The process of slow pyrolysis of seven nut shell samples, in a nitrogen-purged atmosphere, has been studied, as well as characteristics of biochar obtained. The heat carrier with a temperature of 400–600 °C (with a step of 100 °C) was supplied indirectly using a double-walled reactor. The heating rate was 60 °C/min. At increased temperature of the heating medium, a decrease in the amount of the resulting carbon residue averaged 6.2 wt%. The release of non-condensable combustible gas-phase compounds CO, CH₄, and H₂, with maximum concentrations of 12.7, 14.0, and 0.7 vol%, respectively, was registered. The features of the obtained biochar sample conversions were studied using thermal analysis in inert (nitrogen) and oxidative (air) mediums at 10 °C/min heating rate. Kinetic analysis was performed using Coats–Redfern method. Thermal analysis showed that the main weight loss (Δm = 32.8–43.0 wt%) occurs at temperatures ranging between 290 °C and 400 °C, which is due to cellulose decomposition. The maximum carbon content and, hence, heat value were obtained for biochars made from macadamia nut and walnut shells. An increased degree of coalification of the biochar samples affected their reactivity and, in particular, caused an increase in the initial temperature of intense oxidation (on average, by 73 °C). While technical and elemental composition of nut shell samples studied were quite similar, the morphology of obtained biochar was different. The morphology of particles was also observed to change as the heating medium temperature increased, which was expressed in the increased inhomogeneity of particle surface. The activation energy values, for biochar conversion in an inert medium, were found to vary in the range of 10–35 kJ/mol and, in an oxidative medium—50–80 kJ/mol. According to literature data, these values were characteristic for lignin fibers decomposition and oxidation, respectively.

The process of advanced aluminum-alumina powders production for selective laser melting was studied. The economically effective method of obtaining aluminum-alumina powdery composites for further selective laser melting was comprehensively studied. The aluminum powders with 10–20 wt. % alumina content were obtained by oxidation of aluminum in water. Aluminum oxidation was carried out at ≤200 °C. The oxidized powders were further dried at 120 °C and calcined at 600 °C. Four oxidation modes with different process temperatures (120–200 °C) and pressures (0.15–1.80 MPa) were investigated. Parameters of aluminum powders oxidation to obtain composites with 10.0, 14.5, 17.4, and 20.0 wt. % alumina have been determined. The alumina content, particle morphology, and particle size distribution for the obtained aluminum-alumina powdery composites were studied by XRD, SEM, laser diffraction, and volumetric methods. According to the obtained characteristics of aluminum-alumina powdery composites, they are suitable for the SLM process.

The two stage technology of porous carbonaceous material obtaining via pyrolysis in inert medium with subsequent activation by steam is well-known. While steam could be a suitable substance for pyrolysis as well, the single-staged technology for waste tires recycling is yet to be developed. A comparative analysis of the characteristics of the carbonaceous materials obtained by the single-staged steam pyrolysis of waste tires was carried out, which could provide theoretical background for development of such technology. The steam pyrolysis was performed in a tubular reactor in an overheated steam medium (500 °C with 5 kg/h mass flow rate). The technical characteristics of the obtained samples were evaluated in context of their potential for further application as absorbent and raw material for the rubber production according to Chemical Abstracts Service No. 1333-86-4. The composition and physical-chemical properties of the obtained samples were studied using BET and thermogravimetric analysis, atomic emission, transmission and scanning electron microscopies, Raman, X-ray diffraction and photoelectron spectroscopies. The results revealed that the structure and properties of all obtained carbonaceous material samples were similar. The samples consisted of amorphous carbon (with a disordered graphite lattice) and contained a significant amount of metal oxides. According to experimental data, zinc was present in the form of ZnO with a binding energy of 1022.4 eV, while sulfur was observed in the form of sulfide and oxysulfide with binding energies of 161.8 and 163.2 eV, respectively. According to electron microscopy, the morphology of samples was represented by a set of spherical agglomerates comprising nanosized particles. According to the BET analysis of the samples, the specific surface area was varieb in range between 52.0 and 66.0 m²/g, the pore volume values were within a range of 0.53–0.87 cm³/g while the average pore size was varied from 412 to 527 Å.

The process of anthracite and its semi-coke combustion in the presence of 5 wt.% (in terms of dry salt) additives of copper salts Cu(NO₃)₂ and Cu(CH₃COO)₂ was studied. The activating additives were introduced by an incipient wetness procedure. The ignition and combustion parameters for coal samples were examined in the combustion chamber at the heating medium temperatures (T_g) of 600–800 °C. The composition of the gaseous combustion products was controlled using an on-line gas analyzer. The fuel modification with copper salts was found to reduce the ignition delay time on average, along with a drop in the minimum ignition temperature T_min by 138–277 °C. With an increase in T_g temperature, a significant reduction in the ignition delay time for the anthracite and semi-coke samples (by a factor of 6.7) was observed. The maximum difference in the ignition delay time between the original and modified samples of anthracite (ΔT_i = 5.5 s) and semi-coke (ΔT_i = 5.4 s) was recorded at a T_g temperature of 600 °C in the case of Cu(CH₃COO)₂. The emergence of micro-explosions was detected at an early stage of combustion via high-speed video imaging for samples modified by copper acetate. According to the on-line gas analysis data, the addition of copper salts permits one to reduce the volume of CO formed by 40% on average, providing complete oxidation of the fuel to CO₂. It was shown that the introduction of additives promoted the reduction in the NO_x emissions during the combustion of the anthracite and semi-coke samples.