(275e) Spray Granulation of Nanopowders

Arto Gröhn and Karsten Wegner

Dry synthesis of nanoparticles with flame reactors can yield large quantities of nanopowders at rather low cost, as has been shown by pilot-scale flame spray pyrolysis (FSP, Bickmore et al., 1996; Wegner et al., 2011). Products recovered from the process at the bottom of the bag-house filter have a very low packing density and are easily fluidized. This can impose problems on nanoparticle handling with standard equipment and techniques and may result in the release of nanoparticles into the workspace.

Here, spray granulation of flame-made nanoparticles is investigated at the pilot- scale by the examples of silica and zirconia. The effect of process parameters such as slurry flow rate, solids fraction, and temperature on the characteristics of the spray granulator as well as the product granule characteristics is studied. Properties of the granules as well as the bulk powders are described with one emphasis being placed on aerosolization and dust formation.

References:

Bickmore, C.R., Waldner, K.F., Treadwell, D.R. and Laine, R.M. (1996), J. Am. Ceram. Soc. 79, 1419-1423.

Wegner, K., Schimmoeller, B., Thiebaut, B., Fernandez, C. and Rao, T.N. (2011), KONA 29, 251-265.