STABILIZATION OF AQUEOUS SUSPENSIONS OF PALYGORSKITE BY THERMAL VAPOR-PRESSURE SHOCK EXPLOSION (TSE) TREATMENT

A device was constructed in which a clay suspension is hermetically he ated at 220-degrees-C for a few minutes. This thermal treatment is acc ompanied by a pressure increase in the cell. Once the valve is opened, there is a fast release of the pressure inside the cell and a sudden evolution of the interparticle water. This shock leads to a quasi expl osion of the clay particle. This technique was named thermal vapour pr essure shock explosion (TSE). The effect of TSE treatment on the prope rties of palygorskite suspensions was investigated. Palygorskite suspe nsions in water are rather unstable and particles smaller than 3 mum i n size are not found before a TSE treatment. Stabilization of the susp ension can be obtained by TSE treatments and/or by using a dispersing agent such as pyrophosphate, or both. As a result of TSE treatments sm aller particles are obtained, the dispersiveness of the particles is i mproved and electrophoretic mobility is increased. Electron microscopy scans showed that the aggregates of needles which form the palygorski te fibres, disintegrate to separated thin needles as a result of the T SE treatment.