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kinetics of thermal decomposition of hydrated minerals associated with hematite ore in a fluidized bed reactor

International Journal of Minerals,Metallurgy and Materials 2017年第3期24卷 229-239页

作者： P.C. Beuria s.k. biswal B.k. Mishra G.G. Roy Institute of Minerals and Materials Technology Council of Scientific & Industrial Research Bhubaneswar-751013 India Indian Institute of Technology Kharagpur-721302 India

The kinetics of removal of loss on ignition(LOI) by thermal decomposition of hydrated minerals present in natural iron ores(i.e.,kaolinite,gibbsite,and goethite) was investigated in a laboratory-scale vertical fluidized bed reactor(FBR) using isothermal methods of kinetic *** in the FBR in batch processes were carried out at different temperatures(300 to 1200°C) and residence time(1 to 30 min) for four different iron ore samples with various LOIs(2.34wt% to 9.83wt%).The operating velocity was maintained in the range from 1.2 to 1.4 times the minimum fluidization velocity(Umf).We observed that,below a certain critical temperature,the FBR did not effectively reduce the LOI to a desired level even with increased residence *** results of this study indicate that the LOI level could be reduced by 90% within 1 min of residence time at 1100°*** kinetics for low-LOI samples(s two different reaction mechanisms in two temperature *** lower temperatures(300 to 700°C),the kinetics is characterized by a lower activation energy(diffusion-controlled physical moisture removal),followed by a higher activation energy(chemically controlled removal of LOI).In the case of high-LOI samples,three different kinetics mechanisms prevail at different temperature *** temperature up to 450°C,diffusion kinetics prevails(removal of physical moisture);at temperature from 450 to 650°C,chemical kinetics dominates during removal of matrix *** temperatures greater than 650°C,nucleation and growth begins to influence the rate of removal of LOI.

关键词： thermal decomposition fluidized beds kinetic analysis hydrated iron ore activation energy

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study on mixing and segregation behaviors in particulate fluidized bed system for mineral processing

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International Journal of Mining science and Technology 2015年第3期25卷 459-464页

作者： sahu s.N. sahu A.k. biswal s.k. Mineral Processing Department CSIR-Institute of Minerals and Materials Technology

In order to identify the mixing and segregation behaviors in a mineral processing operation, present study aimed on the hydrodynamics of solid–liquid fluidization. The study was carried out in a fluidization column with tapings at different height of the bed to collect the sample. The binary particles considered in this study are hematite(4800 kg/m3) and quartz(2600 kg/m3) at different size fractions in the range of average size 87×10^(-6)m to 400×10^(-6)m. It is observed that for various binary mixtures, both quartz and hematite particles share the equal composition by mass(50%) at a particular height of fluidized bed, referred as ‘‘locus point'' of mixing. study indicates that the mixing zone volume will increase for a continuous fluidized bed plant operation. It is observed that the number of locus points varies from 1 to 3 signifying their dependency on the size ratios of binary mixture. Whenever, the difference in terminal velocity between quartz and hematite particles approaches to zero, mixing is ***, the present study is extended to find the segregation index for the different size ratios of quartz and hematite particles. It is evident that depending on the size ratios, various regions such as complete segregation, partial mixing and complete mixing can be observed.

关键词： Liquid-solid fluidization Mixing segregation Locus point Mineral processing

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study on kinetics of thermal decomposition of low LOI goethetic hematite iron ore

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International Journal of Mining science and Technology 2017年第6期27卷 1031-1036页

作者： Beuria P.C. biswal s.k. Mishra B.k. Roy G.G. Mineral Processing Department CSIR–Institute of Minerals and Materials TechnologyBhubaneswar 751013India Indian Institute of Technology Kharagpur 721302India

In the present study, the kinetics of thermal decomposition of hydrated minerals associated in natural hematite iron ores has been investigated in a fixed bed system using isothermal methods of kinetic analysis. Hydrated minerals in these hematite iron ores are kaolinite, gibbsite and goethite, which contribute to the loss on ignition(LOI) during thermal decomposition. Experiments in fixed bed have been carried out at variable bed depth(16, 32, 48 and 64 mm),temperature(400-1200 ℃) and residence time(30,45, 60 and 75 min) for iron ore samples. It is observed that beyond a certain critical bed depth(16 mm), 100% removal of LOI is not found possible even at higher temperature and higher residence time. Most of the solid-state reactions of isothermal kinetic analysis have been used to analyze the reaction mechanism. The raw data are modified to yield fraction reacted "α" versus time and used for developing various forms of "α" functions.f(α) is the inverse of first derivative of g(α) with respect to α. The study demonstrates that decomposition of hydrated mineral in hematite follows the chemical *** estimated activation energy values in all the experimental situations are found to high, of the order of 60 kJ/mol, reinstating that the reactions are indeed controlled by moving phase boundary and random nucleation.

关键词： Loss on ignition Goethite kaolinite Gibbsite Roasting Pellet feed kinetic analysis

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A model for expansion ratio in liquid-solid fluidized beds

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Particuology 2013年第6期11卷 789-792页

作者： Alok Tripathy A.k.sahu s.k.biswal B.k.Mishra Council of scientific and Industrial Research Institute of Minerals and Materials Technology

Liquid-solid fluidized beds are used in mineral processing industries to separate particles based on parti- cle size, density, and shape. Understanding the expanded fluidized bed is vital for accurately assessing its performance. Expansion characteristics of the fluidized bed were studied by performing several experi- ments with iron ore, chromite, quartz, and coal samples. Using water as liquid medium, experiments were conducted to study the effects of particle size, particle density, and superficial velocity on fluidized bed expansion. The experimental data were utilized to develop an empirical mathematical model based on dimensional analysis to estimate the expansion ratio of the fluidized bed in terms of particle character- istics, operating and design parameters. The predicted expansion ratio obtained from the mathematical model is in good agreement with the experimental data.

关键词： Fluidization Bed expansion Mathematical modelling Dimensional analysis Particle processing Void fraction

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A numerical study of violent sloshing problems with modified MPs method

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Journal of Hydrodynamics 2017年第4期29卷 659-667页

作者： Debadatta Jena kishore Chandra biswal Department of Civil Engineering National Institute of Technology

A numerical study on violent liquid sloshing phenomenon in a partially filled rectangular container is carried out by using moving particle semi-implicit（MPs） method. The present study deals with the implementation of five modifications all together over the original MPs method. The modifications include improved source terms for pressure Poisson equation, special approximation technique for the representation of gradient differential operator, collective action of mixed free surface particle identification boundary conditions, effecting Neumann boundary condition on solving the PPE and fixing judiciously the parting distance among particles to prevent collision. The suitability of the kernel function used in the original MPs method along with these five modifications is investigated for violent sloshing problems. The present model ensures a good agreement between numerical results with the existing experimental observations. The model is successfully applied to a partially filled tank undergoing horizontal sinusoidal excitation to compute the sloshing wave amplitudes and pressure on tank walls. The assessment of dynamic behaviour manifested in terms of base shear, overturning moment and impact pressure load exerted on tank ceiling induced by violent sloshing motion using MPs method is not reported in the open literature and has been efficiently carried out in the present study.

关键词： sloshing particle method impact pressure base shear overturning moment

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seismic evaluation of frequency influence and resonant behavior for lead rubber bearing isolated rigid rectangular liquid tanks

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Earthquake Engineering and Engineering Vibration 2024年第4期23卷 973-994页

作者： Jyoti Ranjan Barik kishore Chandra biswal Department of Civil Engineering National Institute of Technology RourkelaOdisha 769008India

The seismic behavior of a partially filled rigid rectangular liquid tank is investigated under short-and longduration ground motions.A finite element model is developed to analyze the liquid domain by using four-noded quadrilateral *** competency of the model is verified with the available *** studies are conducted for the dynamic parameters of the base-isolated tank,using a lead rubber bearing to evaluate the optimum damping and time period of the *** application of base isolation has reduced the total and impulsive hydrodynamic components of pressure by 80 to 90 percent,and base shear by 15 to 95 percent,depending upon the frequency content and duration of the considered *** sloshing amplitude of the base-isolated tank is reduced by 18 to 94 percent for most of the short-duration earthquakes,while it is increased by 17 to 60 percent for the majority of the long-duration ***,resonance studies are carried out through a long-duration harmonic excitation to obtain the dynamic behavior of non-isolated and isolated tanks,using a nonlinear sloshing *** seismic responses of the base-isolated tank are obtained as higher when the excitation frequency matches the fundamental sloshing frequency rather than the isolator frequency.

关键词： lead rubber bearing frequency domain resonant inputs long-duration excitation

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Reduction behaviour of Odisha sands Complex,India ilmenite-coke composite pellets

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Journal of Central south University 2020年第6期27卷 1678-1690页

作者： D NAYAk N RAY N DAsH s s RATH s.k.biswal CsIR-Institute of Minerals&Materials Technology Bhubaneswar-751013OdishaIndia

Presently,ilmenite concentrates from Odisha sands Complex at Chhatrapur,India are utilized to produce TiO2 slag by direct smelting in an electric arc ***,the process involves the consumption of excess electrical energy and difficulty in handling the arc furnace due to frothing effects.A more efficient process of pre-reducing the ilmenite before smelting has been proposed in the present *** particular,studies have been undertaken on the reduction process of ilmenite-coke composite *** difference in the reduction behaviour of raw ilmenite and ilmenite-coke composite pellets has been established and compared with that of the pre-oxidized raw *** effects of various processing parameters like temperature,residence time,and reductant percentage on the metallization of composite pellets in a static bed have been *** of about 90%has been achieved at 1250°C for a reduction period of 360 min with a 4%coke ***,the reduced pellets have been characterized through chemical analysis,optical microscopy,field emission scanning electron microscopy and X-ray diffraction *** reduction behaviour of composite pellets has also been found better than that of pre-oxidized pellets indicating the former to be more efficient.

关键词： ilmenite composite pellet pre-oxidation reduction metallization

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A shake table investigation of dynamic behavior of pile supported bridges in liquefiable soil deposits

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Earthquake Engineering and Engineering Vibration 2021年第1期20卷 1-24页

作者： Piyush Mohanty Xu Dan suryakant biswal subhamoy Bhattacharya CsIR-Central Building Research Institute Roorkee247667India Fluor Ltd. 140 Pinehurst RoadFarnboroughGU147BFUK Institute of Engineering Mechanics China Earthquake AdministrationSanhe 065201China University of surrey GuildfordGU27XHUK

Bridges are a part of vital infrastructure,which should operate even after a disaster to keep emergency services *** have been numerous bridge failures during major past earthquakes due to *** other categories of failures,mid span collapse(without the failure of abutments)of pile supported bridges founded in liquefiable deposits are still observed even in most recent *** mechanism of collapse is attributed to the effects related to the differential elongation of natural period of the individual piers during liquefaction.A shake table investigation has been carried out in this study to verify mechanisms behind midspan collapse of pile supported bridges in liquefiable *** this investigation,a typical pile supported bridge is scaled down,and its foundations pass through the liquefiable loose sandy soil and rest in a dense gravel *** noise motions of increasing acceleration magnitude have been applied to initiate progressive liquefaction and to characterize the dynamic features of the *** has been found that as the liquefaction of the soil sets in,the natural frequency of individual bridge support is reduced,with the highest reduction occurring near the central *** a result,there is differential lateral displacement and bending moment demand on the *** has also been observed that for the central pile,the maximum bending moment in the pile will occur at a higher elevation,as compared to that of the interface of soils of varied stiffness,unlike the abutment *** practical implications of this research are also highlighted.

关键词： bridges midspan failure liquefaction bridge collapse earthquake pile shake table test natural frequency

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Artificial neural network approach to assess selective flocculation on hematite and kaolinite

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International Journal of Minerals,Metallurgy and Materials 2014年第7期21卷 637-646页

作者： Lopamudra Panda P.k.Banerjee surendra kumar biswal R.Venugopal N.R.Mandre R&D Tata steel Limited Institute of Minerals and Materials Technology(Council of scientific and Industrial Research) Department of Fuel & Minerals Engineering Indian School of Mines University

Because of the current depletion of high grade reserves, beneficiation of low grade ore, tailings produced and tailings stored in tailing ponds is needed to fulfill the market demand. selective flocculation is one alternative process that could be used for the beneficiation of ultra-fine material. This process has not been extensively used commercially because of its complex dependency on process parameters. In this paper, a selective flocculation process, using synthetic mixtures of hematite and kaolinite in different ratios, was attempted, and the ad-sorption mechanism was investigated by Fourier transform infrared （FTIR） spectroscopy. A three-layer artificial neural network （ANN） model （4？4？3） was used to predict the separation performance of the process in terms of grade, Fe recovery, and separation efficiency. The model values were in good agreement with experimental values.

关键词： hematite kaolinite flocculation artificial neural networks back propagation algorithm Fourier transform infrared spectroscopy separation efficiency

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Frequency dependent electrical properties of Na_(2)Pb_(2)R_(2)W_(2)Ti_(4)Nb_(4)O_(30)(R=Nd,sm)ceramics

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Journal of Advanced Ceramics 2014年第3期3卷 215-223页

作者： Lalatendu biswal Piyush RDAs Banarji BEHERA Department of Physics SOTKIIT UniversityBhubaneswar-751024OdishaIndia Department of Physics Veer Surendra Sai University of TechnologyBurla-768018SambalpurIndia school of Physics Sambalpur UniversityJyoti ViharBurla-768019OdishaIndia

In the present research work,frequency dependent electrical properties of tungsten bronze structured compounds Na2Pb2R2W2Ti4Nb4O30(R=Nd,sm)are reported.X-ray diffraction(XRD)study of polycrystalline ceramic samples confirms the formation of compounds with orthorhombic *** of frequency dependent electrical data in the framework of modulus and conductivity formalism suggests the presence of thermally activated relaxation process in the compounds,which show Arrhenius *** magnitudes of activation energies give the nature of the relaxing *** real and imaginary parts of complex modulus trace the depressed semicircle in complex plane,suggesting non-Debye type relaxation process in the *** power law behavior of admittance data is successfully modeled by introducing constant phase element(CPE)to the equivalent circuit.A large value of power law parameter(n)of CPE below ferroelectric transition temperature(Tc)is attributed to the cooperative response of the dipoles which is reduced above *** behavior is correlated with the frequency dependence of CPE,suggesting a physical meaning to *** frequency dependent AC conductivity at different temperatures follows Jonscher’s universal power *** and West formalism is used to estimate the hopping rate,activation enthalpy and charge carrier concentration in the materials.

关键词： ceramics electrical properties microstructure electrical conductivity

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