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Ferroxyl alternative

 

Dear Sirs,

We are asked by our client to use "Ferroxyl" as a test medium to detect iron contamination on titanium surfaces of the pressure vessels we are to build. As Ferroxyl is a very toxic substance, we are looking for an alternative agent to do the same task. Unfortunately copper sulphate ⇦this on eBay or Amazon [affil links] has been ruled out by the client as being too insensitive for this purpose. Could you please advice for an equally effective testing agent however much less dangerous?

Sincerely yours,

Wolfgang Graaf
- Coffs Harbour, NSW, Australia

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There is nothing particularly toxic about the ferroxyl test solution. It contains potassium_ferricyanide, which should not be confused with a simply cyanide salt. The ferricyanide radical is a very stable complex and it is NOT possible to make it generate hydrogen cyanide gas. It is such an innocuous substance that it doesn't have a UN number or a Hazchem number or a Dangerous Goods number, etc.

Bill Reynolds [deceased]
consultant metallurgist - Ballarat, Victoria, Australia
We sadly relate the news that Bill passed away on Jan. 29, 2010.

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Just to follow up on Bill's comments. Get a pack of table salt and see what the anti-caking agent is. If you do this in the UK you find the ferri-cyanide. I have been putting this on my chips for years without ill effect. Martin Trigg-Hogarth surface treatment shop - Stroud, Glos, England We don't use it in our free flowing salt, and the MSDS does say that it will decompose to release cyanide, although it is a very stable molecule. It is safe in use in the laboratory, I believe that it will show up in cyanide destruction analysis for wastewater, and becomes a problem because it is so difficult to break down. I recommend to clients that it is for this reason, we recommend a PVC lined tank to hold cyanide solutions: so you don't slowly form ferricyanide and have the cyanide analysis problem when qualifying your wastewater for cyanide limits.    Tom Pullizzi Falls Township, Pennsylvania