Abstract
	During refining crystallization processes a distribution of admixtures and impurities at the phase interface occurs. The distribution of admixtures and impurities between solidus and liquidus phases is characterized by equilibrium distribution coefficient. Knowledge of the distribution coefficient is important for the choice of a convenient crystallization method of refining, preparation of single crystals and study of segregation micro- and macroinhomogeneities in real alloys. The equilibrium distribution coefficient represents the main material parameter for the preparation of high pure materials by refining processes as the zone melting and directional crystallization.
	In the paper the limit values of the equilibrium distribution coefficients of admixtures in Cr, Mo, Nb, Re, Ta, V, W as a result of the systematic study of solidus and liquidus curves in binary systems basic metals - admixture are presented. The periodical dependencies of the distribution coefficients of admixtures on the admixture atomic number were determined for systems niobium - , vanadium - admixture.