THE ROLE OF AIR IN OIL AGGLOMERATION OF COAL AT A MODERATE SHEAR RATE

The agglomeration of an aqueous suspension of highly hydrophobic coal particles with heptane or hexadecane was investigated with a laborator y mixing unit equipped with a flat-blade, turbine agitator which produ ced a moderate shear rate. The ground sample of coal from the No. 2 ga s seam in West Virginia was subjected to agglomeration conditions both with and without air present in the closed mixing unit. Although comp act, nearly spherical agglomerates were produced both in the presence and absence of air, the rate of agglomeration was much greater, and la rger agglomerates were produced with a given amount of oil when air wa s present. Having air present also improved product quality and recove ry. The effect of air was greater with smaller amounts of oil than wit h larger amounts.