When does Potassium Ferricyanide release Cyanide gas?

[Fulvio]

I have been making cyanotypes since 2-3 years or so. I'm quite happy with them and has been the most reliable alternative process I know.

I've heard about Mike Ware alternative new formula, which adopts Ferric Ammonium Oxalate III instead of Ferric Ammonium Citrate III.

I don't have any Ferric Ammonium Oxalate III so I'm not going to experiment.

But I was wondering, what would be the reaction of mixing Ferric Ammonium Oxalate and Potassium Ferricyanide?

Does the reaction between Potassium Ferricyanide and an oxalate produce some heat? Isn't there any risk that Cyanide gas would be released?

Besides the new cyanotype thing, what are the actual risks of poisoning oneself with potassium ferricyanide?

 

[Photo Engineer]

Ferricyanide does not release any cyanide under most lab conditions unless you add very very strong acid and heat the solution.

There are others that can give you exact details, I'm sure.

PE

 

[Ian Grant]

If you mix it witch oncentrated Sulphuric acid you'll get hydrocyanic gas which is

I used to work with cyanide solutions alot, and had to acidify them prior to gold/silver recovery. Now that is dangerous.

However ferricyanide is relatively harmless in comparison, just keep it away from strong or hot acids. Ferricyanide will make you physically sick if you ingest it, risks are therefore minor.

Simple precautions like keeping work areas clean and hands well washed are sufficient.

Ian