Which devices are used for size reduction of mineral?
In practice, size reduction of mineral particle assemblies is accomplished stepwise in commercial devices. The complicating features in the breakage of large assemblies of particles are the different particle sizes and strengths and the sometimes random way in which stress is applied in the various steps. In mining operations, blasting with explosives is usually the first step in the comminution sequence. During blasting, high-velocity gas pressure pulses created by the explosives load blocks of ores to provide initial fragmentation. The next step in mineral processing plant is typically crushing, which is accomplished by slow compression of large particles (greater than 1 cm) against rigid surfaces. The mechanism of breakage in the crushing step is contrasted with subsequent size reduction by tumbling or stirred mills in which breakage of smaller particles (less than 1 cm) is accomplished by a combination of impact, chipping, and abrasion events caused by energy transferred from gri...