Characterization and kinetics of alumina leaching from calcined Akpugo kaolinite for potential aluminum recovery

The kinetics study on alumina leaching from calcined Akpugo kaolinite was considered in this study. The shrinking core model and other relevant kinetic models were used for kinetic analysis of the leaching process. The leaching rate increases with increase in acid concentration, temperature, and sti...

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Main Authors: Ikechukwu A. Nnanwube, Okechukwu D. Onukwuli
Format: Article
Language:English
Published: Elsevier 2023-01-01
Series:South African Journal of Chemical Engineering
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S1026918522000877
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author Ikechukwu A. Nnanwube
Okechukwu D. Onukwuli
author_facet Ikechukwu A. Nnanwube
Okechukwu D. Onukwuli
author_sort Ikechukwu A. Nnanwube
collection DOAJ
description The kinetics study on alumina leaching from calcined Akpugo kaolinite was considered in this study. The shrinking core model and other relevant kinetic models were used for kinetic analysis of the leaching process. The leaching rate increases with increase in acid concentration, temperature, and stirring rate from 45.0 to 81.5% for acid concentrations of 2 M and 10 M, 44.9 – 83.6% for temperatures of 30 °C and 90 °C, and 45.7 – 82.7 % for stirring rates of 90 rpm and 540 rpm; while it decreases with increase in solid/liquid (S/L) ratio and particle diameter from 82.5 to 46.1% for S/L ratios of 20 g/L and 45 g/L and from 83.5 to 45.2% for particle sizes of <75 µm and <425 µm, respectively. The experimental data fitted into the diffusion through the product layer model while surface chemical reaction was established as the rate-determining step. The activation energy was estimated to be 26.40 kJ/mol while the frequency factor was estimated as 19.99 s−1. About 83.1% alumina was recovered from Akpugo kaolinite from the kinetic study while the overall kinetic constant was estimated as 4.253 s−1. Hence, the kinetic models considered were sufficient to analyze the experimental data.
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spelling doaj.art-40fba7cceb5040738bb3106a9515b34c2023-01-12T04:18:23ZengElsevierSouth African Journal of Chemical Engineering1026-91852023-01-01432437Characterization and kinetics of alumina leaching from calcined Akpugo kaolinite for potential aluminum recoveryIkechukwu A. Nnanwube0Okechukwu D. Onukwuli1Department of Chemical Engineering, Madonna University, Akpugo, Nigeria; Corresponding author at: Madonna University Nigeria, Akpugo campus., 75, Oriemba Market Square, Enugu, Nigeria.Department of Chemical Engineering, Nnamdi Azikiwe University, Awka, NigeriaThe kinetics study on alumina leaching from calcined Akpugo kaolinite was considered in this study. The shrinking core model and other relevant kinetic models were used for kinetic analysis of the leaching process. The leaching rate increases with increase in acid concentration, temperature, and stirring rate from 45.0 to 81.5% for acid concentrations of 2 M and 10 M, 44.9 – 83.6% for temperatures of 30 °C and 90 °C, and 45.7 – 82.7 % for stirring rates of 90 rpm and 540 rpm; while it decreases with increase in solid/liquid (S/L) ratio and particle diameter from 82.5 to 46.1% for S/L ratios of 20 g/L and 45 g/L and from 83.5 to 45.2% for particle sizes of <75 µm and <425 µm, respectively. The experimental data fitted into the diffusion through the product layer model while surface chemical reaction was established as the rate-determining step. The activation energy was estimated to be 26.40 kJ/mol while the frequency factor was estimated as 19.99 s−1. About 83.1% alumina was recovered from Akpugo kaolinite from the kinetic study while the overall kinetic constant was estimated as 4.253 s−1. Hence, the kinetic models considered were sufficient to analyze the experimental data.http://www.sciencedirect.com/science/article/pii/S1026918522000877AluminaKaoliniteNitric acidKineticsLeaching
spellingShingle Ikechukwu A. Nnanwube
Okechukwu D. Onukwuli
Characterization and kinetics of alumina leaching from calcined Akpugo kaolinite for potential aluminum recovery
South African Journal of Chemical Engineering
Alumina
Kaolinite
Nitric acid
Kinetics
Leaching
title Characterization and kinetics of alumina leaching from calcined Akpugo kaolinite for potential aluminum recovery
title_full Characterization and kinetics of alumina leaching from calcined Akpugo kaolinite for potential aluminum recovery
title_fullStr Characterization and kinetics of alumina leaching from calcined Akpugo kaolinite for potential aluminum recovery
title_full_unstemmed Characterization and kinetics of alumina leaching from calcined Akpugo kaolinite for potential aluminum recovery
title_short Characterization and kinetics of alumina leaching from calcined Akpugo kaolinite for potential aluminum recovery
title_sort characterization and kinetics of alumina leaching from calcined akpugo kaolinite for potential aluminum recovery
topic Alumina
Kaolinite
Nitric acid
Kinetics
Leaching
url http://www.sciencedirect.com/science/article/pii/S1026918522000877
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