Mineral Surfaces. Minerals which are precipitated can also interact with other molecules and ions at the surface Attraction between a particular mineral surface and an ion or molecule due to: Electrostatic interaction (unlike charges attract) Hydrophobic/hydrophilic interactions
Where J is the flux (concentration area-1 time-1), D is the diffusion coefficient (area-1 time-1), C is concentration and t is time.
Where Rd is the diffusion rate (mass volume-1 time-1), D is the diffusion coefficient (cm2/sec), r is porosity, A is the surface area of the dissolving crystals per volume solution, Cs is the equilibrium concentration of ion in question, C is concentration, and r is spherical radius of dissolving crystals
pHZero-order mineral dissolution kinetics
where A is the surface area and k is the rate constant (mol cm-3 sec-1) for rate, R, of an ion dissolving from a mineral
where n is a constant, p is the average stoichiometric coefficient, Q is the activity quotient, and Q/Keq is the saturation index (how far from equilibrium the mineral is)
Where B is a shape factor equal to 16π/3 for a sphere and 32 for a cube, is the interfacial free energy, Ω is the molecular volume, k is Boltzmann’s constant (1.38x10-23 J/K), T is temperature (K), S is the supersaturation ratio (C/Cs), and Г is a pre-exponential factor (around 1033±3 cm-3 sec-1 and approximated by (Г = D/(Ω^5/3) )