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  1. #1

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    Potassium Ferricyanide Keeping Properties

    Both as a powder and in solution, may I expect
    long life from the two? Dan

  2. #2
    David A. Goldfarb's Avatar
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    In solution it doesn't last long. I mix it up just before use. Dry it lasts.
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  3. #3
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    The powder lasts almost forever in a closed bottle.

    The solution of the compound alone lasts a rather long time as well. At least a minimum of 8 weeks to 16 weeks in my experience. If you add stuff it goes down.

    PE

  4. #4

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    How is it mixed?

    What are the dilution ratios for a strong solution and a weak solution. I attempted to use some for the first time this weekend and it did not go well at all.

    Jamusu.

  5. #5

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    someone may correct if I'm wrong, but Jamusu I believe a stock solution of say 100 grams/1000 milliliters can be made and you can use a 10% solution of this stock solution as a starting point.
    regards
    Erik

  6. #6
    David A. Goldfarb's Avatar
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    I put a few grains in a glass container and add water to make a pale yellow solution for local bleaching with a brush.
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  7. #7
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    Erik;

    That solution is a 10% solution. 10% of that would be 1% total. So, your answer could be a bit ambiguous.

    I should have been more specific above. If anything else is present it can be oxidized, and so typical rehal bleaches go bad because the bromide can be oxidized to bromate while the ferri can b reduced to ferro.

    PE

  8. #8

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    Yes PE, I guess my reply was a little ambiguous. I just meant to use the 10% stock solution and cut it by varying %'s to experiment with as a starting point to play with.
    regards
    Erik

  9. #9

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    Store soultions of ferricyanide in dark glass or opaque bottles, and away from light. Light, UV in particular, will break down the complex that holds the cyanide to the iron.

  10. #10
    Ian Grant's Avatar
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    Well to add to the confusion a 10% solution of Potassium Ferricyanide can last well over 2 years, stored well. I used some to make up a re-halogenating bleach last week. It's probable the solution was much older but it worked perfectly, and showed no signs at all of decomposition.

    As for the powder I have some that's at least 30 years old, and it's still fine.

    Ian

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