Nonionic Surfactants as Collectors for the Flotation of Oxidized and/or Low-Rank Coal

Abstract

Ash minerals, including pyrite, can be separated from coal by flotation. Such separations are possible because of the natural hydrophobicity of the carbonaceous matter in coal, but an organic collector is required to overcome the deleterious effects of oxygen functional groups on the coal surface. This paper summarizes the flotation response of a high-sulfur coal, Illinois No.6 coal, using different nonionic oxygenated surfactants as the collector. The performance of these reagents is compared with that of two oily collectors, namely dodecane and nonylbenzene. One of the reagents gives comparable combustible matter recovery on an aged Illinois No.6 coal at around two percent of the amount of dodecane collector required. Mechanisms for the interaction of these compounds with coal are suggested.