Oil agglomeration of oxidized coal

The effect of surface oxidation on the oil agglomeration characteristics of coal has not been well documented, although it is known that lower rank, hydrophilic coals are more difficult to agglomerate than higher rank, hydrophobic coals. In order to contribute to a better understanding of the effect of surface oxidation, the present investigation was undertaken. Upper Freeport bituminous coal from Pennsylvania was selected for the study because it is normally hydrophobic and readily agglomerated. A surface oxidation treatment was applied to this coal to see how it would affect the agglomeration characteristics of the material. In determining these characteristics, samples of oxidized and unoxidized coal fines were suspended in water and agglomerated with pure aliphatic hydrocarbons. Both the pH of the suspension and amount of added oil were varied, and in some cases various surfactants were added to the suspension. The electrokinetic properties of the coal particles and oil droplets were also determined to gain further insight. 12 refs., 10 figs.