Changes in charge charactistics of soils after treatment with 0.5M calcium chloride at pH 1.5

Abstract

The kinetics of the removal of iron, aluminium, and silicon from soils and clays in the pH range 0-3 have been studied using a number of oxides, clay minerals, and soils. At pH 1.5, aluminium is removed but little iron or silicon. An initial rapid rate of aluminium extraction is followed by a slower constant rate. The rapidly released aluminium is extracted in approximately 12 hr using 0.5M CaCl2 at pH 1.5.reatment of a range of soils and clays by this method reduced the positive charge developed at low pH very substantially but had little effect on the negative charge. It is suggested that the positive charges in the soils studied are mostly due to the 'active' aluminium oxides.