Crushing as well as grinding are aimed at size reduction. But there are certain differences in these operations which are cited below.
1. The solid particles are reduced in size by compression.
1. The solid particles are reduced in size by impact and attrition.
2. It is aimed at breaking large pieces of solid material into small lumps.
2. It is aimed at reducing crushed feed to powders.
3. Mostly crushing equipments are operated in open-circuit.
3. Grinding equipments are always operated in closed-circuit.
4. When crushers are operated in closed-circuit, dry screens are used as a size separation unit.
4. In grinders operated in closed-circuit, some sort of classifier is used as a size separation unit.
5. This operation is performed on dry feed material.
5. This operation can be performed on dry as well as wet feed.
6. In crushing operation, the reduction ratio seldom exceeds 6 to 8.
6. In grinding operation, the reduction ratio as high as 100 is possible.
7. Crushing is usually one shift operation as residence time in the crusher is less and throughput is large.
7. Grinding is carried out in all shifts as in the grinding machines the residence time is larger and throughput is smaller.
8. Crushers are of two types, e.g., primary crushers and secondary crushers.
8. Grinders are of two types, e.g., fine grinders and ultrafine grinders.
9. Crushers are heavy duty, low speed machines.
9. Grinders are relatively light duty, high speed machines.
10. In coarse crushing, the feed size is 1500 to 40 mm and product size is 50 to 5 mm.
10. In fine grinding, the size of feed is 5 to 2 mm and product size is 0.1 mm (about 200 mesh).
11. Energy consumption per unit mass of product is low due to coarse particle production.
11. Energy consumption per unit mass of product is high due to fine particle production.