Batch grinding kinetics in the presence of a dead space, as in a hammer mill

Abstract It is shown that the presence of a dead space in a hammer mill leads to apparent non-first-order breakage of the top feed size in batch grinding. The equations to describe the disappearance of the top size are obtained, as are those for the total size distribution as a function of time. Examples are given of the effects caused by the magnitude of the dead space and the rate of mass transfer between the active and inactive space. The concepts may be applicable to other mills where dead space can exist.