The method for the mathematical description of phase composition diagrams has been developed. It is based on the balance of distribution of the initial components of the slag or metal over the secondary compounds (phases) formed from them. The equations relating the phase composition to the chemical one are obtained, and a computer program is created on their basis. After setting the chemical composition of the slag from the console and starting it, the computer outputs the phase composition in mass percent, the number of the polytope, its volume, initial and final equations. The method has no restrictions on the number of components considered in the system under study and allows describing five or more component systems that cannot be correctly displayed in three-dimensional space on a plane. Examples of using the model are given. Calculations using the obtained model established that deterioration in the production of carbonaceous ferrochromium from Kazakh ores is due to the movement of slags within the SiO2 – Al2O3 – MgO triple diagram from the region of magnesia spinel (MgO·Al2O3) to the region of predominant forsterite crystallization (2MgO·SiO2) during transition to use of magnesia ores. A predictive estimation of the phase composition of steel-smelting slags with high basicity is given. It was found out that, on average, they contain high-temperature compounds such as periclase (MgO), dicalcium silicate (Ca2SiO4), calcium monoaluminate (CaAl2O4), and magnesia spinel (MgAl2O4) as phase components. All of them are high-temperature compounds, which determine refractoriness of the slag. Presence of Ca2SiO4 in the slag in a large amount (74 %), capable of polymorphic transformation with a volume change by 12 %, can cause decomposition of slags with formation of dispersed dust, which is hazardous to the environment. The calculation results are confirmed by X-ray phase analysis of the slag. The proposed mathematical model also allows solving inverse problems, i.e. to find the composition of the charge to obtain a product with the desired phase composition. It is recommended to load charge containing 68.48 % CaO, 25.10 % SiO2 and 6.43 % Al2O3 into the kiln to obtain high quality white Portland cement clinker with the following composition: 45 % of 3CaO·SiO2, 38 % of 2CaO·SiO2 and 17 % of 3CaO·Al2O3. The work was carried out within the framework of program-targeted funding of the Scientific and Technical Proceedings Program “Creation of new composite materials with high performance properties based on rare and rare earth elements” of the Industrial Development Committee of the Ministry of Industry and Infrastructure Development of the Republic of Kazakhstan.

The diagram of the phase composition of the Fe – Si – Al system and its isothermal sections within the temperature range of 300-3000 K are plotted. Thermodynamic data of Fe3Si, Fe2Si, Fe5Si3, FeSi, FeSi2 silicides, FeAl, FeAl2, FeAl3, Fe2Al5 aluminides and Al2Fe2Si, Al3FeSi, Al2FeSi, Al11Fe3Si6, Al14Fe3Si3 ternary compounds are used. The diagram consists of 20 elementary triangles of coexisting phases, the number of which decreases to 6 at the temperature 1900 K and more. At the temperatures above 2900 K, the equilibrium of the condensed phases is disturbed due to the transition of such metal components of the low-melting aluminum corner of the diagram as Al, Al2, Fe, Si and Si2, leading to losses of valuable elements, to the gas phase. Crystallization fields are assessed by calculating the squares of elementary triangles, as well as the prevalence of each compound in the phase space by taking into account its participation in the construction of adjacent triangles. Using our own method, the mathematical model of the diagram was created in the form of equations for dependence of the amount of the formed phase on the chemical composition of examined metal. The computer program was developed based on the established equations. The examples of calculation of the phase composition of two grades of ferrosilicon FeSi65 and FeSi75, which are the most common in metallurgy, as well as two grades of ferrosilicoaluminum FeSi45Al15 and FeSi55Al20 are presented. Correspondence of the calculated and instrumentally found phase composition of the industrial metal has been revealed. Presence of mathematical models makes it possible to accelerate selection of the metal with the required composition and properties from the set of planned for smelting. This research is funded by the Science Committee of the Ministry of Education and Science of the Republic of Kazakhstan (Grant No. AP09259368).

Рассмотрены распространенные способы получения брикетированного топлива; приведен обзор основных угольных месторождений Казахстана, а также представлены результаты экспериментальных исследований по получению бездымных топливных брикетов путем термоокислительного коксования углей с последующим прессованием полукокса. Показано, что большинство казахстанских углей открытой добычи можно рассматривать как качественное и доступное сырье для получения брикетированного бездымного топлива без применения связующих веществ. Преимущество предлагаемого способа заключается в предварительной термообработке угля, что по сравнению с традиционными процессами термической переработки является автотермичным и энергосберегающим. Низкая спекаемость и наличие летучей составляющей в углях, добытых в таких районах, как Куу-Чек, Борлы, Сарыадыр, Экибастуз, Шубарколь, Майкубе, позволяет проводить их полукоксование в аппаратах периодического действия - ретортах. Удаление в процессе термообработки большей части наиболее вредных токсичных соединений обеспечивает экологическую чистоту брикетированного топлива по сравнению с углем в сфере потребления, то есть при сжигании в бытовых топочных устройствах. Получены опытные образцы топливных брикетов с теплотворной способностью не менее 5100 ккал/кг. Зольность брикетов составляет 21-30%. Вследствие меньшего выхода летучих веществ при сгорании брикетов выброса дыма визуально не наблюдается, что позволяет классифицировать этот продукт как экологически безопасное бездымное топливо с высокими потребительскими...

At Abishev Chemical and Metallurgical Institute, highly effective new alloys have been developed on the basis of resource-saving technology. The alloys may be produced from natural and industrial...

When analyzing a number of phase equilibrium diagrams of various types of systems, the regular relationship was found during the formation of phase crystallization fields in the form of a correlation dependence of the osmotic coefficient of a crystallizing component on the ratio of its activity in the liquid and solid phases. The Bjerrum-Guggenheim osmotic coefficient serves as a measure of the deviation of the energy properties of a real system from the ideal one described by the Schroeder-Le Chatelier equation. Mathematical expressions for the liquidus and solidus lines are obtained in the form of semi-empirical dependences on a single analytical basis, which make it possible to calculate the temperature dependence of the composition. Thus, a theoretically substantiated method for the mathematical description of the lines of monovariant phase equilibria has been developed, based on the regularities of the behavior of components in the melt. Mathematical expressions represent the crystallization fields of the phases of the MnO-SiO2 system for the corresponding components and compounds using the Schroeder-Le Chatelier equation and the correlation dependence of the osmotic coefficient Ф', experimental and calculated data of the Bjerrum-Guggenheim osmotic coefficient (Фi) are calculated. The type of variation in the Bjerrum-Guggenheim osmotic coefficient depends on the intermolecular interaction of the components in the melt. If only van der Waals forces of interaction between the components in the melt prevail, then a correlation dependence is observed. When groups from the initial compounds are formed in the melt, or processes of dissociation or, conversely, association occur, the osmotic coefficient is described by a curvilinear dependence. The paper presents mathematical expressions for the fields of crystallization of phases of the MnO-SiO2 system in the form of semi-empirical dependencies. The nature of the change in the Bjerrum-Guggenheim osmotic coefficient of the crystallizing component depending on the ratio of its activity in the liquid and solid phases is shown. This research is funded by the Science Committee of the Ministry of Education and Science of the Republic of Kazakhstan (Grant No. AP09259157).

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