The grinding mill is a type of machine that is used to shred large pieces or coarse materials into fine fragments. There are numerous grades of output that can be achieved depending on the specific type of grinder used. Some grinders have high power capabilities and can be used to grind pieces as large as 0.5 inches in diameter. Others are only specialized for grinding small sized material into extremely fine fragments. The crushing may be done dry or wet depending on the type of grinder used. There are four major types of crushers used for grinding. These are the ball mill, sand mill, attrition mill, and small-media mill.
The ball grinding mill is specially meant for coarse materials. It works by the principle of friction and abrasion. The coarse fragments are fed into a spherical rotating ball which makes them collide against each other. Friction and abrasion processes are responsible for grinding in this type of crusher. The ball mill is generally known for its effectiveness in crashing large sized material into very fine particles with a grain-size diameter of about ten microns. Attrition mills are appropriate for medium sized pebbles with a diameter of less than 10mm. They give a fine output with fragments as small as 1 micron in diameter.
The small media grinding mill (also known as the sand mill) is specially meant for small pieces as defined by the name. It can only work with materials with a grain size of less than 1/8 inches. Most industries in the recent past have employed this type of grinder due to its effectiveness in ultrafine grinding. There are numerous factors that affect the choice of mill used for grinding. However, the most outstanding factor is the grain size of material to be ground. Other factors include power consumption, effectiveness, speed, and economic viability of the machine.