Effect of microwave pretreatment on grinding and flotation kinetics of copper complex ore

The present study initially investigates the kinetics of microwave-assisted grinding and flotation in a porphyry copper deposit. Kinetic tests were conducted on untreated and microwave-irradiated samples by varying the exposure time from 15 to 150 s. Optical microscopy, energy-dispersive X-ray spectroscopy, and scanning electron microscopy were conducted to determine the mineral liberation and particle surface properties, and to perform mineralogical analyses. Results showed that the ore breakage rate constant monotonically increased by increasing the exposure time, particularly for the coarsest fraction size (400 µm) due to the creation of thermal stress fractures alongside grain boundaries. Excessive irradiation time (>60 s) led to the creation of oxidized and porous surfaces along with a dramatic change in particle morphologies that result in a substantial reduction of chalcopyrite and pyrite flotation rate constants and ultimate recoveries. We concluded that MW-pretreated copper ore was ground faster than the untreated variety, but the two types have slightly similar floatabilities.