Figure 1: Aqueous concentrations of elements released during experimental aluminization process in acidic conditions.

Aqueous Ca (circles) and Si (triangles) concentrations are shown as cumulative moles of elements (for 200 mg of vermiculite sample) in the output solutions from 0 to 1055 h (a). Aqueous concentrations of Mg (diamonds) and Al (squares) elements released into solution are given as normalized values relative to the dissolved Si contents, (b,c), respectively. The data obtained in this study (solid symbols) are compared to the analysis reported recently35 for the same material, setup and conditions (open symbols). In (a), the horizontal solid line indicates the cation exchange capacity of the material, whereas for (b,c) the horizontal lines represent dissolution stoichiometry values for Mg and Al. The top of the figure lists the different concomitant processes (dissolution, cation exchange and aluminium fixation) occurring during weathering of vermiculite.