About Us | Help Videos | Contact Us | Subscriptions

Soil Science Society of America Journal Abstract -

Bonding of Calcium and Potassium by Vermiculite and Kaolinite Clays as Affected by H-clay Addition1


This article in SSSAJ

  1. Vol. 39 No. 1, p. 48-50
    Received: May 24, 1974
    Accepted: Sept 9, 1974

Request Permissions

  1. A. S. Baweja and
  2. E. O. McLean2



The < 2 µm fraction of Libby vermiculite and Peerless kaolinite was separated and H-saturated by resin treatment. The H-clay suspensions were immediately saturated with either Ca or K by addition of the respective hydroxides. Six reciprocal Ca-K saturations of each clay were prepared by mixing the Ca- and K-clays in appropriate amounts. Increments of H-clay were added to lower the base saturation and thereby inactivate the pH-dependent charges. Radioisotopes, 45Ca and 86Rb, were used as tracers for Ca and K, respectively. Two-phase Donnan-type systems were prepared and equilibrated for 23 days. Radioactivity in both phases was then assayed and the amounts of Ca and K retained in the suspension phases of the two clay systems computed.

The pH-dependent fraction of the total CEC was 6.9 and 18.0% for vermiculite and kaolinite, respectively. Additions of H-clay increased the bonding of both Ca and K as indicated by greater clay-phase retention. However, maximum retention of the cations at all Ca-K saturation ratios did not occur when the amounts of H-clay added equaled the pH-dependent charge fraction of the clay as had occurred with bentonite and illite.

  Please view the pdf by using the Full Text (PDF) link under 'View' to the left.

Copyright © . Soil Science Society of America