LifeisElemental - 2-12-2020 at 00:19
Hi there,
I would like to dispose of ~20g sodium cyanide I have which I no longer would like. I would readily give this away to a responsible, trusted-user here
who has need for it(and please contact me if you are interested in a pick-up in MI) but, otherwise, is there any particular recommended methodology
that would be ideal for the safe quenching of this amount of NaCN?
I'm currently thinking of quenching it by dissolving small amounts at a time in NaOH solution, making a 5% aqueous solution, and adding this to an
excess of bleach outdoors informed via. the following:
http://www.sciencemadness.org/talk/viewthread.php?tid=24107
https://www.finishing.com/296/44.shtml
https://www.911metallurgist.com/blog/cyanide-destruction-hyp...
Any other thoughts - how long this quench might take, potential other hazards to consider, etc?
[Edited on 2-12-2020 by LifeisElemental]
[Edited on 2-12-2020 by LifeisElemental]
woelen - 2-12-2020 at 00:35
If you really want to destroy it, just dissolve it in 200 ml of water with a teaspoon of NaOH added (do this dissolving outside) and mix with a liter
of household bleach. Put this aside for one night (again, outside) in a loosely capped bottle. After one night, you can flush all of it through the
toilet. The bottle must be loosely capped, because some N2 may be formed in the process and if the bottle is tightly capped, this may lead to pressure
buildup.
aromaticfanatic - 4-12-2020 at 22:41
I believe sodium thiosulfate can destroy cyanide. You should already have some if you were playing with cyanide as it is the antidote.
Just don't add any acids and make sure whatever route you go you doesn't create acids in situ. Cyanide + acid is NOT safe/good/smart/healthy in any
way shape or form (unless you have the proper equipment).
The bleach and NaOH method is fine just watch for spillage with the larger amounts of liquid. The nitrogen gas needs to be able to be vented or as
woelen has said, you will build up pressure. Make sure no one can get to that bottle on accident. That includes animals. A loose lid on a caustic and
toxic solution is not something to just leave around unattended. I'd go as far as to set up some glassware that stays in the lab and has a tube to
vent the gases to the outside. Stopper off any other necks of the flask and you prevent knocking over a bottle with caustic and toxic liquid. Add a
clamp and a good stand and you're as safe as it probably gets.
Besides making the solution accidentally acidic I think you have not other issues to deal with besides the obvious toxicity. I would advise taking a
small sample of the liquid you have and testing it for leftover cyanide. Don't quote me on this but I think adding iron sulfate to the solution should
make prussian blue which will indicate cyanide presence in the form of a blue color.
LifeisElemental - 16-12-2020 at 09:50
As an update I did destroy it per Woelen's advice. I did it in a fumehood and all went well. I would recommend stirring the solution if anyone wants
to do this as, after a night sitting out I sealed the container and shook it and much gas was evolved. I shook it vigorously and let it continue to
sit until no more bubbling/foaming occured.
Fluorite - 16-12-2020 at 16:34
You can add ferrous sulfate to convert it to Ferrocyanides