Effect of Microwave Roasting on Aluminum Extraction from Diasporic Bauxite-Sodium Carbonate-Calcium Hydroxide Mixtures

The effect of microwave roasting on aluminum extraction from mixtures of diasporic bauxite with sodium carbonate and calcium hydroxide has been studied. The phase constitution and leaching performance of the clinkers were studied under different roasting conditions. Dielectric and thermal investigat...

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Bibliographic Details
Published in:JOM (1989) 2019-02, Vol.71 (2), p.831-837
Main Authors: Le, Thiquynhxuan, Ju, Shaohua, Ravindra, A. V., Li, Xiteng, Wang, Qi
Format: Article
Language:English
Subjects:
Alumina
Aluminum
Aluminum oxide
Bauxite
Bayer process
Calcium aluminate
Calcium aluminum silicates
Calcium carbonate
Chemistry/Food Science
Clinker
Constitution
Diaspora
Dielectric properties
Diffraction patterns
Earth Sciences
Energy
Energy consumption
Engineering
Environment
Heat
Leaching
Microwave absorption
Microwave heating
Physics
Roasting
Scanning electron microscopy
Silicon
Sintering
Slaked lime
Slurries
Sodium aluminate
Sodium carbonate
Technical Article
Temperature
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Summary:The effect of microwave roasting on aluminum extraction from mixtures of diasporic bauxite with sodium carbonate and calcium hydroxide has been studied. The phase constitution and leaching performance of the clinkers were studied under different roasting conditions. Dielectric and thermal investigations on raw slurry obtained from the mix revealed prominent microwave absorption characteristics. X-ray diffraction patterns established significant promotion of NaAlO 2 phase. In the microwave field, the aluminum (Al)-bearing minerals, viz. AlOOH and Al 2 O 3 , reacted with Ca(OH) 2 to form calcium aluminate and calcium aluminum silicate phases at rather low temperature in short time. Furthermore, increasing the temperature and time promoted the reactions of AlOOH and Al 2 O 3 with Na 2 CO 3 to form NaAlO 2 , resulting in high Al leaching rates. Remarkably, the Al extraction of the clinker microwave roasted at 800°C for 45 min was 82.24%, while the leaching rates of Na and Si were 90.2% and 8.4%, respectively.
ISSN:1047-4838
1543-1851
DOI:10.1007/s11837-018-3263-8