Al-Monohydrate (Boehmite) to Al-Trihydrate(Bayerite/Gibbsite) Transformation During High-Energy Milling

Alex, T C and Kailath, A J and Kumar, Rakesh (2020) Al-Monohydrate (Boehmite) to Al-Trihydrate(Bayerite/Gibbsite) Transformation During High-Energy Milling. Metallurgical and Materials Transactions B, Online (IF-1.874). pp. 1-9.

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Abstract

The specific focus of this study is on the boehmite–water interaction during attrition milling of a boehmite prepared by thermal dehydroxylation of gibbsite. Various characterization studies confirm the formation of a new phase, bayerite (an Al-trihydroxide polymorph) during milling of boehmite with water as the dispersant. Bayerite is a more stable (thermodynamically) phase than boehmite. By forming bayerite, the free energy of the interacting system (consisting of disordered metastable boehmite and water) gets reduced. Such a transformation is of relevance in the digestion of Al-monohydrates in the Bayer process of alumina production. Furthermore, the presence of water during attrition milling itself is essential for the transformation. Bayerite does not form during attrition milling of the same boehmite in ethyl alcohol media and subsequent soaking in water up to 36 hours. Therefore, bayerite formation does not depend solely on structural degradation.

Item Type:Article
Official URL/DOI:https://link.springer.com/article/10.1007%2Fs11663...
Uncontrolled Keywords:gibbsite; Bayerite; boehmite; Al-monohydrates; attrition milling
Divisions:Metal Extraction and Forming
ID Code:8077
Deposited By:Dr. A K Sahu
Deposited On:28 Jan 2020 16:50
Last Modified:28 Jan 2020 16:50
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