Efficient Separation and Recovery of Tellurium and Copper from High-Value-Added Industrial Copper Telluride Slag by a Sustainable Process

Copper telluride slag is a ubiquitous intermediate by-product produced in the comprehensive recovery of tellurium from copper anode slime. Existing tellurium recovery/treatment processes consist of oxidizing leaching, precipitation, alkaline leaching, and electrolysis, which suffer from excessive consumption and generate high amounts of toxic hazardous waste. Herein, a clean and efficient process is proposed. This process includes the separation of Cu and Te by soda smelting, followed by leaching and precipitation to prepare TeO2, and the recovery of elemental Te by vacuum carbothermal reduction. The results showed that Te and Cu existing as cuprous telluride (e.g., Cu2Te, Cu0.64Te0.36, and Cu7Te4) in the raw material had been converted into upper stratum sodium tellurite slag and lower stratum copper oxide phase after soda smelting at 1273 K for 4 h. 83.54% grade TeO2 was precipitated by the neutral leaching and acid precipitation of sodium tellurite slag at pH 4-6, with a tellurium precipitation ratio of 99.08%. Elemental Te was directly separated and recovered by vacuum carbothermal reduction at 873 K for 1 h with 15% carbon content. The comprehensive recovery of tellurium exceeded 90% during this process and its purity reached 99.83%. The converted copper oxide could then undergo the copper smelting process for further copper extraction. This study confirmed the process as a sustainable and highly efficient method to extract tellurium and copper from copper telluride slag, which is of profound significance for the profitability and development of the tellurium metallurgical industry. [GRAPHICS] .