Here go some comments from a mechanical engineer, so, I'm more centered in the process itself, not in the chemical part...

Hard to tell. Your question is the same as asking "how much time it will take to decantate the solution"? Depends on the solution. Maybe someone here can help with some tip, but my suggestion would be: borrow one small centrifugue from a friend, and make some experiments. Determine it empirically, may be easier.

The power requirement? Depends on the size of the equipment, its arrangement, and how you're going to do that. Are you sure you cannot do it continuously, I mean, through a vortex generator in the line or so, instead of batching it in a conteiner? Just a thought.

Depends on the particle size, the difference in density between the solid and the liquid, the viscosity of the liquid and the radius of the centrifuge.

Is there scope to do a range of pilot plant tests, perhaps, and then scale-up?

Alpha-Laval and Westphallia make top centrifugues. A 15 kw motor and 6000 rpm machine will pump about 6 m3/h of feed liquid.

specific weight of solid? lighter than solution ? heavier? The diffrence makes the diffrence