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Activation of kaolin with minimum solvent consumption by microwave heating

R. Z. Al Bakain, Y. S. Al-Degs, A. A. Issa, S. Abdul Jawad, K. A. Abu Safieh and M. A. Al-Ghouti
Activation of kaolin with minimum solvent consumption by microwave heating
Clay Minerals (December 2014) 49 (5): 667-681


A kaolin clay was activated with 1.0 M H (sub 2) SO (sub 4) solution at minimum liquid to solid ratio (L/S) using microwave heating. The optimum experimental conditions for activation were L/S ratio 3.0 mL 1 M H (sub 2) SO (sub 4) per gram kaolin, microwave input power 500-600 W, and heating time 5-10 min. Activation at L/S <3.0 mL/g using 1.0 M H (sub 2) SO (sub 4) was not efficient, indicating the influence of solvent for absorbing microwaves more intensively and thus improving activation. Significant physicochemical changes were observed by the proposed procedure with smaller volumes of activator compared to the conventional heating method. Microwave input power and heating time have a strong influence on the quality of the final material; activation at high input power (>700 W) and longer heating times (>10 min.) are not recommended since they cause dissolution of kaolinite structure. Microwave-heated kaolin manifested better adsorption for tartrazine dye due to improvements in textural and chemical properties of kaolinite. Moreover, irradiation of used kaolinite has significantly improved dye desorption, increasing the importance of microwaves in regeneration/recycling studies. Detailed dielectric measurements of kaolin-acid mixtures recorded at frequencies much lower than 2.45 GHz revealed that absorption of radiation is highly dependent on the activator solution in the mixture. For 3.0 mL/g mixtures, high dielectric constant epsilon ' 5223, dielectric loss factor epsilon " 5083, tangent loss tan delta 1.30, penetration depth dp 0.57 cm at (10 (super 3) Hz), and AC-conductivity sigma 0.032 Omega m (super -1) were determined at 10 (super 5) Hz. Filling the pores of kaolin by acid solution increased the microwave absorption and hence de-alumination of kaolinite.

ISSN: 0009-8558
EISSN: 1471-8030
Serial Title: Clay Minerals
Serial Volume: 49
Serial Issue: 5
Title: Activation of kaolin with minimum solvent consumption by microwave heating
Affiliation: University of Jordan, Department of Chemistry, Amman, Jordan
Pages: 667-681
Published: 201412
Text Language: English
Publisher: Mineralogical Society, London, United Kingdom
References: 54
Accession Number: 2015-013833
Categories: Geochemistry of rocks, soils, and sedimentsSedimentary petrology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 3 tables
Secondary Affiliation: Hashemite University, JOR, JordanQatar University, QAT, Qatar
Country of Publication: United Kingdom
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Abstract, Copyright, Mineralogical Society of Great Britain and Ireland. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 201507
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