An environmental-friendly process for recovery of tellurium and copper from copper telluride

Abstract

In the present study, a novel process for effective recoveries of Te and Cu from copper telluride from anode slime processing in copper smelters was proposed. The process consists of two hydrometallurgical steps of atmospheric alkaline leaching for Cu and Te separation, and TeO₂ precipitation with H₂SO₄ for Te recovery. The effects of NaOH concentration, liquid to solid ratio, temperature, H₂O₂ to Cu₂Te mole ratio, and reaction time on the dissolution behavior of tellurium were investigated. A Te leaching efficiency of about 91% was obtained under the optimal experimental conditions. The results of thermodynamic and kinetic analysis indicate that a lower temperature is favorable for the dissolution of Te, and mass transfer inside the solid particle is the rate-determining step. In addition, a mechanochemical-assisted leaching was conducted, by which Te leaching efficiency was enhanced to approximately 93% with ball milling at 180 rpm for 5 h. After Te leaching, H₂SO₄ was utilized to adjust the pH value of the Te-containing alkaline leach solution to 4.5 for TeO₂ precipitation. The crystallization of TeO₂ can be completed by reacting for 1 h and the overall tellurium recovery has reached nearly 90%.