PREDICTION OF THE PRODUCT SIZE IN THE AGGLOMERATION OF COAL PARTICLES IN A WATER OIL EMULSION

The size of the final product of the agglomeration of coal particles in a water-oil emulsion is calculated with the assumption that the decisive factor in the formation of agglomerates is the interaction between the surface tension force of the bridging liquid and centrifugal force due to rotation of agglomerate subjected to the gradient velocity of the surrounding liquid phase. Influence of the amount of agglomerant and of the initial size of agglomerated coal on the final size were determined from the experimental data in literature. A theoretical formula and an experimentally calibrated formula for the diameter of the final product are derived. These formulae show how this diameter is affected by a solid particle density, interfacial (oil/water) tension coefficient, amount of oil, initial solid particle size, impeller rotation speed and by the ratio of the gap between impeller end and internal baffle edge to the impeller radius. It is suggested that in the presence of excess agglomerant the final agglomerate diameter is controlled by the hydrodynamic drag and surface tension interaction.