My understanding is that these multi-step processes are around...

My understanding is that these multi-step processes are around ways of removing various impurities. If natural graphite has a low to extremely low concentration of a problematic impurity, no process steps would be needed to remove that metal or group of metals or existing steps would take enough away to get to required grades.

I suspect its very likely that the residual metal concentrations in black mass are an extremely different mix than the residual metals within natural graphite. If correct, while a natural graphite purification processes work on black mass, they are unlikely to be an optimised process for black mass. For example the residual concentrations of Copper, Lithium, Manganese, Nickel and Cobalt are likely to be much higher in post recycling Black Mass than in natural graphite. While recycling processes do recover most of these metals they don't recover them all meaning they still need above-average removal from the black mass to get back to 99.95% purity graphite.

I therefore expect the different patent/steps is around optimising the process for the differences between dealing with natural and black mass starting material. Different processes depending on how "dirty" the starting product is.