Rod Mill grinds material by rotating a cylinder with steel grinding balls, causing the balls to fall back into the cylinder and onto the material to be ground. The rotation is usually between 4 to 20 revolutions per minute, depending upon the diameter of the mill. The larger the diameter, the slower the rotation. If the peripheral speed of the mill is too great, it begins to act like a centrifuge and the balls do not fall back, but stay on the perimeter of the mill. The point where the mill becomes a centrifuge is called the "Critical Speed", and ball mills usually operate at 65% to 75% of the critical speed

Rod Mill Application:

are generally used to grind material 1/4 inch and finer, down to the particle size of 20 to 75 microns. To achieve a reasonable efficiency with ball mills, they must be operated in a closed system, with oversize material continuously being recirculated back into the mill to be reduced. Various classifiers, such as screens, spiral classifiers, cyclones and air classifiers are used for classifying the discharge from ball mills. Ball mill is an efficient tool for grinding many materials into fine powder. The ball mill is used to grind many kinds of mine and other materials, or to select the mine. It is widely used in building material, chemical industry, etc. There are two ways of grinding: the dry process and the wet process. It can be divided into tabular type and flowing type according to different forms of discharging material.

Working principle:
The Rod mill is horizontal cylindrical rotation device, driven by brim gearwheel. There are two chambers and grid. Material goes into the first chamber through the feeding inlet. Inside the first chamber, there are stage liners and ripple liners as well as steel balls. The shell rotates so as to generate electricity, and this force brings ball to a certain height and then balls drop down by gravity, the impact is the grinding force to the material. After the primary grinding, materials go into the second chamber through segregate screen. In the second chamber, there are flat liners and steel ball, after the secondary grinding, material is discharged from the discharging. Then the whole grinding process end.
Structure:
The Rod mill is composed by feeding part, discharging part, rotation part and driving part (reducer, small driving gear, electric motor and electric control). The quill shaft adopts cast steel part and the liner is detachable. The rotation big gearwheel is made by cast hobbling processing and the drum is equipped with wear-resistant liner, which has good wear-resistance. The machine is with stable and reliable working condition.
Main technical parameters of rod mill：