Mazumdar D.,Indian Institute of Technology Kanpur |
Dhandapani P.,JSW Steel Ltd |
ISIJ International | Year: 2017
Experiments were carried out to measure mixing time and slag eye area in two different water model ladles with gas injection nozzle located at the mid bath radius position. Within the range of experimental conditions studied, the following correlations (in SI unit), for 95% mixing time and slag eye area, were found to work satisfactorily: (Equation Presented) In the above equations, Q is the gas flow rate (corrected to mean height and temperature of the liquid) (m3/s), L is the liquid depth (m), R is the vessel radius (m), ΔL is the slag layer thickness (m), υs is the kinematic viscosity (m2/s) of the upper phase, ρL is the bulk liquid density (kg/m3), τmix,95% is the mixing time (s), Aes is the slag eye area (m2), UP is the average plume rise velocity (m/s), g is the gravitational acceleration (m/s2) and Δρ is the metal-slag density differential (kg/m3). Based on the above and a set of four different bounds on (i) specific energy input rate, (ii) ladle aspect ratio, (iii) amount of liquid in ladle and (iv) slag layer thickness, a multi-objective, constrained optimization problem was formulated to investigate inert gas injection in steelmaking ladles. To this end, a Genetic Algorithm based optimisation procedure embodied in MATLAB™ was applied. Due to the conflicting nature of the objective functions, a Pareto optimal front, comprising many optimal solutions resulted from which the desirable range of operating parameters was identified. Present study has also indicated that desirable optimal operating conditions are likely to be a function of the location of the porous plug in a ladle. Finally, for the sake of validation, three arbitrarily chosen experimental conditions were evaluated against the relevant Pareto front and it is shown that the chosen conditions are, by and large, sub-optimal. © 2017 ISIJ.
News Article | April 17, 2017
--Nifty hovers around 9150; Indiabulls Real, Hindalco most activeThe 30-share BSE Sensex was up 27.14 points at 29,488.59 and the 50-share NSE Nifty gained 6.10 points at 9,156.90.Adani Group stocks were on buyers' radar as Adani Ports, Adani Enterprises, Adani Power and Adani Transmission gained 2-4 percent.HDFC, Reliance Industries and ICICI Bank continued to support the market whereas ITC, HDFC Bank and Infosys were under pressure.The rupee pared initial losses to rebound smartly by 10 paise to 64.31 against the American currency in late morning trade on fresh bouts of dollar selling by banks and exporters amidst bearish US dollar overseas.The rupee opened almost flat at 64.42 as against last Thursday's closing level of 64.41 per dollar at the Interbank Foreign Exchange (Forex) Market here today.The domestic currency hovered in a range of 64.44 to 64.2875 during morning deals before quoting at 64.31 per dollar at 1025hrs.Meanwhile, the dollar index was trading down by 0.16 per cent at 100.39 against a basket of six currencies.A truncated week ended the Thursday session with a loss of 52.65 points or 0.57 percent at 9,150.80 on the NSE. The index broke its last three sessions' narrow range of 90 points (9,160 – 9,250) on the downside and closed below 20-DMA for the first time in the last three month.This observation indicates weakness in the short-term and prices may see a further correction towards 8,950 – 9,000 levels. Thus, 9,250 – 9,275 remains strong resistance zone.· Bank of Baroda: BUY| Target Rs 191| Stop Loss 163| Return 8 percent· Engineers India: BUY| Target Rs 172| Stop Loss Rs142| Return 9.5 percent· HDFC: BUY| Target Rs 1575| Stop Loss Rs 1445| Return 6.7 percent· Bharti Airtel: SELL| Target Rs 297| Stop Loss Rs 355| Return 12.7 percent· JSW Steel: SELL| Target Rs 175| Stop Loss Rs 205| Return 8 percent
Lanjewar H.A.,JSW Steel Ltd |
Tripathi P.,JSW Steel Ltd
Journal of Materials Engineering and Performance | Year: 2016
Strengthening mechanisms dominant in non-equiaxed ferrite structures are not so familiar and well measured. In present study, non-equiaxed ferritic structures were generated and perceived to be strengthened by grain/crystal refinement, presence of varying substructures, solid solution strengthening, and textural hardening. A Nb-V microalloyed steel was modeled under various accelerated cooling and coiling temperature conditions in a thermo-mechanical simulator. Decrease in coiling temperature in conjunction with accelerated cooling resulted in non-equiaxed ferrite structures with array of phase morphologies. Intermediate transformation conditions produced increase in strength concurrent with observed smallness in crystallite size and high amount of microstrain in the matrix phase indicative of high dislocation densities and crystal imperfections. Increase in strength is partially attributed to solid solution and texture hardening owing to increase in (111) pole intensity in structure. © 2016 ASM International
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.
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.
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.
Prachethan Kumar P.,JSW Steel Ltd |
Raju B.S.L.,JSW Steel Ltd |
Ranjan M.,JSW Steel Ltd
Ironmaking and Steelmaking | Year: 2011
The Corex smelting reduction process was developed as an alternative to the blast furnace and consists of two reactors: the reduction shaft and the melter gasifier. Coal rather than coke is used for heat generation, production of reducing gases and to maintain adequate bed permeability; hence, coals have to meet certain physical, chemical and especially high temperature properties for stable process operation and high iron outputs. Statistical analysis was employed to investigate the influence of coal properties on Corex performance, and laboratory coal characterisation studies were correlated with plant performance. This paper details these coal characteristic studies and highlights the coal blend properties required for superior plant performance. © 2011 Institute of Materials, Minerals and Mining.
Umadevi T.,JSW Steel Ltd |
Brahmacharyulu A.,JSW Steel Ltd |
Sah R.,JSW Steel Ltd |
Mahapatra P.C.,JSW Steel Ltd
Ironmaking and Steelmaking | Year: 2014
From a sinter production point of view, it is important to optimise the sintering process with regard to both sinter quality and production rate. In sintering, airflow rate within the sinter bed decides the production rate and its physical and metallurgical properties. To study the influence of airflow rate (flame front speed) on sinter production and sinter quality, pot grate sintering experiments were conducted at sinter grate suction pressures ranging from 900 to 1700 mm water column over the sinter bed. During sintering, time-temperature data were recorded, and mineralogical studies were carried out. This study reveals that increase in sinter grate suction pressure through the sinter bed from 900 to 1700 mm water column significantly improved the sinter productivity from 34.37 to 48.90 t/m2/day; however, the physical and metallurgical properties of the sinter at higher suction pressure were not optimum with respect to blast furnace requirements. The maximum sinter productivity with desired physical and metallurgical properties was obtained at suction pressure 1300 mm water column. At this pressure, improvement in sinter quality was due to optimum firing temperature and enough retention time available for formation of mineral phases. At an airflow rate 1300 mm water column, sinter productivity was 41.0 t/m2/day, sinter strength (TI) was 73.10%, reduction degradation index was 25.0 and reducibility was 71.50%. © 2014 Institute of Materials, Minerals and Mining Published by Maney on behalf of the Institute.
Ravichandar D.,JSW Steel Ltd |
Balusamy T.,Anna University |
Nagashanmugam K.B.,JSW Steel Ltd
Applied Mechanics and Materials | Year: 2014
JSW Steel Limited, Salem Works (JSWSL), is an integrated steel plant, having a production capacity of 1.0 mtpa (million tons per annum) of high-grade automotive special steels. At JSWSL, hydrogen induced cracks and center unsoundness contribute more to UT (Ultrasonic testing) rejections in chrome-molybdenum (Cr-Mo) and high manganese grade steels. Hydrogen induced cracks was controlled by increasing argon flow rate from 3-4 Nm3 to 7-9 Nm3 during vacuum degassing. Vigorous purging led to a reduction in hydrogen levels from around 2 ppm (parts per million) to less than 1.5 ppm. Center unsoundness was controlled through optimising superheats in tundish. Data of trial heats revealed that, UT rejections were more in heats cast with superheat levels more than 35°C. Based on the data obtained from trial heats superheat was optimised to 25-35°C for both Cr-Mo and high manganese steels. The present paper discusses the measures taken to reduce UT rejections in these grades. © (2014) Trans Tech Publications, Switzerland.
Umadevi T.,JSW Steel Ltd |
Sah R.,JSW Steel Ltd |
Mahapatra P.C.,JSW Steel Ltd
Transactions of the Institutions of Mining and Metallurgy, Section C: Mineral Processing and Extractive Metallurgy | Year: 2014
Iron ore sinter, constituting a major proportion of blast furnace burden, significantly impacts the blast furnace performance. The chemical composition of iron ore fines, particularly alumina, sinter basicity and sinter MgO together with the thermal conditions that sinter blends are subjected to play an important role in the formation of mineral phases in sinter. To increase the sinter proportion (70-80%) in blast furnace, lowering of CaO in sinter mix is a vital parameter to balance the flux supply without affecting the slag volume and productivity. At present, the alumina content in the sinter grade iron ore fines at JSW Steel varies from 4 to 6%. The quality of iron ore presently being used calls for extensive investigations to produce low basicity sinter with high alumina iron ore. Studies have been carried out on low and high alumina iron ore fines to know the influence of sinter basicity and fuel (coke breeze) addition on sinter mineralogy, properties and productivity. It is found that with increase in sinter basicity, sinter productivity and reduction degradation index (RDI) decreased and tumbler index (TI) increased for both low and high alumina sinter at coke breeze rate of 65 kg t-1 of sinter. The low alumina sinter showed higher productivity and strength, and lower RDI due to the presence of higher silico ferrites of calcium and aluminium (SFCA) and magnetite phase, and lower pore phase as compared to high alumina iron ore sinter. The sinter productivity decreased and physical and metallurgical properties improved with increase in coke breeze addition by increasing the sinter basicity for high alumina sinter. © 2014 Institute of Materials, Minerals and Mining and The AusIMM.