The composition and properties of blast furnace slags greatly affect the furnace productivity and the quality of hot metal produced. Viscosity is an important physical property of slags, strongly influenced by the chemical composition, structure and the temperature. Experimental measurement of slag viscosity requires high temperature equipment and is time consuming. Therefore, chemical parameters are used to identify trends in viscosity as function of chemical composition. Limited information is available for High Alumina Blast Furnace Slags, since much of the open literature deals with Low Alumina Slags, with alumina content less than 15 weight percentage. High Alumina slags (alumina content in the range of 15% to 30%) are predominantly encountered in Indian Blast Furnaces. It appears that these slags have higher viscosity and lower sulphide capacity than the low alumina slags. The effect of chemical composition / ionic structure on viscosity has been interpreted in this work, using the chemical parameter of optical basicity. Data reported in the literature have been used, along with the values of liquidus temperature, for high alumina slags. Three slag systems, i.e., CaO-Al2O3-SiO2, CaO-Al2O3-SiO2-MgO and CaO-Al2O3-SiO2-MgO-TiO2 have been considered in this work. The trends observed are discussed in the paper

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Viscosity is an important physical property, which influences the performance of slags, in metallurgical processes such as iron making, steelmaking and continuous casting. Viscosity of slags is strongly influenced by the chemical composition and the temperature. Experimental measurement of slag viscosity requires high temperature equipment and is time consuming. Empirical relations/calculations using certain chemical parameters have been attempted to predict the viscosity, which may then be used for controlling metallurgical processes. Metallurgical slags used in the steel industry are made up of different oxides and fluorides, and may often be treated as silicates. The presence of silica, an inorganic polymer, in slags, has a major impact on "viscosity". It is convenient to describe the silicate slag structure in terms of the network character of silicates-either the Oxygen to Silicon ratio (O/Si ratio) or the Non Bridging Oxygen (NBO).The effect of O/Si ratio (and temperature) on the viscosity of slags has been studied theoretically in this work. Data on composition and viscosities were taken from the literature and the trends have been analyzed in terms of Oxygen to Silicon ratio. Data on four different slag systems, consisting of 33 slags, covering a range of temperatures, have been used. In all cases, irrespective of the system and the temperature, the viscosity was found to decrease steadily with increasing Oxygen to Silicon ratio. This is due to the increased breaking of the silicate network. The suitability of this parameter for assessment of slags (viscosities) has been demonstrated. KEY WORDS: slags; viscosity; chemical composition; oxygen to silicon ratio; silicate structure.

Rare earth cobalt alloys have many special magnetic properties and can be used to prepare magnetic and magneto-optical components. The yttrium -cobalt intermetallic compounds are prepared by calciothermic reduction -diffusion (CRD) process at temperature of 1000ºC, under argon atmosphere. Yttrium oxide, metallic cobalt powder, metallic calcium are used as raw materials in this process. Calcium acts as the reductant, which is used to prepare the YCo5 magnetic material. XRD, SEM, EDAX and some thermodynamic valuation have been carried out on the products. The chemical reactions controlled by unreacted core model theory were studied.

The present work deals with thermodynamic modeling of oxide systems, in the context of slags and inclusions in steelmaking. The work has emphasis on oxides encountered during the production of tire - cord steel. Control of inclusion chemistry and variation in eutectic temperature and eutectic composition of MnOAl2O3- SiO2 slag system have been studied, using Thermo-CalcR software. Relatively low liquidus temperatures are obtained for ratio of MnO/SiO2 = 0.5 - 1.5 and Al2O3 content from 10 - 20 mass%. It has been observed that the addition of Alumina leads to further increase in the liquidus temperature. The stability of inclusions is analyzed in terms of free energy values of related slag systems; and an appropriate minimum of Gibbs free energy value of slag phase observed at around 50 ppm of Oxygen. The observations could not be verified using thermodynamic experiments, but have been compared with findings in the open literature