Electrochemical modification of montmorillonitic content and its interplanar spacing in soft rock

Experimental studies were carried out to examine the electrochemical modification of montmorillonitic content and its interplanar spacing in soft rock. Test samples were wetted with CaCl2 electrolyte of different concentrations and then modified by direct current at various electric gradients. Measurements were taken of pH values at the anodic, cathodic, and intermediate zones of the modified clay samples. Furthermore, X–ray diffraction studies were carried out on specimens taken from anodic, cathodic, and intermediate zones for their mineralogical contents. The result obtained show with increasing CaCl2 electrolyte concentration and electric gradient, the montmorillonitic content in the three zones of the soft rock decreases. The newly formed minerals in these zones are calcite, gibbsite, and anhydrite. The montmorillonitic interplanar spacing in the soft rock is altered by electrochemical modification. The d001 spacing exponent increases with increasing CaCl2 electrolyte concentration and electric gradient.