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Influence of the Slag Density on the Splashing Process in a Steelmaking Converter  [PDF]
Miguel A. Barron,Dulce Y. Medina,Isaias Hilerio,Gabriel Plascencia
ISRN Metallurgy , 2014, DOI: 10.1155/2014/525706
Abstract: The way in which slag density influences the slag splashing phenomenon in an oxygen steelmaking converter is numerically analyzed in this work. Several values of the density of the slag are considered, and their effect on the global mass balance and slag average volume fraction on the sidewalls of the converter is studied using isothermal, two-dimensional transient computational fluid dynamics simulations. Diameter of the slag drops is determined from the slag density and the impact velocity of the nitrogen jet. Besides, the effect of the nitrogen jet Mach number on the slag splashing is simulated and discussed. A qualitative comparison between the computer simulations and results from the literature is made. 1. Introduction It is known that the wear of refractory lining in an oxygen steelmaking converter for raw steel manufacturing is a factor which greatly influences the production costs. In the last two decades, slag splashing has emerged as a new technology to extend the lifetime of the converter refractory lining given that this technology reduces the wear associated to thermal and chemical attack by slag and mechanical impact [1, 2]. After the draining of steel, molten slag remaining at the converter bottom is splashed towards the converter sidewalls using a supersonic jet of gaseous nitrogen. Molten slag freezes at the converter walls and forms a protective coating that prevents the wear of the refractory lining. Nitrogen is injected into the converter through a water-cooled vertical lance which has several inclined convergent-divergent nozzles. During the slag splashing process three main stages have been identified in the formation of the slag protective coating: transport of molten slag to the converter walls, adherence of the molten slag to the sidewalls, and freezing and hardening of the slag layer [3]. When the molten slag is transported to the converter sidewalls, two transport mechanisms are present: wash coating and ejection coating [4]. The first one occurs due to the bulk movement of the molten slag to rise above the initial level and the second one due to the ejection of slag droplets which adhere to the vessel sidewalls [5]. In recent years, several experimental studies on the slag splashing phenomenon have been reported. In these studies, physical scale models of the converter are employed, and cold water and air replace molten slag and nitrogen, respectively [4, 6, 7]. In [4] it is reported that large nozzle inclination and lance heights increase the splashing and the main mechanism of splashing changes from ejection to washing as
The interfacial behavior of molten steel and liquid slag in a slab continuous casting mold with electromagnetic brake and argon gas injection

YU Hai-Qi,

金属学报 , 2008,
Abstract: It described a numerical simulation study for the interfacial behaviour between molten steel and liquid slag layer with different flow-control technologies in the slab continuous casting mold, considering the effects of argon gas flow rate, casting speed and current intensity of coils on the interfacial behaviour of molten steel and liquid slag with the coupling action of electromagnetic brake (EMBr) and argon gas injection. The relationship between the level fluctuation index of F value and level fluctuation of free surface was also investigated. For a given casting speed with EMBr, increasing the argon gas flow rate can aggravate the local fluctuation of interface so much as lead to the breakup of the steel-slag interface, F value increases with the increasing argon gas flow rate and the thickness of liquid slag near the meniscus increases linearly with F value. For a given argon gas flow rate with EMBr, increasing the casting speed has helpful for restraining the interfacial fluctuation near the nozzle, and F value also increasing, the thickness of liquid slag near the meniscus reduces linearly with F value. On the contrary, for a certain casting speed and argon gas flow rate, increasing the current intensity of coils can aggravate the steel/slag interfacial fluctuation near the nozzle.
Numerical Simulation for the Interfacial Behavior of Steel and Slag in a Slab Continuous Casting Mold with High Casting Speed

CAO Na,ZHU Miaoyong,

金属学报 , 2007,
Abstract: The entrainment of steel and slag interface has a great effect on casting process and the product quality. The research described the interfacial behavior between fluid steel and molten slag layer in a slab continuous casting mold with high casting speed by numerical simulation method. Good agreement between the mathematical model and experimental observation was obtained. The influences of casting speed, mold width, port angle, submergence depth of SEN and molten slag viscosity on interfacial behavior were investigated. For a given casting speed, increasing the penetration depth and downward port degree can effectively restrain interfacial oscillations. Molten slag viscosity has hardly influence on interfacial profile of steel and slag. Steel-slag interface velocity decreases with increasing molten slag viscosity.
Effect of slag composition on the cleanliness of 28MnCr5 gear steel in the refining processes  [PDF]
Wen-liang Dong,Hong-wei Ni,Hua Zhang,Ze-an Lü
- , 2016, DOI: https://doi.org/10.1007/s12613-016-1235-y
Abstract: The equilibrium reaction between CaO—Al2O3—SiO2—MgO slag and 28MnCr5 molten steel was calculated to obtain the suitable slag composition which is effective for decreasing the oxygen content in molten steel. The dissolved oxygen content [O] in molten steel under different top slag conditions was calculated using a thermodynamic model and was measured using an electromotive force method in slag–steel equilibrium experiments at 1873 K. The relations among [O], the total oxygen content (T.O), and the composition of the slag were investigated. The experimental results show that both [O] and T.O decrease with decreasing SiO2 content of the slag and exhibit different trends with the changes in the CaO/Al2O3 mass ratio of the slag. Increasing the CaO/Al2O3 mass ratio results in a decrease in [O] and an increase in T.O. To ensure that T.O ≤ 20 ppm and [O] ≤ 10 ppm, the SiO2 content should be controlled to <5wt%, and the CaO/Al2O3 mass ratio should be in the range from 1.2 to 1.6.

金属学报 , 1987,
Abstract: The migration of Ti between Ti-containing slag and molten iron was found to be controlled by the diffusion of Ti ions in slag under the experimental conditions. The apparent order of reaction was detected to be of quasi-zero, and the apparent activation energy to be 258kJ/mol. The effects of some factors such as content of Ti in slag, basicity and temperature on the rate of migration have been also discussed. It seems that the basicity of slag serves a dual influence: to increase the basicity in slag with higher TiO_2 content may restrain from the reduction of Ti, while with lower TiO_2 content may accelerate the Ti reduction. Two distinguished regions of the restraint and acceleration of the reduction of Ti by Si may be drawn by wt-% ratio Si]/Ti] on the basis of thermodynamical analysis.
Foaming Behavior in Molten Slag Caused by Decomposition of Carbonate Minerals
NIU Qiang,CHU Shao-jun,WU Keng,WANG Ying,
NIU Qiang
,CHU Shao-jun,WU Keng,WANG Ying

过程工程学报 , 2001,
Abstract: The average foam life is proposed as an index to the foaming behavior in molten slag. The molten slag system of Na_2B_4O_7-CaO-MgO is foamed by the gas from the thermal decomposition of carbonate minerals as the foamer. The experimental results show that foamer type and particle size have influence upon the average foam life of slag. The concentration of CaO and MgO in molten slag not only varies the physical properties of melt but also influences directly the decomposition rate of carbonate and the bubble size of gas, thus playing an important role in foaming and to foam stability of slag.
Steel desulphurization with synthetic slag  [cached]
Heput, T.,Ardelean, E.,Socalici, A.,Maksay, S.
Revista de Metalurgia , 2007,
Abstract: Generally speaking, sulphur is considered a harmful element for steel quality, reason why all the technological steps are being taken in order to eliminate it from the metal bath. This paper deals with the influence of the chemical composition, on the slag quantity and of the bath stirring condition upon the desulphurization process in the casting ladle by treatment with synthetic slag. The experiments were made at an open-hearth plant with the steel tapping in two ladles (the desulphurization was made with synthetic slag at one ladle while the other one was considered standard) and at the electric steel plant and for the synthetic slag formation a mix was used, made, according to several receipts, of: lime (50-75%), fluorine (0-17%), bauxite (0-32%) and aluminous slag (8-22%). The data were processed in the calculation programs EXCEL and MATLAB, which resulted in a series of correlations between the desulphurization degree and the chemical composition of the slag, respectively the slag quantity both for the charges bubbled with Argon and the unbubbled ones. En general, el azufre es considerado un elemento nocivo para la calidad del acero y, por eso, en la práctica, se toman todas las medidas de orden tecnológico para su eliminación del ba o metálico. En este trabajo se analiza la influencia de la composición química, de la cantidad de escoria y del estado de agitación del ba o sobre el proceso de desulfuración en la cuchara para fundir por tratamiento con escoria sintética. Los experimentos se han realizado en una acería evacuando el acero en dos ollas (en una cuchara se efectuó la desulfuración con escoria sintética y a la otra se consideró como patrón) y en un acería eléctrica y para la formación de la escoria sintética se utilizó una mezcla producida según muchas recetas, formada por: cal (50-75%), fluorina (0-17%), bauxita (0-32%) y escoria aluminosa (8-22%). Los datos han sido procesados en los programas de cálculo EXCEL y MATLAB, resultando una serie de correlaciones entre el grado de desulfuración y la composición química de la escoria, la cantidad de escoria respectivamente, tanto para las cargas burbujeadas con argón como no burbujeadas.
Steel Slag ingredient for concrete pavement
International Journal of Innovative Research in Science, Engineering and Technology , 2013,
Abstract: Steel slag is an industrial by-product of steel industry. It possesses the problem of disposal as waste and is of environmental concern [9]. The demand for aggregate in construction industry is increasing rapidly and so is the demand for concrete. Thus it is becoming more important to seek suitable alternatives for aggregates in the future. In this study, the natural coarse aggregates (NCA) were replaced with steel slag aggregate (SSA) at various proportions of 20%, 40%, 60%, 80% and 100%. Experiments were conducted to determine the compressive strength, flexural strength and split tensile strength of concrete with various percentages of steel slag aggregate. The results were compared with conventional concrete.
The Characterization of Steel Slag by Alkali Activation
Ikmal Hakem Aziz, Khairunnisa Zulkifly, Konstantinos Sakkas, Dimitrios Panias, Georgia Maria Tsaousi, Mohd Mustafa Abdullah Al Bakri, Heah Cheng Yong
Open Access Library Journal (OALib Journal) , 2017, DOI: 10.4236/oalib.1103816
This paper presents a characterization analysis of alkali-activated steel slag. The effect ratio of steel slag and ferronickel slag which are the precursor materials on the compressive strength of the alkali-activated materials was investigated. The combination of sodium hydroxide solution of 15 moles concentration and sodium silicate was used as an alkaline activator. The ratio between steel slag and alkaline liquid was fixed at 3.31 for all mixtures. Ambient curing (20℃ - 25℃) are used throughout the experiment. Compressive strength shows the alkali-activated steel slag presented high strength at 14 days curing which is 21.56 MPa. In comparison, the alkali activated steel slag had better strength than 50/50 Fe/SS alkali-activated slag which only achieved 16.75 MPa. Result obtained shows that alkali-activated steel slag had better water absorption than 50/50 Fe/SS alkali-activated slag at 7 days curing. Furthermore, the activation of steel slag was contributed to the presences of gehlenite, larnite, akermanite and magnetite. Lastly, the alkali-activated steel slag presents the vibration of the Si-O bonds at wave number 970.46 cm﹣1 contributed by the calcium silicate hydrate.
Rheological behavior and constitutive equations of heterogeneous titanium-bearing molten slag  [PDF]
Tao Jiang,De-ming Liao,Mi Zhou,Qiao-yi Zhang,Hong-rui Yue,Song-tao Yang,Pei-ning Duan,Xiang-xin Xue
- , 2015, DOI: https://doi.org/10.1007/s12613-015-1137-4
Abstract: Experimental studies on the rheological properties of a CaO–SiO2–Al2O3–MgO–TiO2–(TiC) blast furnace (BF) slag system were conducted using a high-temperature rheometer to reveal the non-Newtonian behavior of heterogeneous titanium-bearing molten slag. By measuring the relationships among the viscosity, the shear stress and the shear rate of molten slags with different TiC contents at different temperatures, the rheological constitutive equations were established along with the rheological parameters; in addition, the non-Newtonian fluid types of the molten slags were determined. The results indicated that, with increasing TiC content, the viscosity of the molten slag tended to increase. If the TiC content was less than 2wt%, the molten slag exhibited the Newtonian fluid behavior when the temperature was higher than the critical viscosity temperature of the molten slag. In contrast, the molten slag exhibited the non-Newtonian pseudoplastic fluid characteristic and the shear thinning behavior when the temperature was less than the critical viscosity temperature. However, if the TiC content exceeded 4wt%, the molten slag produced the yield stress and exhibited the Bingham and plastic pseudoplastic fluid behaviors when the temperature was higher and lower than the critical viscosity temperature, respectively. When the TiC content increased further, the yield stress of the molten slag increased and the shear thinning phenomenon became more obvious.
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