This paper reviews current research in high pulsed power technologies for processing of precious metals containing refractory ores and natural mineral aggregates. This is a branch of experimental engineering physics that critically depends on national priority research projects for its dynamic development. The aim of the manuscript is to show progress in the study of nanosecond processes involved in the disintegration and breaking-up of mineral complexes with fine disseminated precious metals. The manuscript presents results of theoretical and experimental studies of the mechanisms of the nonthermal action of high-power electromagnetic pulses with nanosecond leading edge, pulse duration, and high electric field strength on natural mineral media. Experimental data are presented to confirm the formation of breakdown channels and selective disintegration of mineral complexes as a result of pulse irradiation. This makes for efficient access of lixiviant solutions to precious metal particles and enhances precious metal recovery into lixivia during leaching. The paper shows the advantages of high-energy pulse treatment that provides a stable gain in valuable components recovery (5–80% gain for gold and 20–50% for silver) and at the same time helps to reduce energy consumption and cost of products in the processing of resistant gold-containing ores and beneficiation products from Russian deposits. X-ray photoelectron spectroscopy was used for determining the relationship between electromagnetic pulses energy and the surface chemical composition for pyrite and arsenopyrite. It has been concluded that impulsive treatment influences oxidation and hydrophobicity of the minerals and, therefore, it allows for the control of the hydrophobic–hydrophilic mineral surface balance.

X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy are used to study the change of the surface layers and chemical state of atoms on galena surface after treatment by...

The main results of the theoretical and experimental studies on the directional modification of the surface phase composition as well as the structural, chemical and process properties of non-ferrous, rare and noble metals under physicochemical and pulse energy impact are presented. The main mechanisms of the surface micro- and nanophases formation for the increase in the yield and quality of concentrates during processing of rebellious ore with the complex material constitution are revealed. The rational parameters and conditions for preliminary treatment of sulfide minerals by high-power (high-voltage) nanosecond electromagnetic pulses in order to increase the flotation separation selectivity of sulphides with the similar physicochemical properties, such as pyrite–arsenopyrite, pyrrhotite–pentlandite and chalcopyrite–sphalerite, due to contrast changes in the chemical and phase surface composition, hydrophobicity, sorption activity and floatability of minerals, are determined and experimentally proved. The high efficiency of application of the pulsed energy impact and electrochemically treated water systems is demonstrated in terms of the directional change in the properties of rock-forming minerals of kimberlites and preservation of diamond crystals during milling. The described results confirm the effectiveness of the electrochemical treatment application to mineral suspensions and aqueous systems under leaching of sulphide copper–zinc ore and rebellious gold-bearing concentrate.The study has been supported by the Academician Chanturia School, Grant NSH-7608.2016.5.The authors appreciate participation of Candidate of Engineering Sciences V. G. Minenko, Candidate of Geologo-Mineralogical Sciences E. V. Koporulina, Candidate of Engineering Sciences E. S. Zhuravleva and Leading Engineer N. E. Anashkina, IPKON RAS.

Using X-ray photoelectron spectroscopy, the authors analyze the change in the surface layer composition and chemical state of atoms of chalcopyrite and sphalerite as a result of treatment by high-power nanosecond electromagnetic pulses. General regular patterns and distinctions of modification of the mineral surface and floatability under high-power pulse treatment are found. The research findings are supported by the results of experimental improvement gained in selective separation of sulfides after the high-power nanosecond electromagnetic treatment.

High-power nanosecond electromagnetic pulses cause changes in the chemical and phase surface composition of sulfide minerals (pyrrhotite and pentlandite) and their sorption, flotation, and chemical activities. The influence of the conditions and parameters of the electric-pulse effect on the change in the amount of elemental sulfur and iron oxide on the surface of mineral particles, as well as the concentration of iron and sulfoxide ions in the aqueous mineral suspension, has been studied. The parameters of preliminary pulsed treatment of pyrrhotite and pentlandite that lead to improvement of flotation separation of minerals have been determined.

In Russia and globally, pulsed power technologies have been proposed based on the conversion of energy into a short-pulsed form and exposing geomaterials (minerals, rocks, and ores) to strictly dosed high-power pulsed electric and magnetic fields, beams of charged particles, microwave radiation, neutrons and X-ray quanta, and low-temperature plasma flows. Such pulsed energy impacts are promising methods for the pretreatment of refractory mineral feeds (refractory ores and concentration products) to increase the disintegration, softening, and liberation performance of finely disseminated mineral complexes, as well as the contrast between the physicochemical and process properties of mineral components. In this paper, we briefly review the scientific foundations of the effect of both high-power nanosecond electromagnetic pulses (HPEMP) and dielectric barrier discharge (DBD) in air on semiconductor ore minerals (sulfides, rare metals minerals) and rock-forming dielectric minerals. The underlying mechanisms of mineral intergrowth disintegration and changes in the structural and chemical states of the mineral surface when exposed to HPEMP and DBD irradiation are discussed. The high performance and potential limitations of pulsed energy impact and low-temperature plasma produced by DBD treatment of geomaterials are discussed in terms of the directional change in the process properties of the minerals to improve the concentration performance of refractory minerals and ores.