Torngranulering

Torngranulering is a term encountered in Nordic-language technical literature describing a form of granulation in which granules form primarily due to torsional (twisting) stresses and tearing of particles. The process emphasizes fragmentation of a powder or slurry under shear, followed by re-agglomeration of the fragments into cohesive granules, often with the aid of a binder, moisture, or interparticle friction. This approach differs from classic wet granulation, where granules form mainly through binder-mediated agglomeration, and from dry milling, where material is reduced in size without deliberate reassembly into larger units.

Mechanism and process conditions: under torsional loading, particles crack and fragment; fragments rearrange and adhere, yielding granules with irregular shapes and a broad size distribution. Equipment capable of inducing torques—such as mixer granulators, high-shear mixers, twin-screw kneaders, or rotating drums with twisting motion—can promote torngranulering. Moisture content, binder type, temperature, and residence time influence granule strength, friability, and final size distribution.

Applications and relevance: in pharmaceutical manufacturing, torngranulering may be used to improve flowability and compressibility when conventional granulation is challenging. In agricultural, ceramic, and catalyst production, the approach can facilitate formation of granules from powders with poor cohesion and may support tailored porosity or density.

Advantages and challenges: potential for efficient granule formation without extensive liquid binding and with flexible process tuning. However, control over particle size and shape can be more complex, energy input may be higher, and there is potential for equipment wear or over-granulation if process parameters are not precisely managed.

Terminology: the term is not universally standardized and may be used variably in Nordic sources; readers should consult specific process descriptions for precise definitions.