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Induration of ilmenite pellets by oxidation is an essential step in the pelletization process since it decides the physical and metallurgical properties of the pellets. In this regard, the induration parameters such as temperature and roasting time have been optimized to obtain good quality ilmenite pellets made of concentrates obtained from low-grade ilmenite ores of Odisha, India. The oxidation temperature of 900 °C at a short roasting time of 15 min has been found suitable to achieve recommended requirements of various pellet properties such as cold compressive strength, porosity, metallization, tumble, and abrasion indices. X-ray diffraction and microstructural analysis indicate that the recrystallization of hematite in the oxidation process improves the mechanical strength of the pellets. In contrast, the formation of ferric pseudobrookite phase at 1000 °C and 1100 °C oxidation temperatures impairs the pellet strength. Unlabelled Image • The readiness of the ilmenite pellets for the reduction process was assessed through induration studies. • Different metallurgical properties were analyzed as a function of temperature and time. • Desirable pellet properties were attained at a temperature of 900 °C and a period of 15 min. • The phases changes occurred during induration were clarified using in-depth XRD, SEM, and EPMA analyses. • The oxidation mechanism of ilmenite pellets was correlated to the pellet consolidation. [ABSTRACT FROM AUTHOR]

This study focuses on the instability and fault analysis of transferred arc plasma, utilizing advanced signal processing methods. Transferred arc plasma systems find significant applications in various industries, including material processing, metallurgy, and waste management. However, the occurrence of instabilities and fault events can severely impact system performance and reliability. To address instabilities in arc plasma, various conditions were experimented. The operating parameters, such as arc voltage, arc current, acoustic, optical, and spectroscopic signals, were simultaneously recorded at a higher sampling rate. The proposed approach employs advanced signal processing methods, such as the Lyapunov exponent, fast-Fourier transform, short-time-Fourier transform, and power spectral density, to analyze the characteristics and instabilities of the transferred arc plasma process. By capturing and analyzing signals from multiple sensors, it becomes possible to identify deviations, irregularities, and fault patterns that arise during plasma operation. The outcomes of this research will have significant implications for the optimization and control of transferred arc plasma processes. By identifying and characterizing instabilities due to fault events at an early stage, system operators can take timely corrective actions, preventing potential damage and improving the overall system efficiency. [ABSTRACT FROM AUTHOR]

The reduction of iron ore using biomass-based reductants has opened up a new chapter because of its contribution to energy conservation and emission reduction. In this connection, the application of waste coconut shells (CS) as the reductant in the reduction roasting-magnetic separation of an iron ore overburden sample is explored. Characterization studies on the overburden having 49% Fe suggest that the sample is mostly a goethitic ore containing kaolinite as the major gangue mineral. A concentrate with 63.2% Fe at an iron recovery of 66.2% has been obtained from the low-intensity magnetic separation of the overburden roasted at a temperature of 800 °C, time of 60 min and a CS to feed ratio of 0.2. Characterization studies indicate the formation of magnetite and hematite under these optimum conditions, whereas roasting at a temperature of 900 °C and a reductant to feed ratio of 0.3 is found to form feebly magnetic phases like wustite, fayalite and complex iron aluminosilicates resulting in poor iron recovery. The thermo-gravimetric analysis studies explain the disintegration of the biomass and reduction of the iron ore thereby validating the reduction sequence as predicted using the characterization studies. Unlabelled Image • Novel application of coconut shell as a substitute to coal based reductants. • Iron recovery from iron ore overbudren using reduction roasting-magnetic separation. • Product with 63% Fe with an iron recovery of 66% from a feed of 49% Fe. • In-depth mineralogical characterization. [ABSTRACT FROM AUTHOR]