Effect of Potassium Sulfate on the Low-Temperature Formation of Alpha Alumina Platelets from Bayerite
The effect of potassium sulfate (K2SO4) on the phase transformation from bayerite [α-Al(OH)3] to α-Al2O3 has been studied. K2SO4 and -Al2O3 react and form K3Al(SO4)3. Decomposition of K3Al(SO4)3 can supply the α-Al2O3 seeds for heterogeneous nucleation, accelerate the transformation from the -Al2O3 to α-Al2O3, and lower the formation temperature of α-Al2O3. α-Al2O3 particles grow into hexagonal platelets in the presence of the liquid phase K3Al(SO4)3. The α-Al2O3 platelets obtained by a 900°C calcination of the bayerite and K2SO4 mixture have an average diameter of 1 m and an average diameter/thickness ratio of 10.
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Document Type: Research Article
Affiliations: Institute of Materials Science and Engineering, Lanzhou University, Lanzhou 730000, China
Publication date: 01 July 2010