The article presents the results of oxidative leaching of lead sludge from copper production in order to extract rhenium into solution. The optimum regimes for product leaching man-made product in the presence of sodium peroxocarbonate Na2CO3·1.5H2O2 has been established: Experimental work was carried out under the following conditions: oxidant consumption 5% by weight of the raw material, leaching temperature 70°C, duration 30–60 minutes, stirring speed 200 rpm, and the ratio of liquid to solid S : L = 1 : 3. The degree of extraction of rhenium into the solution is 95–97%, and the content reaches 500–520 mg/L Re.

This article discusses the decomposition of methane in the temperature range 550–800 °C on low-percentage   monometallic (Ni/g-Al2O3, Co/g-Al2O3) and bimetallic (Ni-Co/g-Al2O3) catalysts. It is shown that the bimetallic catalyst is more active in the decomposition of methane to hydrogen than monometallic ones. At a reaction temperature of 600 °C, the highest methane conversion is 81%, and the highest hydrogen yield of 51% is formed on Ni-Co/g-Al2O3. A complex of physicochemical methods (Scanning Electron Microscope (SEM), X-ray Diffraction (XRD), Temperature Programmed Reduction (TPR-H2), etc.) established that the addition of cobalt oxide to the composition of Ni/g-Al2O3 leads to the formation of surface bimetallic Ni-Co alloys, while the dispersion of particles increases and the reducibility of the catalyst is facilitated, which provides an increase in the concentration of metal particles - active centers, which can be the reason for an increase in the catalytic properties of a bimetallic catalyst in comparison with monometallic ones. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License  (https://creativecommons.org/licenses/by-sa/4.0).

The effect of method preparation on the activity of Fe2O3-NiO/γ-Al2O3 catalyst was investigated in process decomposition of methane. Fe2O3-NiO/γ-Al2O3 catalyst was prepared by impregnation and solution combustion methods. The samples were characterized by X-ray phase analysis (XRD), temperature-programmed hydrogen reduction (TPR-H2), BET and Raman spectroscopy. It has been shown that the method of preparation plays an important role in regulating the textural and morphological properties of catalysts and provides a difference in their catalytic activity. The synthesis of the Fe2O3-NiO/γ-Al2O3 catalyst by the solution combustion method, in comparison with the capillary impregnation method, leads to the formation of a large amount of FeNi and FeAl2O4 solid solutions, which ensured good catalytic activity at high temperatures. The Fe2O3-NiO/γ-Al2O3 catalyst synthesized by the solution combustion method demonstrated good activity with a hydrogen yield of 52% within 150 min of the reaction without any deactivation. According to the results of Raman spectroscopy, graphene-like carbon was obtained on the surface of the catalysts. On the catalyst of Fe2O3-NiO/γ-Al2O3 (СI) synthesized by capillary impregnation, 4‒5 layer graphene on Fe2O3-NiO/γ-Al2O3 (SC)-6-7 layer graphene is formed.

This work is devoted to the study of the activity of monometallic (Fe/Al2O3) and bimetallic (Fe-Mo/Al2O3) catalysts supported to carrier γ- Al2O3. It has been discovered that the bimetallic catalyst is more active than the monometallic catalyst in the methane decomposition reaction. The results of the influence of molybdenum oxide on the activity of Fe/Al2O3 catalyst in the methane decomposition reaction in the temperature range 500-850°C have been obtained. It has been determined that the addition of molybdenum oxide in the amount of 5 wt. % of the iron catalyst composition leads to an increase in the catalytic activity of the sample in the reaction of methanedecomposition to hydrogen at relatively low temperatures. Compared to Fe/Al2O3 on the FeMo/Al2O3 catalyst at a reaction temperature of 750°C, methane conversionincreases from 8% to 98%, hydrogen yield from 5% to 57%. The increased field of activity Fe-Mo/Al2O3catalyst in the decomposition of methane to hydrogen compared to Fe/Al2O3 catalysts is due to an increase in the dispersity of the active phases of the catalyst, as well as the formation of an easily reduced Fe2(MоО4)3 phase, according to XRD, TPR-H2, and BET methods.