SLAG SURFACE TENSION MEASUREMENTS WITH CONSTRAINED SESSILE DROPS

Physical properties of slag are critical in the design and operation of refining technologies and slagging energy systems. The surface tension of slag impacts phenomena such as granulation, foaming, removal of solid inclusions, erosion of refractory and fouling. In this study, slag sessile drops formed on graphite, alumina and molybdenum substrates were compared. Use of graphite resulted in the largest contact angles, a desirable trait for surface tension measurements, but also led to reactions with the slag. Alumina and molybdenum were less reactive, but resulted in contact angles too small for measurements. When sessile drops were constrained by small substrate diameters to increase the apparent contact angle, surface tension measurements could be achieved with alumina and molybdenum substrates. The surface tension of coal slag was measured at up to 1600 degrees C in oxidizing and reducing gas atmospheres.