Tubular Ball Mill and rod mill
As crushing only does not generally liberate a mineral processing plant , further size reduction is usually required. This is achieved by grinding the crushed ore in tubular mills or devices like pan mills or roller-grinder mills. Intubular mills, a grinding media such as steel balls, rods or hard pebbles, impart the forcesrequired for size reduction. On rotating a mill charged with rocks and grinding media, theentire charge rises against the perimeter of the mill in the direction of motion. On reaching acertain height, part of the charge cascades and falls to the bottom of the mill, the other parttends to slips down but soon travels in the direction of motion of the mill. During this process,the media drops repeatedly on to the rock breaking down its size. Some size reduction also takes place due to abrasive forces. As a result of the combined action of repeated impact and abrasion over time, size reduction takes place and given sufficient time the mineral of interest is liberated. ...