Rust Electrolysis and Stainless Anodes
bill tindall
>There was a post a while back linking to web sites warning about the use of stainless steel anodes. The information had the look of 'Alarmist Science" so I decided to investigate.
The warning was that the chromium containing stainless steel anode would dissolve and make toxic and illegal chromium. I think the concern is as follows. Chromium can exist in three common states-metal, chromic compounds and chromate. The chromate state has been shown to be carcinogenic as well as toxic and disposal of chromate is regulated. This is the compound some of you use to color wood and it was used for many years as an anti corrosion compound (chromate paints, etc). I think it was assumed that if stainless steel dissolved it would make chromate, which I thought highly unlikely for a variety of reasons.
A friend has a 50 gallon electrolysis bath with a high surface area stainless steel screen for an anode. He has run it for days doing things like saw tables, etc. If chromate could be formed, this operation should make it . I took a sample and had my friend Ralph test it for chromium. There was something less than 0.005 oz of dissolved chromium in the 400 pounds of water in the container, and it is most likely that any dissolved chromium is the more benign chromic, not chomate.
So now you have some data upon which to make a decision. If you think that the amount of chromium you may add to the world is significant compared to the chromium dissolving from the megatons of stainless steel in use (which indeed corrodes at some finite rate) then use messy iron anodes.