Metal powders

Granulation of Metal Powders in Water

Freeze granulation can with advantage be used for granulation of various kinds of metal powders for the achievement of granules with homogenous distribution of metal particles and binder or pressing aid. However, large metal particles require normally an adaptation of the liquid medium in terms of viscosity to avoid critical settling during processing.

A specific advantage with freeze granulation regarding metals is that water in many cases can be used as the freeze drying ensures very limited oxidation versus conventional spray drying in air as no liquid water/air interface where oxidation take place is present.

There is no problem to process hard metal powders (WC/Co/Cu) in water with binder (PVA, PEG, PVP) with Freeze Granulation. Diamonds can be mixed in a slurry, but with larger sizes (>100 um) problems with segregation due to difference in density will increase.

As we use air atomization in Freeze Granulation, the size distribution of granules will be approximately 10-700 um, but can be adjusted by spray settings to the finer or coarser side.