An improved class of universal collectors for the flotation of oxidized and/or low-rank coal

Ash minerals, including pyrite, can be separated from coal by flotation, pr imarily making use of the natural hydrophobicity of the carbonaceous matter in coal. However, to overcome the deleterious effect of oxygen functional groups on the coal surface, an organic collector is required. The most comm on industrial coal flotation collector is fuel oil, but the addition of oxy genated functional groups to the collector molecule markedly enhances the f lotation of lower rank and oxidized coals. This paper summarizes the result s of detailed study of the flotation response of two high-sulfur coals, Ill inois No. 6 coal and Pittsburgh No. 8, using different non-ionic oxygenated surfactants as the collector. The performance of these reagents is compare d with that of two oily collectors, namely dodecane and nonylbenzene, and m echanisms for the interaction of these compounds with coal are suggested. ( C) 2000 Elsevier Science B.V. All rights reserved.