Tumbling melt granulation

The melt processes require at least a meltable material in the manufacture of the solid dosage form. This article intends to address the influence of meltable materials on the processes of melt pelletization, melt granulation, and tumbling melt granulation. Approaches to meet the processing attributes of the meltable materials for these melt agglomeration processes, via spray congealing, are discussed. 

Maejima, T. Osawa, T. Nakajima, K. Kobayashi, M. Preparation of spherical beads without any use of solvents by a novel tumbling melt granulation (TMG) method. Chem. Pharm. Bull. 1997, 45 (3), 518-524. 

Maejima T, Osawa T, Nakajima K, Kobayashi M. Effects of species of non-meltable and meltable materials and their physical properties on granulatability in tumbling melt granulation method. Chem Pharm Bull 1997 45 1833 1839. 

In other sulfur recovery operations, better control of product particle size is obtained. The molten sulfur is chilled on a steel belt to produce a roughly 0.5-in.-thick flake sulfur, or sprayed into water or even tumbled in drums to obtain granulated sulfur. Pelletized sulfur, similar in particle size range to the granulated variety, is also obtained when a melt is sprayed into the top of a tower to form droplets of molten sulfur which harden into shot-sized beads as they fall through a current of air. In this form, it is referred to as prills [20]. The narrow size range of particles of prilled sulfur, as well as the negligible dust content in this form, makes it more convenient to use. It normally commands a price premium. 

Fig. 6.6-30 shows cross sections of broken melt-coated fertilizer granules [B.97]. In this case, the cores of conventionally granulated (by tumble/growth agglomeration. Section 6.6.1) TSP (triple super phosphate) were melt-coated with sulfur to provide an additional nutrient for sulfur-deficient soils and/or obtain a slow-release fertilizer. Fig. 6.6-31 is the flow diagram that is used for this process. The centerpiece of the system is the so-called fluid drum granulator (FDG). 

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