A sedimentation study to optimize the dispersion of alumina nanoparticles in water

摘要

Sedimentation studies have been earned out to optimize the dispersion conditions of aqueous alumina nanopowder suspensions with or without dispersants (ammonium salt of polymethacrylic acid or rhamnolipids at 15 percent). Different dispersant dosages, solid loadings, pulp densities and pH values were examined. The isoelectric point (IEP) of the alumina nanopowder was found to be pH_(iep)= 9.2. The experiments revealed that the polymethacrylic acid was more effective as dispersant than rhamnolipids in a wide range of pH at all solid-loading conditions tested. Optimum dispersant dosages for polymethacrylic acid and rhamnolipids to achieve maximum stability of alumina nanodispersion at iso-electric point were found to be 9.25 mg/g and 57.75 mg/g solids, respectively.