ABSTRACT: The purpose of this study is to develop a high-precision disintegration technology for extracting industrial minerals from rock matrices by applying high-voltage electrical pulses. The electrical disintegration of rock through application of high voltage electrical pulse is one of the effective liberation techniques for producing the high percentage of the monomineral particles in disintegration of mineral aggregates. Circular rock samples of three different types were fractured by applying electric pulses. The microstructure and fractures of the test samples were visualized and analyzed by using microfocus X-ray computed tomography (CT) system. The fracture patterns were simulated by using the dynamic fracture process analysis code and the fragmentation process resulting from electrical pulses were discussed. The influence of rock heterogeneity and sample size effect on the dynamic fragmentation was also discussed.
INTRODUCTION The availability of an efficient breakage method for separating constituents of a rock is of interest to researchers or engineers interested in highly effective comminution for recovering useful minerals, single crystal separation for crystal structure determinations and individual microfossil separation [1-7]. There has been an issue of interest for the last several decades in the use of highvoltage pulse technology for rocks disintegration. The methods of electric pulse disintegration are mainly electrohydraulics and internal breakdown inside bulk solid dielectrics. The first method refers to the generation of an intense shock wave in water from the passage of electrical current through water and the crushing and subsequent constituent separation by the impact of that shock wave on the sample. The second method refers to the passage of electrical current through the rock and the separation of the mineral contents from the rock matrix by preferential current flow along the mineral/rock boundary interface. Rock disintegration using the second method consumes substantially less energy than that using the first method and enhanced effect of liberation of mineral constituents from rock aggregates [1,3]. Almost studies have described the sequence of dielectric events and resultant fractures but do not include a fracture process of rock by high-voltage pulses. The pulsed power technology has been also applied to rock excavation, liberation of micro-fossils, drilling of rocks, oil and water stimulation, casting cleaning, and recycling of products such as concrete, electronic devices and electric appliances [7-9].