The effect of pore diffusion on the dissolution of porous mixtures

When a suspended solid dissolves in acid, the dissolved ions can diffuse further into the suspension. In many cases, these diffusing ions will effect precipitation of the same solid that was initially dissolved. This effect, which depends on a non-linear solubility, can usually be successfully predicted by assuming that the process is diffusion controlled. The predictions depend on diffusion and dissolution proceeding in parallel, and so represent an extension of earlier analyses where diffusion and reaction occurred sequentially.