There are a few problems that I beleive pose metallurgy problems and make this a unique deposit even among Vein deposits.
#1 the host rock is quite porous resulting in the graphitic overprint. Yes there is veining but one could not characterize it as similar to that in Sri Lanka. Typcial veins deposit mineralization runs in veins one to 3 meters maybe a bit more. Because the host rock is porous and the zone quite large it the graphite is distributed over a larger area. Thus resulting in a lower grade and impurities hat are a little more difficult to clean out.
The difference in geological setting between Albany and the Sri Lankan deposits could end up being this deposits fatal flaw. Because the Key characteristic that the Sri ankan deposits have this one is missing. SImply the graphite is being deposited in a much smaller area vs Albany's granite geoligical setting. In Madasgar the deposits there are formed be mtamorphic action in the earth which allows the mineral to be deposit and most of the deposits there are nearly vertical. The same action may be true for Albany making it slighlty different than your typical Sri Lankan Vein Deposit.
Like I said before. There are better deposits in the USA that are more typical of what a vein graphite deposit would be and are much higher grade and I am suggesting would be much easier to purify than Zen.
And again... purity is only one key to spherical graphite... the other is large flake which allows for a lot less product loss than using medium or fines.