ELECTROOSMOTIC DEWATERING (EOD) OF CLAYS AND SUSPENSIONS: COMPONENTS OF VOLTAGE IN AN ELECTROOSMOTIC CELL

ABSTRACT

In the electroosmotic dewatering (EOD) of clays, suspensions and fines, a continuous or interrupted DC voltage, V, is applied between the anode and the cathode. In the previous literature on this subject the components of V have not been completely clarified.

Following a brief outline of the EOD that emphasizes the central role of the electrochemical double layer, we provide an analysis of the components of V, Three case are distinguished

(1)Threshold voltage V-n, for initiating the EOD and its connection to the so-called open-circuit voltage;

(2)EOD at very low voltages viz. around IV;

(3)EOD at very high rates for prolonged times where electrodes such as A𝓁 can form barrier oxides and some “caking” is also observed near the a node, This attempt to define the components of V under different conditions of EOD is aimed to identify parameters and processes that arc involved in the effect of V on EOD; RT for example, it is generally not recognized that —pH can form a significant part of V F under some conditions of EOD