Anomalous aggregation behaviour of aluminium oxyhydroxides

✍ Scribed by James K. Beattie; John K. Cleaver; T.David Waite

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 497 KB
• Volume: 111
• Category: Article
• ISSN: 0927-7757
• DOI: 10.1016/0927-7757(95)03493-5

✦ Synopsis

The aggregation of alumina suspensions (~-alumina, boehmite and gibbsite) has been observed by light scattering as a function of the identity and concentration of added electrolyte, and of acidic pH. All the suspensions aggregated rapidly in the presence of less than 1 mM sulfate ion. The gibbsite suspension displayed a critical coagulation concentration of less than 50 mM chloride ion. The other three suspensions displayed anomalous stability in chloride solutions of concentrations greater than 0.1 M and only aggregated at higher chloride ion concentrations. This stability is not related to the pH and electrolyte dependence of the zeta potential.