Rod mill, also named ore grinding mill or ore rod mill, is a type industrial grinding mill used for grinding ore or ore materials. Although similar in operation, a rod mill is often more effective than a ball mill as it requires lower rotational speeds and less steel to achieve the same results. It is, however, limited to maximum rod and drum lengths of approximately 20 feet (6 meters) and is generally only used for wet grinding processes. The rod mill also tends to suffer from accelerated drum liner and lifter wear due to the increased weight of the rods.
Rod mills operate at lower speed than ball mills since the rods are rolled and not cascaded. For an equivalent grind, a rod mill uses less steel than a ball mill because of the lower speed and better contact between the media and ore. The rod charge must be maintained in good working condition, and broken and worn rods must be removed. Rod mills usually require greater operator attention. It is important that the rods stay essentially parallel to one another.
The operation speed of rod mills is generally determined by the peripheral speed of the Inside of the mill. Generally, rod mills operate between 280 feet per minute and 480 feet per minute at the periphery of the mill.