The capability to predict the expansion characteristics of cohesive systems is still limited. A cohesive powder is fluidized by means of a second fluidizable solid and the possibility to describe the system with a model is evaluated. A generalized Richardson and Zaki correlation is tested and the form of the correlation is found to be valid as long as lower values of the exponential index are employed. The experimentation conducted in this work can be extended to substantiate preliminary findings and a research path to develop the work further is proposed. (C) 2006 Elsevier B.V. All rights reserved.