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Ключевые слова: cement

Investigation properties of waste from the chemical and metallurgical industries to assess the possibility of their use in concrete production

https://doi.org/10.58224/2618-7183-2025-8-4-7
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Аннотация
The investigation was conducted on waste from the chemical industry in the form of carbide silt and metallurgical industry in the form of microsilica. For the study, X-ray phase analysis used on a Shimadzu XRD-7000 diffractometer in Cu Kα radiation. Electron microscopic studies were carried out according to GOST R ISO 22309-2015 on a Tescan Vega III SBH electron microscope with an integrated Oxford X-Act energy-dispersive microanalysis system. The Co standard (MAC, reg. no. 9941 Co) and a cassette of standard samples (MAC, reg. no. 11192) were used as samples. Samples were prepared at the Quorum Q150RES spraying station. The amount of raw sludge components was calculated taking into account the preservation of the saturation coefficient and modular characteristics of the cement plant. The calculation of the raw mix consisted in determining the ratios between its components based on the chemical composition of the raw materials and the specified characteristics of the clinker. The possibility is shown and the limits of carbide silt input are determined for use as a lime component of raw sludge in obtaining cement clinker. The possibility of adjusting the lime component of raw sludge by using microsilica is established, which will allow maintaining a balance in silicon content. The identity in the formation of the main clinker phases formed during sludge firing for the pilot sample and the sample made from the enterprise sludge is proven by the X-ray method. Cement of the CEM-II/A22.5N brand was obtained in laboratory conditions, the properties of which correspond to the properties of cement of the industrial enterprise. It is shown that the use of carbide silt and microsilica in the cement industry will allow not only to use them as raw materials, but also to improve the environmental situation in the territory adjacent to these enterprises.
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Influence of carbon black additives and finely ground waste from stone wool production on characteristics of cement systems

https://doi.org/10.58224/2618-7183-2025-8-4-8
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Аннотация
The object of research is cement composites with additives of carbon black and finely ground waste stone wool production. The work aims to design a mix of a cement composite with the additives of carbon black and finely ground waste from stone wool production, which achieves the best strength characteristics. The results show that carbon black is represented on average by particles of 155 microns with inclusions of large agglomerates up to 1-2 mm in size, consisting of almost homogeneous nanoparticles 10-20 nm in size. Carbon black is distinguished by high hydrophobic properties with a true powder density of 900 kg/m3 and a bulk density of 300 kg/m3. The chemical composition of black carbon is 70-80% carbon and 10-15% oxygen, and it also contains impurity compounds of zinc, iron, sulfur, silicon, and other elements. Carbon additives acquire hydrophilic properties in the presence of a plasticizer, and the degree of their influence on hydration becomes less pronounced. The contraction of the binder during the first three hours of hardening is reduced when carbon black is introduced into the cement system in an amount of 8%. A composition with the best strength characteristics was obtained: the content of finely ground waste from stone wool production is 6% by weight of the binder; carbon black content is 4-5%; W/C = 0.2. However, there is difficulty in mixing the mixture at such a low W/C. With a water-cement ratio of 0.3, this problem is solved, and the strength characteristics remain quite high.
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UTILIZATION OF GYPSUM-BEARING WASTES IN MATERIALS OF THE CONSTRUCTION INDUSTRY AND OTHER AREAS

https://doi.org/10.34031/2618-7183-2021-4-1-5-17
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 5-17 стр.
Аннотация
Rational environmental management is one of the priorities of the technological development of the Russian Federation and most countries of the world. Particularly important in this area is the work undertaken with previously generated and accumulated waste, a whole group of which is gypsum-bearing wastes (GBW), which includes by-products of various industries: phosphogypsum, borogypsum, chlorogypsum, ferrogypsum, citrogypsum, vitamin gypsum, etc. GBW features are similar compositions, prevalence, perennial volumes of stored reserves with stable dynamics of annual growth. This determines the relevance of research on the development of a unified methodology for converting GBW of various types into target products particularly for construction purposes, providing maximum energy efficiency and minimal generation of secondary waste. The starting point of the research is the monitoring of approaches developed by the scientific community which are presented in the article. It is shown that researchers are exploring several main areas of GBW conversion: components of Portland cement and clinker; single and multicomponent binders; direct raw materials for the production of building materials; and road construction. The latter two directions have the greatest potential capacity for the consumption of GBW. The general level of research on the issue is not exhaustive, but has the potential to improve on existing methods of processing and application and promote the search for new and more efficient methods.
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