Is 22 the new 15.5, page-70

Freehold,

ontop of the 'costly and high temp' thoughts, not exactly true, just a few points to consider:

1. They only dried at 400'C to get that purity. If they were building a plant, likely they could do it at lower temps depending on throughput.. unless they have some problematic organics that need to be ignited at 400'C.. but I doubt it. LOI is normally done at those temperatures for other materials so it was probably just the standardised test used at that laboratory.

2. HF is very nasty stuff, humans get side effects just being around the vapour (including bone density loss).. will be very hard to get permits to use on large scale..