Due to the lack of data on the double film Nb-Cd system thermal stability, the effect of thermo-vacuum treatment of cadmium solid solutions in niobium, in intermetallic compound NbCd2 and in cadmium-based alloys on the structure of materials was studied. A step-by-step isochronous annealing at a temperature of 300 and 500°C and a pressure of 1•10-3 Pa was used as the research method followed by tracking changes in the composition and structure by comparing the diffractometric data before and after heat treatment. The amount of cadmium in the coating, the sublimation (evaporation) rate of cadmium from film coatings was determined based on the previously established dependence of the lattice parameter of the body-centered cubic lattice of solid solutions on the composition. As a result, the heating of film coatings (49.0-64.5 at % Cd) represented by solid solutions in high vacuum up to 300°C was founded to be accompanied by the onset of intense degradation of the crystalline niobiumcadmium system due to the diffusion of cadmium atoms to the solid phase-vapor interface and its subsequent sublimation. Coatings from the NbCd2 intermetallic compound which is a degenerate semiconductor and cadmiumbased solid solutions (72.5 and 76.8 at % Cd) including the amorphized phase of the intermetallic compound, after exposure at this temperature are degraded due to the complete transfer of cadmium to the vapor phase by evaporation. Upon thermal exposure to a temperature of 200°C, the structure of solid solutions of cadmium in niobium and the NbCd2 intermetallic compound was stable.

The heterogeneity and local distribution of elements are established as a result of the study of nonferrous metals distribution and the composition of domestic wastes processing concentrate containing 20–40% copper, 40–50% brass, 20–28% zinc and up to 1% aluminium. Metals are mainly concentrated in granules of three types: zinc-based, copper-based and copper–zinc alloy, i.e., brass. The phase composition of these granule types and their structure are determined. Zinc granules are covered with a refractory oxide shell. A distillation processing method for such raw materials based on full state diagrams, including the phase transition of melting pairs of double systems of copper and tin with zinc and lead, is offered. The possibility of a rather complete zinc distillation (over 90%) with the accumulation of other metals in the copper-based alloy, containing more than 96 wt. % of the basic element, has been demonstrated by electric crucible melting in a highly reducing atmosphere. Copper-based alloys, after adjustment for the content of some metals (tin), can be realized as pressure-treated tin bronzes. Copper with the content of impurities corresponding to the standard for blister copper can be electrolytically processed (after dissolution in sulphuric acid) in copper production. Equipment for the implementation of the electro-thermal processing process that provides metal recycling of the metal concentrate is proposed.

Based on the analysis of the operation of vacuum electric furnaces for the processing of dispersed materials by sublimation of volatile components from them, developed by now, and the problems associated with technological processes, a technical solution has been proposed, in which the concentrate is moved due to rheological properties with direct heating by radiation from heater of the surface of the moving and mixing raw materials. Preliminary tests on the sublimation of arsenic sulfide compounds from the gravitational concentrate of the Nezhdaninskoye field with a particle size of 1.0 + 0.63 mm at a temperature of 700°C showed the extraction of arsenic into the vapor phase by more than 99%.

The boundaries of liquid and vapor coexistence fields at pressures of 101.3 and 0.133 kPa were calculated based on the partial vapor pressure values of the components in the Al-Al2Se3 and Al2Se3-Se partial systems. The vapor pressures of the more volatile aluminum selenide and selenium in the above systems were determined by the isothermal version of the boiling-point method. The partial pressures of the fewer volatile components were determined by numerical integration of the Gibbs–Duhem equation. The partial and integral values of the thermodynamic functions of the formation and evaporation of solutions were calculated based on the values of the partial vapor pressure of the system components. Based on the analysis of the complete phase diagram, it was found that the purification of aluminum by vacuum distillation in a single operation can remove aluminum selenide and selenium at an appropriate rate. The distillation of selenium from melts in vacuum in the whole concentration range of the Al2Se3-Se system will proceed from the mixture of the solution with Al2Se3 cryst., with accumulation of the latter in the distillation residue.

The tin vapor pressure, partial and integral thermodynamic functions of mixing and vaporization of Sn-Zn melts are calculated based on the zinc vapor pressure values determined by the boiling point method. The formation of alloys proceeds with heat absorption and an attendant increase in disorder relative to an ideal solution. The peak integral entropy of mixing corresponds to ~60 at % Zn and is 3.25 ± 0.15 kJ/mol. The extreme integral excess entropy of mixing relates to the equimolar composition and is 2.22 ± 0.38 J/(mol K). The tin-zinc phase diagram is supplemented with liquid-vapor coexistence fields at the atmospheric pressure (101.3 kPa) and at 100 and 1 Pa, which fields imply that, regardless of pressure, the vapor phase is represented virtually by elemental zinc solely. The positions of boundaries of equilibrium vapor-liquid fields indicate the absence of technological difficulties and the possibility of complete distillation separation of the Sn-Zn system into constituent metals. The process limitation consists in the lowest pressure of 30 Pa that prevents the crystallization of the solid zinc solution from the liquid phase. The reason behind the increased tin content in the condensate at the final stage of zinc evaporation is the high intensity of its transfer to the vapor phase and the entrainment of melt microdroplets by the vapor flow.