Abstract:Effects of sodium hydroxide concentration, ratio of liquid to solid, leaching temperature, and leaching duration on leaching rates of tellurium, lead, and selenium from Venturi sludge were investigated. The results show that leaching rate of tellurium, lead, and selenium is 94.7%, 39.9% and 20.5% respectively under the optimum conditions including sodium hydroxide concentration of 100 g/L, ratio of liquid to solid of 5, leaching temperature of 60 ℃, and leaching duration of 1 h. Lead extraction is effectively inhibited by two-stage leaching. Tellurium dioxide with TeO2 content of 98.5% above is prepared from secondary leaching lixivium by adding sulfide to remove lead and acidification to precipitate tellurium.