Viscosity changes during the slow coagulation of ferric hydroxide sol and the verification of the new equation, connecting the electrolyte concentration and time of coagulation

Abstract

The viscosity changes with time during the slow coagulation of ferric hydroxide sol was studied in presence of potassium chloride, potassium nitrate, sodium acetate, potassium oxalate and potassium phosphate as electrolytes. The points of inflection in the autocatalytic viscosity-time curves were taken to denote the same kinetic stage of coagulation (d 2 x/dt 2=0) brought about by adding different concentrations of the electrolyte. The reciprocal of the times corresponding to the inflection points were plotted against the respective concentrations of the electrolyte used. Straight lines were obtained in all cases showing the validity of the equation,C=a+m/n · 1/t, which is a particular case of the new Equation,C=a+m·1/t/n+1/t.