Fraction 1. Exchangeable Metals. The low levels of Si, Al, S, and organic carbon found in leachate 1 (Table 11) imply that MgClz treatment does not affect silicates, sulfides, or organic matter.
Thermodynamic calculations indicate that Fe and Mn oxides should not be significantly solubilized at
pH 7.0, and concentrations of Fe in leachate 1 are indeed very low. The slight dissolution of carbonates (2-370) co:ild be reduced by shortening the leaching time.