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KEY WORDS:
mineralizer, calcium fluoride, fluorine sublimation, clinker burning, distribution of fluorine ionsABSTRACT:
The article discusses the process of sublimation of fluorinated compounds formed during the burning of a raw mix with the addition of calcium fluoride. The results of the chemical analysis of the burning products of the raw mix without the use of additives and with the introduction of CaF2 in the amount of 1% and 5% fluorine ions are presented. The results of X-ray phase analysis of the clinkers obtained indicate the formation of the main clinker minerals in all samples. Maps of the distribution of fluorine ions in clinker obtained by scanning electron microscopy allowed us to consider the crystallization of clinker and determine the crystallization sites of fluorinated compounds. The temperature range of the fluorine sublima-tion process during clinker burning is considered in detail and determined using a complex thermal analysis combined with a mass spectrometer demonstrating the process of fluorine volatilization from the burning product with simultaneous mass loss. The presence of fluorine ions in the synthesized clinkers was confirmed, including in the form of CaF2, which did not react to the formation of clinker minerals, as well as its sublimation during burning and cooling of the clinker.FOR CITATION:
Novosyolov A.G. High temperature lean clay ceramics modified with wollastonite / Novosyolov A.G., Dreer Yu.I., Novoselova I.N., Levina Yu.A. // Technique and technology of silicates. – 2024. Vol. 31, No1. – Pp. 4 – 13. – EDN
ABSTRACT:
The influence of supramolecular structures on the optical characteristics of polymers is considered. Studies of fluorine-containing acrylic polymers with fluorine-containing electro-optical chromophores in the side chain have shown that they should have a fibrillar supramolecular structure. The preservation of the fibrillar structure determines the technical conditions (temperature range) for the operation of high-speed integrated optical modulators and switches. The polymers considered in the work were divided into three types according to the degree of polarization kp: polymers for which kp1 = 1.39; polymers with kp2 = <1.17>; polymers with kp3 = 1.003. To calculate nonlinear optical characteristics, the Jepsen equation was used. The possibility of calculating the polarizability of a polymer x from experimental values of the dielectric constant εexp is shown. The approach being developed can be used in medicine and biology to analyze the functioning of neurons (tubulin protein) and identify the causes of age-related changes in human memory. The latter is due to plasticization of tubulin and disruption of its fibrillar structure over time at brain temperature.FOR CITATION:
Matveev T.I. Influence of supramolecular structures of polymers on their electro-optical properties / Matveev T.I., Askadskii A.A., Matseevich T.A. // Technique and technology of silicates. – 2023. Vol. – --, No-. – Pp. 14 – 22 – EDN.
KEY WORDS:
cement silicate paint, heat resistance, crack resistance, sodium hydrosilicate, sodium phosphate, microstructure, energy dispersive analysis
ABSTRACT:
This study presents the results of physicochemical methods of analysis of structure and properties of one-component cement-silicate paint modified by the addition of chrysotile nanofibers on the basis of technogenic wastes of Bazhenov chrysotile 7 grade. The main purpose of adding fibers to the paint composition is to increase the heat resistance and crack resistance of the applied coating on the surface of silicate-based artificial stone materials. Using differential-thermal analysis it is shown that chrysotile fibers increase the thermal resistance of cement-silicate paint up to 600ºС, which is predetermined by the temperature of destruction due to dehydration of chrysotile fibers during heating. When analyzing the microstructure of cured paint using energy-dispersion analysis it is shown that due to chemical affinity of fibers with cement-silicate matrix on the interfacial surface of fibers the formation of amorphous and crystalline phases providing reinforcement of cement-silicate matrix is provided, which, being simultaneously the centers of crystallization, provide the creation of a single conglomerate, which increases the crack resistance of coating on the basis of cement-silicate paint. During operation, simultaneous improvement of properties of cement-silicate paint is achieved due to continued hydration of Portland cement minerals, which provides compaction and adhesion of paint to the painted surface. This allows its application in an extensive temperature range without flaking, cracking and release of undesirable gaseous products. IR-spectral showed that the surface of cement-silicate paint additionally undergoes carbonization under the influence of moisture and carbon dioxide in the environment, which increases the water resistance and durability of the coating. Formation of porous structure of cement-silicate paint in the process of hardening provides vapor and mass exchange, preventing the destruction of the coating in the process of operation.
KEY WORDS:
additive technologies, ceramics, HTC, LTCC, multimaterial 3D-printing
ABSTRACT:
In recent years, there has been a trend towards miniaturization of functional ceramic devices while improving their characteristics. At the same time, the process of rapid prototyping becomes much more complicated and the cost increases when using classical production technologies.KEY WORDS:
composite additives, cement deformation, gypsum, tripoli, calcium sulfoaluminate, sulfoaluminate cement, experimental planning, regression equation.
ABSTRACT:
Shrinkage is one of the main problems related to the hardening of concrete and reinforced concrete structures, which varies depending on the type of concrete and its quality. The negative effects of shrinkage can be prevented by using admixtures with ordinary Portland cement, which produce non-shrinking and expansive cement. The author used gypsum as an additive, mixed it with cement clinker, and obtained expanded cement. Additionally, by using activated mineral additives (AMD) with pozzolanic activity, the author obtained a cement stone with a denser structure, low porosity, and high physical properties. From an economic and environmental perspective, the use of AMD in non-shrinking and expanding cement is also beneficial, as it saves clinker in cement production. The influence of additives on the deformation properties of the binder was studied using the experimental design method. The deformation of cement at the ages of 2, 3, 7, 14, and 28 days was determined according to standard methods for researching the deformation characteristics of cement stone. The research results are presented in surface form and represented by a quadratic regression equation. The regression equation describes the influence of active mineral expansion additives on the deformation of cement stone during hardening. The results obtained include a composition with the maximum expansion effect and a composition with maximum shrinkage when using complex additives. These results can be used in the future to predict the deformation properties of the binder.KEY WORDS:
gypsum paste, gypsum stone, nonequilibrium low-temperature plasma (NLTP), plasma modification of gypsum suspension, strength, setting time
ABSTRACT:
One of the main vectors of development in modern construction is the acceleration of the pace of construction production. The use of chemical additives is not always justified from a technical and economic point of view. Processing raw materials in low-temperature non-equilibrium plasma is an environmentally safe, effective method that does not require complex modifications and re-adjustment of technological equipment. Modification of raw materials in NNTP leads to a reduction in setting time, accelerated hardening of inorganic binders, as well as an increase in the performance characteristics of materials and products. In this work the effect of low-temperature plasma on the properties of high quality gypsum is investigated. Gypsum suspensions with gypsum concentration of 3 and 5% were subjected to the treatment, which were introduced into gypsum with mixing water. It has been proven that the use of plasma-modified gypsum suspensions accelerates the setting of gypsum paste by up to 35.5% and increases the flexural strength of gypsum stone to 10.5%, and compression strength to 22%.KEY WORDS:
silicate raw materials, flux, sintering, sodium, depolymerization
ABSTRACT:
Recycling of large-tonnage industrial waste with the production of construction materials is very promising. Taking into account the high content of refractory components, it is reasonable to reduce the energy intensity of synthesis by introducing fluxing additives of melts. In this article the influence of the most active class of melts - sodium-containing compounds - on sintering and melting of ash and slag wastes (ASW) from thermal power plants is considered. High-temperature synthesis of compositions containing ASW and different amounts of sodium-containing fines (Na2CO3, Na2B4O7, NaF, NaOH) was carried out. It is shown that the Na2O content is not a decisive characteristic in the evaluation of fluxing activity. The most active fluxing agent Na2B4O7 is revealed, even small amounts of which provide sharp acceleration of sintering and melting. The tendency of ash and slag waste to "self-foaming" due to oxidation of residual carbon and formation of pores by released gases has been established. Change of propensity to foaming at introduction of various melts and parameters of the obtained porous structure including dark gray foamed areas and sintered areas of brown color have been studied.KEY WORDS:
white cement, titanium dioxide, cement stone microstructure, self-cleaning effect
ABSTRACT:
White Portland cement is successfully used for the construction of architectural structures and decoration of building facades, and also serves as the main component of many dry building mixtures used for interior decoration. In this study, the effect of highly dispersed powder AEROXIDE TiO2 P25 with a specific surface area of 50 m2/g on the composition, structure and properties of hydrated white Portland cement was investigated. Two types of white cements differing in mineralogical composition were used in the work. It is shown that the rate of formation of hydration products, established by X-ray phase analysis, the amount of formed portlandite and the degree of hydration, with the introduction of highly dispersed powder of titanium dioxide increases and reaches 88-90%, which is 3-5% more than in control samples without addition. It was found that the presence of TiO2 in the composition of the set cement influences the microstructure of cement stone: the distribution of crystalline hydrates becomes more uniform, and their size decreases from 10-35 microns to 8-22 microns. The presence of titanium dioxide in the composition of cements gives them the effect of self-cleaning, as a result of which after 4 hours of surface treatment with UV radiation it is cleaned from external contaminant by 67-80%. The optimum amount of titanium dioxide in white cements can be considered as 1 %, which provides comparable strength characteristics with non-supplemented compositions.KEY WORDS:
Chemical element, D.I. Mendeleev's table, upper bound, dyads, linear dependence, max element, nature code, world constants, Universe, non-electronic types of atomsABSTRACT:
The paper presents two modern versions of the periodic system of chemical elements by D.I. Mendeleev. Both variants contain in their structure a zero period in which the electron, proton and neutron are located, that is, this period does not contain chemical elements, but contains these three elementary particles – the constituent parts of any atom. According to the authors, an electron neutrino (electron antineutrino) should be located behind the zero period, and the photon completes the lower layer of the periodic table. From the photon to the universal Planck length, the scale of as yet unknown particles is realized in the range from 10-18 to 10-35m. Another feature of the proposed tables is the arrangement of lanthanides and actinoids in a perpendicular plane to the existing matrix. Moreover, in the second variant, the triad tables can also be located in a perpendicular plane. All quantum numbers corresponding to the proposed two variants of the periodic table are interrelated with fundamental constants of nature, for example, with such as the fine structure constant, the ratio of the mass of a proton to the mass of an electron, Feigenbaum constants, direct F and inverse f numbers of the golden proportion, the number 𝜋, etc. It is shown for the first time that the square of the product of the first and second Feigenbaum constants approximately coincides with the value of the inverse of the fine structure constant and the ratio F/f and with the limiting value of the orbital quantum number l