STABILIZING OF AQUEOUS KAOLINITE SUSPENSIONS BY THERMAL VAPOR-PRESSURE SHOCK EXPLOSION TREATMENT

A new device for thermal vapor-pressure shock explosion (TSE) was cons tructed and the dispersion of three kaolinites (KGa-1, KGa-2 and S-5, well and poorly crystallized kaolinites from Georgia, USA and from Mak htesh Ramon, Israel, respectively) in aqueous suspensions investigated . In the new device, the clay suspension is heated in a sealed glass a mpoule at 300 degrees C for a few minutes and the water vapor pressure increases in the cell to approximate to 100 atm. At this stage the am poule is shattered in ice-cold water. This treatment stabilized suspen sions of KGa-1 and S-5 kaolinites. Particle-size distribution analysis showed that, by this treatment, smaller particles were obtained. A su spension of KGa-2 was not stabilized by this treatment although partic les became smaller. Suspensions of the three kaolinites peptized by so dium pyrophosphate, were compared with those obtained by TSE treatment . SEM images and XRD patterns of sedimented films showed that tactoids became thinner as a result of the TSE treatment. EDS analysis of Ti s uggested that the small particles, after the TSE treatment were formed from the disaggregation of the large aggregates. (C) 1998 Elsevier Sc ience B.V.