I have located a source of Ammonium Ferric EDTA powder here: http://www.newalliance.biz/prange.swf
It is made to customer order/specification, and the data sheet says it is 85% pure (max?).
So, this may change the landscape a bit regarding powder blixes. I have to do some calulations. It may turn out to be uneconomical or it may turn out that due to purity there is an issue. This does not change the picture regarding blixing of films, just the potential activity of powdered blixes and bleaches that use Ammonium Ferric EDTA.
I did this while Ian was sleeping in Turkey.