Crystal Growth through the Medium of Nonautonomous Phase: Implications for Element Partitioning in Ore Systems

The phenomena related to the crystal growth in close-to-natural multicomponent systems have been considered. It is shown that the distribution of rare-earth elements in magnetite and hematite and the distribution of noble metals (NMs) in pyrite and magnetite are controlled by surficial nonautonomous phases (SNAPs). The increase in the fractionation and cocrystallization coefficients of elements is related to the presence of these phases. The dependence of SNAPs on the physicochemical growth conditions suggests typomorphism of mineral surfaces. The SNAP evolution during crystal growth explains some specific features of mineral growth systems, in particular, the existence of highly determinate dependences of uniformly distributed incompatible element admixture on the specific surface area of crystal, as well as the formation of nano- and microinclusions and microzonality in crystals. The results obtained are important for the ore formation theory and the practical estimation of the economic potential of ore deposits in view of determining the "hidden" metal content and elaborating a rational technology to recover ore material resources.