Effect of Boehmite Addition on Sintering Behaviour of Mullite Precursor Synthesized from Bauxite, Fly Ash and Precipitated Silica
1 Department of Chemical Technology, Ceramic Engineering Division, University of Technology, Calcutta University,Kolkata 700009/India
2 Department of Silpa-Sadana PSV Visva-Bharati University, Santiniketan 731236/India
Volume 8, Issue 4, Pages 85 - 92
Cost- effective mullite body was prepared by reaction sintering of natural bauxite, fly ash, a by-product in thermal power plants and precipitated silica. The study was designed to analyse the effect of synthetic boehmite as dopant on sintering behaviour of stoichiometric mullite body in terms of sintering temperature from 1400–1575 °C and dopant content varying from 0–1,2 mass-%. Sintered mullite was characterized by firing shrinkage, bulk density, apparent porosity, bending strength measurement, X-ray diffraction analysis and SEM studies. The result indicates that significant secondary mullitisation takes place at a lower temperature in presence of sintering aid. 1,2 % addition of boehmite generates remarkable thermo-mechanical properties in sintered body due to interlocked morphology with uniform distribution of the normal size mullite along with dispersion of fine corundum grains during sintering at 1575 °C.
bauxite, fly ash, mullite, boehmite, reaction sintering
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