Direct impact characteristics of magnesite fragmentation by pulsed discharge in water

To clarify direct impact characteristics (pressure and position) of middle-grade magnesite fragmentation by pulsed discharge in water, this work uses pressure film to accomplish passive measurement through pulsed discharge experiment and obtain the pressure. The impact position is determined by image analysis of fragmentation product morphology, crack edge and discharge channel. Then, pressure load on magnesite surface is numerically analyzed based on the measured pressure obtained from the film. Results indicate that, at 10 mm discharge gap, the impact pressure increases with the discharge voltage, and the discharge voltage to disintegrate magnesite is −40 kV. The impact position is normally in the boundary among different mineral components. Simulation analysis indicates that, the pressure load applied directly on magnesite surface is approximately 142.5 MPa at −40 kV and greater than the compressive strength of magnesite, thus leading to the fragmentation.