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

Authors: Thomas Peinsitt, Friedemar Kuchar, Philipp Hartlieb, Peter Moser, Hubert Kargl, Uwe Restner, Nikolaus A. Sifferlinger

Addresses: Sandvik Mining and Construction Gmbh, Alpinestrasse 1, A-8740 Zeltweg, Austria. ' Institute of Physics and Department Mineral Resources and Petroleum Engineering, University of Leoben, Franz Josef Strasse 18, A-8700 Leoben, Austria. ' Department Mineral Resources and Petroleum Engineering, University of Leoben, Franz Josef Strasse 18, A-8700 Leoben, Austria. ' Department Mineral Resources and Petroleum Engineering, University of Leoben, Franz Josef Strasse 18, A-8700 Leoben, Austria. ' Sandvik Mining and Construction Gmbh, Alpinestrasse 1, A-8740 Zeltweg, Austria. ' Sandvik Mining and Construction Gmbh, Alpinestrasse 1, A-8740 Zeltweg, Austria. ' Sandvik Mining and Construction Gmbh, Alpinestrasse 1, A-8740 Zeltweg, Austria

Abstract: The heating of rocks with low to medium microwave absorption strength and its dependence on the water content is investigated in a 3 kW microwave oven at 2.45 GHz. Sandstone, granite, and basalt are chosen as the rock materials where basalt has the relatively highest absorption strength in the dry state. The effect of the microwaves at low energy input is investigated by measurements of the uniaxial compressive strength and the ultrasound velocity. The latter is found to be more reliable and is used for deducing trends caused by microwave irradiation. The largest effect due to the water content is observed in sandstone. At high energy input in basalt the interior melts and the samples break.

Keywords: microwave heating; dry rocks; water content; uniaxial strength; ultrasound velocity; water saturated rocks; basalt; granite; sandstone; rock heating; absorption strength; microwave irradiation.

DOI: 10.1504/IJMME.2010.031810

International Journal of Mining and Mineral Engineering, 2010 Vol.2 No.1, pp.18 - 29

Published online: 24 Feb 2010 *

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