How can I get the silver out of used E-6 blix? With b+w fix I use electrolysis, but I heared, this is not possible with blix. Can I use Sodium dithionite?
You can use electrolysis but at a much lower ampage. The easiest method is to pass through wire wool cartridges, depending on the volume you can make something up yourself.
Well, here is another reason why a bleach then fix is used with films. Silver recovery from blix is much less efficient and takes longer than from a fix. With the high silver load of film, the use of a bleach then fix, the silver recovery in large scale is easier.