ELECTROKINETIC SOLID-LIQUID SEPARATION OF AN ULTRAFINE KIMBERLITE SUSPENSION.
Electrokinetic dewatering of kimberlite slime under constant direct currents of 0. 5 to 2 A and dewatering under constant applied potentials of 16. 5 to 46. 5 V are considered. The combined effects of electrophoresis and the additon of 8. 3 multiplied by 10** minus **3 M Mg**2** plus ions on the one hand, and 1 to 10 p. p. m. of the anionic polyacrylamide flocculant Praestol 2935 on the other, were investigated. During electrophoretic dewatering, the zeta potential of the kimberlite particles did not change significantly whereas the pH and temperature showed increases with time. The addition of Praestol 2935 enhanced the settling of the sludge bed owing to the additional effect of flocculation. The addition of electrolyte Mg (ClO//4)//2 retarded the separation process, partly as a result of gel formation in the slurry. In general, electro-osmotic dewatering seemed to be more energy-efficient than electrophoretic dewatering.