The results of experiments on the impact of high power electromagnetic pulses (EMP) on the metal alloy melts are discussed. A generator with the following pulse parameters: the amplitude of 10 kV, the duration of 1 ns, the leading edge of 0.1 ns, repetition rate of 1 kHz was used for pulse electric treatment of metal melts. The maximum network input of the generator equals 100 watts. The treatment was carried out in a furnace immediately before casting. The treatment of the melt by electromagnetic pulses is conducted for 10-15 minutes. Comparative analysis of treated and untreated samples showed a change in structure, density, strength, ductility, and toughness of the cast metal. The mechanism of stepping impact on the metal melts was discussed. Analysis of the results of other external physical melt impact methods showed that the overall match is observed with the results of the ultrasonic treatment of metals. Therefore, the hypothesis of the pulse ultrasonic shock wave generation at the front was accepted as the basis-hypothesis for the mechanism of the impact of electromagnetic pulses on the melt. In the theoretical part of the paper a model of electromagnetic pulses conversion in acoustic pulses is proposed.

The paper presents the results of a relatively new method of external action on melts developed by the authors. The essence of the technology is the impact on melts before casting with electromagnetic pulses (EMP) of short duration (1 ns) and with high pulse power (2 kW). To create electromagnetic pulses, a generator with the following characteristics was used: pulse amplitude of 10 kV, the leading edge of the pulse was 0.1 ns, pulse duration of 1 ns, pulse repetition rate at 1 kHz, and a calculated pulse power of 2 MW. A distinctive feature of the generator used was its low power consumption of 50 Watts. The results of processing low-melting melts of the Al–50Pb, Bi–38Pb, and Bi–18Sn–32Pb systems presented in the work indicated that EMP treatment led to the occurrence of equilibrium crystallization of the metal, increasing its density. In addition to the experimental results, a theory is provided to explain the mechanism of the influence of pulse processing on the properties of metals of these and other systems previously studied by the authors.

Questions of influence of nanosecond electromagnetic impulses on melts of metals are considered in the article. The analysis of action of impulses on electromagnetic hashing and thermal conditions of a melt showed their small influence. Mechanical (acoustic) action is chosen as the main one. Formulas and values for coefficients of transformation of electromagnetic field to the acoustic one for a number of metals are given. The transformation model in the form of the wave of current running on the radiator is offered. Comparison of action of electromagnetic impulses on melts showed that emergence of acoustic vibrations is the main thing. The theory of contactless transformation of electromagnetic waves in acoustic ones is considered. Comparison with experiments is given. The model of contact electro-pulse processing of metal melts in the form of transition of an electromagnetic wave to acoustic is offered. Acoustic waves change structure of a melt, condition of a crystallization of a melt and improve properties of the hardened metal.

Experimental results for nanosecond electromagnetic impulses (NEMI) impact on precious metals leaching process from sulphidic ores are presented. A possibility of an intensification of leaching process of Au, Ag, Cu is established. The extraction of silver increases by 70 %, gold – by 40 %. The samples of sulphidic ores from the pit of JSC NPF "Bashkir gold mining company" are taken as objects of research. The use of economic electronic generators is suggested herein. They create impulses of 1 nanosecond, the front of 0.1 nanoseconds, amplitude of 6-15 kV impulses, 1 kHz frequency of repetition, consumed power from an electric network is less than 100 W. Energy in one impulse is 10–3 J. The pulse field changes the valence of metals of impurity towards decrease. It changes the current of chemical reactions in a mineral matrix. The local heating of the precious metals interspersed particles and destruction of a mineral matrix are also possible.