De-agglomeration of hydrophobic and hydrophilic silica nano-powders in a high shear mixer

✍ Scribed by P. Ding; M.G. Orwa; A.W. Pacek

• Publisher: Elsevier Science
• Year: 2009
• Tongue: English
• Weight: 753 KB
• Volume: 195
• Category: Article
• ISSN: 0032-5910
• DOI: 10.1016/j.powtec.2009.06.003

✦ Synopsis

The effect of energy density, pH and solid concentration on kinetics of de-agglomeration of hydrophobic silica nano-powder in a high shear mixer and on the rheology of resulting suspensions was investigated and compared with de-agglomeration kinetics and rheology of the suspension of hydrophilic silica nano-powder. In both types of nano-powders large aggregates were broken by fracture and erosion. In hydrophobic nanopowder erosion was more pronounced whilst in hydrophilic nano-powder erosion followed initial fracture of large aggregates. At sufficiently high energy input both hydrophobic and hydrophilic aggregates were broken into nano-aggregates but, even at the highest energy input, those nano-aggregates could not have been broken into single nano-particles. Rheology of the suspensions of hydrophobic nano-aggregates strongly depends on pH and on solid concentration whilst rheology of suspensions of hydrophilic nano-powder is rather weakly dependent on those parameters.