Heating and fracture spatiotemporal evolution characteristics of key granite minerals under microwave irradiation

Abstract

Microwave fracturing offers significant potential for efficient hard rock fragmentation. This study investigates real-time heating and fracture characteristics of ten granitoid minerals under 2 kW microwave irradiation for 3 min. Chlorite, amphibole, and altered plagioclase were identified as highly microwave-sensitive, exhibiting high mass and P-wave velocity decay, rapid heating rates (>2.5 °C/s) and violent rupture. Mineral surface temperature non-uniformity, quantified by the coefficient of variation (V_T), evolved through distinct increasing, decreasing, and stabilizing phases, reflecting shifts in dominance between heat accumulation and transfer. Temperature gradients revealed the spatial relationship between hotspots and rupture points, with shallow melting influencing surface temperature distribution. Undamaged minerals exhibited significant temperature gradient spatiotemporal variability but ultimately stabilizing. These results enable prediction of microwave heating behavior in hard rocks containing analogous minerals and enhance our understanding of microwave-induced weakening mechanisms.

Keywords

microwave irradiation / minerals / microwave sensitivity / temperature gradient

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