The effect of microwave pretreatment on the liberation of a copper carbonatite ore after milling

The effects of microwave treatment on the liberation spectrum of a rod-milled South African carbonatite ore are presented based on quantitative mineralogical analysis. The treated ore was processed for 0.5 s at 10.5 kW in a single mode microwave cavity in batches of 1 kg. The ore selected for microwave treatment was a sample from a tertiary crusher product stream feed to a rod mill. The treated and untreated ore were subsequently grinded to 80%–800 μm. The microwave treated ore showed a significant increase in the amount of liberated copper minerals in the relatively coarse particle size range (106 to 300 μm). Similar significant shifts in the liberation spectra were noted for all the minerals in the ore. It is inferred that microwave treatment induces changes in the fracture pattern, favouring liberation of microwave susceptible minerals at larger particle sizes.