Establishment of "Structure-Efficiency" Relationship in Ultra-High Purity Metal Systems: Multi-Scale Analysis of Tellurium as a Prototype.

As critical strategic materials, ultra-high-purity scattered metals play roles across cutting-edge technological domains. Significant challenges remain in investigating the spatial location and chemical environment of impurities in high-purity systems due to the limitations of conventional thermodynamic techniques and characterization resolution, hindering the improvement of purification efficiency. In this study, using tellurium as a model, a cross-scale methodology is developed to elucidate the correlation between structural evolution and impurity separation efficiency. Experimental results show that increasing fusion rates induced transitions in growth orientation from (104) to (012) with reduced impurity content, accompanied by the morphological evolution from irregular to columnar grains. Phase-field simulations reveal that the interface structure and grain competition drove the orientation transitions from (001) to (012). Density functional theory calculations confirmed the thermodynamic superiority of the (012) orientation, demonstrating weaker impurity adsorption at liquid / (012) interfaces versus liquid / (104). Based on these mechanisms, the Bridgman method is employed to enhance the preferred orientation in the tellurium crystal, significantly improving its purification efficiency. This multi-scale investigation establishes a comprehensive framework for understanding the "structure-efficiency" relationship in ultra-high-purity metals, providing theoretical guidance for the development of targeted deep purification technologies.