Ball mill and Rod mill is widely-used grinding equipment. They have similarities in shape and grinding principles,there are also differences in structure, performance, and application. This article analyzes their similarities and differences in several aspects and tells customers how to choose a ball mill and a rod mill. From the analysis of the crushing mechanism, whether ball mill or rod mill, when the cylinder rotates, the grinding medium (ball or rod) in the cylinder is lifted to a certain height with the rotation of the cylinder under the action of friction and centrifugal force. Then it is thrown at a certain linear velocity, so that the material in the cylinder is impacted, ground and extruded to be pulverized.

1, Different structure 

Their barrel shape ratio is different. The length and diameter ratio of rod mill is generally 1.5-2.0, and the inner surface of the liner on the end cover is a vertical plane. The length and diameter ratio of ball mill is small, and in most cases the ratio is only slightly greater than 1.

In addition, the rod mill barrel speed is lower than the ball mill’s, so that the medium inside is in a sloping state.

2, Different discharging ways

 In the ball mill, there are commonly used grid type ball mills and overflow type ball mills (named from different mine discharge structure), while rod mills do not use grid plate for mineral discharge,there are only overflow type and open type, and the hollow shaft diameter is generally larger than that of a ball mill of the same specification.

 3, Different grinding media

Rod grinding mills usually use steel rods with a diameter of 50-100mm as the grinding medium, while ball mills use steel balls as the grinding medium. The difference in the grinding body is the main difference.

 4, Different performance

The finished product of rod mill process is rough, but the particle size is uniform, containing less coarse particles and slime, over-grinding is lighter. The ball mill are high production capacity, strong adaptability to materials, high fineness of materials, fine finished product size, easy to grind finely, and energy saving, but the over-grinding phenomenon is serious.

5, Different usage

When gravity beneficiation or magnetic beneficiation for tungsten ore and other rare metal ore, rod mill is often used to prevent over-grinding; in the second-stage grinding process, rod mill is generally used as the first stage grinding equipment,which has a large production capacity and high efficiency. When dealing with soft or less hard ore, rod mill can be used instead of short-head cone crusher for fine crushing, which is not only simple in configuration, but also lower in cost, and can simplify dust removal in the work shop. However ball mill machine is prone to over-grinding due to the fine grinding material, and is not suitable for gravity benefication line.