| Description |
The problems of corrosion and abrasion of media and liner in a wet grinding mill have been reviewed. The Kalman filter has been suggested as a method for estimating the ball and liner wear within a mill. The principles behind the Kalman filer have been explained, and then the has been implemented with simulated mill data to estimate the rock holdup, the water holdup, the ball holdup, the liner weight, the ball wear rate constant, and the liner wear rate constant within the mill as a function of time. Measurements of power and bearing pressure were used to make the estimates. The filter made fairly accurate estimates of the ball holdup, and even better estimates of the water holdup. The ball holdup and liner weight estimates, however, were off by about 10 tons each; the ball holdup was estimated high and the liner weight was low. This suggested that the filter was unable to distinguish between ball and liner weights. One modification was made in the power model equation to include diameter in hopes that it would help distinguish liner weight (which depends on mill diameter) from ball hold up. The improvement was minimal. Therefore, further suggestions were made for improvement of estimates which can be made in the future. Once good estimates are made, the relative importance of abrasion and corrosion can be made. |
