Pre-weakening behavior of magnetite quartzite based on high-voltage pulse discharge

[Display omitted] •The magnetite quartzite was pre-weakened via high-voltage pulse discharge (HVPD).•The positive impact of HVPD was weakened as the grinding time was extended.•The mechanical properties was reduced owing the loose structure and porosity.•The grain-boundary breakage was obtained in the HVPD products. To ascertain the mechanism that the ore grinding characteristics were improved by high-voltage pulse discharge (HVPD) pre-treatment, an innovative experiment system was performed on magnetite quartzite. The HVPD pre-treatment improved the −0.074 mm mass fraction in ground products, and the increase in pulse number effectively enhanced the mass fraction. The values of relative grindability (K1 and K2) increased with the pulse number significantly, whereas their value reduced as the grinding fineness and grinding time extended. A laser particle size analysis showed that the distribution of HVPD pre-treatment products was uniform. The particle size distribution and cumulative distribution curves satisfied the lognormal distribution function and power function, respectively. The Brunauer–Emmett–Teller (BET) analysis indicated that the specific surface area, total pore volume, and the porosity of crushed products were improved effectively by the HVPD pre-treatment. The internal ore structure became loosened, resulting in the decline in the mechanical properties of the ore; this is conducive to improve the grinding efficiency. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) analyses indicated that the grain-boundary breakage was obtained via the HVPD pre-treatment selectivity.