Pressing of powders

Pressing is the dominating shaping technique for ceramics and powder metals. Submicron and/or composite powders require adequate preparation to achieve a pressing performance that ensures dense compaction into a homogeneous state.

Conventional powder granulation methods (spray drying, sieve granulation etc) show drawbacks. Migration phenomena cause inhomogeneities and hard granules that do not disintegrate properly during pressing.

The preparation of a powder suspension by applying colloidal processing combined with sufficient mechanical treatment provides optimal homogeneity

  • can be preserved by spray freezing and subsequent freeze drying resulting in

Homogeneous powder granules with superior performance made by Freeze Granulation.

Granule homogeneity

Migration and segregation of the constituents that is common in other granulating processes such as spray drying is avoided in Freeze Granulation. By instant freezing of small droplets critical ice crystal growth is avoided. The freeze drying where the liquid medium is sublimated ensures homogeneity preservation, limited oxidation and soft bonds within the granules. This provides the best possible condition for any subsequent processing such as easy pressing to homogenous compacts, easy re-dispersing in a liquid, sintering of catalytic particles, dosage processes etc.