ANS:C - fine grinding

A ball mill is primarily used for fine grinding.

Explanation:

• Ball Mill: A ball mill is a cylindrical device used in grinding (or mixing) materials like ores, chemicals, ceramic raw materials, and paints. It operates by rotating a cylinder with steel grinding balls, causing the balls to fall back into the cylinder and onto the material to be ground.
• Purpose:
  • Crushing: Ball mills are not typically used for primary crushing but rather for refining crushed materials.
  • Coarse Grinding: Although ball mills can handle larger feed sizes, their primary function is not coarse grinding but rather fine grinding.
  • Fine Grinding: Ball mills are widely used for fine grinding of materials. They are efficient in grinding down to very small particle sizes, typically in the micron or sub-micron range.
  • Attrition: While some attrition may occur due to the tumbling action of the grinding media (balls) inside the mill, ball mills are not specifically designed for attrition.
• Applications:
  • Ball mills are commonly used in mineral processing, cement, ceramics, and chemical industries for fine grinding applications where particle size reduction and homogenization of materials are required.