Surface Chemical Technology for Improved Wetting of Coal Dust

摘要

The wetting of coal dust by aqueous solutions of surface active agents (surfactants) has been studies. Thirty coals and typical surfactants were selected from typical classes of anionic, nonionic, and cationics in aqueous solutions was eliminated because of the inherent negative Zeta potential charge of the representative coals. The wetting of the coals was examined by column flow, contact angle, and settling rate measurements. Results indicated that both anionic and nonionic surfactants are to be considered viable for use; low critical micelle concentration values are also preferred for the surfactants. Study of native waters showed substantial variation in properties, i.e., pH, calcium ion concentration, and conductance. pH variations were also noted to affect the effectiveness of selected surfactants. Combinations of nonionic and anionic surfactants have, in certain instances, produced synergistic enhancement in the coal wetting superior to the effectiveness of each surfactant alone.