Abstract—Under increasing requirements for the properties of steels, one of the ways to produce a high-quality product is microalloying with rare earth elements such as cerium, which can significantly influence the mechanical properties of steel even at low concentrations. To reduce the cost of steel, it is rational to introduce it into steel by direct reduction from oxide systems rather than by adding ferroalloys. To study this process, thermodynamic modeling of cerium reduction by aluminum and calcium carbide from slags of the CaO–SiO2–Ce2O3 system containing 15

The influence of the cerium oxide content and the basicity of slag on the viscosity and the temperature of the beginning of solidification of the CaO–SiO2–Ce2O3 system containing 15

The authors studied the physical properties of the slags of CaO ‒ SiO2 ‒ Al2O3 ‒ MgO system containing cerium oxide. The developed slags are based on a calcium silicate system, the basicity (CaO)/(SiO2) of which has a great influence on the slag properties. Generalization of the performed studies results allowed obtaining new data on the effect of basicity in cerium-containing slags of the studied oxide system on viscosity, temperature of crystallization onset and structure. Experimental studies of the physical properties of cerium-containing slags showed that with an increase in basicity of 2.0 ‒ 5.0, an increase in temperature of crystallization onset and viscosity is observed associated with structure of the formed slags. An increase in basicity from 2.0 to 5.0 contributes to an increase in viscosity from 0.20 to 0.41 Pa·s at 1500 °C and an increase in the crystallization temperature from 1397 to 1497 °C. The structural analysis showed that the structure of the cerium-containing slag is influenced by both the Si4+ ion and the Al3+ ion, which are grid-forming agents. Silicon ions in this system are present in the form of [SiO4 ]-tetrahedra, whereas aluminum ions are present in form of [AlO4]-tetrahedra and [AlO6]-octahedra. With an increase in basicity 2.0 to 2.5, the silicon structure becomes more complicated, and then at a basicity of 3.5 ‒ 5.0 it becomes simpler, whereas the aluminate one becomes more complicated due to an increase in the content of CaO, which participates in charge compensation of polymerized structural units [AlO4 ]-tetrahedra with the formation of a more stable tetrahedral structure, and as a result of increased slag viscosity. Slags of the studied oxide system containing 15 % Ce2O3 are characterized by a sufficiently high liquid mobility in the considered basicity range.

One of the ways to obtain high-quality products and meet ever-increasing requirements on properties of steel is microalloying it with rare earth elements such as cerium. Cerium can significantly affect mechanical properties of steel even at low concentrations. To reduce the cost of steel, it is rational to add cerium into steel not with ferroalloys but by direct reduction from oxide systems. In order to study this process, thermodynamic modeling of the reduction of cerium from slags of the CaO–SiO₂–Ce₂O₃ system, containing 15% Al₂O₃ and 8% MgO, with aluminum and calcium carbide at temperatures of 1 550 and 1 650°C is carried out. The simulation is performed using the HSC 6.12 Chemistry software package (Outokumpu) based on Gibbs energy minimization and using the simplex planning lattice method. The results of thermodynamic modeling are presented in the form of composition-property (equilibrium cerium content in the metal) diagrams for temperatures of 1 550 and 1 650°С. When using metallic aluminum as a reducing agent, increasing the basicity of the slag (CaO/SiO₂) from 2 to 5 at a temperature of 1 550°C leads to an increase in the equilibrium cerium content in the metal from 2 to 20 ppm in the concentration range of 0–15٪ Ce₂O₃, i.e. an increase in the basicity of the slag is beneficial for the development of the cerium reduction process. An metal temperature increase also has a positive effect on the process of reduction of cerium with aluminum. With an increase in temperature to 1 650°С, the equilibrium content of cerium in the metal increases from 4 ppm to 30 ppm in the concentration range of 0–15٪ Ce₂O₃. The use of calcium carbide as a reducing agent leads to an increase in the concentration of cerium in the metal to 30 and 40 ppm at temperatures of 1 550 and 1 650°C, respectively, at a basicity of 5. The decisive role of slag basicity, cerium oxide concentration and temperature in the development of the process of cerium reduction with aluminum and calcium carbide is confirmed.

The effect of cerium oxide on the viscosity and crystallization temperature of slags of the CaO-SiO2-Ce2O3-Al2O3-MgO oxide system is studied using an electrovibrational viscometer. The structural characteristics of hardened slag samples are studied using a Raman microscope-spectrometer. The results demonstrate that the viscosity and crystallization temperature of the slags are considerably reduced upon adding cerium oxide. An increase in content of Ce2O3 from 0% to 15% facilitates decrease in slag viscosity from 0.4 to 0.2 Pa center dot s at 1500 degrees C and reduction in crystallization temperature from 1485 degrees C to 1397 degrees C. The structural analysis results reveal that the main form of polymerization of the [SiO4]-tetrahedra in the silicate regions are the structural units QSi0\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${Q}_{\mathrm{Si}}<^>{0}$$\end{document}, QSi1\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${Q}_{\mathrm{Si}}<^>{1}$$\end{document}, and QSi2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${Q}_{\mathrm{Si}}<^>{2}$$\end{document} for the slags with 0%, 5%, and 10% Ce2O3, respectively, except for the slag with 15% Ce2O3, for which we noted only 2 units QSi0\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${Q}_{\mathrm{Si}}<^>{0}$$\end{document} and QSi1\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${Q}_{\mathrm{Si}}<^>{1}$$\end{document}, which shows structural simplification. A second characteristic peak appears with increase in content of cerium oxide, corresponding to the [AlO6]-octahedral unit, which also indicates structure simplification. The degree of melt polymerization decreases from 0.83 to 0.52 with increase in content of cerium oxide, which explains the decrease in viscosity and crystallization temperature. Cerium oxide is used as a structure modifier to reduce the slag viscosity.

The authors studied the physical properties of the slags of CaO ‒ SiO 2 ‒ Al 2 O 3 ‒ MgO system containing cerium oxide. The developed slags are based on a calcium silicate system, the basicity (CaO)/(SiO 2 ) of which has a great influence on the slag properties. Generalization of the performed studies results allowed obtaining new data on the effect of basicity in cerium-containing slags of the studied oxide system on viscosity, temperature of crystallization onset and structure. Experimental studies of the physical properties of cerium-containing slags showed that with an increase in basicity of 2.0 ‒ 5.0, an increase in temperature of crystallization onset and viscosity is observed associated with structure of the formed slags. An increase in basicity from 2.0 to 5.0 contributes to an increase in viscosity from 0.20 to 0.41 Pa·s at 1500 °C and an increase in the crystallization temperature from 1397 to 1497 °C. The structural analysis showed that the structure of the cerium-containing slag is influenced by both the Si 4+ ion and the Al 3+ ion, which are grid-forming agents. Silicon ions in this system are present in the form of [SiO 4 ]-tetrahedra, whereas aluminum ions are present in form of [AlO 4 ]-tetrahedra and [AlO 6 ]-octahedra. With an increase in basicity 2.0 to 2.5, the silicon structure becomes more complicated, and then at a basicity of 3.5 ‒ 5.0 it becomes simpler, whereas the aluminate one becomes more complicated due to an increase in the content of CaO, which participates in charge compensation of polymerized structural units [AlO 4 ]-tetrahedra with the formation of a more stable tetrahedral structure, and as a result of increased slag viscosity. Slags of the studied oxide system containing 15 % Ce 2 O 3 are characterized by a sufficiently high liquid mobility in the considered basicity range.

The rapid growth of demand for stainless steel and, accordingly, its production, which occurred in the second half of the 20th century and continues till today, makes it necessary to conduct studies of the properties of oxide systems that will contribute to the improvement of metallurgical production technologies for such steel. Therefore, in this paper, using the method of simplex grids for experimental planning and vibration viscometry, a study was conducted of the effect of basicity and boron oxide content on the viscosity and crystallization onset temperature of slags of the СаО–SiO2–B2O3–12%Cr2O3–3%Аl2O3–8%МgO oxide system formed during the reduction period of the production of low-carbon stainless steel by the argon-oxygen decarbonization (AOD) process, which is currently the main method for producing corrosion-resistant steel. The introduction of boron oxide into AOD-slags is a possible solution to the problem of instability of the physical properties of slags during smelting, caused by the volatility of fluorspar fluorides, traditionally used as a flux, and compliance with increasingly stringent environmental requirements by eliminating the formation of toxic fluorine compounds. Based on the results of experimental studies of the viscosity of slags of the studied oxide system depending on the chemical composition and temperature, approximating mathematical models in the form of a reduced third-degree polynomial are constructed. Graphically, the results of mathematical modeling are presented in the form of “composition – property” diagrams, which allow quantitatively determining the effect of temperature and chemical composition of the slags under study on viscosity and their composition on the crystallization onset temperature. It is noted that at 1600 and 1650°C, an increase in the boron oxide content in the slag from 3.0 to 6.0% has a favorable effect on the fluidity of the formed slags in the basicity range of 1.0-2.5. For example, an increase in the boron oxide concentration from 3.0 to 6.0% ensures a decrease in the viscosity of the slags from 2.0 to 0.5 Pa s at a temperature of 1600°C and from 0.4 to 0.3 Pa s at a temperature of 1650°C in the region of increased basicity up to 2.0-2.5.

Using the method of simplex lattices for experiment planning, the viscosity of slags of the CaO-SiO2-Cr2O3-3%Al2O3-8%MgO-6%B2O3 system was studied in a wide range of chemical composition. For each viscosity value, adequate mathematical models are obtained in the form of a reduced III degree polynomial. The results of mathematical modeling are presented graphically in the form of composition-viscosity diagrams. The range of compositions of the studied slags with a basicity of 1.5-2.0 has a high liquid mobility in the temperature range of 1600 -1700°C and their viscosity does not exceed 0.3 Pa·s.

Using the simplex lattice method of experiment planning lattices, the physicochemical properties of slags of the СаО–SiO2–B2O3–2 % Cr2O3–3 % Аl2O3–8 % МgO oxide system are studied in a wide range of chemical composition (CaO/SiO2 = 1.0–2.5; 0–6 % B2O3), i. e. viscosity, crystallization onset temperature, equilibrium distribution of sulfur between slag and metal. Mathematical models of slag properties dependence on its composition are constructed in the form of a reduced polynomial of the third degree. The results of mathematical modeling of the sulfur removal reaction and experimental studies of the viscosity of slags and their crystallization onset temperatures are presented graphically in the form of “composition–property” diagrams. It’s found that the addition of up to 6% boron oxide significantly liquefies slags and reduces the temperature of the onset of crystallization, while maintaining the possibility of deep desulphurization of the metal. For effective metal processing, the composition range of slags with a basicity of 2.0–2.5 and a content of 4.0–6.0 % boron oxide is optimal. These slags have high liquid mobility (viscosity of the formed slags does not exceed 0.3 Pa•s) and provide the sulfur content in the metal not more than 0.003–0.004 %. The slags of this area are homogeneous, since their crystallization onset temperature doesn’t exceed 1500 °C. Experimental studies of metal desulfurization under the basic slags of the studied local simplex confirmed the data characterizing the influence of the boron oxide content and the basicity of the formed slags on their viscosity and its role in the efficiency of the desulfurization process.

The effect of basicity on the phase composition, structure, viscosity and crystallization temperature of CaO–SiO2–Al2O3–MgO–B2O3 fluorine-free slags was studied using vibrational viscometry and thermodynamic phase composition modeling in combination with Raman spectroscopy. The viscosity of the studied slags was established to depend mainly on the phase composition. Despite the complex reticular structure, consisting mainly of [SiO4] and [BO4] structural units with a large quantity of bridging oxygen, long slags (having a wide temperature range of viscosity variations) with low basicity possess high flowability in a liquid state as well as a low temperature of crystallization. This can be explained by the fact that the introduction of boron oxide is accompanied by the formation of a significant quantity of low-melting phases (CaO–B2O3, 2CaO–B2O3, and CaO–MgO–2SiO2) in the slag, which reduces the slag crystallization temperature, as well as increases its overheating and decreases viscosity. At an increase in basicity, long slags smoothly transform into short ones (with a narrow temperature range of viscosity variations); moreover, their structure is simplified along with an increase in the quantity of high-melting phases. In this case, despite the structural simplification, the slag crystallization temperature increases, which leads to the reduction in the degree of overheating and an increase in the viscosity.

Influence of basicity on viscosity, crystallization onset temperature, phase composition, and structure of slags of the СаО – SiO2 – 18 % Cr2O3 – 6 % B2O3 – 3 % Аl2O3 – 8 % МgO system in the basicity range (B = CaO/SiO2 ) from 1.0 up to 2.5 was studied using vibrational viscometry, thermodynamic modeling, and Raman spectroscopy. It was established that the physical properties of slags depend on the balance of polymerization degree and phase composition. Acid slags with a basicity of 1.0 belong to the category of “long” slags and are characterized by an increased proportion of high-temperature phases up to 34.1 %. However, despite the fact that the proportion of high-temperature phases is 1.6 times higher compared to the proportion of low-temperature ones, they are characterized by a simpler silicate structure, providing a viscosity of no more than 0.25 Pa·s at a crystallization onset temperature of 1530 °C. An increase in basicity of slags of the studied oxide system (up to 2.5), along with an increase in the proportion of high-temperature phases (by almost 5.9 times), is accompanied by formation of a more complex silicate structure. The resulting four-coordination structural elements [CrO4] and [AlO4] are embedded in the silicate structure and complicate it, which increases the polymerization degree. Thus, at basicity of 2.5, due to a high proportion of high-temperature phases in the slag and development of polymerization process, slag crystallization onset temperature increases to 1700 °C and its viscosity reaches 1.0 Pa·s at a temperature of 1670 °C.

The study of the influence of the content of cerium oxide and the basicity of the slag on the viscosity and temperature of the onset of crystallization of the CaO–SiO2–Ce2O3 system containing 15% Al2O3 and 8% MgO was carried out using the simplex-lattice method of experiment planning, which makes it possible to obtain mathematical models describing the dependence of the property on the composition as a continuous function. Using the experimental data, we built mathematical models that describe the relationship between the temperature of a given viscosity and the composition of the oxide system. Then, by combining the obtained composition-temperature diagrams of a given viscosity on the isothermal section of the composition-viscosity diagram, a set of viscosity isolines was obtained. Generalization of the results of mathematical modeling and graphical display on the isothermal section of the composition-viscosity diagram made it possible to obtain new data on the viscosity of the CaO–SiO2–Ce2O3 oxide system containing 15% Al2O3 and 8% MgO, in the range of basicity 2–5 and the content of 0–15% Ce2O3. Experimental data show that the slags of the studied oxide system, which do not contain cerium oxide, are characterized by an increased crystallization temperature and viscosity in the studied range of basicity. The presence of cerium oxide in the slags of the studied oxide system provides a rather low viscosity and crystallization start temperature in the temperature range of 1500–1550°C. An increase in the content of cerium oxide in slags with a basicity of 2–3 from 1 to 15% is accompanied by a decrease in the crystallization onset temperature from 1490 to 1410°C. Increasing the basicity to 5.0 leads to an increase in the temperature of the onset of crystallization to 1520°C. At a temperature of 1500°C, the viscosity of slags with a basicity of 2.0–3.0, containing 7–15% Ce2O3, varies within 0.2–0.3 Pa · s. An increase in slag basicity to 3.0–5.0 at a fixed Ce2O3 content of 7–15% is accompanied by an increase in slag viscosity up to 1.0 Pa · s and reaches 2.0 Pa · s with a decrease in Ce2O3 to 1–6%. An increase in temperature to 1550°C and a fixed basicity of 3–5 is accompanied by a significant decrease in viscosity, which does not exceed 0.35 Pa · s at a Ce2O3 content of 1–15%.

The effect of basicity on the phase composition, structure, viscosity and crystallization temperature of CaO–SiO 2 –Al 2 O 3 –MgO–B 2 O 3 fluorine-free slags was studied using vibrational viscometry and thermodynamic phase composition modeling in combination with Raman spectroscopy. The viscosity of the studied slags was established to depend mainly on the phase composition. Despite the complex reticular structure, consisting mainly of [SiO 4 ] and [BO 4 ] structural units with a large quantity of bridging oxygen, long slags (having a wide temperature range of viscosity variations) with low basicity possess high flowability in a liquid state as well as a low temperature of crystallization. This can be explained by the fact that the introduction of boron oxide is accompanied by the formation of a significant quantity of low-melting phases (CaO–B 2 O 3 , 2CaO–B 2 O 3 , and CaO–MgO–2SiO 2 ) in the slag, which reduces the slag crystallization temperature, as well as increases its overheating and decreases viscosity. At an increase in basicity, long slags smoothly transform into short ones (with a narrow temperature range of viscosity variations); moreover, their structure is simplified along with an increase in the quantity of high-melting phases. In this case, despite the structural simplification, the slag crystallization temperature increases, which leads to the reduction in the degree of overheating and an increase in the viscosity.

The effect of basicity and content of boron oxide on viscosity, crystallization temperature, phase composition, and structure of the СаО – SiO2 – B 2 O 3 – 12 % Cr 2 O 3 – 3 % Аl 2 O 3 – 8 % МgO fluorine-free slag system in the range of boron oxide content 3 – 6 % and basicity 1.0 – 2.5 is studied by vibrational viscometry, thermodynamic phase composition modeling (HSC Chemistry 6.12 (Outokumpu)), and Raman spectroscopy. It was found that physical properties of the studied slags mainly depend on the balance between the degree of structure polymerization, nature of the bond with it, and phase composition. With a low basicity of 1.0, slags are “long” and an increase in the content of boron oxide from 3 to 6 % makes them more fusible, reducing the crystallization temperature of the slag from 1340 to 1224 °C, and its viscosity from 1.0 – 0.8 to ~0.25 Pa·s at 1600 – 1660 °C, despite the significant complication of the structure, reflected in the growth of the bridging oxygen index BO from 1.10 to 1.49. With an increase in basicity, slags transfer from “long” to “short” and the content of calcium oxide increases, which, being a donor of free oxygen ions (O 2– ), acts as a modifier of the slag structure. Thus, with a basicity of B = (CaO/SiO 2 ) = 2.5, slags have a simpler structure (BO = 0.50 – 0.53) relative to slags with a basicity of 1.0, while the addition of boron oxide complicates it only slightly (an increase in BO from 0.5 up to 0.53). Increasing the concentration of B 2 O 3 lowers the crystallization temperature from 1674 to 1605 °C and the viscosity from 1.0 to 0.3 Pa·s at 1660 °C as a result of the formation of low-melting compounds (mostly 2CaO·B 2 O 3 ).

The influence of B2O3 on viscosity, crystallization temperature, phase composition, and structure of fluorine-free slags of the СаО–SiO2–B2O3–2 % Cr2O3–3 % Аl2O3–8 % МgO system in the range of boron oxide content from 0 to 6% and basicity (B = CaO/SiO2 ) equal to 1.0 is studied by vibrational viscometry, phase composition thermodynamic modeling in combination with raman spectroscopy. It is found that boron oxide-free slag has the simplest structure, as indicated by the average amount of bridging oxygen BO equal to 0.73, and has a higher viscosity compared to boron-containing slags of 0.85‒0.60 Pa•s in the temperature range of 1400‒1450°C, and crystallization temperature of 1402°C. This is due to the high proportion of high-temperature compounds in the formed slag. The introduction of 2 to 6% boron oxide complicates the structure of the slag, which is accompanied by an increase in the average amount of bridging oxygen BO to 0.98 and 1.28, respectively. The resulting four-coordination structural elements [BO4], [CrO4] and [AlO4] are embedded in the silicon-oxygen lattice of the slag and complicate it, which increases the degree of polymerization. However, the formation of low-melting eutectics CaO•B2O3 and 2CaO•B2O3 after introduction of 2 and 6% boron oxide, despite the complexity of the structure of the formed slags, leads to a decrease in crystallization temperature to 1346 and 1265°C, an increase in the degree of slag superheating and a decrease in its viscosity to 0.9 and 0.55 Pa•s already at 1350°C. Thus, the addition of boron oxide to slag, despite the structure complication of the formed oxide system, leads to an increase in the liquid mobility of the slag due to the formation of a high proportion of low-temperature phases and a decrease in the proportion of medium- and high-temperature phases and a lower binding energy of boron with oxygen compared to silicon

The viscosities of the slags of the CaO–SiO2–Cr2O3–3

The relevance of the development of modern technological solutions for the processing of niobium ore materials used for the production of complex ferroalloys of domestic deposits is shown. The need to develop new technological processes of processing is caused by the fact that when switching to new types of niobium concentrates, the chemical and phase compositions of the starting materials change, and, consequently, this leads to a change in the composition and properties of the melting products (both metallic and oxide). Using an electrovibration viscometer, the temperature dependences of viscosity were studied and the crystallization temperatures of oxide melts of the Nb2O5 – SiO2 – CaO – TiO2 – Al2O3 system were calculated. The compositions of the studied samples correspond to phosphorless niobium slags, which can be obtained by carbothermic method from rough concentrates. The samples were obtained by fusing oxide materials in a high-temperature laboratory electric furnace. On the basis of the obtained data, graphical dependences of viscosity – temperature are constructed. It was experimentally established that oxide melts containing 15 – 26 % Nb2O5 are more “long” (having a wide crystallization range) and unfavorable according to the characteristic viscosity – temperature dependence. An increase in the concentration of niobium pentoxide to 40 % translates slags into the category of “short” (with a high crystallization rate). It is shown that an increase in the concentration of niobium oxide Nb2O5 from 15 to 40 % leads to a decrease in the crystallization temperature of melts by 200 °C and a decrease in the viscosity of melts from 1.32 to 0.24 Pa·s at 1350 °C. The improvement of the physico-chemical characteristics of oxide melts with an increase in the concentration of niobium pentoxide can favorably affect the technical and economic indicators of ferroalloy production.

The article describes theoretical and experimental studies of dependence of viscosity, coefficients of sulfur and boron distribution between slag and metal, and wear degree of periclase-carbon refractories on basicity and boron oxide content in slag. It is shown that formed slags have basicity of 2.0 – 5.0 and rather high liquid mobility. These slags are characterized by an equilibrium interfacial distribution coefficient of sulfur increased to 5 – 20, which provides equilibrium sulfur content in the metal reduced to 0.001 – 0.005 %. The results of fundamental studies of the physicochemical properties of refining slags of СаО – SiO2 – В2O3 – Al2O3 – MgO system formed the basis for development of the composition of environmentally friendly fluorine-free ladle slags and technological methods for their formation in ladle-furnace unit. The recommended composition of such slags of low viscosity, which allows deep metal desulfurization, direct steel microalloying with boron and low aggressive effect on periclase-carbon refractories, provides formation of slags with a basicity of 3.0 – 4.0, containing 1 – 4 % B2O3 , 15 % Al2O3 and 8 % MgO. The formation of environmentally friendly ladle slags of the recommended composition was carried out in a ladle-furnace by loading lime, boron-containing material – colemanite (Turkey) containing 39 – 41 % B2O3 , 26 – 28 % CaO, not more than 5 % SiO2 and 3 % MgO, and pyramidal aluminum into the steel-teeming ladle for slag deoxidation and boron recovery. Introduction of the developed technology for the formation of ladle slags of recommended composition ensured the production of economically alloyed low-carbon structural boron-containing steels with a low sulfur content, incl. for large diameter pipes with high strength properties.

Thermodynamic modeling of the reduction of cerium from slags of the CaO–SiO2–Ce2O3 system containing 15% Al2O4 and 8% MgO, with aluminum dissolved in the metal together with calcium carbide additives at temperatures of 1550 and 1650°C was performed using the HSC 8.03 Chemistry software package (Outokumpu) based on the simplex lattice planning method used to minimize Gibbs energy. The results of thermodynamic modeling are presented in the form of composition-property diagrams (equilibrium content of cerium in the metal) for temperatures of 1550 and 1650°C. It is shown that the formation of slags within a basicity range of 2–3 containing 1–7% Ce2O3 provides an equilibrium concentration of cerium in the metal varying from 1 to 7 ppm at a temperature of 1550°C. The displacement of slags in the area of increased basicity (up to 3–5) is accompanied by an increase in the equilibrium concentration of cerium in the metal up to 7–23 ppm with a content of 3–7% Ce2O3 and as a consequence an increase in the efficiency of the process of cerium reduction. At a temperature of 1650°C, the equilibrium concentration of cerium in the metal within the basicity range of 2–3 and having a Ce2O3 content of 1–7% varies from 2 to 12 ppm. The displacement of slags in the area of increased basicity (up to 3–5) is accompanied by an increase in the equilibrium concentration of cerium in the metal to 7–33 ppm with a Ce2O3 content of 3–7%. The positive influence of the temperature factor basicity of slags and the content of cerium oxide on the process of its reduction is qualitatively explained from the standpoint of the formation of the phase composition of the slags of the studied oxide system and the thermodynamics of chemical reactions of reduction of cerium with aluminum dissolved in the metal, as well as with aluminum dissolved in the metal together with calcium carbide additives.