The replacement of the Bayer process gets back to the feedstocks...

The replacement of the Bayer process gets back to the feedstocks used too.
A4Ns process probably uses something post the "red mud" stage and so still incurs the carbon footprint of some Bayer.
The output of the Bayer process is Alumina, so there is also another energy intensive step in the Hall-Heroult to get to Aluminium.
The existsing HPA alkoxide cops the energy footprint of both.
I cant see either A4Ns or FYIs (kaolinite or feedstock) replacing Bayer anytime soon, Just look at the production cost comapred to the Aluminium price (which has both Bayer and Hall-Heroult costs in it)