KINETICS OF CALCIUM MAGNESIUM EXCHANGE ON SOIL USING A STIRRED-FLOW REACTION CHAMBER

A stirred-flow method that uses a constantly stirred reaction chamber with constant, steady inflow of the reactant solution and outflow of reactants and products was tested. The measureable reaction rates using the stirred-flow method were estimated using a simple empirical equation that allowed the use of the reaction half-time (t1/2) to describe reaction rates. Values of t1/2 of 3 min and greater were detectable while a 0.3 min t1/2 was not detectable under the experimental conditions. Calcium-Mg exchange on Nordya sand loam soil from Israel was investigated. Measured effluent concentrations were compared with values calculated assuming no adsorption preference for Ca or Mg, and assuming local equilibrium between adsorbed and solution phases prevailed. Study results are discussed