APPLICATION OF POLY(VINYL ALCOHOL) WITH AN ALKYL END GROUP CONTAININGANIONIC GROUPS TO COAL-WATER SLURRY AS A DISPERSANT

Anionic groups were introduced with copolymerization of corresponding vinyl monomers with vinyl acetate into poly(vinyl alcohol) (PVA) with an alkylthio end group. The polymers were investigated as a dispersant for coal-water slurry (CWM). Anionic groups such as sodium sulfonate and sodium carboxylate enhance remarkably the ability of PVA. with an alkylthio end group to disperse coal. Sodium polyacrylic acid with an alkyl end group also showed a good ability of dispersing coal. The ord er of the ability of dispersing coal in these polymeric dispersants al ong with sodium naphthalene sulfonate formaldehyde codensate (NSF) var ied by the kind of coal used. In cases of the polymeric dispersants, t he fluidity of coal in terms of dependence of viscosity on shear rate also varied, from dilatency to thixotropy, in accordance with coal use d. Impurities in coal as well as surface properties of coal particles might play important roles in the properties of CWM. (C) 1995 John Wil ey & Sons, Inc.