| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 237560 | Powder Technology | 2011 | 11 Pages |
The purpose of this study was to investigate the effects of the different surface properties of powders on granular agglomeration in a high-shear mixer. Polyethylene glycol 6000 (PEG 6000) was used as the melting binder. Three different powders, with mean granule sizes of 75–150 μm were used as the raw materials: calcium carbonate, calcium sulfate, and sodium carbonate. The wetting properties of the raw materials were measured with a contact angle instrument. The results indicate that the speed at which the droplets sink into the powder bed and the contact angle of binder droplets on the powder surface play important roles in determining the progress of the agglomeration process. Several types of agglomeration were found: a slurry state, heterogeneous nucleation, snowballing, and induction growth behavior. Heterogeneous dispersion leads to induction behavior and subsequent growth, but a homogeneous dispersion leads to little or no nucleation and growth of agglomerate size.
Graphical abstractWe observed the Mean particle size distributions for the three different types of particles versus the number of impeller revolutions: (a) ratio of liquid to solid (Vliq/Vsol) was set to 0.3; (b) ratio of liquid to solid (Vliq/Vsol) was set to 0.4.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights►Heterogeneous dispersion leads to induction behavior and subsequent growth. ►Homogeneous dispersion leads to little or no nucleation and non-enlargement of size. ►Binder content affects the growth occurrence with heterogeneous dispersion. ►The interaction between binder and powders affects the growth behavior.
