Phase Equilibria and Phase Diagrams in Oxide Systems

Author(s):  
Ilya Veksler
2020 ◽  
Vol 299 ◽  
pp. 468-474 ◽  
Author(s):  
Gennady G. Mikhailov ◽  
L.A. Makrovets ◽  
O.V. Samoilova

Thermodynamic modeling of phase equilibria in a liquid metal of Fe–La–Ce–O system at 1600 °С, using the technique of constructing the solubility surfaces for the components of a metal, was carried out. The calculation technique allowed assessing the depth of liquid iron de-oxidation at a complex use of lanthanum and cerium as deoxidizing agents. Also, diagrams of de-oxidants’ consumption for one ton of liquid oxygen-containing iron were calculated in the course of the work. Carrying out a calculation of the solubility surfaces for the components of a metal required simulation of phase diagrams of the following oxide systems: FeO–La2O3–Ce2O3, FeO–CeO2–La2O3, CeO2–La2O3–Ce2O3. The obtained results might be of interest for optimization of the use of rare-earth metals in steelmaking technology.


2020 ◽  
Vol 65 (6) ◽  
pp. 3091-3102 ◽  
Author(s):  
Min Zhang ◽  
Peng Wu ◽  
Yaoyao Li ◽  
Wenxuan Li ◽  
Huan Zhou

2014 ◽  
Vol 1015 ◽  
pp. 405-408
Author(s):  
Bai Hui Bu ◽  
Fei Li ◽  
Ya Fei Guo ◽  
Shi Qiang Wang ◽  
Tian Long Deng

It is well known that phase equilibria and phase diagrams can successfully guide the comprehensive utilization of the salt lake resources. The researches on phase chemistry and thermal chemistry of the calcium-containing brine system are essential to promote the development of brines. In this paper, the progresses on the phase chemistry and thermal chemistry of the calcium-containing brine system around the world from 2007 up to now were summarized. The problems existed and the new trends in the future were also carried out.


2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Panpan Li ◽  
Kaiyu Zhao ◽  
Shangqing Chen ◽  
Jiayin Hu ◽  
Yafei Guo ◽  
...  

Phase equilibria and phase diagrams for the ternary aqueous system containing lithium, sodium, and pentaborate ions at 298.15 and 323.15 K and 101.325 kPa were investigated by the methods of isothermal dissolution equilibrium. From the experimental data, the phase diagrams and the diagrams of physicochemical properties versus composition of lithium pentaborate in the equilibrium systems were plotted, respectively. The phase diagrams of the ternary system LiB5O8 + NaB5O8 + H2O at two temperatures contain one invariant point, two univariant curves, and two crystallization regions corresponding to sodium pentaborate pentahydrate (NaB5O8·5H2O) and lithium pentaborate pentahydrate (LiB5O8·5H2O). Due to the different dissolution behaviors of pentaborate salts in the aqueous systems, the component of LiB5O8 has a relatively strong effect on the solubility of NaB5O8. It was found that this system belongs to a simple eutectic type at two temperatures, and neither double salts nor solid solutions were formed. The densities and refractive indices in the ternary system at 298.15 and 323.15 K are as similar as changing regularly with the increase of LiB5O8 concentration. On the basis of empirical equations of the density and refractive index in electrolytes, the calculated values of density and refractive index agreed well with the experimental values at two temperatures.


2007 ◽  
Vol 71 (8) ◽  
pp. 1183-1186 ◽  
Author(s):  
L. B. Vedmid’ ◽  
V. F. Balakirev ◽  
A. M. Yankin ◽  
Yu. V. Golikov

2018 ◽  
Vol 61 (6) ◽  
pp. 460-465
Author(s):  
G. G. Mikhailov ◽  
L. A. Makrovets ◽  
L. A. Smirnov

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.


2014 ◽  
Vol 1015 ◽  
pp. 401-404
Author(s):  
Long Li ◽  
Dao Lin Gao ◽  
Jiang Ping Zeng ◽  
Ya Fei Guo ◽  
Tian Long Deng

Salt lake brine resource is one of the strategic resources in the western of China. Phase equilibria and phase diagrams are the theoretic foundation for the exploitation of salt lake brine resources. Hence, studies for the stable and metastable phase equilibria of lithium-containing salt-water systems are of the great importance for the development of salt lake brine resources. In this paper, the stable and metastable phase equilibria of lithium-containing salt-water systems were summarized, and the problems existed at present and the new trends in the future are also discussed.


Sign in / Sign up

Export Citation Format

Share Document