Effect of Allocation and Allocation Avoidance Methods on Life-Cycle Impact Results for Tellurium Production from Copper Anode Slimes

The global transition toward green energy has increased demand for metals and intensified the need for sustainable supply sources. Tellurium (Te), an essential metal for photovoltaics technology, is produced primarily as a by-product of copper refinery slimes treatment. This study conducts a life-cycle assessment (LCA) study of Te production to investigate the effect of environmental impact allocation choices on LCA results in multi-product metal systems. A cradle-to-gate LCA model of the Te product system was developed in SimaPro v9.5.0.1 software by combining industrial data, Ecoinvent v3.7.1 datasets, and literature information. Environmental impacts were quantified using the ReCiPe v1.04 Midpoint method for a functional unit of 1 kg of refined Te. The product system’s multi-functionality was investigated using mass and economic allocation and a system sub-division method. Sensitivity analyses examined the effects of the Te concentration in anode slimes and their recovery efficiency on impact estimates. The results show that mass allocation assigns higher burdens to Te than economic allocation does. System sub-division yields significantly lower impacts than allocation procedures by attributing burdens only to Te-specific recovery processes. Higher Te grades and improved recovery efficiencies markedly reduced impact estimates. These findings demonstrate the importance of allocation choices on the LCA of by-product metals.