Search

Desulfurization of molten iron by molten slag is an electrochemical reaction. Previous investigations confirmed that applying electricity could enhance the desulfurization of molten iron, but a quantitative relation between the electricity and the desulfurization was not fully elucidated. The present study attempted to correlate the extent of the electrochemical desulfurization with the applied electricity via a series of high-temperature desulfurization experiments and thermodynamic analyses. A molten iron containing C and S was allowed to react with CaO– $$\hbox {Al}_{{2}}\hbox {O}_{{3}}$$ – $$\hbox {MgO}_{\text {sat.}}$$ slag at 1673 K (1400 $$^\circ $$ C), with and without the electricity of constant current. S distribution coefficients ( $$L_{\text {S}}$$ = (pct S)/[pct S]) were obtained after the normal and the electrochemical equilibria, respectively. The obtained results were interpreted by employing the Nernst equation in order to extract the potential difference ( $$\varDelta \phi _{\text {S}}$$ ) for the electrochemical desulfurization. It was found that applying electric current (I) increased the $$L_{\text {S}}$$ after the electrochemical desulfurization, which resulted in the increase of $$\varDelta \phi _{\text {S}}$$ . A resistance, $$R_{\text {DeS}} = \varDelta \phi _{\text {S}}$$ /I, or a specific resistivity, $$\rho _{\text {DeS}} = \varDelta \phi _{\text {S}}$$ /(I/A), where A is the cathodic area, for the electrochemical desulfurization was defined, which can be used to characterize the susceptibility to the electrochemical desulfurization. It was found that $$R_{\text {DeS}}$$ was independent of the I within the range of this investigation, decreased as (pct CaO)/(pct $$\hbox {Al}_{{2}}\hbox {O}_{{3}}$$ ) increased and was proportional to the resistance of the slag ( $$R_{\text {slag}}$$ ). A favorable condition for the electrochemical desulfurization is not the same as that for the normal desulfurization condition. The $$\varDelta \phi _{\text {S}}$$ , which is an indicator of the extent of electrochemical desulfurization, was independently predicted by employing a thermodynamic model for the oxysulfide slag. The model prediction was in a good agreement with the experimental data. The model was used to predict necessary current level for a desired electrochemical desulfurization.

Gold solubility in the CaO-SiO2-Al2O3-Fe2O3 slag system was measured at 1723 K under an oxidizing atmosphere. Gold solubility in the present slag system increased with increasing slag basicity, which was quantified by the Vee ratio (= CaO/SiO2), theoretical optical basicity, and activity of CaO. However, the effect of Fe2O3 and Al2O3 on gold solubility was negligible. From the thermodynamic assessment, it was found that gold was stabilized as the AuO− (aurate) complex ion, and thus the dissolution reaction into the slag was proposed. The aurate capacity was originally defined from the dissolution reaction. The iso-Au solubility contours were plotted in the CaO-Fe2O3-(SiO2 + Al2O3) pseudo-ternary diagram, from which the lower content of CaO can be proposed to be useful for higher recovery of gold (i.e., lower solubility) based on the thermodynamic view during pyrometallurgical processing of gold-containing E-waste materials. However, because the viscosity of the slag increases by decreasing the content of CaO, the operating window for best practice should be carefully proposed by considering the physicochemical properties of molten slag.

Slag–metal reaction experiments in MoSi2 resistance furnace combined with electroslag remelting (ESR) experiments in ESR furnace are used to study the effect of slag on zirconium distribution in ESR ingot by establishing a new mass transfer model of slag–metal reaction. The mass transfer model consists of Al + Al2O3, Si + SiO2, Zr + ZrO2, and Fe + FeO systems based on the penetration and film theories. Both experimental and simulated results show that the returned slag (CaF2:CaO:Al2O3:MgO:ZrO2 = 57:20:16:3:3) combined with extra 4% Al2O3 added into molten slag in the first slag-temperature-rising period can control the zirconium in ESR ingot ranging from 0.35 to 0.40% and improve the homogeneous distribution of zirconium in ESR ingot. The returned slag of Exp.A containing low silica being used in Exp.C can not only contribute to the recycling of returned slag, but also improve the homogeneous distribution of Zr along the height of ESR ingot.

To illuminate the corrosion behavior of MgO-based refractories under electromagnetic field (EMF), herein, the slag corrosion and penetration resistance of MgO–MgAl2O4, MgO–CaO, and MgO–C refractories were investigated using the rotary immersion slag resistance test at 1873 K for 1 h. The results showed that the order of the good slag resistance of as-tested refractories was MgO–C > MgO–CaO > MgO–MgAl2O4. The EMF accelerated the corrosion and penetration of slag to the refractories, which caused the molten slag to be easier into the refractories by natural convection and Marangoni effect. In addition, the MgO–C refractories did not show an overwhelming advantage in slag resistance because EMF impeded the formation of the dense protection layer. Consequently, in view of the present results, the MgO–C refractories are still the most promising slag line material for refining furnace among MgO–MgAl2O4, MgO–CaO, and MgO–C refractories.

MgO-based refractories have been widely used in metallurgical processes. However, their service lives are limited by the corrosion and penetration effects of the molten slag. To figure out the slag resistance of various MgO-based refractories, MgO–MgAl2O4, MgO–CaO, and MgO–C refractories were chosen in this work, and their slag corrosion characteristics under vacuum electromagnetic fields were investigated using the static crucible method at 1873 K. Furthermore, the corroded interfaces of refractories were analyzed by x-ray diffractometer (XRD), scanning electron microscope (SEM), and energy dispersive spectrometer (EDS). It was found that in CaO–Al2O3–SiO2–MgO slag system, the refractories displayed different slag corrosion resistance, and their corrosion depths ranged from 3 to 10 mm. The corrosion depths of MgO–CaO refractories were more than 10 mm, which showed the worst slag resistance performance. Among them, MgO–C refractories were hardly corroded by the molten slag and its corrosion depth was less than 3 mm.

The slag corrosion and penetration behaviors of MgAl2O4, MgAl2O4–ZrO2, MgAl2O4–ZrO2–CaO, Al2O3, and Al2O3–ZrO2–SiC refractories were investigated using the static crucible method at 1873 K for 2 h. The above refractories all displayed excellent slag corrosion resistance, and their corrosion depth was less than 1.10 mm. Al2O3 material was hardly corroded by the molten slag, and its corrosion depth was only 0.05 mm. Their penetration depth ranged from 13.79 to 24.48 mm. Among them, Al2O3–ZrO2–SiC refractories displayed good slag penetration resistance with a penetration depth of 13.79 mm.

The reactive wetting behavior of molten CaO–SiO2–Al2O3–MgO slag drops on a coke substrate was investigated using the sessile drop method at 1500 °C in flowing Ar. The wetting behavior of slags in blast furnaces is known to affect the energy efficiency of ironmaking, but has not yet been sufficiently characterized. In this study, the ratio of MgO to CaO was varied from 0.01 to 0.56, while the concentrations of SiO2 and Al2O3 were fixed at 34 and 17 wt%, respectively. The contact angle between slag and coke remained constant for a certain period of time, and then suddenly decreased remarkably. The time until this dramatic contact angle change increased with increasing the ratio of MgO to CaO. Chemical analysis revealed that the reduction of SiO2 in the slag improved the wettability by forming SiC on the coke substrate, while MgO in the slag was preferentially reduced and prevented the reduction of SiO2. Consequently, with increasing MgO content, the wettability of the molten slag on the coke substrate decreased.

Dynamic studies on the volatilization of lead from CaO–SiO2–Al2O3 molten slags were conducted in a lab-scale melting furnace from 1623 to 1773 K under different mixed gas atmospheres of CO 0.05–0.3 atm to CO2 0–0.3 atm to N2 (balance), HCl 1.7 × 10−3–6.7 × 10−3 atm to N2 (balance), and H2S 3.0 × 10−4 to 1.7 × 10−3 atm to N2 (balance). The slag samples consisted of the mixed powders of 20–50 wt% CaO, 30–60 wt% SiO2, and 10–40 wt% Al2O3, containing 2000 ppm PbO.Results showed that the rates of volatilization of lead from the CaO–SiO2–Al2O3 molten slags under the N2–CO–CO2, N2–HCl, and N2–H2S gas atmospheres were higher than those under the simulated air (N2–O2), which increased with CO, HCl, and H2S partial pressures. At $$p_{{HCl}}$$ = $$p_{H_{2}S}$$ = 1.7 × 10−3 atm, the apparent rate constants for the volatilization of lead under the N2–H2S and N2–HCl gas atmospheres were nearly equal, which increased with a rise in temperature. Results also showed that the rate of volatilization of lead from the molten slag decreased drastically with the increasing viscosity of the molten slag, in the viscosity range lower than 3 Pa s. Consequently, the volatilization of lead from the CaO–SiO2–Al2O3 molten slag was significantly influenced by CO, HCl, and H2S partial pressures and by the viscosity of the molten slag.

Results are provided for an experimental study of an improvement in periclase-carbon torcrete-mix slag resistance by a reduction in molten slag corrosiveness and modification of refractory composite microstructure. Combination of the refractory microstructure modification obtained and slag with changed chemical composition makes it possible to improve torcrete-mix properties considerably and increase its corrosion slag resistance.

A simple model for estimating the rate constant between CO2-CO gas and molten slag containing iron oxides was developed using optical basicity only. In this model, the temperature dependence of the rate constant can be described by the Arrhenius law, and the activation energy can be expressed with a linear function of the slag’s optical basicity. The model was applied to some molten slag systems, such as FeO, FeO-CaO, FeO-SiO2, FeO-Na2O, FeO-CaO-SiO2, FeO-SiO2-P2O5, FeO-SiO2-Na2O, and FeO-CaO-SiO2-P2O5. A comparison between the predicted results and measured data showed that the model worked well.

The dephosphorization of metallurgical-grade Si using molten slags has recently attracted much attention. In the current study, the thermodynamic assessment of an Si-P system was first carried out, and then the dephosphorization reaction equilibria between molten Si and CaO-based slags were calculated using the thermodynamic databases for Si alloy and slags. The thermodynamic calculations show that dephosphorization of Si under oxidizing conditions (in the form of phosphate) merely happens, and the dephosphorization under reducing conditions (in the form of phosphide) can cause the significant dissolution of Ca in molten Si.

The performance of pyrometallurgical slag cleaning furnaces at many primary copper smelters is dependent in part on the quality of the converter slag, commonly produced in the batch-wise Peirce Smith converter (PSC). In order to understand the impact of converter slag chemistry and at the same time help optimize the converter operation, thermodynamic modeling of molten slag (including any contained slag solid fractions) was carried out on slag produced at the Chagres smelter in Chile. Phase characterization studies on actual plant slag samples were also carried out. The results are provided in the present paper. This work is also considered as a case study example to illustrate the type of work that can be performed to fairly quickly diagnose the quality of converter slag and assess the overall condition of the converter operation.

Professor Fruehan has been a pioneer in the fundamental understanding of slag foaming in ironmaking and steelmaking processes. Although considerable progress has been made in our understanding of the phenomena, there are still unanswered questions regarding the mechanisms in industrial processes and how to control them. At McMaster University, we have been working on conditions that are relevant to foaming in electric arc furnaces (EAFs) where these phenomena are central to modern EAF practices. This work will be reviewed and put in the context of what is known from a fundamental standpoint.

The activity of Fe t O is very important in ironmaking and steelmaking process. In order to predict the activity of Fe t O and optimize the operation conditions in ironmaking and steelmaking process, by application of regular solution model in molten slag systems, FeO-Fe 2 O 3 -SiO 2 ternary system, FeO-Fe 2 O 3 -SiO 2 -CaO and FeO-Fe 2 O 3 -SiO 2 -NiO quaternary systems have been studied by the chemical equilibrium between H 2 /H 2 O gas mixture and liquid slag contained in solid iron. The values of interaction energy between cations concerning steelmaking slags have been determined by application of ferric-ferrous iron equilibrium and iron-ferric iron equilibrium. And then the activity of Fe t O can be calculated. The results show that the relative error is 3. 9% in FeO-Fe 2 O 3 -SiO 2 system and 18% in FeO-Fe 2 O 3 -SiO 2 -CaO system. The prediction of activities of Fe t O in the systems are in good agreement with the measurements and the regular solution model is valid for predicting the activity of Fe t O in complex molten slags systems. The activity of Fe t O in FeO-Fe 2 O 3 -NiO system have not been tested presently, and the calculated result can not be assessed.

With a goal to estimate the sulfide capacities of slags used in the pretreatment of hot metal, the sulfide capacities of CaO-Al2O3-SiO2 slags were measured at 1673 K to 1773 K (1400 °C to 1500 °C). The gas–slag equilibrium technique has been used for this measurement. From the results obtained, it was found that the temperature dependence of the sulfide capacity of this slag is independent of the slag compositions. Therefore, a new empirical model based on optical basicity for sulfide capacity estimation of this slag was developed using the measured values of the current work and literature. With the use of the new model, the isosulfide capacity curves at 1673 K (1400 °C) were mapped.

Al-Ti-O inclusions always clog submerged nozzles in Ti-bearing Al-killed steel. A typical synthesized Al2TiO5 inclusion was immersed in a CaO-SiO2-Al2O3 molten slag for different durations at 1823 K. The Al2TiO5 dissolution paths and mechanism were revealed by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Decreased amounts of Ti and Al and increased amounts of Si and Ca at the dissolution boundary prove that inclusion dissolution and slag penetration simultaneously occur. SiO2 diffuses or penetrates the inclusion more quickly than CaO, as indicated by the w(CaO)/w(SiO2) value in the reaction region. A liquid product (containing 0.7–1.2 w(CaO)/w(SiO2), 15wt%–20wt% Al2O3, and 5wt%–15wt% TiO2) forms on the inclusion surface when Al2TiO5 is dissolved in the slag. Al2TiO5 initially dissolves faster than the diffusion rate of the liquid product toward the bulk slag. With increasing reaction time, the boundary reaches its largest distance, the Al2TiO5 dissolution rate equals the liquid product diffusion rate, and the dissolution process remains stable until the inclusion is completely dissolved.

The enrichment behavior of phosphorus in CaO-SiO 2 -FeO x -P 2 O 5 slag was studied by making an investigation on the distribution of phosphorous content in the CaO-SiO 2 -FeO x -P 2 O 5 molten slag. The research results showed that the 2CaO • SiO 2 solid particles existing in molten slag were the condensation sites for the phosphorus enrichment. The enrichment process of phosphorus in the molten slag can be recognized as three substeps: mass transfer of phosphorus from bulk slag to the surface of 2CaO • SiO 2 particle, superficial solid solution reaction of phosphorus around the 2CaO • SiO 2 particle, and diffusion of phosphorus through the product layer of 2CaO • SiO 2 -3CaO • P 2 O 5 solid solution to the inner of 2CaO • SiO 2 particle. Moreover, higher temperature is favorable to the phosphorous enrichment from molten bulk slag to the 2CaO • SiO 2 particles.

Results are provided for a study of the slag resistance of periclase-carbon specimens based on modified phenol formaldehyde resin using different forms of filler, i.e., sintered and fuzed periclase. It is established that penetration of molten slag and its reaction with refractory is independent of the form of periclase filler. There is a reduction in slag penetration into refractory with introduction of modifying additions.

Modified quasi-regular solution model has been available based on the sub-regular solution model and quasiregular solution model in this article. The three parameters of this model are set by the computer-aided analysis based on the experimental data of activity at two different temperatures. Seven binary molten slag systems in the whole concentration are calculated by application of the model and the average relative error is within 10%. Ten binary molten slag systems presenting saturation concentration are also calculated, but the average relative error is bigger, especially for the systems containing acidic oxide and neutral oxide. The results show that the calculated results are superior to those calculated by application of regular solution model, sub-regular solution model and quasi-regular solution model.

A new model is proposed to estimate the density of molten slag, in which the temperature dependence of density is described by Arrhenius Law with the activation energy expressed as the linear function of optical basicity. Successful applications to the density calculations of CaO-Al 2 O 3 -SiO 2 and Al 2 O 3 -CaO-MgO-SiO 2 slag systems show that this formula can give a good description of composition and temperature dependence of density for molten slags. It is also found that the ionic band percentage of M-O band in MO x oxide is the intrinsic origin of the phenomenon that the slag with a high optical basicity has a large sensitivity to temperature.

Electrical conductivity of molten slag is an important physicochemical property for designing the refining process in electric smelting furnaces. Though conductivities of many slag systems have been measured, the quantitative relationships of conductivity with slag composition and temperature are still very limited. In this article, the Arrhenius law was used to describe the experimental data of conductivities for CaO-MgO-Al 2 O 3 -SiO 2 , CaO-Al 2 O 3 -SiO 2 , CaO-MnO-Al 2 O 3 -SiO 2 , as well as CaO-MgO-MnO-Al 2 O 3 -SiO 2 systems, and it is found that activation energy can be expressed as a linear function of the content of components, where the optical basicity of slag must be within the range of 0.58 to 0.68.

To reutilize molten slag derived from an ash melting process, the lead volatilization mechanism under reducing conditions was investigated. Reducing conditions were established by introducing a CO-CO2-N2 gas mixture to the reactor or by adding graphite to the molten slag prior to the experiments. As samples, two types of simulated molten slag composed of CaO-SiO2-Al2O3 mixed with PbO were used and the lead volatilization behavior was studied at 1773 K. It was found that the lead volatilization rate increased on increasing the amount of reducing agent for both graphite and the CO-CO2 gas mixture. For the CO-CO2 reducing gas mixture, this increase was mainly attributed to PbO conversion to Pb. For the addition of graphite, the increase in lead volatilization ratio was considered to partially result from PbO conversion to Pb and partially from a reaction of graphite with SiO2 yielding volatile SiO. The volatile SiO gas was then emitted from the furnace, which brought about a reduction in the SiO2 content of the slag. As a result, the slag viscosity decreased, which led to an enhancement of the lead volatilization ratio.

Recently with the aim of increasing the stability of converter linings there has been extensive use of a new class of synthetic magnesia modifiers that are added directly to the converter melt during steel melting. The chemical composition of modifiers and method for their preparation are provided. The basis of the magnesia modifiers is MgO oxide and its compounds. Modifier properties (density, open porosity) are studied in relation to a change in specimen heating and the mineral composition of modifiers of different chemical composition, and the change in the structure of modifier specimens during heating is examined. The mechanism of modifier dissolution in molten slag is suggested.

In this article, a novel thermodynamic model—the molecular interaction volume model (MIVM)—was employed to predict the activities of three components in the ternary molten slag CaO-FeO-SiO2 at different temperatures. The results show that the predicted values of activity of CaO and SiO2 are in reasonable agreement with the experimental data in a range of lower concentrations, which are about xCaO

Overview of running research activities — Study on the melt flow in the hearth of the iron making blast furnace — Green energy for metals production — Advanced process modelling of hot metal desulphurization by injection of Mg and CaO — Inclusion engineering — High performance casting — Development of the oxygen steelmaking process — Simulation of a continuous steel reheat furnace — Simulation of a mobile heat treatment furnace — Simulation and optimization of phosphorus production

“Waste molten slag” is a glass-like material produced by the vitrification of solid waste or solid waste incineration residue. When using slags of this kind in a natural environment, their impact is anticipated to be at the same level as competitive or substituted materials. In this study, we made comparative evaluations between waste molten slags and competitive materials, using 20 samples in total. It was proved that release fluxes of metals from molten slags of municipal solid waste were almost at the same level as competitive or substituted materials. However, a larger impact will be caused from some types of slag that contain harmful metals in high concentrations, such as the slag from shredded automobile residues. The results of release flux showed that nearly 80% of the slope of the flux did not fit with the diffusion range. However, the linearity of every flux was extremely high, regardless of the slope.

Original software that makes it possible to predict the viscosity of coal slag from data on its chemical composition as applied to results of domestic measurements is presented. The predictions are more accurate than those ensured by known domestic and foreign methods. The reliability of results is increased without changing the computational procedure by widening and amending the databank. A refined algorithm and software are suggested for computing the cyclic load capability of boilers from conditions of slag-tap removal. The method is based on integral computation of heat exchange in the combustion zone. The software has been tested for TP-87 and PK-40 boilers firing Kuznetskii coals of grades SS and T and for BKZ-320-140PT boiler firing Kansko-Achinskii coals.

This article reports the operational results of the effective utilization of hospital waste molten slag produced using a high-temperature melting system, and being operated at a hospital in Selangor, Malaysia. The hospital waste is incinerated and subsequently melted at 1200°C. Scanning election microscope (SEM)/EDX results showed that the slag produced after melting contained amounts of SiO2, CaO, and Al2O3 in excess of 53%, 9%, and 16%, respectively. The results from a leaching analysis on the slag produced proved that the melting process had successfully stabilized the heavy metals. The use of this slag as an alternative material to replace conventional aggregates for road construction was studied. The results from aggregate and asphalt mix tests showed that the slag produced fulfills all the requirements of an alternative aggregate. The average asphalt content, or the optimum asphalt content to be mixed with hospital waste molten slag, was found to be about 5.53%.

Viscosities of molten metals and slags play vital roles in many high-temperature phenomena that are important for advancing process control and product quality in molten-metal processing and casting. Because measuring viscosities of high-temperature melts is expensive, the need exists for reliable viscosity estimation methods based on the temperature and composition of the melt. This paper reviews some available models for alloys and slags, and examples are shown for melts of interest to both ferrous and non-ferrous processing

A mathematical model has been developed to simulate numerically the interactions between gas bubbles and molten steel during the gas-injection treatment in secondary refining of steel and to experimentally verify the reliability of the model. A marker-and-cell (MAC) technique is employed to simulate the motions of gas bubbles and molten steel. Photographic observation is used to evaluate the reliability of the mathematical model. A two-dimensional ladle with only one bubble was used to test the capability of the model to handle the interaction between the relatively large bubble and the molten steel. The shape of the bubble is initially round. Then it gradually becomes flattened and eventually evolves into a spherical-cap bubble. Molten steel is induced to flow and forms two circulations. The model was then tested on the same ladle with bubbles continuously released. The first bubble rises in a similar way as the previous case. The second bubble is affected by the first bubble and becomes slightly elongated in the vertical direction rather than in the horizontal direction. It also rises faster and later collides with the first bubble. The released bubbles can be grouped in clusters and are repeated cluster after cluster. Water-model experimental observations are consistent with the predicted results.

In the present work, a solid solution of 3CaO · V2O5 and 3CaO·P2O5 was found below 1573 K. The solution could be described as 3CaO+xV2O5+(1−x) P2O5. The solid solutions at three compositions, namely, X=1/3, X=1/2, and X=2/3, were synthesized. X-ray diffraction (XRD) patterns revealed that the crystals exhibited a rhombohedra structure. X-ray indexes at these compositions were reported.

The effect of magnesium oxide on the phase composition of metallurgical slag is studied. Heterogeneity of the slag and its final melting point are shown to increase with MgO concentration. A model for the slag infiltration into a periclase refractory is considered. A nomogram is plotted to show the dependence of the depth of slag penetration on slag viscosity, contact angle, surface tension, pore radius, and molten slag-refractory contact time.

Silicon-oxygen equilibria in an Fe-0.003 ~ 27 mass pct Si alloy in equilibrium with the CaO-SiO2 slags were studied in the temperature range of 1823 to 1923 K using a lime crucible. At the same time, nitrogen distribution ratios, LN, between slag and metal were measured, and from these results and the reported values for activities of SiO2, nitride capacities, % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfKttLearuqr1ngBPrgarmWu51MyVXgatC% vAUfeBSjuyZL2yd9gzLbvyNv2CaeHbd9wDYLwzYbItLDharyavP1wz% ZbItLDhis9wBH5garqqtubsr4rNCHbGeaGqiVy0df9qqqrpepC0xbb% L8F4rqqrFfpeea0xe9Lq-Jc9vqaqpepm0xbba9pwe9Q8fs0-yqaqpe% pae9pg0FirpepeKkFr0xfr-xfr-xb9adbaqaaeGaciGaaiaabeqaam% aaeaqbaaGcbaaceiGaa83qamaaBaaaleaaiqaacaGFobWaaWbaaWqa% beaacaGFZaGaeyOeI0caaaWcbeaaaaa!3DDE! $$C_{N^{3 - } } $$ , defined by (mass pct N). % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfKttLearuqr1ngBPrgarmWu51MyVXgatC% vAUfeBSjuyZL2yd9gzLbvyNv2CaeHbd9wDYLwzYbItLDharyavP1wz% ZbItLDhis9wBH5garqqtubsr4rNCHbGeaGqiVy0df9qqqrpepC0xbb% L8F4rqqrFfpeea0xe9Lq-Jc9vqaqpepm0xbba9pwe9Q8fs0-yqaqpe% pae9pg0FirpepeKkFr0xfr-xfr-xb9adbaqaaeGaciGaaiaabeqaam% aaeaqbaaGcbaWaaSGbaeaacqWGqbaudaqhaaWcbaacbaGae83ta80a% aSbaaWqaaGabaiaa+jdaaeqaaaWcbaWaaSGbaeaacaGFZaaabaGaa4% hnaaaaaaaakeaacqWGqbaudaqhaaWcbaGae8Nta40aaSbaaWqaaiaa% +jdaaeqaaaWcbaWaaSGbaeaacaGFXaaabaGaa4Nmaaaaaaaaaaaa!441C! $${{P_{O_2 }^{{3 \mathord{\left/ {\vphantom {3 4}} \right. \kern-\nulldelimiterspace} 4}} } \mathord{\left/ {\vphantom {{P_{O_2 }^{{3 \mathord{\left/ {\vphantom {3 4}} \right. \kern-\nulldelimiterspace} 4}} } {P_{N_2 }^{{1 \mathord{\left/ {\vphantom {1 2}} \right. \kern-\nulldelimiterspace} 2}} }}} \right. \kern-\nulldelimiterspace} {P_{N_2 }^{{1 \mathord{\left/ {\vphantom {1 2}} \right. \kern-\nulldelimiterspace} 2}} }}$$ were evaluated. It was found that the values for LN decreased, whereas those for % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfKttLearuqr1ngBPrgarmWu51MyVXgatC% vAUfeBSjuyZL2yd9gzLbvyNv2CaeHbd9wDYLwzYbItLDharyavP1wz% ZbItLDhis9wBH5garqqtubsr4rNCHbGeaGqiVy0df9qqqrpepC0xbb% L8F4rqqrFfpeea0xe9Lq-Jc9vqaqpepm0xbba9pwe9Q8fs0-yqaqpe% pae9pg0FirpepeKkFr0xfr-xfr-xb9adbaqaaeGaciGaaiaabeqaam% aaeaqbaaGcbaaceiGaa83qamaaBaaaleaaiqaacaGFobWaaWbaaWqa% beaacaGFZaGaeyOeI0caaaWcbeaaaaa!3DDE! $$C_{N^{3 - } } $$ increased with an increase in temperature. Activities of SiO2 were determined using the values for LN and % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfKttLearuqr1ngBPrgarmWu51MyVXgatC% vAUfeBSjuyZL2yd9gzLbvyNv2CaeHbd9wDYLwzYbItLDharyavP1wz% ZbItLDhis9wBH5garqqtubsr4rNCHbGeaGqiVy0df9qqqrpepC0xbb% L8F4rqqrFfpeea0xe9Lq-Jc9vqaqpepm0xbba9pwe9Q8fs0-yqaqpe% pae9pg0FirpepeKkFr0xfr-xfr-xb9adbaqaaeGaciGaaiaabeqaam% aaeaqbaaGcbaaceiGaa83qamaaBaaaleaaiqaacaGFobWaaWbaaWqa% beaacaGFZaGaeyOeI0caaaWcbeaaaaa!3DDE! $$C_{N^{3 - } } $$ obtained in previous gas-slag experiments. These values were compared with the previous results.

An automatic system for rapid determinations of the activities of FeO in metallurgical slags has been developed. With this facility, one datum is obtainable within 5 minutes. The facility was applied for the activity measurements in the system CaO + SiO2 + FeO, while activity data obtained were consistent with those deduced from the phase diagram.

Unexposed scaliness lowers the impact strength of MSR steel in the direction transverse to rolling. In this case, the higher the hardness of the steel, the greater the degree of reduction in a1. For a hardness of 42 HRCe, MSR steel with unexposed scaliness in the form of short bright striations over the entire fracture surface has a 35% lower impact strength in the direction transverse to rolling than steel in which this defect does not exist.

Determination du coefficient d'activite de nitrure de calcium dans les laitiers (Ca-CaF 2 ) par la mise en equilibre du systeme laitier-Fe solide-alliage Ag-Ca entre 1400 et 1450 o C. Calcul a partir de donnees obtenues de la repartition de l'azote entre le laitier et le bain metallique (alliage Fe-Cr) a 1873 K

A comparison is presented between the experimentally measured velocity field in a room temperature model of an ESR system and theoretical predictions, obtained from the numerical solution of Maxwell’s equations and the turbulent Navier-Stokes equations. The experimental measurements were obtained in a horizontal trough, containing mercury, through which a current was being passedvia two electrodes. The velocity fields, which were measured, using a photographic technique were thought to model the electromagnetically driven component of the velocity field in the central plane of the slag phase in ESR systems. The agreement between the experimental measurements and the theoretical predictions is excellent, both regarding the absolute values of the velocities and the dependence of the velocity on the imposed current and on the electrode diameter. The calculations have shown that by the proper choice of the linear scale, and the current,. mercury may be used to model the electromagnetically driven flow in the slag phase of ESR systems. Furthermore, some general relationships have been developed showing the effect of the current on the velocity, the turbulence energy, and on the rate of turbulence energy dissipation. This work is thought to provide definite confirmation that the electromagnetically driven component of the velocity fields in ESR systems may be properly represented through the simultaneous solution of Maxwell’s equations and the turbulent NavierStokes equations.