Working principle of ball mill

Grinding ore is typically carried out in a grinding mill. There are many types of grinding mills, but ball mills and rod mills are commonly used in metal mines. Pellet mills and autogenous mills have seen increasing application in China in recent years. A ball mill or rod mill is a rotating cylinder with hollow shafts at both ends, containing a considerable number of steel rods and balls.

Ore and water are fed into the cylinder from one hollow shaft and discharged from the other. As the ball mill cylinder rotates at a specified speed, the steel balls and rods, along with the ore, rise to a certain height under the influence of centrifugal force and friction, then detach from the cylinder wall and fall or slide down. They then rise to the same height again and fall, repeating this cycle periodically, subjecting the ore to impact and abrasive action, thus grinding it. The ground ore and water form a slurry (wet grinding), which is discharged from the hollow shaft at the discharge end, completing the grinding process.