[milapgoud]

Can a mixture of Calcium carbonate and calcium oxide be grinded to size < 0.1 micron to convert the compound to nano-particulates? If yes,  pl. suggest method for lab as well as commercial scale implementation.

[Enthalpy]

I see no mechanical difficulty in grinding weak brittle solids to <100nm. That's not even very fine: graphite and MoS₂ powders are generally finer, like 20nm. But they tend to build bigger clumps.

The real difficulty to my eyes is that CaO is very reactive to moisture and carbon dioxide, and powders make it worse.

https://en.wikipedia.org/wiki/Lime_(material)
they don't tell the grain size.

[jeffmoonchop]

One method would be ball milling. Its just an instrument with metal chambers in which you weigh your sample. You add one or more ball bearings and the instrument just shakes it at a set rate. The amount of time you mill it should decrease the particle size. It can put a lot of energy into the sample though so regular rests will be needed to let it cool down.