Slag corrosion of dolomite-carbon refractories

Seven industrial doloma refractory samples, coming from three European suppliers, and with different carbon, or graphite, or binder content, are subjected to the action of a slag required for the desulfurization of the steel in the secondary metallurgy at 1600°C. Three tests have been carried out within two induction furnaces. The corrosion depth, at the slag-steel interface, has been measured; the graphite-containing samples display a better resistance than the graphite-free pitch or resin-bonded refractories. Among the graphite-containing samples correlations have been found with the carbon content and with the resistance to oxidation by CO–CO₂ at 1100–1200°C. The slag-refractory interface has been investigated by X-ray diffraction, optical microscopy and electron microprobe analysis; the observed phases are CaO, MgO, Ca₂SiO₄, Ca₃SiO₅ and Ca₁₂Al₁₄O₃₃ (outside graphite and iron). The corrosion mechanism is linked to the reaction of slag with lime, followed by infiltration of the refractory and dispersion of periclase grains in the slag.     

Effect of basicity on wüstite sinter reducibility under simulated blast furnace conditions

Abstract

In this study, synthetic sinters with different basicity (CaO/SiO₂?=?0, 0·5 and 2·0) were prepared at 1300°C and prereduced at 900°C using low potential reducing gas (LPRG; 20%CO, 20%CO₂, 5%H₂ and 55%N₂). The prereduced sinters were subsequently reduced to metallic iron at 950–1100°C using relatively high potential reducing gas (HPRG; 30%CO, 5%CO₂, 10%H₂ and 55%N₂). Both LPRG and HPRG were selected to simulate the gas composition in the blast furnace upper and lower shaft respectively. High pressure mercury porosimeter, X-ray phase analysis, optical and scanning electron microscope were used for the analysis of the prepared and reduced sinters. In the original basic sinter, calcium ferrite (CaFe₂O₄) and dicalcium silicate (Ca₂SiO₄) phases were identified as well as the main Fe₂O₃ phase, whereas wollastonite [Ca_2·87Fe_0·13(SiO₃)₃] and silica (SiO₂) were formed in the acidic sinter. The prereduction in sinters with LPRG at 900°C resulted in the formation of wüstite (Fe_0·902O) phase. The subsequent reduction in wüstite sinters to metallic iron using HPRG at 950–1100°C was found to be the highest for basic sinter and the least for acidic sinter. The higher reduction rate of basic sinter was attributed to the enhancement of wüstite reducibility through the formation of calcium ferrites. The lower reduction rate of wüstite in acidic sinter was attributed to the formation of hard reducible fayalite (Fe₂SiO₄) and ferrobustamite [(Ca_0·5Fe_0·5)SiO₃] phases. The rate controlling mechanism during the reduction process was estimated by the correlation between apparent activation energy calculation and microstructure investigations.     

The Effect of Basic Oxygen Furnace Slag and Fly Ash Additions in Triaxial Porcelain Composition: Phase and Micro Structural Evolution

Basic oxygen furnace (BOF) slag generated in iron and steel industries were gradually added in a standard triaxial vitrified porcelain tile composition substituting feldspar. Fly ash, a by product of thermal power plant was used as filler by replacing quartz in part or full. The effect of such additions on the physico-mechanical properties of the samples fabricated by ceramic processing technique and heated in the temperature range of 1,050–1,200 °C have been investigated. Out of seven compositions studied, three were selected for detailed investigation on the basis of their lower vitrification temperature. Among three, two have shown early vitrification at 1,150 °C and resulted in highest flexural strength (>70 MPa), while another one vitrified at 1,200 °C and resulted in lower strength (~55 MPa). This variation in mechanical properties is correlated with their densification behaviour, XRD and SEM data. X-Ray diffraction studies confirm the presence of anorthite (CaAl₂Si₂O₈), mullite (Al₆Si₂O₁₃), fayalite(Fe₂SiO₄), quartz (SiO₂), enstatite(MgSiO₃). The weight percentages of crystalline and glassy phases have also been calculated form Rietveld analysis of XRD data. The SEM photomicrographs on selected vitrified specimens supported the XRD observation. The paper also discusses the application of such vitrified products in construction industries.     

The CaS solubility in the CaO bearing slags

The CaS solubility and sulfide capacity for the CaO–SiO₂–CaF₂ and CaO–Al₂O₃–SiO₂ systems have been measured at 1300°C and 1400°C, respectively. With the CaO–SiO₂–CaF₂ system, the slag doubly saturated with CaO and 3CaO · SiO₂ has the highest CaS solubility of 12.5 wt.%. On the liquidus the slag always has a higher CaS solubility than when it is not on the liquidus. The sulfide capacity was confirmed to decrease with increasing SiO₂ content. With the CaO–Al₂O₃–SiO₂ system, the CaS solubility was found to depend only on CaO content. A good correlation between the sulfide capacity and the CaS solubility was observed as expected from theory. The temperature dependence of CaS solubility in those systems was also discussed.     

A reinvestigation of phase equilibria in the system Al<Subscript>2</Subscript>O<Subscript>3</Subscript>-SiO<Subscript>2</Subscript>-ZnO

The phase equilibria and liquidus temperatures in the binary SiO₂-ZnO system and in the ternary Al₂O₃-SiO₂-ZnO system at low Al₂O₃ concentrations have been experimentally determined using the equilibration and quenching technique followed by electron probe X-ray microanalysis. In the SiO₂-ZnO system, two binary eutectics involving the congruently melting willemite (Zn₂SiO₄) were found at 1448±5 °C and 0.52±0.01 mole fraction ZnO and at 1502±5 °C and 0.71±0.01 mole fraction ZnO, respectively. The two ternary eutectics involving willemite previously reported in the Al₂O₃-SiO₂-ZnO system were found to be at 1315±5 °C and 1425±25 °C, respectively. The compositions of the eutectics are 0.07, 0.52, and 0.41 and 0.05, 0.28, and 0.67 mole fraction Al₂O₃, SiO₂, and ZnO, respectively. The results of the present investigation are significantly different from the results of previous studies.     

The Formation Process of Silico-Ferrite of Calcium (SFC) from Binary Calcium Ferrite

Silico-ferrite of calcium (SFC) is a significant equilibrium crystalline phase in the Fe₂O₃-CaO-SiO₂ (FCS) ternary system and a key bonding phase in the sintering process of fine iron ore. In this work, the formation process of SFC from binary calcium ferrite has been determined by X-ray diffraction and field-emission scanning electron microscopy. Experiments were carried out under air at 1473 K (1200 °C) by adding SiO₂ and Fe₂O₃ into CaO·Fe₂O₃ (CF). It was found that the formation of SFC is dominated by solid-state reactions in the FCS ternary system, in which Fe₂O₃ reacts with CaO·Fe₂O₃ to form the binary calcium ferrite phase. The chemical composition of binary calcium ferrite is Ca_2.5Fe_15.5O₂₅ and approximately Ca₂Fe₁₂O₂₀ (CaO·3Fe₂O₃). Then Si⁴⁺ and Ca²⁺ ions take the place of Fe³⁺ ion in preference located on the octahedral layers which belongs to (0 0 18) plane of binary calcium ferrite. The crystal structure of binary calcium ferrite gradually transforms from orthorhombic to triclinic, and the grain is refined with the addition of silica due to the smaller radius of Si⁴⁺ ion. A solid solution SFC forms completely when the content of SiO₂ reaches approximately 3.37 wt pct at 1473 K (1200 °C).     

The free energies of mixing of melts in the systems 2FeO-SiO2-2MnO-SiO2 and 2.33FeO-TiO2-2.33MnOTiO2

The free energies of mixing in melts in the system 2FeO · SiO₂-2MnO · SiO₂ at 1450°C and the system 2.33FeO · TiO₂-2.33MnO · TiO₂ at 1475°C have been obtained from measurement of the equilibrium Mn + FeO = Fe + MnO established between the melts and ironmanganese foils. Both systems exhibit ideal silicate mixing. The phase diagram for the system 2FeO-SiO₂-2MnO ·SiO₂ is calculated.     

Viscosity Measurements of “FeO”-SiO2 Slag in Equilibrium with Metallic Fe

The current study delivered the measurements of viscosities in the system “FeO”-SiO₂ in equilibrium with metallic Fe in the composition range between 15 and 40 wt pct SiO₂. The experiments were carried out in the temperature range of 1473 K to 1773 K (1200 °C to 1500 °C) using a rotational spindle technique. An analysis of the quenched sample by electron probe X-ray microanalysis (EPMA) after the viscosity measurement enables the composition and microstructure of the slag to be directly linked with the viscosity. The current results are compared with available literature data. The significant discrepancies of the viscosity measurements in this system have been clarified. The possible reasons affecting the accuracy of the viscosity measurement have been discussed. The activation energies derived from the experimental data have a sharp increase at about 33 wt pct SiO₂, which corresponds to the composition of fayalite (Fe₂SiO₄). The modified quasi-chemical model was constructed in the system “FeO”-SiO₂ to describe the current viscosity data.     

Fine controllable blue emission and its mechanism in Ce3+-doped orthosilicate solid solution phosphors for different plant growths

The designed Ce~(3+)-doped alkaline-earth silicate phosphors Ca_mSr_(2-m-n)Ba_nSiO_4:Ce~(3+),Li~+(CSBS:Ce~(3+))were synthesized by a high temperature solid-state reaction. The crystal field splitting and the centroid shift from the free ion energy of 5 d configuration were approximated from the spectrum for Ca_2SiO_4,Sr_2SiO_4 and Ba_2SiO_4 phosphors. The single-phase purity was checked by means of X-ray diffraction. Here,when the doped concentration of Ca~(2+) is less than 80%(m ≤1.6), we report the structural phase transformation from monoclinic system β-Ca_2SiO_4 to orthorhombic system α-Ca_2SiO_4. The phosphors excited by near-ultraviolet(NUV) light at wavelengths ranging from 200 to 400 nm demonstrate a broad asymmetric blue emission band. The emission peak wavelength redshifts firstly from 417 nm of Ca_2SiO_4 to 438 nm of Sr_(0.3)Ca_(1.6)SiO_4, and then blueshifts to 411 nm of Sr_2SiO_4, and the end of 401 nm of Ba_2SiO_4.These results indicate that the tunable blue-emission of the phosphors can be realized through changing the solid solution components, which has a potential use as a blue component for fabricated precision modulation LEDs light sources and auxiliaries of SSC plastics films for different plant growths.We discuss in detail the possible mechanism and energy diagram of the tunable blue luminescence in Ca_mSr_(2-m-n)Ba_nSiO_4:Ce~(3+),Li~+ phosphors.     

Experimental investigation into radiative heat transfer characteristics for mould fluxes containing transition oxides

Abstract

Infrared transmittance of glassy and crystalline mould fluxes was measured using a Fourier transform infrared spectrometer at room temperature. Radiation heat transfer from the steel shell to the mould was calculated by a model. The results indicate that transition metal oxides MnO, FeO and TiO₂ have a marked negative effect on infrared transmittance and radiation heat flux of glassy samples. With MnO, FeO and TiO₂ added, the reductions of radiation heat flux in glassy samples are 19–25%, 34–36%, 6–29% respectively. X-ray diffraction results indicated that the crystalline phase in transition oxides free samples was mainly Ca₄Si₂O₇F₂. After transition oxides MnO, FeO and TiO₂ added, Mn₂SiO₄, Fe₂SiO₄, CaTiO₃, Ca₂SiO₄ and other minor phases were also precipitated in mould fluxes. On account of strong refraction and scattering, the negative effect on radiation heat flux in crystalline samples was much larger than that in the glassy ones.     

Breakdown of copper-smelting slags with ammonium chloride

A hydrometallurgical method for processing copper-smelting slags with the help of ammonium chloride is proposed. A production flowchart of the process stage is developed. Breakdown of the slag with the help of ammonium chloride is investigated and recommendations on the equipment implementation of the process are given. The copper-smelting slag is formed by minerals Fe₂SiO₄, Zn₂SiO₄, CuFe₂O₄, and Ca₂SiO₄. Breakdown should be performed at 280°C for 4 h with constant stirring and ratio slag: ammonium chloride = 1: 2.     

Experimental study of phase equilibria in the “FeO”-ZnO-(CaO + SiO2) system with CaO/SiO2 weight ratios of 0.33, 0.93, and 1.2 in equilibrium with metallic iron

The pseudoternary sections “FeO”-ZnO-(CaO + SiO₂) with CaO/SiO₂ weight ratios of 0.33, 0.93, and 1.2 in equilibrium with metallic iron have been experimentally investigated in the temperature range from 1000 °C to 1300 °C (1273 to 1573 K). The liquidus surfaces in these pseudoternary sections have been experimentally determined in the composition range from 0 to 33 wt pct ZnO and 30 to 70 wt pct (CaO + SiO₂). The sections contain primary-phase fields of wustite (Fe _x Zn_1−x O_1+y ), zincite (Zn _z Fe_1−z O), fayalite (Fe _w Zn_2−w SiO₄), melilite (Ca₂Zn _u Fe_1−u Si₂O₇), willemite (Zn _v Fe_2−v SiO₄), dicalcium silicate (Ca₂SiO₄), pseudowollastonite and wollastonite (CaSiO₃), and tridymite (SiO₂). The phase equilibria involving the liquid phase and the solid solutions have also been measured.     

Crystallization Control in Metallurgical Slags Using the Single Hot Thermocouple Technique

With the single hot thermocouple technique (SHTT) the solidification behavior of metallurgical slags has been studied by in situ observation, constructing time–temperature–transformation (TTT) or continuous‐cooling‐transformation (CCT) diagrams. The SHTT is a unique apparatus that enables measurement of the slag sample temperature using a thermocouple while the sample is heated or cooled simultaneously. Due to the low heat capacity of the system sample/thermocouple high heating or cooling rates can be easily obtained (>3000°C/min). The following findings are reported in the present paper: (i) For the CaO–Al₂O₃ slag – 44% CaO, 56% Al₂O₃ (wt%) – the CCT diagram shows large differences between liquidus and the temperature for first crystals precipitation, even at low cooling rates, for example, 168°C below the liquidus when cooling at a rate of 6°C min^?1. (ii) For the CaO–SiO₂ slag – % CaO/% SiO₂ (wt%) = 0.7 – no crystal is observed for continuous cooling, even at low cooling rates, such as 10°C min^?1. During isothermal experiments crystallization was observed only at 1000°C with an incubation time of 76 s (average of six experiments, standard deviation 27 s). However, crystallization becomes much more intense for the CaO–SiO₂ slag when increasing the temperature after reaching lower temperatures (<1000°C), where probably the conditions for nucleation are better.     

A sintering study on the β-spodumene-based glass ceramics prepared from gel-derived precursor powders with LiF additive

Beta-spodumene (Li₂O·Al₂O₃·4SiO₂, LAS) powders were prepared by a sol-gel process using Si(OC₂H₅)₄, Al(OC₄H₉)₃, and LiNO₃ as precursors and LiF as a sintering aid agent. Dilatometry, X-ray diffraction (XRD), scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), and electron diffraction (ED) were utilized to study the sintering, phase transformation, microstructure, and properties of the β-spodumene glass-ceramics prepared from the gel-derived precursor powders with and without LiF additives. For the LAS precursor powders containing no LiF, the only crystalline phase obtained was β-spodumene. For the pellets containing less than 4 wt pct LiF and sintered at 1050 °C for 5 hours the crystalline phases were β-spodumene and β-eucryptite (Li₂O·Al₂O₃·2SiO₂). When the LiF content was 5 wt pct and the sintering process was carried out at 1050 °C for 5 hours, the crystalline phases were β-spodumene, β-eucryptite (triclinic), and eucryptite (rhombohedral (hex.)) phases. With the LiF additive increased from 0.5 to 4 wt pct and sintering at 1050 °C for 5 hours, the open porosity of the sintered bodies decrease from 30 to 2.1 pct. The grains size is about to 4 to 5 μm when pellect LAS compact contains LiF 3 wt pct as sintered at 1050 °C for 5 hours. The grains size grew to 8 to 25 μm with a remarkable discontinuous grain growth for pellet LAS compact contain LiF 5 wt pct sintered at 1050 °C for 5 hours. Relative densities greater than 90 pct could be obtained for the LAS precursor powders with LiF > 2 wt pct when sintered at 1050 °C for 5 hours. The coefficient of thermal expansion of the sintered bodies decreased from 8.3 × 10⁻⁷ to 5.2 × 10⁻⁷/°C (25 °C to 900 °C) as the LiF addition increased from 0 to 5 wt pct.     

Experimental study of phase equilibria in the “FeO”-ZnO-(CaO + SiO2) system with the CaO/SiO2 weight ratio of 0.71 at metallic iron saturation

The pseudoternary section “FeO”-ZnO-(CaO + SiO₂) with a CaO/SiO₂ weight ratio of 0.71 in equilibrium with metallic iron has been experimentally investigated in the temperature range from 1000 °C to 1300 °C (1273 to 1573 K). The liquidus surface in this pseudoternary section has been determined in the composition range of 0 to 33 wt pct ZnO and 30 to 70 wt pct (CaO + SiO₂). The system contains primary-phase fields of wustite (Fe _x Zn_1−x O_1−y ), zincite (Zn _z Fe_1−z O), fayalite (Fe _w Zn_2−w SiO₄), melilite (Ca₂Zn _u Fe_1−u Si₂O₇), and pseudowollastonite (CaSiO₃). The phase equilibria involving the liquid phase and the solid solutions have also been measured.     

Transformation of Ba-Al-Si precursors to celsian by high-temperature oxidation and annealing

Celsian (monoclinic BaO · A1₂O₃ · 2SiO₂) is being considered as a matrix material for ceramic composites used in high-temperature structural applications. The present article describes the synthesis of celsian by the oxidation and annealing of solid, malleable, metallic Ba-Al-Si precursors. The phase and microstructural evolution after various stages of oxidation at 300 °C to 1260 °C in pure oxygen at 1 atm pressure have been examined by X-ray diffraction (XRD) and electron microprobe analyses (EPMA). Barium peroxide, BaO₂, formed rapidly during oxidation at 300 °C, with aluminum and silicon remaining largely as unoxidized particles in a BaO₂ matrix. Between 300 °C and 500 °C, barium orthosilicate, Ba₂Si0₄, formed by a solid-state reaction between barium peroxide and unoxidized silicon. Further exposure to temperatures between 500 °C and 1200 °C resulted in the oxidation of aluminum and of residual silicon. The oxidized silicon reacted with the barium orthosilicate matrix to yield higher silica-containing barium silicates that, in turn, reacted with alumina or mullite to form metastable hexacelsian (hexagonal BaO-A1₂O₃ · 2SiO₂). Celsian was then obtained by further exposure to peak temperatures ≤1260°C.     

Phase Transformation and Morphology of Calcium Phosphate Prepared by Electrochemical Deposition Process Through Alkali Treatment and Calcination

The phase transformation and morphology of calcium phosphate prepared by the electrochemical deposition (ECD) process through alkali treatment and calcination have been characterized using X-ray diffraction (XRD), thermogravimetry and differential thermal analyses (TG/DTA), and scanning electron microscopy (SEM). At the ECD process, when the excess OH^? was produced, the reaction of 10Ca²⁺+6PO ₄ ^3? +2OH–→Ca₁₀(PO₄)₆(OH)₂ takes place on the Ti-6Al-4V and the HA is deposited. The XRD results reveal that the as-deposit was mostly composed of dicalcium phosphate dehydrate (Ca₂H₄P₂O₉; DCPD) and the minor phase of hydroxyapatite (Ca₁₀(PO₄)₆(OH)₂; HA). After NaOH treatment, all DCPD were converted to HA. Moreover, the content of HA phase increases with ECD potential. After being calcined at 673 K and 873 K (400  °C and 600  °C) for 4 hours, the phase of HA maintained the major phase for an alkali-treated deposited sample. After being calcined at 1073 K (800  °C) for 4 hours, some HA decomposed and caused the minor phases of β-tricalcium phosphate (β-Ca₃(PO₄)₂; β-TCP), calcium pyrophosphate (Ca₂P₂O₇; CPP), and calcium oxide (CaO) formation. The β-TCP becomes the major phase with residual HA and CaO after being calcined at 1273 K (1000  °C) for 4 hours. The crack forms due to the release of absorbed water from the interior to top surface of sample. For the as-alkali treatment samples, the microstructures were affected by ECD potentials; when the deposited samples after alkali treatment and calcined at 1073 K (800 °C) for 4 hours, the microstructure presents the need-like “preforming HA” (pre-HA) from the matrix of plate-like postforming HA (post-HA).     

Thermodynamic Modeling of Metal Desulfurization with Boron-Containing Slags of the CaO–SiO<Subscript>2</Subscript>–MgO–Al<Subscript>2</Subscript>O<Subscript>3</Subscript>–B<Subscript>2</Subscript>O<Subscript>3</Subscript> System

In thermodynamic modeling of the desulfurization of steel by CaO–SiO₂–MgO–Al₂O₃–B₂O₃ slag on the basis of HSC 6.12 Chemistry software (Outokumpu), the influence of the temperature (1500–1700°C), the slag basicity (2–5), and the B₂O₃ content (1–4%)1 on the desulfurization is analyzed. It is found that the sulfur content is reduced with increase in the temperature from 1500 to 1700°C, within the given range of slag basicity. At 1600°C, the sulfur content in the metal is 0.0052% for slag of basicity 2; at 1650°C, by contrast, its content is 0.0048%. Increase in slag basicity from 2 to 5 improves the desulfurization, which increases from 80.7 to 98.7% at 1600°C. If the B₂O₃ content in the slag rises, desulfurization is impaired. At 1600°C, the sulfur content in the metal may be reduced to 0.0052 and 0.0098% when using slag of basicity 2 with 1 and 4% B₂O₃, respectively; in the same conditions but with slag of basicity 5, the corresponding values are 0.00036 and 0.00088%, respectively. Note that desulfurization is better for slag without B₂O₃. According to thermodynamic modeling, metal with 0.0039 and 0.00019% S is obtained at 1600°C when using slag of basicity 2 and 5, respectively, that contains no B₂O₃. The results obtained by thermodynamic modeling for the desulfurization of metal by CaO–SiO₂–MgO–Al₂O₃–B₂O₃ slag of basicity 2–5 in the range 1500–1700°C are consistent with experimental data and may be used in improving the desulfurization of steel by slag that contains boron.     

In Situ Observation and Investigation of Mold Flux Crystallization by Using Double Hot Thermocouple Technology

The crystallization processes of mold fluxes for casting low-carbon (LC) and medium-carbon (MC) steels were investigated by using double hot thermocouple technology (DHTT) in this article. The results showed that the glass phase was first formed at the cold side thermocouple (CH-2), when the LC mold flux (mold flux for casting low-carbon steel) was exposed to the temperature gradient of 1773 K (1500 °C) to 1073 K (800 °C); then, the fine crystals were precipitated at the liquid/glass interface and grew toward glass and later on to liquid phase. However, the crystals were directly formed at CH-2 when MC flux (mold flux for casting medium-carbon steel) was under the same thermal gradient. The growth rate of MC flux crystals was much faster than that of LC ones. Scanning electron microscope (SEM) and X-ray energy dispersive spectroscopy (EDS) analyses suggested that the crystals formed in LC mold flux were mainly dendritic cuspidine Ca₄Si₂O₇F₂, and the crystals formed from the liquid phase were larger than those from the glass. For MC mold flux, the earlier precipitated crystals were large dendritic Ca₄Si₂O₇F₂, whereas the later ones were composed of equiaxed Ca₂Al₂SiO₇ crystals. The results of DHTT measurements were consistent with the time-temperature-transformation (TTT) diagrams and X-ray diffraction (XRD) analysis.     

Thermodynamic Simulation of the Influence of the Temperature and the Basicity of a Boron-Containing Slag on Steel Desulfurization

The results of thermodynamic simulation of the desulfurization of a medium-carbon steel by slags of the CaO–SiO₂–MgO–Al₂O₃–B₂O₃ system are presented. The HSC Chemistry 6.12 software package is used for the simulation. The thermodynamic simulation is performed for 20 various chemical compositions of slags with various B₂O₃ contents (1–4%)¹ and basicities ((CaO)/(SiO₂) = 2–5). The computations are performed using the Equilibrium Compositions module in the temperature range from 1500 to 1700°C with an increment of 50°C at a gas phase pressure of 0.1 MPa. The main results of the calculations are presented as the dependences of the change in the sulfur content in steel [S] on the temperature, the content of B₂O₃, and the slag basicity. An increase in the temperature of metal desulfurization from 1500 to 1700°C exerts a favorable effect on the sulfur content for the studied range of slag basicities. In particular, the sulfur content in steel decreases from 0.012 to 0.009% when steel is processed with the slag having 3% B₂O₃ and a basicity (CaO)/(SiO₂) = 2. A positive effect of an increase in the slag basicity from 2 to 5 on metal desulfurization is observed: the degree of desulfurization increases from 61.1 to 97.2% at 1600°C and 3% B₂O₃ content in the slag. As the B₂O₃ content in a slag increases from 1 to 4%, its refining properties decrease significantly in the range of basicity not higher than 2. In the range of high slag basicities (3–4), the negative effect of acidic oxide B₂O₃ on the refining properties of the slag decreases, providing low sulfur contents (which do not exceed [S] = 0.003–0.004% at 4% B₂O₃). At a slag basicity of 5, the sulfur content in steel decreases to 0.001%, all other things being equal. The simulation results can be used for the calculation of steel desulfurization processed by slags containing B₂O₃.