Biomass & Bioenergy, Vol.5, No.6, 467-480, 1993
AGGLOMERATION CHARACTERISTICS OF ALUMINA SAND STRAW ASH MIXTURES AT ELEVATED-TEMPERATURES
The agglomeration characteristics of alumina sand-straw ash mixtures were investigated at various levels of ash content (0.0, 3.3, 27.8, and 43.5%) and temperature (620, 740, 850, and 1000-degrees-C) using scanning electron microscopy and energy dispersive X-ray analysis techniques. Agglomeration of alumina sand did not take place below the temperature of 850-degrees-C at all levels of ash content, but at the temperature of 850-degrees-C a weak bonding of particles was observed. However, at the temperature of 1000-degrees-C, the alumina particles agglomerated in the presence of straw ash at all levels of ash content as a layer of ash melt bonded the particles together. The temperature at which agglomeration occurred was within the range of the initial deformation (921-degrees-C) and softening (1054-degrees-C) temperatures of straw ash and the liquidus temperature of potash feldspar (990 +/- 20-degrees-C). The softening of straw ash and the formation of low melting temperature eutectic (potash feldspar) are two possible mechanisms for the agglomeration of alumina sand.
Keywords:AGGLOMERATION;ALUMINA;STRAW ASH;TEMPERATURE;SCANNING ELECTRON MICROSCOPY;X-RAY ANALYSIS;ASH FUSION