New insights on the breakage mechanism of magnetite quartzite via high voltage pulse discharge: liberation, property difference, micro morphology, and numerical simulation

Abstract

Herein, new insights on the breakage mechanism of magnetite quartzite via high voltage pulse discharge were proposed. The liberation of magnetite quartzite was significantly enhanced by high voltage pulse discharge. The ground products liberations of pulse numbers 300 were improved by 20.93% at grinding time 3 min. The iron distribution rate of high voltage pulse breakage in −0.074 mm were improved by 29.04 percentage points at pulse numbers 300. The linear thermal expansion coefficient of magnetite and quartz were 7.52 × 10−6 °C and 5.70 × 10−7 °C, thus different expansion deformation and thermal stress of grain boundary expansion generated to promote the grain boundary separation of quartz and magnetite. The impact wave force destroyed the intergranular force rather than the intragranular force preferentially during the high voltage pulse breakage. A distorted electric field was generated at the mineral interface to produce grain boundary cracks and realized the macro fracture of magnetite quartzite.