Clay Dust produces useful resources in the Industrial Electrolizer (notably Silicon, which you can never have enough of).
You can get Clay Dust from opening Scrap Boxes or by grinding Clay Balls.
You can also get Clay blocks from UU-Matter, but the only way to turn it into Clay Balls is to manually place it down and mine it.

It would be nice to be able to automate that process, e.g. the Grinder could grind Clay blocks into 4 Clay Balls, which can then be ground again into Dust.
Conversely, though not necessary, the Compressor could compress 4 Clay Balls (and Dust?) back into 1 Clay block.
The latter is doable through the Auto Crafting Table, but that is currently bugged (#2332) and is also slow and not upgradeable.