0.074mm finished product by MQY-2740 energy-saving overflow ball mill supplier for grinding with ISO of China manufacture

What Are These Machines and How Do They Work?

A Ball 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.

Ball Mills 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 recalculated 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.

This formula calculates the critical speed of any ball mill. Most ball mills operate most efficiently between 65% and 75% of their critical speed.

Application:

Ball mill is the key equipment for grinding after the crush process, and it is widely used in the manufacture industries, such as cement, silicate, new building material, refractory material, fertilizer, ferrous metal, nonferrous metal and glass ceramics.

It also can be used for the dry and wet grinding for all kinds of ores and other grind-able materials.

Types:

Mill could be sorted as following:

As per the grinding media: ball mill, rod mill and AG Mill (without grinding media).

As per material discharging mode: wet grid mill, dry grid mill & overflow mill.

As per driving mode: side & central driving. The former is more popular now.

As per driving configuration:

a. Asynchronous motor driving: Asynchronous motor + Reducer + Pinion +Girth gear

b. Synchronous motor driving: Synchronous motor+ Air clutch+ Pinion +Girth gear

c. Asynchronous motor + reducer + diaphragm coupling

Structure of Ball mill: 

The machine is composed of feeding part, discharging part, turning 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 turning gearwheel adopts casting hobbing process and the drum is equipped with wear-resistant liner, which has good wear-resistance. 

Technical Parameters