Yes milling release the impurities but its the flotation step the seperates the impurities from the concentrate and thus improves the concentration. As an anology you have a bowl of wall nuts. You crush the wallnuts so u now have a mixture of shell (impurities) and the nut (graphite) you still need to remove the shell from the nut (flotation) to increase the concentration of wallnuts in the ball.
In flotation, physical seperation is based on the difference in the ability of air bubbles to selectively adehere to the graphite surface in a graphite/water slurry. The graphite particles with attached air bubbles (hydrophobic particles) are carried to the surface, while the particles that are completely wetted (hydrophilic) stay in the liquid phase. Partical/bubble collision is affect by the relative size of the partical. If the bubble is too large relative to the particle then the fluid flowing around the bubble can sweep the particle past without coming into contact. Hence my previous comment about recovery and particle size.
As your per you comment about the board appointment, the same can be said about SYR's recent appointment. In fact i think that appointment could be a game changer as securing offtakes in the li ion space is the biggest risk for both companies. I have been putting off buying syr until i see the outcome of the spherical graphite study although with the new appointment that maybe too late
