The interaction of soluble salt particles in their saturated brines collector colloids by heterocoagulation. Experimental flois of interest from both a fundamental and practical perspective. tation results confirm this surface charge / collector colloid The state of dispersion/aggregation of alkali halide particles as adsorption model for a variety of soluble salt flotation determined by optical microscopy has been described based on systems including alkali halides, double salts, and alkali nonequilibrium electrokinetic measurements for alkali halides.
oxyanions ( 9 -11 ) .
These results indicate that the sign of the surface charge has a
Importantly it has been shown that the surface charge develsignificant effect on the extent of particle dispersion/aggregation.
oped by these alkali halide particles in saturated brines influ-
Atomic force microscopy (AFM) is now being used to directly
ences the stability of such particulate suspensions and the extent measure the interaction forces responsible for the stability of these alkali halide aggregates observed in optical microscopy studies. of particle interactions (12). DLVO theory is only of limited These experimental results can be explained based on the interfautility in describing suspension stability (13, 14). This is especial polar interaction theory. In this regard the nature of such cially true at high ionic strengths such as the case for soluble particle interaction forces at high ionic strengths is examined to salt particulate suspensions. The extent of particle interaction improve our understanding of these systems. ᭧ 1997 Academic Press has been studied by optical microscopy which clearly shows that Key Words: forces between dissimilar surfaces; high ionic when oppositely charged alkali halide particles are examined as strength; alkali halides; hydration forces; interfacial forces; acida binary mixture, significant aggregation occurs relative to the base interactions; surface charge; atomic force microscopy.
behavior of the individual salt particles at the same size and particle concentration, in which case they tend to remain dispersed (12,15). The photographs presented in Fig. 1 show the