Concentration changes upon closed-system crystallization

2 Concentration changes upon closed-system crystallization 

A homogeneous mass Mliq of liquid contains the amount m,iq of species i. The concentration Cliq of species i in the liquid is defined as 

The fraction F of residual liquid is relative to that of parent magma M0 

Let D be the ratio of the concentration dmso, /dMsoi of species i in the last increment of precipitated solid to the concentration C,iq in the liquid, i.e., 

This is the fundamental distillation equation, often referred to as the Rayleigh law when in its integrated form (Rayleigh, 1896). As far as Dt is considered to be a function of F, this equation applies to the change of any species concentration in the course of phase separation. Liquid-vapor or solid-solid fractionations are liable to the same formulation. 

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