Flotation and Flocculation Chemistry of Coals and Oxidized Coals: Technical Progress Report, March 15, 1988--June 15, 1988.

摘要

A novel technique based on the centrifugal force required to detach particles from the liquid/vapor interface has independently established the existence of surface energy distribution in coal. In addition film flotation of coal and polymer treated coal samples from various points on the partition curves shows that the observed heterogeneity and surface energy distribution are representative of single coal particles. Cationic and nonionic polyacrylamide adsorption on coal was studied along with film flotation of coal samples treated with these polymers. Surface energy distribution spectra constructed from cumulative partition curves obtained by film flotation reveals useful new information on possible conformations of the adsorbed polymers. Adsorption of PAM on coal occurs by hydrogen bonding and hydrophobic interaction leading to nitrated hydrocarbon and amide surfaces respectively. In the case of CAPM treated coal the surface comprises of 30% amide groups, 20% water, bound to adsorbed polymer and 10% to 15% nitrated hydrocarbons.35% of the surface of coal treated with NPAM consists of water of hydration and 20% nitrated hydrocarbon. The observed decrease in hydrophobicity is due to the water of hydration along with adsorbed polymer molecules. 11 refs., 7 figs. (ERA citation 13:046248)