A growing demand for products made of jewelry and ornamental stones, including nephrite, requires an increase in mining volume. However, only less than 30% of the extracted raw material is suitable for processing. The rest of the low grade nephrites are substandard and unclaimed, and they negatively affect various life spheres. In this regard, their involvement in industrial turnover is an actual task. One of the directions of mining waste use is production of building materials, in particular, cements. The low grade nephrite can act here as mineral additives. In the course of the research, the optimal amount of low grade nephrite waste additive was determined, which is 30% of the cement mass. The grinding time of a raw mix is 10 min. It was found that introduction of the additive affects the hydration activity of cement compositions. Compressive strength of the mixed cement is 25% higher than that of the control sample. At the same time, new phases in the hydrated cement were not recorded. Good physical and mechanical properties of the obtained cements are achieved when hardening in normal humidity conditions. Heat and humidity treatments do not facilitate the hydration processes in binary systems. The conducted studies have shown that low grade nephrite can be used as mineral additives in cement production. This will allow development of not only a new type of product, but also reduction of the negative impact of cement production on the environment.

At present, there is a shortage of high-quality feedstock to produce widely used building materials—concretes. Depletion of natural resources and growing restrictions on their extraction, in connection with environmental protection, necessitate the search for an equivalent replacement for conventional raw materials. Magnesium–silicate rocks are a waste of the mining industry. We researched the possibility of using these rocks as coarse and fine aggregates in heavy concrete production. Following the requirements of the national standards, we studied the physical and mechanical characteristics of the obtained material. It was found that the strength of concrete, made of magnesium–silicate rock coarse aggregate, at the age of 28 days of hardening is within 28 MPa, while the strength of the control sample is 27.3 MPa. Replacing quartz sand with dunite sand also leads to an increase in concrete strength (~4%). Complete replacement of aggregates facilitates an increase in strength by 15–20% than the control sample. At the same time, the density of the obtained materials becomes higher. Concretes have a dense structure that affects their quality. Concrete water absorption is within 6%. The fluxing coefficient is 0.85–0.87. The application of magnesium–silicate rocks in concrete production enables the complete replacement of conventional aggregates with mining waste without reducing the quality of the obtained materials. Furthermore, the issues of environmental protection in mineral deposit development are being addressed.

Relevance. The need to dispose ash and slag waste from CHPP-1 and CHPP-2 in Ulan-Ude, which have a negative impact on the environment. A promising way to eliminate environmental damage is the biological reclamation of ash dumps. Its result is manifested in greening dumps and reducing ash deflation. Aim. To study ash and slag wastes from thermal power plants in Ulan-Ude and establish the possibility of reclamation of ash dumps to reduce the negative impact on the environment. Objects. Ash and slag wastes from the ash dumps of CHPP-1 (ASW-1) and CHPP-2 (ASW-2) in Ulan-Ude. Methods. Chemical, X-ray phase, granulometric, microscopic methods of analysis. Results. The authors have determined chemical, mineralogical and grain compositions of ash and slag wastes from thermal power plants. It was established that they have a high content of silicon, aluminum and a low content of calcium and magnesium. Ash and slag contain vitreous, crystalline and organic components. In the waste, to a greater extent, there is a crystalline phase containing silica, mullite, hematite, magnetite and, to a lesser extent, a glass phase, represented mainly by minerals of the orthoclase group. In terms of granulometric composition, the waste from CHPP-1 is dominated by a finer fraction compared to CHPP-2. Laboratory studies of soil mixtures based on ash and slag waste and local ameliorants (sewage sludge, lignin and chicken manure) were carried out. The optimal ratio of soil components was determined, equal to 4:1:1:1. A beneficial effect of sewage sludge was revealed, as well as a negative effect of high doses of bird droppings on growth and development of plants. Pure ash and slag from CHPP-1 and CHPP-2 without introduction of ameliorants can act as an independent substrate for perennial grasses. Актуальность исследования обусловлена необходимостью утилизации золошлаковых отходов ТЭЦ-1 и ТЭЦ-2 г. Улан-Удэ, которые негативно воздействуют на окружающую среду. Перспективным способом устранения экологического вреда является биологическая рекультивация золоотвалов, результат которой проявляется в озеленении отвалов и снижении дефляции золы. Цель: изучить золошлаковые отходы теплоэлектроцентралей г. Улан-Удэ и установить возможность рекультивации золоотвалов для снижения негативного воздействия на окружающую среду. Объекты: золошлаковые отходы из золоотвалов ТЭЦ-1 (ЗШО-1) и ТЭЦ-2 (ЗШО-2) г. Улан-Удэ. Методы: химический, рентгенофазовый, гранулометрический, микроскопический методы анализа. Результаты. Определен химический, минералогический и зерновой составы золошлаковых отходов теплоэлектроцентралей. Установлено, что они имеют высокое содержание кремния, алюминия и низкое – кальция, магния. Отмечено, что золошлаки содержат стекловидные, кристаллические и органические составляющие. В отходах в большей степени присутствует кристаллическая фаза, содержащая кремнезем, муллит, гематит, магнетит и в меньшей – стеклофаза, представленная в основном минералами группы ортоклаза. По гранулометрическому составу в отходах ТЭЦ-1 преобладает более мелкая фракция по сравнению с ТЭЦ-2. Проведены лабораторные исследования почвенных смесей на основе золошлаковых отходов и местных мелиорантов (осадки сточных вод, лигнин и куриный помет). Определено оптимальное соотношение компонентов почвогрунта, равное 4:1:1:1. Выявлено благоприятное воздействие осадков сточных вод, а также негативное влияние высоких доз птичьего помета на рост и развитие растений. Отмечено, что чистые золошлаки ТЭЦ-1 и ТЭЦ-2 без внесения мелиорантов могут выступать в качестве самостоятельного субстрата для многолетних трав.

The Kavokta deposit in Russia contains gray and black dolomite-type nephrite, which is in high demand commercially. Although the fact that black nephrite has been found in several deposits, the reasons for its color are not well understood. The present study aims to identify the localization and mineral composition of gray and black nephrite, and to determine the reasons for its dark coloration. The mineral composition of nephrite was studied using a scanning electron microscope with energy-dispersive microanalysis (SEM-EDX) and X-ray phase analysis. Also, the isotopic composition of carbon in graphite in nephrite and in carbonates associated with nephrite in the surrounding strata was determined. The gray–black color in most samples from the southeastern part of the Kavokta deposit (lodes 17 and 28 of the nephrite-bearing zone 4 of the Medvezhy section and lode 6-1 of the nephrite-bearing zone 6 of the Levoberezhny section) is due to the presence of graphite. Syngenetic graphite formed both by the organic matter buried in dolomites and by the decomposition of carbon dioxide that is released during decarbonation under the influence of deep-seated hydrogen. The color of nephrite also depends on the iron content, changing from white to light green as the iron content increases. The gray color of tremolite–diopside nephrite is due to the development of chlorite aggregates that replace diopside and/or tremolite. The gray-green to black color of the nephrite in the northwestern part of the Kavokta deposit (lode 1 of the nephrite-bearing zone 1 of the Prozrachny section) is due to the high iron content in the tremolite–actinolite at the contact with the epidote–tremolite skarn formed after amphibolite. The identified patterns of black nephrite localization can be used in the process of geological exploration of similar deposits elsewhere in Russia and abroad.

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.

An important role in the study and the obtaining of new phases with valuable physical and chemical properties is taken by ternary compounds with a tetrahedral anion containing various combinations of mono- and multivalent cations, including ternary molybdates and tungstates. Silver ternary molybdates AgA3R(MoO4)5 with the NaMg3In(MoO4)5 structural type (triclinic crystal system, space group P1, Z = 2) are of particular interest and have a high ion conductivity (10–3–10–2 S/cm). In this regard, the aim of this work was to reveal the possibility to form similar compounds in silver, zinc, indium, and iron molybdate and tungstate systems and to determine the effect of the nature of tetrahedral anion and three-charged cations on their obtaining and properties. Polycrystalline samples were synthesized using a ceramic technology and studied by differential thermal (DTA) and X-ray diffraction analysis (XRD). 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