In an open circuit system, the feed rate of incoming clinker is adjusted to achieve the desired fineness of the product. In a closed circuit system, coarse particles are separated from the finer product and returned for further grinding. Gypsum is interground with the clinker in order to control the setting properties of the cement.
Open and closed circuit dry grinding of cement mill rejects in a pilot scale vertical stirred mill. ... In this study, separator rejects of a closed circuit cement tube milling were dry ground in a 10-l pilot scale vertical stirred mill. Tests were done as open and closed circuit.