## 3 Results and Discussion
### Thermal Characteristics of the Plasma-Chemical Reactor
The mixture for the plasma treatment was prepared and weighed, and its volume was determined. After performing plasma treatment, the melt and unmelted masses were collected and weighed, and the volume of the resulting melt was determined again. It was repeated in every experiment. The amount of clay raw material entering the plasma-chemical reactor was 3.59 kg, and the total amount of the melted fraction collected from the reactor was 3.4 kg. The difference between the material introduced into the reactor and the collected material was 190 g. This amount consists of the gas phase and products that exit the reactor nozzle uncontrollably. According to the obtained results, it was compared and found that the volume of the raw material and the received product differ by a factor of 1:10-1:12. It is also known that by employing plasma technology, it is possible to process complex wastes, consisting of both organic and inorganic components, and ultimately produce stable, completely harmless end-products. At the same time, a significant reduction in the volume of waste is achieved (up to 95%), and the resulting solid residues contain harmful components in a bound, safe state [22; 25; 28]. These vitrified products can be stable for hundreds of years. The electric field strength and gas temperature inside the plasma-chemical reactor during the operation were measured using a specially designed thermocouple system, and the measurement results are shown in Figure 8. Here, \"x\" is the distance from the reactor cover bottom. The heat loss with the cooling plasma torch water was also analyzed in this study. The heat loss by the cooling PT was relatively small; at \(I=50\) A, \(P=45\) kW, and \(x=200\) mm, the heat loss value with the cooling water was only 1.03 kW, which is approximately 2.28% of the total PT power. Such low heat loss values were due to the presence of PT inside the PChR walls protected by a relatively cold refractory material. Figure 7: View of the reactor exhaust gas glow. The obtained results show that, in the processing of zeolites containing aluminum and silicon oxides, the electric field strength and gas temperature inside the reactor are lower than those in clay processing. These results are analogous to the reactor flue-gas measurements. The electric field strength of the arc at the start of the reactor is insignificant. However, during operation, when the operating mode is established and the ambient temperature inside the reactor is high, the voltage reaches 50-60 V (Figure 8). The temperature in the plasma-chemical reactor was measured after 15-20 min of start-up of the reactor. As can be seen from the obtained results (Figure 9), the ambient temperature in the reactor's entire volume is practically stable. The erosive wear of the cathode material in the plasma torch is determined by the arc power (the magnitude of the operating current), the composition of the electrode material, the mode of operation, and the properties of the plasma-forming gas. In our case, the arc power is less than 50 kW at an arc current of 180 A, the cathode material is hafnium, the mode of operation is hot cathode cooling by water, and the plasma-forming gas is air or nitrogen. At such conditions, the erosion of the hafnium cathode is about 0.2 g/h. However, the frequent stopping and restarting of the plasma torch significantly reduce the work resource of its cathode. The results of cathode erosion are described in more detail in our paper [29]. Figure 8: The electric field strength in the operating reactor when working with: 1—zeolites and 2—clay. White dots—after starting the reactor, dark—after 30 min of the start. The airflow through the plasma torch was 1 g/s, and the additional gas flow rate was 2.63 g/s. The PT power was 41 kW. Figure 9: The axial temperature distributions in the operating plasma-chemical reactor worked with: white dots—zeolites, and black—clay. The air flow through the plasma torch was 1 g/s, and the protective gas flow rate was 2.63 g/s. The PT power was 41 kW.