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Nagashanmugama K.B.,JSW Steel Ltd | Srinivasanb K.,Anna University
Indian Journal of Chemical Technology | Year: 2011

An activated carbon is prepared from gingelly oil cake (GOC) by using sulphuric acid treatment and its Cr(VI) removal capacity is compared with that of commercial activated carbon (CAC). The effect of experimental parameters such as pH, initial concentration, contact time and adsorbents dose for Cr(VI) removal are studied. Langmuir, Freundlich and Temkin models are tested to describe the equilibrium isotherms. The maximum adsorption capacity of the adsorbents calculated from Langmuir isotherm is found to be 30.58 mg/g and 25.13 mg/g for sulphuric acid treated gingelly oil cake carbon (STGOC) and CAC respectively. R2 values show that both Langmuir and Freundlich models fit well to explain the adsorption phenomenon for STGOC and CAC. The kinetic data fits best to pseudo second-order model. FTIR analysis is used to obtain information on the nature of possible interaction between adsorbents and metal ions. SEM images confirmed the adsorption of Cr(VI) onto these adsorbents through morphological observations. Gibbs free energy values showed the feasibility of process and spontaneous nature of the adsorption. The adsorbents are also tested for the removal of Cr(VI) from chrome plating wastewater and found to remove Cr(VI) effectively. Source


Sah R.,JSW Steel Ltd | Dutta S.K.,M. S. University of Baroda
Transactions of the Indian Institute of Metals | Year: 2011

An attempt has been made to study the effect of coal quality on the reduction kinetics of iron ore-coal composite pellets under non-isothermal condition in inert atmosphere. During non-isothermal reduction of composite pellets, it is observed that (i) reduction rate of iron oxide increases with increasing temperature, (ii) reduction rate increases with increase in porosity of pellets and (iii) the computed values of activation energy (E) are lower during the initial stage of reduction (0.86-8.82 kJ mol -1) than those in the later stages of reduction (12.37-38.32 kJ mol -1). These values indicate that the initial stage reduction is controlled by gaseous diffusion mechanism and at final stage, mixed control reaction mechanism (i.e., both gaseous-diffusion and chemical reaction) is the rate controlling step. The present investigation aims at to assess the effect of Fe tot/C fix ratio in pellet, volatile matter in coal, and temperature on the reduction kinetics of iron ore-coal composite pellets using simultaneous thermogravimetric and differential thermal analyser (TG-DTA). © 2011 Indian Institute of Metals. Source


Nagashanmugam K.B.,JSW Steel Ltd | Srinivasan K.,Anna University
Indian Journal of Chemical Technology | Year: 2011

An activated carbon has been prepared from gingelly oil cake (GOC) by zinc chloride treatment and its Cr(VI) removal capacity is compared with that of commercial activated carbon (CAC). The effect of experimental parameters such as pH, initial concentration, contact time and adsorbents dose for Cr(VI) removal has been studied. Langmuir, Freundlich and Temkin models are tested to describe the equilibrium isotherms. The maximum adsorption capacity of the adsorbents calculated from Langmuir isotherm is found to be 62.5 mg/g and 25.13 mg/g for zinc chloride treated gingelly oil cake carbon (ZTGOC) and CAC respectively. R2 values show that both Langmuir and Freundlich models fit well to explain the adsorption phenomenon for ZTGOC and CAC. The kinetic data fits best to pseudo-second order model. FT-IR analysis has been used to obtain information on the nature of possible interaction between carbon adsorbents and metal ions. SEM images confirm the adsorption of Cr(VI) onto these adsorbents through morphological observations. Thermodynamic study shows the feasibility of process and spontaneous nature of the adsorption. The carbon adsorbents have also been tested for the removal of Cr(VI) from chrome plating wastewater and are found to remove Cr(VI) effectively. Source


Peranandhanthan M.,Indian Institute of Technology Kanpur | Peranandhanthan M.,JSW Steel Ltd | Mazumdar D.,Indian Institute of Technology Kanpur
ISIJ International | Year: 2010

Slag eye area in an axi-symmetrical water model of an argon stirred ladle has been measured through video photography as a function of gas flow rates, liquid depth, slag layer thickness and different types of upper phase liquid. It is shown that in addition to the principal operating parameters (i.e., gas flow rate, liquid depth and amount of slag), physical properties of the overlying liquid, particularly kinematic viscosity and density exert considerable influence on slag eye formation. Based on our experimental observation, it is shown that existing correlations do not constitute a sufficiently reliable basis for prediction of slag eye area in steelmaking ladles. Accordingly, a new correlation for slag eye area has been formulated through dimensional analysis embodying a large set of experimental data, derived from different combinations of bulk and upper phase liquids. Polynomial regression indicates that dimensionless slag eye area can be expressed in terms of Froude number, (Up 2/gH), density ratio, [RL/Δρ), and Reynolds number, (HUp/vs), via: (Aes/hH)=3.25(U P2/gH)1.28(ρL/Δρ) 055(νs/HUP)-005 in which, A es is the eye area, H is the slag layer thickness, h is the bulk liquid depth and UP is the average plume rise velocity. Experimental data reported by many investigators on aqueous as well as industrial scale ladle gas stirred ladles systems were subsequently applied to demonstrate the adequacy and appropriateness of the proposed correlation. Possible extrapolation of the correlation to eccentric gas injection and melt covered with a thick slag layer, which are more typical of ladle metallurgy steelmaking, is also examined. © 2010 ISIJ. Source


Barman S.C.,ArcelorMittal | Mrunmaya K.P.,JSW Steel Ltd | Ranjan M.,JSW Steel Ltd
Journal of Iron and Steel Research International | Year: 2011

Corex is an alternative ironmaking process and raceway is one of the important areas to maintain the stability of the furnace. The raceway parameters are well established for blast furnace operation. But for Corex process, it has not yet been established and optimized. Thus, a mathematical model was developed to determine various raceway parameters such as RAFT (raceway adiabatic flame temperature), tuyere gas velocity and kinetic energy. The model provides an idea about the raceway geometry, zone temperature and kinetic energy accumulated in tuyere gas. Besides, all the raceway parameters have been analyzed to find out their effects on the Corex process. It is found that RAFT influences the gasification reaction kinetics and higher RAFT generates more CO in reduction gas, which improves the metallisation degree of the DRI in shaft. It is also found that increased gas velocity and kinetic energy generate more fines and demand more coke to maintain char bed permeability. High coke rate increases the production cost and lowers the production of hot metal. © 2011 Central Iron and Steel Research Institute. Source

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