Industrial ball mill: definition and principle of operation
Ball mills are a type of rotary mill. They consist of a cylindrical or conical housing made of steel and internally lined with a ceramic, high-carbon steel or rubber cover. The housing is mounted on a metal frame and rotates on its longitudinal axis. It has a series of balls inside, of different diameters, which can occupy between 30 to 50% of the internal volume; they are responsible for generating the grinding. They can be used for wet or dry materials.
Different functions are possible based on the dimensions of the balls: large ones can break the coarser feed material, so that the smaller ones perform the fine grinding, adjusting the particle size. The grinding media material can be varied so that the balls are tougher and abrasion-resistant. Typically, alumina, zirconia, silica, or other media appropriate to the material to be ground are used.
Particle size reduction in the industrial ball mill is gained with the impact force and frictional wear that occurs as the balls rotate with the rotation of the housing and fall on their way to the base.
Ball mill operating parameters
The degree of grinding in ball mills is determined by the following factors:
Time the material stays inside the grinding chamber.
Diameter, density, and number of balls.
Hardness of the ball material.
Grinding chamber load level.
Cylinder rotation speed.
In the industrial ball mill, the critical speed principle applies. At this point, the spheres, which determine the degree of grinding, start to rotate in unison with the housing, without impacting the material to be ground. This is one of the factors that motivates the study of materials in the laboratory ball mill, in order to determine the parameters that govern the process prior to industrial scale-up.
At Foeth you will find a wide variety of ball mills used for many applications in industrial processes. Call us or write us via our contact form for information. Select ball mills for your processes at Foeth!