Study of Nanosecond Repetitively Pulsed Discharges Effects on the Technological Properties of Sulfide Minerals from Low-Grade Copper-Nickel Ores

The pulsed energy impacts are promising methods for the pretreatment of refractory mineral raw materials (refractory ores and concentration products) to increase the disintegration, softening, and liberation performance of finely disseminated mineral complexes, as well as to increase the contrast of surface properties for minerals with similar physicochemical and technological properties. In this work, we used analytical electron microscopy, electrode potential testing, sorption and flotation measurements to study changes in the surface morphology, electrochemical, physicochemical, and flotation properties of the natural pyrrhotite, pentlandite and chalcopyrite exposed to non-thermal action of the repetitive high-power nanosecond electromagnetic pulses (HPEMP) and low-temperature plasma of dielectric barrier discharge (DBD) in air at atmospheric pressure. For monomineral flotation of pyrrhotite and pentlandite, we established the optimal mode of preliminary electromagnetic impulse treatment of minerals (t_treat. = 10 s), at which the contrast of their flotation properties increases in the mean on ~20%. Short-term (10 s) treatment of pyrrhotite by DBD caused the shift of its electrode potential to the region of negative values occurred, which causes the effect of a decrease in the pyrrhotite sorption and flotation activity. In the result of short-term (10 s) HPEMP pretreatment of chalcopyrite, the increased floatability of sulfide mineral from 75% up to 92% due to a greater amount of a collector, accumulated at sulfide surface, and its higher electrode potential established. Thus, the advantages of using the short-term (t_treat. = 10−30 s) impulse energy impacts for improvement of the structural, physicochemical and technological properties of iron, copper, and nickel sulfides are shown.