Doggo, No, The purity or inpurities come later when it goes for lab analysis. It can be done same day but it would be prudent to produce a few tons before sampling for purity and quality. There is quite a bit of work to do after announcing that production has started(in fact they can announce production when they fill their first bag of MgO). As I have said before, one of the most critical performance metrics is the extraction efficiency - how much fly ash for a ton of Mg. That is a critcal element that underpins performance of thge hydromet process and cost of production which leads to profitability - that may take a month or two after they fine tune the operating process.
