The main forms of ineffective grinding ball are wear, crushing and out-of-round. Crushing and out-of-round will lower the grinding efficiency and accelerate the abrasion of the grinding balls at the same time. Generally speaking, abrasion of the main reason causing ineffective grinding ball. Under the effect of materials and lining board and the mutual squeezing of the grinding balls, the wear mechanism of grinding balls of ore milling equipment includes the following four types:
1. Cutting and chisel-cutting wear
The applied force on the surface of grinding balls can be divided into normal applied force and tangential applied force. Under the effect of normal force, the sharp materials such as abrasive materials that move in the opposite direction with grinding balls will embed on the surface and the tangential force will push abrasive materials to move along the surface of grinding balls. Abrasive materials with low hardness will produce shallow scratch on the surface and materials with high hardness will cause cutting furrow.
2. Brittle chipping
According to the different tenacity of materials, the surface of grinding balls of ball grinder will have chipping after many times of impacting, which will cause abrasion. In the ferrochrome grinding balls, carbide is hard and crisp. When the soft tissue around it is abraded and its containment effect is lost, isolated carbide will be cut and broken by the abrasive materials that repeatedly slide.
3. Corrosive wear
In the wet type rod mill, the corrosive media and grinding media work on the surface of materials at the same time, thus corrosive wear will be caused, which will damage the mechanical property of the surface of materials, thus intensifying the abrasion.
4. Fatigue wear
Under the repeated impact stress, contact pressure stress and shearing stress, grinding balls will be repeatedly hit, squeezed and slid, the brittle phase, occluded foreign substance or hole on the subsurface stratum will have fatigue cracks which will grow and interweave, and finally cause chipping and wear on the surface of grinding balls.