ABSTRACT
Grinding is the last stage of the comminution process. The particles are reduced from a maximum upper feed size of 3/8 inch, to some upper limiting product size ranging between 35 mesh and 200 mesh. A rod mill uses rods as a grinding medium. Length to diameter ratio is between 1.5 and 2.5. A tube mill is a grinding mill where length to diameter ratio is 3 to 5. It is also known as a pebble mill as it uses ceramic pebbles made of flint or porcelain as the grinding media. Mesh of grind is the term used to designate the size of the grounded product in terms of the percentage of the material passing through a given mesh. Special feature of closed circuit grinding is the removal of the product from the grinding mill as soon as the material is grounded to the required size so that overgrinding is avoided.
