic acid doesnt precipitate in it, sodium hydroxide does, but its a very clean white, my precipitate isnt a clean white, and there is a lot more of it than just could be attributed to amount of sodium hydroxide used - at least thats how it seems to me - as it either has to be in the precipitate or dissolved.