Generally, when the ball is initially loaded, the steel ball ratio of cement raw material milling shall be determined according to the value given by the manufacturer.After the lining of cement raw material milling is worn to a certain extent, the content product of cement raw material milling will increase due to the decrease of lining plate thickness, which will reduce the output, resulting in the discharge and stone discharge of cement raw material milling.In order to maintain a reasonable filling rate and ensure the output of cement raw material milling, it is necessary to increase the steel ball quantity of cement raw material milling, generally 5% ~ 15%.In addition, when replacing the lining plate in the later stage, the steel balls shall be screened, and the broken steel balls and small-diameter steel balls shall be cleaned in time.