The effect of high voltage electrical pulses on iron ore comminution to improve desulfurization flotation recovery

In this research, the effect of employing high voltage electrical pulse (HVEP) on crushing to improve the recovery of iron ore desulfurization was investigated compared to mechanical crushing. To determine the effect of mechanical and electrical crushing, jaw crusher, cone crusher, and high voltage electrical pulse crusher (50Kv) were applied. The results indicated that coarser particles with fewer slimes are produced in the initial crushing stage using electric pulses. Selective separation mechanism from the boundary of the particles based on different dielectric constants, was the main difference between the HVEP method and mechanical crushing. In the flotation process of sulfide minerals crushed by an electric pulse crusher, recovery of the sample was 10.6% higher, and the grade of sulfur in flotation residue of iron ore concentrate was approximately 58% lower than the sample which was undergone through the initial mechanical crushing stage. The obtained results evidenced 37.5% increase in flotation kinetics constant while electric pulse crushing is preferred to mechanical crushing. For mineralogical studies, microparticles (-38 microns) were studied in the pulp phase of the sample, and the results proved that in the electric pulse crushing of the microparticles, they are dispersed, and there is a distance between them, while in the mechanical approach they are formed in the shape of agglomerated particles. This phenomenon leads to better preparation and further possible contact of pyrite particles with air bubbles, which increases flotation kinetics and the recovery of sulfur merely when electric pulse crushing was employed.