Surface-Chemical Studies on Graphite Suspensions using Inorganic Disperants

Electrokinetic and dispersion characteristics of graphite suspensions were studied in the absence and presence of varying concentrations of different inorganic dispersants, namely sodium silicate, sodium hexametaphosphate and sodium tripolyphosphate. The isoelectric point of graphite was found to be located at pH 2.3. From the zeta potential data obtained as a function of pH in the presence of varying concentrations of the dispersants, it was observed
that the phosphate based inorganic dispersants were more efficient in enhancing the electronegative character of zeta potential. Thus, better stability of the graphite suspension could be obtained using the phosphate based dispersants. The results of the dispersion tests corrobo-rated the zeta potential data. The electron microscopic studies indicated that the graphite particles obtained from the supernatant were finer than those in the settled portion.