China Nonferrous Metallurgy

In this study, “sulfide leaching-selective reduction” process was proposed for tellurium recovery. The copper telluride slag and refining slag from the silver separation furnace in the process of anode slime treatment process was used as the raw materials in this study. In the sulfide leaching process, the sodium sulfide excess coefficient was 10 and 6 times, the solid to liquid ratio was 10∶1, the rotation speed was 400r/min, the temperature was 90℃ and 40℃, and the time was 3h. Under these conditions, the tellurium leaching efficiencies of the two were 97.00% and 99.75%, respectively. In the directed reduction process, the sodium sulfite excess coefficient was 5 times, the rotation speed was 400r/min, the temperature was 70℃, and the time was 3h. Under these conditions, the tellurium reduction ratios of the two were 99.75% and 91.49%, respectively. The total tellurium recoveries of the two were 96.76% and 91.26%, respectively. The purity of coarse tellurium powder was higher than 99%. The selenium in the waste liquid after selective reduction was further recovered. The excessive sodium and sulfur in the waste liquid can be recovered by evaporation and crystallization after oxidation. Generally, the total process performed good adaptability, high recovery, high product purity, low cost and short process flow in tellurium recovery.