Effect of high voltage pulse treatment on the surface chemistry and floatability of chalcopyrite and pyrite

Zuo, Weiran; Li, Xinfeng; Shi, Fengnian; Deng, Rongdong; Yin, Wanzhong; Guo, Bao; Ku, Jiangang

doi:10.1016/j.mineng.2019.106170

Cited by 18 publications

(3 citation statements)

References 34 publications

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“…Smaller values of the weighted average of amber particle size obtained by grinding in the alcoholic medium can be explained by the lower value of the dielectric constant of alcohol. The dielectric constant of alcohol is 25.3, and the dielectric constant of water is 80 [15]. Thus, due to higher amplitudes of discharge pressures formed in a liquid with lower dielectric constant, we obtained such a result of amber grinding, because the main factor deciding on the destruction of the material is the amplitude of pressure pulse, not the pulse energy.…”

Section: Resultsmentioning

confidence: 87%

Archive of Mechanical Engineering

Chornyi

Kharchenko

Mysiura

et al. 2021

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Investigation of particle size distribution of grinded amber by electropulse discharges in a liquid mediumThe article presents the study results of electropulse grinding of amber in aqueous and alcoholic media at different amounts of supplied energy.Description of the electropulse grinding laboratory installation, the mechanism of the destruction process of amber particles and methods of statistical processing of experimental data are given. It was established that alcohol medium has a greater impact on the efficiency of crushing than water. Thus, under the same conditions of energy supply, in the aqueous medium the weighted average particle size of amber was 601.6 ± 688.9 µm, and in an alcohol medium -368.0 ± 269.6 µm. In an aqueous medium, the particle size decreased to 1/13.6 of raw sample, and in an alcoholic medium to 1/22.3 of raw sample compared to the initial size of raw amber. We found that in the aqueous medium the ratio of large to small fractions is mainly the same with the coefficient of alignment of particles with a size of 1.09. In an alcoholic medium, this ratio significantly differs, with the coefficient of alignment of amber particles of a size of 1.67 with the amount of supplied energy of 125 kJ.

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Section: Resultsmentioning

confidence: 87%

Archive of Mechanical Engineering

Chornyi

Kharchenko

Mysiura

et al. 2021

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“…Simultaneously, shock waves may subject the rock to a combined tension–compression triaxial stress state (Dai, 2001; Li et al, 2012) [ 26 , 27 ]. Furthermore, under a high-voltage electropulse, the rock is not only subjected to dynamic loading such as shock wave, but also high-temperature plasma and explosive products in the form of quasi-static effects that continue to damage the rock in different time scales (Ma and An, 2008; Vogler et al, 2020; Zuo et al, 2020) [ 28 , 29 , 30 ]. Meanwhile, the heterogeneity of the rock causes a change in the distribution of stress, which may lead to fractal cracking or secondary cracking (Yudin et al, 2019; Kutter and Fairhurst, 1971) [ 9 , 31 ].…”

Section: Introductionmentioning

confidence: 99%

Mechanism Analysis of Rock Failure Process under High-Voltage Electropulse: Analytical Solution and Simulation

et al. 2022

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This work aims to investigate and analyse the mechanism of rock failure under high-voltage electropulses in order to evaluate and increase the efficiency of high-voltage pulse technology in geological well drilling, tunnel boring, and other geotechnical engineering applications. To this end, this paper discusses the equivalent circuit of electric pulse rock breaking, the model of shock wave in electro channel plasma, and, particularly, the model of rock failure in order to disclose the rock failure process when exposed to high-voltage electropulse. This article uses granite as an example to present an analytical approach for predicting the mechanical behaviour of high-voltage electropulses and to analyse the damage that occurs. A numerical model based on equivalent circuit, shock wave model, and elasto-brittle failure criterion is developed for granite under electropulse to further examine the granite failure process. Under the conditions described in this study, and using granite as an example, the granite is impacted by a discharge device (Marx generator) with an initial voltage U0 that is 10 kV and a capacitance F that is 5 µF before it begins to degrade at about 40 µs after discharge, with the current reaching its peak at approximately 50 µs. The shock wave pressure then attains a peak at about 70 µs. Dense short cracks form around granite and the dominant cracks grow to an average length of about 20 cm at around 200 µs. The crack width dcr is predicted to be approximately 1.6 mm. This study detects dense cracks in a few centimetres surrounding the borehole, while around seven dominant cracks expand outward. The distribution of the length of the dominating cracks can be inhomogeneous because of the spatial heterogeneity of granite’s tensile strength, however the heterogeneity has an insignificant effect on the crack growth rate, total cracked area, or the number of main cracks. The mechanism of rock failure under electropulse can be well supported by the findings of numerical simulations and analytical studies.

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“…HPVD refers to the accumulation of low power energy for a period of time and then release high power energy for a short time [1]. In the mid-20th century, the Soviet Union has used the principle of hydroelectric effect to dismantle concrete foundation, but it was not popularized [2].…”

Section: Introductionmentioning

confidence: 99%

Research on Crushing Concrete Members by High‐Voltage Pulse Discharge Technology

Wang

2021

Advances in Civil Engineering

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High-voltage pulse discharge (HVPD) is an energy-saving, efficient, and green technique, which has broad prospects in concrete crushing. The finite element models of the concrete beam, slab, and column segments were established with ANSYS/LS-DYNA finite element software. Based on the principle of equal impact pressure, the shock wave generated by the fuse explosion caused by HVPD of 50 kJ is equivalent to the impact load of explosive blasting, and the stress of concrete beam segment was analyzed. The finite element models of the concrete beam sections were established to investigate the influence of diameter and spacing of the holes on the crushing effect of concrete beam segments. The width × height of each beam segment is 400 mm × 800 mm, and there are six types of beam segment length: 600 mm, 700 mm, 800 mm, 900 mm, 1000 mm, and 1100 mm. Two holes are drilled vertically on the surface of the width × length of each beam segment. The spacing of holes corresponding to beam segments of each length type is 200 mm, 300 mm, 400 mm, 500 mm, 600 mm, and 700 mm, respectively. The hole depth of each beam segment is 650 mm, and there are three types of aperture: 30 mm, 50 mm, and 70 mm. The analysis results show that the crushing effect of concrete beam segments increases with the increase of aperture and the decrease of hole spacing. According to the crushing effect of the beam segments, the aperture of 50 mm, the spacing of 400 mm, and the hole end (edge) spacing of 250 mm were determined as the optimal hole layout scheme. The finite element models of concrete slabs and columns were established. The square concrete slab thickness is 140 mm and side length is 700 mm, 800 mm, and 900 mm, respectively. Double-row holes were arranged in the slabs and the aperture is 50 mm and the hole spacing is 200 mm, 300 mm, and 400 mm, respectively. The section sizes of concrete columns are 500 mm × 500 mm, 600 mm × 600 mm, and 700 mm × 700 mm, respectively, and the aperture is 50 mm and the hole distance is 400 mm. According to the results of analysis, the optimal hole distribution scheme of concrete slab and column is chosen as the aperture of 50 mm and hole distance of 400 mm. The principle of the layout of multirow holes is that the spacing of row is not more than 400 mm, and the margin is not more than 250 mm.

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Effect of high voltage pulse treatment on the surface chemistry and floatability of chalcopyrite and pyrite

Cited by 18 publications

References 34 publications

Archive of Mechanical Engineering

Archive of Mechanical Engineering

Mechanism Analysis of Rock Failure Process under High-Voltage Electropulse: Analytical Solution and Simulation

Research on Crushing Concrete Members by High‐Voltage Pulse Discharge Technology

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