The Cerenergy solid state electrolyte tube is mainly made from...

The Cerenergy solid state electrolyte tube is mainly made from HPA but it's not 4N. 3N (99.9%) is fine.
I asked Iggy about this a couple of years ago.
From the DFS:

It doesn't go into detail but I assume the 3N HPA is one of the four 'key' items.

The process of making Silumina actually creates the 4N HPA used to coat the Silicon particles.
Boehmite is the main raw material - and it's cheap and available compared to the eye watering cost of Silicon.
From the DFS:


'As far as I know, they have taken their knowledge on HPA to an application of HPA where there is potentially greater value'.
I agree.

The company sunk ~ AUD40m into the HPA plant in Johor. No point selling it at this stage as they would receive very little.
If Silumina is ever successful (and I'm having my doubts given the pilot plant black hole), then it could also be produced in Johor utilising the investment already sunk.
The Capex required is far less than the HPA plant, and on paper far more profitable.
They would need to source the Silicon locally or elsewhere in Asia.
Just IMO, but I think the prince would like that outcome very much.