Alumina from coal wastes by the lime-soda sinter process

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Publication Type dissertation
School or College College of Mines & Earth Sciences
Department Metallurgical Engineering
Author Padilla, Rafael
Title Alumina from coal wastes by the lime-soda sinter process
Date 1984-08
Description The lime-soda sinter process for alumina extraction from domestic coal wastes has been investigated. The three main basic steps — sintering, leaching and desilication -- have been studied to obtain optimal operating conditions for the highest yield of alumina. The recovery of alumina up to 80% has been obtained by sintering coal waste mixtures having molar ratios of Na20/Al203 = 1.3 and Ca0/Si02 = 1.8 at 1200 - 1250°C for 20 - 30 min. The corresponding optimum conditions for water leaching of the sinters are temperatures of 60- 70°C for 30- 40 min. The sodium aluminate responds readily to desilication with CaCOH^ suspensions at room temperature. In the sintering stage, the kinetics of carbon combustion and sodium aluminate formation are also discussed. A mathematical model based on simultaneous mass and heat transport is formulated and applied to the carbon combustion process. The model predicts the combustion rate well. The kinetics data for sodium aluminate formation, obtained in the temperature range 1000 - 1250°C and atmospheric pressure, have been correlated using the nucleation and growth kinetics. An activation energy of 285.8 kJ/mol has been calculated for fine powder mixtures.
Type Text
Publisher University of Utah
Subject Sinter (Metallurgy); Aluminum
Dissertation Institution University of Utah
Dissertation Name PhD
Language eng
Relation is Version of Digital reproduction of “Alumina from coal wastes by the lime-soda sinter process” J. Willard Marriott Library Special Collections, TN 7.5 1984 P33
Rights Management ©Rafael Padilla. To comply with copyright, the file for this work may be restricted to The University of Utah campus libraries pending author permission.
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Identifier us-etd2,139890
Source Original: University of Utah J. Willard Marriott Library Special Collections
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ID 194122
setname ir_etd
Reference URL https://collections.lib.utah.edu/details?id=194122
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