The gas-liquid-solid fluidized bed has emerged in recent years as one of the most promising devices for three-phase operations. Such a device is of considerable industrial importance as evident from its wide applications in chemical, refining, petrochemical, biochemical processing, pharmaceutical and food industries. To explore this, a series of experiments were carried out for homogeneous well-mixed ternary mixtures of five different materials of varying compositions of three different particle sizes in a three-phase fluidized bed. The hydrodynamic characteristics determined included the bed pressure drop, bed fluctuation and bed expansion ratios. The dependence of these quantities on average particle diameter, mass fraction of the fines in the mixture, initial static bed height and material density has been discussed. Based on dimensional analysis and statistical analysis, correlations have been developed with the system parameters, viz., average particle diameter, initial static bed height, density of solid and superficial velocity of the fluidizing medium. Experimental values of bed pressure drop, bed fluctuation and bed expansion ratios have been found to agree well with the developed correlations. (C) 2012 Elsevier Ltd. All rights reserved.