Constructing Isotherms of Oxygen Solubility in the Liquid Metal of the Cu-Na-K-O System

2018 ◽  
Vol 284 ◽  
pp. 568-574
Author(s):  
O.V. Samoilova ◽  
L.A. Makrovets
Keyword(s):  
Liquid Metal ◽  
Phase Equilibria ◽  
Molten Metal ◽  
Thermodynamic Modeling ◽  
Oxygen Solubility ◽  
Quality Changes ◽  
Metal Melt ◽  
Temperature Range ◽  
Component Solubility

The thermodynamic modeling of phase equilibria in the liquid metal of the Cu–Na–O, Cu–K–O and Cu–Na–K–O systems in the temperature range of 1100–1300 °С was done. The calculations were performed using the methodology of constructing a surface of component solubility in the metal melt, which does not only allow us to calculate the isotherms of oxygen solubility in the molten metal, but also to link the changes in the composition of such molten metal with quality changes in the composition of the interaction products. The isotherms of the oxygen solubility in the liquid metal of the Cu–Na–O, Cu–K–O and Cu–Na–K–O systems were constructed.

scholarly journals Thermodynamic modeling of isotherms of oxygen solubility in liquid metal of Fe – Mg – Al – O system

2019 ◽  
Vol 62 (8) ◽  
pp. 639-645 ◽  
Author(s):  
G. G. Mikhailov ◽  
O. V. Samoilova ◽  
L. A. Makrovets ◽  
L. A. Smirnov
Keyword(s):  
Solid Solution ◽  
Liquid Metal ◽  
Liquid Iron ◽  
Thermodynamic Modeling ◽  
Equilibrium Constants ◽  
Oxygen Solubility ◽  
Ionic Solutions ◽  
Temperature Range ◽  
Oxide Melt ◽  
Oxide Phases

Studying the interaction between oxygen and magnesium and aluminum dissolved in liquid iron is an important task in order to choose optimal parameters for refining and casting of steels. Relevance of this research is caused by determining the possibility and conditions for formation of unfavorable refractory particles of magnesium oxideand magnesian spinel in a metal melt. In the course of this research, thermodynamic modeling of phase equilibria implemented in liquid metal of such systems as Fe – Mg – O, Fe – Al – O and Fe – Mg – Al – O within the temperature range of 1550 – 1650 °С was carried out. Calculation was made using the technique of constructing the solubility surfaces for the metal components which connects quantitative changes in composition of a liquid metal with qualitative changes in composition of products obtained as a result of interaction of a metallic melt’s components. The modeling method was based not only on usin­g equilibrium constants of reactions occurring between components of the systems under research in the selected temperature range, but also on taking into account the values of interaction parameters of the first order (according to Wagner) of elements in liquid iron. In order to simulate activities of the oxide melt conjugated with the metallic one, approximation of the theory of subregular ionic solutions was used. To model activities of oxides solid solution, approximation of the theory of regular ionic solutions was used. And the theory of ideal ionic solutions was used for the solid solution of spinels. In the course of the work, isotherms of oxygen’s solubility in liquid metal of systems Fe – Mg – O, Fe – Al – O and Fe – Mg – Al – O have been constructed, and regions of thermodynamic stability of oxide phases conjugated with the metallic melt have been determined. In particular, compositions area of a liquid metal which is going to be in equilibrium with the solid solution of spinels | FeAl 2 O 4 , MgAl 2 O 4 | solid solution has been determined for Fe – Mg – Al – O system. Results obtained in the course of thermodynamic modeling have been compared to experimental data.

THERMODYNAMICS OF THE PROCESSES OF INTERACTION OF LIQUID METAL COMPONENTS IN Fe – Mg – Al – La – O SYSTEM

2018 ◽  
Vol 61 (6) ◽  
pp. 460-465
Author(s):  
G. G. Mikhailov ◽  
L. A. Makrovets ◽  
L. A. Smirnov
Keyword(s):  
Rare Earth ◽  
Liquid Metal ◽  
Rare Earth Elements ◽  
Phase Equilibria ◽  
Thermodynamic Modeling ◽  
Equilibrium Constants ◽  
Rare Earth Metals ◽  
Oxide Systems ◽  
Metal Melts ◽  
Steel Deoxidation

At the present time, rare-earth elements in metallurgy are used in  the form of mischmetal – a rare-earth elements natural mixture (with  atomic numbers from 57 to 71). It contains about 50  wt.  % of cerium.  The remaining elements are mainly lanthanum and niobium. The specific composition is determined by the ore deposit. Inconstant composition of the modifier containing rare-earth metals (REM) can significantly reduce its efficiency. Experimentally, for every branded steels  composition the ratio of various REMs can’t be selected because of the  high costs of obtaining technically pure rare-earth metals. The task of  determining the each rare earth element optimum concentrations and  complex ligature composition can be solved by thermodynamic modeling. In the framework of thermodynamic modeling, the interaction  between magnesium, aluminum and lanthanum with oxygen in liquid  iron is presented. And the thermodynamic model of steel deoxidation  by these active metals composition is considered. On the basis of available literature data on the phase diagrams of the systems MgO – Al2O3 ,  MgO – La2O3 and La2O3 – Al2O3 , the coordinates of the invariant equilibria points in the system MgO – La2O3 – Al2O3 were determined. The  phase diagram of the system MgO – La2O3 – Al2O3 was constructed. It  made possible to establish all phase equilibria realized in the process  of deoxidation of steel with magnesium, lanthanum and aluminum and  to describe these phase equilibria by chemical reactions equations. The  activity of the components in liquid oxide melts was determined using  the theory of subregular ionic solutions, which takes into account the  dependence of the coordination number of cations on the composition  of the oxide melt. The activity of components in metal melts conjugated with oxide systems were determined by Wagner’s theory using the  parameters of the first order interaction. Equilibrium constants values  for the steel deoxidation reactions are installed indirectly by thermodynamic calculations. On the basis of the obtained data the components  solubility surface in the metal melts of Fe – Mg – Al – La – O system  was constructed, which allowed to determine the liquid metal composition regions associated with the corresponding oxide phase.

Thermodynamic Modeling of Isotherms of Oxygen Solubility in Liquid Metal of the Fe–Mg–Al–O System

2019 ◽  
Vol 49 (8) ◽  
pp. 522-527 ◽  
Author(s):  
G. G. Mikhailov ◽  
O. V. Samoilova ◽  
L. A. Makrovets ◽  
L. A. Smirnov
Keyword(s):  
Liquid Metal ◽  
Thermodynamic Modeling ◽  
Oxygen Solubility

Metastable phase equilibria in the lead-tin alloy system: Part II. Thermodynamic modeling

1989 ◽  
Vol 20 (5) ◽  
pp. 795-803 ◽  
Author(s):  
H. J. Fecht ◽  
M. X. Zhang ◽  
Y. A. Chang ◽  
J. H. Perepezko
Keyword(s):  
Phase Equilibria ◽  
Thermodynamic Modeling ◽  
Metastable Phase ◽  
Alloy System ◽  
System Part

Phase equilibria of the La–Ni–Cu ternary system at 673 K: Thermodynamic modeling and experimental validation

Calphad ◽  
2012 ◽  
Vol 36 ◽  
pp. 8-15 ◽  
Author(s):  
Xuehui An ◽  
Qian Li ◽  
Jieyu Zhang ◽  
Shuanglin Chen ◽  
Ying Yang
Keyword(s):  
Ternary System ◽  
Phase Equilibria ◽  
Thermodynamic Modeling ◽  
Experimental Validation

scholarly journals Thermodynamic modeling of phase equilibria in the system Na2O – CaO – Al2O3

2019 ◽  
Vol 57 (2) ◽  
pp. 111-115
Author(s):  
Svetlana E. Pratskova ◽  
◽  
Evgenia S. Nechaeva ◽  
Keyword(s):  
Phase Equilibria ◽  
Optical Fibers ◽  
Thermodynamic Modeling ◽  
Binary Systems ◽  
Liquid Solution ◽  
Exothermic Effect ◽  
Regression Equations ◽  
Melt Mixing ◽  
Energy Parameters ◽  
State Diagrams

The thermodynamic properties of melts of the Na2O – CaO – Al2O3 system are of considerable interest for metallurgy, technology of ceramic materials, optical fibers. State diagrams CaO – Al2O3, Na2O – Al2O3 have been studied by many researchers and do not have the generally accepted version, and the system Na2O – CaO has not been specifically studied. In the work, thermodynamic modeling of the phase equilibria of the Na2O – CaO – Al2O3 system was carried out within the framework of the generalized theory of “regular” ionic solutions. Equations for the activities of the system components are derived. The energy parameters of the model are determined taking into account melting characteristics and experimental data. The state diagrams of binary systems are constructed using the calculated values of the Gibbs energies for the formation of sodium and calcium aluminates from the corresponding oxides. Using the regression equations of the temperature dependences of the energy parameters of binary melts of the Na2O – CaO – Al2O3 system, the molar mixing functions of the liquid solution раствора G_m^M, H_m^M, S_m^M and the excess thermodynamic functions G^E, H^E, S^E were calculated at 1500-1800 oC. Lime-alumina melts are stable at all temperatures, experiencing negative deviations from ideality. The Gibbs excess energy G^E is negative and in absolute value varies from 5 to 90 kJ/mol. With an increase in the concentration of Al2O3 in the melt and temperature, a tendency toward disorder is clearly manifested: the entropy of the melt mixing changes its sign from “minus” to “plus”. Na2O – Al2O3 melts are formed with an exothermic effect and ordering, and are also stable. They experience strong negative deviations (for G^E) from ideality. However, the situation changes at 55 mol. % Al2O3 and 1700-1800 oС melts of the system are unstable.

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