Study of the weathering of albite at room temperature and pressure with a fluidized bed reactor

A continuous reactor based on the fluidized bed technique was developed in order to study the kinetics and the mechanisms of the initial stages of weathering of albite. Simultaneous determination of Si, Al and Na and the observed low concentrations of the dissolved elements which were always at levels below saturation with respect to possible secondary precipitates, indicate that formation of a residual layer of a few tens of angstroms occurred at the surface of the feldspar. The composition of this layer, enriched in Si and/or Al, is strongly dependent on the pH of the aqueous solution. The formation of the layer is followed by the establishment of a quasi-steady state during which the dissolution of albite tends to become stoichiometric.