Efficient Separation and Enrichment of Tellurium from Copper Anode Slime

During the treatment of copper anode slime, tellurium-bearing solutions are typically multi-component and complex, presenting significant challenges for tellurium recovery. Traditionally, the copper powder reduction method is employed, however, challenges remain in controlling phase transformations and achieving efficient mass transfer, resulting in excessive copper powder consumption. To address these challenges, this paper introduced an innovative technique termed the oxygen-deficient pressure precipitation method (OPPM). This method minimized copper loss in high-chloride solutions, enhanced the mass transfer kinetics of copper powder, and enabled efficient tellurium extraction from high-chloride solutions derived from copper anode slime treatment, using only a moderate amount of copper powder. The multiphase reaction thermodynamics of the Te-Cu-Cl-H 2 O system, the response surface analysis of the OPPM-enhanced tellurium precipitation process, and the kinetic mechanism of enhanced precipitation were investigated. The results demonstrate that prioritizing pH and adjusting to an oxygen-deficient environment to meet favorable reduction potentials ensures that the extraction of tellurium enhanced by OPPM is both thermodynamically feasible and kinetically efficient. The kinetic process of enhanced tellurium precipitation conforms to the Avrami kinetic model with an Avrami index of 0.8189, indicating diffusion control process with an apparent activation energy of 23.86 kJ/mol. Under the optimal OPPM condition, the tellurium precipitation efficiency reached 99.58%, and the copper powder consumption could be reduced by 50%. This process decreases chemical reagent usage and cost, providing a valuable reference for achieving efficient tellurium recovery.