No 2 (2025)

The conditions of formation and metalliferous content of Lower-Middle Miocene coal deposits on the southwestern margin of the Zeya–Bureya basin are considered. Their formation took place within the Priamursky depression, bounded on the west by the Greater Khingan and on the east by the Kostyukovo–Blagoveschensk uplift system. For the first time, mineralogical composition, geochemistry of coal, and their combustion products were studied in detail. Uneven accumulation of REY (REE + Y), rare metals, non-ferrous metals, and noble metals was shown, which is largely related to the variety of the composition of feeding provinces that border the depression. The genetic types of enrichment of REE were identified, and the prospects of their use as raw materials for extraction during coal burning were determined.

In this work the possibility of catalytic hydrotreating of petroleum sintering additive (PSA) with sulphur content of 4–6 wt % has been experimentally shown and the method of catalytic hydrotreating has been proposed. It was proposed to use a solvent (toluene) to prepare the feedstock for the hydrotreating process. Under the conditions of 390°C, 100 atm, LHSV = 0.5 h^–1 on CoMoNi catalyst deposited on aluminium oxide, a product with 1.72 wt % sulfur and retaining sintering properties relative to the original PSA was obtained. Hydrotreated PSA belongs to G15 Grey-King coke and has a high sinterability index of 1 : 5 (80).

The study of the processes of sorption of various chlorophenolic compounds from aqueous solutions by high-moor peat and products of its sequential disassembly was carried out. Compounds with different degrees of chlorine substitution were used as model chlorophenolic compounds: 2,4-dichlorophenol, 2,4,6-trichlorophenol, and pentachlorophenol. According to the results of chromatographic determination, it was established that the degree of binding of chlorophenolic compounds by the studied materials increases in the series: pentachlorophenol (10.9–15.5 μg/g peat, or 31.4–44.7%)–2,4,6-trichlorophenol (16.3–26.3 μg/g peat, or 47.6–76.7%)–2,4-dichlorophenol (19.6–34.6 μg/g peat, or 56.8–100%). An increase in the pH medium leads to an increase in the degree of dissociation of chlorophenolic compounds and their mobility, and ultimately to a decrease in the degree of their binding. The effect of pH is most pronounced for 2,4-dichlorophenol, which is characterized by the maximum pKa value.

The Ni–Cu/Al₂O₃ catalysts used for the synthesis of nanofibrous carbon were prepared by the solution combusion method using sucrose as a fuel. The effect of different sucrose contents on the composition and textural characteristics of the resulting catalysts was studied. Catalyst samples were tested in a quartz flow reactor at atmospheric pressure and a temperature of 550°C (reaction medium — methane) for 6 h. The effect of organic fuel content on the performance of the catalyst precursor in the synthesis of nanofibrous carbon was studied. The resulting catalyst was a powder with a specific surface area of up to 128 m²/g.

The physicochemical properties of humic acids in lower alcohols and water–alcohol solutions have been studied. Hymatomelanic acids extracted with methanol, ethanol, n-propanol or isopropanol from native humic acids differ in structure and properties. Aqueous solutions of sodium salts of humic acids exhibit pronounced surface-active properties at the interface with air. Critical concentrations of aqueous solutions of lower alcohols have been established, at which the stability of humic acid salts is disrupted.