#### An experimental study on the ultrafine grinding of gypsum ore .

WEBThe P80 of μm was achieved at a mill speed of 53 rpm and grinding time of 13 min with the interactional effects of mill speed and grinding time. Öksüzoğlu and Uçurum [27] studied the ultrafine grinding of gypsum ore in a dry ball mill. In their grinding tests, the mill speed was varied from 50 to 90% of the critical speed for gypsum ...