# Development of Electrode of Electric Impulse Chamber for Coal Grinding
## 1 Introduction
Electric impulse method is successfully applied for mineral processing or rock grinding [11; 12; 13; 14], waste recycling [15; 16; 17], and coal preparation for energy use [18]. The article [19] describes experiments on coal grinding in a laboratory vibratory mill to obtain a coal-water suspension (CWS) intended for use as fuel. The study examined the influence of such parameters as grinding duration, composition, and volume of balls on the degree of coal grinding and particle size distribution. Two samples of Polish hard coal with different characteristics, including ash, carbon, oxygen, and vitrinite content, were used in the experiments. The results showed that the vibratory mill effectively ensures coal grinding to the required granulation degree for CWS. The minimum average particle diameter was 12.57 \(\upmu\)m and 13.9 \(\upmu\)m, and the time required to achieve a particle size of less than 100 \(\upmu\)m was 1 h and 1.5 h. It was also found that a decrease in the average particle size leads to an increase in the viscosity of the suspension, which plays an important role in the transportation and storage of CWS. The article [20] considered the destruction of coal rock under the influence of hydraulic pressure and electrical pulses and also developed a model of damage to coal rock. It was found that an increase in voltage from 7 kV to 13 kV leads to a significant increase in damage to coal rock. At the same time, hydrostatic pressure has a smaller effect: with an increase in pressure from 1 MPa to 8 MPa, damage increases by only 6.1%. The most significant cracks with a high degree of penetration are observed at a voltage of 13 kV and a pressure of 8 MPa. The ABAQUS/XFEM module was used to analyze the propagation of cracks in the rock. The coincidence of the results of numerical modeling and laboratory experiments confirms the correctness of the applied approach. The article represents a significant contribution to the development of coal rock destruction technologies. The authors found that electrical pulses in combination with hydraulic pressure significantly increase the efficiency of destruction. The article [21] presented experiments studying the influence of the thickness of carbon samples and the breakdown voltage on the voltage and current characteristics during electrical destruction in air. The experiment was conducted using a specialized system for passing electrical discharges through carbon samples of different thicknesses. The thickness of the carbon layer varied from 5 to 20 mm, and the breakdown voltage from 15 to 40 kV. The energy of the electrical discharge was controlled and altered to study its influence on the destruction process. The results showed that the thickness of the carbon layer significantly affects the energy distribution and the formation of microcracks. Thicker samples required a higher breakdown voltage to initiate effective destruction. Optimum parameters were achieved with a carbon layer thickness of 10-15 mm and a breakdown voltage of 25-35 kV, which ensured the maximum degree of destruction and energy conversion efficiency. The study showed that the correct selection of the breakdown voltage and thickness of the carbon layer allows the minimizing of energy losses, directing most of it to the formation and development of cracks. In addition, electrical destruction reduces the mechanical impact on the rock, which reduces the likelihood of environmental pollution. The choice of electrode material is very important in coal destruction processes. It significantly affects the process of coal destruction using electric discharges, including electric impulse grinding. The article [22] considered the influence of various electrode materials on the coal destruction process. The authors in their work emphasize the importance of choosing the electrode material to optimize the coal destruction process. Various materials were studied, including carbon and metal electrodes.