Thermodynamic modeling of phase composition for Fe-Ca-Si-Al system

In this paper, theoretical studies on the construction of phase structure diagrams of the Fe-Ca-Si-Al system as modeling composition of alloy by Thermodynamic-diagram analysis (TDA) were carried out. TDA analysis allows predicting the optimal composition of alloys using phase structure diagrams of the multicomponent systems. TDA excludes complex mathematical apparatus. Also, TDA allows to obtaine data for the Fe-Ca-Si-Al system, a diagram of phase relationships, each elementary subsystem of which is independent. By analyzing the binary systems, the state diagram of Fe-Ca-Si-Al metal system was constructed, which simulates the final phase composition of the ferroalloy. The reliability of the effectiveness of these methods is confirmed by large-scale laboratory melting tests

Development of Smelting Technology of Complex Ferroalloy with the Use of High-ash Coals

The article presents the results of studies that contribute to solving the problem of extraction of aluminum from the ash part of high-ash coals and its further application in ferrous metallurgy. Technologies of obtaining multicomponent complex alloys, including ferrosilicon aluminum, aluminosilicate manganese, and aluminum-silicon-chrome were described in detail. These complex alloys are designed for deoxidation and partial alloying of steel, as well as for the metal-thermal production of various ferroalloys. The main charge material for their production is high-ash coals, which are not used in the national economy and belong to man-made waste. The content of solid carbon in high-ash coals is sufficient for the passage of all reduction reactions, which eliminates the use of expensive coke from the process chain. The use of cheap materials and the refusal to use metallurgical coke allows smelting complex alloys at a relatively low cost. The article also presents the results of a series of large-scale laboratory and pilot tests on the smelting of the above complex alloys using high-ash coals from various coal basins of Kazakhstan. A detailed analysis was made to identify the advantages and disadvantages of the developed technologies in comparison with their analogues. Keywords: complex alloy, high-ash coal, ferrosilicon aluminum, aluminum-siliconchrome, aluminum-silicon-manganese, slag-free proces

Thermodynamic modeling of phase composition for Fe-Ca-Si-Al system

In this paper, theoretical studies on the construction of phase structure diagrams of the Fe-Ca-Si-Al system as modeling composition of alloy by Thermodynamic-diagram analysis (TDA) were carried out. TDA analysis allows predicting the optimal composition of alloys using phase structure diagrams of the multicomponent systems. TDA excludes complex mathematical apparatus. Also, TDA allows to obtaine data for the Fe-Ca-Si-Al system, a diagram of phase relationships, each elementary subsystem of which is independent. By analyzing the binary systems, the state diagram of Fe-Ca-Si-Al metal system was constructed, which simulates the final phase composition of the ferroalloy. The reliability of the effectiveness of these methods is confirmed by large-scale laboratory melting tests

Thermodynamic diagram analysis (TDA) of MnO–CaO-Аl2O3-SiO2 and phase composition of slag in refined ferromanganese production

The research presents the calculations of the analytical expressions of the oxide system MnO-CaO-Al2O3-SiO2 and the phase compositions of the slags from the production of refined ferromanganese. It is determined that the system under consideration is divided into 19 elementary quasi-systems consisting of incongruently melting and congruently melting compounds. The sum of the relative volumes of the elementary tetrahedron of the MnO-CaOAl2O3-SiO2 system equals one (1,000000), which confirms the accuracy of the performed calculations. Quasi-volumes in the system MnO-CaO-Al2O3-SiO2, simulating the composition of the resulting slag in the process of metallothermic recovery of manganese concentrates are found

Research of electrical resistance and beginning softening temperature of high-ash coals for melting of complex alloy

The research results are demonstrated on the electrical resistance and beginning softening temperature of the highash coals of Saryadyr, Borly and Zhamantuz deposits (Republic of Kazakhstan). Such parameters of the charge in the ore-thermal furnace provide a low fraction of the charge conductivity, and thereby contribute to the release of a main energy fraction in a reaction zone of the furnace where a metal is formed. The research results showed that a value of the electrical resistance of the charge at the non-isothermal heating to the high temperatures depends on the chemical and mineralogical composition of the charges, and on processes of phase transformations in a sample

Application of the Aluminosilicon Manganese to Obtain Refined Grades of Ferromanganese

This work is dedicated to improving the smelting technology for refined ferromanganese grades through the use of a special complex reducing agent. Laboratory scale experiments were carried out on the smelting of refined ferromanganese using a briquetted charge. Fine fractions (0–5mm) were used for briquetting manganese ore and alumosilicomanganese alloy (AlSiMn). During the experiment were used laboratory installation “HYDROPRESS 50” and coreless induction furnace IUP-25. At the temperature of 1350∘C, the beginning of the charge melting was noted, and at the temperature of 1450∘C, the formation of a liquid melt. According to the chemical analysis, metal samples fully comply with the requirements of the standard. The progress of process parameters has been achieved: the rate of manganese extraction from ore is 70% (according to the traditional technology, it is 55%); slag/metal ratio is 1.8–2.0 (according to the traditional technology, it is 2.2–2.5); known values of slag basicity are 1.5–1.6. Laboratory melting slags were obtained in a stony state with no signs of breaking. As the outcome of this work, a high efficiency of using the reducing agents based on silicon and aluminum in refined ferromanganese smelting, as well as the use of primary manganese ores from Ushkatyn III deposit for smelting refined ferromanganese, allow reducing the lime consumption up to 40% due to the high content of calcium oxide in ore. Keywords: refined ferromanganese, alumosilicomanganese alloy, manganese ore, briquette, sla

Melting of ferrosilicon manganese with the use of high ash rock coal as a reducing agent

A study of the process of smelting ferrosilicon manganese with the use of high ash rock coals as a reducer instead of traditional coke was carried out. The physicochemical properties of coke from high-ash coals of the Kuu-chek deposit have been studied. The fundamental possibility of its application for the production of standard ferrosilicon manganese in large-scale laboratory conditions has been shown

Assessment of dissociation rate of FeCr2O4 using the Bjerrum-Guggenheim coefficient

A calculation procedure of line positions of the monovariant phase equilibrium for the crystallization regions of a congruent compound using the osmotic coefficient of Bjerrum-Guggenheim (ɸ’ Am Bn) was developed. The relevant mathematical apparatus for an analytical description of lines and surfaces of the phase crystallization was recommended. As an example of FeO-Cr2O3 oxide system, the assessment of dissociation rate of congruent compound of FeCr2O4 was performed. The demonstration material of behavior of the osmotic coefficient of Bjerrum-Guggenheim under boundary conditions as assessment criterion of melt structurewas presented

Thermodynamic-diagram analysis of the Fe-Si-Al-Mn system with the construction of diagrams of phase relations

In the practice of complex theoretical studies of multicomponent systems, the so-called thermodynamic-diagram analysis method is known, which greatly simplifies the study of the features of phase transformations in multicomponent systems by dividing them into thermodynamically stable elementary partial subsystems of the same dimension as the main one. Thermodynamic-diagram analysis combines a thermodynamic assessment of the chemical interaction of components in the system under study with a geometric diagram. Such a combination, as studies of the physico-chemical bases of the production of refractories and ferroalloys have shown, turns out to be productive when interpreting chemical interactions in complex systems