I would like to change this title to what is the difference between barite and limestone firstly before answering this question.
This is the basic introduction of baryte and limestone from Wikipedia.
Since they are different in several aspects like their hardness, moisture and etc, the suitable grinding machine for them may have a little difference.
In general, manufacturer who produce barite and limestone grinding mills will give them a same name.
Grinding mills for many ores will be classified into coarse powder mill and ultra fine powder mill. This results from the finished powder fineness.
Now, there are two main different kinds of mineral (powder) grinding mills in the market.
One is the well-known Raymond mill, which produced by our company can grind the ore into powder with 30 to 425 mesh.