EN
Motivated by metallurgical and geophysical applications we present a mathematical model describing the process of unidirectional solidification of binary melts or solutions, which is based on the classical Stefan thermodiffusion theory with a planar front up to a time of mushy layer initiation and on the quasi-equilibrium theory of solidification with a constitutionally supercooled region afterwards. The role of boundary conditions imposed at the cooled wall is studied in terms of heat flux coefficients describing ultimately nonlinear dynamics of the process.