China Nonferrous Metallurgy

Tellurium anode slime was produced in the tellurium electrowinning refining process, whose tellurium content accounts for 3% to 20% of the total tellurium content, which leads to a decrease in the direct yield of tellurium. The main component of tellurium anode slime is high sodium tellurite, which is insoluble loose granular or flaky crystals generated by the Oxygen at anode reacting with sodium tellurite, most of which settle to the bottom of the tank, and a small amount adhere to the cathode plate surface. The high valence tellurium salt will contain low valence tellurium salt in the process of crystal growth, sedimentation and adhesion, which will increase the loss of tellurium. The tellurium content in the anode slime can be controlled below 3%, the optimal index can reach 1.5%, by changing the anode structure, setting polyester bags on the anode, adding an appropriate amount of reducing agent in the electrolyte, increasing the oxygen removal facilities and stirring and washing the anode slime with hot alkaline solution. The main treatment methods of tellurium anode slime include acid leaching self-reduction method, mixed acid solution replacement method and sulfide reduction method, which method has its’ advantages and disadvantages, and can be selected according to the actual process.