Evaluation of dispersibility of aqueous alumina suspension in presence of Darvan C

The effect of ammonium salt of polymethacrylic acid commercially known as Darvan C as a dispersant on stability of aqueous suspension of Al2O3 was investigated through sedimentation test, determination of wet and flow points, and measurement of streaming potential. The degree of dispersion estimated by the sedimentation test was correlated with particle surface charge, and the inflection point in streaming potential as a function of concentration. Good agreement was observed between dispersion characteristics and specific charge and inflection in streaming potential. The results also illustrate the applicability of wet point and flow point techniques for examining colloidal dispersions. A convenient and reliable method of rapidly measuring stability maxima with optimum dispersant concentration could be envisaged through measurement of surface charge by PCD and determining wet point and flow point.