Course Details
Ball mills accept feed that ranges in size from 80% passing 70mm (ROM Ball Mills) through 15 mm (post a tertiary crusher circuit) to fine feeds of less than 1mm in regrind operations. Products may be as coarse as 0.5 mm or as fine as 40 microns and below. In a ball mill the length may be less than, equal to, or greater than its diameter. A short length mill has a lower retention time and produces a coarser product. Longer mills have a longer retention time and therefore produce a finer grind.