I don't follow BKT that much but the last report I read said...

I don't follow BKT that much but the last report I read said they "evaluated" both methods and announced thermal purification achieved a higher purity than acid. I don't recall them saying they have abandoned "non-acid". But whatever they do is up to them. Most graphite companies are going the "greener" path, for obvious reasons, i.e. their product will be used in what the general buying public perceives as being a "greener" less polluting mode of transport that what is currently available.