Uranium Dust is a transitory state of Uranium, allowing you to produce fuel for your Nuclear Reactor more effectively. It can also be used to make 1.000.000 amplifier units in a Mass Fabricator or Matter Fabricator
Uranium Dust is mainly acquired by Macerating, Pulverizing or Crushing Uranium Ore. The most effective way is to mine the Uranium Ore (Block) with Silk Touch (using e.g. Rock Cutter), then process it in an Industrial Grinder.
Uranium Dust can be used to produce radioactive cells and dusts in an Industrial Centrifuge. 4 piles of Uranium Dust create 4 Uranium Cells, 2 Thorium Dusts, a single Tiny Pile of Plutonium Dust and a single Tungsten Dust. This is much more profitable than putting the Uranium Ore in a Compressor for Refined Uranium. Alternatively you can use it as an amplifier (1 million) in the Mass/Matter Fabricator or craft it into Plutonium Dust with a UU-Matter.