Numerical modeling and simulation of the electric breakdown of rocks immersed in water using high voltage pulses
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ORIGINAL ARTICLE
Numerical modeling and simulation of the electric breakdown of rocks immersed in water using high voltage pulses Yuansheng Li . Jun Liu . Bingyang Feng . Xingru Zhang . Mengyu Zhang . Haolong Xiao . Mengbing He . Fengnian Shi
Received: 29 July 2020 / Accepted: 21 October 2020 Ó Springer Nature Switzerland AG 2020
Abstract Selective breakdown of mineralized particles by using high-voltage pulses (HVP) has been reported, yet its mechanisms are not fully understood, and the HVP setting factors affecting its efficacy in ore pre-concentration for the mining industry are not established. This study investigates the electro-dynamic mechanisms of electric breakdown by using the time-transient dielectric breakdown model and the finite-difference numerical method. Monte-Carlo method with random sampling is applied to calculate breakdown probabilities. The model and the selected parameters have been validated by the published experimental data of the electric breakdown of mineralized synthetic particles. The simulations of pulse rising time from 150 ns to 1 ls showed that the HVP breakdown threshold of rock particles gradually increased as the pulse rising time decreased. This suggests that to minimize the mis-breakdown of barren rocks in the HVP-enabled ore pre-
concentration application, it is important to use a generator with a short pulse rising time. Shorter pulses also led to a higher probability of the internal breakdown of the mineralized particles. The simulations indicate that inhomogeneity of conductivity in an ore particle caused the streamers to bend toward the area of inclusion with high conductivity in a host rock matrix, which increased the probabilities of the breakdown of this mineralized particle. This phenomenon was more pronounced as conductivity rose. High-conductivity inclusions can reduce the minimum voltages required for the breakdown of the mineralized particles. Keywords Electro-dynamic breakdown Numerical simulation High-conductivity inclusion Breakdown threshold
1 Article highlights Y. Li J. Liu B. Feng X. Zhang M. Zhang H. Xiao M. He (&) State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan 430074, Hubei, China e-mail: [email protected] F. Shi The Julius Kruttschnitt Mineral Research Centre, Sustainable Minerals Institute, The University of Queensland, Brisbane, QLD 4068, Australia
1. The time-transient model validated by the published data is used to simulate HVP breakdown processes of rocks and ores. 2. Short pulse rising time is a key to minimize the mis-breakdown of barren rocks and improve the selective breakdown of ores.
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Geomech. Geophys. Geo-energ. Geo-resour. (2021)7:1
3. High-conductivity inclusion in the host rock matrix can enhance the internal breakdown probability of the ore particles.
2 Introduction The destruction of solids using high-voltage pulses (HVP) is a promising technology in the field of pulsed power. It has been used in many indus
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