Page 254 - Introduction to Colloid and Surface Chemistry
P. 254

Colloid stability  243

        4.  Paints. The particles in pigmented paints are often large enough to
           settle  even  when  peptised;  therefore,  it  is  desirable  that  they
           should be aggregated  to a certain extent to facilitate redispersion.

          Some  other  practical  situations  where  particle  aggregation  is
        important include the precipitation of colloidal mud at the mouth of a
        river  due  to  the  salinity  of  the  sea-water  exceeding  the  critical
        coagulation  concentration,  land  (e.g.  mountainside) stability, building
        and road foundations, the retention of a porous structure in filtration,
                         117
        mineral processing  and paper making. Control  of particle aggrega-
        tion  is also  of primary importance  in  adhesives,  inks, Pharmaceuticals,
        cosmetics,  foodstuffs  and  lubricants.
   249   250   251   252   253   254   255   256   257   258   259