Preparation of free flowing fly ash granules containing multifunctional molecules

A new approach for the granulation of fly ash powder is studied. The fly ash dispersed in aqueous medium at pH>10 in the presence of multifunctional molecules such as methylol urea, triethanol amine, glycerol, glucose and pentaerythritol, was centrifugally separated, dried to a moisture content < 0.5 wt.% and then granulated by rotation granulation. Loosely packed powder agglomerates are produced by particle bridging by the multifunctional molecules through hydrogen bonding. The flow property of the powder is remarkably improved by the granulation process. The granules redisperse in aqueous medium, even after heating at 400°C, without any appreciable increase in primary particle size. The heated fly ash granules disintegrate to the primary particles and the particles disperse well in polyester resin by simple stirring.