In order to enhance and control properties of aggregates and be able to predict the structure of final products, it is essential to establish a link between the product properties and the operating conditions. Experimental investigations have been conducted on agglomerates produced in spray fluidized beds using different primary materials (non-porous glass, porous ceramic) and HPMC (hydroxyl-propyl-methyl-cellulose) as the binder, under varying operating conditions, inlet gas temperature and binder concentration. X-ray mu-computed tomography, mu-CT, was utilized to evaluate the three dimensional micro-structure of the agglomerates and spatial distribution of each constituent primary particle in the aggregate. Values and the behavior of evaluated morphological descriptors are presented and discussed for different agglomerates. (C) 2014 Elsevier B.V. All rights reserved,