Properties of Feed Materials Affecting the Sizing Process

PROPERTIES OF FEED MATERIALS AFFECTING THE SIZING PROCESS 

The milling or sizing process is affected by a variety of factors and has a direct effect on the quality of the final product. The properties of feed material and the finished product specifications determine the choice of equipment to be used for the process of comminution. The properties of feed material include melting point, brittleness, 

Materials can be classified as hard, intermediate, soft, or fibrous materials (e.g., glycyrrhiza and rauwolfia) based on Moh s Scale. Fibrous materials require cutting or chopping action and usually cannot be reduced in size effectively by pressure or impact techniques. Before selecting and optimizing a size reduction process one needs to know the properties of the material and the characteristics of a mill. The important material properties (5,10) are as follows  

Toughness The material s resistance to the propagation of cracks. Reduction of the particle size of tough material is difficult, but can sometimes be made easier by cooling the material, thereby diminishing its tendency to exhibit plastic flow, and making it more brittle. 

Brittleness The opposite of toughness. Size reduction poses no problems except if the amount of fines is to be controlled. 

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