[...] what other parts the centrifuge has which need to be designed [...]
Quite a few! This depends very much on the density difference and grain size of the solid. What azimuthal velocity did you determine? At 100m/s everything is easy, at 300m/s it's difficult, at 400m/s extremely difficult.
The bearings must be chosen, with possible imbalance in mind, and if no ball or hydrodynamic bearings fit the task, you may need aerodynamic or magnetic bearings, whose market availability is limited and may demand a special design. That alone would be a heavy task with unexpected worries.
In case you need to rotate in vacuum because of aerodynamic losses, you must acquire, let design or design yourself a vacuum chamber.
Depending on the engine you need, it may not be available commercially, or need a tailor design by a manufacturer, or you have to design it. Same story for its drive electronics.
Expect questions and possible difficulties with governmental agencies, depending on the materials needed, especially for centrifuges. Maraging steel and some aluminium alloy tubes cross borders with difficulties because of uranium enrichment, but the much more efficient graphite fibres aren't controlled.