Ann: High Purity Manganese Flowsheet Optimisation Progress Update, page-28

The following is an excerpt from an unnamed broker research paper from this year where they cite 99.7% as being industry standard.
Happy to stand corrected if this is wrong, don't recall ever seeing a number elsewhere but if industry standard is 99.7% , we are already gold.

In CY17 E25 established a metallurgical flowsheet in conjunction with the CSIRO for the purposes of extracting Mn from Butcherbird ores to produce electrolytic manganese metal (EMM) and battery grade manganese sulphate, the latter of which would see E25 leveraged

to the EV thematic as the only downstream processing operation
in Australia. Subsequent bulk test yields have produced electrolytic manganese at a purity well above the industry standard for EMM of 99.7%Mn at 99.95%Mn.