Measurement of the radial and tangential forces exerted by the load on a liner in a ball mill, as a function of load volume and mill speed

Abstract A laboratory grinding mill of diameter 0.36 m was modified to allow the measurement of the radial and tangential forces exerted by the load in the mill on lifter bars of varying profiles. Four load beams were used to achieve these measurements. Electrical conductivity measurements were used to determine when the load was “locked in” to the liners. The mill was instrumented to allow accurate measurement of the torque drawn by the mill. The above measurements were obtained for mill speeds varying between 10% and 135% of critical speed, load volume varying between 0% and 37% of mill volume, for seven different liner profiles. Steel balls of diameter 3, 4 and 5 mm were used as media (equal proportions of each); no ore was used. The measurements provide detailed and quantitative information about the forces exerted on the liner and about the behaviour of the load in the mill. Analysis of these data should provide insights relevent to the optimisation of mill performance with reference to liner and media wear and power consumption, i.e. the major factors determining operating costs in rotary mills.