Effect of mill speed and slurry filling on the charge dynamics by an instrumented ball

Abstract

In the ball mill, the motion of charge is a complex system, especially under wet grinding. It is difficult to measure the charge physical quantities and hard to validate the correctness of charge motion simulation. To this end, an instrumented ball which is capable of measuring the charge physical quantities was designed. The laboratory ball mill was lined with 12 pieces of trapezium lifters and filled with Jb = 25% grinding balls. An iron ore was used to prepare the slurry at 50% solid concentration by mass. A series of tests were carried out to investigate the charge dynamics at different mill speeds and slurry filling. The average rotational kinetic energy, average applied force and mill power were measured and analyzed. The results showed that the average rotational kinetic energy increases with mill speed, whereas the average applied force first increases and then decreases. The average rotational kinetic energy and applied force first increases and then decreases by the increase in slurry filling. Furthermore, there exists a slurry filling U = U* that the mill power has a maximum value.