Titanium Dust is a source for Titanium Ingot, needed for many of the endgame machines.
The source of the first few Titanium Dust will be crafting from Small Pile Of Titanium Dust
Later, Titanium Dust is best aquired by crafting from Uu Matter
Crafting Table recipe:
Grinder recipe: Titanium Ingot → Titanium Dust
Blast Furnace recipe: Titanium Dust → Titanium Ingot