An experimental study of sepiolite dissolution rates and mechanisms at 25 degrees C

摘要

The steady-state dissolution rates of sepiolite were measured as a function of pH from mixed-flow reactor experiments at 25 degrees C in both citrate bearing and citrate-free aqueous solutions. Dissolution at pH <= 5.5 and pH >= 9.18 was found to be non-stoichiometric, with relatively more Mg being released at low pH, while Si was preferentially released at high pH. The steady-state dissolution rate of sepiolite at 25 degrees C, based on Si release rates at far from equilibrium conditions, r(+) in mol/cm(2)/s at pH ( )>= 4.44 can be described by.