The results of the thermodynamic modeling are presented for oxidizing roasting of refractory molybdenite (MoS2) with magnesite (MgCO3). The phase and chemical compositions of the MoS2–MgCO3–O2system...

The world reserves of oxidized lead–zinc ores are large, but their processing faces significant difficulties due to their refractory nature. This paper presents a novel approach to the preparation of refractory oxidized lead ores for flotation. The proposed method is based on the co-roasting of oxidized lead-bearing ores from the Ozernoye polymetallic deposit (Western Transbaikalia, Russia) with fine-grained sulfide lead–zinc ore sourced from the same deposit and the addition of calcium oxide. This method allows for the activation of mineral complexes, the sulfidation of oxidized lead–zinc minerals, and the minimization of the amount of sulfur dioxide gas emitted. Co-roasting oxidized lead–zinc ore with sulfide ore (10–30 wt. pct) at 650–700 °C has been shown to result in the selective oxidation of pyrite and sulfidation of oxidized lead and zinc minerals. The proposed method of processing polymetallic ores is capable of simultaneously involving not only oxidized lead–zinc ores but also refractory sulfide ores, thereby extending the operational lifespan of the mining enterprise and reducing the environmental impact.

This article presents the results of research on the sintering of molybdenite concentrate with magnesium-containing natural additives — brucite (Mg(OH)₂) and magnesite (MgCO₃). Physical and chemical properties of initial materials were studied. The thermodynamic assessment of the interaction of molybdenum with hydroxide and magnesium carbonate in an oxidizing medium is given. The process of thermochemical decomposition of molybdenum was optimized with usage of cheap magnesium-containing minerals to form molybdate and magnesium sulfate. The developed method makes it possible to reduce the cost of thermochemistry, to minimize the release of sulfur dioxide due to its rapid binding to magnesium sulfate.

The goal of this study is to safely reduce dust emissions from ash dumps and create green landscapes at waste storage sites. The most effective way to achieve this is through revegetation, which allows ash dumps to be transformed into green landscapes. Unlike similar studies, this paper examines the revegetation of a sand-covered ash dump under the extreme conditions of a sharply continental climate. The following perennial plant species were selected: Festuca pratensis, Bromus inermis, and Medicago polymorpha. Laboratory studies revealed that Festuca pratensis was the most adapted to the laboratory conditions in an indoor environment, while Medicago polymorpha showed poor development. The maximum height reached by Festuca pratensis was 0.27 m, Bromus inermis reached 0.23 m, and Medicago polymorpha reached 0.10 m. In the field experiments, over three months of vegetation, maximum plant heights were as follows: Festuca pratensis—0.09 m, Bromus inermis—0.11 m, and Medicago polymorpha—0.30 m. Medicago polymorpha exhibited a higher rate of development compared to the grasses. Thus, revegetating ash dumps from thermal power plants presents a promising solution for creating green spaces, aligning with the principles of sustainable urban development.