A laboratory study of the performance characteristics of mill pulp lifters

Although pulp lifters are an integral part of the majority of grate discharge grinding mills, the potential problems imposed due to their improper design have only come to light in recent years. Ideally, at a particular mill hold-up, the discharge rate through a grate-only assembly should be matched by the capacity of the pulp lifters. Recent industrial experience has suggested that this is not always the case and can lead to a dramatic reduction in mill capacity. A research program was therefore initiated at the JKMRC to study this aspect of mill operation. aper presents the results obtained to date from experiments carried out in a laboratory SAG mill with grate-only as well as grate and pulp lifter arrangements. Scale models of industrial pulp lifter designs were used The results illustrate the influence of pulp lifter chamber volume and show that over a wide range of values, the discharge capacity of the pulp lifter assembly was always less than that of a grate-only configuration. The cause of this problem is explained together with comparisions of different pulp lifter designs.