REFINING OF PRECIOUS METALS BY CRYSTALLIZ ATION METHODS

This paper presents limiting values of equilibrium distribution coeffi cients of the admixtures in precious metals Ru, Rh, Pd, Os, Ir, Pt, Ag , Au and the periodical correlation dependences of the distribution co efficients on the proton number of admixtures. The presented values of k(o) and correlative relations give a possibility: -to determine the unknown k(o) values and to predict the behaviour of admixtures during crystallization processes, -to estimate the practical realization of z one melting or directional crystallization of various basic substances to choose suitable materials for those processes and to predict the r efining grade, -to prognose the distribution ability and enriching of foreign admixtures with k(o) > 1 on the dendritic axis and accumulatio n of admixtures with k(o) < 1 in the interdendritic spaces in mother m elt during dendritic segregation which always accompanies the solidifi cation of substances.