Parameter Estimation of Kinetic Model Equations for Chemical Leaching of Coal

2014 ◽  
Vol 9 (2) ◽  
pp. 133-141 ◽  
Author(s):  
Santosh Kumar Sriramoju ◽  
A. Suresh ◽  
Pratik Swarup Dash ◽  
P. K. Banerjee
Keyword(s):  
Rate Equation ◽  
Kinetic Equations ◽  
Parametric Estimation ◽  
Core Model ◽  
Mineral Matter ◽  
Shrinking Core Model ◽  
Chemical Leaching ◽  
Leaching Process ◽  
Heterogeneous Rock ◽  
Shrinking Core

Abstract Coals are invariably associated with mineral matter, which makes it unsuitable for efficient utilisation. For difficult-to-wash coals, advanced coal beneficiation technologies like chemical leaching methods are under development. In this paper, kinetic equations using different methods have been evolved, and related parameters have been estimated, using the experimental results obtained during coal leaching process. As coal is a heterogeneous rock, three different methods namely (i) parametric estimation through rate equation, (ii) non-linear regression and (iii) parametric estimation through shrinking core model have been developed and validated to check the minimum level of permitted error tolerance. Experiments were designed, using full factorial design with three variables, which are sensitive to the process. Values of activation energy and k0 obtained, using the parametric estimation of rate equation and shrinking core model, are almost in the same range. The order of the reaction for silica and alumina is two, using rate equation method. The parametric data obtained from the polynomial regression method were compared with the actual data. The exponential polynomial provides a better fit for the chemical leaching process of coal.

scholarly journals Kinetic Study in Atmospheric Pressure Organic Acid Leaching: Shrinking Core Model versus Lump Model

Minerals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 613
Author(s):  
Kevin Cleary Wanta ◽  
Widi Astuti ◽  
Indra Perdana ◽  
Himawan Tri Bayu Murti Petrus
Keyword(s):  
Citric Acid ◽  
Acid Solution ◽  
Acid Leaching ◽  
Core Model ◽  
Shrinking Core Model ◽  
Citric Acid Solution ◽  
Lumped Model ◽  
Leaching Process ◽  
Shrinking Core ◽  
Simulation Results

The kinetics study has an essential role in the scale-up process because it illustrates the real phenomena of a process. This study aims to develop a mathematical model that can explain the mechanism of the leaching process of laterite ore using a low concentration of the citric acid solution and evaluate that model using the experimental data. As a raw material, this process used powder-shaped limonite laterite ores with a size of 125–150 µm. The leaching process is carried out using 0.1 M citric acid solution, F:S ratio of 1:20, and a leaching time of 2 h. The temperature parameter was varied at 303, 333, and 358 K. The experimental results showed that the higher the operating temperature, the higher the extracted nickel. The results of this experiment were used to evaluate the shrinking core kinetics model and the lumped model. The simulation results for both models show that the lumped model can provide better simulation results. Quantitatively, the percentage of errors from the shrinking core model is around 3.5 times greater than the percentage of errors from using the lumped model. This result shows that in this leaching process, the process mechanism that occurs involves the reactant diffusion step and the chemical reactions step; those steps run simultaneously.

scholarly journals A kinetics study of acetic acid on cobalt leaching of spent LIBs: Shrinking Core Model

2018 ◽  
Vol 154 ◽  
pp. 01033 ◽  
Author(s):  
Hendrik Setiawan ◽  
Himawan T.B.M. Petrus ◽  
Indra Perdana
Keyword(s):  
Acetic Acid ◽  
Acetic Acid Solution ◽  
Lithium Ion ◽  
Core Model ◽  
Shrinking Core Model ◽  
Solution Ph ◽  
Power Sources ◽  
Leaching Process ◽  
Necked Flask ◽  
Shrinking Core

Lithium-ion batteries (LIBs) are secondary rechargeable power sources which increasing production also leads to large amount of waste. In order to environmentally friendly reduce the waste, this work aimed to use acetic acid as a substitute leaching agent to leach Co metals which constitutes about 72.39% wt of the battery cathode. The leaching process was done in a three-necked-flask where calcined LIB cathode powder was mixed with acetic acid solution. The variables of the leaching process under investigation were solution pH, concentration of H2O2 in the solution, S/L ratio, temperature and reaction time. Experimental results showed that only temperature significantly influenced the leaching rate of Co. Since the process was exothermic, the maximum recovery decreased as temperature increased. Conventional shrinking core model that considers diffusion and irreversible surface reaction resistances was found not sufficient to predict the kinetics of the Co leaching with acetic acid. A more representative kinetics model that considers a reversible reaction of Co complex formation needs to be further developed.

scholarly journals Correction to An Unreacted Shrinking Core Model Serves for Predicting Combustion Rates of Organic Additives in Clay Bricks

2021 ◽  
Vol 35 (5) ◽  
pp. 4616-4616
Author(s):  
Florian Wesenauer ◽  
Christian Jordan ◽  
Mario Pichler ◽  
Aron Frei ◽  
Mudassar Azam ◽  
...  
Keyword(s):  
Core Model ◽  
Shrinking Core Model ◽  
Organic Additives ◽  
Clay Bricks ◽  
Shrinking Core

Mesopores inside electrode particles can change the Li-ion transport mechanism and diffusion-induced stress

2010 ◽  
Vol 25 (8) ◽  
pp. 1433-1440 ◽  
Author(s):  
Stephen J. Harris ◽  
Rutooj D. Deshpande ◽  
Yue Qi ◽  
Indrajit Dutta ◽  
Yang-Tse Cheng
Keyword(s):  
Core Model ◽  
Published Data ◽  
Shrinking Core Model ◽  
Stress Distributions ◽  
Active Electrode ◽  
Free Surfaces ◽  
Surface Cracking ◽  
Active Particles ◽  
Shrinking Core ◽  
And Diffusion

Following earlier work of Huggins and Nix [Ionics6, 57 (2000)], several recent theoretical studies have used the shrinking core model to predict intraparticle Li concentration profiles and associated stress fields. A goal of such efforts is to understand and predict particle fracture, which is sometimes observed in degraded electrodes. In this paper we present experimental data on LiCoO2 and graphite active particles, consistent with previously published data, showing the presence of numerous internal pores or cracks in both positive and negative active electrode particles. New calculations presented here show that the presence of free surfaces, from even small internal cracks or pores, both quantitatively and qualitatively alters the internal stress distributions such that particles are prone to internal cracking rather than to the surface cracking that had been predicted previously. Thus, the fracture strength of particles depends largely on the internal microstructure of particles, about which little is known, rather than on the intrinsic mechanical properties of the particle materials. The validity of the shrinking core model for explaining either stress maps or transport is questioned for particles with internal structure, which includes most, if not all, secondary electrode particles.

scholarly journals Macerals of Shengli Lignite in Inner Mongolia of China and Their Combustion Reactivity

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Ying Yue Teng ◽  
Yu Zhe Liu ◽  
Quan Sheng Liu ◽  
Chang Qing Li
Keyword(s):  
Activation Energy ◽  
Homogeneous Model ◽  
Optical Microscope ◽  
Core Model ◽  
Shrinking Core Model ◽  
Compact Structure ◽  
Shrinking Core ◽  
Combustion Reactivity ◽  
Combustion Processes ◽  
Kinetics Of

The macerals, including fusinitic coal containing 72.20% inertinite and xyloid coal containing 91.43% huminite, were separated from Shengli lignite using an optical microscope, and their combustion reactivity was examined by thermogravimetric analysis. Several combustion parameters, including ignition and burnout indices, were analyzed, and the combustion kinetics of the samples were calculated by regression. Fusinitic coal presented a porous structure, while xyloid coal presented a compact structure. The specific surface area of fusinitic coal was 2.5 times larger than that of xyloid coal, and the light-off temperature of the former was higher than that of the latter. However, the overall combustion reactivity of fusinitic coal was better than that of xyloid coal. The combustion processes of fusinitic and xyloid coals can be accurately described by both the homogeneous model and the shrinking core model. The features of xyloid coal agree with the shrinking core model when its conversion rate is 10%–90%. The activation energy of fusinitic coal during combustion can be divided into three phases, with the middle phase featuring the highest energy. The activation energy of xyloid coal is lower than that of fusinitic coal in the light-off phase, which may explain the low light-off temperature of this coal.

A hybrid peripheral fragmentation and shrinking-core model for fixed-bed biomass gasification

2020 ◽  
Vol 400 ◽  
pp. 124940
Author(s):  
Zhiyi Yao ◽  
Xin He ◽  
Qiang Hu ◽  
Wei Cheng ◽  
Haiping Yang ◽  
...  
Keyword(s):  
Fixed Bed ◽  
Biomass Gasification ◽  
Core Model ◽  
Shrinking Core Model ◽  
Shrinking Core
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