Microwave heating of dry and water saturated basalt, granite and sandstone

Peinsitt, T.; Kuchar, F.; Hartlieb, Philipp; Moser, Peter; Kargl, Hubert; Restner, Uwe; Sifferlinger, Nikolaus August

doi:10.1504/ijmme.2010.031810

Cited by 93 publications

(21 citation statements)

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“…Therefore, temperature gradients would be produced in the irradiated rock, reducing the strength of the rock by yielding micro-and macro-cracks [10][11][12]. The water content, the size and location of grains, can affect the initiation and propagation of cracks [13,14]. Also, the microwave radiation conditions, including the microwave I power level, the distance to rock, and the radiation time, were also shown to affect the intensity and distribution of temperature [12,15].…”

Section: Introductionmentioning

confidence: 99%

Structural failure process of schistosity rock under microwave radiation at high temperatures

et al. 2019

Frattura Ed Integrità Strutturale

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The effects of high temperature induced by microwave radiation on the schistosity structural rock were investigated. A 1.45 kW commercial microwave system was employed to irradiate specimens to a designed temperature (300 − 800 °C) for 15 minutes. Cracking and local melting initially appeared in the biotite enrichment area at 500 °C. Macro-cracks in the dark area were parallel to the schistosity trend, owing to the weak connection in a direction perpendicular to the schistosity plane. The composition of the rock did not significantly change before and after microwave radiation. The diffraction peak intensity of the biotite decreased with temperature increase, owing to melting. The average peak stress decreased significantly with increasing temperature. It is concluded that the high temperature induced by microwave radiation promotes hard rock breakage and the schistosity structure of rock significantly affects the cracking pattern.

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Section: Introductionmentioning

confidence: 99%

Structural failure process of schistosity rock under microwave radiation at high temperatures

et al. 2019

Frattura Ed Integrità Strutturale

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“…granite, basalt, norite, gabbro et.al) would generate heat and form uneven temperature distribution internally under microwave irradiation [17][18][19]. High temperatures would cause microscopic or macroscopic cracks even melting in rocks to reduce mechanical strength of rocks, such as point load and uniaxial compression strength [20][21][22]. The power level, irradiation time, the water content and the parameter of rock all had an influence on breakage effects [18,19,23].…”

Section: Introductionmentioning

confidence: 99%

The thermal damaging process of diorite under microwave irradiation

Yuan

Zeng

et al. 2018

Frattura Ed Integrità Strutturale

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Laboratory tests have been conducted to investigate the effects of thermal damage on diorite under microwave irradiation. The sample rocks were heated to high temperature range of 300 to 800 ℃ in a single-mode microwave furnace. The experimental results show that the rocks started to crack at 500 ℃ and completely disintegrated at 700 ℃. The intensities of quartz diffraction peaks were almost unchanged while the diffraction peak intensity of hornblende gradually decreased with temperature increasing. In addition, the chlorite diffraction peak disappeared at 500 ℃. The compressive strength of the sample decreased to 40% at 600 ℃ and it approached zero at 700 ℃. In this paper, the possible reasons for the thermal effects on the fracture of diorite were discussed, which can be related to water evaporation,

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“…Laboratory tests mainly concerning comminution have been performed in multi-mode microwave ovens (e.g. Walkiewicz et al, 1991 , Kingman and Rowson, 1998 , Amankwah et al, 2005 , Peinsitt et al, 2010 , Hartlieb et al, 2012 , Hassani et al, 2012 ) and in a single-mode cavity ( Kingman et al, 2004 ). Substantial weakening of the rocks has been observed whereupon the energy consumption was significantly lower in the single-mode cavity.…”

Section: Introductionmentioning

confidence: 99%

Microwave propagation and absorption and its thermo-mechanical consequences in heterogeneous rocks

Meisels

Toifl

Hartlieb

et al. 2015

International Journal of Mineral Processing

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A numerical analysis in a two-component model rock is presented including the propagation and absorption of a microwave beam as well as the microwave-induced temperature and stress distributions in a consistent way. The analyses are two-dimensional and consider absorbing inclusions (discs) in a non-absorbing matrix representing the model of a heterogeneous rock. The microwave analysis (finite difference time domain — FDTD) is performed with values of the dielectric permittivity typical for hard rocks. Reflections at the discs/matrix interfaces and absorption in the discs lead to diffuse scattering with up to 20% changes of the intensity in the main beam compared to a homogeneous model rock. The subsequent thermo-mechanical finite element (FE) analysis indicates that the stresses become large enough to initiate damage. The results are supported by preliminary experiments on hard rock performed at 2.45 GHz.

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Microwave heating of dry and water saturated basalt, granite and sandstone

Cited by 93 publications

References 0 publications

Structural failure process of schistosity rock under microwave radiation at high temperatures

Structural failure process of schistosity rock under microwave radiation at high temperatures

The thermal damaging process of diorite under microwave irradiation

Microwave propagation and absorption and its thermo-mechanical consequences in heterogeneous rocks

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